JP4535582B2 - Printer control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a control method for a printer that performs printing processing on media that are manually inserted, particularly media of different sizes. The present invention can be applied to a printer that performs a reading process in addition to a printing process.
[0002]
[Prior art]
  When printing on a medium in a printer, the size of the medium inserted into the printer (hereinafter sometimes referred to as the actual size) is the size designated by the host computer that gives print information to the printer (hereinafter referred to as the designated size). If it is different from this, various troubles occur. In particular, when the actual size is smaller than the specified size, the print head is detached from the medium, so the platen is contaminated with ink, or the pins of the print head collide with the platen or get caught by the medium and break. Need to prevent this.
[0003]
  In a conventional printer, the size of the medium to be printed from now is specified by the host computer, and the size of the medium that has been inserted into the printer is detected by some detection means, and the detected actual size matches the specified size. If it matches, the medium is transported to the printing position and the printing process is performed, but if it does not match, error processing, for example, return of the medium and / or error display, etc. is performed. The print head is prevented from being damaged due to a mismatch or printing in an inappropriate area.
[0004]
  In a printer having an automatic paper feeding mechanism, since the medium feeding position with respect to the conveyance path is constant, a plurality of medium sensors are provided on the straight line perpendicular to the medium conveyance direction as a reference. The medium size can be easily detected depending on whether the sensor is operated.
  However, in a printer that does not include an automatic paper feeding mechanism and manually inserts media, such as a printer that processes passbooks, checks, airline tickets, boarding passes, etc., the media insertion position by the operator is not necessarily constant. It is necessary to detect the position and size of the medium at the printing position.
[0005]
[Problems to be solved by the invention]
  In a printer in which media is manually inserted, a plurality of media sensors are provided on a straight line perpendicular to the media transport direction with reference to a predetermined position. Depending on which sensor detects the presence of media, A printer that detects the size of the medium that has been used is disclosed in Japanese Patent Laid-Open No. 8-238819.
  However, this prior art requires an operator to insert a medium with reference to the left end or right end of the conveyance path (side loading) or to insert the center of the conveyance path as a reference (center loading). Then, depending on one of them, the installation position of the medium sensor must be determined, and the processing method of the detection signal from each sensor for size detection must be changed.
  Therefore, since the medium must be inserted in accordance with a predetermined reference position, the burden on the operator is large, and the medium is not always inserted into the proper position in the correct posture. There are inconveniences such as occurrence or improper insertion and re-insertion is requested, or an error occurs in size detection and printing is performed in a portion other than an appropriate print area.
[0006]
  The present invention has been made in view of the above points, and the problem is that the operator can insert the medium at an arbitrary position without being restricted by the reference position, and has been transported to the printing position. It is possible to correctly detect the position and size of a medium in a state.
[0007]
  The mechanism for detecting the position and size of the medium according to the method of the present invention is such that a print head is provided with a medium sensor, and secondly, a print head home position detection mark is provided outside the maximum size medium.Mosquito(Hereinafter referred to as HPM) is provided to check the change state of the detection output voltage (hereinafter referred to as sensor level) obtained from the medium sensor as the print head is moved by the carriage, and the change state matches a predetermined pattern. When it is determined that HPM has been detected and the inserted medium is transported to the print position, the print head is moved again in a predetermined direction andFrom media sensorThe change state of the obtained sensor level is examined, and when the change state matches a predetermined pattern, it is determined that the end of the medium is detected, and the position detection and the print head between the both ends of the detected medium are detected. The size of the medium is detected from the moving distance. Here, since the “medium size” substantially refers only to the width of the medium, the term “width” is used below.
[0008]
  By the way, when the medium is manually inserted into the insertion slot, a skew in which the medium is inclined with respect to the transport direction is likely to occur. When skew occurs, the accuracy of position detection and width detection performed using the medium sensor provided in the print head is lowered.
  Therefore, another object of the present invention is to improve the accuracy of position detection and width detection by performing position detection and width detection by the medium sensor after automatically correcting the medium skew.
[0009]
[Means for Solving the Problems]
  In order to solve the above problems, the control method employed by the present invention is as follows.1 piece of light reflection sensorA medium sensor is provided and detected by the medium sensor at or near the platen.Has almost the same light reflectance as the mediumA home position detection marker is provided. (B) During the initialization operation performed immediately after the power is turned on, the print head is moved in a predetermined direction.1 stepMoveEvery time youThe detection output level obtained from the medium sensorThe detection output level is stored in the buffer memory in succession every three consecutive steps and every time one step is moved, and the detection output level stored in the buffer memory is sequentially compared with a reference level stored in advance. Is lower than the reference level, and the number of times the current detection output level is equal to the previous detection output level among the detection output levels is greater than or equal to a predetermined number.Determining whether the medium sensor and the print head moving mechanism are normal; andWhen the current detection output level, the previous detection output level, and the previous detection output level stored sequentially in the buffer memory are compared, and a predetermined condition is satisfiedThe home position detection marker is detected, and the home position of the print head is analyzed based on the detected home position detection marker.WriteAnd (iii) conveying the medium inserted into the printer after the homing operation control to a printing position, and subsequently moving the print head from the home position in a predetermined direction. ,Every time the print head moves one step in a predetermined directionA sensor information acquisition process for acquiring and storing a detection output level from the medium sensor;Current detection output level, previous detection output level, and detection output level two times beforeTheWhen sequentially comparing and satisfying a predetermined conditionDetecting the right and left edges of the medium;The print headFrom the home position to the medium right edge detection position and medium left edge detection positionWhen movingMedium width calculation processing for calculating the width of the medium based on the number of steps of the medium, and the mediumofRight end position,leftMedia width detection control including processing for storing the end position and medium width, and (d) when a print command is input, print processing is performed based on the stored right end position, left end position, and medium width of the medium. It is characterized by performing control.
[0010]
  Further, the method of the present invention checks the stored detection output level in the left direction from the home position side in the process of detecting the right end of the medium, and uses the stored detection output level in the process of detecting the left end of the medium. It is characterized by checking rightward from the opposite side of the home position.
[0011]
  The method of the present invention preferably corrects the skew of the inserted medium in the vicinity of the conveyance roller closest to the medium insertion / discharge port of the printer.MediumA skew correction mechanism is provided, and the skew of the medium inserted into the printer after the homing operation isMediumAfter correction by the skew correction mechanism, it is preferable to carry it to the printing position.
[0012]
  A printer using the method of the present invention is as follows.In a printer that prints on a predetermined area of a medium supported by the platen by a print head that is moved in the longitudinal direction of the platen, the medium sensor configured by a light reflection sensor for detecting the medium present at the printing position is provided. Provided in the print head, a home position detection marker having substantially the same light reflectance as that of the medium detected by the medium sensor is provided in the platen or the vicinity thereof, and the detection output level of the medium sensor is large or small in the storage unit. A reference level register for storing a reference level for determining the output level, and three consecutive detection output levels (previous level, previous level, and current level) that are sequentially acquired from the medium sensor each time the print head moves one step. ) Sensor information storage buffer and the right end position of the media acquired by the media width detection described later A data storage unit for storing each data of the left end position and the medium width, and the control unit includes a homing operation control unit for determining whether the medium sensor and the print head moving mechanism are normal immediately after the power is turned on, a platen Transport control means for transporting the medium inserted in the platen to a predetermined position of the platen, carriage motor control means for moving the print head in the longitudinal direction of the platen, and sensor information acquisition for acquiring a detection output level from the medium sensor Means for detecting the right and left edges of the medium using each detection output level stored in the sensor information storage buffer memory, and for the print head to move from the right edge detection position to the left edge detection position. Medium width detecting means for detecting the width of the medium from the number of steps and the print data input based on the left end / right end / width detection. Printing control means for performing printing in a predetermined printing area, and the homing operation control means is configured to perform the initialization every time the print head is moved by one step in a predetermined direction during an initialization operation performed immediately after power-on. The detection output level obtained from the medium sensor is stored in the buffer memory in succession every three steps and every time one step is moved, and the detection output level stored in the buffer memory is stored in advance as a reference level. According to whether or not the number of times the detection output level is lower than the reference level and the number of times the current detection output level is equal to the previous detection output level among the detection output levels is equal to or greater than a predetermined number. And a process for determining whether or not the print head moving mechanism is normal, a current detection output level sequentially stored in the buffer memory, The detection output level is compared with the detection output level at the previous time, the home position detection marker is detected when a predetermined condition is satisfied, and the home position of the print head is analyzed based on the detected home position detection marker. The medium width detecting means conveys the medium inserted into the printer after the homing operation control to a printing position, and then moves the print head from the home position to a predetermined direction. Sensor information acquisition processing for acquiring and storing the detection output level from the medium sensor each time the print head moves one step in a predetermined direction, and stored current detection output level and previous detection output level. And the detection output level is compared sequentially and the right end of the medium when a predetermined condition is satisfied. And a medium width calculation process for calculating the width of the medium based on the number of steps when the print head is moved from the home position to the medium right edge detection position and the medium left edge detection position; The present invention is characterized in that medium width detection control including processing for storing the right end position, left end position and medium width of the medium is performed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
  Next, an embodiment of a printer using the method of the present invention will be described with reference to the drawings. A medium skew correction mechanism for promoting the utility of the present invention will be described first with reference to FIGS.
  FIG. 1 is a schematic side view showing the main part of the printer, and FIG.MediumFIG. 3 is a side view of a main part showing a pinch roller pressing force adjusting means which is one component of the skew correction mechanism, and FIG. 3 is a side view of a main part showing a skew correction stopper lifting means which is another component of the skew correction mechanism. 4 is a plan view showing a part of the stopper lifting / lowering means, FIG. 5 is a plan view showing the principle of medium skew correction, and FIG. 6 is a block diagram showing an example of means for realizing the main functions of the printer of the present invention. FIG.
[0014]
  As shown in FIG.Media skew correction mechanismSCMeans 5 for adjusting the pressing force of the pinch roller pr1, which will be described later, means 7 for raising and lowering the skew correction stopper 70,As shown in FIG.A conveyance motor control unit 81 provided in the control unit 8 and a cam motor control unit 8 for skew correction.2 andIt is comprised by.
[0015]
  In FIG. 1, 1 is a medium setting stage, 2 is a medium insertion / discharge port, 3 is a conveyance path constituted by upper and lower conveyance guides 3 a and 3 b, and 4 is a conveyance means for conveying the medium along the conveyance path 3. . The transport unit 4 includes a transport motor M1 and transport rollers R1 to R3 including a plurality of pairs of upper and lower pinch rollers pr1 to pr3 and drive rollers dr1 to dr3. A medium presence / absence sensor Sa is provided at a position immediately after entering the conveyance path 3 from the medium insertion / discharge port 2.
[0016]
  The pinch roller pr1 of the transport roller R1 provided at the position closest to the medium insertion / discharge port 2 is provided with a pressing force adjusting means 5 for adjusting the pressing force with respect to the drive roller dr1 provided to the pinch roller pr1. ing.
  As shown in FIG. 2, the pressing force adjusting means 5 supports the pinch roller pr1 in a vertical groove 52 of the support member 51 so that the pinch roller pr1 can be raised and lowered, and a leaf spring 54 whose tip is in contact with the upper surface of the shaft 53 of the pinch roller. Is fixed to one end of the lever 55. The lever 55 isaxisA roller 57 provided at the upper end of the lever is brought into contact with the peripheral surface of the first cam 58 fixed to the rotary shaft 6.
  The rotating shaft 6 is rotated by a predetermined angle in a predetermined direction by the cam drive motor M2. When the concave portion 58a of the first cam 58 is in contact with the roller 57, the lever 55 does not apply a force to the leaf spring 54, so that the pinch roller pr1 has almost the same pressing force against the drive roller dr1.pr1It corresponds to only its own weight. On the other hand, when the rotation shaft 6 is rotated by the cam drive motor M2 and the convex portion 58b of the first cam 58 is in contact with the roller 57, the lever 55 applies a downward force to the leaf spring 54. The pressing force of the roller pr1 against the drive roller dr1 increases.
[0017]
  As shown in FIGS. 1, 3, and 4, a skew correction stopper 70 that blocks or opens the conveyance surface is provided immediately after the conveyance roller R <b> 1 provided at a position closest to the medium insertion / discharge port 2. It can be moved up and down. Stopper 70 has front half 71ButIt is formed in a plate shape, the latter half portion 72 is bent or curved into a letter shape, and is cut out to escape the pinch roller pr1, and the planar shape is formed in a comb-tooth shape, and is provided above the conveying surface. The shaft 56 is supported so as to be swingable. The medium stop portion 72a formed at the lower end portion of the rear half portion 72 is pivoted by the stopper elevating means 7 so as to be raised and lowered between a position where the conveyance path is shut off and a position where it is opened. Yes.
  The stopper lifting / lowering means 7 is configured as follows. The upper surface of the front end portion of the stopper 70 isRotating shaft 6Is in contact with the peripheral surface of the second cam 73 fixed to the head. The first cam 58 and the second cam 73 are positioned so that the latter concave surface 73 b contacts the stopper 70 when the former concave surface 58 a contacts the roller 57.
[0018]
  While the convex surface 73a of the second cam 73 is in contact with the upper surface of the front end portion 71 of the stopper 70, the stopper 70 is supported.axisThe medium stop 72a of the stopper 70 is raised above the conveyance surface and held at a position where the conveyance path 3 is not blocked.
  On the other hand, as shown in FIG. 3, the concave surface 73 b of the second cam 73 is the front end portion of the stopper 70.71While it is in contact with the upper surface of the stopper 70, the stopper 70axisSince it is rotated counterclockwise by a predetermined angle centering on 56, the medium stop portion 72a of the stopper is lowered below the transport surface and held at a position where the transport path 3 is blocked.
[0019]
  S1, S2, S3,... In FIG. 1, FIG. 4, and FIG. 5 are used to check whether or not the skew of the medium disposed on the straight line perpendicular to the transport direction immediately before the medium stop position by the stopper 70 has been corrected. This is a skew check sensor. Each of the skew check sensors S1, S2, S3... Is composed of a reflection or transmission type optical sensor, and two or more adjacent skew check sensors are turned on by the medium when the stopper 70 is stopped in a correct posture. It is installed as follows.
[0020]
  As shown in FIG. 6, the printer control device CONT includes a control unit 8 constituted by a CPU, and a storage unit 9 including a ROM 91 and a RAM 92, and the control unit 8 includes media conveyance and medium skew correction. Therefore, a conveyance motor control unit 81, a cam motor control unit 82, and a skew presence / absence determination unit 83 are provided. Various system programs stored in the ROM 91 include programs for medium conveyance and medium skew correction.
[0021]
  Next, the configuration of the medium skew correction mechanism and the operation of medium skew correction by executing the program will be described. FIG. 7 is a flowchart showing the overall operation from when the printer is turned on until the printing process for the inserted medium is completed. FIG. 8 is a flowchart showing details of the medium skew correction control in step 3 (hereinafter, step is represented by P) in FIG.
  The point that the homing operation (P1) is performed immediately after the power is turned on is the same as the conventional one. However, since this homing operation has one of the features of the present invention, this will be described later. Then, after the homing operation is normally performed, when the medium set on the medium setting stage 1 is manually inserted into the medium insertion / ejection port 2, the medium presence / absence sensor Sa detects the presence of the medium (Yes in P2 (Yes (Y )) Then, based on the detection signal, the transport motor control means 81 of the control unit 8 rotates the transport motor M1, and the cam motor control means 82 of the control unit 8 rotates the cam drive motor M2 by a predetermined step (P31). ). As a result, the rotation shaft 6 is rotated by a predetermined angle, and the concave surface 58a of the first cam 58 and the concave surface 73b of the second cam 73 are in contact with the roller 57 and the stopper 70, respectively. Since the leading edge of the medium is given a conveying force from the first conveying rollers pr1 and dr1, the medium is conveyed while maintaining its posture at the inserted position, and the leading edge of the medium abuts against the stopper 70. The posture of the medium at the time of bumping differs depending on whether or not the medium has a skew.
[0022]
  When there is no skew in the medium, the leading edge of the medium is in contact with the stopper 70 over the entire width, but as shown in FIG. 5, the medium PM has a skew {FIG.PM(A)}, the left or right part of the leading edge of the medium first hits the stopper 70 {FIG.PM(B)}. Now, since the pressing force of the pinch roller pr1 against the drive roller dr1 is reduced, the drive roller on the side that is in contact with the medium stopper 70 slips on the medium, and the medium has not yet hit the stopper 70 The side is advanced by the drive roller dr1 in contact therewith, so that the skew of the medium PM is corrected {FIG. 5PM(C)}.
[0023]
  As described above, based on the detection signal from the medium presence / absence sensor Sa, the transport motor M1 and the cam drive motor M2 are started by the control unit 8 and driven by predetermined steps, respectively, and the inserted medium is sucked at the same time. After the stopper 70 is lowered, the skew presence / absence determining means 83 of the control unit 8 takes in the detection signals of the skew check sensors S1, S2, S3... And the detection signals from two or more adjacent skew check sensors are turned on. It is checked whether or not (P32). If the determination is affirmative (Y), a fixed amount, for example, 4 mm (equivalent to the stepping of the transport motor 30) is sucked (P33).
[0024]
  In this additional conveyance, for example, two adjacent skew check sensors are turned on (dark) due to, for example, a medium adhering matter or the like, even though the leading edge of the medium has not reached the position where the skew check sensor is operated. In order to prevent an adverse effect caused by this, it is performed for the purpose of confirming that the two skew check sensors adjacent to the leading edge of the medium are turned on (dark).
  After the additional conveyance, the cam drive motor M2 is rotated again by a predetermined angle, and the stopper 70 is again raised to the retracted position and held, and at the same time, the pressing force of the pinch roller pr1 is restored (that is, the pinch roller pr1). (P34). Then, the control for medium skew correction is terminated.
  The print control means 810 of the printer control unit waits for an input of a print request signal from the host computer HC in a state where the inserted medium is corrected for skew (P4).
[0025]
  If the result is negative (N) in P32, that is, if two adjacent skew check sensors are not turned on (dark), the retry counter is incremented by 1 to determine whether the number of retries at that time has reached the maximum value. Judgment (P36)When the maximum value is not reached, the conveyance motor control means 831 of the control unit 8 reverses the conveyance motor M1 by a predetermined step, the cam motor control means 82 raises the stopper 70, and closes the pinch roller pr1 to remove the medium. Slightly returning (P38), the predetermined step rotation control (P31) of the conveyance motor M1 and the skew correction presence / absence determination process (P32) are repeated again a predetermined number of times until positive in P32. If the skew is not corrected after the predetermined number of retries and the number of retries reaches the maximum value (Y in P36), an error is displayed as an error in the medium or skew check sensor.as well asReturn the medium to the insertion / discharge port 2Error handling (P37)Then, the process ends.
[0026]
  The skew correction control described above is for when the processing mode is the passbook mode, that is, when the medium is strong such as a passbook, but when the processing mode is the single sheet mode, that is, the waist strength is small. In the case of a medium, when the pinch roller pr1 is closed after the additional transport, the front end of the medium may be held in a bent state. In this state, if the medium is transported in the direction of the print position in response to a print request from the host computer HC in P5 of FIG. 7 after the skew correction operation is completed, skew or jam may occur. There is a fear. In order to prevent this, when the single sheet mode is set at the start of printer use, after the additional conveyance (P33), the pressing force of the pinch roller pr1 is gradually attenuated (open the pinch roller pr1). Then, the bending of the front end portion of the medium is eliminated, and then the stopper 70 is opened, the pinch roller pr1 is closed (P34), and the input of the print request signal from the host computer is waited (P4). It is configured.
[0027]
  When the print request signal is input (Y in P4), the print control means 810 causes the carry motor control means 31 to rotate the carry motor M1, and the carry means 4 carries the medium in the print position direction (P5).
[0028]
  When the leading edge sensor Sb provided between the conveying roller R1 and the print head H detects and outputs the leading edge of the medium (Y in P6), the conveying motor control means 31 resets a step counter (not shown), and When the count value matches the number of steps necessary for the medium to reach a predetermined print line from the time when the detection signal is input (Y in P7), the rotation of the carry motor M1 is stopped (P8). That is, the conveyance is stopped when the medium reaches a predetermined printing position.
[0029]
  In the present invention, as indicated by P1 in FIG. 7 and as described above, immediately after the printer is turned on, the print head H, which is one point of the present invention, is called a home position (hereinafter referred to as HP). ) Is performed, and then the medium skew correction operation (P3) is performed when the medium presence sensor Sa detects the medium (Y in P2), and Then, before the printing process (P11) is performed on the medium conveyed to the predetermined printing position, the medium position detection and width detection (P9), which are another essential point of the present invention, are performed. Yes.
[0030]
  Then, next, the homing operation of P1 in FIG. 7 and the medium position detection and width detection of P9 will be described in order.
  FIG. 9 is a plan view of the main part showing the positional relationship between the medium sensor Sc and the HPM provided in the print head H. 3c and 3d are a left conveyance guide and a right conveyance guide that form a conveyance path 3 for conveying the medium PM. It is. FIG. 10 is an explanatory diagram illustrating a change state of the sensor level when HPM is detected by the medium sensor Sc.
  11 is a main flowchart of the homing operation (P1), FIG. 12 is a sub-flowchart showing details of the leftward movement process (P103) in the main flowchart of FIG. 11, and FIG. 13 is a rightward movement in the main flowchart of FIG. FIG. 14 is a summary flowchart showing generally the flow of the main operation of the process (P105), FIG. 14 is a sub-flowchart showing a part (1/4) of the details of the rightward movement process (P105) in the main flowchart of FIG. 15 is a sub-flowchart showing a part (2/4) of the rightward movement process, FIG. 16 is a sub-flowchart showing a part (3/4) of the rightward movement process, and FIG. It is a sub-flowchart which shows a part (4/4).
  18 is a diagram illustrating the principle of HPM right edge detection, FIG. 19 is a diagram illustrating the principle of peak value detection, and FIG. 20 is a diagram illustrating the principle of calculating a peak intermediate value.
[0031]
  The print head H isAs shown in FIG.The guide shaft 10 is supported so as to be movable in a direction perpendicular to the medium conveyance direction.TheThe carriage 11 is fixed to the carriage 11, and the carriage 11 is configured to be moved by a carriage motor M3 via a timing belt (not shown). The medium sensor Sc is composed of a reflective optical sensor and is attached to the print head H toward the medium conveyance surface. The medium sensor Sc has a capability of detecting the presence or absence of the medium based on the difference between the light reflectance of the platen and the light reflectance of the medium when the print head is moved. Accordingly, the HPM is composed of a sheet having a light reflectance substantially equal to that of the medium, and is added by a carriage motor M3.SpeedIn the box, it is pasted on or near the upper surface of the platen.
[0032]
  Among the system programs stored in the ROM 91, there is a program for controlling a homing operation that is first read and executed by the control unit 8 immediately after the printer is turned on.
  As a hardware configuration for performing the homing operation, as illustrated in FIG. 27, the RAM 92 of the storage unit 9 includes a reference level register 921 configured by a nonvolatile memory, and the reference level register 921 includes a medium. The voltage level output by the sensor Sc, that is,Detection output level (sensor level)A reference level SL for determining the height of the is stored. This reference levelSL can be changed to an arbitrary value when the printer is set to the test mode. Further, the RAM 92 is provided with a comparator value register 922. As will be described later, the comparator value (normal value) for enabling the determination of the sensor level based on the value of the reference level to be executed with stability. Is stored.
[0033]
    [Homing operation control]
  When the execution of the homing operation control program is started, the operation proceeds according to the main flow shown in FIG. 11, and first, a retry counter is set (P101). In other words, when the sensor level is detected later, if it cannot be detected due to noise, dust, or a medium sensor failure, a retry operation is performed, but the maximum number of retry operations is set. To do.
[0034]
  Next, the comparator value is set (P102). The comparator value is obtained from the medium sensor Sc.DetectionIn the present invention, this is a removal constant when the comparator function normally performed by an electronic circuit for removing noise and other unnecessary level changes from the output is processed by software. In other words, since the medium sensor Sc detects while moving, its output waveform includes various waveforms (disturbances), so it is difficult to determine where the sensor level is the MAX level and where is the MIN level. In order to solve this problem, every time a drive pulse is applied to the carriage motor M3, that is, every time the print head H moves by one step, a constant division and multiplication are performed on the sensor level obtained from the medium sensor. The process of eliminating the disturbance is performed by discarding fractions. Since the function of this comparator is realized by software, there is an advantage that it does not cost as in the case of using a hardware configuration. In this embodiment, the comparator value is set to 0.1 as the normal value.
[0035]
  [Left direction processing]
  Subsequent to the comparator value setting, each time a drive pulse is given to the carriage motor M3, a leftward movement process (P103) is performed as an interrupt process. The basic purpose of the leftward movement process is to determine whether the media sensor and the printhead movement mechanism operate normally or whether the HPM is dirty before performing the process of detecting the printhead HP. There is to check.
[0036]
  In order to execute the leftward movement process, as shown in FIG. 27, a RAM 92 is provided with a first sensor information storage buffer memory 923, and the sensor information storage buffer memory includes three sensor levels that are temporally continuous. Area to store sequentially, i.e.SensorlevelThe first to storeArea 923a, Last timeSensorlevelSecond to storeArea 923b and this timeSensorlevelThe third to storeArea 923cIs provided. FIG. 27 shows the storage contents of the RAM 92 and the storage hierarchical structure.
[0037]
  When the leftward movement process (P103) is started, as shown in FIG. 12, the sensor information acquisition process (P201) before taking in the sensor level (hereinafter referred to as the previous time level) in the first area 923a, and the second area 923b. The previous sensor information acquisition process (P202) for capturing the previous sensor level (hereinafter referred to as the previous level) and the current sensor information acquisition process (P203) for acquiring the current sensor level (hereinafter referred to as the current level) in the third area 923c. And do.
  Each time the print head is moved by one step, in the sensor information acquisition process (P201), the previous sensor level stored in the second area 923b is moved to the first area 923a and the previous level (FFL). In the previous sensor information acquisition process (P202), the current level stored in the third area 923c is moved to the second area 923b to be the previous level (FL), and the current sensor information acquisition process (P203). In FIG. 4, the latest output from the medium sensor Sc is taken into the third area 923c and is set to the current level (PL).
[0038]
  The comparator function is operated in the sensor information acquisition process (P203) this time, and the voltage value input from the medium sensor Sc is divided and multiplied by the comparator value to remove noise and the like from the sensor level, and is easy to process. It is configured to change to a value and capture as the current level (PL).
[0039]
  In this way, three consecutive sensor levels are acquired and stored, and are sequentially exchanged for each step, and the three sensor levels are compared with the reference level (SL), thereby comparing the voltage level obtained from the medium sensor Sc. It is possible to recognize what kind of waveform is drawn by the change state. In this specification, a sensor level higher than the reference level SL will be referred to as a MAX level for convenience, and a sensor level lower than the reference level SL will be referred to as a MIN level for convenience.
[0040]
  The processing from P204 to P208 in FIG. 12 is performed by the medium sensor Sc in FIG.Circle 1, Circle 2, Circle 3Whether the medium sensor Sc and the print head moving mechanism (that is, the carriage motor M3, timing belt, etc.) are normal or whether the HPM is dirty is determined regardless of where the movement starts. Is to do.
  First, in P204, it is determined whether or not the number of steps from the movement start point of the print head exceeds a predetermined number of steps that defines a movement limit. That is, the control unit 8 is provided with a step counter C1 that counts every time one step is given to the carriage motor M3. Each time the sensor information acquisition process is performed, the value of the step counter (total number of steps) exceeds the movement limit. When the total step over is determined, it is determined that the medium sensor or the print head moving mechanism is not normal or the HPM is dirty, and an error display is displayed on the display unit (not shown) later. Therefore, an error set (P210) such as setting an error flag bit is performed.
[0041]
  If it is determined normal in P204, the first sensor information buffer memory 923No. 3 area 923c11 is compared with the reference level (P205), and if it is determined that the current level is higher than the reference level, the process returns to the main operation flow of FIG. In addition, the sensor information acquisition process (P201 to P203)as well asThe determination process (P204 to P208) is repeated. When it is determined in P205 that the current level is equal to or lower than the reference level, it is determined whether or not the current level is equal to the previous level (P206). If it is determined that they are not equal, the process returns to the main operation flow of FIG. If it is determined in P206 that the current level is equal to the previous level, the MIN level detecting counter C2 provided in the control unit 8 of FIG. 6 is incremented (+1) (P207).
[0042]
  Then, whether or not the value of the MIN level detecting counter C2 has reached 50, that is, the output level of the medium sensor(Sensor level)Is in the MIN level, it is checked whether or not the medium sensor has continued for 50 steps (P208). When the MIN level count value is less than 50, the process returns to the main operation flow of FIG. 11, and the interrupt process is restarted from P201 again when the next step is applied. In P208, when the MIN level count value reaches 50, it is determined that it is normal and the rotation of the carriage motor M3 is stopped (P209), the print head H, and hence the medium sensor Sc, is stopped, and interrupt processing is performed. This leftward movement process is terminated.
  That is, as described above, the change state of the sensor level of the medium sensor Sc when the print head H moves to the left from the stop position STL at HP is as shown in FIG. The start position (starting point) of the leftward movement isCircle 1, Circle 2, Circle 3If the state where the sensor level is the MIN level continues for 50 steps or more, the medium sensor and the print head moving mechanism are determined to be normal.
[0043]
  More specifically, the starting point of the medium sensor Sc is shown in FIG.1 roundIn other words, when it exists on the left side of HPM, even if the medium sensor moves in the left direction, a determination pattern that the current level is always smaller than the reference level and equal to the previous level is formed, and the MIN level count value When the value reaches 50, the carriage motor M3 is stopped.
  Also, the starting point of the media sensor is shown in FIG.Round 2In other words, if it exists above the HPM, the current sensor level moves to the left after the HPM moves to the left after the state where the current sensor level is higher than the reference level continues to a predetermined step as the medium sensor moves to the left. A determination pattern in which the current level is equal to the previous level is formed after that is smaller than the reference level SL, and when the MIN level count value reaches 50, the carriage motor M3 is stopped.
  Furthermore, the origin of the media sensor is shown in FIG.Round 3In other words, when it exists on the right side of HPM, the medium sensor moves to the left and continues to a predetermined step in which the current level is higher than the reference level SL until reaching the left end of HPM, and then moves to the left of HPM. From this point, a determination pattern is formed in which the current level is smaller than the reference level, and thereafter, the current level is equal to the previous level. In any case, it is determined that the level is normal.
  However, for example, even if a piece of paper or the like is present on a conveyance path in a place other than the HPM, the current level continues to be higher than the reference level, or the current level is less than or equal to the reference level. As an example, the state in which the current level is not equal to the previous level is not continued until the value of the step counter C1 reaches 200 steps.Of FIG.At P204, the total step is over, and the result of the leftward movement process is not determined to be normal, and an error set (P210) is made.
[0044]
  The reason why 200 steps or more are used as the judgment criteria for total step over is that the movement range of the medium sensor in which the current level is equal to or smaller than the reference level is a position that has moved 200 steps to the left from HP. Based on what is included in.
[0045]
  [Move right]
  When the result of the leftward movement process is determined to be normal,Of FIG.A rightward movement process (P105) in the main flow of the homing operation control is executed. The rightward movement process is executed according to the flowcharts shown in FIGS. 13 and 14 to 17 every time the print head moves one step in the right direction. As shown in FIG. 13, this rightward movement process is generally a process (P30A) of detecting the left end of the HPM from the sensor level change state output when the medium sensor Sc moves above the HPM. The process includes a process of detecting a peak value from the sensor level change state (P30B) and a process of analyzing the HP stop position based on the detected peak value (P30C). In other words, the rightward movement process is ultimately for determining the HP of the print head, but moves from the stop position when the previous leftward movement process ends to the right end of the printhead stroke. However, by analyzing the output level obtained from the medium sensor Sc, the width of the HPM is detected, and the stop position that is predetermined at a predetermined distance from the HPM, that is, the actual HP is determined. .
[0046]
  To perform the rightward movement process,As shown in FIG.The RAM 92 of the storage unit 9,It has three flag memories (924a to 924c) that determine the order in which sensor levels are detected. The first flag memory 924a has a flag for detecting the MAX level, the second flag memory 924b has a flag for detecting the peak level after the MAX level detection is finished, and the third flag memory 924c has The flag for detecting the MIN level after the end of the peak level detection is sequentially set alternately under the predetermined condition, that is, after detecting the MAX level and then detecting the peak level. It is.
[0047]
  When the rightward movement process starts,HP pattern left edge detection process P30A is executed,Whether a flag is set in the first flag memory 924a, that is,As shown in FIG.It is checked whether the MAX level is currently detected (P301). If the MAX level is being detected, P302 to P312 are performed. In P302 to P305, using the sensor levels of the three areas 923a to 923c of the first sensor information buffer memory 923, the current level is compared with the previous level and the previous time level under a predetermined condition. When the difference is larger than the comparator value, the current level is set as the MAX value, and the MAX value storage buffer 926Save to a. If the current level thereafter is further higher than the previous level, the MAX level of the MAX value storage buffer is updated. Thus, the MAX value storage buffer 926The maximum MAX value is stored in a.
  In the waveform rising to the right of the HP pattern in FIG. 18, by the above MAX level detection,1 roundMaximum MAX value ofThat is, the left end of HPIs detected.
[0048]
  When the current level matches the previous level and the previous level during the MAX value detection, it is determined that the value is the peak value, and the next peakvalueIn order to execute the detection, a peak value detecting flag is set in the second flag memory 924b (P306), and the peak counter C3 provided in the control unit 8 is incremented (+1) (P307).
  If the comparison result of the three pieces of sensor information does not satisfy the condition for detecting the MAX level, an HP non-detection error is set (P310, P311, P312).
[0049]
  [Peak detection]
  When the medium sensor Sc moves one step to the right after the peak value detecting flag is set in P306, it is determined in P301 that the level other than the MAX level is detected, and the process proceeds to P313. In this step, it is determined that the peak level is being detected. Thus, in P314 to P317, the current level is compared with the previous level and the previous level. If it is determined in P315 and P321 that the current level is equal to the previous level, the value of the peak counter C3 is required to be moved while the medium sensor detects the right end to the left end of HPM in P322. Whether the peak counter value is smaller than the reference value or the peak count value is larger than the reference value, which is equal to the reference value (the number of steps corresponding to the HPM width of 7 mm) set in advance as the correct step number To do.
[0050]
  If the former is determined, the peak counter C3 is incremented. When the medium sensor Sc is moving above the HPM, the peak counter C3 should be updated (+1) while the print head is moved by the number of steps corresponding to the maximum level of 7 mm which is the HPM width. is there. Actually, the number of steps at which the sensor level maintains the MAX level is slightly smaller than the number of steps corresponding to 7 mm.
  When the latter is determined, that is, when it is determined in P322 that the peak count value is larger than the reference value, for example, it is determined that a piece of medium or other foreign matter is sandwiched on the platen, and the HP pattern A mismatch error is set in the abnormality determination buffer 927, and the interruption process of the rightward movement process is terminated.
[0051]
  After the flag for detecting peak level is set (P306), it is determined in P314 that the current level is lower than the previous level, or in P315 after the current level is determined to be equal to the previous level, the current level is higher than the previous level in P321. Is determined to be smaller, or the current level is lower than the previous level in P315, P316 In this case, it is impossible to determine that the previous level is higher than the previous level. Therefore, in these cases, the rightward movement process is performed after error setting (P320, P324, P329). This interrupt processing is terminated.
[0052]
  In P317, when it is determined that the previous level is smaller than or equal to the previous level, in the former case, it is determined that the current level has become the MIN level, and the third flag memory 924c is stored. The MIN level detecting flag is set (P318), and then the MIN level detecting counter C2 is incremented by 1 (P319), and the process returns to the main flow of FIG. In the latter case, that is, when it is determined that the previous level is equal to the previous level, the MIN level detecting counter C2 is incremented by 1 (P319 ′), and the process returns to the main flow of FIG.
  Further, when the previous level is equal to or smaller than the previous level in P326, the peak count value is compared with the HPM width (P327), and when the peak count value is larger than the HPM width, An HP pattern mismatch error is set (P340), and the interruption process of the rightward movement process is terminated. On the other hand, if the peak count value is equal to or smaller than the HPM width, the peak detection counter is incremented by 1 (P328), and the flow returns to the main flow of FIG.
[0053]
PAfter it is determined in 326 that the previous level is lower than the previous level, in P328Peak valueThe meaning of updating the detection counter (+1) is to move the print head to the right limit because the print head can move rightward for 5 steps even after the medium sensor detects the right end of HPM.
[0054]
  As described above, peak value detection processing(P30B)In FIG. 19, when the current level matches the previous and previous sensor levels, the number of steps in which the peak state continues is counted. Then, the current level is compared with the previous and previous sensor levels during peak value detection, and when the current level is small, it is determined that the right end of the HPM has been detected. Further, the MIN level detection flag is set in the third flag memory 924c, and the next HP stop position analysis process is performed.(P30C)Transition to.
[0055]
  After the MIN level detection flag is set, it is checked in P341 whether the count value of the MIN level detection counter has reached 5 or not. If it is less than 5, the current level is compared with the previous level ( P345), if it is equal to or greater than the previous level, it is not normal, so an error is set (P347), and the interruption process of the rightward movement process is terminated. However, if the current level is smaller than the previous level in P345, the MIN level detecting counter C2 is updated (P346), and an interrupt process at the next one step is awaited.
  On the other hand, when the count value of the MIN level detecting counter C2 reaches 5 or more in P341, an intermediate value (peak intermediate value) of the distance at which the peak level is detected is obtained by calculating the following equation ( P342).
            PKc = {TSC- (PC / 2) -MINC}
  However, PKc is the peak intermediate value, TSC is the total step count value, PC is the peak count value, and MINC is the count value of the MIN level detecting counter, that is, 5.
  In short, as shown in FIG. 20, the peak intermediate value PKc indicates the number of steps corresponding to the diagonal line from the point Pb moved rightward by 5 steps from the right end Pa where the MAX level which is the current stop position of the medium sensor Sc is detected. It corresponds to the position returned to.
[0056]
  If the peak intermediate value PKc has been obtained, the number of steps required to move the print head from the current position to the HP stop position is calculated (P343). In this case, the HP (stop position) is a position moved 8 steps in the right direction from the right end of the HPM. Further, the peak intermediate value obtained in P342 is processed as being coincident with the HPM intermediate point. Thus, at P343, HP is the following formula:
    HP (step) = PKc + 3.5 mm / 0.2 + 8
That is, the peak intermediate value (PKcThis is obtained by calculating the number of steps corresponding to 3.5 mm, which is half the distance of HPM, and a formula that adds 8 steps.
[0057]
  Then, at the last P344, the carriage motor M3 is driven and controlled by a predetermined step based on the calculation result, the print head H is moved to HP, the rightward movement process is terminated, and the process returns to the main flow of FIG.
[0058]
  In P106 of FIG. 11, it is checked whether or not an error has been set in each of the steps P311, 312, 320, 324, 323, 329, 340, and 347 of the rightward movement process. That is, when the print head is normally moved to the HP stop position, the homing operation control is terminated, and the process proceeds to P2 in the medium insertion standby in the entire flowchart of FIG.
  On the other hand, when an error set is made, the leftward movement step count value in the previous leftward movement process of FIG. 11 and the rightward movement step count value in the current rightward movement process are subsequently determined. And whether or not a step-out error has occurred in the carriage motor M3 is determined according to whether or not they match (P107). If a step-out error has occurred, an error is displayed on the display (P114), and the homing control operation is terminated.
[0059]
  If it is determined in step 107 that there is a step-out error, the retry counter C4(Down counter)It is checked whether or not the value of 0 has become 0 (P108). When 0 is reached, that is, when the maximum number of retries set in the retry counter is completed, an error is displayed on the display unit of the printer (P114), and this homing control operation is terminated.
  If the value of the retry counter is not 0, in order to continue the retry, 0.05V which is a voltage value to be added every time retry is added to the normal value 0.1V of the comparator value (P109). ). Subsequently, the leftward movement process (P110) and the rightward movement process (P111) described above are repeated, and it is determined again whether the error is normal or not in P112. If the error is detected, the retry counter is further updated (- 1) Then, returning to P108, it is checked again whether the value of the retry counter has become zero.
  Each time the retry is repeated, the comparator value is incremented by 0.05 V to increase the leveling ratio at the time of sensor information acquisition, and the comparison determination between the sensor level and the reference level in the leftward movement process and the rightward movement process This time, the previous and last level comparison comparison is facilitated, and the error occurrence rate of the HPM right end detection, peak value detection, and HP stop position analysis is reduced.
[0060]
  [Width detection control]
  After the homing operation control performed immediately after the printer power is turned on, it is confirmed that the medium sensor and the print head moving mechanism are normal, and the analysis of the HP stop position is completed. The medium to be corrected is automatically corrected for skew, and is waiting for an input of a print request signal from the host computer while being sandwiched between the first transport rollers R1 (P4 in FIG. 7). When a print request is input, the carry motor control means 81 drives the carry motor M1 to turn the medium toward the print position.Transport(P5). When the leading edge sensor Sb detects the leading edge of the medium (Y in P6) and when the printing line of the medium is conveyed to the printing position (Y in P7), the rotation of the conveying motor M1 is stopped (P8), and then Then, the control unit 8 calls a program for medium width detection control, which is the second main part of the present invention, from the ROM 91 and starts its execution.
[0061]
  [Width detection control]
  In order to perform medium width detection control, as shown in FIG. 27, the RAM 92 stores all sensor levels output by the medium sensor Sc when the print head H moves to the left of 276 mm, which is its maximum stroke. A two-sensor information storage buffer 925 is provided. FIG. 24 conceptually shows the sensor information storage buffer, and has storage addresses for storing sensor levels for each step as the print head moves in the left direction. Further, the RAM 92 has a MAX value storage buffer 926a and a MIN value storage buffer 926b for storing the MAX level and the MIN level, which are the results when the sensor levels of each step are sequentially compared. Further, as described above, it has the reference level register 921 that stores the reference level (SL) for judging whether the output level of the medium sensor is the higher level or the lower level.
[0062]
  21 is a flowchart showing a main flow for performing medium width detection control, FIG. 22 is a flowchart showing details of width detection interrupt processing in the flow of FIG. 21, and FIG.3FIG. 25 is a flowchart showing details of the medium width measurement result analysis processing in the flow of FIG.this timeFIG. 26 is a conceptual diagram for explaining the principle of medium width detection. FIG. 26 is a diagram for explaining the concept of the center obtained based on the level and the previous level.
[0063]
  When the medium width detection control is started, first, it is checked whether or not the current position of the print head is at HP (P401). If in HP, jump to P403. If the current position of the print head is not in the HP, the carriage motor M3 is driven by the homing operation control described above to move the print head to the HP (stop position) recognized by the previous analysis (P402), and thereafter Move to P403. In P403, the reference level is set as the maximum value (MAX value) of all MAX levels in the MAX value storage buffer 926a. Subsequently, in P404, the reference level is set in the MIN value storage buffer 926b as the minimum value (MIN value) of all MIN levels. ). P403 and P404 may be performed in one step.
[0064]
  Next, 276 mm is set as the print head leftward movement condition (P405). Maximum printable width of this printer (print head etc.Quick transferThe moving stroke) is 250 mm as an example.SpeedIt is set to 276 mm including the enclosure. In the present invention, as shown in FIG.Quick transferHPM is provided in the moving region.
[0065]
  After completing the setting of the print head leftward movement condition, the width detection interrupt process (P406) is started. The width detection interrupt process is performed every time the print head moves one step. First, a step counter C1 is provided which is counted up every time one step is applied to the carriage motor M3, and the current value of the counter is compared with a limit number of steps corresponding to 276 mm (P412). While the current value of the step counter is smaller than the limit step number, the output (sensor level) of the medium sensor is acquired in the second sensor information storage buffer 925 (P413).
[0066]
  Next, the current sensor level is compared with the MAX value (P414), and if the MAX value is larger than the current sensor level, the value is overwritten in the MAX value storage buffer 926a to become a new MAX value ( P415).
  If the current sensor level is equal to or less than the MAX value, the current sensor level is compared with the MIN value (P416). If the current sensor level is less than the MIN value, the value is Is overwritten in the MIN value storage buffer 926b to become a new MIN value (P417). On the other hand, if the current sensor level is equal to or greater than the MIN value, the width detection interrupt process for one step is terminated and the process returns to the main flow of FIG.
[0067]
  In P412, when the step count value is equal to or greater than the limit step number, the carriage motor M3 stops rotating and therefore the print head is stopped.(P418).
[0068]
  As described above, in the width detection interrupt processing, the sensor information is used until the step count value reaches the limit step number every time the print head is moved by one step, that is, until the print head moves to a position beyond the left conveyance guide. When the acquisition is performed and moved by one step, the MAX value and the MIN value of the MAX value storage buffer 926a and the MIN value storage buffer 926b are updated.
  It should be noted that when the sensor information is acquired in P413, the above-described comparator function is activated and the noise information is removed.
[0069]
  [Media position analysis]
  Above width detection interrupt processing(P406)If the result is normal (P407), the next medium position analysis process (P408) is performed. This medium position analysis process is for analyzing the sensor information (sensor level) taken in the second sensor information storage buffer 925 and detecting the right end position and the left end position of the medium sucked up to the print position. is there.
[0070]
  FIG.3These are flowcharts showing the operation contents of the medium position analysis. In this process, a reference level to be used as a reference for discriminating the edge of the medium first is calculated by calculating the following equation.
      Reference level = MAX value− (MAX value−MIN value) / 2
  That is, a value obtained by subtracting 50% of the difference between the MAX value and the MIN value from the MAX value is stored in the reference level register 921 as a reference level.
[0071]
  [Media right edge detection]
  24, the right edge of the medium is detected, and the left edge of the medium is detected in P426 to P433 in FIG. This will be described in detail.
  In the detection of the right end, the sensor information taken in the second sensor information storage buffer 925 is checked in the order in which the number of steps increases from one step (direction D in FIG. 24). This corresponds to checking the sensor level of the medium sensor when the print head H in FIG. 26 moves leftward from the right stop position HP. That is, the one step side of the second sensor information storage buffer 925 of FIG. 24 corresponds to the HP side, and the n step side corresponds to the left conveyance guide 3c side. In P420, P421, and P422, the sensor level (i + n) to be checked is compared with the reference level, and the check is continued until the sensor level becomes larger than the reference level. When the sensor level is equal to or higher than the reference level,this timeBased on the level, calculate the center CL by calculating the following formula:(P423).
    Center =this timeLevel-(this timeLevel-previous level) / 2
  That is,this time50% of the difference between the level and the previous levelthis timeThe value subtracted from the level is the center.
[0072]
  The concept of the center will be described with reference to FIG.FLIs the sensor level in the previous step, ie the previous level,PLIs the sensor level at the current step, i.e.this timeIs a level. The distance between the front and rear two-step media is 1/120 inch (0.2 mm). Now, tentatively the previous levelFLIs smaller than the reference level SL,this timelevelPLIs always greater than the reference level SLthis timeWhen the level becomes higher than the reference level and the step at that time is determined as the medium right end detection position, the reference level SL is fixed,this timelevelPLIs undefined, so the reference level SLthis timelevelPLAn error of a maximum of 0.4 mm will occur between. alwaysthis timeThe same applies to the case where the previous step is adopted as the medium right end detection position when the level becomes higher than the reference level. In order to reduce the influence of such errors, the sensor level to be checked isBaseWhen the quasi-level SL is exceeded, a value of about 50% between the sensor level and the previous level is set as the center (CL), and it is determined whether the center is greater than, equal to, or smaller than the reference level SL. (P424), the right edge detection position of the medium is adjusted according to the result.
[0073]
  That is, when the center CL is larger than the reference level SL, the following equation is calculated and the number of steps as a result of the calculation is stored in the medium right end position data storage unit 928a which is a working data storage area of the RAM (P425). ).
    Media right edge = number of acceleration steps + (this timeNumber of steps to level position-1)
  Here, the number of acceleration steps is the number of steps in the acceleration range of the carriage motor M3 when the print head is moved leftward from the HP. The step counter C1 that operates when the print head moves normally starts counting from the time when the carriage motor M3 starts rotating at a constant speed, but the sensor information is acquired from the beginning of the movement of the print head. In order to match the sensor information with the print head position, it is necessary to add the number of acceleration steps to the step count value.
[0074]
  If the center CL is equal to or smaller than the reference level SL, the following equation is calculated and the number of steps as the calculation result is stored in the medium right end position data storage unit 928a (P426).
    Media right edge = number of acceleration steps +this timeNumber of steps to level position
  The example of FIG. 25 will be described. Since the center CL is larger than the reference level SL, in this case,this timelevelPLWas obtained from the previous step (k)FLThe previous step (k−1) one step before that obtained is set as the medium right end detection position. If the center CL is smaller than the reference level SL illustrated in FIG.this timelevelPLThis time step (k) in which is obtained is set as the medium right end detection position.
[0075]
  [Media left edge detection]
  If the medium right end detection is performed as described above, the medium left end detection process is subsequently performed in P426 to P433. In this case, the sensor information stored in the second sensor information storage buffer 925 is checked from the n step side in one step direction (U direction in FIG. 24). This corresponds to checking the sensor level of the medium sensor when the print head H moves from the left conveyance guide 3c side in FIG. 26 toward the right stop position HP.
  First, in P426 to P428, as in the case of P420 to P422, the sensor level (i + n) to be checked is compared with the reference level, and the check is continued until the sensor level becomes a value larger than the reference level. Is equal to or greater than the reference level, the same as the previous level in P430, as in P423.this timeFind the level center CL. When the sensor level to be checked exceeds the reference level, it is determined whether the center CL obtained in P430 is greater than, equal to, or smaller than the reference level SL (P431), and the center is greater than the reference level. Calculates the following expression, and stores the number of steps as the calculation result in the medium left end position data storage unit 928b which is a working data storage area of the RAM (P432).
    Media left end = number of acceleration steps + (this timeNumber of steps to level position + 1)
  If the center is equal to or smaller than the reference level, the following equation is calculated and the number of steps as the calculation result is stored in the medium left end position data storage unit 928b.(P433).
    Media left end = number of acceleration steps +this timeNumber of steps to level position
[0076]
  If the position of the medium, that is, the position of the right end and the left end of the medium can be analyzed as described above, the process returns to the main flow of FIG. 21, and then the width of the medium is calculated by the following expression. The calculation result is stored in the medium width data storage unit 928c which is a working data storage area of the RAM 92 (P409).
    Medium width = number of steps detected at the left edge of the medium−number of steps detected at the right edge of the medium
[0077]
  In P410 of FIG. 21, it is checked whether or not the previously calculated medium width value conforms to the range of the maximum value and minimum value of the predetermined medium width defined for the printer.
[0078]
  Finally, the current position information of the print head, that is, the current data of the step counter C1 is set in the working data area of the RAM 92, the width detection control process is terminated, and the process returns to the main flow of FIG. (P10).
[0079]
  When a print command is input, printing is performed according to the print command using a known method based on the medium position data (right end position data and left end position data) and medium width data currently stored in the RAM 92 for the medium. While performing the control for setting the position, a predetermined printing process is performed (P11).
  When the printing process is completed, a known conveyance control for returning the medium to the insertion / discharge port 1 is performed (P12), and the medium presence sensor Sa detects the discharge of the medium (Y in P13). A series of processes for the previously inserted medium is terminated.
[0080]
  In the above embodiment, when detecting the right edge of the medium, the sensor information is checked in the direction in which the number of steps increases from the first step corresponding to the leftward movement of the print head from the HP (FIG. 2).4D direction), and when detecting the left edge of the medium, the sensor information is checked in the direction in which the number of steps decreases from the last step corresponding to the rightward movement of the print head from the opposite side of the print head (U direction in the figure). Therefore, for example, even when a feed hole is provided in the middle of the medium in the width direction, or when a tear hole exists, the right and left edges of the medium are detected without being affected, and therefore the width of the medium is detected. There is also a feature that can be performed accurately.
[0081]
  In addition, if the reference level, which is the sensor level judgment standard for media width detection (right edge detection and left edge detection), does not match the media characteristics, it can be adapted to the media characteristics using a software comparator function. Therefore, it is possible to detect a medium with much higher accuracy than in the prior art in which the output level of the optical sensor is determined based on a fixed reference value.
[0082]
  Since the conventional medium insertion position is detected by the skew correction means when it is stopped in front of the print position, even if the medium is skewed before it is transported to the print position, The printing process is performed on the medium without detecting this. Therefore, it has been found that the printing is performed in an inappropriate area after the printing process is completed. However, in the present invention, the presence position of the medium stopped at the printing position is accurately detected, and based on this. Thus, the printing control is performed, so that the reliability regarding the printing area is remarkably improved.
[0083]
  In the above embodiment, HPM is added to the right side of the maximum size of the medium.SpeedThe example in which the HP is provided on the left side has been described, but when the HP is provided on the left side, the HPM is also provided on the left side. In the above embodiment, the print head is moved to the left when performing the homing operation. However, when the HPM is provided on the left side, the print head is moved to the right. Further, the print head is also moved rightward from the HP during medium width detection control. When analyzing the right end and the left end of the medium using the sensor information acquired at the time of detecting the medium width, the analysis may be performed in one direction from one step to n steps. However, when analyzing the sensor information in the direction corresponding to the medium midpoint direction from the outside of the medium for the right end analysis and the left end analysis, respectively, the analysis errors due to the feed holes, tear holes, etc. provided in the medium as described above are prevented. There are advantages you can do.
[0084]
【The invention's effect】
  As described above, according to the present invention, the print head is moved, the HPM is detected by the medium sensor provided in the print head, the HP is detected by analyzing the sensor level, and thereafter When the print head is moved, the sensor level of the medium sensor is analyzed corresponding to each position from the HP to detect the right and left ends of the medium, and the position detection and width calculation of the medium are performed using the analysis result. As a result, the medium can be inserted at an arbitrary position, the burden on the operator can be remarkably reduced, and the position and width of the medium can be accurately detected to ensure accurate printing processing on the medium. TheAlso, the detection output level of one medium sensor provided in the print head is used to determine whether or not the medium sensor and the print head moving mechanism are normal, to analyze the home position of the print head, and to the right and left edges of the medium. Since each process of detection and medium width detection is performed, the number of sensors installed can be significantly reduced as compared with the prior art, so that the printer configuration can be simplified and the cost can be reduced.
[0085]
  Claims3According to the invention, the medium inserted at an arbitrary position is sent to the printing position after the skew is reliably corrected, and position detection and width detection are performed using the medium sensor provided in the print head. Therefore, in a printer that can be inserted at an arbitrary position, the reliability of the printing process for an appropriate print area of the medium is further improved.
[Brief description of the drawings]
FIG. 1 is a schematic side view showing a main part of a printer.
FIG. 2 is a side view of a main part showing a pinch roller pressing force adjusting means which is one component of a skew correction mechanism.
FIG. 3 is a side view of a main part showing a skew correction stopper lifting / lowering means which is another component of the skew correction mechanism.
FIG. 4 is a plan view showing a part of the stopper lifting / lowering means.
FIG. 5 is a plan view showing the principle of medium skew correction.
FIG. 6 is a block diagram showing an example of means for realizing main functions of the printer of the present invention.
FIG. 7 is a flowchart showing the overall operation of the printer.
FIG. 8 is a flowchart showing details of medium skew correction control in step P3 of FIG. 7;
FIG. 9 is a plan view of a main part showing a positional relationship between a medium sensor Sc provided in the print head H and an HPM.
FIG. 10 is an explanatory diagram showing a change state of the sensor level when HPM is detected by the medium sensor Sc.
FIG. 11 is a flowchart of a homing operation.
12 is a flowchart showing details of a leftward movement process in the flowchart of FIG. 11;
13 is a summary flowchart schematically showing a main operation flow of the rightward movement process in the flowchart of FIG. 11;
FIG. 14 is a flowchart showing a part (1/4) of the details of the rightward movement process in the flowchart of FIG. 11;
FIG. 15 is a flowchart showing a part (2/4) of the rightward movement process.
FIG. 16 is a flowchart showing a part (3/4) of the rightward movement process.
FIG. 17 is a flowchart showing a part (4/4) of the rightward movement process.
FIG. 18 is a diagram illustrating the principle of HPM right edge detection.
FIG. 19 is a diagram for explaining the principle of peak value detection.
FIG. 20 is a diagram for explaining the principle of peak intermediate value calculation.
FIG. 21 is a flowchart of medium width detection control.
FIG. 22 is a flowchart showing details of width detection interrupt processing in the flow of FIG. 21;
FIG. 23 is a diagram conceptually showing a second sensor information storage buffer.
FIG. 24 is a flowchart showing details of a medium width measurement result analysis process in the flow of FIG.
FIG. 25this timeExplanatory drawing about the concept of the center calculated | required based on a level and the last level.
FIG. 26 is a conceptual diagram illustrating the principle of medium width detection.
FIG. 27 is a block diagram showing an example of a storage hierarchical structure of a RAM.
[Explanation of symbols]
In FIG.
  4 Transport means
  M1 transport motor
  R1 to R3 transport rollers
  pr1 pinch roller
  dr1 drive roller
1 and 2
  5 Pinch roller pressing force adjusting means
In FIG.
  7 Stopper lifting / lowering means
  70 Stopper
  S1 to S3 ... Skew check sensor
  PM medium
9 and 10
  HPM print head home position detection marker
  STL stop position

Claims (4)

The print head is provided with one medium sensor composed of a light reflection sensor for detecting the medium present at the print position, and the light reflectance is substantially equal to the medium detected by the medium sensor at or near the platen. A home position detection marker having
In the initialization operation performed immediately after the power is turned on, every time the print head is moved in a predetermined direction by one step, the detection output level obtained from the medium sensor is successively three and every time one step is moved. The detection output level stored in the buffer memory is sequentially compared with a reference level stored in advance, the detection output level is lower than the reference level, and the detection output level A process for determining whether or not the medium sensor and the print head moving mechanism are normal based on whether or not the number of times that the current detection output level is equal to the previous detection output level is equal to or greater than a predetermined number , and sequentially stored in the buffer memory this detection output level, by comparing the previous detection output level and the second previous detection output level, the home when a predetermined condition is satisfied Detects Jishon detection marker, we perform homing operation control including the process of memorize by analyzing the home position of the print head based on the detected home position detection marker,
The medium inserted into the printer after the homing operation control is conveyed to a printing position, and then the print head is moved from the home position in a predetermined direction, and each time the print head is moved by one step in the predetermined direction, The sensor information acquisition process for acquiring and storing the detection output level from the medium sensor and the stored current detection output level, the previous detection output level, and the previous detection output level are sequentially compared, and when the predetermined condition is satisfied Medium width calculation for calculating the width of the medium based on processing for detecting the right edge and the left edge of the medium and the number of steps when the print head is moved from the home position to the medium right edge detection position and the medium left edge detection position. and processing, the right end position of the medium, the medium width detection control including the process of storing the left end position and the medium width performed
A printer control method, wherein, when a print command is input, print processing control is performed based on the stored right end position, left end position and medium width of the medium. When processing to detect the right edge of the medium, the stored detection output level is checked from the home position side to the left, and when processing to detect the left edge of the medium, the stored detection output level is opposite to the home position. 2. The printer control method according to claim 1 , wherein the printer is checked in the right direction. An automatic skew correction mechanism for correcting the skew of the inserted medium is provided in the vicinity of the conveyance roller closest to the medium insertion / discharge port of the printer, and the skew of the medium inserted into the printer after the homing operation is determined by the automatic skew correction mechanism. after straightening, the control method of the printer according to claim 1 or 2, characterized in that conveyed to the printing position. In a printer that prints on a predetermined area of a medium supported by the platen by a print head moved in the longitudinal direction of the platen,
The print head is provided with a medium sensor composed of a light reflection type sensor for detecting a medium present at the printing position, and has a light reflectance substantially equal to the medium detected by the medium sensor at or near the platen. Provided with a home position detection marker having
The storage unit includes a reference level register for storing a reference level for determining the magnitude of the detection output level of the medium sensor, and three consecutive pieces sequentially acquired from the medium sensor each time the print head moves one step. Sensor information storage buffer that stores the detection output level of minutes (previous level, previous level, and current level), and data storage that stores the right end position, left end position, and medium width data of the medium acquired by the medium width detection described later With
The control unit includes a homing operation control unit that determines whether the medium sensor and the print head moving mechanism are normal immediately after power-on, a conveyance control unit that conveys the medium inserted into the platen to a predetermined position of the platen, Carriage motor control means for moving the print head in the longitudinal direction of the platen, sensor information acquisition means for acquiring the detection output level from the medium sensor, and each detection output level stored in the sensor information storage buffer memory Position detection means for detecting the right and left edges of the medium, medium width detection means for detecting the width of the medium from the number of steps required for the print head to move from the right edge detection position to the left edge detection position, and Printing control means for printing in a predetermined print area for print data input based on right edge / width detection;
The homing operation control means has three consecutive detection output levels obtained from the medium sensor every time the print head is moved one step in a predetermined direction during an initialization operation performed immediately after power-on, and Each time it moves one step, it is sequentially stored in the buffer memory, and the detected output level stored in the buffer memory is sequentially compared with a pre-stored reference level so that the detected output level is lower than the reference level, and Determining whether or not the medium sensor and the print head moving mechanism are normal depending on whether or not the number of times the current detection output level is equal to the previous detection output level among the detection output levels is equal to or greater than a predetermined number; The current detection output level, the previous detection output level and the previous detection output level stored sequentially in the buffer memory are compared, and Are those conditions are satisfied when said detecting a home position sensing marker, performs a process of storing and analyzing the home position of the print head based on the detected home position detection marker,
The medium width detecting means conveys the medium inserted into the printer after the homing operation control to a printing position, and then moves the print head from the home position in a predetermined direction and moves the print head in a predetermined direction. The sensor information acquisition process for acquiring and storing the detection output level from the medium sensor every time the step moves, and the stored current detection output level, the previous detection output level, and the previous detection output level are sequentially compared to obtain a predetermined value. The right edge and the left edge of the medium when the above condition is satisfied, and the number of steps when the print head is moved from the home position to the medium right edge detection position and the medium left edge detection position. A medium width calculation process for calculating a width, and a process for storing a right end position, a left end position, and a medium width of the medium. It performs a body width detection control,
Printer characterized by.

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