JP2007185812A - Printer and method of detecting conveyance abnormality of printing medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a technique whereby a conveyance abnormality can be precisely detected in a short time without a margin prepared for a magnetic sensor. <P>SOLUTION: The printer includes an ink cassette which sends out an ink carrier, a printing head which transfers ink onto a printing medium from the ink carrier by applying heat according to printing data, a magnetic line of force generating means which is installed in the ink cassette and generates magnetic lines of force when the ink carrier rotates, a magnetism information detecting means which detects magnetism information of the magnetic lines of force, a current detecting means which detects a current value for driving a conveyance means that conveys the printing medium, and a judging means which judges whether the conveyance abnormality of the printing medium by the conveyance means takes place by using the magnetism information detected by the magnetism information detecting means and the current value detected by the current value detecting means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for detecting in a short time a conveyance error of a print medium that occurs during printing.

In a thermal transfer printer that transfers ink from an ink ribbon to a print medium using a thermal head, it is possible to detect an error (hereinafter also referred to as “jam”) in which the print medium cannot be conveyed due to clogging in the conveyance mechanism. It is configured as follows. The error detection is performed when, for example, the number of pulses per unit time of rotation of the ink ribbon core is measured using an ink ribbon cassette to which magnetic information is added and a magnetic sensor, and the current value of the measured number of pulses is greater than the previous value. Jam is determined (see, for example, Patent Document 1).
JP 2003-211801 A

  However, in the method of measuring the number of pulses per unit time that the ink ribbon core rotates as described above and comparing the previous value with the current value, a magnetic sensor is used depending on the size of the slip being conveyed and the size of the magnet attached to the ink ribbon cassette. There is a difference in the number of pulses read by. For this reason, some margin is required in consideration of variations.

  If a large margin is set, it takes time until a jam is detected. As a result, the jam is deteriorated, and the subsequent jam processing operation is time-consuming. In the worst case, the jam processing operation cannot be performed or the device itself is broken. If the margin is set to be small, the time until a jam is detected is shortened, but it is erroneously determined as a jam in spite of the normal state, and normal operation is hindered.

  The present invention has been made in view of the above problems, and an object of the present invention is to realize a technique that can accurately detect a conveyance abnormality in a short time without setting a margin in a magnetic sensor.

  In order to solve the above-described problems and achieve the object, a printing apparatus according to the present invention includes an ink cassette that sends out an ink carrier, and applies heat according to print data from the ink carrier to a print medium. A print head for transferring ink; a magnetic force line generating means provided in the ink cassette for generating magnetic lines of force by rotating the ink carrier; a magnetic information detecting means for detecting magnetic information of the magnetic lines; and the print medium Printing by the conveying means using the current detecting means for detecting the current value for driving the conveying means for conveying the sheet, the magnetic information detected by the magnetic information detecting means, and the current value detected by the current detecting means. Determining means for determining whether a medium conveyance abnormality has occurred.

  According to the present invention, there is also provided a printing medium conveyance abnormality detection method, an ink cassette for sending out an ink carrier, a print head for transferring ink from the ink carrier onto a print medium by applying heat according to print data, and A method of detecting abnormalities in the conveyance of a print medium in a printing apparatus, comprising: a magnetic line of force that is provided in the ink cassette and generates a line of magnetic force by rotating the ink carrier; and detects magnetic information of the line of magnetic force A magnetic information detecting step; a current detecting step for detecting a current value for driving a conveying means for conveying the print medium; and the magnetic information detected in the magnetic information detecting step and the current detecting step. A determination step of determining whether or not a conveyance abnormality of the print medium by the conveyance unit has occurred.

  According to the present invention, it is possible to accurately detect a conveyance abnormality in a short time without setting a margin in the magnetic sensor.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  The following embodiments are examples as means for realizing the present invention, and should be appropriately modified or changed depending on the configuration of the apparatus to which the present invention is applied and various conditions without departing from the spirit of the present invention. The present invention is not limited to the following embodiment.

  The present invention can also be achieved by storing a software program for realizing a conveyance abnormality detection function, which will be described later, in a storage medium, reading the program code from the storage medium, and executing the apparatus constituting the system. Needless to say. That is, the present invention can also be applied to a program for causing a computer to execute a conveyance abnormality detection flow described later, a recording medium for storing the program, and the like.

[Description of device configuration]
FIG. 1 is a schematic diagram of a printer according to an embodiment of the present invention.

  As shown in FIG. 1, the printer 1 of the present embodiment includes a thermal head 4 that applies heat according to print data to sublimate ink from an ink ribbon 9 onto a tape-like or tube-like print medium 8. This is a thermal transfer printer. The print medium 8 is mounted on the cassette housing portion 7 in a tape-like or tube-like manner.

  In the printer 1, the thermal head 4 presses the ink ribbon 9 against the print medium 8 on the outer peripheral surface of the platen roller 2 rotating in the direction of arrow A, and the ink corresponding to the print data is transferred from the ink ribbon 9 to the print medium 8. Thus, an image is formed (printed).

  An ink ribbon cassette 30 having cylindrical ribbon cores 11 and 12 around which an ink ribbon 9 having a predetermined width (a length in a direction perpendicular to the paper surface in FIG. 1) is wound is attached to and detached from the thermal transfer type printer 1. Can be installed freely.

  The ribbon cores 11 and 12 include a sending ribbon core 11 in which an unused ink ribbon is wound and sent out, and a winding ribbon core 12 that winds up a used ink ribbon sent out from the sending ribbon core 11.

  The printer 1 conveys the print medium 8 sandwiched between the platen roller 2 and the driven roller 3 at a constant conveyance speed by rotating the platen roller 2 at a constant rotation number when printing an image on the print medium 8. To do. Further, the printer 1 causes the ink ribbon 9 to be sent out from the sending ribbon core 11 at a constant transport speed.

  The print medium 8 is supplied into the printer 1 from the direction of arrow B and discharged in the direction of arrow C. The print medium 8 supplied from the arrow B direction is sandwiched between the transport roller 5 and the driven roller 6 and transported. The driven roller 6 is configured to move in conjunction with opening and closing of a cover (not shown). That is, when the cover is opened, the driven roller 6 moves from the position indicated by the solid line to the position indicated by the dotted line and moves away from the conveying roller 5, so that the print medium 8 can be easily inserted and removed. On the other hand, when the cover is closed, the driven roller 6 moves to a position where the conveying roller 5 is pressed, and the print medium 8 is pinched between the conveying roller 5 and reliably conveyed.

  The print medium 8 on which image formation has been completed is cut at an appropriate length by the cutter 20 and the cutter receiving surface 22 and discharged in the direction of arrow C.

  Examples of the print medium 8 include a label tape, a flat tube, and a 4 mm ID (index), and these are wound and stored in a dedicated cassette (not shown).

  The sending ribbon core 11 of the ink ribbon cassette 30 generates magnetic lines of force, and the printer 1 is provided with a magnetic sensor 10 for detecting the magnetic lines of force. The magnetic sensor 10 detects the lines of magnetic force only when the direction of the lines of magnetic force matches a predetermined direction. The magnetic sensor 10 is disposed in the axial center portion surrounded by the inner peripheral surface of the hollow ribbon-shaped feeding ribbon core 11 with the ink ribbon cassette 30 mounted in the printer 1.

  When the ink ribbon cassette 30 is mounted on the printer 1, a rotation shaft (not shown) is fitted inside the sending ribbon core 11 and the winding ribbon core 12 (space surrounded by the inner peripheral surface). As a result, the sending ribbon core 11 and the winding ribbon core 12 rotate at a predetermined rotational speed.

  In addition, the magnetic sensor 10 does not rotate because it is attached to a fixed shaft different from the rotating shaft.

  The feeding ribbon core 11 has a cylindrical shape as described above, and generates magnetic lines of force from a certain portion of the inner peripheral surface (not shown) toward the opposite portion (not shown) opposite to the certain portion. Then, magnetic force lines are generated in the sending ribbon core 11 such that the direction (polarity) of the magnetic force lines detected by the magnetic sensor 10 is reversed every half rotation after the sending ribbon core 11 starts rotating.

[Explanation of control block]
FIG. 2 is a block diagram showing the electrical configuration of the entire printer of this embodiment.

  As shown in FIG. 2, reference numeral 41 denotes a CPU that is configured by a microprocessor or the like and serves as a control unit that controls the entire printer 1. Reference numeral 42 denotes an LCD as a display unit for displaying the operation state of the printer 1 and the like. Reference numeral 43 denotes an LCD controller that drives the LCD 42 by a display control signal from the CPU 41. An operation unit 44 includes operation switches and the like. A RAM 45 temporarily records print data and the like and is used as a work area when the CPU 41 executes a control program and the like. A ROM 46 stores a control program executed by the CPU 41, a conveyance abnormality processing program described later, and the like. A character generator 47 generates a character pattern in accordance with a character code expressed in accordance with a code system such as JIS code or ASCII code. A thermal head control circuit 48 generates heat by applying a voltage to each heating element of the thermal head 4 in accordance with print data. Reference numeral 49 denotes a transport motor that rotationally drives the transport roller 5. Reference numeral 50 denotes a driver that drives the conveyance motor 49 in accordance with the drive signal. A motor control circuit 51 outputs a drive signal to the driver 50. A cutter motor 52 drives the cutter 20. A driver 53 drives the cutter motor 52 in accordance with the drive signal. A motor control circuit 54 outputs a drive signal to the driver 53. Reference numeral 55 denotes various sensors including the magnetic sensor 10.

[Description of print medium conveyance abnormality detection processing]
Next, print medium conveyance abnormality detection processing by the printer of this embodiment will be described.

  FIG. 3 is a block diagram for realizing print medium conveyance abnormality detection processing in the printer of this embodiment. The same components as those in FIG. 2 are denoted by the same reference numerals. FIG. 4 is a flowchart showing a print medium conveyance abnormality detection process.

  As shown in FIG. 3, 61 is a pulse generator that generates pulses at regular time intervals. Reference numeral 62 denotes a time measuring device that measures the time until the direction of the magnetic lines of force detected by the magnetic sensor 10 is reversed. A pulse counter 63 counts pulses generated by the pulse generator 61 within the time measured by the time measuring device 62. Since the magnetic field lines detected by the magnetic sensor 10 reverse in polarity every half rotation after the sending ribbon core 11 starts to rotate, the pulse counter 63 counts the number of pulses until the sending ribbon core 11 makes a half rotation. Will be counted. Reference numeral 64 denotes a memory for storing the number of pulses 65 counted by the pulse counter 63. The display unit 42 displays an error message. The driver 50 outputs a current value for driving the transport motor 49 to the CPU 41.

  The pulse generator 61, the time measuring device 62, the pulse counter 63, and the transport motor 49 are built in the housing of the printer 1.

  As an example of the number of pulses generated by the pulse generator 61 at regular time intervals, for example, the sending ribbon core 11 in a state where the ink ribbon 9 (see FIG. 1) is wound to the maximum (the ink ribbon 9 is not used). 3000 pulses generated during the time of one rotation.

  Each time the magnetic sensor 10 detects a line of magnetic force, a detection signal is sent from the time measuring device 62 to the CPU 41, and the CPU 41 drives the pulse counter 63 based on this detection signal. The current value of the transport motor 49 is also sent from the driver 50 to the CPU 41, and the current value is A / D converted by the CPU 41 and recorded as digital data.

  Next, a print medium conveyance abnormality detection process will be described with reference to FIG.

  The flow in FIG. 4 is started when the printer 1 is turned on, the CPU 41 is activated, and the transport motor 49 and the delivery ribbon core 11 rotate. When the printer 1 is turned on, the pulse generator 61, the time measuring device 62, the pulse counter 63, the magnetic sensor 10 and the like start operating.

  In FIG. 4, the CPU 41 counts the number of pulses by the pulse counter 63 for each time until the sending ribbon core 11 makes a half rotation while the direction of the magnetic force lines detected by the magnetic sensor 10 has not changed (S11 to S11). S13). In addition, the CPU 41 acquires the current value of the transport motor 49 from the driver 50.

  Next, the CPU 41 determines whether or not the number of pulses counted by the pulse counter 63 exceeds a predetermined number of pulses (for example, 1500 pulses) (S14). When the number of pulses exceeds the predetermined number of pulses, the CPU 41 determines whether or not the current value after A / D conversion of the transport motor 49 is equal to or greater than a predetermined threshold (S15).

  If the current value is equal to or greater than the predetermined threshold value, it is determined that a jam error has occurred (S22), the transport motor 49 is stopped (S17), and a message indicating a jam error is displayed on the display unit 42 (S18). If the current value is less than the predetermined threshold, it is determined that the error is other than a jam (S15), the transport motor 49 is stopped (S17), and a message indicating an error other than a jam is displayed on the display unit 42 (S18). .

  On the other hand, if the number of pulses is less than the predetermined pulse in S14 and the direction of the lines of magnetic force has changed (NO in S12), the feeding ribbon core 11 rotates normally, and the ink ribbon 9 is gradually sent out to rotate the ribbon core 11. It is thought that the speed is increasing. Therefore, the CPU 41 determines whether or not the delivery ribbon core 11 has made one rotation after starting rotation (S19). Whether the feeding ribbon core 11 has made one rotation is determined by whether or not the direction of the magnetic force lines detected by the magnetic sensor 10 has changed and then returned to the original direction.

  If the rotation is not performed once in S19, the previous pulse number recorded in the memory 64 is not initialized, and the count of the current pulse number is continued.

  On the other hand, when it is determined in S19 that the sending ribbon core 11 has made one rotation after starting rotation, the CPU 41 counts the number of pulses counted in the time until the sending ribbon core 11 makes a half rotation (the previous number of pulses). ) And the number of pulses counted in the time from the half rotation until the half rotation (the current pulse number) is compared (S20).

  As a result of the comparison, when the current pulse number exceeds the previous pulse number (previous pulse number <current pulse number), the CPU 41 determines that the current value after A / D conversion of the carry motor 49 is predetermined. It is determined whether or not the threshold value is exceeded (S21). FIGS. 5 and 6 exemplify the current value at normal time and the current value at jam time, respectively, and the current value threshold value at the time of jam error determination is determined by experimentally obtaining these current values.

  If the current value is equal to or greater than the predetermined threshold value, it is determined that a jam error has occurred (S22), the transport motor 49 is stopped (S17), and an error message is displayed on the display unit 42 (S18). If the current value is less than the predetermined threshold, the current pulse number is recorded in the memory 64 as the previous pulse number (S23), and the pulse counter 63 is initialized (S24).

  According to the above embodiment, the time (number of pulses) during the half rotation of the sending ribbon core 11 is counted, the current number of pulses exceeds the previous number of pulses before half rotation, and When the current value is equal to or greater than a predetermined threshold, it is determined that a jam error has occurred. Thus, jam detection can be performed with high accuracy in a short time without setting a necessary margin with a magnetic sensor as in the prior art.

  Further, jam detection can be performed if the sending ribbon core 11 is rotated at least once, so that jam detection can be performed in a short time after the occurrence of the jam, and the subsequent jam processing operation can be facilitated.

  Further, when the current value to the conveyance motor 49 is monitored, since the CPU 41 takes in the current value of the driver 50 and performs A / D conversion, a dedicated circuit is not necessary and the cost can be reduced.

1 is a schematic diagram of a printer according to an embodiment of the present invention. 2 is a block diagram illustrating an electrical configuration of the entire printer of the present embodiment. FIG. FIG. 4 is a block diagram for realizing a print medium conveyance abnormality detection process in the printer of the present embodiment. 10 is a flowchart illustrating a print medium conveyance abnormality detection process. It is a figure which illustrates the electric current value at the time of normal. It is a figure which illustrates the electric current value at the time of jam.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer 2 Platen roller 3 Driven roller 4 Thermal head 5 Carrying roller 6 Driven roller 7 Cassette accommodating part 8 Print medium 9 Ink ribbon 10 Magnetic sensor 11 Ribbon core 12 for take-up Ribbon core 20 Cutter 22 Cutter receiving surface 30 Ink ribbon cassette 41 CPU
42 Display (LCD)
43 LCD controller 44 Operation unit 45 RAM
46 ROM
47 Character generator 48 Thermal head control circuit 49 Conveyance motor 50 Driver 51 Motor control circuit 52 Cutter motor 53 Driver 54 Motor control circuit 55 Sensors 61 Pulse generator 62 Time measuring device 63 Pulse counter 64 Memory 65 Number of previous pulses

Claims (14)

An ink cassette for feeding out the ink carrier;
A print head that applies heat according to print data to transfer ink from the ink carrier onto a print medium;
Magnetic line of force generating means that is provided in the ink cassette and generates a line of magnetic force when the ink carrier rotates.
Magnetic information detecting means for detecting magnetic information of the magnetic field lines;
Current detecting means for detecting a current value for driving a conveying means for conveying the print medium;
And determining means for determining whether or not a conveyance abnormality of the print medium by the conveying means has occurred using the magnetic information detected by the magnetic information detecting means and the current value detected by the current detecting means. A printing device. The magnetic information includes count information for counting the direction of the magnetic field lines and the time for which the direction of the magnetic field lines changes,
The printing apparatus according to claim 1, wherein the determination unit determines that a conveyance abnormality of the print medium has occurred when the count information exceeds a comparison value and the current value is equal to or greater than a reference value. . The magnetic information includes count information for counting the direction of the magnetic lines of force and the time when the direction of the magnetic lines of force changes,
2. The determination unit according to claim 1, wherein when the count information is equal to or smaller than a comparison value and the current value is equal to or greater than a reference value, it is determined that an abnormality different from the conveyance abnormality of the print medium has occurred. The printing apparatus according to 2. The magnetic information includes count information for counting the direction of the magnetic lines of force and the time when the direction of the magnetic lines of force changes,
2. The determination unit according to claim 1, wherein when the count information exceeds a comparison value and the current value is less than a reference value, it is determined that an abnormality different from a conveyance abnormality of the print medium has occurred. The printing apparatus according to 2. A counter that counts the time when the direction of the magnetic lines of force changes, and a memory that records count information immediately before the direction of the lines of magnetic force changes,
The determination unit compares the previous count information recorded in the memory with the latest current count information as the comparison value, and determines whether or not the current count information exceeds the previous count information. The printing apparatus according to any one of 2 to 4.   6. The printing according to claim 2, further comprising: a display unit that displays a message to that effect when the determination unit determines that a conveyance abnormality of the print medium has occurred. apparatus. An ink cassette for delivering an ink carrier; a print head for applying heat according to print data to transfer ink from the ink carrier onto a print medium; and the ink cassette, the ink carrier rotating. A method of detecting abnormalities in conveying a print medium in a printing apparatus comprising:
A magnetic information detection step of detecting magnetic information of the magnetic field lines;
A current detection step of detecting a current value for driving a transport means for transporting the print medium;
A determination step of determining whether or not a conveyance abnormality of the print medium by the conveyance unit has occurred using the magnetic information detected in the magnetic information detection step and the current value detected in the current detection step. A method characterized by: The magnetic information includes count information for counting the direction of the magnetic field lines and the time for which the direction of the magnetic field lines changes,
The method according to claim 7, wherein in the determination step, it is determined that a conveyance abnormality of the print medium has occurred when the count information exceeds a comparison value and the current value is equal to or greater than a reference value. The magnetic information includes count information for counting the direction of the magnetic lines of force and the time when the direction of the magnetic lines of force changes,
8. The determination step according to claim 7, wherein when the count information is equal to or less than a comparison value and the current value is equal to or greater than a reference value, it is determined that an abnormality different from the print medium conveyance abnormality has occurred. 9. The method according to 8. The magnetic information includes count information for counting the direction of the magnetic field lines and the time for which the direction of the magnetic field lines changes,
8. The determination step according to claim 7, wherein when the count information exceeds a comparison value and the current value is less than a reference value, it is determined that an abnormality different from a conveyance abnormality of the print medium has occurred. 9. The method according to 8. Counting the time when the direction of the lines of magnetic force changes, and further comprising the step of recording the count information immediately before the direction of the lines of magnetic force changes in a memory,
The determination step includes comparing the previous count information recorded in the memory with the latest current count information as the comparison value, and determining whether or not the current count information exceeds the previous count information. The method according to any one of 8 to 10.   The method according to any one of claims 8 to 11, further comprising a step of displaying a message to that effect when it is determined in the determination step that a conveyance abnormality of the print medium has occurred. .   A program for causing a computer of a printing apparatus to execute the method according to any one of claims 7 to 12.   A computer-readable storage medium storing the program according to claim 13.

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