JP2006305986A - Paper feeding device and method for recording paper roll - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a vibration detecting sensor from making an error in detection when paper is fed by detecting the distal end of a recording paper on the outer periphery of a recording paper roll by using a distal end detecting sensor such as the vibration detecting sensor. <P>SOLUTION: A paper feeding section 14 of a color thermal printer is constituted of a holding member (not shown in the figure), a paper feeding roller 31, a separating plate 37, the vibration detecting sensor 40 provided on the separating plate 37, and a marker detecting sensor 44. In this case, the holding member holds the recording paper roll 13 for which the recording paper 11 is rolled up into a roll shape around a rolling core 12. The paper feeding roller 31 is press-contacted to the outer peripheral surface of the recording paper roll 13. The separating plate 37 separates the distal end of the recording paper 11 from the outer periphery of the recording paper roll. The marker detecting sensor 44 detects a marker 43 which is placed on the side surface of the rolling core 12. The recording paper roll 13 is reversed before the paper feeding is performed by normally rotating the recording paper roll 13. The marker 43 is detected by the marker detecting sensor 44, and one rotation time T of the recording paper roll 13 is calculated. After T+α(error) has passed since the detection of the vibration by the vibration detecting sensor 40, if the vibration is detected again, the detected position is judged to be the distal end of the recording paper 11. Thus, the vibration detecting sensor 40 is prevented from making an error in detection. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a paper feeding apparatus and method using a recording paper roll such as thermal recording paper or photographic paper.

  A color thermal printer, a photographic printer, and the like that use a recording paper roll obtained by winding a recording paper such as a long thermal recording paper or photographic paper into a roll are well known. The recording paper roll is housed in the paper feed unit of the printer, and is rotated forward and backward by a paper feed roller or the like pressed against the outer periphery thereof.

  When the recording paper roll is rotated forward, the recording paper is fed from the paper feeding unit to the printing unit, and printing processing is performed. The recording paper that has been printed is cut to a predetermined size and discharged outside the printer. Thereafter, if the next print instruction is not given even after a predetermined time has elapsed, the recording paper roll is reversed. As a result, the unrecorded portion of the recording paper that has not been printed is taken up by the recording paper roll, and the influence of light and humidity is prevented.

  When a print instruction is issued again, the recording paper roll is rotated forward. At this time, the separation plate contacts the outer peripheral surface of the recording paper roll with elasticity. The separation plate abuts against the leading end of the recording paper when the recording paper roll is rotated forward, and separates the leading end from the recording roll. The leading edge of the separated recording paper is guided to the printing unit along a conveyance guide or the like, and the recording paper is fed to the printing unit.

  At this time, if the time from when the recording paper roll is normally rotated until the leading edge of the recording paper comes into contact with the separation plate is long, the recording paper is wound and loosened. As a result, the leading edge of the recording paper may be separated at a place other than abutting against the separation plate, and the recording paper may not be fed successfully. In particular, heat-sensitive recording paper, photographic paper, and the like are prone to loosening because they are thick and stiff. For this reason, the recording paper roll is usually rotated in the reverse direction, the leading edge of the recording paper on the outer periphery thereof is detected by the leading edge detection sensor, and the recording paper roll is normally rotated after the leading edge of the recording paper has passed the separation plate. It is.

As such a tip detection sensor, as described in Patent Document 1, a vibration detection sensor is usually used. This vibration detection sensor is attached to the separation plate. As described above, the separation plate is in elastic contact with the outer peripheral surface of the recording paper roll. Accordingly, when the leading edge of the recording paper passes through the separation plate when the recording paper roll is reversed, the leading edge of the separation plate is detached from the leading edge of the recording paper. Since the separation plate vibrates due to the impact at this time, the leading edge of the recording paper can be detected by detecting the vibration of the separation plate with the vibration detection sensor. Thus, the recording paper roll can be rotated forward after the leading edge of the recording paper has passed through the separation plate, and the leading edge of the recording paper can be separated from the recording paper roll by the separation plate.
JP 2002-308525 A (pages 4-5)

  By the way, if a vibration caused by an impact other than an impact due to the passage of the leading edge of the recording paper occurs on the separation plate, the vibration detection sensor detects this vibration and causes an erroneous detection. Further, when the recording paper roll is reversed, the separation plate vibrates slightly even when the leading edge of the recording paper does not pass. In this case as well, there is a possibility that the vibration detection sensor similarly causes erroneous detection. As described above, when the vibration detection sensor makes a false detection, the timing for normal rotation of the recording paper roll is deviated, and the leading edge of the recording paper cannot be separated. The same problem occurs when the leading edge of the recording paper is optically detected.

  The present invention has been made to solve the above-mentioned problems, and reliably feeds the paper when the leading edge of the recording paper roll is detected and fed using a leading edge detection sensor such as a vibration detection sensor. An object of the present invention is to provide a recording paper roll feeding apparatus and method that can be used.

  According to the present invention, a recording paper roll, in which a long recording paper is wound in a roll shape around a winding core, is rotatably stored, and the recording paper roll is drawn out from the recording paper roll and fed to a printing unit. In the paper device, the recording paper roll is rotated forward to feed the recording paper in the paper feeding direction, and is rotated reversely to wind the recording paper, and the recording paper roll is rotated forward to feed the paper. A roll rotation control means for controlling the roll rotation means so that the recording paper roll is reversely rotated before detecting the leading edge of the recording paper on the outer periphery of the recording paper roll during the reverse rotation; A leading edge detecting means for outputting a detection signal; and a detection when the leading edge detection signal is output again after the recording paper roll has been rotated once after the leading edge detection signal is output from the leading edge detection means. Characterized in that it comprises a determining means for location between the tip of the recording paper.

  Further, when the tip detection signal is not output again from the tip detection unit, the determination unit determines that the tip detection signal output from the tip detection unit is a false detection.

  Further, it is preferable that a one-rotation time detecting unit for detecting one rotation time of the recording paper roll during the reverse rotation is provided. Further, the one rotation time detecting means includes a marker provided on a side surface of the core, a marker detecting means provided at a position facing the side surface of the core, and detecting the marker; One rotation time calculation means for calculating the one rotation time from the difference between the time when the marker is first detected and the time when the marker is detected next while the recording paper roll is rotating in the reverse direction based on the detection result; It is preferable that it is comprised.

  A separation plate that is in contact with the outer peripheral surface of the recording paper roll and separates the leading end of the recording paper from the recording paper roll when the recording paper roll is rotated forward; The leading edge detection means is preferably a vibration detection sensor that is provided on the separation plate and detects vibration caused by contact between the separation plate and the leading edge of the recording paper.

  In addition, when the determination unit determines that the detected position is the leading edge of the recording paper, the roll rotation control unit controls the roll rotation unit to stop the recording paper roll being reversely rotated. It is preferable to rotate.

  Further, it is preferable that the leading edge of the recording paper separated by the separation plate is conveyed toward the print unit along the separation plate. And a passage detection means for detecting the passage of the recording paper conveyed along the separation plate, and the passage detection means detects the passage of the recording paper even if a predetermined time has elapsed after the recording paper roll is rotated forward. When the passage is not detected, the roll rotation control unit controls the roll rotation unit to stop the normal rotation of the recording paper roll and then reverse the rotation, and during the rotation, the leading end of the recording paper by the leading end detection unit It is preferable that the detection of the tip and the determination of the tip detection signal by the determination unit are performed again.

  In the recording paper roll feeding method of the present invention, the recording paper roll obtained by winding a long recording paper in the form of a roll around a winding core is rotated forward before feeding the recording paper in the paper feeding direction. Reversing the recording paper roll, detecting one rotation time of the recording paper roll during the reverse rotation, detecting the leading edge of the recording paper on the outer periphery of the recording paper roll, and outputting a leading edge detection signal; Only when the recording paper roll is rotated once after the leading edge detection signal is output and then the leading edge detection signal is output again, the detected position is determined as the leading edge of the recording paper, and at the time of the determination, the recording is performed. The reverse rotation of the paper roll is stopped and then rotated forward.

  The recording paper roll feeding device of the present invention rotates the recording paper roll, which is a long recording paper wound in a roll shape, forwardly feeds the recording paper in the paper feeding direction, and reversely winds the recording paper Roll rotation means; roll rotation control means for controlling the roll rotation means so that the recording paper roll is reversed before paper feeding; and the recording paper on the outer periphery of the recording paper roll during the reverse rotation. A leading edge detection means for detecting the leading edge of the recording paper and outputting a leading edge detection signal; and after the leading edge detection signal is output from the leading edge detection means, the leading edge detection signal is output again after one rotation of the recording paper roll. In some cases, there is provided a determining means for determining the detected position as the leading edge of the recording paper, so that erroneous detection by the leading edge detecting means can be prevented and the recording paper can be reliably fed.

  If the tip detection signal is not output again from the tip detection means, the tip detection signal output by the tip detection means is determined to be a false detection. Can prevent false detection.

  Further, the recording paper roll feeding method of the present invention reverses the recording paper roll before rotating the recording paper roll forward and feeding the recording paper in the paper feeding direction. While detecting one rotation time, the leading edge of the recording paper on the outer periphery of the recording paper roll is detected and a leading edge detection signal is output. After the leading edge detection signal is output, the recording paper roll rotates once. Only when the leading edge detection signal is output again after being detected, the detected position is determined to be the leading edge of the recording paper, and at the time of this determination, the reverse rotation of the recording paper roll is stopped and the forward rotation is performed. Therefore, similarly, the recording paper can be reliably fed.

  FIG. 1 is a schematic view of a one-head three-pass color thermal printer (hereinafter simply referred to as a printer) 10 embodying the present invention. The printer 10 is roughly divided into a long color thermal recording paper (hereinafter simply referred to as recording paper) 11 and a paper feeding unit 14 in which a recording paper roll 13 is wound around a winding core 12 in a roll shape. And a printing unit 15 for printing an image on the recording paper 11 fed from the unit 14.

  As is well known, the recording paper 11 has a cyan (C) thermosensitive coloring layer, a magenta (M) thermosensitive coloring layer, and a yellow (Y) thermosensitive coloring layer sequentially provided on a support. The Y thermosensitive coloring layer as the uppermost layer has the highest thermal sensitivity and develops yellow with a small amount of heat energy. The C thermosensitive coloring layer, which is the lowermost layer, has the lowest thermal sensitivity and develops cyan with large heat energy. The Y thermosensitive coloring layer loses its coloring ability when irradiated with near ultraviolet rays of 420 nm. The M thermosensitive coloring layer develops magenta with intermediate thermal energy between the Y thermosensitive coloring layer and the C thermosensitive coloring layer, and loses the coloring ability when irradiated with 365 nm ultraviolet rays. The recording paper 11 may be provided with, for example, a black thermosensitive coloring layer to form a four-layer structure.

  The paper feeding unit 14 is an embodiment of the present invention. As will be described in detail later, the recording paper roll 13 is rotated forward (clockwise in the figure) when a print instruction is issued, and the recording paper 11 is fed in the paper feeding direction. The recording paper 11 is fed to the print unit 15.

  The print unit 15 includes a conveyance roller pair 17, a thermal head 18 and a platen roller 19, an optical fixing device 20, and a cutter 21 in order from the upstream side along the conveyance path of the recording paper 11 fed from the paper supply unit 14. Has been placed.

  The conveyance roller pair 17 includes a feed roller 23 that is rotationally driven by a stepping motor (hereinafter simply referred to as a motor) 16 and a pinch roller 24 that presses against the feed roller 23 and sandwiches the recording paper 11. It is conveyed in the sub-scanning direction orthogonal to the main scanning direction, that is, in the A direction and B direction in the figure.

  The thermal head 18 and the platen roller 19 are arranged so as to sandwich the conveyance path of the recording paper 11. The thermal head 18 is disposed above the conveyance path of the recording paper 11 and includes a heating element array 18a in which a large number of heating elements are arranged in a line along the main scanning direction. Further, the thermal head 18 forms a gap between the press contact position where the heating element array 18a is pressed against the recording paper 11 and the platen roller 19 away from the recording paper 11 by a head moving mechanism (not shown). It is possible to move between the retracted positions. The platen roller 19 is driven and rotated in accordance with the conveyance of the recording paper 11, and stabilizes the contact state between the recording paper 11 and the heating element array 18a.

  The heating element array 18a generates heat based on image data for one line of an image to be printed when the recording paper 11 is conveyed in the B direction by the conveying roller pair 17. Thus, while the recording paper 11 is fed line by line by the conveying roller pair 17, a specific thermosensitive coloring layer in the recording area of the recording paper 11 is colored line by line, and the line image in the main scanning direction is 1 line. It is printed sequentially.

  The optical fixing device 20 is disposed so as to face the recording surface of the recording paper 11. The optical fixing device 20 includes a yellow (Y) fixing lamp 26, a magenta (M) fixing lamp 27, a reflector 28, and the like. The Y fixing lamp 26 emits near ultraviolet rays having an emission peak of 420 nm, and fixes the Y thermosensitive coloring layer of the recording paper 11. The M fixing lamp 27 fixes the M thermosensitive coloring layer by emitting ultraviolet rays of 365 nm.

  The cutter 21 cuts the recording paper 11 on which the C image has been printed into a predetermined print size to form a color print (not shown). The color print is discharged from a discharge port 29 provided on the downstream side of the cutter 21 in the A direction.

  If the next print instruction is not given even after a predetermined time has elapsed after the printing is completed, the paper supply unit 14 rotates the recording paper roll 13 in the reverse direction (counterclockwise in the figure) to wind the recording paper 11 to obtain light and humidity. Prevent the effects of.

  FIG. 2 shows a schematic view of the paper supply unit 14 embodying the present invention. The paper supply unit 14 includes a paper supply roller 31 that is pressed against the outer peripheral surface of the recording paper roll 13, a first shift mechanism 32 that displaces the paper supply roller 31 in accordance with a change in the winding diameter of the recording paper roll 13, and recording. A separation unit 33 that separates the leading end 11a (see FIG. 3) of the recording paper 11 from the outer periphery of the paper roll 13, a second shift mechanism 34 that displaces the separation unit 33 in accordance with a change in the winding diameter of the recording paper roll 13, Although not shown, the storage case includes a storage case that stores the recording paper roll 13 and a roll holding member that is provided in the storage case and rotatably holds the recording paper roll 13.

  The paper feed roller 31 is rotationally driven by the motor 16 in the same manner as the feed roller 23. The paper feed roller 31 rotates the recording paper roll 13 forward to feed the recording paper in the paper feeding direction at the time of paper feeding, and reverses the recording paper roll 13 after printing to turn the recording paper 11 into the recording paper roll 13. Wind up.

  The first shift mechanism 32 is composed of, for example, an arm, a spring, a cam, and the like, and even when the winding diameter of the recording paper roll 13 changes, the paper feed roller 31 is always pressed against the outer peripheral surface thereof. Is displaced. The change in the winding diameter of the recording paper roll 13 can be easily obtained by, for example, counting the number of drive pulses of the motor 16.

  The separation unit 33 is disposed at a position substantially opposite to the separation plate 37 that contacts the outer peripheral surface of the recording paper roll 13, and guides the recording paper 11 fed from the recording paper roll 13 to the printing unit 15. And a guide plate 38. The separation plate 37 is formed of a thin plate such as plastic having elasticity. The separation plate 37 has its leading end elastically in contact with the outer peripheral surface of the recording paper roll 13, and comes into contact with the leading end 11 a of the recording paper 11 when the recording paper roll 13 is rotated forward. Separate from the perimeter of the. The separated leading end 11 a is guided to the printing unit 15 along a conveyance path formed between the separation plate 37 and the guide plate 38, and the recording paper 11 is fed to the printing unit 15.

  Similar to the first shift mechanism 32, the second shift mechanism 34 is also composed of an arm, a spring, a cam, and the like. Then, the second shift mechanism 34 integrally displaces the separation plate 37 and the guide plate 38 according to the change in the winding diameter of the recording paper roll 13. Thereby, when the recording paper roll 13 is rotated forward, the leading end 11 a can be reliably separated from the outer periphery of the recording paper roll 13.

  As described above, the recording paper 11 used in the printer 10 is thick and stiff, so that it is likely to be loosened. Therefore, if the time until the leading edge 11a of the recording paper 11 comes into contact with the separation plate 37 when the recording paper roll 13 is rotated forward is long, the recording paper 11 is wound and loosened. As a result, the front end 11a (see FIG. 3) of the recording paper 11 is separated from the outer periphery of the recording paper roll 13 before being separated by the separation plate 37, and the recording paper 11 may not be fed to the printing unit 15. .

  Therefore, the separation plate 37 is provided with a vibration detection sensor 40 for detecting the leading end 11 a of the recording paper 11 on the outer periphery of the recording paper roll 13. The vibration detection sensor 40 detects the vibration of the separation plate 37 that seems to be caused by the passage of the leading edge 11a of the recording paper 11, and outputs a leading edge detection signal of a level corresponding to the magnitude of the vibration (see FIG. 4). When the separation plate 37 vibrates, the separation plate 37 is deformed or distorted. For example, a piezoelectric element or a strain sensor that detects the deformation or distortion of the separation plate 37 is used as the vibration detection sensor 40.

  As shown in FIG. 3, the leading end of the separation plate 37 is pressed against the outer peripheral surface of the recording paper roll 13 by the second shift mechanism 34. Therefore, the separation plate 37 is in contact with the outer peripheral surface of the recording paper roll 13 in a bent state. Therefore, when the leading end 11a of the recording paper 11 passes the leading end of the separating plate 37 when the recording paper roll 13 is reversed, the leading end of the separating plate 37 is caused by the elastic force of the separating plate 37 or the like. Deviate from. And the separating plate 37 vibrates by the impact at this time.

  At this time, the separation plate 37 vibrates slightly even when the leading end 11 a of the recording paper 11 does not pass through the separation plate 37. For this reason, the vibration detection sensor 40 may detect this vibration and cause erroneous detection. The vibration detection sensor 40 also causes erroneous detection when vibration due to other than the impact caused by the passage of the leading end 11a of the recording paper 11 occurs on the separation plate 37. When such an erroneous detection occurs, the timing for normal rotation of the recording paper roll 13 is shifted, and the leading edge separation work of the leading edge 11a of the recording paper 11 becomes unsuccessful.

  Therefore, in this embodiment, before the vibration detection sensor 40 detects the leading edge 11a of the recording paper 11, the one rotation time (cycle) T of the recording paper roll 13 that is rotating in reverse is obtained in advance. Then, after vibration is detected by the vibration detection sensor 40 and the tip detection signal is output, after approximately the same time as one rotation time T has elapsed, vibration is again detected by the vibration detection sensor 40 and the tip detection signal is regenerated. It is determined whether the previously detected vibration is due to the passage of the leading end 11a of the recording paper 11 or is caused by another cause, that is, a false detection depending on whether or not it is output.

  As shown in FIG. 2, a marker 43 is provided on the side surface of the core 12 of the recording paper roll 13 in order to detect one rotation time T of the recording paper roll 13. A marker detection sensor 44 that detects the marker 43 is provided at a position facing the side surface of the core 12. The marker detection sensor 44 includes, for example, an irradiation unit (not shown) that irradiates the inspection light onto the side surface of the core 12 and a light receiving unit (not shown) that receives the inspection light reflected on the side surface of the core 12. Composed.

  The tip detection signal of the vibration detection sensor 40 and the marker detection signal of the marker detection sensor 44 are input to the overall control unit 46. The overall control unit 46 includes the first shift mechanism 32, the second shift mechanism 34, the vibration detection sensor 40, the marker detection sensor 44, the motor driver 48 that drives the motor 16, the remaining amount of the recording paper 11, and error messages. Are connected to a display monitor 49 for displaying the above, and a passage detection sensor 50 described later in detail. Further, although not shown in the figure, a head driver that drives the heating element 18a of the thermal head 18, a lamp driver that drives the optical fixing device 20, a cutter driver that drives the cutter 21, and the like are connected to the overall control unit 46. The operation of each unit of the printer 10 is controlled by the overall control unit 46.

  The overall control unit 46 includes a motor control unit 52 that controls driving of the motor 16 via a motor driver 48, a one-rotation time calculation unit 53 that calculates one rotation time T of the recording paper roll 13, and a vibration detection sensor 40. A recording paper leading edge determination unit 54, a time counter 55, a memory 57, a retry number counter 59, and the like that determine whether or not the detected vibration is caused by the passage of the leading edge 11a of the recording paper 11 are provided.

  When a print instruction is given, the motor control unit 52 rotates the motor 16 at a constant speed via the motor driver 48 to rotate the paper feed roller 31 in the clockwise direction in the drawing. Thereby, the recording paper roll 13 is reversed at a constant speed. Note that the recording paper roll 13 that has been loosened can be wound up by reversing the recording paper roll 13 before feeding. When the reverse rotation of the recording paper roll 13 is started, the marker 43 is detected by the marker detection sensor 44. The marker detection signal output from the marker detection sensor 44 is input to the one rotation time calculation unit 53 in the overall control unit 46.

The one-rotation time calculation unit 53 resets the counter value of the time counter 55 when the reverse rotation of the recording paper roll 13 is started, and starts measuring time by the time counter 55. Then, the one-rotation time calculation unit 53 reads the timer value t1 of the time counter 55 when the marker 43 is read first (first time) by the marker detection sensor 44. When the marker 43 is read again (second time) by the marker detection sensor 44, the one rotation time calculation unit 53 reads the timer value t2 of the time counter 55 at that time. The one-rotation time calculation unit 53 calculates the difference between the timer value t2 and the timer value t1, so that one rotation time T (= t2) of one rotation of the recording paper roll 13 -T1) is calculated. The calculation result of one rotation time T is input to the recording paper leading edge determination unit 54.

  The recording paper leading edge determination unit 54 reads the timer value of the time counter 55 at this time when the vibration detection sensor 40 detects a vibration that seems to be caused by the passage of the leading edge 11a of the recording paper 11 and outputs a leading edge detection signal. Thus, the data is temporarily stored in the memory 57. At this time, if no vibration is detected after a predetermined time has elapsed, the recording paper leading edge determination unit 54 outputs an error signal to the motor control unit 52. When the error signal is input, the motor control unit 52 stops the rotation of the recording paper roll 13. At the same time, the overall control unit 46 displays an error display on the display monitor 49.

  Based on the timer value of the time counter 55, the recording paper leading edge determination unit 54 detects when the vibration is detected again by the vibration detection sensor 40 and the leading edge detection signal is output again after T + α has elapsed since the vibration was detected. It is determined that the position is the leading edge 11 a of the recording paper 11. Here, α is an error in detection time, and an optimum value obtained in advance through experiments is used.

  When the leading edge detection signal is not output again from the vibration detection sensor 40, the recording paper leading edge determination unit 54 determines that the leading edge detection signal (vibration) is a false detection. Then, the detection work of the leading edge 11a by the vibration detection sensor 40 and the determination work by the recording paper leading edge determination unit 54 are repeatedly performed. At this time, if the next vibration is not detected even after a predetermined time has elapsed, the rotation of the recording paper roll 13 is stopped as described above, and then an error display is displayed on the display monitor 49.

  In addition, when a plurality of vibrations are detected by the vibration detection sensor 40 while the recording paper roll 13 is rotated once, the recording paper leading edge determination unit 54 stores the detection time of each vibration in the memory 57. . Then, the recording paper leading edge determination unit 54 determines each vibration in parallel depending on whether or not it is detected again after T + α has elapsed for each vibration. Specifically, a description will be given with reference to FIG. 4 showing an example of the tip detection signal waveform of the vibration detection sensor 40 when the recording paper roll 13 is reversed.

  As shown in FIG. 4, when the vibration is detected by the vibration detection sensor 40 and the leading edge detection signal P1 is output from the vibration detection sensor 40, the recording paper leading edge determination unit 54 determines when the leading edge detection signal P1 is output. The timer value t3 of the time counter 55 is stored in the memory 57. Next, when the leading edge detection signal P2 is output from the vibration detection sensor 40 before the recording paper roll 13 is rotated once after the leading edge candidate P1 is output, similarly, the timer value t4 of the time counter 55 at that time is stored in the memory. Store in 57.

  The recording paper leading edge determination unit 54 outputs the leading edge detection signal P1 from the vibration detection sensor 40 when the recording paper roll 13 is continuously reversed and the timer value of the time counter 55 reaches t5 when T + α has elapsed from t3. If not, the tip detection signal P1 output previously is determined to be erroneous detection. Then, when the leading edge detection signal P2 is output again when the timer value of the time counter 55 reaches t6 when T + α has elapsed from t4, the recording sheet leading edge determination unit 54 sets the detected position to the leading edge 11a of the recording sheet 11. Is determined. Thus, when a plurality of vibrations are detected, the time required for specifying the position of the leading edge 11a of the recording paper 11 can be shortened by performing individual determinations by so-called parallel processing.

  If it is determined that the vibration detected by the vibration detection sensor 40 is due to the passage of the leading end 11a of the recording paper 11, the motor control unit 52 stops the rotating recording paper roll 13 and then rotates it forward. As a result, after the leading end 11a of the recording paper 11 passes through the separation plate 37, specifically, the recording paper roll 13 can be rotated forward when the leading end 11a is between the separation plate 37 and the paper feed roller 31. The leading end 11 a can be separated from the recording paper roll 13 before the recording paper 11 is wound and loosened. At this time, in this embodiment, the leading end 11a of the recording paper 11 is separated from the recording paper roll 13, and the guide plate 38 is detected to detect whether the recording paper 11 is reliably fed to the printing unit 15. A passage detection sensor 50 is provided.

  The passage detection sensor 50 is an optical sensor composed of, for example, a light emitting element and a light receiving element, and the passage of the recording paper 11 conveyed along a conveyance path formed between the separation plate 37 and the guide plate 38 is detected. To detect. Therefore, when the passage detection sensor 50 detects the passage of the recording paper 11, it is determined that the leading end 11 a of the recording paper 11 is separated from the recording paper roll 13 and the recording paper 11 is reliably fed to the printing unit 15. it can. The detection signal of the passage detection sensor 50 is output to the motor control unit 52 in the overall control unit 46.

  When the passage detection sensor 50 detects the passage of the recording paper 11 within a certain time after the recording paper roll 13 is rotated forward based on the timer value of the time counter 55, the motor control unit 52 detects that the recording paper 11 has been printed. 15 is determined to be reliably fed, and the normal rotation of the recording paper roll 13 is continued.

  If the passage detection sensor 50 does not detect the passage of the recording paper 11 even after a predetermined time has elapsed since the recording paper roll 13 is rotated forward, the motor control unit 52 separates the leading end 11a of the recording paper 11. Judge that it failed. In this case, the motor control unit 52 stops the normal rotation of the recording paper roll 13 and then reverses it again. Then, after the above-described detection / determination operation for the leading end 11a of the recording paper 11 is repeated, the motor control unit 52 rotates the recording paper roll 13 in the normal direction to retry separation of the leading end 11a of the recording paper 11. To do. Thereafter, until the separation of the leading end 11a of the recording paper 11 is confirmed by the passage detection sensor 50, the above-described leading end separation operation (including the detection / determination operation of the leading end 11a) is repeated.

  The number of retries for the tip separation work is counted by a retry number counter 59. When the count number of the retry number counter 59 exceeds a certain value, the motor control unit 52 stops the rotation of the recording paper roll 13. The overall control unit 46 also displays an error display on the display monitor 49.

  As described above, in the present embodiment, the detection position is changed only when the leading edge detection signal is output again after the recording paper roll 13 has made one rotation after the leading edge detection signal is output from the vibration detection sensor 40. Since the leading edge 11a of the recording paper 11 is determined, erroneous detection of the leading edge 11a by the vibration detection sensor 40 can be prevented.

  Next, the operation of the printer 10 of this embodiment will be described using the flowcharts of FIGS. When a print instruction is issued, the motor control unit 52 of the overall control unit 46 rotates the paper feed roller 31 in the clockwise direction in the drawing to reverse the recording paper roll 13 at a constant speed. At the same time, the time value of the time counter 55 and the count number of the retry number counter 59 are reset.

  When the reverse rotation of the recording paper roll 13 is started, the marker 43 is detected by the marker detection sensor 44, and the detection signal is input to the one-rotation time calculation unit 53 in the overall control unit 46. When the marker 43 is read by the marker detection sensor 44, the one-rotation time calculation unit 53 reads the timer value t1 of the time counter 55 at that time. Then, when the marker 43 is read again by the marker detection sensor 44, the one-rotation time calculation unit 53 similarly reads the timer value t2 of the time counter 55. Next, the one rotation time calculation unit 53 calculates one rotation time T (= t2−t1) of the recording paper roll 13. The calculation result of the one rotation time T is input to the recording paper leading edge determination unit 54.

  When vibration is detected by the vibration detection sensor 40 and a leading edge detection signal is output from the vibration detection sensor 40, the recording paper leading edge determination unit 54 reads the timer value of the time counter 55 at that time and temporarily stores it in the memory 57. Memorize. At this time, if no vibration is detected after a predetermined time has elapsed, the recording paper leading edge determination unit 54 outputs an error signal to the motor control unit 52. When the error signal is input, the rotation of the recording paper roll 13 is stopped, and then an error display is displayed on the display monitor 49.

  Based on the timer value of the time counter 55, when T + α has elapsed since the previous vibration was detected, the vibration is detected again by the vibration detection sensor 40, and when the leading edge detection signal is output again from the vibration detection sensor 40, the recording paper The leading edge determination unit 54 determines that the detected position is the leading edge 11 a of the recording paper 11. If the leading edge detection signal is not output again from the vibration detection sensor 40, the recording sheet leading edge determination unit 54 determines that the leading edge detection signal is a false detection in which vibration other than the passage of the leading edge 11a is detected. Then, the above-described detection / determination work of the leading edge 11a of the recording paper 11 is repeated.

  If it is determined that the vibration detected by the vibration detection sensor 40 is due to the passage of the leading end 11a of the recording paper 11, the motor control unit 52 stops the rotating recording paper roll 13 and then rotates it forward. As a result, the leading end 11 a of the recording paper 11 is separated from the recording paper roll 13 by the separation plate 37. The leading end 11 a of the separated recording paper 11 is guided to the printing unit 15 along a conveyance path formed between the separation plate 37 and the guide plate 38.

  If the passage detection sensor 50 does not detect the passage of the recording paper 11 based on the timer value of the time counter 55 and the passage detection sensor 50 does not detect the passage of the recording paper 11 based on the timer value of the time counter 55, the recording paper 11 is detected. It is determined that the separation of the 11 tips 11a has failed.

  In this case, the motor control unit 52 stops the normal rotation of the recording paper roll 13 and then reverses it again. And the above-mentioned tip separation work is retried. The number of retries for the tip separation work is counted by a retry number counter 59. If this count exceeds a certain value, the rotation of the recording paper roll 13 is stopped, and then an error display is displayed on the display monitor 49.

  Further, the motor control unit 52 reliably feeds the recording paper 11 to the printing unit 15 when the passage detection sensor 50 detects the passage of the recording paper 11 within a predetermined time after the recording paper roll 13 is rotated forward. Therefore, the normal rotation of the recording paper roll 13 is continued. As a result, the leading edge separation operation of the leading edge 11 a of the recording paper 11 is completed, and the recording paper 11 is fed to the printing unit 15.

  As described above, in the present embodiment, the vibration is detected by the vibration detection sensor 40 and the leading edge detection signal is output from the vibration detection sensor 40. Then, after the recording paper roll 13 is rotated once, the leading edge detection signal is regenerated. Since the detection position is determined to be the leading end 11a of the recording paper 11 only when it is output, it is possible to prevent erroneous detection of the leading end 11a of the recording paper 11 by the vibration detection sensor 40. As a result, the recording paper roll 13 can be rotated forward after the leading end 11a of the recording paper 11 has passed through the separation plate 37, so that the leading end 11a is separated from the recording paper roll 13 by the separation plate 37 before the recording paper 11 is wound. Can be made. In addition, the leading end 11a of the recording paper 11 is prevented from being separated at a place other than being in contact with the separation plate 37. Thereby, the recording paper 11 can be reliably fed to the printing unit 15.

When the recording paper 11 fed from the paper supply unit 14 is sandwiched between the conveying roller pair 17 of the printing unit 15, the recording paper 11 is drawn from the recording paper roll 13 by the conveying roller pair 17 and conveyed in the A direction. (See FIG. 1). When the rear end of the recording area (not shown) of the recording paper 11 passes through the thermal head 18, the thermal head 18 in the retracted position is moved to the press contact position, and the heating element array 18 a is moved to the margin portion of the recording paper 11. (Not shown).

  Next, the transport motor 43 is rotated in the reverse direction to transport the recording paper 11 in the B direction. When the recording area of the recording paper 11 reaches the heat generating element array 18a during the conveyance, the heat generating element array 18a is heated based on the image data to be printed, and the Y thermosensitive coloring layer of the recording paper 11 is colored. In this way, a yellow (Y) image is printed line by line in the recording area of the recording paper 11.

  When the printing of the Y image is completed, the thermal head 18 at the press contact position is moved to the retracted position. Next, the recording paper 11 is conveyed in the A direction by the conveying roller pair 17 and at the same time, the Y fixing lamp 26 of the optical fixing device 20 is turned on. The Y fixing lamp 26 is turned off when a recording area (not shown) of the recording paper 11 passes through the optical fixing device 20. As a result, the Y image is fixed.

  When the fixing of the Y image is completed, the recording paper 11 is conveyed in the B direction by the conveying roller pair 17. During this conveyance, a magenta (M) image is printed as in the case of Y image printing. Then, the recording paper 11 is again conveyed in the A direction by the conveying roller pair 17, and the M image is fixed by the M fixing lamp 27. When the fixing of the M image is completed, the recording paper 11 is transported in the B direction by the transport roller pair 17, and a cyan (C) image is printed during the transport in the same manner as when printing the Y and M images.

  When the printing of the C image is completed, the recording paper 11 is transported in the A direction by the transport roller pair 17. Then, it is cut off at a predetermined position by the cutter 21, and a color print (not shown) is discharged from the paper discharge outlet 29. Thereafter, the leading edge of the recording paper 11 is transported to the position of the transport roller pair 17 and enters a standby state for the next printing process. If the next print is not instructed even after a predetermined time has elapsed, the printer 10 is turned off after the recording paper 11 is rewound onto the recording paper roll 12.

  In the above-described embodiment, the vibration detection sensor 40 provided on the separation plate 37 is used as the leading end detection sensor for detecting the leading end 11a of the recording paper 11 on the outer periphery of the recording paper roll 13 being rotated in reverse. Is not limited to this. For example, instead of the vibration detection sensor 40, a laser displacement meter that can detect a step (see FIG. 3) due to the leading end 11a of the recording paper 11, a non-contact eddy current type displacement sensor that detects a change in magnetic resistance caused by the step, etc. Various sensors may be used.

  Moreover, in the said embodiment, although the passage detection sensor 50 is provided in the guide plate 38, this invention is not limited to this, You may be provided in the separation plate 38.

  In this embodiment, the marker 43 is written on the core 12 of the recording paper roll 13 in order to calculate one rotation time T. However, a recording member that records the type information of the recording paper 11 as the marker 43, for example, A paper tube information code (not shown) written on the side surface of the core (paper tube) 12 or a barcode provided on the side surface may be used. Further, instead of marking the marker 43 on the side surface of the core 12, it may be marked on a flange (not shown) attached to the recording paper roll 13.

  In the above-described embodiment, the marker 43 is detected every time. However, one rotation time T in the paper feeding process (tip separation work) performed immediately after the power is turned on is stored, and one rotation time T is stored in the next paper feeding process. The rotation time T obtained last time may be used without obtaining again.

  Further, the present invention is not limited to the paper feeding device of the color thermal printer 10, but is applied to a paper feeding device (paper feeding unit) of various color / monochrome printers such as a photographic printer and an ink jet printer using a recording paper roll. can do.

It is the schematic of the color thermal printer which implemented this invention. It is the schematic of the paper feed part of a color thermal printer. FIG. 3 is an enlarged view of a peripheral surface of a recording paper roll set in a paper feeding unit. It is the graph which showed an example of the detection signal waveform of the vibration detection sensor when a plurality of tip candidates are detected. 6 is a flowchart illustrating print processing of a printer. 6 is a flowchart showing a procedure for separating the leading edge of a recording sheet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Color thermal printer 11 Color thermal recording paper 11a Tip 13 Recording paper roll 14 Paper feed part 15 Printing part 16 Motor 33 Separation unit 37 Separation board 38 Guide board 40 Vibration detection sensor 43 Marker 44 Marker detection sensor 46 General control part 50 Passing detection Sensor 52 Motor control unit 53 One rotation time calculation unit 54 Recording paper leading edge determination unit

Claims (9)

In a paper feeder for a recording paper roll, which stores a recording paper roll wound around a long recording paper in a roll shape so as to be rotatable, pulls out the recording paper from the recording paper roll and feeds it to a printing unit,
Roll rotating means for rotating the recording paper roll forward to feed the recording paper in the paper feeding direction and reversing it to wind up the recording paper;
Roll rotation control means for controlling the roll rotation means so that the recording paper roll is reversely rotated before the recording paper roll is rotated forward.
A leading edge detecting means for detecting a leading edge of the recording paper on the outer periphery of the recording paper roll during the reverse rotation and outputting a leading edge detection signal;
Determination means for determining the detection position as the leading edge of the recording paper when the leading edge detection signal is output again after one rotation of the recording paper roll after the leading edge detection signal is output from the leading edge detection means. And a recording paper roll feeding device.   The determination means determines that the previous tip detection signal output from the tip detection means is a false detection when the tip detection signal is not output again from the tip detection means. 2. A paper feeding device for a recording paper roll according to claim 1.   3. A paper feeding device for a recording paper roll according to claim 1, further comprising a one-rotation time detecting means for detecting one rotation time of the recording paper roll during the reverse rotation. The one rotation time detecting means includes
A marker provided on a side surface of the core;
Marker detecting means provided at a position facing the side surface of the core and detecting the marker;
Based on the detection result of the marker detection means, the one rotation time is calculated from the difference between the time when the marker is first detected and the time when the marker is detected next while the recording paper roll is in reverse rotation. 4. The recording paper roll feeding device according to claim 3, further comprising: a rotation time calculating unit. A separation plate that is brought into contact with the outer peripheral surface of the recording paper roll and is brought into contact with the front end of the recording paper and separated from the recording paper roll when the recording paper roll is rotated forward;
5. The vibration detection sensor according to claim 1, wherein the leading edge detection unit is a vibration detection sensor that is provided on the separation plate and detects vibration caused by contact between the separation plate and the leading edge of the recording paper. The recording paper roll feeding device described.   When the detection unit determines that the detection position is the leading edge of the recording paper, the roll rotation control unit controls the roll rotation unit to stop the recording paper roll being reversely rotated and to rotate forward. 6. A paper feeding device for a recording paper roll according to claim 5, wherein:   7. A paper feeding device for a recording paper roll according to claim 5, wherein the leading edge of the recording paper separated by the separation plate is conveyed toward the print unit along the separation plate. Comprising passage detection means for detecting passage of the recording paper conveyed along the separation plate,
If the passage detection means does not detect the passage of the recording paper even after a lapse of a certain time after the recording paper roll is normally rotated, the roll rotation control means controls the roll rotation means to perform normal rotation. The recording paper roll is reversely rotated after being stopped, and during the rotation, detection of the leading edge of the recording paper by the leading edge detection unit and determination of the leading edge detection signal by the determination unit are performed again. Item 8. A paper feeding device for a recording paper roll according to Item 7. Before rotating the recording paper roll wound up in a roll shape around a long recording paper and feeding the recording paper in the paper feeding direction, reverse the recording paper roll,
Detecting one rotation time of the recording paper roll during the reverse rotation, detecting the leading edge of the recording paper on the outer periphery of the recording paper roll, and outputting a leading edge detection signal;
Only when the leading edge detection signal is output again after the recording paper roll is rotated once after the leading edge detection signal is output, the detected position is determined as the leading edge of the recording paper,
A recording paper roll feeding method, wherein at the time of this determination, the reverse rotation of the recording paper roll is stopped and then rotated forward.

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