Patent Publication Number: US-2006001729-A1

Title: Paper feeder for roll-shaped recording paper

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a paper feeder for a roll-shaped recording paper, which comprises a paper-feed roller and an edge separator.  
      2. Description of the Related Art  
      In a conventionally-known paper feeder, a recording-paper roll is rotated in a feeding direction to advance a paper edge to a paper feeding port. This paper feeder is disposed in a magazine to which the recording-paper roll is set. Alternatively, the paper feeder is disposed in a loading chamber to be loaded with the recording-paper roll. After the recording-paper roll has been set, an edge separating claw and a paper-feed roller come into contact with a circumferential surface of the recording-paper roll at positions having an interval in a circumferential direction. The paper-feed roller rotates the recording-paper roll in the feeding direction. The edge separating claw disposed at a downstream side of the paper-feed roller in the feeding direction peels the paper edge from the circumferential surface of the recording-paper roll to conduct the paper edge to the paper feeding port. Therefore, when the recording-paper roll has just been set, it is required to position the paper edge at a rotational position between the edge separating claw and the paper-feed roller.  
      In consideration of this, the printer described in Japanese Patent Laid-Open Publication No. 2000-169013 comprises an edge detecting mechanism for automatically detecting the edge of the recording-paper roll. This edge detecting mechanism rotates the recording-paper roll in a take-up direction to detect the edge during the rotation thereof. The edge detecting mechanism comprises a base roller for abutting on the circumferential surface of the recording-paper roll, an actuator lever for rotating around the base roller, a driven roller attached to a halfway portion of the actuator lever, a first spring for urging the actuator lever so as to make the driven roller abut on the circumferential surface of the recording-paper roll, and a switch for outputting a detection signal. The switch outputs the detection signal in association with a movement of the actuator lever when the driven roller has passed the edge during a reverse rotation of the recording-paper roll.  
      As described above, the edge detecting mechanism includes the driven roller for abutting on the circumferential surface of the recording-paper roll. In this mechanism, the movement of the driven roller having passed the edge is detected by a detector. This kind of the mechanism is also employed for a printer described in Japanese Patent Laid-Open Publication No. 2002-179308.  
      The above edge detecting mechanism rotates the recording-paper roll in the take-up direction to automatically detect the rotational position of the edge in the circumferential direction of the recording-paper roll. Thus, an operation is simple at the time of setting of the recording-paper roll. However, since the edge detecting mechanism needs many parts of the rollers, the detector and so forth besides the paper-feed roller and the edge separating claw, a structure thereof becomes complicated and a lot of trouble is taken in an assembly operation. Moreover, the cost of the entire apparatus increases because of the large number of the parts. Meanwhile, the edge detecting mechanism has a small size for the purpose of detecting the edge of the recording-paper roll. Thus, when setting the recording-paper roll, the edge detecting mechanism is likely to be broken or damaged if the recording-paper roll hits this mechanism due to a setting attitude thereof. Further, the edge detecting mechanism is likely to malfunction due to an effect of paper dust collected during long-term use, and due to deterioration of the spring.  
     SUMMARY OF THE INVENTION  
      In view of the foregoing, it is a primary object of the present invention to provide a low-cost paper feeder in which it is possible to surely detect a rotational position of a paper edge of a recording-paper roll.  
      In order to achieve the above and other objects, the paper feeder according to the present invention comprises a pair of roll holders, an edge-indexing member, a detector and a controller. The roll holders are respectively attached to both ends of a core of a recording-paper roll so as to catch the recording-paper roll. The roll holders rotate together with the core. The edge-indexing member is rotatably attached to an outer surface of one of the roll holders. An indicia for pointing a position of the paper edge is indicated on the edge-indexing member. After setting the roll holder to the recording-paper roll, the edge-indexing member is attached to the roll holder so as to point the paper edge with the indicia. While the recording-paper roll is rotated in a take-up direction, the detector detects a rotational position of the edge-indexing member to send a detection signal in accordance with the rotational position. On the basis of the detection signal, the controller sets the recording-paper roll to an initial rotational position.  
      Incidentally, the edge-indexing member may be provided with the indicia and an object to be detected by the detector. The object to be detected is fixed to a position related to the indicia. It is needless to say that the indicia itself may be detected by the detector.  
      In the paper feeder according to the present invention, the edge-indexing member attached to one of the roll holders is set such that the indicia points the paper edge. The rotational position of the edge-indexing member is detected by the detector. Thus, it is possible to easily find the edge position of the recoding-paper roll. Moreover, it is possible to manufacture the paper feeder at low cost, since a number of parts is reduced in comparison with a conventional paper-edge detecting mechanism. Further, since the detector detects the rotational position of the edge-indexing member from the side of the roll holder, damage and so forth are hardly caused and the detection of the rotational position is surely performed for a longer time in comparison with a conventional mechanism in which a detector is disposed on a circumferential surface of the recording-paper roll. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The above objects and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments of the invention when read in conjunction with the accompanying drawings, in which:  
       FIG. 1  is a perspective view partially showing a printer using a paper feeder according to the present invention;  
       FIG. 2  is an exploded perspective showing a recording-paper roll unit;  
       FIG. 3  is a partial perspective view of the printer showing a loading chamber of the printer;  
       FIG. 4  is an explanatory illustration showing the loading chamber loaded with the recording-paper roll unit;  
       FIG. 5  is a schematic section view showing a sensor disposed in the loading chamber;  
       FIG. 6  is an explanatory illustration schematically showing an electrical structure of the printer; and  
       FIG. 7  is an explanatory illustration showing the loading chamber in which the recording-paper roll is set to an initial rotational position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)  
      As shown in  FIG. 1 , a printer  10  using a paper feeder according to the present invention has a loading lid  11  provided at a lateral side thereof. The loading lid  11  is slidable in a drawing direction. When the loading lid  11  is drawn, a loading chamber  12  is exposed from the inside. A recording-paper roll unit  13  is removably loaded in the loading chamber  12 .  
      As shown in  FIG. 2 , the recording-paper roll unit  13  comprises a recording-paper roll  14  and a pair of roll holders  15  and  16 . The recording-paper roll  14  is formed such that a strip of a recording paper  18  is wound around a core  17  of a hollow cylindrical shape. Incidentally, an edge  18   a  of the new recording-paper roll  14  is secured with a tape  9 .  
      A code  19  representing management information of the recording paper  18  is recorded on one end of the core  17 . The code  19  represents the information concerning a sort of the recording paper, a manufacturer, manufacture information and an identification number. Further, the code  19  also represents the information concerning thermal sensitivity when the recording paper is a thermosensitive recording paper. For example, the code  19  is formed in a bar-code style wherein a low-reflection region and a high-reflection region are combined. The low-reflection region includes a quiet zone and a black bar. The high-reflection region is a white bar. By the way, the code is not limited to the bar-code style, and may have a circular-shape style. In this case, the code is formed such that the inside of the circular area corresponds to the white bar of the high-reflection region and the outside of the circular area corresponds to the black bar of the low-reflection region.  
      The roll holders  15  and  16  comprise flanges  20  and  21 , shafts  22  and  23 , and core shafts  24  and  25 . The flanges  20  and  21  catch both ends of the recording-paper roll  14  to position the recording paper  18  in a width direction thereof. The core shafts  24 ,  25  and the shafts  22 ,  23  are respectively formed so as to straightly protrude in opposite directions at both sides of the flanges  24  and  25 . The core shafts  24  and  25  are fitted into the core  17  of the recording-paper roll  14 . The shafts  22  and  23  are rotatably attached to bearings disposed at the loading chamber  12 . The core shafts  24  and  25  are inserted into the core  17  to catch both ends of the recording-paper roll  14  with the flanges  20  and  21 . Thus, the roll holders  15  and  16  rotate together with recording-paper roll  14 .  
      The roll holder  15  is provided with an edge index  26  for indicating a position of the edge  18   a  residing at the circumferential surface of the recording-paper roll  14 . The edge index  26  is rotatable around the shaft  22  and is attached to the opposite side to the inner side of the flange  20  coming into contact with the end side of the recording-paper roll  18 . The edge index  26  has a dial-shaped circumference on which knurls are formed for putting a finger. Further, a front side of the index  26  is provided with an arrow-shaped indicia  28  and a high-reflection member  29 . The edge index  26  is set to a rotational position where an arrow direction of the indicia  28  is adjusted to the edge  18   a  residing at the circumferential surface of the recording-paper roll  14 . The high-reflection member  29  is disposed at a position shifted by a predetermined angle, for example by 180 degrees, from the indicia  28  relative to the shaft  22  (rotational center). The high-reflection member  29  is formed from material having higher reflectance in comparison with the other portion (low-reflection portion). This material is a mirror seal, for instance. The high-reflection member  29  is detected by a photoelectronic sensor disposed at the loading chamber  12 . Incidentally, it is desirable to provide a ratchet stop and a click mechanism between the edge index  26  and the roll holder  15  so that click feeling is obtained every predetermined angle when the rotational position of the edge index  26  is adjusted. Further, by the ratchet stop and the click mechanism, the set position is prevented from being mistakenly shifted.  
      As shown in  FIG. 3 , a pair of side plates  30  and  31  is disposed in the loading chamber  12  so as to face each other in a direction perpendicular to a drawing direction of the loading lid  11 . The side plates  30  and  31  are respectively provided with guide grooves  32  and  33  into which the shafts  22  and  23  of the roll holders  15  and  16  are inserted. Bearings  34  and  35  are formed downstream in a guiding direction of the guide grooves  32  and  33  to guide the shafts  22  and  23 . The pair of the bearings  34  and  35  rotatably supports the pair of the shafts  22  and  23  at a constant position.  
      As shown in  FIG. 4 , the loading chamber  12  is provided with a paper-feed roller  37 , an edge separating claw  38  and a sensor unit  39 . The paper-feed roller  37  comes into contact with a circumferential surface of the recording-paper roll  14  to rotate this roll  14  in a paper-feed direction and a take-up direction. The edge separating claw  38  is disposed at a downstream side of the paper-feed roller  37  in the paper-feed direction of the recording-paper roll  14  to peel and separate the edge  18   a  from the recording-paper roll  14  rotating in the paper-feed direction. Drive of the paper-feed roller  37  is inputted from the printer. Incidentally, the paper-feed roller  37  and the edge separating claw  38  are adapted to approach the recording-paper roll  14  in accordance with a change of a winding diameter thereof so as to abut on the circumferential surface of the recording-paper roll  14 .  
      The sensor unit  39  is attached to the side plate  30 . The sensor unit  39  is a unit component in which photoelectronic sensors  40  and  41  are unitized. The photoelectronic sensor  40  for detecting the edge  18   a  senses the high-reflection member  29  and is disposed at an orbit position of the high-reflection member  29  rotating around the shaft  22  set to the bearing  34 . The photoelectronic sensor  41  for reading the code  19  is disposed at a rotational orbit position of the end of the core  17  on which the code  19  is recorded. The photoelectronic sensor  40  for detecting the edge  18   a  is adapted to detect the high-reflection member  29  when the indicia  28  points an area extending between the paper-feed roller  37  and the edge separating claw  38 . Incidentally, the couple of the photoelectronic sensors  41  and  40  are arranged along a line passing the center of the shaft  22  set to the bearing  34  for the purpose of unitization.  
      Each of the photoelectronic sensors  40  and  41  is a reflective sensor having a light emitter and a light receiver. The photoelectronic sensor  41  reads the code  19  while the recording-paper roll  14  is rotated in the take-up direction. The photoelectronic sensor  40  detects the high-reflection member  29  while the recording-paper roll  14  is rotated in the take-up direction.  
      As shown in  FIG. 5 , the couple of the photoelectronic sensors  40  and  41  are fixed to a block  43 , which is attached to the side plate  30 . The photoelectronic sensor  40  for detecting the edge  18   a  is disposed so as to confront a surface  26   a  having the high-reflection member  29 . Meanwhile, the photoelectronic sensor  41  is disposed so as to confront the end  17   a  of the core  17  on which the code  19  is recorded. Between the photoelectronic sensor  41  and the end  17   a , the roll holder  15  is located. In this embodiment, the roll holder  15  is made of transparent material so that the code  19  is read out through the roll holder  15 . If only the roll holder  15  to which the edge index  26  is fixed is made of the transparent material, it is possible to prevent the roll holders  15  and  16  from being mistakenly attached to both ends of the recording-paper roll  14 . However, both of the roll holders  15  and  16  may be made of the transparent material. By the way, the edge index  26  has a doughnut shape so as not to disturb the detection of the photoelectronic sensor  41  by its opening. Thus, it is unnecessary to form the edge index  26  from the transparent material.  
      As shown in  FIG. 6 , a signal obtained from each of the photoelectronic sensors  40  and  41  is sent to a printer controller  50 , which controls a paper-feed motor  52  via a driver  51 . Drive of the paper-feed motor  52  is transmitted to the paper-feed roller  37  disposed in the loading chamber  12 . Further, the printer controller  50  controls a printing unit  54  on the basis of the read code  19  to record an optimum image. Incidentally, the printer controller  50  integrally controls the respective sections along a program read from a ROM  55 .  
      Next, an operation of the above structure is described below. When assembling the recording-paper roll unit  13 , the core shafts  24  and  25  of the roll holders  15  and  16  are respectively inserted into openings of both ends of the core  17 . After insertion, the edge index  26  attached to the roll holder  15  is set to the rotational position where the indicia  28  points the edge  18   a  of the recoding-paper roll  14 . And then, the tape  9  securing the edge  18   a  of the recording-paper roll  14  is peeled. Upon this, the recording-paper roll unit  13  becomes available.  
      Successively, the loading lid  11  of the printer  10  is drawn to expose the loading chamber  12 . The recording-paper roll unit  13  is set, bringing the flanges  20  and  21  to the exposed loading chamber  12 . At this time, the shaft  22  of the roll holder  15  having the edge index  26  is set to the bearing  34  of the pair of the bearings  34  and  35  residing in the loading chamber  12 . By doing so, the recording-paper roll unit  13  is set in a state that the edge  18   a  is fed by rotating the paper-feed roller  37  in the paper-feed direction.  
      Upon closing the loading lid  11 , the paper-feed roller  37  and the edge separating claw  38  come into contact with the circumferential surface of the recording-paper roll  14 . After that, it is detected whether there is or not the recording-paper roll unit  13 . When there is the roll unit  13 , the printer controller  50  performs a print preparing operation in which the operation for reading the code  19  is performed first, and then, the operation for detecting the rotational position of the edge index  26  is performed. After performing these operations, the printer  10  is kept in a readiness state.  
      In the operation for reading the code  19 , the paper-feed motor  52  is driven to rotate the paper-feed roller  37  in the take-up direction. At this time, the recording-paper roll  14  makes at least one rotation. During this rotation, the photoelectronic sensor  41  is monitored to read the code  19  on the basis of a high-level signal and a low-level signal obtained from the photoelectronic sensor  41 .  
      After reading the code  19 , the printer controller  50  continues rotating the paper-feed roller  37  in the take-up direction to monitor the edge-detecting photoelectronic sensor  40  during this time. The photoelectronic sensor  40  detects the high-reflection member  29 . The printer processor  50  halts the drive of the paper-feed motor  52  upon reception of a leading-edge signal, which is obtained when the signal from the photoelectronic sensor  40  rises from the low level to the high level. Alternatively, the printer controller  50  halts the drive of the paper-feed motor  52  after a predetermined period has passed from the reception of the leading-edge signal. In virtue of this, as shown in  FIG. 7 , the rotation of the recording-paper roll  14  is stopped at a position where the high-reflection member  29  substantially overlaps with the photoelectronic sensor  40  in a side viewing direction. At this time, the edge  18   a  residing on the circumferential surface of the recording-paper roll  14  is kept in an initial rotational position located between the paper-feed roller  37  and the edge separating claw  38 . Hereby, the printer  10  is set in a print readiness state. In this way, reading the code  19  and detecting the rotational position of the edge index  26  are successively performed while the paper-feed roller  37  is rotated in the take-up direction. Thus, the print preparing operation is speedily performed.  
      The recording paper  18  of this embodiment is a well-known color thermosensitive recoding paper in which cyan, magenta and yellow thermosensitive coloring layers are formed on a support in order.  
      The printing unit  54  includes a carrying roller pair, a thermal head and an optical fixing unit and so forth. The carrying roller pair nips the edge  18   a  of the recording paper  18  and carries it in the printing unit  54 . The thermal head performs thermal recording for the respective thermosensitive coloring layers of the recording paper  18 . The optical fixing unit optically fixes the respective thermosensitive coloring layers, for which thermal recording has been performed, by applying ultraviolet rays.  
      Upon a print instruction, the printer controller  50  drives the paper-feed motor  52  and reverses the paper-feed roller  37  to rotate the recording-paper roll  14  in the paper-feed direction. Hereby, the edge  18   a  is separated from the roll  14  by means of the edge separating claw  38 , and the edge  18   a  is carried toward a paper slot  60 . Then, the recording paper  18  is fed to the printing unit  54 . The fed recording paper  18  is carried by the carrying roller pair in the printing unit  54  to pass the thermal head and the optical fixing unit in order. During this time, print processing is performed in a three-color frame sequential manner to record a full-color image. The processed recording paper  18 , for which the print processing has been performed, is cut by a cutter into a predetermined size. The cut recording paper  18  is discharged to the outside of the printer  10 . Meanwhile, the recording paper  18  from which the image-recoded paper is separated is rewound into the loading chamber  12  by reversing the paper-feed roller  37 .  
      The printing unit  54  is provided with an edge detecting sensor for detecting the edge  18   a  of the recording paper  18 . At the time of rewind of the recording paper  18 , control is performed such that the paper-feed motor  52  is driven for a predetermined period after detecting the edge  18   a  with the edge detecting sensor. If the paper-feed motor  52  is a pulse motor, control is performed such that the paper-feed motor  52  is driven by a number of predetermined pulses after detecting the edge  18   a . In virtue of this control, the recording-paper roll  14  is set again to the initial rotational position where the edge  18   a  is located between the paper-feed roller  37  and the edge separating claw  38 .  
      In the printer  10 , it is possible to designate a print number at the time of print instruction. When the designated print number is two or more, print processing is successively performed by times of the designated number. After completing the successive processing, the recording paper  18  is rewound.  
      With respect to the recording paper  18 , there are some kinds having different widths. When the recording paper  18  is exchanged to another one having a different width, the loading lid  12  is drawn to remove the recording-paper roll unit  13 . Further, the couple of the roll holders  15  and  16  are detached from the recording-paper roll unit  13 . And then, the detached roll holders  15  and  16  are attached to the new recoding-paper roll  14 , and the rotational position of the edge index  26  is set. In this way, the rotational position of the edge index  26  is set whenever the recording-paper roll unit  13  is placed. Owing to this, it is possible to surely and easily detect the edge  18   a  of the recording paper roll  14 .  
      In the above embodiment, the recording-paper roll  14  having the paper information is used. The present information, however, is not limited to this. It is possible to use the recording-paper roll having no paper information. In this case, the photoelectronic sensor  41  may be omitted. Moreover, in this case, it is unnecessary to form the roll holder  15  from the transparent material.  
      In the above embodiment, the edge index  26  is provided with the indicia  28  and the high-reflection member  29 . The present invention, however, is not limited to this. The indicia  28  may be detected as the high-reflection member by the photoelectronic sensor  40 . Moreover, the high-reflection member  29  disposed on the surface  26   a  of the edge index  26  is detected by the photoelectronic sensor  40  of which the light emitter faces the surface  26   a . However, the high-reflection member may be disposed on a circumferential surface of the edge index  26 , and the light emitter of the photoelectronic sensor may point in a diameter direction to detect the high-reflection member. Further, the photoelectronic sensor is not exclusive as the detecting member. A proximity switch may be used. In this case, a metal member is disposed on the edge index  26  instead of the high-reflection member. In the above embodiments, detection is performed in the non-contact manner. However, contact-type detecting members comprising a projection and a microswitch may be used.  
      The above embodiment relates to the stationary type in which a rotational axis of the recording-paper roll  14  is rotatably kept in the constant position. However, this is not exclusive. It is possible to adopt a moving type in which the shafts  22  and  23  of the recording-paper roll unit  13  move toward the paper-feed roller  37  in accordance with the change of the winding diameter of the recoding-paper roll  14 . In this case, the photoelectronic sensors  40  and  41  are moved in association with the movement of the shafts  22  and  23  of the recording-paper roll unit  13  in the same direction and at the same speed.  
      In the above embodiment, the recording-paper roll  14  is rotated in the paper-feed direction and the take-up direction by rotating the paper-feed roller  37  forward and backward. However, only when the recording paper is taken up, drive may be inputted into the roll holder from the printer to rotate the recording-paper roll  14  in the take-up direction.  
      Although the present invention has been fully described by way of the preferred embodiments thereof with reference to the accompanying drawings, various changes and modifications will be apparent to those having skill in this field. Therefore, unless otherwise these changes and modifications depart from the scope of the present invention, they should be construed as included therein.