Abstract:
A paper magazine to be loaded in an image recording device contains a roll of recording paper, and is provided with a transport mechanism to feed the recording paper out of the paper magazine with holding a leading end of the recording paper. The transport mechanism includes a drive roller and a belt mechanism. The belt mechanism is composed of a pair of pulleys, separated by a particular interval, and a flat belt to encircle the pulleys. The drive roller contacts with the flat belt in the center, pressing it to bend. Making surface contact with the recording paper between the flat belt, the drive roller transports the recording paper without slipping.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a paper magazine for image recording devices such as printers. 
     2. Background Arts 
     A printer for printing an image of a negative film on a photosensitive material such as photographic papers generally pre-loads a paper magazine, which contains a roll of photosensitive material wound around a paper tube. The photosensitive material is drawn from the paper magazine, cut into an intended size, and transported to a printing section. The photosensitive material with an image printed is sent to a subsequent developing apparatus. 
     This kind of paper magazine is disclosed in the Japanese patent laid-open publication No. 07-114108, in which the paper magazine has a drive roller rotated by a drive source in the printer main body and a nip roller facing the drive roller to nip the photosensitive material therebetween so as to transport the photosensitive material. 
     In order to improve a transport stability, the nip roller may nip the photographic paper with high pressure. However, the high nip pressure possibly causes pressure-induced fog or bears nip impressions on the photosensitive material. This problem may be solved by a paper magazine with several pairs of nip rollers, which can reduce the pressure from individual nip rollers while providing sufficient degree of nip pressure in its entirety. Meanwhile, the paper magazine of the Japanese patent laid-open publication No. 07-114108 has a pair of nip rollers to steadily transport the photosensitive material. 
     To change the size of the photosensitive materials, the above described printers require a replacement of the paper magazine itself with another containing the photosensitive material of the intended size. If a leading end of the photosensitive material remains out of the paper magazine during the replacement, the leading end will be exposed. This is the reason the drive roller is rotated backwards as the print operation completes, rewinding the photosensitive material back in the paper magazine to protect the photosensitive material from exposure during the replacement. 
     Since the drive roller and the nip roller always stay in line contact with the photosensitive material in the width direction thereof, leaving the paper magazine unused for a long time will result in bearing a linear impression on the leading end of the photosensitive material. In addition, one or both of these rollers may be deformed because these rollers have soft, rubber-made surfaces. Long-term use of the paper magazine, at the same time, will have an affect on the drive roller and the nip roller to decrease frictional resistance in some part of their surfaces due either to adhesion of paper dust from the photosensitive material, deformation of the roller surface as described above, and degradation of the surface materials. This condition fluctuates feeding force of the drive roller and leads to an error in feed length of the photosensitive material, causing some disadvantages such as unsuccessful setting of the photosensitive material in a cutting position. Further, the drive roller and the nip roller are disposed to nip the side edges of the photographic paper, and such a configuration produces a significant amount of paper dust from the side edges and therefore aggravates the above described disadvantages. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, a primary object of the present invention is to provide a paper magazine which ensures accurate, long-term feed length control to a recording paper while preventing a drive roller from deforming in the surface. Another object of the present invention is to provide the paper magazine which keeps frictional resistance on the surface of the drive roller by preventing generation of paper dust. 
     To achieve the above objects and other objects of the present invention, the paper magazine includes a plurality of pulleys which is separated by particular intervals, a belt which is wound around the plurality of pulleys, and a drive roller which is rotated by driving force from either the inside or the outside of the paper magazine. A surface of the drive roller and an outer surface of the belt between the pulleys come into pressure contact with the recording paper. The belt is driven by the rotation of the drive roller. Any type of belt such as a rubber belt or a leather belt can be employable as long as it is made from an elastic material. Preferable is a flat belt if the pulleys have a roller shape, however, a synchronous belt or a V belt can also be used. In this case, the pulleys will be synchronous or provided with V shape grooves. 
     It is possible to employ a number of belts and drive rollers aligned in the width direction of the recording paper. The belts and the drive rollers should , in this case, lie within the width of the recording paper and not to reach the width directional side edges of the recording paper in order to prevent generation of paper dust. 
     Tension on the belt is determined by the interval between the pulleys, a diameter of the pulleys, and a perimeter of the belt. The tension, in fact, may gradually decreases as the belt is deteriorating and stretching in a long-term use. It is therefore preferable to provide a tension applying mechanism, which imparts the tension of the belt to at least one of the pulleys. 
     According to the present invention, the drive roller makes pressure contact with the periphery of the belt between the plurality of pulleys. The belt partly sticks fast a periphery of the drive roller in an arc, and the drive roller makes surface contact with the recording paper. This posture stables the pressing force of the drive roller, ensuring even pressure contact and consequently improving the paper feed accuracy. At the same time, the surface contact can minimize the chance of bearing the nip impressions on a leading end of the recording paper even if the paper magazine is left unused for a long time. The present invention employs an endless circulating belt, which requires no guide plates for the belt. An embodiment where the belt and the drive roller are arranged not to reach the both ends (or side edges) of the recording paper will effectively reduce the generation of paper dust, and the feeding force (i.e. the frictional resistance) is thereby maintained at proper level. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other features and advantages of the present invention will become apparent from the following detailed descriptions of the preferred embodiments in conjunction with the accompanying drawings, which are given by way of illustration only and thus do not limit the present invention. In the drawings, the same reference numerals designate like or corresponding parts throughout the several views, and wherein: 
         FIG. 1  is a perspective view of a paper magazine with a lid being lifted; 
         FIG. 2  is a side view of the paper magazine with the lid being lifted; 
         FIG. 3  is an explanatory view of the paper magazine mounted in an image recording apparatus; 
         FIG. 4  is a perspective view schematically illustrating key components of a drive roller unit and a driven belt unit; and 
         FIG. 5  is a perspective view illustrating the drive roller in pressure contact with a flat belt. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to  FIG. 1  and  FIG. 2 , a paper magazine  10  is composed of a magazine main body  13 , which can load a winding core  11  supporting a photosensitive material roll (not shown) from an open section  12 , and a lid  15  attached to one end of the magazine main body  13  through a hinge  14 . The lid  15  rotates on the hinge  14  to close the open section  12 . 
     In the magazine main body  13  and the lid  15 , bearings  16  are provided to hold both ends of the winding core  11 . The bearings  16  have an octagonal shape to fit onto holders  17  on the both ends of the winding core  11 , and thereby the holders  17  are unrotatably caught in the bearings  16  when the winding core  11  is set in the paper magazine  10 . 
     The winding core  11  is includes a roll core  20  and a pair of flanges  21 ,  22 . The flanges  21 ,  22  hold the photosensitive material roll while positioning the center of the photosensitive material in the width direction to the center of a transport passage in the paper magazine  10 . The holders  17  are rotatably attached to the both ends of the roll core  20 . Provided between the holder  17  and the roll core  20  is a friction member  23  such as felt, which produces some friction when the roll core  20  rotates in the holders  17 . Therefore the winding core  11  is not able to rotate in the paper magazine  10  unless a certain degree of torque is applied thereto, and unexpected rotation of the winding core  11  will be prevented. Note that the photosensitive material is wound on the periphery of the roll core  20  between the flanges  21 ,  22 . 
     The magazine main body  13  is provided with a drive roller unit  25 , a detection lever  26 , a pair of guide members  27 ,  28 , and a roller assembly  29 . Displaceable in the width direction of the photosensitive material, the pair of guide members  27 ,  28  can be rearranged according to the size of the photosensitive material so that the interval between them can fit to the width of a photosensitive material to be used. In the lid  15 , a driven belt unit  30  is provided. 
     In  FIG. 3 , the paper magazine  10  is mounted in a loading chamber  33  of an image recording device  32  with the magazine main body  13  facing up and the lid  15  down. Guided by the roller assembly  29  between the flanges  21 ,  22  while regulated by the guide members  27 ,  28  in the width direction, a photosensitive material  31  passes between the drive roller unit  25  and the driven belt unit  30 . The photosensitive material  31  is fed to the image recording device  32  through an opening  34  formed across joint portions of the unit body  13  and the lid  15 . 
     The magazine main body  13  is provided with a shutter mechanism (not shown), which blocks light coming inside the paper magazine  10  through the opening  34 . The shutter mechanism is composed of a mount detective pin and a shutter member which opens the transport passage for the photosensitive material  31  inside the opening  34  in response to a displacement of the mount detective pin. The shutter member is usually set in a closed position by the bias of a spring, blocking the incoming light from the opening  34  to the inside of the paper magazine  10 . When the paper magazine  10  is mounted in the loading chamber  33  such that the opening  34  faces the transport passage for the photosensitive material  31  in the image forming apparatus, the mount detective pin is pushed and displaced to move the shutter member to an open position. The photosensitive material  31  will consequently be transferred from and into the opening  34 . Formed to project within a concave portion, the mount detective pin will hardly be pushed and displaced outside the image recording apparatus. The shutter member, in addition, will block the incoming light to the inside of the paper magazine  10  even on the move to the open position when the paper magazine  10  is completely mounted in the loading chamber  33 . The shutter mechanism may have a solenoid or a motor, instead of the displaceable mount detective pin, to open and close the shutter member. 
     As shown in  FIG. 4 , the drive roller unit  25  is constituted of a pair of drive rollers  35 ,  36  and a joint section  37  (see  FIG. 1 ) at one end of a shaft  40  of these rollers. Disposed outside the paper magazine  10 , the joint section  37  couples with a driver mechanism  38  in the image recording device  32  when the paper magazine  10  is mounted in the loading chamber  33 . The driver mechanism  38 , as shown in  FIG. 3 , is provided with a pulse motor  39 , a driver  42 , and a controller  43  for the drive rollers  35 ,  36 . The controller  43  controls the forward/backward rotations and the stop of the drive rollers  35 ,  36 . 
     As shown in  FIG. 4 , the drive roller unit  25  includes of a pair of drive rollers  35 ,  36  and a joint section  37  (see  FIG. 1 ) at one end of a shaft  40  of these rollers. Disposed outside the paper magazine  10 , the joint section  37  couples with a driver mechanism  38  in the image recording device  32  when the paper magazine  10  is mounted in the loading chamber  33 . The driver mechanism  38 , as shown in  FIG. 3 , is provided with a pulse motor  39 , a driver  42 , and a controller  43  for the drive rollers  35 ,  36 . The controller  43  controls the forward/backward rotations and the stop of the drive rollers  35 ,  36 . 
     The detection lever  26  can rotate between a projecting position into the transport passage of the photosensitive material  31  and a retreating position away from the transport passage. The detection lever  26  stays in the retreating position when the photosensitive material  31  lies in the transport passage, but moves in the projecting position as soon as the photosensitive material  31  runs out. Running out of the photosensitive material  31  is therefore easily determined by detecting the position of the detection lever  26 . The position detection is made by a sensor in the image recording device  32 . The sensor outputs signals to the controller  43  in the driver mechanism  38 , and thereby the rotation of the pulse motor  39 , eventually of the drive rollers  35 ,  36 , is thereby controlled. The sensor outputs signals to the controller  43  in the driver mechanism  38 , and thereby the rotation of the pulse motor  39 , eventually of the drive rollers  35 ,  36 , is thereby controlled. 
     As shown in  FIG. 4 , the drive roller unit  25  has a number of rubber rollers, which are fixed to the shaft  40  with a certain interval between them. These rubber rollers are symmetrically arranged about a center of the transport passage in the width direction. The innermost pair is the drive rollers  35 ,  36  while the rests are sub drive rollers  41 . On one end of the shaft  40 , the joint section  37  is fixed. The detection lever  26  is placed between the drive rollers  35 ,  36 . The guide members  27 ,  28  are disposed upstream of the drive rollers  35 ,  36  in a transport direction of the photosensitive material  31 , and the roller assembly  29  is disposed upstream of the guide members  27 ,  28 . 
     The driven belt unit  30  includes a first pulley unit  44 , a second pulley unit  46 , a pair of flat belts  47  , 48 , and a pair of coil springs  60 ,  61  as the tension applying mechanism of the present invention. The first pulley unit  44  has a pair of first pulleys  49 ,  50  and a number of driven rollers  51  on a shaft  52 . The first pulleys  49 ,  50  are crown shaped rollers, with their centers swelling like a barrel, to prevent the flat belts from leaning on one side. The first pulleys  49 ,  50  are also symmetrically arranged about the center of the transport passage in the width direction so as to correspond in position to the drive rollers  35 ,  36 . The first pulleys  49 ,  50  are provided with roller bearings toward the shaft  52 , and rotatable on the shaft  52  consequently. The driven rollers  51  are equal in number to the sub drive rollers  41 , and are separately arranged to face their corresponding sub drive rollers  41 . Being rotatable on the shaft  52 , the driven rollers  51  act as guide rollers, which prevent the side edges of the photosensitive material from clogging in the paper magazine even when a wide photosensitive material is used. The shaft  52  is rotatably supported on the lid  15 . 
     The second pulley unit  46  is disposed upstream of the first pulleys  49 ,  50  in the transport direction, and is composed of a pair of second pulleys  53 ,  54  and a shaft  55  for supporting these second pulleys. The second pulleys  53 ,  54  are also crown shaped rollers, with their centers swelling like a barrel, to prevent the flat belts from leaning on one side. The second pulleys  53 ,  54  are symmetrically arranged about the center of the transport passage in the width direction. Further, the second pulleys  53 ,  54  are provided with roller bearings toward the shaft  55 , and rotatable on the shaft  55  consequently. The shaft  55  is rotatably supported on the lid  15 . 
     The flat belt  47  encircles the first and second pulleys  49 ,  53  while the flat belt  48  encircles the first and second pulleys  50 ,  54 . As shown in  FIG. 5 , the drive rollers  35 ,  36  contact with the peripheries of flat belts  47 ,  48  respectively, in avoiding the contact area of the flat belts to the first and second pulleys, between the first pulley unit  44  and the second pulley unit  46 . The shaft  55  for supporting the second pulleys  53 ,  54  is biased by springs  60 ,  61  to move in a direction away from the first pulleys  49 ,  50 , that is, the opposite direction to the transport direction (or a rewind direction of the photosensitive material). 
     The force of the springs puts a certain amount of tension on the pair of flat belts  47 ,  48 , and the pressure contact of the drive rollers  35 ,  36  will thus cause the flat belts  47 ,  48  to bend as the lid  15  is pressed down to the magazine main body  13 . Since the springs  60 ,  61  expand and contract to keep the tension on the flat belts  47 ,  48  within a proper range, the pressure of the drive rollers  35 ,  36  on the flat belts  47 ,  48  is always fairly constant even if the pressure of the lid  15  is changed on the unit body  13 . 
     There are several width to the photosensitive material  31 . The position of the drive rollers  35 ,  36  and the flat belts  47 ,  48  is therefore determined with reference to the narrowest type photosensitive material. The drive rollers  35 ,  36  and the flat belts  47 ,  48  are arranged within the width of the photosensitive material and not to reach the side edges of the photosensitive material in the width direction. Such an arrangement can reduce the chance of generation of paper dust from the photosensitive material  31 . 
     Described next is the operation of the above configuration, which starts with loading the photosensitive material  31  in the paper magazine  10 . With the unit body  13  down, the lid  15  is lifted to unload the winding core  11 . The flanges  21 ,  22  are temporarily detached from the winding core  11 , and after the photosensitive material  31  is set to the roll core  20 , they are attached to the winding core  11  again. The winding core  11  with the photosensitive material  31  is then placed in the magazine main body  13  and, a leading end of the photosensitive material  31  is pulled out through the roller assembly  29  to beyond the drive rollers  35 ,  36 . As the lid  15  is being closed, the leading end of the photosensitive material  31  is held between the drive rollers  35 ,  36  and the flat belts  47 ,  48 . 
     The prepared paper magazine  10  is mounted in the loading chamber  33  of the image recording device  32 . Achieved on this loading operation are electrical and mechanical connections of the paper magazine  10  to the image recording device  32 , drive control of the joint section  37  by the driver mechanism  38  in the image recording device  32 , and positional detection of the detection lever  26  by the sensor of the image recording device  32 . 
     As soon as the paper magazine  10  is mounted in the loading chamber  33 , the image recording device  32  automatically performs a pre-cut operation to the leading end of the photosensitive material  31  as follows. The driver mechanism  38  of the image recording device  32  rotates the drive rollers  35 ,  36  in the transport direction, carrying the leading end of the photosensitive material  31  to the opening  34 . Since the drive rollers  35 ,  36  press the flat belts  47 ,  48  to bend, the flat belts  47 ,  48  partly encircle the peripheries of the drive rollers  35 ,  36  like an arc, and the photosensitive material  31  makes surface contact with the drive rollers  35 ,  36 . The surface contact pressure is fairly constant even with some factors on the peripheries of the drive rollers  35 ,  36  to reduce the frictional resistance, the photosensitive material  31  is therefore transported accurately. In addition, the expansion and contraction of the springs  60 ,  61  move the shaft  55  of the second pulleys  53 ,  54  to change the distance from the first pulleys  49 ,  50 , and thereby the tension on the flat belts  47 ,  48  is maintained within a proper range. 
     As shown in  FIG. 3 , the image recording device  32  includes a cutter mechanism  70  on the transport passage of the photosensitive material  31 . In the pre-cut operation, the driver mechanism  38  operates the drive rollers  35 ,  36  to rotate forward until the leading end of the photosensitive material  31  passes over the cutter mechanism  70 , and the cutter mechanism  70  cuts out an excess portion of the leading end of the photosensitive material  31 . Then, the driver mechanism  38  operates the drive rollers  35 ,  36  to rotate backward until the leading end of the photosensitive material  31  arrives at a return position anywhere between the cutting position of the cutter mechanism  70  and the pressure contact area of the drive rollers  35 ,  36  to the flat belts  47 ,  48 . 
     The leading end of the photosensitive material  31  passes over the detection lever  26  on the way to the return position, allowing the detection lever  26  to project into the transport passage. Through this movement, the driver mechanism  38  recognizes the arrival of the leading end of the photosensitive material  31  at the return position, and stops the backward rotation of the drive rollers  35 ,  36  to complete the pre-cut operation of the image recording device  32 . Meanwhile, the winding core  11  does not rotate backward (i.e. in the rewind direction) in the paper rewind operation because the rewinding distance, from the cutter mechanism  70  to the return position, is considerably short. The photosensitive material  31  does not twine around the core but hangs inside the paper magazine  10 . 
     When the print command is given to the image recording device  32 , the driver mechanism  38  rotates the drive rollers  35 ,  36  to transport the photosensitive material  31 , as described above. After transporting an intended amount of the photosensitive material  31  to the cutter mechanism  70 , the driver mechanism  38  temporarily stops operating and the cutter mechanism  70  cuts the photosensitive material  31  into a sheet. At this instant, the leading end of the photosensitive material  31  is held with a transport roller pair  71  provided in the image recording device  32 . The cutout sheet, a photosensitive material sheet  31   a , is transported by the transport roller pair  71  to the subsequent recording section for image recording, and then, to the developing section for developing. This series of operations is repeated until the intended number of photosensitive material sheets  31   a  are transported with the transport roller pair  71  to the recording section. 
     When the photosensitive material  31  runs out, the detection lever  26  projects into the transport passage as shown by a dotted line in  FIG. 3 , and the driver mechanism  38  stops driving and indicates the running out of photosensitive material  31  externally. This indication can signal users to re-load the photosensitive material  31  in the paper magazine  10 . 
     When the intended number of sheets are transported, the driver mechanism  38  rotates the drive rollers  35 ,  36  backward to rewind the photosensitive material  31  in the paper magazine  10 . The leading end of the photosensitive material  31  thus moves from the cutting position of the cutter mechanism  70  back to the return position until the detection lever  26  projects into the transport passage. Then, the driver mechanism  38  stops the backward rotation. The leading end of the photosensitive material  31  will thus be held with the drive rollers  35 ,  36  and the flat belts  47 ,  48 , which make pressure contact with each other. 
     Completely covered in the paper magazine  10  in this state, the leading end of the photosensitive material  31  is safe from exposure. In addition, in making the surface contact, not line contact, with the drive rollers  35 ,  36  and the flat belts  47 ,  48 , the leading end of the photosensitive material  31  will be free from the linear nip impressions on the surfaces. 
     Although two pairs of the drive roller and the flat belt are aligned along the width of the photosensitive material  31  in the above embodiment, one pair or more than two pairs can be provided. 
     The orientation of the paper magazine  10  in the loading chamber  33  is not limited to the above embodiment where the flat belts  47 ,  48  lie below the drive rollers  35 ,  36 . The paper magazine  10  may be mounted in the loading chamber  33  with the opening  34  facing up. 
     In the above embodiment, the photosensitive material  31  is not rolled up inside the paper magazine  10 , but it is possible to rotate the winding core  11  backward only in the paper rewind operation to roll up the photosensitive material  31  around the roll core  20 . 
     The pulleys  49 ,  50 ,  53 ,  54  are attached to the shafts  52 ,  55  through the roller bearings in the above embodiment. The pressing force also affects on the flat belts  47 ,  48 , and thereby the shafts  52 ,  55  and the inner races of the roller bearings receive a radial load. The radial load can cause the roller bearings to slide, and possibly abrade the shafts  52 ,  55 . It is therefore preferable to provide resin-made supports between the shafts  52 ,  55  and the inner races of the roller bearings so as to prevent the roller bearings from coming into direct contact with the shafts  52 ,  55 . 
     Although the flat belts  47 ,  48  are respectively wound across the couples of pulleys  49 ,  53  and  50 ,  54  in the above embodiment, the pulleys for a single flat belt can be three or more in number. 
     In the above embodiment, the joint section  37  is provided on one end of the shaft  40  of the drive roller unit  25 , and the driving force is applied from the outside of the paper magazine  10  through the joint section  37 . However, the paper magazine  10  may incorporate a motor to rotate the drive rollers  35 ,  36 . 
     As described so far, the present invention is not to be limited to the above embodiments, and all matter contained herein is illustrative and does not limit the scope of the present invention. Thus, obvious modifications may be made within the spirit and scope of the appended claims.