Patent Publication Number: US-2023143445-A1

Title: Printer

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2021-182092, filed on Nov. 8, 2021, the entire contents of which are incorporated herein by reference. 
     FIELD 
     Embodiments described herein relate generally to a printer. 
     BACKGROUND 
     In a related art, a printer that prints while conveying a strip-shaped sheet was used. As such a printer, for example, there is a receipt printer. In addition, some such printers enable both a full cut that completely cuts the ejected sheet in the width direction and a partial cut that leaves a partial area of the width direction (for example, the central portion). Further, some such printers convey and eject the sheet upwards. 
     Some printers that eject sheet upward as described above have been devised as disclosed in JP-A-2007-076134. That is, to prevent the inconvenience that the fully cut sheet falls below the cut position, the ribs provided at the sheet ejection port hold the sheet by alternately pressing the sheet from the front and back. 
     Here, the structure for holding the full-cut sheet as described above does not correspond to the ejection of the partially cut sheet. In the case of full cut, the cut sheet held by the ribs overlaps with the sheet to be conveyed next, and thus, a frictional force acts between the sheets. As a result, the cut sheet also moves between the ribs together with the next sheet. However, since the partially cut sheet does not overlap with the next sheet in the thickness direction, the sheet is not conveyed by the frictional force between the sheets as described above. In the case of partial cut, the conveying force is transmitted from the rear sheet to the front sheet only at the connected part. Thus, if the sheet holding force of the ribs is too strong, the sheet is broken at the connected part of the front and rear sheet and a sheet jam occurs. Further, if the ribs are simply lowered or the number of ribs is reduced to weaken the sheet holding force of the ribs, the originally required function of holding the fully cut sheet becomes uncertain depending on the degree of the ribs. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view illustrating the appearance of a printer according to an embodiment; 
         FIG.  2    is a schematic cross-sectional view showing an example of the internal structure of the printer; 
         FIG.  3    is a plan view showing an example of the appearance of a sheet ejection port; 
         FIG.  4    is a plan view of the sheet ejection port showing an example of the degree of curvature of an ejected sheet; 
         FIG.  5    is a perspective view showing an example of the shape of a first protrusion; 
         FIG.  6 - 1    is a diagram showing a partial cross-sectional view of a sheet passage path at the sheet ejection port; 
         FIG.  6 - 2    is a diagram showing a partial cross-sectional view of the sheet passage path at the sheet ejection port; 
         FIG.  7    is a diagram showing a partial cross-sectional view of a state of the ejection and stacking of fully cut sheets; 
         FIG.  8 - 1    is a diagram showing a partial cross-sectional view of a state of sheet ejection in the partial cut; 
         FIG.  8 - 2    is a diagram showing a partial cross-sectional view of a state of sheet ejection in the partial cut; 
         FIG.  8 - 3    is a diagram showing a partial cross-sectional view of a state of sheet ejection in the partial cut; and 
         FIG.  9    is a realistic view of a partially cut sheet and a connected portion. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure provide a printer having a structure capable of holding a full-cut sheet ejected upward and having a structure in which jam of a partial-cut sheet is unlikely to occur. 
     In general, according to one embodiment, a printer includes a printing unit configured to print on a strip-shaped sheet, a housing configured to house the sheet and the printing unit and provided with a sheet ejection port for ejecting the sheet that passed through the printing unit upward, a cutting unit arranged between the printing unit and the sheet ejection port and configured to cut the sheet by either a first method of cutting the sheet in the entire width direction or a second method of leaving the central portion of the sheet in the width direction, first protrusions protruding from the inner periphery of the sheet ejection port, and provided at a plurality of locations along the width direction of the sheet to face a first surface, which is the surface of the sheet on the side to be printed, and second protrusions protruding from the inner periphery of the sheet ejection port, provided at a plurality of locations along the width direction of the sheet at positions deviated from the first protrusions in the sheet width direction to face a second surface, which is the back surface of the first surface of the sheet, and configured to bend the sheet in an undulating shape in the width direction between the first protrusion and the second protrusion, in which a protrusion height of at least one of the first protrusions and the second protrusions in a predetermined region of the central portion of the sheet in the width direction is lower than protrusion heights of the first protrusions and the second protrusions in other regions. 
     The embodiment will be described with reference to the drawings.  FIG.  1    is a perspective view illustrating the appearance of a printer  1  according to an embodiment.  FIG.  2    is a schematic cross-sectional view showing an example of the internal structure of the printer  1 . 
     The printer  1  is, for example, a thermal printer that prints information such as characters and figures on a sheet. The printer  1  is connected to, for example, a POS (Point of Sales) terminal (not shown), receives commodity information and sales information related to commodities sold to customers at a store from the POS terminal, prints the information on the sheet, and dispenses the sheet as a receipt (discharge of the sheet, sheet ejection). 
     The printer  1  includes a housing  2 , a storage unit  3 , a sheet ejection port  4 , a printing unit  5 , and a cutting unit  6 . 
     The housing  2  includes a main body portion  21  and a lid portion  22 . The main body portion  21  is a container having an opening on one side and includes the storage unit  3  for storing a roll sheet  9  inside. One side of the lid portion  22  is rotatably supported near the edge of the opening of the main body portion  21 . With the rotation of the lid portion  22 , the opening of the main body portion  21  is opened and closed, whereby the storage unit  3  is opened and closed. The roll sheet  9  is taken in and out of the main body portion  21  with the lid portion  22  open. 
     The roll sheet  9  is a roll of a strip-shaped sheet (for example, heat sensitive paper)  91 , and the sheet  91  is pulled out from the outer peripheral portion at the end of the roll. The outer diameter of the roll sheet  9  gradually decreases as the sheet  91  is pulled out. 
     The printer  1  prints information on the sheet  91  pulled out from the roll sheet  9  stored in the storage unit  3  and ejects the sheet  91  that passed through the printing unit  5  from the sheet ejection port  4 . 
     The sheet ejection port  4  is formed between the end of the lid portion  22  on the opposite side of the rotating end and the main body portion  21 . The sheet ejection port  4  is a gap (slit) between a surface  41  facing the printing surface of the sheet  91  and a surface  42  facing the back surface of the printing surface of the sheet  91 . The surface  41  is a part of the main body portion  21  and the surface  42  is a part of the lid portion  22 . The sheet ejection port  4  is open upward and the printer  1  ejects the sheet  91  that passed through the printing unit  5  upward. 
     The printing unit  5  includes a printing head  51  and a platen  52 . 
     The print head  51  is provided at a substantially intermediate position between the storage unit  3  and the sheet ejection port  4  in the main body portion  21  and is provided in the middle of the conveyance path of the sheet  91  pulled out from the roll sheet  9 . The print head  51  is a line thermal head in which a large number of heat-generating elements are arranged on the line. The print head  51  drives the heat generating elements corresponding to the print pattern among the heat generating elements aligned on one line to generate heat, thereby, heating the sheet  91  to print information. The printed sheet  91  is discharged from the sheet ejection port  4  to the outside of the housing  2 . 
     The platen  52  is a cylindrical roller whose surface is formed of an elastic material at least and is rotatably attached to the lid portion  22 . If the lid portion  22  closes the opening of the main body portion  21 , the platen  52  is located at a position facing the print head  51  and presses the print head  51 . In this state, the sheet  91  pulled out from the roll sheet  9  is sandwiched between the print head  51  and the platen  52 . The platen  52  rotates by the driving force of a motor (not shown) being transmitted, pulls out the sheet  91  from the roll sheet  9 , and conveys the sheet toward the sheet ejection port  4 . 
     The cutting unit  6  is arranged between the printing unit  5  and the sheet ejection port  4  and cuts the sheet  91  along the width direction of the sheet  91 . The sheet width direction, the sheet thickness direction, and the sheet conveyance direction are orthogonal to each other. 
     The cutting unit  6  is driven by selectively adopting one of the following two methods as the cutting method. A first method is a method also called full cut, which cuts the sheet  91  in the entire width direction. A second method is a method also called partial cut, which leaves the central portion of the sheet  91  in the width direction. 
     The cutting unit  6  includes, for example, a fixed blade  61  having a straight cutting edge and a movable blade  62  having a cutting edge having a V-shaped recess in the center. The movable blade  62  is driven by a drive unit such as a motor (not shown), so as to move in a direction in which the cutting edge of the movable blade  62  is close to and separated from the cutting edge of the fixed blade  61 . The moving direction of the movable blade  62  substantially coincides with, for example, the sheet thickness direction. In such a structure, full cut and partial cut can be used properly depending on the moving distance of the movable blade  62  with respect to the fixed blade  61 . That is, by stopping the movement of the movable blade  62  to the extent that the V-shaped valley of the movable blade  62  does not reach the cutting edge of the fixed blade  61  and is maintained in a slightly separated state, the central portion of the sheet  91  in the width direction can be left uncut, which makes a partial cut. 
       FIG.  3    is a plan view showing an example of the appearance of the sheet ejection port  4 . The printer  1  further includes first protrusions  7  ( 71  to  76 ) and second protrusions  8  ( 81  to  83 ) inside the sheet ejection port  4 . 
     The first protrusions  7  ( 71  to  76 ) protrude from the surface  41  constituting the inner periphery of the sheet ejection port  4 , are provided at a plurality of locations along the width direction of the sheet  91 , and face the surface of the sheet  91  (printing surface, first surface) on the side to be printed. Similarly, the second protrusions  8  ( 81  to  83 ) protrude from the surface  42  constituting the inner periphery of the sheet ejection port  4 , are provided at a plurality of locations along the width direction of the sheet  91 , and face the back surface (second surface) of the printing surface of the sheet  91 . 
     Each of the protrusions  71  to  76  and  81  to  83  has a plate shape and is provided side by side in the width direction of the sheet  91  with the plate thickness direction facing the width direction of the sheet  91 . 
     Further, the protruding direction of each of the protrusions  7  and  8  is, for example, along the thickness direction of the sheet  91  conveyed at each position. As a result, each of the protrusions  7  and  8  changes the moving direction of the sheet  91  during conveyance in the thickness direction thereof. 
     The first protrusions  7  are composed of the protrusions  71  and  72  located at the central portion in the width direction of the sheet  91 , the protrusions  73  and  74  provided at positions sandwiching the protrusions  71  and  72  in the sheet width direction, and the protrusions  75  and  76  further sandwiching the protrusions  71  to  74  in the sheet width direction. Further, the second protrusions  8  are composed of the protrusion  81  located at the central portion in the width direction of the sheet  91 , and the protrusions  82  and  83  provided at positions sandwiching the protrusion  81  in the sheet width direction. 
     The second protrusions  8  are provided at positions deviated from the first protrusions  7  in the width direction of the sheet  91 . As a result, each of the protrusions  7  and  8  is alternately located in the order of the first protrusion  75 , the second protrusion  83 , the first protrusions  73  and  71 , the second protrusion  81 , the first protrusions  72  and  74 , the second protrusion  82 , and the first protrusion  76  in the sheet width direction. Further, as a result, the sheet  91  is curved in an undulating shape (wavy shape) in the width direction between the first protrusion  7  and the second protrusion  8 .  FIG.  4    is a plan view of the sheet ejection port showing an example of the degree of curvature of the ejected sheet  91 . The sheet  91  is in close contact with the protrusions  7  and  8  due to its curved waist (elasticity that tries to return to a straight line from the curved state) and is held by the frictional force acting between the sheet  91  and the protrusions  7  and  8 . 
     In the present embodiment, the protrusions  71  and  72  at the central portion in the sheet width direction are set to have a lower (smaller and shorter) protrusion height than the other protrusions  73  to  76 . Further, in the present embodiment, the protrusions  73  to  76  are formed to have a constant protrusion height. Further, the protrusions  81  to  83  are formed to have a constant protrusion height in the present embodiment. As a result, in the predetermined region of the central portion of the sheet  91  in the width direction, the distance between the top of the first protrusion  7  and the top of the second protrusion  8  is wider (larger) than that in the other regions. 
     In the present embodiment, the heights of the protrusions  71  to  76  and  81  to  83  are set as described above, but in the implementation, the protrusion height of at least one of the first protrusions  7  and the second protrusions  8  in a predetermined region in the central portion in the width direction of the sheet  91  may be set lower than the protrusion heights of the first protrusions  7  and the second protrusions  8  in the other regions. 
       FIG.  5    is a perspective view showing an example of the shape of the first protrusions  71  to  73 . The first protrusions  74  to  76 , which are not shown in  FIG.  5   , have the same shape as the first protrusion  73 . As shown in this drawing, the first protrusion  73  and others have a mountain shape, and the first protrusions  71  and  72  have a trapezoidal shape. More details will be described with reference to  FIGS.  6 - 1  and  6 - 2   . 
       FIGS.  6 - 1  and  6 - 2    are drawings showing a partial cross-sectional view of the passage path of the sheet  91  in the sheet ejection port  4 .  FIG.  6 - 1    is a cross section taken along the line A-A in  FIG.  3    and  FIG.  6 - 2    is a cross section taken along the line B-B in  FIG.  3   .  FIGS.  6 - 1  and  6 - 2    are drawings as viewed from the width direction of the sheet  91 . 
     As shown in  FIG.  6 - 1   , the mountain-shaped first protrusion  75  includes a top  751 , a hypotenuse  752  rising diagonally from the inner peripheral surface  41  of the sheet ejection port  4  from the upstream side to the downstream side in the sheet conveyance direction to reach the top  751 , and a side  753  descending from the top  751  to the inner peripheral surface  41 . 
     The side  753  is an edge portion of the first protrusion  75  on the downstream side in the sheet conveyance direction. The side  753  extends in a direction intersecting the sheet conveyance direction and the sheet width direction. Since such a side  753  is not parallel to the lower side of the fully cut sheet  91 , the fully cut sheet  91  can be supported. 
     Further, the second protrusion  83  (the same applies to the second protrusions  81  and  82 ) has a mountain shape similar to that of the first protrusions  73  to  76 . That is, the second protrusion  83  includes a top  831 , a hypotenuse  832  rising diagonally from the inner peripheral surface  42  of the sheet ejection port  4  from the upstream side to the downstream side in the sheet conveyance direction to reach the top  831 , and a side  833  descending from the top  831  to the inner peripheral surface  42 . 
     Next, as shown in  FIG.  6 - 2   , the first protrusion  71  (the same applies to the first protrusion  72 ) having a lower protrusion height than the other first protrusions  73  to  76  in the central portion in the width direction of the sheet has a trapezoidal shape. More specifically, the first protrusions  71  and  72  have a shape in which a predetermined height including the top  751  is removed from the same mountain shape as the first protrusion  75  to be substantially parallel to the surface  41 . Therefore, the first protrusions  71  and  72  have a short hypotenuse  752  and a side  753 . 
     Further, in the present embodiment, the first protrusions  7  and the second protrusions  8  are provided to be positioned to deviate from each other in the sheet conveyance direction. As a result, the shape of the sheet conveyance path seen from the sheet width direction includes S-shaped undulation instead of a straight line, as shown in  FIGS.  6 - 1  and  6 - 2   . 
     More specifically, the first protrusions  7  are arranged to be located above the second protrusions  8  (that is, on the downstream side in the sheet conveyance direction). Further, in the present embodiment, the first protrusions  7  ( 71  to  76 ) are provided more than the second protrusions  8  ( 81  to  83 ), and therefore, the distance between the first protrusions  7  ( 71  to  76 ) is narrow. As a result, the first protrusion  7  is suitable as a place where the fully cut sheet  91  is placed and stacked (accumulated). 
     Further, in the present embodiment, the first protrusions  7  and the second protrusions  8  are provided so that the hypotenuse  752  and the side  833  face each other through the gap when viewed from the sheet width direction. As a result, the first protrusions  7  and the second protrusions  8  do not overlap (are not superimposed) when viewed from the sheet width direction. This structure and the shape of the sheet conveyance path including the S-shaped undulation described above make it possible to realize a moderate holding of the sheet  91  in the sheet ejection port  4  of the present embodiment. Moderate holding here means that the fully cut sheet  91  can be held between the first protrusion  7  and the second protrusion  8  to the extent that jam does not occur between the first protrusion  7  and the second protrusion  8  while the cutting unit  6  is in a partial cut operation. 
       FIG.  7    is a diagram showing a partial cross-sectional view of the state of ejection and stacking of a fully cut sheet  92 . If the cutting unit  6  cuts the sheet  91  printed by the printing unit  5 , in the case of full cut, the cut sheet  92  is held by the addition of the undulating force in the sheet width direction between the first protrusion  7  and the second protrusion  8 . This prevents the occurrence of the inconvenience that the sheet  92  falls between the fixed blade  61  and the movable blade  62  and is cut twice. 
     If the next sheet  91  is conveyed in the above-mentioned state, the sheet  91  partially overlaps with the cut sheet  92  in the thickness direction between the first protrusion  7  and the second protrusion  8 . If the sheet  91  is further conveyed, a frictional force acts on the contact surface between the sheet  91  and the sheet  92 , and the sheet  92  is conveyed together with the sheet  91 . The sheet  92  that passed through the top  751  is stacked on the side  753  of the first protrusion  7 . 
       FIGS.  8 - 1  to  8 - 3    are diagrams showing a partial cross-sectional view of the state of the ejection of the sheet  91  in the partial cut. The sheet  91  shown in  FIG.  8 - 1    is in a state before being cut by the cutting unit  6 . If the sheet  91  is partially cut by the cutting unit  6 , the state shown in  FIG.  8 - 2    is obtained. In  FIG.  8 - 2   , reference numeral  93  indicates a location (connected portion)  93  in which both ends are cut off and the central portion is connected. Further, reference numeral  94  indicates a portion (partially cut sheet)  94  on the downstream side of the connected portion  93 . 
     Here,  FIG.  9    is a diagram realistically showing the partially cut sheet  94  and the connected portion  93 . As shown in this drawing, the connected portion  93  between the partially cut sheet  94  and the sheet  94  is actually a portion having no length that can be illustrated when viewed from the sheet width direction, but for convenience of description, the connected portion is represented by dotted lines in  FIGS.  8 - 2  and  8 - 3   . 
     As shown in  FIG.  8 - 2   , the lower ends of both ends in the width direction of the portion  94  on the downstream side of the connected portion  93  are curled toward the movable blade  62  according to the winding direction of the roll sheet  9 . In this state, the portion  94  on the downstream side of the connected portion  93  (that is, the partially cut sheet) is held between the first protrusions  7  and the second protrusions  8  in the same manner as the fully cut sheet  92 . 
     In the case of partial cut, the conveyed sheet  91  and the portion  94  do not overlap in the thickness direction, and thus, the sheet  91  pushes up the portion  94  only by the connected portion  93 . Therefore, if the portion  94  is held too strongly by the protrusions  7  and  8 , a jam will occur. As a countermeasure, in the printer  1  of the present embodiment, first, the distance between the first protrusion  7  and the second protrusion  8  in the central portion in the sheet width direction is wider than in other regions (both ends in the sheet width direction). As a result, the load applied to the connected portion  93  and its peripheral portion is smaller than that in the other regions. 
     Further, in the printer  1  of the present embodiment, the first protrusions  7  and the second protrusions  8  are arranged to face each other through a gap when viewed from the sheet width direction and not to overlap when viewed from the sheet width direction. According to such an embodiment, the inconvenience that the sheet  91  is held too strongly is eliminated. 
     Moreover, in the printer  1  of the present embodiment, the first protrusion  7  and the second protrusion  8  are positioned to deviate from each other in the sheet conveyance direction, whereby the sheet conveyance path seen from the sheet width direction has an undulating shape such as an S-shape. As a result, the fully cut sheet  92  is less likely to fall to the cutting unit  6 , and the inconvenience that the sheet  92  is cut twice by the cutting unit  6  is less likely to occur. 
     If the sheet  91  is conveyed from the state of  FIG.  8 - 2   , the next printing is performed, and the next partial cut is performed, the state shown in  FIG.  8 - 3    is obtained. As shown in  FIGS.  8 - 2  and  8 - 3   , the partially cut portion  94  of the sheet  91  is curled according to the winding direction of the roll sheet  9  and with a curvature according to the remaining diameter of the roll sheet  9 . As a countermeasure against jam caused by this curl, the protrusions  7  and  8  of the present embodiment are arranged to realize a sheet conveyance path (preferably a sheet conveyance path bent in the curl direction of the portion  94 ) that does not go against the curl direction of the portion  94 . According to such an embodiment, even if the curl of the sheet  91  is strong, jam is unlikely to occur. 
     As described above, according to the present embodiment, it is possible to provide the printer  1  having a structure in which the fully cut sheet  92  to be ejected upward can be held and the partially cut portion  94  is less likely to be jammed. 
     In the present embodiment, the protrusions  7  and  8  have a rib-like shape, and the holding force of the sheet  91  at the sheet ejection port  4  is adjusted depending on the number of ribs. At the time of implementation, the protrusions  7  and  8  may be configured, for example, by the coexistence of thick convex portions and thin convex portions in the sheet width direction. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.