Patent Publication Number: US-2020290374-A1

Title: Printer

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is based on and claims priority to Japanese patent application No. 2019-043543, filed on Mar. 11, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     The present disclosure relates to a printer. 
     Conventionally, a printer including a mechanism of aligning a platen roller and a thermal head is known (see, for example, JP2012-218288A). 
     JP2012-218288A discloses a configuration in which the platen roller is supported by a first support member and a second support member to be movable in a pressing direction to the thermal head and a direction vertical to the pressing direction within a predetermined range. The platen roller and the thermal head are thereby aligned. 
     SUMMARY 
     However, as the configuration described in JP2012-218288A includes a configuration that moves the platen roller in the two directions such as a pressing direction to the thermal head and a direction vertical to the pressing direction, the configuration that aligns the platen roller and the thermal head is complex. 
     It is therefore, an object of the present invention is to provide a printer capable of aligning a platen roller and an image forming portion with a simple configuration. 
     To achieve the above object, a printer includes a transport roller that is disposed in a casing, and transports a sheet to be fed from roll paper, an image forming portion that is disposed in a cover of the casing, and forms an image on the sheet, and a platen roller that is disposed in the casing to face the image forming portion, wherein the image forming portion is movable in transport directions of the sheet, and the platen roller is movable in directions substantially vertical to the transport directions. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view illustrating a printer of an embodiment. 
         FIG. 2  is a perspective view illustrating the printer of the embodiment when a cover is open. 
         FIG. 3  is a cross section view illustrating a printer of the embodiment. 
         FIG. 4  is a perspective view describing a moving mechanism of a thermal head of the embodiment. 
         FIG. 5  is a perspective view describing a moving mechanism of a platen roller of the embodiment. 
         FIG. 6  is a cross section view illustrating the thermal head in an initial position and the platen roller in an initial position in the embodiment. 
         FIG. 7  is a cross section view illustrating the thermal head in a standby position and the platen roller in the initial position in the embodiment. 
         FIG. 8  is a cross section view illustrating the thermal head in the standby position and the platen roller in a pressed position in the embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     With respect to the use of plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity. 
     Hereinafter, an embodiment for achieving a printer of the present disclosure will be described with reference to drawings. 
     The printer in the embodiment is applied to a sublimation type thermal transfer printer. 
       FIG. 1  is a perspective view illustrating the printer of the embodiment.  FIG. 2  is a perspective view illustrating the printer of the embodiment when a cover is open.  FIG. 3  is a cross section view illustrating the printer of the embodiment. Hereinafter, the configuration of the printer of the embodiment will be described with reference to  FIGS. 1 to 3 . 
     As illustrated in  FIGS. 1, 2 , the printer  1  includes a box casing  2 , an upper cover  3  as a cover provided in an upper opening portion  2   a  formed in a top surface of the casing  2 , and a front cover  4  provided in a front opening portion  2   b  formed in a front surface of the casing  2 . 
     As illustrated in  FIG. 3 , the casing  2  includes, inside thereof, roll paper R which supplies a sheet S as a recording medium, an ink ribbon T, a thermal head  30  as an image forming portion, a platen roller  40 , a cutter unit  7  as a cutting portion, and a driving roller  21  as a transport roller. 
     The sheet S fed from the roll paper R is wound around the driving roller  21  and a driven roller  23  as a transport roller. The sheet S is transported in a transport path X 1  in a feeding direction D 1  as a transport direction, and is discharged from an exit  8 . 
     For example, photographic paper thicker than plain paper is used for the roll paper R. The roll paper R is rotatably held by a roll paper holder  11  connected to a motor. 
     The driving roller  21  and the driven roller  23  are attached to the casing  2 , and are disposed along the transport path X 1 . The driving roller  21  is connected to a motor to be rotatable in a positive direction (counterclockwise direction) or a negative direction (clockwise direction) opposite to the positive direction. A counter roller  22  as a transport roller is disposed to face the driving roller  21 . 
     The counter roller  22  is attached to the casing  2 , and is disposed along the transport path X 1 . The counter roller  22  is movable to the driving roller  21 . When the sheet S is transported, the counter roller  22  contacts the driving roller  21 , and rotates according to the driving roller  21 . When the driving roller  21  rotates in the positive direction, the driving roller  21  and the counter roller  22  transport the sheet S in the feeding direction D 1  while sandwiching the sheet S therebetween. When the driving roller  21  rotates in the negative direction opposite to the positive direction, the driving roller  21  and the counter roller  22  transport the sheet S in a drawing back direction D 2  as the transport direction while sandwiching the sheet S therebetween. The counter roller  22  separates from the driving roller  21  when the sheet S is not transported. 
     The thermal head  30  is attached to the upper cover  3 , and is disposed along the transport path X 1 . The thermal head  30  is disposed downstream of the driving roller  21  in the feeding direction D 1  of the sheet S. 
     The platen roller  40  is attached to the casing  2 , and is disposed along the transport path X 1  to face the thermal head  30 . 
     The cutter unit  7  is attached to the casing  2 , and is disposed in front of the exit  8  in the feeding direction D 1 . The cutter unit  7  cuts the sheet S which is transported in the transport path X 1 . 
     The ink ribbon T is a band-shaped sheet including respective ink regions for yellow Y, magenta M, and cyan C and a region for overcoat OP, which are repeatedly disposed in a longitudinal direction. The ink ribbon T is held by a ribbon supply reel  12  which feeds the ink ribbon T and a ribbon winding reel  13  which winds the ink ribbon T. 
     The ribbon winding reel  13  is connected to a motor to rotate in a rotation direction E 1 . When the ribbon winding reel  13  rotates in the rotation direction E 1 , the ink ribbon T is fed from the ribbon supply reel  12 . The ink ribbon T fed from the ribbon supply reel  12  is transported in a ribbon transport direction D 3  to pass between the thermal head  30  and the platen roller  40  via driven rollers  25 ,  26 , and is wound around the ribbon winding reel  13 . 
       FIG. 4  is a perspective view describing a moving mechanism of the thermal head of the embodiment. Hereinafter, the moving mechanism of the thermal head  30  of the embodiment will be described with reference to  FIG. 4 . 
     The thermal head  30  includes a head main body  31  and a regulating member  32  attached to the head main body  31 . 
     The thermal head  30  is supported by two supporting members  30  attached to a base member  35  via the regulating member  32 . The base member  35  is attached to the upper cover  3 . 
     The length of the head main body  31  in the longitudinal direction is longer than the width of the sheet S. The regulating member  32  is attached to both end portions of the head main body  31  in the longitudinal direction by a screw, for example. The regulating member  32  is disposed outside the sheet S in the width direction. The regulating member  32  includes a hole into which the screw is inserted. This hole may be a long hole, so that the position of the regulating member  32  to be attached to the thermal head  30  in the transport direction is adjustable. 
     The regulating member  32  is made of a sheet metal, and includes a first regulating portion  32   a,  an insertion hole  32   c,  a small piece portion  32   d,  and a hook portion  32   e.    
     The first regulating portion  32   a  is provided in an outer edge of the regulating member  32 . The first regulating portion  32   a  is disposed upstream of the platen roller  40  in the drawing back direction D 2 . The first regulating portion  32   a  extends in a direction substantially vertical to the transport direction (feeding direction D 1 , drawing back direction D 2 ). The first regulating portion  32   a  contacts a bearing  41  of the platen roller  40  to regulate the thermal head  30  from moving in the drawing back direction D 2 . 
     The insertion hole  32   c  is a long hole having a long side in the transport direction. An after-described projection portion  36   c  is inserted into the insertion hole  32   c.    
     The small piece portion  32   d  extends upward, and includes, in the leading end thereof, the hook portion  32   e.  A tension spring  38  as an after-described first biasing member is attached to the hook portion  32   e.    
     The support member  36  is made of resin, and includes a first wall  36   a  and a second wall  36   b  to have an L shape in section. The first wall  36   a  includes a cylindrical projection portion  36   c  projecting toward the other support member  36 . The second wall  36   b  includes a through-hole  36   d  into which the small piece portion  32   d  is inserted. The length of the through-hole  36   d  in the longitudinal direction is longer than the width of the small piece portion  32   d.    
     A first end of the tension spring  38  as the first biasing member is attached to the base member  35  and a second end of the tension spring  38  is attached to the hook portion  32   e.    
     When the thermal head  30  is attached to the support member  36 , an outer surface of the regulating member  32  contacts an inner surface of the first wall  36   a  of the support member  36 , and the thermal head  30  is regulated from moving in the longitudinal direction of the head main body  31 . 
     The projection portion  36   c  of the support member  36  is inserted into the insertion hole  32   c  of the regulating member  32 , and the thermal head  30  is regulated from moving in the directions vertical to the transport directions (feeding direction D 1 , drawing back direction D 2 ). 
     The small piece portion  32   d  of the regulating member  32  is inserted into the through-hole  36   d  of the support member  36 , and the second end of the tension spring  38  is hooked to the hook portion  32   e.  The hook portion  32   e  is thereby biased in the drawing back direction D 2 . 
     The thermal head  30  is thereby movable in the transport directions (feeding direction D 1 , drawing back direction D 2 ) only. That is, the thermal head  30  is immovable in the directions vertical to the transport directions (feeding direction D 1 , drawing back direction D 2 ) and the longitudinal direction of the head main body  31 . 
     The thermal head  30  is biased in the drawing back direction D 2  by the tension spring  38 . That is, when an image is formed on the sheet S, the thermal head  30  is biased in the drawing back direction D 2  in which the sheet S is transported. The first regulating portion  32   a  is configured to regulate the thermal head  30  from moving in the drawing back direction D 2 . 
       FIG. 5  is a perspective view describing a moving mechanism of the platen roller  40  of the embodiment. Hereinafter, the moving mechanism of the platen roller  40  of the embodiment will be described with reference to  FIG. 5 . 
     The platen roller  40  includes the bearing  41  outside the sheet S to be fed in the width direction. The platen roller  40  is attached to the casing  2  via a lever  42 . The bearing  41  is provided according to the regulating member  32 . That is, the bearing  41  is disposed outside the sheet S in the width direction. 
     The lever  42  is made of metal, for example, and includes a first arm portion  42   a  and a second arm portion  42   b  to have a V shape. A convex portion  42   c  is provided in a leading end of the first arm portion  42   a.  The first arm portion  42   a  is provided with a through-hole  42   d  into which an end portion of the platen roller  40  is inserted to be rotatably supported. 
     The leading end of the second arm portion  42   b  is provided with a hook portion  42   e.  A first end of a tension spring  45  as a second biasing member is hooked to the hook portion  42   e.  A second end of the tension spring  45  is fixed to the casing  2 . 
     The first arm portion  42   a  includes, in a root portion thereof, a rotation shaft  43  about which the lever  42  rotates. The rotation shaft  43  is attached to the casing  2 , for example. 
     The convex portion  42   c  is pushed downwardly by a not shown cam. The lever  42  thereby rotates in a direction H 1 . In this case, the platen roller  40  moves in a direction F 1  separating from the thermal head  30 . The direction F 1  is substantially vertical to the transport directions (feeding direction D 1 , drawing back direction D 2 ). 
     When the amount of pushing the convex portion  42   c  downwardly by the cam is decreased, the lever  42  rotates in a direction H 2 . In this case, the platen roller  40  moves in a direction F 2  coming close to the thermal head  30 . The direction F 2  is substantially vertical to the transport directions (feeding direction D 1 , drawing back direction D 2 ). In this case, the lever  42  is biased in the direction H 2  by the tension spring  45 . That is, the platen roller  40  is biased in the direction F 2  coming close to the thermal head  30  by the tension spring  45 . The platen roller  40  is thereby pushed to the thermal head  30 . 
     The platen roller  40  is thereby movable in the direction vertical to the transport directions (feeding direction D 1 , drawing back direction D 2 ) only. That is, the platen roller  40  is immovable in the transport directions. 
       FIG. 6  is a cross section view illustrating the thermal head  30  in an initial position and the platen roller  40  in an initial position in the embodiment.  FIG. 7  is a cross section view illustrating the thermal head  30  in a standby position and the platen roller  40  in the initial position.  FIG. 8  is a cross section view illustrating the thermal head  30  in the standby position and the platen roller  40  in a pressed position. Hereinafter, the operation of the printer  1  of the embodiment will be described with reference to  FIG. 3  and  FIGS. 6 to 8 . 
     In the printer  1  configured as described above, when the upper cover  3  is open, as illustrated in  FIG. 6 , the thermal head  30  is biased by the tension spring  38  in the drawing back direction D 2 , and the small piece portion  32   d  contacts the side of the through-hole  36   d.  The thermal head  30  is thereby located in an initial position P 1  which is a rear position in the printer  1 . In this case, the platen roller  40  is located in an initial position Q 1  separated from the thermal head  30 . 
     When the upper cover  3  is closed, as illustrated in  FIG. 7 , the first regulating portion  32   a  of the regulating member  32  contacts the bearing  41  of the platen roller  40 , and the thermal head  30  moves to a standby position P 2  moved in the feeding direction D 1  against the biasing force of the tension spring  38 . In this case, the platen roller  40  is located in the initial position Q 1  separated from the thermal head  30 . 
     When image data is input to the printer  1  to start a printing operation, as illustrated in  FIG. 3 , the roll paper holder  11  rotates and the driving roller  21  rotates in the positive direction, so that the sheet S fed from the roll paper R is transported in the transport path X 1  in the feeding direction D 1 . 
     Next, the sheet S is transported in the drawing back direction D 2 , and an image is formed on the sheet S by the thermal head  30 . 
     In this case, as illustrated in  FIG. 8 , the platen roller  40  moves to a pressed position Q 2  which presses the thermal head  30 . When the platen roller  40  is located in the pressed position Q 2 , and the thermal head  30  is pressed by the platen roller  40  via the sheet S and the ink ribbon T, the thermal head  30  generates heat, and transfers sublimating dye ink applied to the ink ribbon T onto the same area of the sheet S to form the image on the sheet S. 
     The sheet S is repeatedly reciprocated in accordance with the formation of the image of each color (yellow Y, magenta M, cyan C, and overcoat OP), and an image in which the respective colors are combined is formed on the same area of the sheet S. 
     Next, the sheet S is transported in the transport path X 1  in the feeding direction D 1 , is cut by the cutter unit  7 , and is discharged from the exit  8 . 
     An operation of the printer of the embodiment will be described. The printer  1  of the embodiment includes the transport roller (driving roller  21 , driven roller  23 , counter roller  22 ) that is disposed in the casing  2  and transports the sheet S fed from the roll paper R, the image forming portion (thermal head  30 ) that is disposed in the cover (upper cover  3 ) of the casing  2  and forms the image on the sheet S, and the platen roller  40  that is disposed in the casing  2  to face the image forming portion (thermal head  30 ). The image forming portion (thermal head  30 ) is movable in the transport directions (feeding direction D 1 , drawing back direction D 2 ) of the sheet S, and the platen roller  40  is movable in the directions (direction F 1 , direction F 2 ) substantially vertical to the transport directions (feeding direction D 1 , drawing back direction D 2 ) ( FIG. 3 ). 
     In the transport directions (feeding direction D 1 , drawing back direction D 2 ), when the platen roller  40  and the image forming portion (thermal head  30 ) are relatively displaced, the printing result to be obtained is changed. When the platen roller  40  and the image forming portion (thermal head  30 ) are relatively located in the most appropriate positions, a preferable printed object (picture) is obtained. On the other hand, when the platen roller  40  and the image forming portion (thermal head  30 ) are not relatively located in appropriate positions, the printed result may be blurred or the ink ribbon T may be wrinkled. Such a wrinkle may be transferred onto a picture. 
     In the embodiment, the image forming portion (thermal head  30 ) moves in the transport directions (feeding direction D 1 , drawing back direction D 2 ), so that the image forming portion is positioned in the transport directions (feeding direction D 1 , drawing back direction D 2 ) relative to the platen roller  40 . The platen roller  40  and the image forming portion (thermal head  30 ) can be thereby relatively aligned with a simple configuration. 
     The platen roller  40  is regulated from moving in the transport direction (feeding direction D 1 , drawing back direction D 2 ), The parallelism of the platen roller  40  and the transport roller (driving roller  21 , driven roller  23 , counter roller  22 ) can be therefore maintained. As a result, the meandering and the wrinkle of the sheet S and the ink ribbon T and the printing error such as color shit can be prevented. 
     Since the platen roller  40  can be attached to the same casing  2  as the transport rollers (driving roller  21 , driven roller  23 , counter roller  22 ), the parallelism of the platen roller  40  and the transport roller (driving roller  21 , driven roller  23 , counter roller  22 ) can be easily maintained. 
     The printer  1  of the embodiment includes the regulating member  32  having the first regulating portion  32   a  that extends in the directions (direction F 1 , direction F 2 ) substantially vertical to the transport directions (feeding direction D 1 , drawing back direction D 2 ), and regulates the movement of the image forming portion (thermal head  30 ) ( FIG. 4 ). 
     The image forming portion (thermal head  30 ) can be positioned relative to the platen roller  40  in the transport directions (feeding direction D 1 , drawing back direction D 2 ) with a simple configuration. The platen roller  40  and the image forming portion (thermal head  30 ) can be thereby aligned with a simple configuration. 
     In the embodiment, the position of the regulating member  32  in the transport directions (feeding direction D 1 , drawing back direction) is adjustable. 
     The image forming portion (thermal head  30 ) includes individual differences in its properties due to production tolerances. The most appropriate relative position of the platen roller  40  and the image forming portion (thermal head  30 ) differs for each image forming portion (thermal head  30 ). 
     In the embodiment, when the image forming portion (thermal head  30 ) is assembled, the position of the regulating member  32  in the transport directions (feeding direction D 1 , drawing back direction D 2 ) can be adjusted according to the properties of the image forming portion (thermal head  30 ). The most appropriate relative position of the platen roller  40  and the image forming portion (thermal head  30 ) can be adjusted according to the properties of the image forming portion (thermal head  30 ). 
     The printer  1  of the embodiment includes the first biasing member (tension spring  38 ) that biases the image forming portion (thermal head  30 ) in the direction in which the sheet S is transported (drawing back direction D 2 ) among the transport directions (feeding direction D 1 , drawing back direction D 2 ) when the image is formed on the sheet S. The first regulating portion  32   a  regulates the image forming portion (thermal head  30 ) from moving in the biasing direction by the first biasing member (tension spring  38 ) ( FIG. 4 ). 
     The biasing direction by the first biasing member (tension spring  38 ) thereby becomes the same as the direction in which the sheet S is transported (drawing back direction D 2 ) when the image is formed on the sheet S. With a frictional force which occurs in the image forming portion (thermal head  30 ) by the transport of the sheet S, a force direction applied to the image forming portion (thermal head  30 ) becomes a direction which is the same as the biasing direction by the first biasing member (tension spring  38 ). As a result, the image forming portion (thermal head  30 ) can be regulated to the platen roller  40  without the influence of the transport of the sheet S. 
     In the printer  1  of the embodiment, the regulating member  32  is attached to the image forming portion (thermal head  30 ), and the first regulating portion  32   a  contacts the bearing  41  attached to the platen roller  40  outside the sheet S in the width direction ( FIG. 5 ). 
     The image forming portion (thermal head  30 ) can be thereby positioned relative to the platen roller  40  without disturbing the transport of the sheet S. 
     Although the printer of the present disclosure is described as above based on the embodiment, the specific configurations are not limited to the embodiment. Any change in the design, addition, and the like are allowed as long as they do not depart from the scope of the invention according to each claim. 
     The embodiment describes the example that regulates the movement of the thermal head  30  in the transport direction by the first regulating portion  32   a.  However, a mechanism capable of slightly adjusting the movement of the thermal head  30  in the transport direction can be provided. 
     The embodiment describes the example that uses the photographic paper as the sheet S. However, the sheet is not limited to the photographic paper, and, for example, plain paper may be used. 
     The embodiment describes the example that uses the tension spring  38  as the first biasing member. However, the first biasing member is not limited to the tension spring. 
     The embodiment describes the example in which the present disclosure is applied to the sublimation type thermal transfer printer  1 . However, the present disclosure is applicable to another thermal type printer.