Patent Publication Number: US-11654703-B2

Title: Movable paper guide structure of a label printer

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present application is classified as the field for the structure of a label printer and particularly related to a design based on a movable paper guide structure on a label printer with which some risks such as a label sticker improperly peeled off, printing crooked and paper jam are avoided for smooth and reliable printing in case of a piece of printing paper pulled back. 
     2. Description of the Prior Art 
     As machinery equipment specially used in label printing, the label printer is good in specific applications and applicable to label paper different from ordinary one according to distinct properties like dimension, thickness or material of a piece of selected label paper for printing based on the thermo-induction principle with which a necessary pattern is generated on a piece of label paper contacted by a thermal printing head (TPH) as required. 
     As shown in  FIG.  3   , the printing process of a conventional label printer, which features a label paper roll  400 ′ including continuous paper and installed on a label printer as usual, illustrates one end of the label paper roll  400 ′ is guided to a printing area by a paper guide structure  100 ′ and a label sticker  410 ′ on the label paper roll  400 ′ pressed by a roller  500 ′ contacts with a print head  600 ′ for completion of printing of the label sticker  410 ′. 
     For sufficient pressure applied on the label sticker  410 ′ to be printed, the label sticker  410 ′ should be properly clamped by both the roller  500 ′ and the print head  600 ′ which is equipped with a spring at the back in general. However, the paper guide structure  100 ′ in the prior art is a fixed device which is criticized for the drawback of a displacement of the roller  500 ′ and the print head  600 ′ due to a distinct thickness of the label sticker  410 ′. Specifically, the paper guide structure  100 ′ has a tip  110 ′ at a fixed position. When a displacement of the roller  500 ′ and the print head  600 ′ due to the label sticker  410 ′ with a distinct thickness takes place, a gap d′ is generated between the fixed tip  110 ′ of the paper guide structure  100 ′ and the print head  600 ′. Moreover, when a segment of paper, which fails to be printed at first and needs to be reprinted correctly because of the gap d′, is pulled back or the label sticker  410 ′ designed as an RFID label sticker is pulled back for a rewrite step, the label sticker  410 ′ on the label paper roll  400 ′ is improperly peeled off by the tip  110 ′ of the paper guide structure  100 ′ or another failure such as printing crooked or paper jam occurs. 
     Accordingly, how to avoid the gap d′ between the paper guide structure  100 ′ and the print head  600 ′ for neither the label sticker  410 ′ improperly peeled off nor further problems such as printing crooked and paper jam is an issue deserving to be overcome by persons skilled in the art aggressively. In particular, label printer structure, printing quality and cost of a consumable, each of which is an issue worthy of attention, should be considered attentively. 
     SUMMARY OF THE INVENTION 
     The present application is to provide a movable paper guide structure of a label printer, which is based on a changed contact position of a print head and a roller to rotate automatically for no gap in between such that some problems such as label sticker improperly peeled off, printing crooked and paper jam are avoided. 
     The present application is further to provide a movable paper guide structure of a label printer, which is driven by a spring, a belt or a motor and applicable to a selected model for flexible installation as required. 
     The present application is further to provide a movable paper guide structure of a label printer, which features a simple structure for easy installation and eliminates printing-related issues without a significantly increasing cost. 
     To achieve the above and other goals, a movable paper guide structure of a label printer in a technical solution of the present application comprises a paper guide body and a movable unit. 
     The paper guide body, which is installed in a label printer including a roller and a print head, is used to guide a piece of printing paper for a forward movement along a designated printing route; the movable unit, which is movably installed on the paper guide body close to one end of the print head, adapts to a displacement of the roller and the print head because of a changed contact position and keeps approaching the print head for no gap between the tip of the movable unit and the print head. 
     Accordingly, the movable unit in the present disclosure is adjustable forthwith and close to the print head during a printing process such that the front end of the movable unit is not hit by a piece of printing paper which is being pulled back for no incidents such as a label sticker improperly peeled off, printing crooked and paper jam. 
     In the above mechanism, the movable unit is pivotally fitted to the paper guide body by a pivot and movably installed on the paper guide body close to one end of the print head. 
     The movable unit is mounted on the paper guide body with a spring, a belt or a motor and movably installed on the paper guide body close to one end of the print head. 
     The movable unit is characteristic of a sharp portion which gradually tapers toward one end of the print head and keeps abutting the print head in case of a displacement of the movable unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic perspective view for an installed position of a movable paper guide structure of a label printer; 
         FIG.  1   a    is a partial enlargement view for the movable paper guide structure of the label printer in  FIG.  1   ; 
         FIG.  2    is a schematic plane view for a movable paper guide structure of a label printer during a printing process; and 
         FIG.  3    is a schematic plane view for a fixed paper guide structure of a conventional label printer during a printing process. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS.  1 ,  1     a  and  2  for a movable paper guide structure of a label printer, which comprises a paper guide body  100  and a movable unit  200 . 
     The paper guide body  100  installed in a label printer  300  is used to guide a piece of printing paper  400  for a forward movement along a designated printing route wherein the piece of printing paper  400  fed into a printing area is pressed by a roller  500  mounted inside the label printer  300  and contacts with a print head  600  by which a pattern is printed on the piece of printing paper  400  and/or a label sticker  410  as required. 
     In an embodiment, the movable unit  200  is pivotally fitted to the front end of the paper guide body  100  by a pivot  210  and movably installed on the paper guide body  100  close to one end of the print head  600  such that the print head  600  is approached by the movable unit  200  during a rotary motion without generation of a gap. 
     According to the above structural composition, a movable paper guide structure of a label printer in the present disclosure is characterized in that the movable unit  200  rotates about the pivot  210  as a center of rotation such that the print head  600  is approached by the front end of the movable unit  200  without generation of a gap. In principle, the printing paper  400  in the present disclosure denotes a label paper roll on which a distinct type of label sticker  410  with a certain thickness is coated. When the label sticker  410  on the printing paper  400  is pressed by the roller  500  and contacts with the print head  600 , a displacement of the roller  500  and the print head  600  due to the label sticker  410  with a distinct thickness occurs. If this issue is not corrected properly, the printing paper  400  pulled back during a printing process probably collides with the front end of the movable unit  200  and is peeled off or other incidents such as printing crooked and paper jam take place. Accordingly, the movable unit  200  in the present disclosure shifts automatically by referring to a changed contact position of the roller  500  and the print head  600  such that the front end of the movable unit  200  is always close to the print head  600  effectively for neither the label sticker  410  improperly peeled off nor other problems such as printing crooked and paper jam. 
     Moreover, the movable unit  200  is characteristic of a sharp portion  220  forward tapering from the pivot  210  in shape such that the sharp portion  220  with good flexibility features an adjustable position based on a displacement of the roller  500  and the print head  600  and always abuts the print head. 
     In addition, the movable unit  200 , which is mounted on the paper guide body  100  with a spring, rotates automatically in case of a displacement of the roller  500  and the print head  600 ; alternatively, the movable unit  200  is driven by a belt, a motor or another equivalent mechanism for the same effect. In the present disclosure, a movable paper guide structure of a label printer is described with a label sticker  410  used in an embodiment and even applicable to an alternative printing mode without a label sticker  410 , for example, thermal transfer receipt printing, in which the movable unit  200  always abuts the print head  600  in structural design for fewest drawbacks like printing crooked. 
     While the preferred embodiments of the invention have been set forth for the purpose of disclosure, modifications of the disclosed embodiments of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention.