JP4968347B2 - Printer and paper holding mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact paper feeding mechanism for a printer suitably used when an energizing mechanism for energizing a paper presser roller to a paper feed roller using a torsion spring or a coil spring cannot be used. <P>SOLUTION: The paper feeding mechanism for the printer includes the paper feed roller, the paper presser roller, and a torsion bar 27 energizing the paper presser roller to the paper feed roller. The torsion bar 27 is formed, by bending a torsion bar material of circular cross section, with linear portions 271, 272, both end latching arms 274, 275 to which force for generating torsion to the linear portions is applied, and a roller shaft presser portion 273 energizing a roller shaft 26a of the paper presser roller by twisting force generated to the linear portions. The latching arms 274, 275 are latched to the body frame side of the printer. The roller shaft 26a of the paper presser roller 26 can thereby be energized by the roller shaft presser portion 273. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a paper feeding mechanism of a printer for conveying recording paper via a printing position, and more particularly, to a printer in which a mechanism for urging a paper pressing roller against a paper feeding roller is small and compact. The present invention relates to a paper feed mechanism.

  In a printer, for example, a printer for printing on a recording paper roll, the recording paper is fed out from the recording paper roll loaded in the recording paper roll storage unit and conveyed via the printing position, and a desired sheet is printed on the recording paper. Printing is performed. A paper feed mechanism for transporting recording paper generally includes a paper feed roller that is rotated by a paper feed motor, and a paper pressing roller that is biased by the paper feed roller, and the recording paper is sandwiched therebetween. The recording paper is conveyed by the rotation of the paper feed roller.

  As a mechanism for biasing the paper pressing roller to the paper feeding roller, a mechanism for biasing the roller shaft to the paper feeding roller by pulling the end of a turning lever attached to the end of the roller shaft of the paper pressing roller by a coil spring. For example, it is disclosed in Patent Document 1 below. A mechanism for directly pulling the roller shaft of the paper pressing roller with a coil spring is disclosed in Patent Document 2 below. Furthermore, a mechanism for biasing the roller shaft of the paper pressing roller to the paper feed roller by a torsion spring is also known.

JP-A-5-92627 JP-A-7-323623

  Here, in order to meet the demand for miniaturization and compactness of the printer, it is also important to miniaturize and compact such a paper feed mechanism.

  In particular, in a roll paper printer for printing on a recording paper roll mounted on a POS terminal or the like, there is a strong demand for downsizing and compacting the paper feeding mechanism. That is, as a roll paper printer, a platen and a paper feed roller facing the print head when opening the opening / closing lid of the recording paper roll storage section so that the roll paper replacement operation can be easily performed. Are also known to be configured to open together. In the case of this configuration, since it is necessary to incorporate a mechanism for urging the paper pressing roller so as not to interfere with the paper feed roller that opens and closes in the vertical direction, there may be a case where a sufficient space cannot be secured in the front-rear direction of the printer. In addition, an auto-cutter is generally arranged above the paper feed roller and paper presser roller (recording paper discharge side), so there is enough space to incorporate a mechanism to bias the paper presser roller above. There are cases where it is impossible Furthermore, when using an ink ribbon, it is necessary not to interfere with the mounting of the ribbon cassette, so there may be a case where a sufficient space for incorporating a mechanism for urging the paper pressing roller cannot be secured.

  In addition to this, a roll paper printer sometimes incorporates a mechanism that reads an index called a black mark printed on the back side of the recording paper roll and determines the cutting position of the recording paper roll based on this. is there. A sensor for reading an index is generally arranged at a side position of the paper feed roller and the paper pressing roller. In this case, a mechanism for applying an urging force by extending the end of the roller shaft of the paper pressing roller laterally cannot be attached.

  An object of the present invention is to propose a paper feeding mechanism for a small and compact printer in view of such a point.

  Another object of the present invention is to propose a printer having such a small and compact paper feed mechanism.

In order to solve the above problems, a paper feed mechanism of a printer according to the present invention is a printer having an open / close frame that is attached to be openable and closable around a rotation axis of a rear end portion of a main body frame on which a print head is mounted. A paper holding mechanism,
As the paper pressing mechanism,
The open / close frame has a paper feed roller together with a conveyance guide that forms one of the conveyance paths of the recording paper.
Equipped with
A guide that forms the other of the transport path on the main body frame so as to face the transport guide
A roller mounting plate including a plate portion, a paper pressing roller mounted on the roller mounting plate, and the paper
A torsion bar for pressing and pressing the pressing roller against the paper feed roller;
Equipped with
The torsion bar has a straight portion and a force that generates torsion in the straight portion.
The first folding portion and the torsional force generated in the linear portion.
A second bent portion pressing and energizing the roller,
The paper pressing roller is divided into a plurality of roller bodies, and the paper feeding roller and the paper pressing roller are automatically aligned so that the second bent portion of the torsion bar is sandwiched between them. It is characterized by.

  The torsion bar is bent, and the paper pressing roller is urged by a straight portion, a first bent portion where a force for generating a twist is applied to the straight portion, and a twisting force generated in the straight portion. What is necessary is just to make it the shape provided with the 2nd bending part which is doing.

  By using the torsion bar, the urging mechanism of the paper pressing roller can be configured even when there is no space for installing the torsion spring or the coil spring.

  Here, if bending occurs in the linear portion of the torsion bar, the urging force of the paper pressing roller using torsional force is reduced, so that the linear portion of the torsion bar is not bent. It is desirable to have a supporting torsion bar support member.

  In this case, the torsion bar support member has a plurality of torsion bar insertion grooves into which the linear portions can be inserted so that the torsion bar can be attached to the torsion bar support member by a simple operation. desirable.

  Further, if a hooking portion on which the first bent portion is hooked is formed on the torsion bar support member, it is not necessary to arrange another member having the hooking portion, so that the paper feeding mechanism can be made compact. Can be configured.

  Next, the paper pressing roller includes a roller shaft and at least two roller bodies supported coaxially with the roller shaft, and the second bent portion of the torsion bar is formed on the roller body. It can be set as the structure which urged | biased the part of the said roller shaft located in between. By urging the roller shaft portions between the roller bodies, these roller bodies can be equally urged against the corresponding paper feed rollers.

  On the other hand, the torsion bar support member and the roller shaft support member that supports both end portions of the roller shaft of the paper pressing roller so as to be slidable toward and away from the paper feed roller can be used. . By making these into a single member, the number of parts of the paper feed mechanism can be reduced.

Next, a reference example is a printer provided with the paper pressing mechanism having the above-described configuration, which opens and closes with respect to the main body frame, a print head attached to the main body frame, and the main body frame with the rear end portion as a center. Closing the opening / closing frame, a platen attached to a tip portion of the opening / closing frame, the paper pressing roller attached to a position above the print head in the main body frame, and the opening / closing frame And the paper feed roller attached to a position above the platen in the opening / closing frame so as to be in contact with the paper pressing roller.

  In a printer having this configuration, the installation space for the paper feed mechanism is often limited. However, the paper feed mechanism according to the present invention is small and compact, and thus is suitable for incorporation in the printer.

  Some printers with this configuration are provided with a cutting blade for cutting the recording paper fed by the paper feed roller. In this case, it is desirable to use the cutting blade holder to which the cutting blade is attached as the roller shaft support member and the torsion bar support member. Thus, by using three parts as a single part, the number of parts can be reduced, and the paper feed mechanism and the printer can be reduced in size and size.

Further, the printer of the reference example has a recording paper roll storage portion formed on the main body frame side, and an opening / closing lid for opening and closing the storage portion, and the opening / closing lid is attached to the opening / closing frame. Can be configured.

  Furthermore, it has a recording paper conveyance path that guides the recording paper from the storage section to the cutting position by the cutting blade via the printing position by the print head, and the recording paper conveyance path opens the opening and closing frame, It can be set as the structure formed between the said opening-and-closing frame and the said main body frame so that it may be in an open state.

  Further, the print head may be of a dot impact type, and the main body frame may be configured such that a ribbon cassette mounting portion on which a ribbon cassette can be mounted is disposed from above.

  As described above, in the printer of the present invention, the paper pressing roller is urged against the paper feed roller using the torsion bar. By bending the torsion bar, the linear portion, the first bent portion on which a force that generates torsion acts on the linear portion, and the paper pressing roller are attached by the torsional force generated on the linear portion. If the second bent portion is formed, the first bent portion is hooked on the frame side of the printer, so that the roller shaft of the paper pressing roller can be biased by the first bent portion. it can. Therefore, according to the present invention, the urging mechanism can be made compact and compact when, for example, a torsion spring or a coil spring cannot be used as the urging mechanism of the paper pressing roller.

  Further, in the present invention, since the linear portion of the torsion bar is supported so as not to bend, the roller shaft of the paper pressing roller can be reliably urged using the torsional force of the linear portion.

  Furthermore, in the present invention, the torsion bar support member to which the torsion bar is attached is formed with a plurality of torsion bar insertion grooves into which the linear portions can be inserted, so that the torsion bar attaching operation is simplified.

  Furthermore, in the present invention, the roller shaft of the paper pressing roller is slidably supported, and the roller shaft portion between the paper pressing rollers is urged by the torsion bar. According to this configuration, it is possible to form a state in which each portion is pressed with a uniform urging force while the paper pressing roller is parallel to the paper feeding roller.

1 is an external perspective view of a printer to which the present invention is applied. It is a schematic longitudinal cross-sectional view of the printer of FIG. It is a schematic longitudinal cross-sectional view in the state which opened the opening-and-closing lid | cover in the printer of FIG. FIG. 2 is a partial enlarged cross-sectional view showing a paper feed mechanism portion of the printer of FIG. FIG. 2 is a perspective view showing a printer unit built in the printer of FIG. 1. FIG. 6 is a perspective view showing a state where the open / close side unit is opened in the printer unit of FIG. 5. FIG. 2 is a perspective view when a paper feeding mechanism portion attached to a fixed side unit in the printer of FIG. 1 is viewed from the rear side of the printer. It is a perspective view at the time of seeing the part shown in FIG. 7 from the printer front side. It is a perspective view which shows the roller mounting plate in FIG. It is a perspective view which shows the torsion bar in FIG.

  Embodiments of a printer to which the present invention is applied will be described below with reference to the drawings.

(overall structure)
FIG. 1 is an external perspective view of the printer according to the present embodiment, FIG. 2 is a schematic vertical cross-sectional view thereof, FIG. 3 is a schematic vertical cross-sectional view in a state where an opening / closing lid is opened, and FIG. It is a partial expanded sectional view which shows the part of a paper feed mechanism.

  Referring to these drawings, the printer 1 includes a rectangular frame-shaped case body 2 that covers the four sides of the printer, a front opening / closing lid 3 that covers the front portion of the upper surface of the printer, and a rear opening / closing lid 4 that covers the rear portion. These constitute a printer case. A printer unit 11 is built in the printer case, and a recording paper discharge port 5 is formed between the opening / closing lids 3 and 4. When the slide button 6 is operated, the rear opening / closing lid 4 is released from its locking mechanism (not shown) and can be opened as shown in FIG. When the opening / closing lid 4 is opened, the storage section 8 for the recording paper roll 7 in the printer unit 11 is exposed, and the recording paper roll 7 can be replaced. When the front opening / closing lid 3 is opened, the ribbon cassette mounting portion 10 for detachably mounting the ribbon cassette 9 of the ink ribbon of the printer unit 11 is exposed so that the ribbon cassette 9 can be replaced.

  Next, the internal structure of the printer will be described. A storage portion 8 for a recording paper roll 7 having an arc-shaped bottom surface opened upward when viewed from the side is formed in a rear portion of the printer unit 11. The recording paper 7 a drawn out from the recording paper roll 7 loaded here is guided to the recording paper conveyance path 15 via the guide roller 14 arranged at the front end portion of the storage portion 8. The recording paper conveyance path 15 includes a conveyance path portion 16 slightly inclined upward toward the front, a front inclination path portion 17 rising from the front end of the conveyance path portion 16 at a large inclination angle, A rear ramp portion 18 that is inclined rearward from the upper end of the front ramp portion 17 and connected to the recording paper discharge port 5 is provided. 2 and 4, the recording paper 7a is indicated by a one-dot chain line.

  The conveyance path portion 16 is defined by a conveyance guide 16a and a conveyance surface 16b facing the conveyance guide 16a. The subsequent forward slope portion 17 is defined by the head surface 20a of the dot impact type print head 20 and the platen 21 facing the print head 20 at a constant interval. It has become. The print head 20 is disposed so that the head surface 20a faces rearward and faces upward. Corresponding to the inclination of the print head 20, the surface of the platen 21 is arranged in a state inclined downward toward the front. The print head 20 is mounted on a head carriage 22, and the head carriage 22 can reciprocate in the width direction along the carriage guide shaft 23.

  A mounting portion 10 for the ribbon cassette 9 is formed on the upper side of the head carriage 22. The mounting portion 10 is also inclined and arranged so as to be directed upward toward the rear. Accordingly, the ink ribbon 9a of the ribbon cassette 9 mounted here can be set between the print head 20 and the platen 21 so as to be parallel to them.

  A rear ramp portion 18 that is continuous with the front ramp portion 17 is defined by a conveyance guide 28 that extends in a direction bent rearward from the upper end of the platen 21. A paper feed mechanism including a paper feed roller 25, a paper press roller 26, and a torsion bar 27 as a biasing member that biases the paper press roller 26 toward the paper feed roller 25 is provided in the rear inclined path portion 18. Is arranged. The paper feed roller 25 is disposed on the rear side of the rear slope portion 18, and the paper pressing roller 26 is movable on the front side in a direction approaching the paper feed roller 25 with respect to the roller mounting plate 29 (roller shaft support member). And is always urged toward the paper feed roller 25 by the spring force of the torsion bar 27.

  The recording paper 7 a pulled out from the recording paper roll 7 is sandwiched between the paper feeding roller 25 and the paper pressing roller 26, and is conveyed along the conveying path 15 by rotating the paper feeding roller 25 by a driving source (not shown). Is done. In this example, the platen 21 and the conveyance guide 16a continuous below the platen 21 are formed by a single platen frame 55, and the conveyance guide 28 is attached to the upper end portion of the platen frame 55. .

  Next, a vertical automatic cutting unit 30 for cutting the recording paper is disposed in the vicinity of the recording paper discharge port 5. The automatic cutting unit 30 includes a fixed blade 31 disposed on the front side, a movable blade 32 disposed on the rear side, and a drive mechanism 33 for operating the movable blade 32 across the conveyance path of the recording paper. Yes. The movable blade 32 and the drive mechanism 33 are built in the case 34. The recording paper 7 a between the fixed blade 31 and the movable blade 32 is cut when the movable blade 32 slides on the upper surface of the fixed blade 31. Further, a cutting blade 35 capable of cutting the recording paper by manual operation is attached to the front edge portion of the recording paper discharge port 5.

(Printer unit)
FIG. 5 is a perspective view showing the printer unit 11 built in the printer case, and FIG. 6 is a perspective view showing a state in which the open / close side unit is opened. The printer unit 11 includes a fixed side unit 12 and an open / close side unit 13, and the open / close side unit 13 is supported by the fixed side unit 12 so as to be rotatable up and down around the rear end portion.

  In the printer unit 11 of this example, when the opening / closing lid 4 of the storage unit 8 of the recording paper roll is opened in order to easily perform the replacement operation of the recording paper roll 7, the recording paper conveyance having the above-described configuration is performed. The path 15 is also configured to be in an open state. For this purpose, the components on one side constituting the conveyance path 15 are attached to the fixed side unit 12, and the opening / closing lid 4 and the other side constituting the conveyance path 15 are attached to the opening / closing side unit 13 on the moving side. When the side components are attached and the open / close unit 13 is opened, the storage section 8 of the recording paper roll 7 is opened, and at the same time, the transport path 15 is opened.

  More specifically, the recording unit 8 for the recording paper roll, the conveyance surface 16b of the conveyance path portion 16, the print head 20, the paper pressing roller 26, and the fixed blade 31 of the automatic cutting unit 30 are attached to the fixed side unit 12. Yes. On the other hand, the open / close side unit 13 includes a platen frame 55 (conveyance guide 16a, platen 21) and a guide plate 28 that define the conveyance path portion 16, the front ramp portion 17 and the rear ramp portion 18. The paper feed roller 25, the movable blade 32 of the automatic cutting unit 30, and the drive mechanism 33 are attached. An open / close lid 4 is also attached (see FIG. 3).

  Here, even when the movable blade 32 is in a cut state due to some failure, that is, when the movable blade 32 is stopped in a crossed state with the fixed blade 31, the movable blade 32 is located above the fixed blade 31, The opening / closing unit 13 is movable.

  As can be seen from FIGS. 3 and 6, when the opening / closing unit 13 is fully opened, the recording paper roll 7 can be loaded by a simple operation of dropping the recording paper roll 7 into the storage unit 8 from above. In addition, since the transport path 15 is in an open state, the operation of placing the recording paper 7a pulled out from the recording paper roll 7 along the transport path 15 is extremely simple. Further, when the opening / closing unit 13 is closed and returned to the state shown in FIGS. 2, 4, and 5, the recording paper 7 a passes between the print head 20 and the platen 21, and between the paper feed roller 25 and the paper pressing roller 26. A state of being pulled out from the recording paper discharge port 5 is automatically formed.

  Next, the structures of the fixed side unit 12 and the open / close side unit 13 will be described in more detail. First, the fixed side unit 12 includes a main body frame 40, and a carriage guide shaft 23 is stretched across the front side portion of the main body frame 40 in the width direction. As described above, the head carriage 22 on which the print head 20 is mounted is supported on the carriage guide shaft 23 so as to be capable of reciprocating. A ribbon frame 41 is attached so as to cover the head carriage 22 and the print head 20, and an outer peripheral portion of the ribbon frame 41 serves as a mounting portion 10 for the ribbon cassette 9.

  A storage portion 8 for loading the recording paper roll 7 is formed at a rear portion of the main body frame 40, and a rotation center shaft 43 extending in the width direction is formed at the rear end portion of the storage portion 26. 40. The rotation center shaft 43 is the rotation center of the opening / closing unit 13.

  On the other hand, the open / close side unit 13 has an open / close frame 51. The open / close frame 51 has a front end that connects left and right arm portions 52, 53 extending in the front-rear direction and front end portions of the arm portions 52, 53. And a connecting plate portion 54. The rear end portions of the left and right arm portions 52 and 53 are rotatably supported by both end portions of the rotation center shaft 43. A platen frame 55 (platen 21, conveyance guide 16a) and a conveyance guide 28 are attached to the front end of the front end connecting portion 54 of the opening / closing frame 51, and a paper feed roller shaft 25a is attached to the back side thereof. From the opening 28a formed in the guide plate 28 in the platen frame 55, the outer peripheral surfaces of the two paper feed roller bodies 25b fixed coaxially to the paper feed roller shaft 25a protrude forward. The movable blade 32 and the drive mechanism 33 of the automatic cutting unit 30 are mounted on the front end connecting plate portion 54 of the opening / closing frame 51.

  Here, as can be seen from FIGS. 2 and 3, in the fixed side unit 12 of this example, the print head 20 is inclined so as to face upward as described above, and is mounted so as to correspond to this. The ribbon cassette 9 attached to the part 10 is also inclined and arranged in the same direction. On the opening / closing unit 13 side, the platen 21 is inclined so as to face downward so as to face the head surface 20a of the print head 20 in parallel at a constant interval. In addition, the rotational position of the opening / closing unit 13, that is, the height position of the central axis of the rotation center shaft 43 is lower than the head surface 20 a of the print head 20.

  As a result, the movement trajectory of the opening / closing unit front end portion associated with opening / closing of the opening / closing unit 13, that is, the movement trajectory of the upper end and the lower end of the platen 21 facing the print head 20 faces the print head 20 at regular intervals. This is an arc that moves away from the forward position (position where the open / close side unit 13 is closed) to the head surface 20a of the print head 20 instead of forward or upward, and when the open / close side unit 13 is opened or closed. These movement trajectories do not intersect the print head 20.

  Further, since the rotation center line of the opening / closing unit 13 (center line of the rotation center shaft 43) is located below the head surface 20a of the print head 20, the movement trajectory of the upper and lower ends of the platen 21 is the opening and closing. The amount of backward movement accompanying the movement of the side unit 13 is large. As a result, a space that does not cover the movement locus of the opening / closing unit 13 (an inverted triangular space when viewed from the side) is formed immediately above the printing position 17. In this example, using this space, the paper pressing roller 26, the torsion bar 27, the fixed blade 31 of the automatic cutting unit 30, the cutting blade 35 and the like are arranged. Therefore, the apparatus configuration can be made small and compact.

  Further, in the present example, the mounting portion 10 of the ribbon cassette 9 is also tilted in association with the print head 20 being tilted. As a result, the ribbon cassette 9 is attached to and detached from the mounting portion 10 in an oblique direction from the upper front side. The paper pressing roller 26, the fixed blade 31 of the automatic cutting unit 30, and the cutting blade 35 are disposed directly above the printing position 17, but the ribbon cassette 9 can be attached and detached without being obstructed by these. Therefore, there is an advantage that the ribbon cassette 9 can be attached and detached with one touch.

  Furthermore, by adjusting one or both of the inclination angle of the print head 20 and the platen 21 and the height position of the rotation center shaft 43 of the opening / closing unit 13, the movement locus of the opening / closing unit 13 can be changed. As a result, it is possible to increase or decrease the space that is not applied to the movement trajectory of the upper and lower ends of the platen formed immediately above the printing position 17, and there is also an advantage that the degree of automatic component layout is increased.

(Paper feed mechanism)
Next, the paper feed mechanism of the printer 1 will be described in detail with reference to FIGS. FIG. 7 is a perspective view when a portion including the paper pressing roller 26, the torsion bar 27, the roller mounting plate 29, the fixed blade 31 and the cutting blade 35 attached to the fixed side unit 12 is viewed from the rear side of the printer. FIG. 8 is a perspective view of the portion shown in FIG. 7 as viewed from the front side of the printer. FIG. 9 is a perspective view showing the roller mounting plate 29, and FIG. 10 is a perspective view showing the torsion bar 27.

  The roller mounting plate 29 of this example includes a guide plate portion 61 facing the guide plate 28 substantially in parallel. A horizontal plate portion that is bent in front of the printer and extends horizontally at the upper end of the guide plate portion 61. 62 is continuous. Further, a vertical plate portion 63 that is bent upward and extends vertically is continued at the front end of the horizontal plate portion 62, and a cutting blade that is bent rearward of the printer and extends horizontally at the upper end of the vertical plate portion 63. The holding plate portion 64 is continuous. The rear end portion of the cutting blade holding plate portion 64 is bent obliquely rearward, and the cutting blade 35 is integrally formed at the upper end of this portion.

  In the roller mounting plate 29 having this configuration, both ends of the horizontal plate portion 62 are bridged over the upper end portions of the left and right side plate portions 44 and 45 (see FIG. 6) of the main body unit 40 of the fixed side unit 12. It is fixed to the part.

  The guide plate portion 61 of the roller mounting plate 29 is formed with two horizontally elongated openings 65 and 66 in the right half portion, and two rollers of the paper pressing roller 26 are respectively provided from these openings 65 and 66. The outer peripheral surfaces of the main bodies 26b and 26b protrude by a predetermined amount toward the rear side of the printer. These roller bodies 26b and 26b are respectively urged by the elastic force of the torsion bar 27 against the two roller bodies 25b and 25b of the paper feed roller 25 located on the rear side of the printer (see FIG. 4). ). On the front surface of the guide plate portion 61, roller bearing portions 67 and 68 formed by cutting and raising the outer ends of the openings 65 and 66 to the front side of the printer are formed. In the roller bearings 67 and 68, long oval bearing holes 67a and 68a are formed on the paper feed roller 25 side. In these bearing holes 67a and 68a, both ends of the roller shaft 26a on which the roller main bodies 26b and 26b of the paper pressing roller 26 are rotatably supported are inserted in a slidable state.

  Next, a torsion bar 27 extending in the printer width direction is attached to the lower surface 62a of the horizontal plate portion 62 continuous with the upper end of the guide plate portion 61 in a state parallel to the lower surface 62a. The torsion bar 27 is formed by bending a torsion bar material having a circular cross section, and is bent into a U-shape in the downward direction formed between the left and right linear portions 271 and 272. Roller shaft pressing portion 273 (second bent portion), and latching arms 274 and 275 (first bent portion) formed by bending the outer ends of linear portions 271 and 272 downward at substantially right angles, It has.

  Insertion grooves 71, 72, 73 into which the torsion bar 27 can be inserted from the front side of the printer are formed on the lower surface 62a of the horizontal plate portion 62. The insertion groove 71 is for inserting the short linear portion 271, and the insertion grooves 72 and 73 are for inserting the long linear portion 272. These insertion grooves 71 to 73 are formed by cutting and raising the horizontal plate portion 62 to the lower surface 62a side and bending it to the printer front side. Further, pressers 74, 75, and 76 that press the torsion bar 27 to the rear side of the printer are also formed on the lower surface 62a of the horizontal plate portion 62. The holding portions 74 and 75 are in contact with the linear portions 271 and 272 from the front side of the printer, respectively. The pressing portion 76 is in contact with the bent portion of the roller shaft pressing portion 273 from the front side of the printer. These holding portions 74 to 76 are also formed by cutting and raising the horizontal plate portion 62 toward the lower surface 62a.

  When the torsion bar 27 is inserted into the insertion grooves 71 to 73 and attached to the lower surface 62a of the horizontal plate portion 62 so as to be in contact with the pressing portions 74 to 76 from the rear side of the printer, The position in the longitudinal direction and the vertical direction of the printer is determined. Further, since the straight portions 271 and 272 are sandwiched between the insertion grooves 71 to 73 and the pressing portions 74 and 75 from the front and rear direction, it is possible to prevent the straight portions 271 and 272 from being bent. Further, it is possible to form a state in which the roller shaft pressing portion 273 of the torsion bar 27 is pressed from the front side of the printer to the portion of the roller shaft 26a exposed from between the paper pressing rollers 26 and 26.

  Here, the latching arms 274 and 275 formed on the left and right ends of the torsion bar 27 are respectively in front of the printer with respect to the latching portions formed on the left and right side plate portions 44 and 45 of the fixed side unit 12. It is hooked from. FIG. 4 shows a latching portion 44 a formed on one side plate portion 44. The latching arms 274 and 275 are pressed against the latching portion by the elastic return force from the front side of the printer, and the roller shaft pressing portion 273 of the torsion bar 27 is in contact with the roller shaft 26a from the rear side of the printer. Accordingly, a torsional force acts on the left and right linear portions 271 and 272, and this torsional force acts as a biasing force for the roller shaft 26a. As a result, the roller main bodies 26b and 26b of the paper pressing roller 26 supported rotatably on the roller shaft 26a are urged by the predetermined elastic force to the roller main bodies 25a and 25a of the paper feed roller 25. It is formed.

  Further, the torsion bar 27 presses a portion of the roller shaft 26a between the left and right roller bodies 26b, 26b of the paper pressing roller 26, and the roller shaft 26a is slidable in a direction toward and away from the paper feed roller 25. It is supported. Therefore, even when the paper pressing roller 26 is not parallel to the paper feeding roller 25, the roller bodies 26b and 26b of the left and right paper pressing rollers 26 are automatically aligned so as to be parallel to the paper feeding roller 25, and the paper feeding roller 25 It is pressed against each roller body 25b, 25b with an equal pressing force.

  Thus, in the paper feeding mechanism of this example, the torsion bar 27 is used to urge the paper pressing roller 26 to the paper feeding roller 25. The torsion bar 27 includes linear portions 271 and 272, latching arms 274 and 275 at both ends where a force that generates torsion is applied to the linear portions 271 and 272, and a torsional force generated in the linear portion. Thus, a roller shaft pressing portion 273 that biases the roller shaft 26a of the paper pressing roller is formed.

  Therefore, the paper feeding mechanism of this example is effective when there is no space for attaching a torsion spring to the roller shaft 26a of the paper pressing roller 26, or when there is no space for attaching a coil spring or the like at both ends of the roller shaft 26a.

  For example, as indicated by imaginary lines in FIG. 8, optical sensors 81, 82, 83 for reading black marks printed on the surface of the recording paper 7a are provided on both sides of the paper pressing roller 26 in the guide plate portion 61. May be placed. In this case, the left and right ends of the roller shaft 26a are extended to the left and right ends of the fixed unit 12, and a member such as a coil spring for applying an urging force to the roller shaft 26a cannot be attached. In such a case, it is advantageous to employ an urging mechanism using the torsion bar 27 of this example.

  In this example, the roller mounting plate 29 is formed with mounting portions for the cutting blade 35 and the torsion bar 27 together with the roller bearing portions 67 and 68. Therefore, the number of parts of the paper feed mechanism can be reduced. Note that hooking portions for hooking the latching arms 274 and 275 of the torsion bar 27 can also be formed on the roller mounting plate 29.

  Further, the attachment portion of the torsion bar 27 formed on the roller attachment plate 29 is constituted by insertion grooves 71 to 73 in which the torsion bar 27 can be inserted and fixed from the front side of the printer. Therefore, the installation work of the torsion bar 27 is simple. Further, the straight portions 271 and 272 of the torsion bar 27 are supported by the insertion grooves 71 to 73 and the pressing portions 74 to 76 so as not to be bent. The pressing roller 26 can be urged.

  Furthermore, since the portion between the two roller bodies 26b, 26b in the roller shaft 26a that is slidably supported by the paper pressing roller 26 is urged, the paper pressing roller 26 as a whole has a uniform urging force. It can be pressed against the side of the paper feed roller 25, and troubles such as a one-sided contact state can be prevented.

  In this example, the two roller main bodies 26b and 26b are provided as the paper pressing roller 26, but three or more may be provided. In this case, two or more roller pressing portions 273 may be formed on the torsion bar 27 so that the portions of the roller shafts 26a located between these roller bodies can be urged.

(Other embodiments)
The above example relates to a printer having a dot impact type print head, but the present invention can be similarly applied to a printer using an ink jet head as a print head. Furthermore, the present invention can be applied to a printer using a contact type print head such as a thermal head.

  In the above example, the paper feed roller and paper pressing roller that make up the transport mechanism are located above the print head, but the transport mechanism is located below the print head (upstream of the transport path). Even in such a case, the present invention can be similarly applied.

DESCRIPTION OF SYMBOLS 1 Printer, 4 Opening / closing lid, 5 Recording paper discharge port, 7 Recording paper roll, 8 Recording paper roll storage part, 9 Ribbon cassette, 10 Ribbon cassette mounting part, 11 Printer unit, 12 Fixed side unit, 13 Opening / closing side unit , 15 Recording paper transport path, 16 Transport path section, 17 Front ramp path section, 18 Back ramp path section, 20 Print head, 20a Head surface, 21 Platen, 25 Paper feed roller, 25a Roller body, 26 Paper press roller, 26a Roller shaft, 26b Roller body, 27 Torsion bar, 271, 272 Linear part, 273 Roller pressing part, 274, 275 Hanging arm, 29 Roller mounting plate, 61 Guide plate part, 62 Horizontal plate part, 63 Vertical plate part, 64 Cutting blade holding plate part, 65, 66 Opening part, 67, 68 Roller bearing part, 67a, 68a Bearing hole 71-73 Torsion bar insertion groove, 74-76 Torsion bar holding part, 30 automatic cutting unit, 31 fixed blade, 32 movable blade, 33 drive mechanism, 35 cutting blade, 40 body frame, 43 rotation center shaft, 44, 45 Side plate portion, 44a latching portion, 51 Opening / closing frame, 52, 53 Left and right arm portions, 54 Front end connecting plate portion

Claims (2)

A paper pressing mechanism in a printer having an open / close frame attached to be openable / closable around a rotation axis of a rear end portion of a main body frame on which a print head is mounted,
As the paper pressing mechanism,
The open / close frame is equipped with a paper feed roller together with a conveyance guide that forms one of the conveyance paths of the recording paper,
The main body frame includes a roller mounting plate including a guide plate portion that faces the transport guide and forms the other of the transport path, a paper pressing roller mounted on the roller mounting plate, and the paper pressing roller. A torsion bar that presses and biases the feed roller;
Equipped with
The torsion bar presses and urges the paper pressing roller by a linear portion, a first bent portion where a force for generating a twist is applied to the linear portion, and a torsional force generated in the linear portion. A second bent portion,
The paper pressing roller is divided into a plurality of roller bodies so that the second bent portion of the torsion bar is sandwiched between the paper feeding roller and the paper pressing roller when the opening / closing frame is closed. A paper presser mechanism for a printer, characterized in that the paper is automatically aligned. The optical sensor for detecting a recording paper is arrange | positioned in the outer side of the roller main body of the divided | segmented said paper pressing roller with respect to the 2nd bending part of the said torsion bar, The 1st aspect is characterized by the above-mentioned. Paper holding mechanism of the printer.

Images