Platen roller support mechanism and printer

Abstract

To provide a support mechanism of a platen roller, which can prevent or suppress strength from deteriorating and enables a size corresponding to an axial direction of the platen roller to reduce.SOLUTION: A support mechanism 30 of a platen roller 81 comprises a shaft member 31 arranged in parallel with the platen roller 81 and engagement members 32 and 33 provided at both end parts of the shaft member 31. The engagement members 32 and 33 can rotate with the shaft member 31 as a center, between an engaging position where the members engage with a platen unit 80 being fitted to a frame 10 to support the platen roller 81 at a predetermined position and a releasing position where the engagement thereof with the platen unit 80 is released, and surfaces 32g and 33g which are orthogonal to each other in an axial C2 direction (a width direction W) of the shaft member 31 of the engagement members 32 and 33 are formed as guide surfaces for regulating a position in the width direction of a sheet 200.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a support mechanism for a platen roller and a printer. [Background technology]

[0002] Printers that print on paper using a thermal head are equipped with a platen roller as a component responsible for feeding the paper and pressing it against the thermal head. The platen roller needs to be supported in a predetermined position relative to the thermal head during printing. For this reason, printers are equipped with a support mechanism that supports the platen roller in a predetermined position at both axial ends of the platen roller by engaging with the shaft of the platen roller itself or with a platen unit having a holder that rotatably holds the platen roller (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4093876 Summary of the Invention [Problem to be solved by the invention]

[0004] On the other hand, the paper on which the thermal head prints needs to be positioned appropriately in the width direction when it is fed to the position where the thermal head and the platen roller are in pressure contact, so paper regulating members that regulate the width direction position of the paper are provided near both ends of the paper in the width direction.

[0005] In this way, near both ends of the platen roller, a support mechanism is provided on the outside in the axial direction, and a paper regulating member is provided on the inside in the axial direction, with the support mechanism and the paper regulating member arranged side by side along the axial direction. Therefore, the size of the printer in the axial direction of the platen roller takes into account at least the thickness of the support mechanism and the thickness of the paper regulating member, which creates the problem that it is difficult to reduce the size of the printer in the axial direction.

[0006] Even if it were possible to reduce the size of the printer corresponding to the axial direction of the platen roller by reducing the thickness (the length along the axial direction of the platen roller) of the support mechanism or paper regulating member, in this case another problem could arise in that the strength of the support mechanism or paper regulating member would be reduced.

[0007] The present invention has been made in consideration of the above circumstances, and has an object to provide a support mechanism for a platen roller and a printer that can prevent or suppress a decrease in strength and reduce the size of the printer corresponding to the axial direction of the platen roller. [Means for solving the problem]

[0008] A first aspect of the present invention is a support mechanism for a platen roller that supports the platen roller by pressing it against a print head at the predetermined position when a platen roller or a platen unit including a holder that holds the platen roller and is detachable from a base member is attached to the base member, the support mechanism having a shaft member that is arranged parallel to the platen roller and engaging members provided at both ends of the shaft member, the engaging members being rotatable between an engaging position where the engaging members engage with the platen roller or the platen unit when attached to the base member to support the platen roller at the predetermined position and a releasing position where the engaging members are released from the platen roller or the platen unit, and a surface of the engaging members that intersects with the longitudinal direction of the shaft member is formed as a guide surface that regulates the width direction position of a paper transported between the print head and the platen roller.

[0009] A second aspect of the present invention is a printer comprising: a print head supported by a base member; a platen unit including a platen roller or a holder that holds the platen roller and is detachable from the base member; and a platen roller support mechanism according to the present invention that supports the platen roller in a predetermined position. Effect of the Invention

[0010] The platen roller support mechanism and printer according to the present invention can prevent or suppress a decrease in strength, and can reduce the size of the printer corresponding to the axial direction of the platen roller. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a perspective view showing an integrated printer including a support mechanism for a platen roller. [Diagram 2] 2 is a perspective view showing a state in which a platen unit is removed from the printer in FIG. 1. [Diagram 3] 2. FIG. 3 is a perspective view equivalent to FIG. 2, seen from a different direction than FIG. [Figure 4] FIG. 4 is an exploded perspective view showing the configuration of a support mechanism. [Diagram 5] 5 is a perspective view of one of the engagement members as viewed from the opposite direction to that of FIG. 4. FIG. [Figure 6] 5 is a perspective view of the other engaging member as viewed from the opposite direction to that of FIG. 4. FIG. [Figure 7] FIG. 2 is a front view of the printer as viewed from the front side of FIG. [Figure 8] 8 is a cross-sectional view taken along the line AA in FIG. 7, showing a state in which the engaging claw of the engaging member is engaged with an engaged portion formed on a holder of the platen unit to support the platen roller in a predetermined position. [Figure 9] 8 is a cross-sectional view taken along the line BB in FIG. 7. [Figure 10] 8 is a cross-sectional view taken along line CC in FIG. 7. [Figure 11]8, showing a state in which the engaging member is in a released position where it is disengaged from the platen unit after rotating counterclockwise about axis C2 and the engaging claw is disengaged from the engaged portion. FIG. [Figure 12] 8, showing a state in which the engaging member has further rotated counterclockwise about axis C2 from the state shown in FIG. 11, and the push-up portion of the engaging member has pushed upward the holder, which has been released from engagement with the engaging member, thereby moving the platen roller from its predetermined position. [Figure 13] 13 is a cross-sectional view corresponding to FIG. 8, illustrating a state in which the platen unit has been moved upward and removed from the side plate from the state illustrated in FIG. 12. [Figure 14] 13 is a partial perspective view showing a stopper portion formed on an engagement member. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a support mechanism for a platen roller and a printer according to the present invention will be described with reference to the accompanying drawings.

[0013] <Configuration> FIG. 1 is a perspective view showing an integrated printer 100 (hereinafter simply referred to as printer 100) including a support mechanism 30 for a platen roller 81, FIG. 2 is a perspective view showing the printer 100 in FIG. 1 with the platen unit 80 removed, and FIG. 3 is a perspective view equivalent to FIG. 2, seen from a different direction than FIG. 2.

[0014] The printer 100 shown in Fig. 1 is one embodiment of the printer according to the present invention, and is a printer to be built into various devices for use. Devices in which the printer 100 can be built include, but are not limited to, cash registers used for accounting in stores and ticket issuing machines for various tickets.

[0015] 1 to 3, the printer 100 includes a frame 10, a thermal head 20 (an example of a print head), a platen unit 80, and a support mechanism 30. The frame 10 includes a connecting member 13 (see FIG. 4) extending in the width direction W, and side plates 11 and 12 provided on both ends of the connecting member 13.

[0016] The frame 10 is an example of a base member, and the base member does not mean a member that serves as a reference, but simply means a member that directly or indirectly supports the thermal head 20 or fixes it to a fixed position. Therefore, the base member is not limited to the frame 10, and may be a support plate 21 that directly supports the thermal head 20, a housing that indirectly fixes the thermal head 20 to a fixed position, a guide plate 39 that is always in a fixed position relative to the thermal head 20, or the like.

[0017] 2 and 3, the thermal head 20 is supported at both ends in the longitudinal direction by the side plates 11 and 12 and at its back surface by the support plate 21, and is disposed so that its longitudinal direction is parallel to the width direction W. The thermal head 20 is capable of slight tilting about an axis connecting the portion supported by the side plate 11 and the portion supported by the side plate 12.

[0018] The thermal head 20 is biased (pushed) toward one end of this tiltable range by the elastic force of a torsion spring (not shown) and is pressed against a platen roller 81, which is supported by a frame 10 (described below). In a state where the thermal head 20 is pressed against the platen roller 81, the thermal head 20 performs thermal printing on the paper 200 transported between the platen roller 81 and the platen roller 81. The thermal head 20 can tilt within this tiltable range against the elastic force of the torsion spring.

[0019] A flexible flat cable 25 is connected to the thermal head 20 , and the thermal head 20 generates heat in response to a signal input from a controller (not shown) through the flexible flat cable 25 to the thermal head 20 , thereby printing on the paper 200 .

[0020] The platen unit 80 includes a platen roller 81 and a holder 82. The platen roller 81 is formed in a cylindrical shape with shafts 81a, 81b protruding from both ends of the cylinder. The holder 82 supports the shafts 81a, 81b of the platen roller 81 and holds the platen roller 81 rotatably. The platen unit 80 may include a cutter device that cuts the paper 200, but the platen unit 80 of this embodiment does not include a cutter device.

[0021] A recess 82a is formed in the lower portion of the holder 82, which corresponds to the movable range of the engaging claws 32e, 33e of the engaging members 32, 33 of the support mechanism 30 described later, and engaged portions 82b, 82b with which the engaging claws 32e, 33e respectively engage are formed in the recess 82a (FIG. 8). The engaged portions 82b will be described in detail later.

[0022] In the platen unit 80, one shaft portion 81a of the platen roller 81 protruding from both sides of the holder 82 is supported in a notch 11a in the side plate 11 of the frame 10, and the other shaft portion 81b is supported in a notch 12a in the side plate 12. As a result, the platen unit 80 is attached to the frame 10 with the axis C1 of the platen roller 81 parallel to the width direction W. At this time, the platen roller 81 is also rotatable relative to the frame 10.

[0023] The notch 11a of the side plate 11 is formed to be open toward the top of the side plate 11, and the notch 12a of the side plate 12 is formed to be open toward the top of the side plate 12. Therefore, by moving the shaft portion 81a supported in the notch 11a and the shaft portion 81b supported in the notch 12a upward, the shaft portions 81a, 81b are disengaged from the notches 11a, 12a, respectively, and the platen unit 80 is removed from the frame 10.

[0024] FIG. 4 is an exploded perspective view showing the configuration of the support mechanism 30, FIG. 5 is a perspective view of one engagement member 32 seen from the opposite direction to that of FIG. 4, and FIG. 6 is a perspective view of the other engagement member 33 seen from the opposite direction to that of FIG. 4.

[0025] The support mechanism 30 supports the platen roller 81 at a predetermined position when the platen unit 80 is attached to the frame 10. The predetermined position at which the platen roller 81 is supported is a position where the platen roller 81 faces the thermal head 20 and is in pressure contact with the thermal head 20, as shown in FIG.

[0026] When the platen roller 81 is in a predetermined position, the thermal head 20 prints on the heat-sensitive paper 200 sandwiched between the thermal head 20 and the platen roller 81, and the printed paper 200 is transported by the rotation of the platen roller 81.

[0027] The support mechanism 30 includes a shaft member 31 , engagement members 32 and 33 , and a guide plate 39 .

[0028] One end (tip) 31c of the shaft member 31 is rotatably supported by the side plate 11, and the other end (terminal) 31d of the shaft member 31 is rotatably supported by the side plate 12. As a result, the shaft member 31 is disposed so that the axis C2 is parallel to the width direction W, that is, parallel to the axis C1 of the platen roller 81 when attached to the frame 10.

[0029] An end portion 31a on the inner side of the tip end 31c of the shaft member 31 and an end portion 31b on the inner side of the end portion 31d of the shaft member 31 are each formed flat at two points on the outer circumferential surface, and the cross section is formed into a generally rectangular outline.

[0030] As shown in FIG. 4, the engaging member 32 is fitted into one end 31a of the shaft member 31, and the engaging member 33 is fitted into the other end 31b of the shaft member 31, and both engaging members 32, 33 rotate integrally with the shaft member 31 around the axis C2.

[0031] In addition, if the shaft member 31 connects the two engaging members 32, 33, a rotating shaft may be provided on both engaging members 32, 33, etc., in addition to the shaft member 31. In this case, the shaft member 31 may be located at a position shifted from the rotation center of the rotating shaft.

[0032] Furthermore, even though the shaft member 31 is a rotating shaft, it is not limited to a cylindrical shape. For example, the tip 31c and the end 31d can be formed in a flat plate shape, and the shaft hole into which these are inserted can be formed in a circular shape, thereby allowing the shaft member 31 to rotate.

[0033] 4 and 5, the engagement member 32 has a plate portion 32b and a protrusion 32a. The plate portion 32b has a surface 32g facing toward the center of the width direction W of the shaft member 31 and formed perpendicular to the axis C2 direction. The protrusion 32a is formed to protrude from the surface 32g toward the center of the width direction W of the shaft member 31.

[0034] 2, the surface 32g is formed as a guide surface that regulates the position of one side edge 210 in the width direction W of the paper 200 transported between the thermal head 20 and the platen roller 81. On the other hand, the outer peripheral surface 32c of the protrusion 32a is formed as a surface that guides the surface of the paper 200, similar to a surface 39c of a guide plate 39 described later.

[0035] A fitting hole 32d is formed in the protruding portion 32a and the plate portion 32b so as to penetrate in a straight line. The fitting hole 32d is formed in a roughly rectangular shape, and the end portion 31a of the shaft member 31 is fitted into the fitting hole 32d.

[0036] An engagement claw 32e formed in a hook shape is formed on the upper part of the plate portion 32b, and a pressing portion 32f is formed on the plate portion 32b in the vicinity of the engagement claw 32e.

[0037] 4 and 6, the engagement member 33 has a plate portion 33b, a protrusion 33a, and a finger hook portion 34. The plate portion 33b and the protrusion 33a are formed symmetrically with the plate portion 32b and the protrusion 32a in the width direction W. That is, the plate portion 33b has a surface 33g facing toward the center of the width direction W of the shaft member 31, which is formed perpendicular to the axis C2. The protrusion 33a is formed to protrude from the surface 33g toward the center of the width direction W of the shaft member 31.

[0038] 2, the surface 33g is formed as a guide surface that regulates the position of the other side edge 220 in the width direction W of the paper 200 transported between the thermal head 20 and the platen roller 81. On the other hand, the outer peripheral surface 33c of the protrusion 33a is formed as a surface that guides the surface of the paper 200, similar to a surface 39c of a guide plate 39 described later.

[0039] A fitting hole 33d is formed in the protruding portion 33a and the plate portion 33b so as to penetrate in a straight line. The fitting hole 33d is formed in a roughly rectangular shape, and the end portion 31b of the shaft member 31 is fitted into the fitting hole 33d.

[0040] An engagement claw 33e formed in a hook shape is formed on the upper part of the plate portion 33b, and a pressing portion 33f is formed on the plate portion 33b in the vicinity of the engagement claw 33e.

[0041] As shown in FIG. 4, the engaging member 33 is biased by a torsion spring 38 provided on the frame 10 in the direction of an engaging position, which will be described later.

[0042] The finger hook 34 is formed to protrude from the plate portion 33b toward the opposite side in the width direction W from the protrusion 33a, i.e., toward the outside in the width direction W. The finger hook 34 is a portion on which a user of the printer 100 places his / her finger to rotate the engaging member 33 around the axis C2 of the shaft member 31. By placing a finger on the finger hook 34 and rotating the engaging member 33, the engaging member 33, the shaft member 31, and the engaging member 32 can be rotated integrally around the axis C2.

[0043] The finger hook 34 is formed at a position where the distance from the axis C2 is longer than the distance from the axis C2 to the engaging claw 33e.

[0044] Here, the distance along the axis C2 between the surface 32g of the engaging member 32 and the surface 33g of the engaging member 33 is set to be approximately equal to or slightly longer (at most about 1 mm) than the length of the width direction W of the paper 200. Therefore, the position in the width direction W of the paper 200 transported between the thermal head 20 and the platen roller 81 is regulated by the surfaces 32g and 33g, thereby preventing or suppressing the paper 200 from skewing.

[0045] 7 is a front view of the printer 100 as seen from the front side of FIG. 1, and FIG. 8 is a cross-sectional view taken along line AA in FIG. 7, showing the state in which the engaging claw 33e (32e) of the engaging member 33 (32) is engaged with the engaged portion 82b formed on the holder 82 of the platen unit 80 to support the platen roller 81 in a predetermined position.

[0046] Fig. 9 is a cross-sectional view taken along line BB in Fig. 7, and Fig. 10 is a cross-sectional view taken along line CC in Fig. 7. Note that the cross-sectional view taken along line DD in Fig. 7 is essentially the same as Fig. 8, which is a cross-sectional view taken along line AA, and therefore is omitted here.

[0047] Also, Figure 11 is a cross-sectional view corresponding to Figure 8, showing a state in which the engaging member 33 (32) has rotated counterclockwise around the axis C2, the engaging claw 33e (32e) has disengaged from the engaged portion 82b, and the engaging member 33 (32) is in a released position where it is disengaged from the platen unit 80.

[0048] 12 is a cross-sectional view corresponding to FIG. 8, showing a state in which the engaging member 33 (32) has further rotated counterclockwise about the axis C2 from the state shown in FIG. 11, and the pressing portion 33f (32f) of the engaging member 33 (32) has pushed upward the holder 82, which has been released from the engagement with the engaging member 33 (32), thereby moving the platen roller 81 from a predetermined position.

[0049] FIG. 13 is a cross-sectional view equivalent to FIG. 8, showing a state in which the platen unit 80 has been moved upward and removed from the side plate 12 (11) from the state shown in FIG.

[0050] When the shaft portions 81a, 81b of the platen unit 80 are attached to the notches 11a, 12a of the side plates 11, 12 of the frame 10, the engagement claws 32e, 33e are inserted into the recess 82a formed in the lower part of the holder 82, but in this state, the engagement claws 32e, 33e are not engaged with the engaged portions 82b, 82b of the holder 82.

[0051] When the platen unit 80 is further pressed downward along the notches 11a, 12a, the platen unit 80 moves downward and the engaging claws 32e, 33e engage with the engaged portions 82b, 82b as shown in Fig. 8. The position where the engaging claws 32e, 33e engage with the engaged portions 82b, 82b is the engaging position of the engaging members 32, 33. As shown in Fig. 8, the engaging members 32, 33 can be moved to a release position where they are released from engagement with the engaged portions 82b, 82b by rotating the shaft member 31 around the axis C2 in the direction of the arrow.

[0052] When the engagement claws 32e and 33e are in the engagement position, the engaged platen roller 81 is supported at a predetermined position. This predetermined position of the platen roller is a position facing the thermal head 20 and pressed against the thermal head 20. At this predetermined position, the platen roller 81 is pressed by the thermal head 20 with the elastic force of the torsion spring, and as shown in FIG. 10, printing can be performed on the paper 200 fed between the platen roller 81 and the thermal head 20.

[0053] The guide plate 39 is disposed between the engagement members 32 and 33. As shown in Fig. 2, the guide plate 39 is a guide plate that supports the paper 200, which is a medium on which printing is performed by the printer 100, in the thickness direction of the paper 200 and guides the paper 200. In other words, a surface 39c of the guide plate 39 guides the surface of the paper 200. The shaft member 31 is passed through the guide plate 39, and a claw (not shown) of the guide plate 39 is hooked and fixed to the connecting member 13 (see Fig. 4). Therefore, the guide plate 39 does not rotate even if the shaft member 31 rotates.

[0054] As shown in Fig. 4, notches 39a and 39b are formed at both ends in the width direction W of the front side of the guide plate 39. In one notch 39a, as shown in Fig. 2, the protrusion 32a of the engaging member 32 is disposed, and in the other notch 39b, as shown in Fig. 3, the protrusion 33a of the engaging member 33 is disposed.

[0055] At this time, the outer peripheral surface 32c of the protrusion 32a and the outer peripheral surface 33c of the protrusion 33a are formed so as to be substantially flush with the surface 39c of the guide plate 39. Therefore, the outer peripheral surface 32c of the protrusion 32a and the outer peripheral surface 33c of the protrusion 33a serve as guide surfaces that guide the surface of the paper 200.

[0056] Furthermore, both end edges 39d, 39e of the guide plate 39 in the width direction W where the notches 39a, 39b are not formed are positioned with a small gap between them and the surfaces 32g, 33g of the engaging member 32 (33), which are guide surfaces that regulate the side edges 210, 220 (see FIG. 2) of the paper 200, as shown in FIG. 4 and FIG. 14.

[0057] <effect> In the printer 100 of the embodiment configured as described above, when the engaging member 33 (32) is biased to the engaging position by the torsion spring 38, as shown in FIG. 8, the engaging claw 33e (32e) engages with the engaged portion 82b of the recess 82a of the platen unit 80, thereby supporting the platen roller 81 in a predetermined position, i.e., in a pressed state facing the thermal head 20.

[0058] The platen roller 81, which is in a predetermined position, is pressed by the thermal head 20, which is biased by a torsion spring (not shown), and the platen roller 81 is subjected to a pressing force directed diagonally upward. However, because the notches 11a, 12a of the side plates 11, 12 into which the shaft portions 81a, 81b of the platen roller are fitted are open only upward, the platen roller 81 tries to move upward along the notches 11a, 12a.

[0059] However, since the engaging claw 33e (32e) biased to the engaging position is engaged with the engaged portion 82b, the platen unit 80 does not move upward and remains supported in a predetermined position, and in this state, printing and transport of the paper 200 is performed, as shown in FIG. 10.

[0060] When a user places his / her finger on finger hook portion 34 of engaging member 33 and rotates engaging member 33 counterclockwise against the elastic force of torsion spring 38, engaging claw 33e rotates within recess 82a and moves to a release position where it is disengaged from engaged portion 82b, as shown in FIG. 11, and the engagement between engaging claw 33e and engaged portion 82b is released.

[0061] Since the engaging member 33, the shaft member 31, and the engaging member 32 are integrated, the rotation of the engaging member 33 is transmitted to the engaging member 32 via the shaft member 31, causing the engaging claw 32e of the engaging member 32 to also rotate, and the engaging claw 32e moves to a release position where it is disengaged from the engaged portion 82b, and the engagement between the engaging claw 32e and the engaged portion 82b is also released.

[0062] As a result, the support mechanism 30 is disengaged from the platen unit 80. Since the disengaged platen roller 81 is subjected to a pressing force from the thermal head 20 as described above, the platen unit 80 can move upward as described above.

[0063] However, due to the forward component of the pressing force, shaft portion 81a of platen roller 81 is pressed against the side edge of notch 11a in side plate 11, and shaft portion 81b is pressed against the side edge of notch 12a in side plate 12, which generates frictional forces between shaft portion 81a and side plate 11 and between shaft portion 81b and side plate 12, and this may cause the platen unit 80 to remain attached to frame 10 without moving upward.

[0064] Here, in the printer 100, a pressing portion 32f is formed on the engaging member 32, and a pressing portion 33f is formed on the engaging member 33. Then, in the released state in which the engaging claw 33e (32e) shown in FIG. 11 is disengaged from the engaged portion 82b, the engaging member 33 (32) further rotates counterclockwise, causing the pressing portion 33f (32f) to press upward against the lower surface 82c of the holder 82 of the platen unit 80.

[0065] As a result, as shown in FIG. 12, against the frictional force between the shafts 81a, 81b and the side plates 11, 12, the platen unit 80 is physically pushed upward, and the platen roller 81 is released from the state in which it is pressed against the thermal head 20, and can be easily removed from the frame 10.

[0066] In the state in which the platen unit 80 can be easily removed from the frame 10, the platen roller 81 has moved from a predetermined position, but the shafts 81a, 81b remain positioned in the notches 11a, 12a of the side plates 11, 12, so that the platen unit 80 is attached to the frame 10. When the user pulls up the platen unit 80 from this state, the platen unit 80 becomes detached from the frame 10, as shown in FIG.

[0067] In the present embodiment, the support mechanism 30 that supports the platen unit 80 has surfaces 32g, 33g of the engagement members 32, 33 that function as guide surfaces that regulate the position of the side edges 210, 220 of the paper 200 in the width direction W. Therefore, the printer 100 does not need to provide a paper regulating member that is separate from the support mechanism 30 and that regulates the position of the paper 200 in the width direction W.

[0068] As a result, in the support mechanism 30 and printer 100 of this embodiment, the space required for arranging the engagement members and the paper regulating members side by side in the width direction W of the printer 100 can be reduced to the space required for arranging the engagement members 32, 33, thereby reducing the size of the printer 100 in the width direction W.

[0069] Furthermore, since the support mechanism 30 and printer 100 do not require the thickness of the engagement members or paper regulating members arranged side by side to be reduced, it is possible to reduce the size in the width direction W while preventing or suppressing a decrease in the strength of the support mechanism 30 and the paper regulating members that would occur by reducing their thickness.

[0070] In addition, in the support mechanism 30 and printer 100 of this embodiment, when the engagement claws 32e, 33e are engaged with the engaged portions 82b, 82b of the holder 82 of the platen unit 80, respectively, the load (engagement force) generated by the engagement between the engagement claws 32e, 33e and the engaged portions 82b, 82b acts on the support mechanism 30 as an engagement torque around the axis C2.

[0071] Here, since the distance from axis C2 to finger hook portion 34 is longer than the distance from axis C2 to the portion where torsion spring 38 is hooked, even if the load applied to finger hook portion 34 is smaller than the elastic force of torsion spring 38, the engagement between engaging claw 33e and engaged portion 82b can be released, and the operating force required to release the engagement can be reduced.

[0072] In the support mechanism 30 of this embodiment, the plate portions 32b, 33b and the convex portions 32a, 33a of the engaging members 32, 33 are formed integrally, so that the surface 32g that abuts against the side edge 210 of the paper 200 to regulate the position of the paper 200 in the width direction W is connected without any gaps to the outer peripheral surface 32c of the convex portion 32a that regulates the position of the paper 200 in the thickness direction, and the surface 33g that abuts against the side edge 220 of the paper 200 to regulate the position of the paper 200 in the width direction W is connected without any gaps to the outer peripheral surface 33c of the convex portion 33a that regulates the position of the paper 200 in the thickness direction.

[0073] In other words, in a case where the surface that regulates the position of paper 200 in the width direction W and the surface that regulates the position of paper 200 in the thickness direction are formed separately, a small gap is formed between the surface that regulates the position of paper 200 in the width direction W and the surface that regulates the position of paper 200 in the thickness direction. If such a gap exists, a slight skewing can cause the side edge portion including side edge 210 or the side edge portion including side edge 220 of paper 200 to enter the gap, causing paper 200 to jam or fold irregularly, resulting in a malfunction in which paper 200 is not transported properly.

[0074] However, in the support mechanism 30 of this embodiment, the surfaces 32g, 33g that regulate the position of the paper 200 in the width direction W and the outer peripheral surfaces 32c, 33c that regulate the position of the paper 200 in the thickness direction are integrated, so that the above-mentioned gap is not formed, and even if the paper 200 is skewed, there is no gap through which the paper 200 can enter. Therefore, it is possible to prevent or suppress the paper 200 from entering a gap and becoming jammed, etc.

[0075] That is, for example, when the paper 200 is loaded into the printer 100, the leading edge of the paper 200 in the feed direction is sandwiched between the thermal head 20 and the platen roller 81, as shown in Fig. 10. Then, the paper 200 moves from the sandwiched position in the direction opposite to the conveyance direction of the paper 200, that is, onto the surface 39c of the guide plate 39.

[0076] Therefore, the gap formed between the outer peripheral surface 32c of the protrusion 32a and the surface 39c of the guide plate 39 is covered by the paper 200 placed on the surface 39c of the guide plate 39. This prevents the end of the paper 200 in the feed direction from entering the gap formed between the outer peripheral surface 32c and the surface 39c.

[0077] 14 is a partial perspective view showing a stopper portion 32h formed on the engagement member 32. Furthermore, when the paper 200 is skewed, the upstream portion (in the feeding direction) where the lower surface of the paper 200 begins to be guided by the surface 39c of the guide plate 39, which is opposite the downstream portion (in the feeding direction) of the paper 200 that is sandwiched between the thermal head 20 and the platen roller 81, becomes displaced in the width direction W by a large amount due to the skew in the downstream portion. In other words, the amount of displacement of the paper 200 in the width direction W becomes larger the further upstream it is.

[0078] For example, the paper 200 that has been shifted toward one of the engagement members 32 due to the shift in the width direction W caused by the skew is significantly shifted toward the engagement member 32 at the upstream portion 32j where it begins to be guided by the surface 39c of the guide plate 39 shown in Fig. 14, and the side edge 210 of the paper 200 on the shifted side comes into strong contact with the vertical surface 32g of the plate portion 32b. As a result, the side edge portion of the paper 200, including the side edge 210, that comes into strong contact with the surface 32g, is bent downward.

[0079] Furthermore, unlike this embodiment, if plate portion 32b and convex portion 32a were formed separately in this upstream portion 32j, the side edge portion of the paper 200 bent downward as described above could enter the small gap formed between surface 32g of plate portion 32b and outer peripheral surface 32dc of convex portion 32a, causing the paper 200 to become jammed.

[0080] In contrast, in the printer 100 of this embodiment, the plate portion 32b and the convex portion 32a are formed integrally, and therefore the surface 32g of the plate portion 32b and the outer peripheral surface 32c of the convex portion 32a are connected without any gaps. As a result, the side edge of the slanted paper 200 does not enter between the plate portion 32b and the convex portion 32a, and therefore the paper 200 does not get jammed between the plate portion 32b and the convex portion 32a.

[0081] The same is true when the paper 200 is skewed to the opposite side; in the printer 100, since the surface 33g of the plate portion 33b and the outer peripheral surface 33c of the convex portion 33a are connected without any gaps, the side edge portion on the side edge 220 side of the skewed paper 200 does not enter between the plate portion 33b and the convex portion 33a, and therefore the paper 200 does not get jammed between the plate portion 33b and the convex portion 33a.

[0082] In this embodiment, the protrusion 32a of the engagement member 32 is formed on the upstream portion 32j (in the feed direction) of the plate portion 32b, and is not formed on the portion 32k downstream of the upstream portion 32j. Therefore, in the downstream portion 32k, a gap may be formed between the surface 32g of the plate portion 32b and the edge 39d of the guide plate 39 shown in FIG.

[0083] However, as described above, the amount of deviation in the width direction W of the skewed paper 200 increases the further upstream it goes, so that the upstream portion 32j strongly contacts the surface 32g of the plate portion 32b.

[0084] However, in downstream portion 32k, which is located downstream of upstream portion 32j, the amount of deviation in width direction W of paper 200 is smaller than in upstream portion 32j, and the strength with which side edge 210 of paper 200 contacts surface 32g is smaller. As a result, as described above, even if a gap is formed between surface 32g of plate portion 32b and edge 39d of guide plate 39 in downstream portion 32k, the side edge portion of paper 200 on the side edge 210 side does not easily enter this gap.

[0085] The same is true when the paper 200 is skewed to the opposite side; in the printer 100, the convex portion 33a of the engaging member 33 is formed on the upstream portion 33j (in the feed direction) of the plate portion 33b, and even if a gap is formed between the surface 33g of the plate portion 33b and the edge 39e of the guide plate 39 at the downstream portion 33k, the side edge portion on the side edge 220 side of the paper 200 does not easily enter this gap.

[0086] Therefore, in the printer 100 of this embodiment, the side edge of the paper 200 in the width direction W does not enter between the plate portion 32b and the protruding portion 32a, between the plate portion 33b and the protruding portion 33a, or between the plate portions 32b, 33b and the guide plate 39 due to the paper 200 being skewed, and it is possible to prevent or suppress the occurrence of jamming of the paper 200. Note that both end edges 39d, 39e of the guide plate 39 may be formed so as to be disposed with no gap between them and the faces 32g, 33g.

[0087] As shown in Fig. 14, the support mechanism 30 of this embodiment includes a stopper portion 32h formed by extending the thickness (dimension along the width direction W) of the engagement member 32 outward in the width direction W beyond the plate portion 32b. In other words, the thickness d1 of the plate portion 32b including the stopper portion 32h is formed thicker than the thickness d2 of the plate portion 32b excluding the stopper portion 32h (d2 <d1)。

[0088] The stopper portion 32h is formed so as to be located close to the end surface 11b of the side plate 11 at the engagement position within the movement range (rotation range) of the engagement member 32 between the engagement position and the release position.

[0089] Although not shown in the drawings, the engaging member 33 also has a stopper portion that is the same as the stopper portion 32h of the engaging member 32. The stopper portion of the engaging member 33 is formed so as to be located close to the end face of the side plate 12 when the engaging member 33 is at the engaging position within the movement range (rotation range) between the engaged position and the released position.

[0090] When the platen unit 80 is attached to the frame 10 and in a specified position (when the engaging members 32, 33 are in the engaged position), the engaging claws 32e, 33e abut against the engaged portion 82b, and the engaging members 32, 33 do not rotate beyond the engaged position (in the opposite direction from the engaged position to the released position), and therefore the stopper portion 32h does not come into contact with the frame 10.

[0091] On the other hand, in a state where the platen unit 80 is detached from the frame 10, the engaging members 32, 33 rotate beyond the engaging position due to the elastic force of the torsion spring 38. In this case, the stopper portion 32h abuts against the frame 10, and each of the engaging members 32, 33 is maintained in a stopped state at a position where it has rotated slightly beyond the engaging position.

[0092] As a result, when the removed platen unit 80 is attached to the frame 10, the engagement claws 32e, 33e are stopped near the engagement position, so that the engagement claws 32e, 33e can be stored in the recesses 82a of the platen unit 80, and the engagement claws 32e, 33e can be prevented from interfering with the holder 82.

[0093] In the support mechanism 30 and printer 100 of this embodiment, the engagement members 32, 33 of the support mechanism 30 engage with the holder 82 of the platen unit 80 to indirectly support the platen roller 81 in a predetermined position, but the support mechanism and printer for the platen roller according to the present invention may support the platen roller in a predetermined position by directly engaging the engagement members with the shaft of the platen roller, etc. In this case, a holder for holding the platen roller may or may not be provided.

[0094] The printer 100 of this embodiment is a printer to be built into a device, but the printer according to the present invention is not limited to a printer to be built into a device, and may be an independent printer having a paper storage section for storing paper and an outer case. [Explanation of symbols]

[0095] 10 Frames 30 Support mechanism 31 Shaft member 32, 32 Engagement member 32g,33g side 80 Platen unit 81 Platen roller 100 Built-in printer (printer) 200 Paper C1,C2 axis W Width direction

Claims

1. A platen roller support mechanism that supports a platen roller by pressing the platen roller against a print head at a predetermined position when a platen unit including a platen roller or a holder that holds the platen roller and that is detachable from a base member is attached to the base member, the platen roller comprising: a shaft member disposed parallel to the platen roller, and engagement members provided at both ends of the shaft member, the engaging member engages with the platen roller or the platen unit when the platen roller or the platen unit is attached to the base member, and is rotatable between an engaging position where the engaging member supports the platen roller at the predetermined position and a releasing position where the engaging member is released from the platen roller or the platen unit, and a surface of the engaging member that intersects with the longitudinal direction of the shaft member is formed as a guide surface that regulates the widthwise position of paper transported between the print head and the platen roller, a guide plate for supporting the paper in a thickness direction between the two engaging members; the engaging member has a protrusion protruding from the guide surface toward a center of the shaft member in a longitudinal direction, The guide plate is formed with a notch in which the protrusion is disposed, A support mechanism for a platen roller, wherein an outer peripheral surface of the convex portion is formed as a surface that guides the paper in a thickness direction.

2. The engaging member has a stopper portion formed to extend outward in a longitudinal direction of the shaft member, 2. The support mechanism for a platen roller according to claim 1, wherein the stopper portion abuts against a part of the base member so as to prevent the engagement member from rotating from the engagement position in a direction opposite to a direction toward the release position when the platen roller or the platen unit is detached from the base member.

3. A platen roller support mechanism that supports a platen roller by pressing the platen roller against a print head at a predetermined position when a platen unit including a platen roller or a holder that holds the platen roller and that is detachable from a base member is attached to the base member, the platen roller comprising: a shaft member disposed parallel to the platen roller, and engagement members provided at both ends of the shaft member, the engaging member engages with the platen roller or the platen unit when the platen roller or the platen unit is attached to the base member, and is rotatable between an engaging position where the engaging member supports the platen roller at the predetermined position and a releasing position where the engaging member is released from the platen roller or the platen unit, and a surface of the engaging member that intersects with the longitudinal direction of the shaft member is formed as a guide surface that regulates the position in the width direction of paper transported between the print head and the platen roller, The engaging member has a stopper portion formed to extend outward in a longitudinal direction of the shaft member, a support mechanism for a platen roller, the stopper portion abutting against a part of the base member so as to prevent the engaging member from rotating from the engaged position in a direction opposite to the direction of the released position when the platen roller or the platen unit is detached from the base member.

4. 4. The support mechanism for a platen roller according to claim 1, wherein the engagement member has a pressing portion that presses the platen roller or the platen unit in a direction to remove the platen roller or the platen unit from the base member within a range of movement from the engagement position to the release position.

5. a print head supported on a base member; a platen unit including a platen roller or a holder that holds the platen roller, the platen unit being detachable from the base member; A printer comprising: a support mechanism for a platen roller according to claim 1 , the support mechanism supporting the platen roller at a predetermined position.

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