JP2001038972A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printer which can hold a printing quality of a printing mechanism part by driving a platen roller at both sides. SOLUTION: A platen roller 12 having driven gears 17a and 17b fixed to both ends is set to a supporting frame 52 (52a and 52b) which opens and closes to a body frame 4. Driving gears 25a and 25b are set coaxially with an intermediate gear 24 to both sides of the body frame 4. In a state when the supporting frame 52 is closed, the driven gears 17a and 17b are engaged with the driving gears 25a and 25b respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer such as an electronic cash register, and more particularly to a printer in which a paper path is opened when recording paper is loaded.

[0002]

2. Description of the Related Art Generally, in this type of printer,
A printing mechanism for printing on recording paper pulled out from roll paper is provided. Such a printing mechanism section includes, for example, a thermal head and a platen roller, of which a platen roller is disposed on a support frame side that can be opened and closed with a paper path of a recording sheet therebetween, while a thermal head is a printer. It is located on the body side. The thermal head is disposed to face the platen with the paper path therebetween with the support frame closed, and prints on the recording paper sandwiched between the thermal head and the platen.

[0003] A driven gear is fixed to one end of the platen roller, and engages with a driving gear provided on the printer main body side in a state where the support frame is closed so as to receive a driving force to feed the recording paper. It has become.

The support frame is provided with a hole provided in the support frame in the printer body and is pivotally supported by a shaft to perform opening and closing operations. To perform the opening and closing operation, a hole in the support frame and a shaft in the printer body side are required. , It is necessary to provide a predetermined gap.

[0005]

However, in the conventional printer as described above, the driven gear fixed to the platen roller receives driving force on one side from the driving gear provided on the printer main body. There has been a problem that the axial position moves only on one side, and as a result, the force by which the thermal head presses the platen roller differs between the left and right.

[0006] For this reason, the force of pressing the platen roller by the thermal head is different between left and right, resulting in a decrease in print quality or meandering of the recording paper.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the conventional technique, and the thermal head presses the platen roller equally to the right and left, so that
It is an object of the present invention to provide a printer capable of maintaining the printing quality of a printing mechanism.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a printer body having a paper path for recording paper, which is openable and closable. A supporting member capable of opening a paper path, a platen roller is fixedly attached, and a platen roller shaft rotatably supported by the supporting member, and a recording sheet therebetween while facing the platen roller with the paper path interposed therebetween. In a printer having a thermal head for printing while pressing, the platen roller shaft is connected to a pair of rotating drive gears disposed on both sides of the printer main body when the support member is closed. It is characterized in that driven gears rotated together are provided on both sides of the platen.

With the above configuration, when the opened support member is closed, the pair of drive gears and the pair of driven gears provided at both ends of the platen roller shaft engage, and the platen roller shaft is rotated on both sides. The acting force on the platen shaft when the drive gear rotates the driven gear is applied to both sides of the platen shaft, so that the pressing force of the thermal head is equal to the left and right. Therefore, problems such as uneven print quality and meandering of paper, which differ in print quality between right and left, do not occur.

[0010] In the present invention, at least one of the driven gear and the driving gear meshed with each other has a protruding portion which is deformed by meshing with a surface of the other gear which is brought into pressure contact with a tooth of the other gear. Having it is also effective.

According to the present invention, the backlash between the gears is significantly reduced by the projecting portion which is crushed by meshing, so that the platen roller shaft is reliably driven simultaneously on both sides.

When the support frame is closed, for example, when printing on recording paper, the platen is arranged at a position to be opposed to the thermal head, and the drive gear provided on both sides of the printer body and both ends of the platen roller shaft. The provided driven gear engages.

Therefore, according to the present invention, since the platen roller shaft can be driven on both sides, the position of the thermal head does not largely shift from side to side, and the pressing force of the thermal head becomes equal to the left and right. Therefore, problems such as uneven print quality and meandering of paper, which differ in print quality between right and left, do not occur.

[0014] At least one of the driven gear and the driving gear meshed with each other has a protruding portion which is deformed by meshing with a surface of the other gear which is brought into pressure contact with a tooth of the other gear. It is desirable.

According to the present invention, an increase in load due to a reduction in backlash between gears can be prevented.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram illustrating a schematic configuration of the printer according to the present embodiment. FIG. 2 is a schematic configuration diagram illustrating a schematic configuration of the printer with a support frame opened. FIG. 3 is a perspective view illustrating a schematic configuration of a power transmission unit to a platen according to the present embodiment. 4 and 5 are explanatory diagrams of power transmission to a platen roller.

As shown in FIG. 1, the printer 1 of the present embodiment is provided with a main body frame 4 made of, for example, metal. The main body frame 4 includes a bottom 4a and the bottom 4
and a pair of parallel side portions 4b sandwiching a. A paper guide member 6 for forming a paper path P is provided at a front portion of the main body frame 4.

A roll paper storage unit (not shown) for storing roll paper R is provided in front of the printer 1.

As shown in FIG. 1 or FIG.
Is a printing mechanism section 10 for printing on the recording paper S drawn out along the paper path P from the roll paper in the roll paper storage section, and a cutter mechanism section (cutter blade) for cutting the printed recording paper S. 30.

The printing mechanism 10 includes a thermal head 11 for printing by a thermal method, and a platen roller (platen) 12 for supporting the recording paper S between the thermal head 11 and the thermal head 11.
It is composed of

The thermal head 11 includes a main body frame 4
In addition, it is provided rotatably about the support shaft 13.
The thermal head 11 is configured to be urged toward the platen roller 12 by a head pressing spring 14.

On the other hand, the platen roller 12 is provided on a support frame 52 described later.

The platen roller 12 is arranged to face the thermal head 11 with the paper path P interposed therebetween with the support frame 52 closed.

The main body frame 4 is provided with a drive mechanism 20 for driving the platen roller 12 to rotate. In the drive mechanism section 20, a drive motor 21 is provided at a portion on the rear side of the main body frame 4, and the rotational driving force of the drive motor 21 is transmitted from the motor gear 22 to the intermediate gear 24 via the reduction gear 23. It is configured to:

As shown in FIG. 3, a platen gear 17a is provided at both ends of a platen shaft 16 of the platen roller 12.
The intermediate gear 2 is provided at both ends of the intermediate shaft 3.
The gear portions 25a and 25b provided on the concentric shaft 4 are fixed.

When the platen gears 17a and 17b engage with 25a and 25b, respectively, with the support frame 52 closed, the platen roller 12 is driven to rotate in a predetermined direction.

As shown in FIG. 1 or FIG. 2, the cutter mechanism 30 comprises a cutter unit 31 having a movable blade 32 and a fixed blade 41.

The cutter unit 31 is disposed downstream of the printing mechanism 10 in the paper feeding direction and above the main body frame 4. The cutter unit 31 has a cutter case 33 composed of a cutter frame 34 and a cutter cover 35, and the movable blade 32 is provided inside the cutter case 33. A cutter motor 36 for driving the movable blade 32 is provided inside the cutter case 33.

An opening 37 for the movable blade 32 to enter and exit is formed on one side of the cutter case 33, and the opening 37 is arranged to face the paper path P. Also,
At the lower end of the opening 37, a tip 34 b of the bottom 34 a of the cutter frame 34 is formed so as to slightly protrude from the opening 37.

In the cutter unit 31, the movable blade 32 is configured so that the rotational driving force of the cutter motor 36 is transmitted to gears (not shown). As a result, the movable blade 32 exits from the opening 37 of the cutter case 33 across the paper path P (the position indicated by the solid line in FIG. 2).
And a position (the position indicated by the dotted line in FIG. 2) that fits inside the cutter case 33.

On the other hand, the fixed blade 41 is provided on the support frame 52, and is arranged to face the movable blade 32 of the cutter unit 31 with the paper path P interposed therebetween with the support frame 52 closed. .

As shown in FIG. 2, the platen roller 12 of the printing mechanism 10 and the fixed blade 41 of the cutter mechanism 30 are
The support frame 52 is provided.

Here, the support frame 52 includes a base 52a.
And a pair of parallel arms 52b sandwiching the base 52a.
From the above, it is formed in a substantially U-shaped cross section. The interval between both arm portions 52b of the support frame 52 is set slightly longer than the interval between both side portions 4b of the main body frame 4.

On the other hand, the main body frame 4 is provided with a positioning member 60 having a positioning shaft 61 as a center of rotation of the support frame 52 and a positioning groove (locking portion) 62.

When the support frame 52 is closed, the platen roller 12 and the fixed blade 41 are positioned by the positioning member 60 with respect to the thermal head 11 and the movable blade 32, respectively.

Here, the positioning shaft 61 is fixed to the upper front side of the both sides 4b of the main body frame 4 so as to extend toward the outside of the side 4b. On the other hand, a positioning shaft 61 is provided at the rear end edges of both arms 52b of the support frame 52.
Is provided with a long hole 52f which is pivotally supported.

Further, as shown in FIG.
A bearing member (locking portion) 18 that supports the platen shaft 16 is attached to the distal end side of the two side portions 52b. The platen roller 12 is rotatably supported by the support frame 52 by the bearing member 18. On the other hand, as shown in FIG. 2, the positioning grooves 62 are located on both sides 4b of the main body frame 4 and viewed from the side of the side 4b.
1 and the side portion 4b are formed in the vicinity of the overlapping portion.

On the other hand, as shown in FIG. 2 or FIG. 3, the fixed blade 41
Are supported by the support frame 52 so as to be swingable by being supported by the support protrusion 52g formed so as to protrude from the base 52a on the both arms 52b.

The fixed blade 41 is pushed by a compression coil spring 43 attached to the shaft 42 and the fixed blade 41 in a state where the fixed blade 41 is penetrated by the shaft 42 fixed to the base 52 a of the support frame 52. The peripheral portion of the blade portion 41 a of the fixed blade 41 is held while being pressed against the base 52 a of the support frame 52.

A blade cover 44 for covering the blade portion 41a of the fixed blade 41 in this state is provided on the base 52a of the support frame 52.

When the support frame 52 is closed, the bearing member 18 of the platen roller 12 is arranged in the positioning groove 62 of the main body frame 4 so as to face the thermal head 11. In this state, the platen roller 12 is pressed from the thermal head 11 by the urging force of the head pressing spring 14. Also, both end portions 41c on the blade portion 41a side are
The fixed blade 41 engages with the distal end portion 34b of the bottom portion 34a of the base 4 so that the fixed blade 41 and the base 42
a is disposed at a position substantially parallel to the movable blade 32 and is opposed to a position slidable with the movable blade 32.

In this embodiment having such a configuration, recording is performed by driving the thermal head 11 based on predetermined print information while rotating the platen roller 12 to feed the recording paper S along the paper path P. Print on paper S. Then, the recording paper S is cut by sliding the movable blade 32 crosswise to the fixed blade 41. Then, as shown in FIG. 4, in the printing state, the driving gear 25a (25b) coaxial with the intermediate gear 24 rotates in the direction of arrow B, and the driven gear 17a (17b) fixed to both ends of the platen roller 12 moves to the direction of arrow A. Drive in the direction. At this time, the driven gear 17a (17
b) receives the force to move in the direction of the arrow D together with the driving force, and resists the spring force of the head pressing spring 14 so that the thermal head 11
Is moved in the direction of arrow C. Further, since the force of moving in the direction of arrow D varies depending on the force for feeding the recording paper S, for example, when the load such as when starting to feed the recording paper S is large and when the load for performing normal printing is small, The position of the thermal head 11 fluctuates greatly.

However, in this embodiment, the platen roller 12
Are driven on both sides, so that the position of the thermal head 11 does not largely shift from side to side,
The pressing force of the left and right becomes equal. Therefore, problems such as uneven print quality and meandering of paper, which differ in print quality between right and left, do not occur.

Further, as shown in FIG.
The backlash between the drive gear 25a (25b) and the driven gear 17a (17b) in which the protruding portion 25c that partially protrudes the tooth shape of (25b) from the normal tooth shape can be reduced, and the platen roller 12 can be more reliably formed. Can be driven on both sides.

The protrusion 25 is, for example, 1 m in the tooth width direction.
The width of m is provided for all tooth lengths. Also, drive gear 2
Since 5a (25b) is formed of a resin such as POM,
The protruding portion 25c is crushed by meshing with the driven gear, and functions to extremely reduce backlash.

On the other hand, when the distance between the driven gears 17a (17b) and the drive gears 25a (25b) is short, there is a concern that the rotational load will increase. The tooth width is narrower than a normal tooth width and is easily crushed, thereby preventing an increase in rotational load.

Further, in the above embodiment, the tooth profile of the drive gear 25a (25b) is partially thicker than the normal tooth profile, but the driven gear 17a (17b) may have the same tooth profile, or Even if both have the same tooth shape, there is no difference in effect. .

[0048]

As described above, according to the present invention, since the platen roller 12 can be driven on both sides, it is possible to obtain a printer in which the printing quality does not differ between left and right, and there is no problem such as uneven printing or meandering of paper.

Further, the drive gear 25a (25b) or the driven gear 17a (17b) is formed to have a partially larger tooth profile than the normal tooth profile, thereby using the drive gear 25a (2b).
5b) and the backlash of the driven gear 17a (17b) can be reduced, and the platen roller 12 can be more reliably driven on both sides.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a schematic configuration of a printer according to an embodiment.

FIG. 2 is a schematic configuration diagram illustrating a schematic configuration of a state where a support frame of the printer is opened.

FIG. 3 is a perspective view showing a schematic configuration of power transmission to a platen roller of the present embodiment.

FIG. 4 is an explanatory diagram of power transmission to a platen roller of the printer.

FIG. 5 is an explanatory diagram of power transmission to a platen roller of the printer.

[Explanation of symbols]

 Reference Signs List 10 printing mechanism section 11 thermal head 12 platen roller (platen) 17 driven gear (platen gear) 18 bearing member (locking section) 25 drive gear 30 cutter mechanism section (cutter blade) 52 support frame (supporting member) 60 positioning member 61 Positioning shaft (locking part) 62 Positioning groove (locking part) P Paper path

Claims (2)

[Claims] A support member provided on a printer body having a paper path for recording paper so as to be openable and closable and capable of opening the paper path by approaching or separating from the paper path; A platen roller shaft rotatably supported by a support member, and a printer having a thermal head for printing while pressing the recording paper therebetween while facing the platen roller with the paper path interposed therebetween, wherein the platen roller shaft is And a driven gear, which is engaged with a pair of rotating drive gears disposed on both sides of the printer body when the support member is closed, and is rotated on both sides of the platen. 2. The at least one of the driven gear and the driving gear that are meshed with each other has a protruding portion that is deformed by meshing with a surface of the other gear that is in contact with the teeth of the other gear. The printer according to claim 1, wherein: