JPH0630938B2 - Printer ribbon feeder for printer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer, and more particularly to a print ribbon feeding device that feeds a print ribbon to a print portion of a print head.

[Prior Art] When the print ribbon is fed to the print portion of the print head, the print ribbon feeding speed is set to be lower than the print head moving speed to prevent print defects such as print misalignment.

Therefore, for example, in the print ribbon feeding device disclosed in Japanese Patent Laid-Open No. 58-191182, a first gear driven by a pulley that rotates as the carriage moves,
A second gear body that has two types of gears that are engaged with and retained by the first gear in a planetary motion manner and that has two types of gears that have different outer shapes, and two types that have end portions that engage with the ribbon cartridge and that have different outer shapes. A third gear body having a gear, a fourth gear body that meshes with the third gear body, an outer tooth that meshes with the fourth gear body, and an inner tooth that meshes with the gear body. It is composed of a gear body No. 5 and is decelerated so as to reduce the feed amount of the print ribbon so that print misalignment does not occur.

[Problems to be Solved by the Invention] However, in the print ribbon feeding device of the printer described above, the speed reducing means is composed of five kinds of gears and gear bodies, so that the speed reducing means becomes large and these gears and gear bodies are used. Requires a large amount of space for mounting the printer and has a problem that the printer becomes large.

According to the present invention, a high reduction ratio can be obtained, and a driving member, a driven gear, and a clutch means are mounted on a coaxial line with a rotation shaft, and the rotation shaft is rotated at a high reduction ratio to print characters with high quality. (EN) Provided is a printing ribbon feeding device for a printer, which is capable of downsizing the device and avoiding an overload on the speed reduction mechanism.

[Means for Solving the Problems] Therefore, the present invention provides a print ribbon feeding device of a printer for feeding a print ribbon to a print portion of a print head that is reciprocally moved along a print sheet. Rotation shaft (75) and fixed gear (65) arranged coaxially with the rotation shaft
And the fixed gear (6) on the same axis as the fixed gear (65).
5) is provided rotatably relative to the drive member (61) connected to the drive source, and is rotatably instructed to an eccentric position in the drive member (61) and the fixed gear (65). ), A planetary gear (73) that meshes with the fixed gear (65), a driven gear (67) that is provided coaxially with the fixed gear (65) and meshes with the planetary gear (73), the fixed gear (65) and the planetary gear. The gear ratio of (73) is different from the gear ratio of the driven gear (67) and the planetary gear (73), and the rotation shaft and the driven gear (67) are coaxial with the rotation shaft (75). ) And a clutch means (75a) for interrupting operation transmission to the rotary shaft when a load greater than a predetermined value is applied to the rotary shaft.

[Operation] With the above configuration, when the drive member rotates, the planetary gear that meshes with the fixed gear provided coaxially with the drive member rotates. Since the gear ratio between the driven gear and the planet gear is different from the gear ratio between the fixed gear and the planet gear, the driven gear rotates with respect to the fixed gear according to the difference in the gear ratio.

Therefore, by arranging the gears and the clutch means constituting the speed reduction mechanism on the coaxial line, the area occupied by the speed reduction mechanism and the clutch means can be significantly reduced, and a high speed reduction ratio can be easily achieved.

Further, when an overload acts on the rotary shaft due to improper feeding of the print ribbon or the like, the rotary shaft slips on the driven gear and rotates independently of the speed reduction mechanism. As a result, the deceleration mechanism will not be damaged due to overload.

[Embodiment] An embodiment will be described below according to an embodiment in which the present invention is applied to an impact type dot printer.

A platen platen 5 is attached to the inner frame 3 of the printer 1, and a sheet feeding device 7 is attached to the main body frame 3 behind the platen 5. A recording paper feeding unit 11 and a journal paper feeding unit 13 are arranged on a frame 9 of the paper feeding device 7. A first feed roller and a second feed roller (neither of which is shown) are rotatably supported by the frame 9 corresponding to the recording paper feeding unit 11 and the journal paper feeding unit 13 behind the Puerten 5 respectively. ing. A first feeding motor such as a DC motor and a step motor and a second feeding motor (neither shown) are connected to the first feeding roller and the second feeding roller, respectively. The recording paper 15 as a printing paper and the journal paper 17 are respectively fed in accordance with the driving of the second feeding motor. The journal paper feeding unit 13
A take-up reel 19 is rotatably supported on the frame 9 according to the above, and the second feeding motor is connected to the take-up reel 19 via a belt 21 and a spring clutch 23. The printed journal paper 17 is wound by the take-up reel 19 according to the drive of the feed motor.

A paper guide plate 25 is attached to the body frame 3 on the front surface of the platen 5. This paper guide plate 25
A guide piece 25a is formed by cutting and raising to the rear of the platen 5 at a position corresponding to the recording paper 15 and the journal paper 17. Further, the sheet guide plate 25 is formed with cut sheet support pieces 25b cut and raised in front of the platen 5 at appropriate intervals, and the guide pieces 25a are attached to the front surface of the platen 5 and cut sheet paper 27 (first sheet). 3). Further, a cut sheet detector 29 such as a photocoupler is provided on the side surface of the main body frame 3 for the cut sheet paper 2.
It is attached according to the mounting position of 7 and detects that the single-cut sheet 27 is attached to the printer 1.

Two guide shafts 31 and 33 are horizontally mounted on the body frame 3 in parallel with the platen 5.
A carriage 35 is slidably supported on the. A print head 37 is attached to the carriage 35, and the print head 38 selectively drives a corresponding print wire (neither is shown) by a large number of built-in electromagnet devices according to the movement of the carriage 35 to record the data. Characters are dot-matrix printed on the paper 15 and the journal paper 17 or the single-cut paper 27. A spiral shaft 39 is rotatably supported by the main body frame 3, and the spiral shaft 3
9 is an electric motor 41 such as a DC motor or a step motor.
Are connected via the first to fifth gears 43, 45, 47, 49, 51, and the spiral shaft 39 moves in the direction of the solid line arrow shown in FIG.
-It is rotated at a predetermined rotation speed according to the reduction ratio of 45, 47, 49, and 51. The second gear 45 and the third gear 47 having different outer diameters are coaxially and integrally formed.
A cam groove 39a for forward movement is provided on the outer peripheral surface of the spiral shaft 39.
And a cam groove 39 for return movement, which are turned around, and the cam groove 3 for forward movement.
A cam follower 35a provided on the carriage 35 is slidably engaged with the cam groove 9b and the return cam groove 39b. The carriage 35 is reciprocated in parallel with the platen 5 according to the rotation of the spiral shaft 39. Further, the lead angle between the forward cam groove 39a and the backward cam groove 39b is set to, for example, about 1: 3, and the carriage 35 is reciprocated at a speed about three times as fast as the forward speed. A lid (not shown) is supported on the guide shaft 31 so as to be openable and closable,
A cutter (not shown) is attached to the lid at a position corresponding to the recording paper 15. Then, the printed recording paper 15 is cut by the cutter.

A ribbon feeding device 53 is attached to the main body frame 3. A stay 57 is integrally punched and formed on a frame 55 of the ribbon feeding device 53, and a fixed shaft 59 is fixed to the stay 57. A first bevel gear 61, which constitutes a driving member of a reduction mechanism, is rotatably supported on the fixed shaft 59, and the first bevel gear 61 has the second gear 45.
A second bevel gear 63, which is integrally formed coaxially with the third gear 47, meshes with the third gear 47. Then, the first bevel gear 61 is rotated counterclockwise around the fixed shaft 59 according to the drive of the electric motor 41. A fixed gear 65 forming a part of a reduction mechanism is fixed to the fixed shaft 59, and a driven gear 67 is rotatably supported. The fixed gear 65 and the driven gear 67 have the same outer shape,
Tooth difference (z1−z2) according to a predetermined reduction ratio {the fixed gear 65 has a fraction z1, the driven gear 67 has a fraction z2, and z
1> z2}. The reduction ratio is higher than the moving speed of the carriage 35 and the print ribbon 8
3 is set so that the print wire is not caught on the print ribbon 38 during the printing operation of the print head 3. A support wall 69, which is partially cut away, is integrally formed on the outer periphery of the upper surface of the first bevel gear 61, and the first bevel gear 61 corresponding to the cutout portion of the support wall 69.
A support shaft 71 is formed on the upper surface of the. A planetary gear 73, which constitutes a part of a reduction mechanism, is rotatably supported on the support shaft 71, and the planetary gear 73 is fixed to the fixed gear 65.
And the driven gear 67. A rotary shaft 75 is rotatably supported by the fixed shaft 69.
A clutch plate 75a forming a part of the clutch means is integrally formed at the lower end of 5. A mounting plate 77 is loosely fitted to the rotary shaft 75, and the mounting plate 75 is fixed to the upper end of the support wall 69. A clutch spring 79, which constitutes a part of clutch means, is attached to the rotary shaft 75 between a clutch plate 75a and a mounting plate 77, and the clutch spring 79 elastically moves the clutch plate 75a to the driven gear. The upper surface of 67 is pressed. As a result, the rotating shaft 75 is rotated integrally with the driven gear 67 by the frictional force between the clutch plate 75a and the driven gear 67 generated by the elastic force of the clutch spring 79.

A ribbon cassette 81 is detachably attached to the upper surface of the frame 55, and the printing ribbon 8 is folded and accommodated in the ribbon cassette 81. The print ribbon 83 is stretched over the entire print line of the platen 5. Therefore, the recording paper 15 and the journal paper 17 or the single-cut paper 27 are stretched over the entire printing line, and a feeding roller 87 and a support roller 89 (shown by a broken line in FIG. 1) built in the ribbon cassette 81 are used to sandwich the ribbon. Retained. The rotary shaft 75 is engaged with the feed roller 87, and the print ribbon 83 is guided to the print portion of the print head 37 as the rotary shaft 75 rotates.
It is collected in 1. A tension knob 85 is attached to the feed roller 87, and the print ribbon 83 is collected in the ribbon cassette 81 even when the tension knob 85 is rotated.

Next, the operation of this embodiment will be described with reference to FIGS. 3 and 6.

As the electric motor 41 is driven, the spiral shaft 39 moves to the third position.
When rotated in the direction of the solid arrow shown in the figure, the carriage 35
Is the rotational speed of the spiral shaft 39 and the forward cam shaft 39a.
The platen 5 is moved to the left end side at a predetermined speed according to the lead angle of the platen. The print head 37 is the carriage 3
In accordance with the forward movement of No. 5, the corresponding printing wire is selectively driven by the built-in electromagnet device to print characters on the recording paper 15 and the journal paper 17 or the cut paper 27 in a dot matrix.

When the first bevel gear 61 is rotated counterclockwise about the fixed shaft 59 in accordance with the forward movement of the carriage 35, the planet gears 73 rotate around the fixed shaft 59 as a planet, and the rotation speed of the first bevel gear 61 is increased. On the other hand, the driven gear 67 is rotated counterclockwise about the fixed shaft 59 at a predetermined reduction ratio according to the tooth number difference (z1-z2) between the fixed gear 65 and the driven gear 67. At this time, since the clutch plate 75a and the driven gear 67 are in pressure contact with each other due to the elastic force of the clutch spring 79, the driven gear 67 generates a frictional force between the clutch plate 75a and the driven gear 67 caused by the elastic force of the clutch spring 79. Causes the rotating shaft 75 to rotate counterclockwise. As a result, the feed roller 87 engaged with the rotary shaft 75 rotates counterclockwise, and the print ribbon 83 held by the feed roller 87 and the support roller 89 at the sandwiching pressure is fed along the print line of the platen 5. After that, the ribbon cassette 81 is collected.

When the printing operation on the recording paper 15 and the journal paper 17 or the cut sheet 27 is completed according to the forward movement of the carriage 35, the carriage 35 moves at a speed corresponding to the rotation speed of the spiral shaft 39 and the lead angle of the backward movement cam groove 39b. Is revived at. At this time, since the leads of the forward movement cam groove 39a and the backward movement cam groove 39b are set to about 1: 3, the carriage 35 moves about three times as fast as the forward movement speed. Since the rotation speed of 39 is constant, the carriage 35 is moved back in about 1/3 of the forward movement time. Further, when the carriage 35 is moved back, the recording paper 15 is fed in accordance with the driving of the first feeding motor so that the next print line corresponds to the print position. Similarly, the journal paper 17 is fed by the drive of the second feeding motor so that the next print line corresponds to the print position, and the printed journal paper 17 is wound by the take-up reel 19.

Further, when the carriage 35 is returned, the print ribbon 83 is fed along the print line of the platen 5 at a predetermined speed, and then the ribbon cassette 81, as in the above-described operation.
Will be recovered in.

When a load greater than the frictional force between the driven gear 67 and the clutch plate 75a, which is generated by the elastic force of the clutch spring 79, acts on the rotary shaft 75 due to improper feeding of the print ribbon 83, the driven gear 67 that rotates at a predetermined reduction ratio. And clutch plate 75a
And slip and the motion transmission to the rotating shaft 75 is cut off. Further, when the tension knob 85 is rotated in the direction shown by the solid arrow in FIG. 6 by a force equal to or greater than the frictional force when the ribbon cassette 81 is attached, the driven gear 67 and the clutch plate 75a slip, The rotating shaft 75 can be rotated independently of the rotation of the movable gear 67. Therefore, the feed roller 87 can be rotated. As a result, the tension knob 85
It is possible to collect the print ribbon 83 into the ribbon cassette 81 with the rotation of and to stretch the print ribbon 83 along the print line of the platen 5.

As described above, in this embodiment, the first bevel gear 6 of the reduction mechanism is used.
1, the fixed gear 65, the driven gear 67, the clutch plate 75a and the clutch spring 79 which form the clutch means are arranged coaxially with the rotating shaft 75, and the planetary gear 73 rotates about the fixed shaft 59 in accordance with the planetary rotation of the planetary gear 73. 1 bevel gear 61
It is possible to rotate the rotary shaft 75 by the driven gear 67 that rotates at a high reduction ratio with respect to the rotational speed of, and feed the print ribbon 83 in accordance with the printing operation of the print ribbon.
Further, a clutch plate 75a and a clutch spring 79 are arranged coaxially with the rotating shaft 75, and a load greater than the frictional force between the clutch plate 75a and the driven gear 67 generated by the elastic force of the clutch spring 79 is applied to the rotating shaft 75. When applied, the motion transmission of the driven gear 67 to the rotary shaft 75 can be interrupted. Further, this makes it possible to reduce the mounting space for the speed reduction mechanism and the clutch means and to downsize the printer.

EFFECTS OF THE INVENTION As described above, according to the present invention, it is possible to arrange the gears and the clutch means on the coaxial line to achieve miniaturization, obtain a high deceleration, and prevent printing ribbon feeding failure or printer failure. When an overload is applied to the rotary shaft when the print ribbon is attached, the power transmission between the speed reducer and the rotary shaft is cut off, and the speed reducer is not damaged.

[Brief description of drawings]

FIG. 1 is a plan view of an impact type dot printer, FIG. 2 is a side view of a printing mechanism, FIG. 3 is a perspective view showing a state in which a ribbon cassette and a ribbon feeding device are removed, and FIG. 4 is a cross section of the ribbon feeding device. 5 and FIG. 5 are exploded perspective views of the ribbon feeding device, and FIG. 6 is an exploded perspective view of main parts. In the figure, 1 is a printer, 15 is a recording sheet as a printing sheet,
Reference numeral 17 is a journal paper as a printing paper, 37 is a print head, 41 is an electric motor, 53 is a ribbon feeding device, 61 is a first bevel gear as a driving member, 65 is a fixed gear, 6
7 is a driven gear, 73 is a planetary gear, 75 is a rotating shaft, and 75a
Is a clutch plate forming a part of the clutch means, 79 is a latch spring forming a part of the clutch means, and 83 is a print ribbon.

Claims (1)

[Claims] 1. A print ribbon feeding device of a printer for feeding a print ribbon to a printing portion of a print head which reciprocates along a print sheet, wherein a rotary shaft (75) for feeding the print ribbon and its rotation. Fixed gear (65) arranged coaxially with the shaft
And the fixed gear (65) coaxially with the fixed gear (65).
A drive member (61) rotatably provided relative to the drive source and connected to a drive source; and a fixed gear (65) rotatably supported at an eccentric position in the drive member (61). A planetary gear (73) meshing with the driven gear (67) coaxially with the fixed gear (65) and meshing with the planetary gear (73), the fixed gear (65) and the planetary gear (73). ) Is a value different from the gear ratio of the driven gear (67) and the planetary gear (73), and the rotation shaft and the driven gear (67) are coaxial with the rotation shaft (75). And a clutch means (75a) interposed between the rotary shaft and the rotary shaft for interrupting motion transmission to the rotary shaft when a load greater than a predetermined value is applied to the rotary shaft. apparatus.