JP2003305910A - Printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer in which torque control of a drive motor for rotating a take-up core can be simplified. <P>SOLUTION: The thermal printer A comprising a feed core 2 wounded with a recording ribbon 1, and a take-up core 3 for winding the recording ribbon 1 from the feed core 2 and performing printing by feeding the recording ribbon 1 to a recording section is further provided with a drive motor 12 generating the rotating force of the take-up core and the feed core, a first torque limiter 17 for limiting the rotating force being applied to the take-up core 3, and a second torque limiter 18 for limiting the rotating force being applied to the feed core 2 wherein the rotating force being limited by the first torque limiter 17 is set lower than the rotating force being limited by the second torque limiter 18. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer,
For example, the present invention relates to a recording ribbon feeding technique suitably applied to a thermal printer including a thermal head and a platen roller arranged so as to face the thermal head.

[0002]

2. Description of the Related Art In a thermal printer having a thermal head and a platen roller arranged to face the thermal head, a recording medium to be printed and a recording ribbon are interposed in a recording portion between the thermal head and the platen roller. Then, a thermal printer configured to perform printing by thermal transfer or thermal sublimation has been put into practical use.

Particularly, in a thermal printer for performing color printing, when a recording medium is conveyed in forward and backward directions by a conveying roller,
It is configured to control the rotation of the supply core and the take-up core around which the recording ribbon is wound, and to perform color printing by recording for each YMC color laid on the recording ribbon in a frame-sequential manner. In this thermal printer, it is necessary to set the winding force of the recording ribbon to be equal to or less than the pulling force determined by the recording pressure in the recording unit. If the winding force of the recording ribbon is not set to be less than the pulling force determined by the recording pressure and the winding core is wound so as to pull the recording ribbon with a strong winding force, a defective printing of streaking called banding may occur. Therefore, in order to prevent this printing defect, torque control of the drive motor for rotating the winding core is performed.

Typically, the chopper energization control of the drive motor for rotating the winding core is performed so that the recording portion is not affected by the winding force of the recording ribbon.

Alternatively, as in the proposal disclosed in Japanese Patent Laid-Open No. 2001-322303, a ribbon roller that rotates in association with winding and rewinding of a recording ribbon is provided, and the number of rotations of the ribbon roller is detected, The feeding of the recording ribbon is controlled.

[0006]

However, in order to control the torque of the drive motor for rotating the winding core as described above, the winding diameter of the outer peripheral surface of the winding core changes with the consumption of the recording ribbon. There is a need to. For this reason, there is a problem in that it requires a sensor for detecting the winding diameter and the like, which is considerably large.

Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to provide a printer capable of simplifying torque control of a drive motor for rotating a winding core.

[0008]

[Means for Solving the Problems]
To achieve the object, according to the present invention, a supply core around which a recording ribbon is wound, and a winding core that winds the recording ribbon from the supply core are provided, and the recording ribbon is supplied to a recording unit. And a printer for performing printing, which includes a rotation drive unit that generates a rotation force of the winding core and the supply core, and a first rotation force limiting unit that limits the rotation force applied to the winding core by the rotation driving unit. A torque limiter and a second torque limiter for limiting the rotational force applied to the supply core by the rotary drive means are provided, and the rotational force limited by the first torque limiter is the second torque limiter. It is characterized in that it is smaller than the rotational force limited by the torque limiter.

Further, the rotation driving means rotates the winding core so that the recording ribbon is wound by the winding core at a transport speed of a recording medium sent to the recording portion or more. It has a feature.

The rotation driving means is capable of rotating the supply core in the forward and reverse directions. Further, when the supply core rotates in the reverse direction, the rotational force from the rotation driving means applies to the winding core. It is characterized by a clutch to prevent it from being urged.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention, which is a configuration applied to a thermal printer, will be described below with reference to the accompanying drawings. Here, the present invention is
It is needless to say that the present invention is not limited to the thermal printer described below, and can be applied to all printers that require stable recording by setting the winding force of the recording ribbon to be equal to or less than the recording pressure in the recording unit.

First, FIG. 1A is a plan view which also serves as a block diagram of a thermal printer A according to a first embodiment of the present invention. Further, FIG. 2A is a cross-sectional view taken along the line XX of FIG. 1A.

In FIG. 1A, the thermal printer A
Is a pair of bases 20 arranged to face each other,
20 is the mounting base of each component. In the space between the bases 20, 20, the transport roller 7 and the platen roller 4 are rotatably provided using bearings (not shown). A pulley 8 is fixed to one end of a shaft portion that makes the platen roller 4 rotatable, and a belt is provided between the pulley 8 and a pulley fixed to an output shaft of a first motor 9 fixed to one base portion 20. It is stretched, and is driven to rotate by obtaining driving force from this belt.

Similarly, a pulley (not shown) is also fixed to the shaft body which allows the transport roller 7 to rotate freely, and is stretched between the pulley fixed to the output shaft of the first motor 9. The recording sheet 6 is conveyed in the direction of the arrow at the nip portion between the conveying rollers 7 by being driven by a driving force via a belt (not shown).

Next, referring further to FIG. 2A which is a sectional view taken along the line X--X of FIG. 1A, the printing position is set on the platen roller 4 by a moving mechanism (not shown). A thermal head 5 is provided so as to be movable between the illustrated retracted position. The recording ribbon 1 is stretched between the thermal head 5 and the platen roller 4 as shown in the drawing.

The recording sheet 6 conveyed by the conveying rollers 7 is conveyed below the recording ribbon 1 stretched as described above.

Referring again to FIG. 1A, the recording ribbon 1
Has a width dimension substantially equal to the width dimension of the recording sheet 6. In addition, the recording ribbon 1 is, for example, 3
It is a long body in which each color layer of Y (yellow), M (magenta), and C (cyan) is formed in order in order to enable color printing of 0 screens. Everything is wound and the winding core 3 is consumed.
It is wound so that it can be wound up to the side. After all the recording ribbons 1 have been wound around the winding core 3, they are replaced with unused recording ribbons 1.

The supply core 2 and the take-up core 3 are set in a locked state with respect to the supply core drive member 10 and the take-up core drive member 11, which are rotatably provided by a bearing (not shown) at one of the bases 20. It With this supply core 2,
The take-up core 3 is rotatably provided in a ribbon cassette (not shown), and a portion where the recording ribbon 1 is bridged between the supply core 2 and the take-up core 3 includes a thermal head 5 and a platen roller 4. By sneaking into the space between them, the ribbon cassette can be used as a replacement unit.
Replacement work is easy. Of course, even without the ribbon cassette, the supply core 2 and the winding core 3 can be individually set in the locked state with respect to the supply core driving member 10 and the winding core driving member 11, so that the recording ribbon can be replaced. , Such a configuration is also acceptable.

The supply core driving member 10 and the winding core driving member 11 use a second motor 12 fixed to a sub-base 21 fixed to one base 20 as a common drive source.
In addition, the winding core driving member 1 that locks the winding core 3
1 is a first limiting the rotational force of the second motor 12
The power is transmitted via the torque limiter 17. For this power transmission, the belt 1 is provided between a pulley 13 fixed to the output shaft of the second motor 12 and a pulley 15 fixed to the sub-base 21 and rotatable around a shaft body (not shown).
4 is stretched, and a pulley 16 is fixed to the pulley 15. The pulley 16 includes a flange portion 16
a is formed.

As shown in the sectional view of the main part of the first tokul limiter 17 in FIG. 1B, the flange portion 16a of the pulley 16 is provided between the flange portion 11a of the winding core driving member 11 and the flange portion 16a. The ring 25, the felt 26, and the compression coil spring 24 are provided in a compressed state.

With the above-described structure, the rotational force of the pulley 16 is transmitted to the winding core drive member 11 by the frictional force generated by the felt 26 of the first tokul limiter 17 sliding in the compressed state between the flanges. Is configured.

On the other hand, a second torque limiter 18 for limiting the rotational force applied to the supply core drive member 10 is rotatably provided around a shaft body (not shown) fixed to the sub-base 21. 22 and the supply core driving member 10.

The pulley 22 has a larger diameter than the pulley 16 described above, and by tensioning the belt 23 between the pulleys, the supply core driving member 10 drives the winding core by energizing the second motor 12. The member 11 is driven at about half the rotational speed.

The second torque limiter 18 has substantially the same structure as the first tokul limiter 17 described above, and a description thereof will be omitted. However, as a different structure, the compression force of the compression coil spring 24 is the first tokul limiter 17. It is set larger than the compression coil spring. As a result, the torque limited by the first torque limiter 17 is made smaller than the torque limited by the second torque limiter 18.

Needless to say, each torque limiter is not limited to the one having the above-mentioned structure, and various types can be used.

On the other hand, the first motor 9 and the second motor 1
Reference numeral 2 is connected to a motor driver 51 connected to a control device 50 that controls the entire printer, and is driven by energization based on a command from the control device 50. Further, the control device 50 is connected to a mark sensor 26 for detecting the marks provided for each color in the recording ribbon 1 to find the head of the ribbon.

The operation of the thermal printer described above will be described with reference to FIG. 2A and FIG. 2B which is a sectional view taken along the line X--X of FIG. 1A.

First, in FIG. 2A, the thermal head 5 is moved to the retracted position by a moving mechanism (not shown). In this state, the recording sheet 6 is conveyed, and a sensor (not shown) detects the leading edge of the recording sheet 6 to perform cueing as a preparation for printing. In addition, the mark sensor 26 detects the first color layer and performs cueing.

After that, as shown in FIG. 2B, the thermal head 5 is moved onto the platen roller 4, and the first motor 9 drives the platen roller 4 to print the recording sheet 6 at a printing speed V1. And the recording pressure in the recording unit,
The recording operation is performed by the feeding force T1 determined by factors such as the peeling force of the recording ribbon 1 and the energization of the thermal head 5 based on the printing information in synchronization with the conveyance of the recording sheet 6. Done. This printing speed V1
The slack of the recording ribbon 1 is prevented by setting the ribbon winding speed V2 of the winding core 3 or less.

When this recording operation is performed, the recording ribbon 1 is wound by the winding core 3 at the speed V2 with the rotational force T2 limited by the first torque limiter 17. On the other hand, with the rotational force T3 limited by the second torque limiter 18, the recording ribbon 1 is sent out from the supply core at a speed V3. At this time, due to the difference in the transmission torque between the first torque limiter 17 and the second torque limiter 18, the relationship of rotational force T2 <rotational force T3 is established, and the relationship of the gear ratios of the pulleys 16 and 22 for transmitting power is further provided. Therefore, speed V2> speed V3. Further, the platen roller 4 is rotationally driven so that the relationship of speed V2> printing speed V1 can be maintained. Here, each speed has a relationship of speed V2> printing speed V1> speed V3.

With the above recording operation, the recording ribbon 1
By winding and supplying the recording ribbon 1, the supply side of the recording ribbon 1 can be prevented from loosening during the printing operation, the torque T2 of the winding core 3 is smaller than the torque T3 of the supply core 2, and the thermal head 5 Since it can be made smaller than the feeding force T1 between the platen roller 4 and the platen roller 4, it is possible to prevent the occurrence of banding without affecting the printing operation.

After the printing of the first color is completed by the above recording operation, the recording sheet 6 is conveyed in the reverse direction to repeat the above-described recording operation to form the second color, and further the color printing is performed. After forming three prints required for printing, the recording is completed by discharging the print on the left side of the drawing.

According to the thermal printer configured as described above, an inexpensive DC motor can be used as the second motor 12, and simple on / off control is sufficient, so the cost is inexpensive.

The recording is not limited to the above color printing, and needless to say, for example, it may be for monotone printing. In this case, since the black layer can be printed using the recording ribbon 1, higher speed can be realized. Become.

Next, FIG. 3 (a) is a table of each design condition showing design examples of the supply ribbon and the take-up ribbon.
(b) is a chart showing the relationship between the torques T2 and T3 and the winding length of the recording ribbon 1 per one rotation of each core.

As shown in FIG. 3A, a recording ribbon having a thickness of 0.009 mm is wound around each core having a diameter of 8 mm to a maximum diameter of 16.44 mm, and printing for 36 screens is performed. In such a case, the torque T2 and the torque T3 change according to the number of screens consumed as shown in FIG. In addition, the feed amount per rotation of the winding core and the supply core also changes according to the number of screens consumed.
By changing in this way, the delivery amount per one rotation in the winding core and the supply core is finally reversed from the initial stage.

FIG. 4 (a) is a plan view of the main part of the thermal printer according to the second embodiment, and FIG. 4 (b) is a front view.

In FIGS. 4 (a) and 4 (b), the components which have already been described are designated by the same reference numerals, and the description thereof will be omitted. Differences will be described below.

A one-way clutch 30 is provided between the pulley 15 and the first torque limiter 17 for transmitting power in only one direction, which is the winding direction.
The second motor 12 is a stepping motor or a direct current motor that can be driven in the forward and reverse directions, and is configured to be energized and controlled by a motor driver connected to the control device 50.

Further, instead of the above pulley and belt,
By providing the gears 31, 32, and 33 as illustrated, the power transmission to the supply core is performed via the one-way clutch 30.

The operation of the thermal printer described above will be described with reference to the operation explanatory diagrams of FIGS. 5 (a) to 5 (c).

In FIG. 5A, the first color layer is detected by the mark sensor 35, the ribbon is cued, the thermal head 5 is moved onto the platen roller 4, and the first of the platen roller 4 is moved. Driven by the motor 9 of
The recording sheet 6 is conveyed at a printing speed V1, a feeding force T1 determined by factors such as the recording pressure in the recording section and the peeling force of the recording ribbon 1, and the thermal head 5 is energized based on the printing information. The recording operation is performed by being performed in synchronization with the conveyance of No. 6.

Subsequently, in FIG. 5B, the second motor 12 is driven in the reverse direction, so that the one-way clutch 30 does not transmit power to the winding core 3 and the supply core One-way clutch 30 only for 2
Then, power transmission is performed via the gears 31, 32, and 33. As a result, the recording ribbon 1 is wound around the supply core in the arrow direction. In this way, the color layer detected by the mark sensor 35 can be returned to the recording position,
The unused portion of the recording ribbon 1 can be minimized. That is,
When the printing start position is far from the mark detection position of the ribbon, the length of one color is long in the ribbon format, which is a factor of cost increase. However, the color layer detected by the mark sensor 35 is recorded at the recording position. By returning to, it will be compatible with any ribbon format.

Further, as shown in FIG. 5 (c), when a transparent protective layer 1b is laid on the recording ribbon 1 and thermal transfer is performed so as to protect the color printing surface, a thermal head is used. When the heat generating portion 5a of No. 5 passes through the rear end 6a of the recording sheet 6, it becomes a burr. However, the burr can be neatly peeled off from the rear end 6a by winding the recording ribbon 1 on the supply core side in the arrow direction.

As described above, by not pulling the recording ribbon fed by the printing operation by the winding operation on the winding core side, it is possible to increase the back tension without adversely affecting the printing and for each color. Cue drive control for each can be realized without finely controlling the motor speed and torque tension. Moreover, the recording ribbon can be rewound.

[0046]

As described above, according to the present invention,
It is possible to provide a printer that can simplify torque control of a drive motor for rotating a winding core.

[Brief description of drawings]

FIG. 1A is a plan view also serving as a block diagram of a thermal printer A according to a first embodiment of the present invention, and FIG.
FIG. 3 is a cross-sectional view of a main part of the torque limiter of FIG.

2A is a cross-sectional view taken along line XX of FIG. 1A,
FIG. 1B is a sectional view taken along line XX of FIG.

FIG. 3A is a diagram of design conditions showing design examples of a supply ribbon and a take-up ribbon, and FIG. 3B is torque T2, T3.
2 is a table showing the relationship between the above and the winding length of the recording ribbon 1 per one rotation of each core.

FIG. 4A is a plan view of a main part of a thermal printer according to a second embodiment, and FIG. 4B is a front view of the second embodiment.

5A to 5C are operation explanatory views of the thermal printer.

[Explanation of symbols]

A thermal printer 1 recording ribbon 2 supply core 3 winding core 4 Platen roller 5 thermal head 6 recording sheet 7 Conveyor rollers 9 First motor 10 Supply core drive member 11 Winding core drive member 12 Second motor 13 pulley 14 belt 16 pulley 22 pulley 17 First torque limiter 18 Second torque limiter 20 base 30 one-way clutch

Claims (3)

[Claims] 1. A supply core around which a recording ribbon is wound, a winding core around which the recording ribbon is wound from the supply core,
A printer for supplying the recording ribbon to a recording unit for printing, comprising: a rotation driving unit that generates a rotational force of the winding core and the supply core; and a rotation driving unit that attaches the winding core to the winding core. A first torque limiter for limiting the rotational force to be applied, and a second torque limiter for limiting the rotational force to be applied to the supply core by the rotation driving means, and the first torque limiter The limited rotational force is
A printer having a torque smaller than a rotational force limited by the second torque limiter. 2. The rotation driving means rotates the take-up core so that the take-up core takes up the recording ribbon at a conveying speed of a recording medium sent to the recording section or more. The printer according to claim 1, wherein the printer is a printer. 3. The rotation driving means is capable of rotating the supply core forward and backward.
3. The printer according to claim 1, further comprising a clutch that prevents the rotational force from the rotation driving unit from being applied to the winding core when the supply core rotates in the reverse direction.