JPH0958070A - Thermal transfer printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the incidence of an error in feeding a sheet by a thermal transfer printer which creates a print sheet for display. SOLUTION: The power of a stepping motor 6 is transmitted to a platen roller 9 and a sprocket wheel 11 through a reduction gear mechanism. The platen roller 9 has a gear 10 with a ball clutch, fitted into the shaft of the roller 9, which is engaged with a reduction gear 8. The peripheral speed of the platen roller 9 is set higher than that of the sprocket wheel 11, and the rotating torque is limited to the value of the resistance to the feeding of a transfer sheet 4 and an ink ribbon 21 or less. The transfer sheet 4 and the ink ribbon 21 are fed by rotation of the platen roller 9 and the sprocket wheel 11, and the platen roller 9 is rotated at the same peripheral speed as the sprocket wheel 11. In addition, the perforation of the transfer sheet 4 is not deformed as the rotary load of the sprocket wheel 11 is light, and therefore, the accuracy of feeding the transfer sheet is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer printer device, and more particularly to a thermal transfer printer device for producing a display sheet or the like.

[0002]

2. Description of the Related Art A thermal transfer printer apparatus for producing a display label or the like by thermally transferring characters or figures to an adhesive sheet with release paper or the like is run by pressing an ink ribbon and a transfer sheet with a platen roller and a thermal head. It is configured and uses tape with a width of about several cm,
There is one that supports wider sheets used for applications such as displays.

The platen roller is rotationally driven by a motor, and while the ink ribbon and the transfer sheet are being fed in close contact with each other, characters and the like are thermally transferred onto the sheet by the thermal head. The printed sheet is sent to the outside, and the ink ribbon is wound on a take-up spool in the cartridge by a motor-driven ink ribbon take-up reel shaft.

In this type of thermal transfer printer, slippage occurs between the sheet and the ink ribbon and the platen roller due to the frictional resistance of the thermal head and the back tension of the ink ribbon, the processing accuracy of the platen roller, and the outside of the platen roller due to temperature changes. There is a problem in that the dimensional accuracy of the printed result is not sufficient because an error occurs in the feed amount due to fluctuations in the diameter dimension and the like.

Therefore, in a large-sized thermal transfer printer using a wide sheet, a sprocket wheel for feeding the sheet is provided in addition to the platen roller, and the sprocket wheel is engaged as a transfer sheet along both side edges in the longitudinal direction of the sheet. It is known that a sheet having perforations arranged in parallel is used to improve the dimensional accuracy of a printed result. This thermal transfer printer apparatus feeds a sheet with a platen roller and a sprocket wheel, and controls the feeding amount with a sprocket wheel to reduce an error in the feeding amount due to a slip between the platen roller and the sheet, and to obtain a print result size. The accuracy is improved.

[0006]

A thermal transfer printer apparatus having a sheet feeding mechanism composed of a sprocket wheel and a platen roller is configured to drive the sprocket wheel and the platen roller synchronously. It is not easy to match the peripheral velocities due to the tolerance of working accuracy. If the peripheral speeds of both sides do not match, the sheet and the ink ribbon are loosened between the platen roller and the sprocket wheel, resulting in defective printing. The perforations of the mating sheets are deformed,
A relative displacement between the sprocket wheel and the sheet may occur, causing an error in the print size.

Therefore, there is a technical problem to be solved in order to eliminate the deviation of the feed amount between the sprocket wheel and the platen roller, improve the running stability and running accuracy of the sheet and the ink ribbon, and improve the printing quality. Therefore, the present invention aims to solve the above problems.

[0008]

DISCLOSURE OF THE INVENTION The present invention is proposed in order to achieve the above-mentioned object, and includes a sprocket wheel for sheet feeding, a platen roller, an ink ribbon take-up reel shaft, which is rotationally driven by a motor, and A thermal transfer printer device comprising a thermal head in pressure contact with the platen roller, wherein the sprocket wheel is engaged with perforations arranged in parallel along both longitudinal edges of the transfer sheet, and the transfer sheet and the ink ribbon are While sandwiching the platen roller and the thermal head, the platen roller and the sprocket wheel are interlocked to feed the transfer sheet, and the ink of the ink ribbon is thermally transferred to the transfer sheet. Friction clutch or ball clutch on the shaft A gear is attached via a torque limiter, and the platen roller is driven by a motor via a reduction gear device, and the peripheral speed of the platen roller at no load is set to be higher than the peripheral speed of the sprocket wheel. The present invention proposes a thermal transfer printer device characterized in that the torque limit value of the torque limiter is set to be equal to or less than the feeding load of the transfer sheet and the ink ribbon.

In the above thermal transfer printer, the transfer sheet having perforations on both side edges and the ink ribbon of the ink ribbon cartridge are sent by being pinched by a platen roller and a thermal head driven by a motor, and the ink ribbon is The transfer sheet is taken up by an ink ribbon take-up spool, and the transfer sheet is delivered by a sprocket wheel.

The peripheral speed of the platen roller is set to be higher than the peripheral speed of the sprocket wheel, and the rotation torque is limited by the torque limiter to the resistance equal to or less than the feeding resistance of the transfer sheet and the ink ribbon. Therefore, the transfer sheet and the ink ribbon are sent by the combined rotational torque of the platen roller and the sprocket wheel, and the platen roller rotates at the peripheral speed synchronized with the sprocket wheel.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. For the convenience of description, conventionally known technical matters will be described at the same time. FIG. 1 shows a side surface of a thermal transfer printer device 1, in which an upper cover 3 is pivotally attached to a frame 2 so as to be openable and closable. A roll sheet supporting roller 5 for supporting the transfer sheet 4 wound around the core is arranged at two positions in the front and rear, and a stepping motor 6 is arranged in front of the roll sheet supporting roller 5 at the lower part of the rear part (left side in the figure) in the frame 2. It is set up.

As shown in FIG. 2, the stepping motor 6
The power of the first large-diameter gear and the small-diameter gear are coaxially formed.
And the second reduction gears 7 and 8 reduce the speed,
The gear 10 with a ball clutch fitted on the shaft 9a of the platen roller 9 above the reduction gear 8 is meshed with the large diameter gear of the second reduction gear 8 and fitted on the shaft 11a of the front sprocket wheel 11. 12 meshes with the small diameter gear of the second reduction gear 8.

By setting the outer diameter dimension ratio of the platen roller 9 and the sprocket wheel 11, the reduction gear 8 and the reduction ratio of the ball clutch gear 10 and the gear 12, the peripheral speed of the platen roller 9 under no load is determined by the sprocket wheel 11. It is set higher than the peripheral speed of.

The gear 10 with a ball clutch has a known structure, and although not shown in the drawings, a plurality of holes are provided radially on the outer peripheral surface of a fixed disc fitted on the platen roller shaft 9a to form springs and balls. A hole into which a ball fits is provided on the inner peripheral surface of the gear that is inserted and externally fitted to the fixed disc. The torque limit value of the gear with ball clutch 10 is set by the constant of the spring, and the rotation torque of the platen roller 9 is limited to the set value regardless of the rotation torque transmitted to the gear. The torque limit value of the ball clutch-equipped gear 10 used here is set to be equal to or less than the transfer load of the transfer sheet and the ink ribbon.

The pair of left and right sprocket wheels 11 connected by the sprocket wheel shafts 11a are positioned to engage with perforations provided on both side edges of the transfer sheet 4. Further, a vertically movable sheet pressing roller 13 is disposed above the pair of left and right sprocket wheels 11, and the sheet pressing roller 13 is urged by a spring (not shown) to flatten the outer peripheral surface of the sprocket wheel 11. The transfer sheet 4 which is pressed against and is engaged with the sprocket wheel 11 is pinched.

Sprocket wheel 11 in frame 2
The ink ribbon take-up gear 14 projects to the inside of the side plate of the frame 2 at the upper position of the ink ribbon take-up gear 14 and the ink ribbon take-up gear 14 shown in FIG.
The take-up spool 16 is driven by meshing with the gear 16a of the take-up spool 16. The pulley 1 is attached to the gear shaft 14a of the ink ribbon take-up gear 14 protruding to the outside of the frame 2.
7 is fitted, and a belt 19 is hung on the pulley 17 and the pulley 18 fitted on the shaft of the second reduction gear 8 to transmit the driving force to the ink ribbon winding gear 14.

Behind the ink ribbon take-up gear 14, there is provided a gear 22 with a brake which meshes with a gear 20a of a supply spool 20 of an ink ribbon cartridge 15 and gives a back tension to the ink ribbon 21.

A micro switch 24 is attached to the back surface of a transfer sheet guide plate 23 provided behind the platen roller 9, and a button 24a at the tip of the operating lever of the micro switch 24 is provided on the transfer sheet guide plate 23. Through a hole (not shown). When the transfer sheet 4 is being supplied to the platen roller 9, the transfer sheet 4 causes the button 24 a of the micro switch 24 to be pressed.
When is pressed and the end of the transfer sheet 4 passes the transfer sheet guide plate 23, the button 24a projects upward and a sheet end signal is output.

An ink ribbon cartridge loading chamber 25 is formed in the upper cover 3, and the thermal head 2 provided in the front and rear intermediate portion of the ink ribbon cartridge loading chamber 25.
6 is a supply spool 2 of the ink ribbon cartridge 15
It is located between 0 and the take-up spool 16.

FIG. 3 shows the ink ribbon cartridge 15, and FIG. 3A shows a state in which the upper case 27 of the cartridge is removed. As shown in the figure, the supply spool 20 and the take-up spool 16 are pivotally supported in the front and rear of the lower case 28 having a rectangular frame shape, and the ink ribbon 21 is wound from the rear supply spool 20 to the front take-up spool 16. Taken. Gears 20a and 16a formed at both ends of the supply spool 20 and the take-up spool 16 mesh with the above-described brake gear 22 and the ink ribbon take-up gear 14, respectively. Locking claws 2 are provided on both front and rear ends of the lower case 28.
9, 30 are provided, and the locking claws 29, 30 are provided in the ink ribbon cartridge loading chamber 25 of the upper cover 3 shown in FIG.
The ink ribbon cartridge 15 is mounted by being fitted to the engaging portion provided on the.

FIG. 4 shows the transfer sheet 4, which is provided with an adhesive layer on the back surface of a sheet film 31 made of polyethylene resin or vinyl chloride resin and adhered to a base release paper 32, and both left and right edge portions with respect to the feeding direction. Are provided with circular perforations 33 at equal intervals.

As shown in FIG. 1, the roll of the transfer sheet 4 is loaded on the roll sheet supporting roller 5, and the transfer sheet 4 is loaded.
Platen roller 9 and sprocket wheel 1 at the beginning of
1 is pulled out to the front sheet discharge port 34, the perforation 33 is meshed with the sprocket wheel 11, and the upper cover 3 having the ink ribbon cartridge 15 mounted thereon is closed, as shown in FIG. The platen roller 9 presses the transfer sheet 4 and the ink ribbon 21 together.

When printing is executed, the print data is sequentially transferred from the control unit (not shown) to the thermal head 26, and at the same time, the stepping motor 6 is driven in synchronization with the thermal head 26, and the transfer sheet 4 and the ink ribbon 21 are moved to the platen roller. 9, the ink ribbon 21 is wound on the winding spool 16, and the transfer sheet 4 is discharged by the sprocket wheel 11 through the sheet discharge port 34.

At this time, since the rotation torque of the platen roller 9 is limited to less than the feeding load of the transfer sheet 4 and the ink ribbon 21 by the gear 10 with a ball clutch,
The platen roller 9 idles with respect to the platen roller shaft 9a that rotates at a rotation speed higher than that of the sprocket wheel 11, and rotates in synchronization with the feed amount of the transfer sheet 4 sent by the sprocket wheel 9.

Therefore, the peripheral speed of the platen roller 9 is automatically controlled to the same speed as the peripheral speed of the sprocket wheel 11 so that the transfer sheet 4 and the ink ribbon 21 are not loosened. Further, since the platen roller 9 and the sprocket wheel 11 are interlocked to feed the transfer sheet 4 and the ink ribbon 21, the feeding load of the transfer sheet 4 on the sprocket wheel 11 is extremely small, and the perforations 33 are not deformed.

The present invention is not limited to the above-mentioned embodiment, but various modifications such as using a friction clutch as the torque limiter of the platen roller 9 are possible, and the present invention is not limited to these modifications. It goes without saying.

[0027]

As described above in detail, in the thermal transfer printer apparatus of the present invention, the transfer sheet and the ink ribbon are not loosened between the platen roller and the sprocket wheel, and the perforation of the transfer sheet is excessive. The perforation will not be deformed due to strong tension. Therefore, no deviation occurs in the feed amount between the sprocket wheel and the platen roller, the running stability and running accuracy of the sheet and the ink ribbon are improved, and it is possible to contribute to the improvement of printing quality.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing a thermal transfer printer device of the present invention with an upper cover opened.

FIG. 2 is a partially cutaway side view of a sheet feeding mechanism of the thermal transfer printer device shown in FIG.

3A and 3B show an ink ribbon cartridge, FIG. 3A is a plan view with an upper case removed, and FIG. 3B is a side view with an upper case attached.

FIG. 4 shows a transfer sheet, (a) is a plan view and (b) is a sectional view.

FIG. 5 is an explanatory diagram showing a printing state of the thermal transfer printer device shown in FIG.

[Explanation of symbols]

 1 Thermal Transfer Printer 2 Frame 3 Top Cover 4 Transfer Sheet 9 Platen Roller 10 Gear with Ball Clutch 11 Sprocket Wheel 15 Ink Ribbon Cartridge 17, 18 Pulley 19 Belt 21 Ink Ribbon 26 Thermal Head 33 Perforation

Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display area B65H 23/188 B41J 3/20 117A

Claims (1)

[Claims] 1. A thermal transfer printer device comprising a sprocket wheel for feeding a sheet which is rotated by a motor, a platen roller, an ink ribbon take-up reel shaft, and a thermal head which is in pressure contact with the platen roller. By engaging the sprocket wheels with perforations arranged side by side along the longitudinal side edges, and pinching the transfer sheet and the ink ribbon by the platen roller and the thermal head, the platen roller and the sprocket wheel are In a thermal transfer printer device for interlockingly sending a transfer sheet to thermally transfer the ink of an ink ribbon to the transfer sheet, a gear (10) is attached to a shaft of the platen roller (9) via a torque limiter such as a friction clutch or a ball clutch. ) Is mounted and front through the reduction gear unit The platen roller (9) is driven by a motor, and the peripheral speed of the platen roller (9) when no load is applied is set to be higher than the peripheral speed of the sprocket wheel (11) to limit the torque of the torque limiter. A thermal transfer printer device, wherein a value is set to be equal to or less than a feeding load of the transfer sheet (4) and the ink ribbon (21).