JPS61268468A - Thermal printer - Google Patents

Abstract

PURPOSE:To enable the prevention of wrinkles by a construction wherein an ink film guide member fitted to one end of a thermal head or an ink cartridge is made to contact with the feeding and carrying the surface of a rolled ink film. CONSTITUTION:When a thermal head 1 is put in pressure-contact with a platen 4, an ink film guide member 15 fitted to one end of this head 2 comes in contact with an ink film 7. Thereby the central portion 7b of the ink film 7 is given a larger tension thant the opposite end portions 7a thereof, wrincles are stretched by a circular-arc ridge 16 and prevented from spreading toward the inside of a feeder shaft 8, and thus excellent printing can be obtained. This thermal head 1 has a construction in which a number of heating bodies 13 are provided in a line near the end portion and the ink film guide member 15 having the circular-arc ridge 16 which contacts with the ink film 7 is fixed on the ink film feeder shaft 8 side by setscrews 14 or the like. In this way, an excellent quality of printing can be obtained by a simple construction.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a thermal printer that performs thermal recording on a recording medium using a roll-shaped ink film housed in a cartridge, and particularly relates to a method for preventing wrinkles occurring in the ink film. The present invention relates to such a thermal printer having an ink film guide member useful for the purpose of the present invention.

[Background of the invention]

A thermal printer (also called a thermal transfer type) uses an ink film made by coating a thin base paper (film) with heat-melting or heat-sublimating ink, and uses a heat-sensitive head equipped with a heating resistor to print. After the ink-applied side of the film is brought into contact with photographic paper, both the film and the photographic paper are pressed against a platen, and a desired print is obtained on the photographic paper by selectively heating the heating resistor using a recording signal. .

At this time, since the thinner the base paper (film) is, the higher the thermal efficiency is, the ink film used is several μm thick. Furthermore, in the case of such a transfer printer, since the ink film is disposable, it is necessary to use a new ink film each time printing is performed.

On the other hand, in order to increase the printing speed, a thermal line head in which a large number of heating resistors are arranged in a straight line has been used as a thermal head. In a printer using a thermal line head, the width of the ink film used is increased, and an ink film having the same size as the recording paper is used.

In many cases, such thin and large ink sheets are inconvenient to handle as they are, so they are formed into a roll and placed in a cartridge as disclosed in Japanese Patent Application Laid-Open No. 56-67278. It is customary.

With this configuration, it has become very easy to attach and detach the rolled ink film to and from the printer.
Generally speaking, printers have no choice but to simplify the conveyance path of the ink film.When using a thin and wide ink film, wrinkles may form on the ink film during conveyance, resulting in a significant drop in print quality. There was a problem.

A detailed explanation will be given below with reference to the drawings.

FIG. 7 is an explanatory diagram showing an outline of the configuration of a conventional thermal transfer printer. In the figure, a thermal head 1 equipped with a large number of heating resistors is mounted on a head arm 3 that swings about a fulcrum 2, and is pressed against a platen 4 by a biasing mechanism (not shown). The platen 4 rotates about an axis 5 in the direction of an arrow 6.

The ink film 7, which is made by coating a thin base paper such as a polyester film with heat-sensitive ink such as heat-melting or heat-sublimating ink, is in the form of a roll and is wound from a supply shaft 8 to a take-up shaft 9. , is sandwiched between the thermal head 1 and the platen 4, and is conveyed in the direction of the arrow 10 as the platen 4 rotates.

A recording paper (not shown) is sandwiched between the ink film 7 and the platen 4, and ink is transferred onto the recording paper by energizing the thermal head 1. The peeling roller 11 is brought into pressure contact with the platen 4 from the head arm 3 by a biasing mechanism (not shown), and improves the separation between the ink film 7 and the recording paper after transfer. Cartridge 12 indicated by dashed line
The ink film 7 is transported by its supply shaft 8 and take-up shaft 9.
The thin ink film 7
It has good handling properties.

In the above-described configuration, when the heat-sensitive heater 1 is energized to print an image, the ink film 7 corresponding to the portion that generates heat due to the energization contracts due to the heat, and the supply shaft 8 of the ink film 7
Wrinkles may appear on the sides. In many cases,
The generated wrinkles are directly transferred between the thermal head 1 and the platen 4, causing wrinkle-like printing defects in the printing results, thereby deteriorating the printing quality.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal printer using a roll-shaped ink film with means for preventing wrinkles from forming on the ink film, in other words, to provide a thermal printer that uses a roll-shaped ink film, in order to solve the problems in the prior art described above. The purpose of the present invention is to provide a thermal printer.

[Summary of the invention]

In order to achieve the above object, in the present invention, an ink film guide member attached to one end of a thermal head or an ink cartridge is brought into contact with a feeding surface of a roll-shaped ink film, and the contact surface is curved. Tension is applied so that the film curves in a direction intersecting the direction of transport, thereby preventing wrinkles from forming.

[Embodiments of the invention]

The present invention will now be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram showing a general configuration of an embodiment of the present invention. In this figure, the same parts as in FIG. 7 are given the same reference numerals. In addition, a film guide member 15 is attached to one end of the thermal head 1. 7
7b is the center portion of the film.

In FIG. 1, when the heat-sensitive head 1 is pressed against the platen 4, the ink film guide member 15 attached to one end of the head 1 comes into contact with the ink film 7, so that the center part 7b of the ink film 7 is different from both ends 7a. The wrinkles are smoothed out by the arcuate ridges 16 (not shown, described later) on the film contacting surface of the guide member 15, and the spread of the wrinkles to the supply shaft 8 side is prevented. No, good prints can be obtained.

FIG. 2 is a perspective view of the guide member 15 in FIG. 1, looking up from diagonally below. In the same figure, 13
14 is a heating element, 14 is a set screw, 16 is a ridge wire, and 17 is a wiring board.

In FIG. 2, on the lower surface of the thermal head 1, many heating elements 13 are arranged in a row near the end thereof, and the ink film 7 and the recording paper are pressed against the platen 4 at this portion. The supply shaft 8 of the ink film 7 is located on the bottom surface of the thermal head 1.
An ink film guide member 15 is fixed to the side with the ink film guide member 15 by a set screw 14 or the like. The surface of the ink film guide member 15 that comes into contact with the ink film 7 is
As shown in the figure, the ridge line 16 has an arc shape with a large curvature and a convex center. As previously explained, the arcuate film contacting surface of the guide member 15 smoothes out wrinkles on the film and prevents the wrinkles from spreading.

In addition, in FIG. 2, the ink film guide member 1
5 can also serve as a holding member for the wiring board 17 in the thermal head 1.

FIG. 3 is an explanatory diagram showing an outline of the configuration of another embodiment of the present invention;
FIG. 4 is a perspective view of the bottom surface of the thermal head 1 in FIG. 3 when viewed diagonally from below, and FIG. 5 is a perspective view of the cartridge in FIG. 3 when viewed diagonally from above.

In these figures, parts labeled with the same numbers as in FIGS. 1 and 2 indicate the same parts.

In addition, 18 is a positioning member, 19 is a convex portion, 20 is a hole in the cartridge 12, 21 is a hinge portion, 22 is a guide member, and 23 is an end thereof.

Please refer to FIGS. 3 to 5. In this example, the fourth
As shown in the figure, a positioning member 18 is attached to the lower surface of the heat-sensitive heating pad 1, and a convex portion 19 is further formed on the positioning member 18.

On the other hand, as shown in FIG. 5, an ink film guide member is inserted into the hole 20 in the center of the cartridge 12 containing the ink film 7 into which the thermal head 1 is inserted, through a flexible hinge part 21 relative to the main body of the cartridge 12. 22 have been made. End portion 2 of ink film guide member 22
3 has an arc shape with a large curvature and a convex center.

Fig. 3 shows a thermal head 1 having a structure as shown in Fig. 4.
5 shows how the ink film 7 is regulated by the cartridge 12 having the structure shown in FIG. That is, in FIG. 3, when the thermal head 1 is pressed against the platen 4, the convex portion 19 of the positioning member 18 comes into contact with the ink film guide member 22, producing the same effect as the previously described embodiment.

In this embodiment as well, the positioning member 18 can also serve as a holding member for the wiring board 17 in the thermal head 1. Further, in this embodiment, the ink film guide member 22 is planar, but the same effect can be obtained even if the end portion 23 is formed into a spherical shape or a ship bottom-shaped convex portion toward the ink film, as shown in FIG. be able to.

In each of the embodiments described above, the ink film guide member 22 is made of a conductive material and is grounded to the printer main body chassis (not shown).
It is also possible to effectively eliminate static electricity.

〔Effect of the invention〕

As explained above, according to the present invention, by adding a simple configuration to a thermal printer, it is possible to effectively prevent wrinkles that occur when printing with a thermal head in a thin roll-shaped ink film. .

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an outline of the configuration of an embodiment of the present invention, FIG. 2 is a perspective view of the guide member in FIG. 1 viewed diagonally from below, and FIG. 3 is a configuration of another embodiment of the present invention. An explanatory diagram showing an overview; FIG. 4 is a perspective view of the bottom surface of the thermal head in FIG. 3 when looking up diagonally from below; FIG. 5 is a perspective view of the cartridge in FIG. 3 when looking down diagonally from above;
FIG. 6 is a perspective view showing a modification of the cartridge shown in FIG. 5, and FIG. 7 is an explanatory diagram showing an outline of the configuration of a conventional thermal printer. Explanation of symbols 1... Thermal head, 4... Platen, 7... Ink film, 12... Cartridge, 15... Ink film guide member, 22... Ink film guide member Representative Patent attorney Namiki Akio 1st drawing 2nd drawing 16YIE East 3rd drawing g4 drawing wcs drawing 6th figure 't8 Kaisho 61-268468 (5) Fig. 7

Claims (1)

[Claims] 1) The ink film that is fed out from the supply shaft side in the cartridge and wound onto the take-up shaft side is pressed against the platen by a thermal head during its transport, and the platen and the ink film are brought into contact with each other. In a thermal printer that performs thermal recording on a recording medium interposed in between, a guide that applies tension to the ink film fed out from the supply shaft side from the thermal head side on the way to a position where the film contacts the platen. A thermal printer characterized in that a guide member is provided as a member, the film contacting surface of which is curved and which applies tension by curving the film along a direction intersecting the transport direction thereof. 2) A thermal printer according to claim 1, wherein the guide member is attached to one end of the thermal head. 3) In the thermal printer according to claim 1, the guide member is a plate member having one end flexibly attached to the frame of the cartridge and the other end forming a curved film contacting surface. , a positioning member attached to one end of the thermal head and acting on the plate member to bring the film contacting surface into contact with the film when the head presses the ink film against the platen. A thermal printer.