JPH09272213A - Line thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent print unevenness from occurring by removing dust sticking to an ink film on a supply side before printing. SOLUTION: This line thermal printer is equipped with a cleaning roller which is mounted, in freely rotating manner, on the cassette base 32 of an ink film cassette 30 containing an ink film 3 and is of such a structure that a polyurethane sponge of an ultrafine continuous porous form produced by a liquid sintering is junctioned to the surface of a metal shaft, and further, is rotated following the transport of the ink film 3, uniformly pressing the surface of the film 3 on the ink film 3 supply side of a recording head, when the ink film 3 is supplied to the recording head 51. In addition, the cassette base 32 is of such a structure that it can be mounted by engaging and locking both ends of the cleaning roller 31 and also can be freely detached.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line thermal printer which presses a recording head against a platen roller via a recording medium and an ink film to transfer the ink applied to the ink film to the recording medium by heat generated from the recording head. In particular, the present invention relates to a line thermal printer that removes dust or the like adhering to the ink film on the supply side before printing to prevent uneven printing.

[0002]

2. Description of the Related Art Conventionally, in a line thermal printer of this type, a technique of removing dust and the like adhering to the surface of an ink film before being supplied to a recording head is disclosed in, for example, Japanese Patent Laid-Open No. Hei 4-
No. 221670. This apparatus has a cleaning roller having adhesiveness on the supply side of the recording head, and removes dust and the like adhering to the surface of the ink film by bringing the ink film into contact with the circumference of the cleaning roller. As a result, dust or the like attached to the ink film enters between the recording head and the ink film during printing, which damages the recording head,
Alternatively, the purpose of preventing obstacles such as breaking the ink film has been achieved.

In this embodiment, the recording head is pressed against the platen roller via the ink film and the recording medium,
A recording system is described in which the ink film and the recording medium are conveyed by independent drive mechanisms, and the ink applied to the ink film is transferred to the recording medium by heat generated from the recording head.

The ink film of this recording apparatus is obtained by winding a continuous base film having a width larger than the printing range, coated with ink, on two cylinders, a supply side and a winding side, and rotating the winding side cylinder. To convey the ink film.

In this cassette, the cleaning roller has a length equal to or larger than the width of the ink film and is arranged between the recording head and the ink film supply side cylinder.
The surface of this cleaning roller has an adhesive property such as a silicone rubber coating, and by contacting the ink film before reaching the recording head, the adhesive force of the cleaning roller removes dust and the like adhering to the ink film. Further, this roller is a driven roller which is rotated by the tension generated in the ink film.

[0006]

The conventional line thermal printer described above removes dust and the like adhering to the ink film by pressing the ink film against the circumferential surface of the cleaning roller having adhesiveness. On the other hand, this cleaning roller is a driven roller that rotates due to the tension generated in the ink film, but cannot move in the direction perpendicular to the transport direction of the ink film. Further, it is difficult for the ink film to move on the cleaning roller in the direction perpendicular to the transport direction due to the adhesive force of the cleaning roller.

Therefore, as shown in FIG. 6 (A), the ink film 3 has a winding force F for winding the ink film 3.
It is necessary to press the cleaning roller in a state in which the cleaning roller is completely parallel to the above direction and is slack in the entire width of the cleaning roller.

When the ink film is conveyed in a state where this condition is not satisfied, as shown in FIG. 6 (B), the ink film 3 is wound in parallel with the winding direction F by the winding force F of the ink film 3 and is cleaned. A force S is applied to the ink film 3 near the cleaning roller 9 to correct the roller 9 so that the roller 9 has no slack in its entire width.

When the cleaning roller 9 is not adhesive, the ink film 3 shown in FIG. 6 (B) moves on the cleaning roller 9 by the force S and is corrected to the state shown in FIG. 6 (A).

However, when the cleaning roller 9 is sticky, the force S causes wrinkles on the ink film 3 near the cleaning roller 9 due to the stickiness. When a printing operation is performed on the ink film 3 conveyed in this state, when the wrinkles of the ink film 3 expand to the recording head portion, the ink film 3 is broken by the pressing force of the recording head, and at this portion, the recording medium. There is a problem in that there may be a problem that the ink is not transferred to.

Further, when the ink film is replaced, especially when the ink film is attached, the ink film easily sticks to the cleaning roller due to the adhesiveness of the cleaning roller,
There is a problem in that it is very difficult to attach the ink film in a completely parallel state with respect to the transport direction of the ink film without wrinkles.

An object of the present invention is to provide a line thermal printer capable of preventing uneven printing by removing dust and the like adhering to the ink film on the supply side by a non-adhesive cleaning roller before printing.

[0013]

A line thermal printer according to the present invention presses a recording head against a platen roller via a recording medium and an ink film, and heat generated by the recording head causes the ink applied to the ink film to the recording medium. In a line thermal printer for transferring, a shaft structure is rotatably attached to a cassette base of an ink film cassette in which an ink film is installed, and has a shaft structure whose surface is covered with a member having an ultrafine continuous pore structure,
A cleaning roller is provided which uniformly presses the surface of the ink film on the ink film supply side of the recording head and rotates as the ink film is conveyed.

Further, one specific example of the cleaning roller has a structure in which a polyurethane sponge having an ultrafine continuous pore structure produced by a liquid sintering method is joined to the surface of a metal shaft.

The surface structure of the fine pores of the cleaning roller removes dust and the like adhering to the ink film by scooping with the fine pores when contacting the ink film.

The cassette base has a structure in which both ends of the cleaning roller are mounted by fitting and locking. Therefore, the cleaning roller can be attached to and detached from the cassette base.

[0017]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a functional block diagram showing an embodiment of the present invention. The line thermal printer shown in FIG. 1 has a recording medium suction unit 10 for the recording medium 1, a recording medium transporting unit 20, an ink film cassette 30, a film winding mechanism unit 40, and a recording head mechanism unit 50 as mechanical units. By rotating the recording medium transport unit 20 around the hinge shaft 2, the recording medium transport unit 20 exhibits the function of transporting the recording medium 1 in the closed state, and can be removed from the apparatus main body in the opened state.

Also, in this opened state, the ink film cassette 30 can be removed and the ink film 3 can be removed from the ink film cassette 30. The ink film cassette 30 includes a cleaning roller 31 that comes into contact with the surface of the ink film 3 that is wound from the film supply cylinder 3-1 to the film winding cylinder 3-2.

The present invention is different from the conventional one in that the cleaning roller 31 has the metal shaft 3 as shown in FIG.
That is, the polyurethane sponge 31-2 having an ultrafine continuous pore structure produced by the liquid sintering method is bonded to the surface of 1-1.

First, the recording medium suction unit 10 will be described with reference to FIGS.

The recording medium suction unit 10 is composed of a paper guide 11, a hopper plate 12, a pressure spring 13, and a pick roller 14 as shown in the drawing. Paper guide 11 and hopper plate 1
Reference numeral 2 holds the loaded recording medium 1. The pressure spring 13 presses the hopper plate 12 against the pick roller 14 via the recording medium 1. The pick roller 14 is rotated in a direction indicated by an arrow by a drive motor (not shown) to feed the loaded recording media one by one to the recording medium transport unit 20.

Next, referring to FIG.
Description will be made with reference to FIG. 2 and FIG.

The recording medium transport unit 20 includes a second roller 2
1, an idle roller 22, a platen roller 23, a main roller 24, a pressure roller 25, and a discharge roller 26, and the pick roller 14 conveys the recording medium 1 fed from the recording medium suction unit 10.

A second roller 21 and an idle roller 22, a main roller 24 and a pressure roller 25.
And are conveyed by being rotated with the recording medium 1 sandwiched therebetween. The platen roller 23 includes the recording head mechanism unit 5
The recording head 51 is pressed against the recording medium 1 and the ink film 3 by 0, and the recording medium 1 is conveyed by rotating.

Second roller 21, platen roller 2
3, the main roller 24, and the discharge roller 26 are shown in FIG.
The rotation of the line feed motor 60 is controlled by the reduction gears 61 and 62, the idle gear 63, the platen gear 64, the main roller gear 65, and the idle roller gear 6 as shown in FIG.
6, the friction gear 67, the second roller gear 68, the timing belt 70, and the discharge roller pulley 71.

Next, the ink film cassette 30 will be described with reference to FIGS. 1, 2 and 5.

As shown in detail in FIG. 5, the ink film cassette 30 includes an ink film 3 wound around a film supply cylinder 3-1 and a film winding cylinder 3-2, a cassette base 32 for mounting a cleaning roller 31, and a cassette. It is composed of a cover 33 and a back tension spring 34.

The ink film 3 is produced by applying ink to a continuous polyester base film having a width wider than the printing range, and wound around a hollow film supply cylinder 3-1 and a film winding cylinder 3-2. . There are a plurality of types of ink film 3 used for the cleaning roller 31, and for example, the thickness of the base film is 3.5 to 6
The thickness of the ink film 3 is 1 μm to 4 μm, and the average thickness of the ink film 3 is 7 μm, which is very thin.

The ink film 3 is wound around the film supply cylinder 3-1 so that the base film is on the outer side before printing, and on the other hand, the base film is on the inner side after printing, on the film winding cylinder 3-2. It is rolled. The film supply cylinder 3-1 and the film take-up cylinder 3-2 are mounted on the cassette base 32, to which the cleaning roller 31 is mounted, from above in a predetermined position. At the time of mounting, as shown in FIG. 5, the film supply cylinder 3-1 is set to the cassette base 32.
Placed on top of the back tension spring 34.

The arrow view shown in FIG. 5 shows the film supply cylinder 3.
-1 and the film winding cylinder 3-2 show one end face of each, and a concave groove is formed on the vertical axis of the cylinder on the plane perpendicular to the straight line passing through the central axis. The concave groove of the film take-up cylinder 3-2 has a film take-up mechanism section 40 described later.
It is a connecting part by fitting with.

The cleaning roller 31 is the metal shaft 3
A polyurethane sponge 31-2 having an ultrafine continuous pore structure produced by a liquid sintering method is joined to the surface of 1-1. This polyurethane sponge 31-
The dust and the like adhering to the ink film 3 come into contact with the ink film 3 and are scooped up by the fine pores to be trapped in the body, so that the dust and the like adhering to the ink film 3 can be removed.

The cleaning roller 31 is used for the recording head 5.
1 and the film supply cylinder 3-1 as shown in FIG. 2, and is mounted on the cassette base 32 so as to come into contact with the surface of the ink film 3 which is the outer peripheral surface of the film supply cylinder 3-1. . The cleaning roller 31 has one end of a central shaft having a small diameter provided at both end portions of the cassette base 3
2 is fitted into the base hole 32-1 provided on one surface of
The other end is positioned by dropping it from above the base U groove 32-2 provided on the other surface of the cassette base 32.

As described above, the cassette base 32 has a predetermined size and location for accommodating the film supply cylinder 3-1 and the film winding cylinder 3-2 wound around the ink film 3, and the film supply cylinder 3-1. A back tension spring 34 is provided at both ends of the bottom surface where is located, and a base hole 32-1 for mounting the cleaning roller 31 and a base U groove 32-2 are provided at a position near the film supply cylinder 3-1.

Further, the entrance portion of the base U groove 32-2 is made narrower than the diameter of the metal shaft 31-1 by about 0.2 mm to prevent the cleaning roller 31 from falling off. Therefore, the cleaning roller 31 can be easily attached and detached, and can be easily replaced when the function of the cleaning roller 31 deteriorates.

As shown in FIG. 5, the cassette cover 33 is located above the film supply cylinder 3-1 attached to the cassette base 32, and the outer edge of the cassette cover 33 is the cassette base 3.
It has a structure in which an axis is applied to the outer edge of 2 and can be opened and closed by rotating around the axis. Therefore, since the cassette cover 33 covers the outer peripheral surface of the ink film 3 on the supply side,
It is possible to prevent dust and the like from adhering to some extent. However, since the cassette cover 33 does not completely seal the ink film 3 on the supply side, dust or the like is adsorbed on the outer peripheral surface of the ink film 3 on the supply side due to static electricity charged on the ink film 3 even when left standing for a long time. It is inevitable to do.

The back tension spring 34 sandwiches both ends of the film supply cylinder 3-1 with the arc-shaped portion of the cassette cover 33 in a state where the ink film 3 is mounted, so that the film winding mechanism section 40 described later will be described.
A load is applied to the rotation of the film supply cylinder 3-1 that rotates.

Next, the film winding mechanism 40 will be described with reference to FIGS. 1, 2 and 4.

The film winding mechanism section 40 includes a drive motor 4
The rotation of 1 is transmitted to the worm gear 42, the reduction gear 43, the film feed gear 44, and the film feed hub 45. On the open side of the film feed hub 45,
The above-mentioned film take-up cylinder 3-2 is provided with a convex projection that fits into a concave groove provided on one end surface of the film take-up cylinder 3-2, and the convex projection is connected to the concave groove to feed the film. The ink film 3 is conveyed by transmitting the rotation of the hub 45 to the film winding cylinder 3-2.

The recording head mechanism section 50 has a recording head 51, as shown in FIG.
Is pressed against the platen roller 23 via the recording medium 1 and the ink film 3, and the ink applied to the ink film 3 is transferred to the recording medium 1 by the heat generated from the recording head 51.

Next, the operation of removing dust and the like by the cleaning roller 31 will be described with reference to FIG. 2 showing the printing state of the apparatus.

In the printing state, the recording head mechanism section 5 described above is used.
The recording head 51 is pressed against the platen roller 23 via the recording medium 1 and the ink film 3 by 0. The recording medium 1 is moved in the direction of the arrow shown in FIG.
In the same manner as the recording medium 1, the ink film 3 is conveyed in the direction toward the recording head 51 by rotating the film winding cylinder 3-2 in the direction indicated by the arrow by the film winding mechanism 40 described above. Be transported.

At this time, the film supply cylinder 3-1 also rotates with the rotation of the film take-up cylinder 3-2, but as described above, the film supply cylinder 3-1 is rotated by the back tension spring 34 of the ink film cassette 30. Since a load is applied to the ink film 3, a tension is generated in the ink film 3 between the film supply cylinder 3-1 and the recording head 51 in the winding direction. Since the ink film 3 is pressed against the cleaning roller 31 by this tension, the cleaning roller 31 rotates as the ink film 3 is conveyed, and before the dust or the like attached to the surface of the pressed ink film 3 is printed, that is, It is removed before it reaches the recording head 51.

In the above description, the cleaning roller is formed by joining the surface of the metal shaft with the polyurethane sponge having the ultrafine continuous pore structure produced by the liquid sintering method. Other members may be used as long as they have a fine pore structure that can be scooped up on the outer peripheral surface.

[0045]

As described above, according to the present invention, a cleaning roller having a polyurethane sponge having an ultrafine continuous pore structure bonded to the outer peripheral surface is disposed between the recording head and the film supply cylinder, and the ink film is formed. A line thermal printer is obtained in which the entire surface of the cleaning roller is brought into contact with a part of the circumference of the cleaning roller, and the fine pores on the surface of the cleaning roller capture and remove dust and the like adhering to the ink film.

With this structure, since dust and the like adhering to the ink film before reaching the position of the recording head is removed, printing defects due to dust and the like present between the recording head and the ink film are improved and the ink film is not Since the surface of the cleaning roller that comes into contact with it is not sticky,
The effect that the ink film can be easily replaced is obtained.

[Brief description of drawings]

FIG. 1 is an overall structural explanatory view showing an embodiment when an ink film cassette of the present invention is mounted.

FIG. 2 is an overall structural explanatory view showing an embodiment of a recording operation of the invention.

FIG. 3 is a partial structural explanatory view showing an embodiment of a recording medium carrying mechanism in FIG.

FIG. 4 is a partial structural explanatory view showing an embodiment of the film winding mechanism in FIG.

5 is a partial structural explanatory view showing an embodiment of the ink film cassette in FIG. 2. FIG.

FIG. 6 is a model explanatory diagram of an ink film winding state.

[Explanation of symbols]

 1 Recording Medium 3 Ink Film 3-1 Film Supply Cylinder 3-2 Film Winding Cylinder 10 Recording Medium Suction Section 20 Recording Medium Conveying Section 23 Platen Roller 30 Ink Film Cassette 31 Cleaning Roller 31-1 Metal Shaft 31-2 Polyurethane Sponge 32 Cassette Base 32-1 base hole 32-2 base U groove 33 cassette cover 34 back tension spring 40 film winding mechanism section 50 recording head mechanism section 51 recording head

Claims (3)

[Claims] 1. A line thermal printer in which a recording head is pressed against a platen roller via a recording medium and an ink film to transfer the ink applied to the ink film to the recording medium by heat generated from the recording head, the ink film being internally provided. It has a shaft structure that is rotatably mounted on a cassette base of an ink film cassette and has a surface covered with a member having an ultrafine continuous pore structure, and uniformly presses the surface of the ink film on the ink film supply side of the recording head. A line thermal printer comprising a cleaning roller that rotates according to the conveyance of the ink film. 2. The line thermal according to claim 1, wherein the cleaning roller has a structure in which a polyurethane sponge having an ultrafine continuous pore structure produced by a liquid sintering method is bonded to the surface of a metal shaft. Printer. 3. The line thermal printer according to claim 1, wherein the cassette base has a structure in which both ends of a cleaning roller are mounted by fitting and locking.