JP2001096781A - Thermal head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the generation of wrinkles in a thermal transfer ribbon caused by the non-uniformity of the peeling force of the thermal transfer ribbon with a medium to be printed temporarily bonded by solidified ink in the lateral direction of the ribbon generated when printing is applied to the medium to be printed on the side biased to the lateral direction of the thermal transfer ribbon 3. SOLUTION: A thermal head is constituted so that printing is performed by the elongated heating resistor 6 arranged on a substrate 7 extending in the lateral direction of a travelable thermal transfer ribbon 3 and capable of pressing the thermal transfer ribbon 3 and a medium 9 to be printed to a platen 4. The thermal transfer ribbon 3 and the medium 9 to be printed are pressed to the surface of the platen 4 by the stepped part 16 provided on the upstream side in the traveling direction of the thermal transfer ribbon 3 from the heating resistor 6 on the substrate 7. The stepped part 16 is extended at least in the lateral direction of the thermal transfer ribbon 3 and formed so as to be made almost equal to or longer than the width of the thermal transfer ribbon 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer system in which a heating resistor arranged in a line on a substrate is pressed in the width direction of a thermal transfer ribbon while selectively energizing the heating resistor. The present invention relates to a structure of a thermal head in which ink on a ribbon is melted by Joule heat, and the melted ink is transferred to a printing medium on a platen to perform printing.

[0002]

2. Description of the Related Art In a thermal head of this type, a glassy glaze layer is formed as a heat insulating layer on the surface of a ceramic substrate, and then a heating resistor element layer and a power supply layer are formed thereon. A protective layer made of glass is formed to prevent oxidation of the heating resistor element layer and prevent abrasion by the thermal paper. A metal support plate (head holder plate) is attached to the back side of the substrate so as to contribute to strength maintenance and heat radiation.

[0003] In a thermal transfer printing apparatus,
The print medium and the thermal transfer ribbon are stacked on the platen, and the heating element of the thermal head is pressed against the platen from above, and the thermal transfer ribbon is moved along with the difference movement while relatively moving the print medium and the thermal head. Run, selectively energize a predetermined portion corresponding to a print pattern among a large number of heating resistor elements formed at a fine pitch constituting the heating resistor, to joule the ink on the running thermal transfer ribbon. The ink is melted by heat, and the melted ink is transferred to a printing medium on a platen to perform printing.

Therefore, on the downstream side of the thermal transfer ribbon from the printing portion (ink melting portion), in a direction where the melted ink adheres to the printing medium and solidifies after the ink has solidified, the direction in which the thermal transfer ribbon is peeled off from the printing medium. The direction of travel of the thermal transfer ribbon with respect to the printing medium is changed.

[0005]

However, when printing is performed using one half in the width direction of the thermal transfer ribbon housed in the ribbon cassette, and when the end of the thermal transfer ribbon is used, the ribbon cassette is used upside down ( In the case of the so-called reciprocating use of the thermal transfer ribbon) or printing in the full width of the thermal transfer ribbon while traveling in one direction, the width of the thermal transfer ribbon may be shifted to one side of the thermal transfer ribbon. When printing is performed only at a position deviated in one of the directions, the force (peeling force) for peeling the thermal transfer ribbon adhered by the ink solidified only on the printing side from the printing medium (peeling force) is the same as that of the ink. Since it acts between the solidified portion and the downstream side of the thermal transfer ribbon (the take-up reel side of the thermal transfer ribbon), this peeling force is large or small in the width direction of the thermal transfer ribbon. Will be made, to become unbalanced, the thermal transfer ribbon or meandering running, a crease occurs in the thermal transfer ribbon, there is a problem such as defective printing results, such as thin print spots.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a thermal head which can eliminate the meandering and wrinkles of a thermal transfer ribbon with a simple structure. Is what you do.

[0007]

In order to achieve the above object, a thermal head according to the first aspect of the present invention extends in the width direction of a movable thermal transfer ribbon, and covers the thermal transfer ribbon toward a platen. An elongated heating resistor arranged on a substrate so that the printing medium can be pressed together, and the thermal transfer ribbon and the print-receiving medium are arranged on the substrate in the direction of travel of the thermal transfer ribbon upstream of the heating resistor on the substrate. A step portion sandwiched between the surface of the platen and the step portion, which extends at least in the width direction of the thermal transfer ribbon, and is formed to be substantially equal to or longer than the maximum printing width by the heating resistor. is there.

[0008] The invention described in claim 2 is the first invention.
Wherein a heating resistor is provided on one side of the step portion.

According to a third aspect of the present invention, in the thermal head according to the second aspect, the step portion is formed to have a convexly curved cross section including a location of the heating resistor.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings for preferred embodiments. FIG. 1 is a schematic plan view of a thermal transfer printing apparatus to which the thermal head 1 of the present invention is applied, FIG. 2 is a perspective view of a main part of the thermal head 1, and FIG.

As shown in FIG. 1, the serial type thermal transfer printing apparatus according to the present embodiment has a flat platen 4 and one end rotatable around a support shaft 5 on a side close to the surface of the platen 4. The thermal head 1 includes a thermal head 1 that is pivotally mounted, and a ribbon cassette 2 that stores a thermal transfer ribbon 3 that runs along the front side of the platen 4 on the front end side of the thermal head 1 (a heating resistor 6 described later). Case 2 of ribbon cassette 2
0, the thermal transfer ribbon 3 wound on the supply reel 21
As shown in FIG. 1, an outlet 2 formed on one side of a recess 29 on the front surface of the ribbon cassette 2 via guide bodies 22 and 23.
After being led out once at 4, it enters the entrance 25 on the other side of the recess 29, and is again taken up by the take-up reel 28 by the take-up driving means (not shown) through the guide bodies 26 and 27. Has become. The tape-shaped print medium 9 is transported along the surface of the platen 4 in the direction of arrow A in FIG. 3 (the same direction as the running direction of the thermal transfer ribbon 3) by transport means (not shown).

As shown in FIGS. 2 and 3, the thermal head 1 supports a substrate 7 made of ceramics or the like, and
And a head support plate 10 on which the support shaft 5 is rotatably mounted.
The head support plate 10 is composed of an arm portion 10a on which the support shaft 5 is mounted, and a support portion 10b which is continuously provided offset from the arm portion 10a and faces the recess 29.
The substrate 7 is fixed to the surface of the support portion 32 with an adhesive or the like. The head support plate 10 made of metal such as aluminum has a function of radiating heat generated from the heating resistor 6 to the outside via the substrate 7 in accordance with the printing operation.

The support portion 10 of the head support plate 10
A projecting portion 14 having a convexly curved cross section and being long in the width direction of the thermal transfer ribbon 3 is provided on the leading end side of b.

The heating resistor 6 is disposed on the front end side of the support portion 10b of the head support plate 10 (close to the protruding portion 14) of the surface of the substrate 7, and has a width of the thermal transfer ribbon 3. It is extended so as to extend in the direction. In the thin-film thermal head, a heat-resistant insulating layer made of glass is formed on the surface of a ceramic substrate 7. In the heat-resistant insulating layer, a linear ridge 12 extending in the width direction of the thermal transfer ribbon 3 is formed.
A heating resistor 6 is formed on the uppermost surface of the raised portion 12 in a straight line so as to extend in the width direction of the thermal transfer ribbon 3. Further, a common lead for electric conduction and an individual lead extending on the substrate crossing the heating resistor 6 are formed. A drive I is provided on the base end side of the support portion 10b.
C (integrated circuit) 11 is provided.
1 and the common lead and the individual lead are connected by wire bonding (not shown), and the surfaces of the heating resistor 6 and the lead portion including the raised portion 12 are covered with a glassy protective film (not shown). ), And the portion of the IC 11 and the wire bonding are covered with a protective film 13 such as a synthetic resin. Further, a flat flexible cable 14 connects between each of the ICs 11 and a control unit (not shown) of the printing apparatus. Then, the IC 11 is driven by a command from the control unit, and by selectively energizing the common lead and the individual lead at a position corresponding to the print pattern, the heating resistor is formed at a fine pitch (print dot interval). The element is configured to generate heat. The length of the heating resistor 6 is sufficient to perform printing of a predetermined width, and the width dimension (H1) of the thermal transfer ribbon 3 is substantially equal to or greater than the maximum printing width of the heating resistor 6. It is formed in the width of.

On the front surface of the substrate 7, a regulating member 15 such as a round bar for preventing the back surface of the running thermal transfer ribbon 3 from contacting the protective film 13 at the IC 11 is provided.
It is fixed between the heating resistor 6 and the protective film 13.

A step 16 made of glass or the like is provided between the regulating body 15 and the heating resistor 6.
The step 16 extends in the width direction of the thermal transfer ribbon 3 and is substantially equal to or longer than the width H1 of the thermal transfer ribbon 3, as shown in FIGS. When a printing operation is performed while pressing the thermal transfer ribbon 3 and the print-receiving medium 9 against the surface of the platen 4 by the heating resistor 6 in 1, at least on the running upstream side of the thermal transfer ribbon 3 from the location of the heating resistor 6. The entirety of the thermal transfer ribbon 3 in the width direction is sandwiched between the surface of the platen 4 and the entire thermal transfer ribbon 3 is pressed against the surface of the platen 4 (see FIG. 4).

With such a configuration, an appropriate portion in the longitudinal direction of the heating resistor 6 is heated according to the printing pattern, and the ink is melted from the thermal transfer ribbon 3 that travels while pressing while pressing the surface of the printing medium 9. Transfer to When the ink is solidified, the thermal transfer ribbon 3 and the print-receiving medium 9 are temporarily bonded at the printing location, but on the downstream side of the travel of the thermal transfer ribbon 3 and the print-receiving medium 9, the thermal transfer ribbon 3 The thermal transfer ribbon 3 is peeled from the surface of the print-receiving medium 9 on the downstream side of the printing location since the print is moved in a bent direction.

At this time, for example, when printing is performed using one half in the width direction of the thermal transfer ribbon 3 stored in the ribbon cassette 2, or printing can be performed on the entire width of the thermal transfer ribbon while the thermal transfer ribbon is running. In the case where printing is performed only at a position deviated in one of the width directions of the thermal transfer ribbon 3 as in the case where the ribbon 3 is deviated to one side of the width of the ribbon 3, the solidified portion of the ink and the travel of the thermal transfer ribbon 3 The peeling force acting upon the peeling between the downstream side (the projecting portion 14 side and the take-up reel 28 side of the thermal transfer ribbon 3) differs in magnitude in the width direction of the thermal transfer ribbon 3. In other words, although the ink temporarily melts and solidifies, the peeling force on the side where the thermal transfer ribbon 3 and the print-receiving medium 9 are temporarily bonded is large, but the unprinted portion is peeled off because there is no temporary adhesion by the ink. Since almost no force is required and the peeling force becomes unbalanced in the width direction of the thermal transfer ribbon 3, a force to move the moving thermal transfer ribbon 3 in the width direction acts on the running thermal transfer ribbon 3, and if the step 16 If the pressing force is not applied, there is a problem that the thermal transfer ribbon 3 moves in the width direction and meanders, wrinkles are generated on the thermal transfer ribbon 3, and printing defects such as blurred printing occur.

As in the present invention, the thermal transfer ribbon 3 and the print-receiving medium 9 are sandwiched between the step 16 and the platen 4 by the heating resistor 6 at an upstream side of a printing position where the heat transfer ribbon 3 is pressed against the platen 4. The step 16 uniformly presses the thermal transfer ribbon 3 against the surface of the platen 4 over the entire width direction, thereby controlling the movement of the thermal transfer ribbon 3 due to the imbalance of the peeling force.

Therefore, even if uneven peeling force acts on the downstream side of the step portion 16 in the traveling direction, the traveling thermal transfer ribbon 3 does not meander, and the thermal transfer ribbon 3 does not wrinkle, and the print fading does not occur. No printing failures such as occur.
In this case, if the material of the platen 4 is made of an elastically deformable material such as a hard rubber, the thermal transfer ribbon 3 can be pressed over a wide range of the surface of the platen 4 by the pressing force of the step portion 16, and the platen 4 can be securely pressed. The movement of the thermal transfer ribbon 3 in the width direction can be restricted, and the meandering and wrinkling of the thermal transfer ribbon can be more effectively prevented.

In the second embodiment shown in FIG. 5, a substantially flat step 16 is formed continuously following the raised portion 12 on which the heating resistor 6 is formed. And at least the entire width of the thermal transfer ribbon 3 in the width direction of the thermal transfer ribbon 3 is pressed against the surface of the platen 4 on the upstream side of the position.

In other words, the heating resistor 6 is formed on one side of the step portion 16. In this case, a part of the vitreous protective film for protecting the surface including the heating resistor 6 may be formed so as to also serve as the step portion.

In the embodiment shown in FIG. 6, the cross-sectional shape of the step portion 16 includes the location where the heating resistor 6 is arranged, and is located on the upstream side of the location of the heating resistor 6 in the traveling direction of the thermal transfer ribbon 3.
The thermal transfer ribbon 3 is formed in a convexly curved shape so as to press at least the entire width direction of the thermal transfer ribbon 3 against the surface of the platen 4.

In any of the above cases, if the platen 4 is made of an elastically deformable material such as hard rubber in the same manner as described above, the surface of the platen 4 can be widened by the pressing force of the step 16. This is preferable because the thermal transfer ribbon 3 can be pressed over the entire area.

In each of the embodiments shown in FIGS. 7 to 9, the platen 40 has a circular cross section. In FIG. 7, the platen 40 is slightly moved from the raised portion 12 on which the heating resistor 6 is formed to the upstream side of the travel of the thermal transfer ribbon 3. A step 16 is provided at a remote position. FIG.
In the embodiment shown in FIG. 5, the embodiment is the same as the embodiment shown in FIG. The embodiment of FIG. 9 is similar to the embodiment of FIG.

As described above, if the platen 40 in these cases is made of an elastically deformable material such as hard rubber, the pressing force of the step 16 covers a wide area of the surface of the platen 4. This is preferable because the thermal transfer ribbon 3 can be pressed.

In each of the above embodiments, the step 16
Is formed to be substantially equal to or longer than the width dimension of the thermal transfer ribbon 3, but may be formed to be substantially equal to or longer than the maximum printing width by the heating resistor 6. In this case, the portion that is sandwiched between the step 16 and the surface of the platen 4 and pressed against the surface of the platen 4 is a portion corresponding to the maximum printing width in the width direction of the thermal transfer ribbon 3.

Further, in each of the above embodiments, the thermal transfer ribbon 3 is sandwiched between the step 16 and the surface of the platen 4 and the thermal transfer ribbon 3 is pressed against the surface of the platen 4. It is important to control the movement of the thermal transfer ribbon 3 in the width direction due to the balance by sandwiching the ribbon between the step 16 and the platen 4, and it is necessary to press the surface of the platen 4 with the step 16. There is no. Therefore, the thermal transfer ribbon 3 may be simply held between the step 16 and the platen 4.

[0029]

As described above, the thermal head according to the first aspect of the present invention extends in the width direction of the movable thermal transfer ribbon, and moves the thermal transfer ribbon and the printing medium toward the platen. An elongated heating resistor arranged on a substrate so as to be able to be pressed together, and the thermal transfer ribbon and the print-receiving medium are sandwiched between the heating resistor on the substrate and the surface of the platen on the upstream side in the traveling direction of the thermal transfer ribbon. A step that extends at least in the width direction of the thermal transfer ribbon, and is substantially equal to the maximum printing width by the heating resistor,
It is formed longer.

With this configuration, the thermal transfer ribbon is formed by the heating resistor in the width direction of the thermal transfer ribbon and the print-receiving medium in the width direction on the upstream side of the printing position where the printing medium is pressed against the platen by the heating resistor. By uniformly sandwiching the entire printing area corresponding to the maximum printing width with the surface of the platen, it is possible to regulate the movement of the thermal transfer ribbon in the width direction due to the imbalance of the peeling force, and the traveling downstream side therefrom. Therefore, even if a non-uniform peeling force is applied, the running thermal transfer ribbon does not meander, wrinkles do not occur on the thermal transfer ribbon, and printing defects such as print fading do not occur.

[0031] The invention described in claim 2 is the same as that in claim 1.
Wherein a heating resistor is provided on one side of the step portion.

According to this structure, in addition to the effect of the first aspect of the present invention, the location where the heating resistor is arranged and the step are integrated, and the effect that the pressing area of the thermal transfer ribbon against the platen can be increased. Play.

According to a third aspect of the present invention, in the thermal head according to the second aspect, the step portion is formed to have a convexly curved cross section including the location of the heating resistor. In addition to the effects of the invention described in claim 1 and claim 2, the action of pressing against the platen on the upstream side of the thermal transfer ribbon traveling from the location of the heating resistor near the uppermost surface portion having the convexly curved cross section. This makes it easier to execute.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a main part of a thermal transfer printing apparatus.

FIG. 2 is a perspective view of a main part of the thermal head.

FIG. 3 is an enlarged plan view of a main part of the thermal head.

FIG. 4 is a main part enlarged side view showing the first embodiment of the step portion.

FIG. 5 is an enlarged side view of a main part showing a second embodiment of the step portion.

FIG. 6 is an enlarged side view of a main part showing a third embodiment of a step portion.

FIG. 7 is an enlarged side view of a main part showing a fourth embodiment of a step portion.

FIG. 8 is a main part enlarged side view showing a fifth embodiment of a step portion.

FIG. 9 is a main part enlarged side view showing a sixth embodiment of a step portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermal head 3 Thermal transfer ribbon 4 Platen 6 Heating resistor 7 Substrate 9 Media to be printed 12 Raised portion 15 Restriction portion 16 Step portion

Claims (3)

[Claims] An elongated heating resistor extending in a width direction of a movable thermal transfer ribbon and disposed on a substrate so as to be able to press the thermal transfer ribbon and a print-receiving medium together toward a platen; A step portion for sandwiching the thermal transfer ribbon and the print-receiving medium with the surface of a platen on the upstream side of the thermal transfer ribbon in the traveling direction of the thermal transfer ribbon, wherein the step portion is at least in the width direction of the thermal transfer ribbon. A thermal head, wherein the thermal head is formed to be substantially equal to or longer than the maximum printing width of the heating resistor. 2. The thermal head according to claim 1, wherein a heating resistor is provided on one side of the step portion. 3. The thermal head according to claim 2, wherein the step portion is formed to have a convexly curved cross section including the location of the heating resistor.