JP2791654B2 - Thermal print head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved support plate of a thermal print head which is used by being pressed against a platen.

[0002]

2. Description of the Related Art As a scanning head used while being pressed against a platen, a thermal print head for printing and a contact image sensor for reading are known. Among them, a thermal print head will be described as an example. The thermal print head itself is a device in which a heating resistor as a printing element is arranged in a scanning direction on a ceramic substrate. Normally, instead of applying a pressing force directly to the thermal print head itself (hereinafter referred to as a thermal print head substrate) and pressing it against the platen, the thermal print head substrate is mounted on a support plate that also functions as a heat sink. The support plate is pressed against the platen.

Conventionally, a thick aluminum substrate is generally used for the support plate.
As disclosed in Japanese Unexamined Patent Publication (Kokai) No. H11-115, recently, it has been attempted to use a sheet metal which is inexpensive and easy to process.

[0004]

However, in the support plate having the structure as disclosed in Japanese Patent Application Laid-Open No. Hei 5-229144, only one side edge in the longitudinal direction of the support plate is bent, so that the strength in the twisting direction is low. In addition to the possibility of weakly affecting print quality, the connection terminal portion 2b is disposed on the low strength side where no bent piece exists as shown in FIG. 1 of the publication, and the connection terminal portion 3a of the flexible 3 for connecting to the outside. And the support plate is electrically connected, there is a possibility that a good connection state cannot be maintained. In FIG. 1 of the publication, a step having only the thickness of the flexible substrate is provided for the purpose of arranging the thermal print head substrate 2 and the flexible substrate 3 flush with each other. Insufficient in strength. In particular, when one plate is used to integrally form the platen support means,
Since they are formed with the same thickness, the influence of transmission of vibrations and the like may be greater than in the case where conventional aluminum is used.

Accordingly, an object of the present invention is to solve the above-mentioned problem.

[0006]

In order to solve the above-mentioned problem, the invention according to claim 1 of the present application arranges a row of heating resistors along one longitudinal edge of a surface of a support plate. At the same time, a thermal print head substrate having a connection terminal portion is provided on the other edge, and the support plate is formed by bending a single sheet metal by press working, and forming a support means for supporting a platen rotating shaft at the end portion. In the thermal print head, the longitudinal edges of the support plate are bent to form bent pieces, respectively, while the width of the support plate in the short side direction is larger than the width of the thermal print head substrate. The thermal print head substrate is formed on the support plate so that the connection terminals and the rows of the heating resistors provided on the other longitudinal edge of the substrate are located between the bent pieces. Characterized in that it is arranged to.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a thermal print head of the present invention will be described with reference to the drawings. The support plate shown in FIG. 1 is applied to a thermal print head, and FIG. 1 is an exploded perspective view thereof. The support plate 2 is formed by pressing a sheet metal (made of a steel plate), and bent pieces 2a and 2b are bent downward at both longitudinal side edges in the drawing, and holes 7 and 7 are formed at the center. Is formed.

A guide 10 having a notch for receiving a rotating shaft (not shown) of the platen is provided at the end portions 2c and 2c of the support plate.
10 are integrally formed. Groove-shaped concave portions 11, 11 for reinforcing the base end portions of the guides 10, 10 are formed by squeezing. The support plate 2 has one through hole 2e (two in total) in the vicinity of each guide 10 as an index, which is a feature of the present invention, in the print scanning direction. In the present embodiment, the diameter of the through hole 2e is about 1.
0 mm. Near the center of the support plate 2, two pin holes 2d for inserting pins of a pallet are formed.

The thermal print head substrate 12 is formed by forming an electrode pattern (not shown) and a heating resistor 13 on a ceramic substrate and mounting a driving IC (not shown). These driving ICs are covered and protected by a resin mold 14. This thermal printhead substrate 1
2 is adhered on the support plate 2. The thermal print head substrate 12 is disposed so as to be located between the bent pieces 2a and 2b of the support plate 2, and has a connection terminal portion 15 described later.
Is disposed near the bent piece 2b. That is, FIG.
As shown in the figure, the width H of the support plate 2 is formed larger than the thermal print head substrate h.

A flexible substrate 17 to be described later is superimposed and electrically connected to the connection terminal portion. Therefore, even if the connection portion is slightly affected by the use state (for example, thermal influence or vibration) of the thermal print head, the connection is made. It is possible to maintain a good state. Particularly, as shown in the present embodiment, since one sheet metal is bent and the guide 10 for supporting the rotation shaft of the platen is integrally formed at the end of the support plate 2, the rotation of the rotation shaft is made of a thin sheet metal material. However, it is difficult to maintain the above-described connection state due to the vibration caused by the feeding of the object to be printed (for example, paper). However, the configuration according to the present embodiment can reduce such a fear.

On the upper surface of the printed circuit board 16, a flexible board 17 is further stacked. Flexible board 17
Of the thermal printhead substrate 12 protrudes from the printed circuit board 16 and overlaps with the connection terminal 15.
The printed circuit board 16 also has holes 19, 18, 18, 19
Is provided. Also, on the lower surface of the printed circuit board 16,
Connectors 20, 20 for external connection are attached.

On the printed circuit board 16, the holding cover 2 is provided.
1 is attached. A pressing rubber 22 extending in the print scanning direction is provided on the lower surface of the holding cover 21.
4, 23, 23 and 24 are established. In this embodiment, two screws 25, 25 are respectively inserted into holes 23, 23,
The holding cover 21 and the printed circuit board 16 are fixed by being inserted through the holes 18 and 18 and screwed into the holes 7. At this time,
The pressure contact rubber 22 presses the front edge of the flexible board 17 against the connection terminal section 15, so that the printed circuit board 16 and the thermal print head board 12 are electrically connected.

The thermal print head board 12 and the printed circuit board 16 (the flexible board 17)
), And assembly of the holding cover 21 on the support plate 2 is performed as follows. First, as shown in FIG. 3, the pins 103 on the pallet 101 on the assembling apparatus are inserted into the pin holes 2d of the support plate 2, and the support plate 2 is set on the pallet 101. Next, the head substrate 12 is placed on the support plate 2. And
Through hole 2 e of support plate 2 and heating resistor 1 of head substrate 12
While looking at each other, the head substrate 12 is positioned with respect to the support plate 2 with a certain degree of accuracy. At this time, the through hole 2e
Since the positioning is performed while recognizing only both the heating resistor 13 and the heating resistor 13, the positional accuracy is improved in each step as compared with the related art.

Thereafter, the flexible substrate 17 on the circuit board 16 is electrically connected to and fixed to the head substrate 12 while ensuring appropriate positional accuracy with respect to the pins 103. After the holding cover 21 is set at a predetermined position on the circuit board 16, the screws 25 are tightened to press the flexible board 17 onto the head board 12 with the pressing rubber 22 of the holding cover 21, and the head board is placed on the support plate 2. 12. The circuit board 16 (including the flexible board 17) and the holding cover 21 are integrally fixed.

Next, a modification will be described with reference to FIG.
This is a method in which a thermal print head substrate (FIG.
Is attached. Guides 10 and 10 are provided at both ends of the support plate 2 as support means for supporting a rotating shaft (not shown) of a platen, and near the center edge, a pin for inserting a pin on a pallet described later is inserted. Two holes 2d are formed.

As shown in FIG. 4, a thermal print head substrate 12 is fixed on the support plate 2,
Has a heating resistor 13 arranged in the print scanning direction. The head substrate 12 is electrically connected to a flexible substrate (not shown in particular) provided on the printed circuit board 16, and the flexible substrate is pressed against the head substrate 12 by a pressing rubber 22 of a pressing cover 21 attached to the circuit substrate 16 with screws 25. At the same time, the head substrate 12, the circuit substrate 16 (including the flexible substrate), and the pressing cover 21 are integrally fixed to the support plate 2. Note that a connector 20 for external connection is connected to the circuit board 16.

[0017]

According to the structure of the present invention as described above, a row of heating resistors is arranged along one longitudinal edge of the surface of the support plate, and a connection terminal portion is provided on the other edge. A thermal print head substrate is provided.
In a thermal print head in which a sheet metal is bent by press working and a supporting means for supporting a platen rotating shaft is formed at an end thereof, bending is performed on both longitudinal side edges of the support plate, and each is bent. On the other hand, the width of the support plate in the short side direction is formed to be larger than the width of the thermal print head substrate, and the row of the connection terminal portion and the row of the heating resistor provided on the other longitudinal edge of the substrate are formed. Also, since the thermal print head substrate is disposed on the support plate so as to be located between the bent pieces, the following effects can be obtained.

That is, since the width of the support plate is smaller than the width of the thermal print head substrate, the connection terminal portion is disposed between the two bent pieces. , It is possible to increase the strength for maintaining the connection state even when transmitted via the.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a thermal printhead showing a support plate and components assembled on the support plate according to an embodiment of the present invention.

FIG. 2 is an external perspective view showing a modification.

FIG. 3 is a partially omitted perspective view showing a state in which a support plate is placed on a pallet of an assembling apparatus.

FIG. 4 is a side view of a thermal print head in which components are assembled on a support plate.

[Explanation of symbols]

 2 Support Plate 2e Through Hole (Indicator) 2d Pin Hole 10 Guide 12 Thermal Print Head Board 13 Heating Resistor

Claims (1)

(57) [Claims] 1. A thermal print head substrate having a row of heating resistors arranged along one longitudinal edge of a surface of a support plate and a connecting terminal portion provided at the other edge, wherein the support plate is In a thermal print head in which one sheet metal is bent by press working and supporting means for supporting a platen rotating shaft are formed at the end thereof, bending processing is performed on both longitudinal edges of the supporting plate, and While forming the bent piece, the width of the support plate in the short side direction is formed to be larger than the width of the thermal print head substrate, and the row of the connection terminals and the heating resistor provided on the other longitudinal edge of the substrate are formed. A thermal printhead, wherein a thermal printhead substrate is disposed on a support plate such that each of the thermal printhead substrates is located between the bent pieces.