JPH085198B2 - Thermal head unit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head unit for heating a thermosensitive recording paper, a heat fusible carbon film or the like to record characters or images.

[0002]

2. Description of the Related Art As a recording system in a recording unit of a facsimile machine or various printers, there is a thermal recording system in which a thermal recording paper, a heat-meltable carbon film or the like is heated by a thermal head to record characters or images.

FIG. 4 shows a conventional example of a thermal head unit used in such an apparatus. A thermal head substrate 2 having a heat generating portion 2a on a heat dissipation base 1 is shown.
Then, the flexible printed circuit board 3 and the head cover 4 are arranged in this order, and the head cover 4 is screwed to the heat dissipating base 1 to fix the respective parts.

The rear part of the flexible printed circuit board 3 is
The flexible printed circuit board 3 is connected to the connector 6 attached to the end of the signal cable 5, and the front part of the flexible printed circuit board 3 contacts the thermal head substrate 2 to connect the signal cable 5 and the thermal head substrate 2.

When fixing such a thermal head unit to the device, the L-shaped metal fittings 7,
8 is fixed by screwing or the like, holes 7a and 8b are formed in the L-shaped metal fittings 7 and 8, and pins 9 and 10 formed on the apparatus frame side are fitted into the holes 7a and 8b, and the thermal The head unit was rotatably supported.

Further, L-shaped metal fittings 11 and 12 are fixed to the side of the heat-generating portion 2a of the heat dissipation base 1, and cutouts 11a and 12a are formed in the L-shaped metal fittings 11 and 12, and the cutouts 11a and 12a are formed. The shaft 12 of the platen roller 13 for conveying the recording paper is engaged with the shaft 12a.

On the other hand, when recording an image, a recording sheet (not shown) is conveyed by the platen roller 13 onto the heat generating portion 2a. At this time, the heat generating portion 2a is pressed against the recording paper, whereby the recording paper is heated and an image is recorded. Further, when the heat dissipating base 1 is rotated about the pins 9 and 10 as a starting point due to this pressure contact, the L-shaped metal fittings 11 and 12 and the shaft 14 are engaged with each other so that the shift of the recording position is prevented. Become.

[0008]

By the way, conventionally, as the material of the heat dissipation base 1, aluminum, iron, stainless steel or the like has been used, and it has generally been formed by extrusion. In this extrusion process, since it is not possible to form a fine portion, the L-shaped metal fittings 7, 8, 11, 12 had to be fixed by screwing after the heat dissipation base 1 was formed.

Therefore, the conventional thermal head unit has a problem that the number of parts is large and the number of assembling steps is long.

In order to provide the heat dissipation base 1 with sufficient mechanical strength and heat dissipation effect, for example, the thickness is 6
The weight of the heat dissipation base 1 itself is 40 mm.
There is a problem in that the thermal head unit becomes large and heavy because the weight becomes 0 to 800 grams.

In view of the above problems, it is an object of the present invention to provide a thermal head unit having a small number of parts, a reduced number of assembling steps, and a small size and a light weight.

[0012]

According to the present invention, in a thermal head unit in which a thermal head substrate having a heat generating portion and a signal input terminal is fixed on a thermal radiation base, the thermal radiation base consisting of one sheet metal and the thermal radiation base. A part of both short sides of the heat-dissipating base, and a positioning means for engaging the engaged member to position the heat generating part and the platen roller; A printed circuit board having a bent portion formed by bending, a connection terminal fixed on the heat dissipation base and joined to the signal input terminal, and a portion near the joint portion of the signal input terminal and the connection terminal. And a bent portion formed by bending the heat dissipation base.

Further, in a thermal head unit in which a thermal head substrate having a heat generating portion and a signal input terminal is fixed on a radiating base, the radiating base made of one sheet metal and both short sides of the radiating base are bent. Positioning means that is formed by processing and positions the platen roller by engaging with the shaft of the platen roller, a bent portion formed by bending one side of the heat dissipation base on the long side, and the heat dissipation A printed board having a connection terminal fixed on the base and joined to the signal input terminal, and a bent portion formed by bending the heat dissipation base in the vicinity of a joint portion between the signal input terminal and the connection terminal. It is equipped with. Further, the positioning means is processed on both sides of the heat radiating base on the shorter side and on the fixed side of the thermal head substrate. Further, the bent portion is one side on the long side of the heat dissipation base and is processed on the fixed side of the thermal head substrate. Further, when the thermal head substrate is fixed, a protrusion that engages with the thermal head substrate and guides the fixing position is integrally formed on the heat dissipation base.

[0014]

The heat dissipation base is made of sheet metal, and the support mechanism for the device frame and the displacement prevention mechanism are integrally formed. The thermal head substrate and the flexible printed circuit board are fixed directly to the heat dissipation base without using a head cover. Since the thermal unit has a small number of parts, the number of materials and assembling steps are reduced, and the thermal unit is small and lightweight. Further, in this case, a bent portion for reinforcement is formed on the metal plate of the heat dissipation base, and the bent portion formed on the heat dissipation base in order to make the heights of the signal input terminal and the connection terminal coincide with each other. Therefore, the thermal unit has sufficient strength against bending.

[0015]

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

FIG. 1 is a perspective view of a thermal head unit according to an embodiment of the present invention. In the figure, the heat dissipation base 15 is formed of a sheet metal having a thickness of about 0.8 to 1.2 mm, and one side edge of the long side is bent to increase the strength against bending in the long side direction. Folding part 15a
And the central portion is bent to form the step 15b.

Further, a cut-and-raised portion 15d having a hole 15c and a cut-and-raised portion 15f having a notched portion 15e are formed at one side edge portion on the short side, and the other edge portion is provided. Is hole 1
A cut-and-raised portion 15h in which 5g is bored and a cut-and-raised portion 15j in which a cutout portion 15i is formed are formed.

A step 15b is formed on the heat dissipation base 15, and the pins 15k to 15n in which the thermal head substrate 2 is set up on the heat dissipation base 15 at a high position on the upper surface thereof.
And is fixed by adhesion or the like.
Further, the flexible printed circuit board 3 is similarly fixed to the lower position of the upper surface via a bake plate 16 for insulation. In this embodiment, the thickness of the thermal head substrate 2 is about 0.6 mm, the total thickness of the flexible printed circuit board 3 and the bake plate 16 is about 1 mm, and the step 15b is about 0.4 mm. As a result, the thermal head substrate 2
And the upper surfaces of the flexible printed circuit boards 3 are formed to have the same height.

A heating portion 2a corresponding to an image recording line is formed on one side of the upper surface of the thermal head substrate 2, and a terminal portion 2b for inputting a signal is formed on the other end. . Although not shown, the thermal head substrate 2 contains an integrated circuit for controlling the heat generating portion 2a.

A terminal portion 3a for connecting to the terminal portion 2b is formed at one end of the flexible printed circuit board 3, and a terminal portion 3b for connecting to the connector 6 is formed at the other end. . The terminal portion 3a and the terminal portion 2b are located at the same height by the step 15b, and both are connected by soldering.

The thermal head unit according to the present embodiment having the above-described structure is attached to the recording section of a facsimile machine or the like. In that case, the heat dissipation base 15 includes
By fitting pins 9 and 10 formed on the device frame side (not shown) into the holes 15c and 15g of 15h, the pins are supported rotatably on the device frame side. Also, the cut-and-raised part 1
The shafts 14 of the platen roller 13 are attached to the cutout portions 15e and 15i of the 5f and 15j so as to engage with each other. Further, a connector 6 connected to a control device (not shown) is coupled to the terminal 3b of the flexible printed board 3.

With this configuration, the recording paper (not shown) is conveyed by the platen roller 13 onto the heat generating portion 2a. At this time, the heat generating portion 2a is pressed against the recording paper, whereby the recording paper is heated and an image is recorded.

In this recording operation, when the heat dissipating base 15 rotates about the pins 9 and 10 as a fulcrum, the notch 15 is formed.
Since the shafts 14 and 15e are engaged with each other, the shift of the recording position is prevented.

Further, the temperature of the thermal head substrate 2 itself rises due to the heat generated from the heat generating portion 2a, but since the heat is radiated from the heat radiating base 15, an abnormal temperature rise is prevented.

As described above, in the present embodiment, the heat dissipation base 15 is formed of sheet metal, and the terminal portion 2b of the thermal head substrate 2 and the terminal portion 3b of the flexible printed circuit board 3 are connected by soldering to form both. The heat dissipation base 1
5 It adheres to the upper surface.

As a result, the total weight of the thermal unit is lighter than the conventional one without lowering the strength, and since the head cover 4 shown in FIG. 4 is not used, the thickness and the depth are made short. Has been done. As a result of prototyping and studying a thermal unit for recording on A4 size, the inventors have found that it can be formed with a weight of about 100 g,
It has been confirmed that the depth can be shortened by about 10 to 15 mm compared with the conventional one.

The heat dissipating base 15 has a bent portion 15a.
Since the step 15b is formed, sufficient strength against bending in the long side direction can be obtained.

Further, the cut-and-raised parts 15d and 15h for supporting the thermal head unit and the cut-and-raised parts 15f and 15j for preventing the deviation of the recording position are the heat dissipation base 15.
It is integrated with. In the case of sheet metal processing, even such a relatively complicated shape can be processed accurately and easily. As a result, the number of parts is reduced, the number of materials and the number of assembling steps are reduced, and as a result, the manufacturing cost is also reduced as compared with the conventional case where each part is configured by individual parts.

Further, since the heat dissipation base 15 is made of metal and has a shielding effect against static electricity and the like, an effect of preventing noise mixed into the integrated circuit in the thermal head substrate 2 can be obtained.

FIG. 2 is an external perspective view of a thermal head unit according to another embodiment of the present invention, and FIG. 3 is an exploded perspective view thereof. In the figure, the same reference numerals as those in FIG. 1 indicate the same parts or portions, and a head cover 4 is newly provided. The step 15b of the heat dissipation base 15 formed in FIG. 1 is eliminated.

The head cover 4 is for fixing the thermal head substrate 2 and the flexible printed circuit board 3 on the heat dissipation base 15. The head cover 4 is provided with screw holes 4a to 4d for inserting screws (not shown). As well as
A pressure contact rubber 4e is fixed along the lower surface. Further, similar to the above, the flexible printed circuit board 3 is provided with screw holes 3c to 3f, and the heat dissipation base 15 is provided with screw holes 15o to 15r for fixing the screws.

The terminal portion 3a of the flexible printed board 3 is formed on the lower surface. And the heat dissipation base 1
First, the thermal head substrate 2 is disposed on the upper surface of 5,
Next, the flexible printed board 3 is arranged so that the terminal portion 3a contacts the upper surface of the heat generating portion 2a.
Further, the head cover 4 is arranged so as to press the contact surface with the pressure contact rubber 4e, and these are fixed to the heat dissipation base 15 with screws.

As described above, in this embodiment, the thermal head substrate 2 and the flexible printed circuit board 3 are fixed on the heat dissipation base 15 by the head cover 4, but in this case also, the heat dissipation base 15 is fixed. Can be formed in the same manner as in the above-mentioned embodiment, so that the number of parts and the number of assembling steps can be reduced, and a small and lightweight thermal head unit can be obtained.

[0034]

As described above, according to the present invention, the heat dissipating base is formed of sheet metal, and the supporting mechanism for the apparatus frame and the position shift preventing mechanism are integrally formed to form the thermal head substrate and the flexible printed circuit board. Since I fixed it to the heat dissipation base directly without using the head cover,
The thermal unit has a small number of parts, reduces the number of materials and assembling steps, and is small and lightweight. Further, in this case, a bent portion for reinforcement is formed on the metal plate of the heat dissipation base, and the bent portion formed on the heat dissipation base in order to make the heights of the signal input terminal and the connection terminal coincide with each other. Therefore, the thermal unit has sufficient strength against bending.

[Brief description of drawings]

FIG. 1 is an external perspective view of a thermal head unit according to an embodiment of the present invention.

FIG. 2 is an external perspective view of a thermal head unit according to another embodiment of the present invention.

FIG. 3 is an exploded perspective view of the thermal head unit.

FIG. 4 is an external perspective view showing an example of a conventional thermal head unit.

[Explanation of symbols]

 1,15 Heat dissipation base 2 Thermal head substrate 2a Heat generating parts 2b, 3a, 3b Terminal part 3 Flexible printed circuit board 4 Head cover 4e Pressure contact rubber 6 Connector 7,8,11,12 L-shaped metal fitting 7a, 8a, 15c, 15g Hole 9, 10, 15k, 151, 15m, 15n Pins 11a, 12a, 15e, 15i Cutout 13 Platen roller 14 Shaft 15a Bent 15b Step 15d, 15f, 15h, 15j Cut-up

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location B41J 25/28 Z

Claims (5)

[Claims] 1. A thermal head unit in which a thermal head substrate having a heat generating portion and a signal input terminal is fixed on a radiating base, wherein the radiating base is made of one sheet metal, and a part of both short sides of the radiating base. A positioning means for engaging the engaged member to position the heat generating part and the platen roller, and a fold formed by bending one long side of the heat dissipation base. A printed circuit board having a bent portion, a connection terminal fixed on the heat dissipation base and joined to the signal input terminal, and bending the heat dissipation base in the vicinity of a joint portion between the signal input terminal and the connection terminal. A thermal head unit comprising a formed bent portion. 2. A thermal head unit in which a thermal head substrate having a heat generating portion and a signal input terminal is fixed on a heat dissipation base, wherein the heat dissipation base is made of one sheet metal and both sides of the heat dissipation base on the short side are bent. Formed by processing,
Positioning means for engaging the shaft of the platen roller to position the platen roller, a bent portion formed by bending one of the long sides of the heat dissipation base, and being fixed on the heat dissipation base, A printed circuit board having a connection terminal joined to the signal input terminal; and a bent portion formed by bending the heat dissipation base in the vicinity of a joint portion between the signal input terminal and the connection terminal. And thermal head unit. 3. The thermal head according to claim 1, wherein the positioning means is processed on both sides of the heat radiating base on the short side and on the fixed side of the thermal head substrate. unit. 4. The bent portion is formed by bending one of the two long sides of the heat dissipation base on the side to which the thermal head substrate is fixed. The thermal head unit according to claim 1 or claim 2. 5. When fixing the thermal head substrate, a protrusion that engages with the thermal head substrate and guides the fixing position is integrally formed with the heat dissipation base. The thermal head unit according to claim 2.