JPH0448628B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal head structure in a thermal recording device such as a facsimile machine or a printer.

2. Description of the Related Art In thermal recording devices such as facsimiles and printers, image information is recorded on the thermal recording device using a thermal head that selectively generates heat according to image information.

[Prior Art] FIGS. 1 and 2 show an example of such a conventional heat-sensitive recording device. This apparatus uses a supply roll 2 formed by winding a long length of thermal recording paper 1. The thermal recording paper 1 fed out from the supply roll 2 passes through a guide roller 3 and enters between a thermal head 4 and a back roller 5. The thermal head 4 is rotatable around its lower end, and its printing portion 7 is pressed against the back roller 5 by the force of a spring 6. When the motor 8 is driven, its driving force is transmitted to the bag roller 5 via the belt 9 and the like, and the roller 5 is rotated in the direction of the arrow. When the back roller 5 rotates in the direction of the arrow, the thermal recording paper 1 is run in the direction of the arrow. At this time, the thermal head 4 is driven, and its printing section 7 selectively generates heat in accordance with the image information. As a result, image information is recorded on the thermal recording paper 1. The thermal recording paper 1 after recording is sent to a rotary cutter 11 via a guide plate 10, cut into a predetermined length, and discharged to a discharge tray (not shown).

In such a device, if the stop mode is set after cutting the thermal recording paper 1, the thermal recording paper 1 present between the printing section 7 of the thermal head 4 and the rotary cutter 11 will be cut off when the next recording is performed. It ends up being wasted. Therefore, in such a device,
After the last cut of the thermal recording paper 1 is completed, the motor 8 is reversed, the back roller 5 is reversed, and the thermal recording paper 1 is moved backward by a certain amount. That is, the leading edge of the thermal recording paper 1 is returned to a position slightly ahead of the printing section 7 of the thermal head 4, and in this state, the stop mode is set.

Incidentally, in such a device, electrical components such as ICs (not shown) and a cover 12 for protecting these are provided on the upper surface of the thermal head 4. The cover 12 is made of a plastic plate or sheet metal with a thickness of about 1 to 2 mm, and the cover 12 is made of a plastic plate or sheet metal with a thickness of about 1 to 2 mm.
It is attached to the thermal head 4. However, in such a device, the thickness of the thermal recording paper 1 is
70 μm, whereas the cover 12 has a relatively thick thickness of about 1 to 2 mm. As a result, a relatively large gap is formed. Therefore, in such a device, when the conveyance of the thermal recording paper 1 is resumed, the leading edge of the thermal recording paper 1 is connected to the leading edge 1 of one cover 12.
2a, causing paper jams. Therefore, in such a device, one cover 1
Plastic is poured into the gap formed by the tip 12a of 2, or an adhesive tape is attached to this part, thereby removing the gap. However, with such a device,
It is difficult to make the amount of plastic poured or the adhesive tape applied uniformly over the entire surface, and these may come off over time. Therefore, such devices have the drawbacks of non-uniform quality and poor reliability.

[Object of the Invention] The present invention was made in view of the above circumstances, and an object of the present invention is to provide a thermal head structure that can effectively prevent paper jams over a long period of time.

[Means for Achieving the Object] In the present invention, a sheet-like elastic member is provided in a cantilevered manner at the tip facing the printed part of the thermal head of a cover that protects electrical components such as an IC, and the free end of the sheet-like elastic member is provided with a thermal head. Place it close to the top of the head. This eliminates the gap formed between the tip of the cover and the top surface of the thermal head, thereby achieving the above-mentioned purpose.

The present invention will be explained in detail with reference to Examples below.

[Embodiment] FIGS. 3 and 4, in which the same parts as in FIGS. 1 and 2 are given the same reference numerals, show the main parts of a thermal head structure in an embodiment of the present invention. .

In this thermal head arrangement, the cover 12
The cover main body 21, the rear wall 22 provided at a substantially right angle to the rear end of the cover main body 21, and the front wall 2 provided at an appropriate inclination at the tip of the cover main body 21.
It consists of 3. The cover 12 is made of a plastic with low shrinkage such as polycarbonate,
Its thickness is approximately 1.5mm. In the front wall 23 of one cover 12, one end in the width direction of a band-shaped elastic sheet 24 made of a stainless steel plate with a thickness of about 50 μm is buried by insert molding or the like. When slits are appropriately provided in the elastic sheet 24, shrinkage during molding of one cover 12 can be absorbed by the slits, and the elastic sheet 2
The straightness of 4 can be maintained even better. When the rear end of one cover 12 is attached to the top surface of the thermal head 4 with the screws 13, the rear wall 22 is in contact with the top surface of the thermal head 4,
The front wall 23 is appropriately floating above the thermal head 4 and biased clockwise in FIG. In this state, the free end of the elastic sheet 24 is in close contact with the upper surface of the thermal head 4.

In this thermal head structure, the elastic sheet 2
Since the free end of thermal head 4 is in close contact with the upper surface of thermal head 4, no gap is formed between them. Furthermore, while the thickness of thermal recording paper is approximately 70 μm, the thickness of the elastic sheet 24 is relatively thin at approximately 50 μm.
Even if it gets caught on the free end of 4, it will easily come off. Furthermore, since the elastic sheet 24 is embedded in the front wall 23 of one cover 12, it will not come off over time. Therefore, it is possible to effectively prevent paper jams over a long period of time.

In the above embodiment, the front wall 2 of one cover 12
3, an elastic sheet 24 made of a stainless steel plate is buried therein by insert molding or the like, but the present invention is not limited thereto. For example, the elastic sheet 24
is made of a plastic plate made of polycarbonate etc. with a thickness of about 50 μm, and this is attached to one cover 1.
It may also be bonded to the outer surface of the front wall 23 of No. 2 using an adhesive or ultrasonic waves. Alternatively, one cover 12 and the elastic sheet 24 may be integrally formed of plastic such as polycarbonate.

[Effects of the Invention] As explained above, according to the present invention, since the free end of the sheet-like elastic member provided on the cover is brought into close contact with the upper surface of the thermal head, paper jams can be effectively prevented for a long period of time. This improves the reliability of paper running.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view showing an example of a conventional thermal recording device, Fig. 2 is a plan view of its thermal head structure, and Fig. 3 shows main parts of the thermal head structure in an embodiment of the present invention. The side view and FIG. 4 are plan views of the thermal head structure. 4...Thermal head, 7...Printing section, 12...
...Cover, 24...Elastic sheet.

Claims (1)

[Claims] 1. A thermal head that has a printing section that selectively generates heat according to image information, and a cover that is installed on the top surface of this thermal head after the printing section and protects electrical components such as ICs that are installed on the top surface. 1. A thermal head structure comprising: a sheet-like elastic member provided in a cantilevered manner at the tip of the cover facing the printed portion, and having a free end brought into close contact with the upper surface of the thermal head.