JPS59127786A - Heat-sensitive recorder - Google Patents

Abstract

PURPOSE:To prevent the surface temperature of a back roller from being abnormally raised and enhance image quality, by bringing a heat-radiating roller into rolling contact with the back roller to thereby positively remove heat from the surface of the back roller. CONSTITUTION:When the back roller 26 is rotated, the heat-radiating roller 29 is also rotated in a following-up manner, so that heat is efficiently transferred from the surface of the back roller 26 to the heat-radiating roller 29. Since both ends of the roller 29 are opened, heat is radiated also from the inner peripheral surface of the roller 29, so that a heat-radiating surface is fairly large. In addition, when a fan 32 is rotated, the inner peripheral surface of the roller 29 is positively air-cooled, so that heat is radiated more favorably.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to thermal recording devices such as facsimiles and printers.

2. Description of the Related Art In thermal recording devices such as facsimiles and printers, image information is recorded on thermal recording paper or plain paper overlaid on an ink donor sheet using a thermal head that selectively generates heat according to image information.

(Prior Art) FIG. 1 shows 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 pressed against the thermal head 4 . When the back openings 5 rotate 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 heating elements selectively generate heat according to image information. As a result, thermal recording paper 1
Image information is recorded. After recording, the thermal recording paper 1 is cut into a predetermined length by a rotary cutter 6, and is discharged to a discharge tray (not shown).

FIG. 2 shows an example of another conventional heat-sensitive recording device. In this device, a long ink donor sheet 11
A supply roll 12 is used. The ink donor sheet 11 fed out from the supply roll 12 passes sequentially between the guide roller 13 , the thermal head 14 and the back roller 15 , and between the drive roller 16 and the pinch roller 17 , and then is taken up by the take-up roll 18 . It looks like this. Plain paper 19 cut to a predetermined size is sent out from a supply tray (not shown), travels in the direction of the arrow, reaches near the thermal head 14, and then turns over.
A sensor, also not shown, detects this and rotates the drive roller 16 in the direction of the arrow. As a result, plain paper 19
passes between the thermal head 14 and the back roller 15 while being superimposed on the ink donor sheet 11, and at this time thermal transfer recording is performed by driving the thermal head 14. The plain paper 19 after recording is the ink donor sheet 11
The paper is peeled off from the paper, advances in the direction of arrow B, and is discharged to a discharge tray (not shown).

By the way, in such a conventional device, the thermal head 4
．． A part of the heat generated by driving the thermal head 4.14 is accumulated in the substrate of the thermal head 4.14 and the back roller 5.15. When the device is operated continuously, the thermal head 4
．． The surface temperatures of the substrate 14 and the back rollers 5 and 15 become abnormally high, causing blurring and fraying of recorded images, resulting in a decrease in image quality.

Therefore, in such a conventional device, the thermal head 4.
The temperature of the substrate 14 is detected by a thermistor or the like, and the voltage applied to the heating element of the thermal head 4.14 is controlled based on the detected temperature, thereby causing the temperature of the substrate of the thermal head 4.14 and the back roller 5.15 to be controlled. Reduces the amount of heat transferred.

However, since the back roller 5.15 is made of rubber with low thermal conductivity, even if the amount of heat transferred to it is reduced, its heat dissipation is poor and its surface temperature may become abnormally high. Therefore, in such an apparatus, recorded images still blur or become blurred, resulting in poor image quality.

(Object of the Invention) The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a heat-sensitive recording device that can prevent the surface temperature of the back roller from becoming abnormally high.

(Means for Achieving the Object) In the present invention, the heat dissipating roller is brought into rolling contact with the back roller to actively remove heat from the surface of the back roller, thereby achieving the above-mentioned object.

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

(Embodiment) FIG. 3 shows the main parts of a thermosensitive recording device according to an embodiment of the present invention, and FIG. 4 shows a cross section taken along line IV--IV in FIG. 3.

In this device, a thermal head 22 is mounted on a frame 21. The thermal head 22 has a ceramic substrate 24 provided on the upper surface of a metal base 23 made of aluminum or the like, and a ceramic substrate 24 at the center of the upper surface of the substrate 24. The thermal head 22 has a structure in which a heating element 25 is provided in a straight line.A back roller 26 is in pressure contact with the thermal head 22.The back roller 26 is made of silicone rubber and has a
It is rotatably attached to the frame 21 via a foot 27 and a bearing 28. A heat radiation roller 29 is in rolling contact with the back roller 26 . The heat radiation roller 29 is
It is made of a metal pipe such as aluminum and is rotatably attached to the frame 21 via a bearing 30 and an E-ring 31. A fan 32 is provided near one end of the heat radiation roller 29.

In this device, when the back roller 26 is rotated in the direction of the arrow, the heat radiation roller 29 is accordingly rotated in the direction of the arrow. Therefore, the heat radiation roller 29 does not interfere with the rotation of the back roller 26.

Further, the surfaces of the back roller 26 and the heat radiation roller 29 are in total contact with each other. Therefore, heat is efficiently transferred from the surface of the back roller 26 to the heat radiation roller 29. Since both ends of the heat dissipation roller 29 are open, heat is also dissipated from its inner peripheral surface, and the heat dissipation area is quite large. Therefore, the heat transferred from the back roller 26 to the heat radiating roller 29 can be efficiently dissipated. At this time, when the engine 32 rotates, the inner peripheral surface of the heat dissipation row 29 is actively air-cooled, and heat dissipation is performed even better. The fan 32 is
It rotates constantly during the entire process of thermal recording, or it rotates while the thermal head 22 is being driven. From the above, the surface temperature of the back roller 26 will not become abnormally high even when the devices are operated in a connected manner.

In the above embodiment, the heat dissipation roller 29 has a simple pipe shape, but the heat dissipation roller 29 is not limited to this, and for example, fins may be provided on the inner circumferential surface of the heat dissipation roller 29.

In addition, in the above embodiment, near one end of the heat dissipation roller 29) 17
32 is simply installed, but these are connected with a pipe,
The fan 32 may be stepped at a location spaced apart from the heat dissipation roller 29. Further, if heat radiation for one minute can be performed only by the heat radiation roller 29, the fan 32 may be omitted.

<Effects of the Invention> As explained above, according to the present invention, heat can be actively removed from the surface of the back roller, so even if the device is operated continuously, the surface temperature of the back roller does not become abnormally high. The image quality is improved.

[Brief explanation of drawings]

1 and 2 are schematic diagrams showing respective conventional heat-sensitive recording devices, FIG. 3 is a longitudinal sectional front view showing the main parts of a heat-sensitive recording device according to an embodiment of the present invention, and FIG. The figure is a sectional view taken along the line rv-rv in FIG. 3. 22... Thermal head 26... Back roller 29... Heat dissipation roller Application Person Fuji Xerox Co., Ltd. Representative Patent attorney Umeo Yamauchi

Claims (1)

[Claims] A linear head that selectively generates heat according to image information,
A thermal recording device characterized in that it is equipped with a back roller that presses a thermal recording paper or an ink donor sheet and a plain paper superimposed thereon on the one normal head, and a heat dissipation roller that is in rolling contact with the back roller. .