JPH0749538A - Original lighting device - Google Patents

Abstract

PURPOSE:To sufficiently lower the ambient temperature of a temperature detection means and to guarantee high safety against a fault or the like by providing a heat radiation means for cooling the temperature detection means and arranging it in a draft air duct by a ventilation means. CONSTITUTION:One part of a cooling wind by a cooling fan 27 is deflected in the direction of an original platen glass 31 by a deflecting plate 28A and passed through a gap between the glass 31 and a cover 28. Then, it flows in the direction of a lighting system 21. Besides, one part of the cooling wind which is not deflected by the plate 28A is passed through a gap between the cover 28 and the housing 1A of a main scanning table and it flows in the direction of the lighting system 21. The glass 21 and the lighting system 21 heated by a lamp at a reading time are cooled by the cooling wind. Since a heat radiating fin 21A provided near a thermoswitch 22 is positioned in the cooling wind, the heat radiating effect thereof is specially high and the set temperature for detecting the temperature of the thermoswitch 22 can be set to be sufficiently low. That means, the high safety is guaranteed against the fault.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document illuminating device such as a copying machine or an image reader.

[0002]

2. Description of the Related Art Conventionally, in a copying machine or the like, a cooling fan is provided in the main body of the apparatus or in the vicinity of the illumination unit in order to cool the illumination unit that illuminates the original. Furthermore, if the lamp continues to light due to a failure of the lamp power supply for lighting the lamp of the lighting unit or its control means, or if the cooling fan fails, temperature detection of a temperature fuse, thermoswitch, etc. is taken as a safety measure. The means is provided near the lamp of the lighting unit.

[0003]

By the way, the temperature detecting means does not operate when the apparatus is operating normally, but operates promptly when the fan for cooling the lighting section fails, and the like. It is required to prevent the document table in the vicinity thereof from getting hot and prevent accidents such as glass breaking.

For this purpose, it is necessary to sufficiently lower the ambient temperature of the temperature detecting means during normal operation, but in the conventional device, this point is insufficient and it is said that the device has sufficient safety. It was something I couldn't say.

[0005]

According to the present invention for solving the above-mentioned problems, there is provided an illumination unit having a light source for illuminating an original, an air-blowing means for cooling the illumination unit, and turning on / off of the light source. In a document illuminating device having a temperature detecting means for detecting the temperature around the lighting unit for controlling lighting, a heat radiating means for cooling the temperature detecting means is provided, and the heat radiating means blows air by the air blowing means. It is characterized by being placed on the road.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a document reading device equipped with a document illuminating device according to an embodiment of the present invention. Where 1 is CC
A reading optical system including a D reading sensor 2 is mounted, and a main scanning table 4 which is driven in the main scanning rails 3A and 3B in the directions of arrows A and B to movably support the main scanning table 1. The sub-scanning base moves along the sub-scanning rails 5A and 5B. 6A and 6B are side plates provided at both ends of the sub-scanning table 4 and supporting the ends of the guide rails 3A and 3B, 2 is a main scanning drive system attached to the side plate 6B, and 8 is a main scanning table 1.
Is a wire which is stretched between the pulleys 9A and 9B and is driven by the motor 10 of the main scanning drive system 7.

A sub-scanning rail 5A for guiding the sub-scanning table 4,
Both ends of 5B are supported by a document reading device main body (not shown). Reference numeral 11 denotes a drive motor for driving the sub scanning table 4,
Reference numeral 12 is a drive shaft rotated by the motor 11, 13 is a pulley provided at the end of the drive shaft, 14 is a drive belt stretched between the pulley 11A of the motor 11 and the pulley 13, and 15A and 15B are subordinates. A wire driven by the motor 11 via the drive shaft 12 is sealed at both ends of the scanning table 4, 16A is a deflection pulley for the wire 15A, and a deflection pulley (not shown) is similarly provided for the wire 15B. It is provided.

In the document reading apparatus having the above-mentioned structure,
While the main scanning table 1 is moving in the main scanning direction indicated by the arrow A, the reading sensor 2 reads from a document placed on a document table (not shown). At this time, the main scanning table 1 moves in the direction of arrow B every time the main scanning is performed, so that the home position (H
At the same time, the sub-scanning table driving motor 11 moves the sub-scanning table 4 in the direction of arrow C by a distance corresponding to the reading width. Here, the arrow D indicates the direction in which the sub-scan table 4 is returned when the reading of one document is completed.

Next, the main scanning table 1 will be described with reference to FIG. Reference numeral 21 denotes an illumination system including a lamp, a mirror, etc. for illuminating the original, and 22 is a thermoswitch which is fixed to the illumination system 21 and is a temperature detecting means for detecting the temperature of the illumination system 21 and its surroundings. A heat radiation fin 21A, which is a heat radiation means for cooling the thermoswitch, is integrally provided in the illumination system 21.

A projection lens 23 projects the original image illuminated by the illumination system 21 onto the CCD sensor 2. The original image projected by the projection lens is sequentially converted into an electric signal by the CCD sensor 2. Reference numeral 24 is a shield case for covering a driver substrate (not shown) for driving the CCD sensor, 25 is a detection piece for HP detection punched from the main scanning table housing 1A, and 26 is HP detection provided on the sub scanning table. Is a photo interrupter for detecting the HP in the main scanning direction. 27 is a cooling fan for the illumination system 21, 28 is a deflection plate 28A for deflecting the cooling air from the fan 27 toward the illumination system 21 and the platen glass.
Which are fixed to the main scanning stand housing 1A together with the fan 27.

FIG. 3 is a diagram showing the flow of cooling air to the illumination system 21. The cooling air from the cooling fan 27 is the above-mentioned deflecting plate 2.
By 8A, a part thereof is deflected in the direction of the platen glass 31, passes through the gap between the platen glass 31 and the cover 28, and flows toward the illumination system 21. Further, a part of the cooling air that is not deflected by the deflecting plate 28A passes through the gap between the cover 28 and the main scanning stand housing 1A and flows toward the illumination system 21. The platen glass 31 and the illumination system 21 heated by the lamp during reading are cooled by this cooling air. The radiating fins 21A provided near the thermoswitch 22 are located in this cooling air and have a particularly high heat radiating effect, and the temperature detection set temperature of the thermoswitch 22 can be set sufficiently low. That is, this can ensure a high level of safety in the event of a failure.

Further, a part of the cooling air of the cooling fan 27 is
The CCD flowing inside the main scanning table housing 1A and located inside the shield case 24 or the driver for driving the CCD sensor is also cooled.

FIG. 4 is a circuit diagram showing the electrical connection of the lamp 32 and the thermoswitch 22. As shown in the figure, the lamp 32 and the thermoswitch 22 are connected in series. As described above, since the cooling air from the cooling fan 27 cools the radiating fins 21A near the illumination system 21 and the thermoswitch 22, if the cooling fan 27 stops due to a failure of the cooling fan 27 or the like, the thermoswitch 2 immediately.
It is possible to prevent an accident due to the temperature rise and the like due to disconnection of the lamp 2 and the lamp 32.

[0015]

As described above, according to the present invention, it is possible to sufficiently lower the ambient temperature of the temperature detecting means, and it is possible to ensure high safety in the event of a failure.

[Brief description of drawings]

FIG. 1 is a perspective view of a document reading device to which a document illumination device according to an embodiment of the present invention is applied.

FIG. 2 is a perspective view of the main scanning table shown in FIG.

FIG. 3 is a side view showing the flow of cooling air on the main scanning table of FIG.

FIG. 4 is a circuit diagram showing electrical connection of a lamp and a thermoswitch.

[Explanation of symbols]

 1 Main Scanning Table 2 CCD Sensor 21 Illumination System 21A Radiating Fin 22 Thermo Switch 27 Cooling Fan

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G03G 15/043

Claims (1)

[Claims] 1. A lighting unit having a light source for illuminating a document, and a blowing unit for cooling the lighting unit,
A document illuminating device having a temperature detecting means for detecting a temperature around the lighting unit for controlling lighting and non-lighting of the light source, and a heat radiating means for cooling the temperature detecting means. Is a document illuminating device which is arranged in the air passage by the air blowing means.