JPH0830854B2 - Original illumination device - Google Patents

Description

The present invention relates to a document illuminating device applied to an electrostatic copying apparatus.

[Background of the Invention]

The original illuminating device provided so as to be horizontally movable along the lower surface of the original plate glass of the electrostatic copying apparatus is provided with a space between the original plate glass and the original plate glass for the purpose of improving illumination efficiency and for downsizing the entire electrostatic copying apparatus. It is preferable to set it as narrow as possible.

However, when the above interval is set narrowly, the platen glass is overheated due to the heat of the lamp generated during illumination, which may surprise the operator or heat may be trapped on the lower surface of the platen glass. There has been a problem that the main reflecting mirror is deformed and the irradiation site is displaced, resulting in insufficient light quantity.

[Object of the Invention]

The present invention has been made in view of the above points, and provides a document illuminating device capable of reliably preventing an adverse effect due to the heat of a lamp even when the distance between the platen glass and the lamp is set to be extremely narrow. Is intended.

[Structure of Invention]

To achieve the above object, the present invention directs a lamp and light from the lamp to a document on the platen glass in a housing that moves in parallel along the lower surface of a platen glass on which a document is placed. In a document illuminating device having a main reflecting mirror that reflects light, an inner reflecting mirror that reflects the light of the lamp downward is provided in an upper portion of the housing so as to have a space between the upper surface plate of the housing. At the same time, a ventilation hole for creating an air flow in the space is provided in the housing to block the heat of the lamp, and the surroundings of the main reflector are automatically cooled by the air flow generated when the housing is moved or the air flow generated by the exhaust fan. It is configured to be possible.

〔Example〕

Next, the present invention will be described based on an embodiment shown in the accompanying drawings.

In the figure, 1 is a platen glass and 2 is a document illuminating device. The original illuminating device 2 is a lamp 4 installed in a housing 3 which can reciprocate in the arrow direction along the lower surface of the original glass 1.
And the main reflecting mirror 5 that covers the back of the document in a U shape, illuminates the document 6 placed on the document table glass 1 with irradiation light R ₁ at a constant angle, and reflects light R ′ from the document surface. The slit 7 provided on the bottom surface 3a of the housing 3 so as to face the illuminated portion P
Through the slit 7, bent by the first mirror 8 mounted directly below the slit 7, and transmitted to the second mirror (not shown).

Reference numeral 9 denotes an auxiliary reflecting mirror installed on the housing 3 facing the main reflecting mirror 5 with the slit 7 interposed therebetween, and the auxiliary reflecting mirror 9 is an illuminated portion of the irradiation light R ₁ from the lamp 4 and the main reflecting mirror 5. To give P a certain angle of irradiation light R ₂ from the rear,
In particular, it is effective to prevent a shadow from being formed on the step of the pasting of the pasted original.

Reference numeral 10 denotes an inner reflecting mirror horizontally provided so as to be in contact with the upper end of the main reflecting mirror 5. The inner reflecting mirror 10 forms a space 11 between the inner reflecting mirror 10 and the housing upper surface plate 3b. By reflecting the heat downward, the heat insulating effect on the platen glass 1 is enhanced. Reference numeral 12 denotes a ventilation hole provided in a front wall plate (corresponding to the back surface of the main reflecting mirror 5) 3c of the housing 3
Reference numeral 12 denotes an inner surface reflection mirror which takes in an airflow (arrow a) generated when the housing 3 moves to the right (scanning direction) or an airflow (arrow a) generated by the operation of an exhaust fan (not shown) into the housing 3. A space 11 between the housing 10 and the housing upper surface plate 3b is passed through as shown by a chain double-dashed line so that the main reflecting mirror 5 and its peripheral parts can be automatically cooled.

Reference numeral 13 denotes a light amount adjusting plate slidably provided on the upper surface of the inner reflecting mirror 4, and the light amount adjusting plate 13 illuminates the original 6 placed on the original platen glass 1 by the lamp 4 and the main reflecting mirror 5. This is for increasing or decreasing the light quantity of the irradiation light R ₁ .

In the above embodiment, the document placed on the platen glass is the irradiation light R _{1 using} the lamp 4 and the main reflecting mirror 5 as the light source,
It is illuminated from the front and back by the irradiation light R ₂ that has passed through the auxiliary reflecting mirror 9 so that a shadow will not be formed even on a bonded original.

Further, heat and stray light emitted from the lamp 4 and directed to the platen glass 1 are reflected by the inner reflecting mirror 10 to heat the inner reflecting mirror 10, and the space 11 between the reflecting mirror 10 and the housing upper surface plate 3b. Since an air layer is formed, it becomes difficult for the heat of the inner reflecting mirror 10 itself to be transferred to the top plate of the housing and the platen glass 1. Moreover, since an airflow taken from the ventilation light 12 provided on the front wall surface of the housing 3 while the housing 3 is moving can be generated in the space 11, the inner reflecting mirror 10 and the housing top plate 3b are automatically cooled.

〔The invention's effect〕

As described above, according to the present invention, the lamp and the light from the lamp are directed to the original on the original table glass in the housing that moves in parallel along the lower surface of the original table glass on which the original is placed. In an original illuminating device having a main reflecting mirror for reflecting, an inner reflecting mirror for reflecting the light of the lamp downward is provided in an upper part of the housing so as to have a space between the upper plate and the upper plate of the housing. Since the housing is provided with a vent hole for creating an air flow in the space, extra light and heat from the lamp and the main reflecting mirror are not transmitted to the platen glass. Therefore, unnecessary heating of the platen glass can be prevented, and the lamp can be brought as close as possible to the glass.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 is a sectional view, and FIG.
The figure is a schematic external perspective view. 1 ... original glass 2 ... original lighting device 3 ... housing 4 ... lamp 5 ... main reflecting mirror 6 ... original 7 ... slit 8 ... first mirror 9 ... auxiliary reflecting mirror 10 ... Inner reflector 11 …… Space 12 …… Vent hole

Claims (3)

[Claims] 1. A main reflecting mirror for reflecting a lamp and light from the lamp toward a document on the platen glass in a housing that moves in parallel along a lower surface of a platen glass on which a document is placed. In the original illuminating device having the above, an inner reflecting mirror that reflects the light of the lamp downward in the upper part of the housing is provided so as to have a space between the upper surface plate of the housing and an air flow in the space. A document feeder, wherein a ventilation hole for making a sheet is provided in the housing. 2. The document illuminating apparatus according to claim 1, wherein the inner reflecting mirror also serves as a light amount adjusting plate. 3. An auxiliary reflecting mirror is provided at a position in the housing facing the main reflecting mirror with a slit provided in a lower surface plate of the housing sandwiched therebetween. The document illuminating device according to item 2.