JPH0727176B2 - Original exposure method for copiers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to an original exposure method for a copying machine, and more specifically, it is applied to a copying machine in which a margin of a predetermined width is formed at the leading end of a copy. Document exposure method.

<Prior Art> Conventionally, in a copying machine, as shown in FIG. 2, a light emitting body (62) including a halogen lamp or the like is attached to a predetermined position of a main light collecting mirror (61) and a main light collecting mirror ( The sub-mirror (63) is attached so as to face the (61), and the relative mounting positions of the main condensing mirror (61) and the sub-mirror (63) with respect to the original (D) set on the contact glass (14). Therefore, it is set so that light can be emitted at incident angles opposite to each other. Then, the reflected light from the document (D) is guided vertically downward, and the slit (6
The unnecessary portion is cut by 4) and is guided to an image processing unit (not shown).

<Problems to be Solved by the Invention> In the document exposure apparatus having the above configuration, the document (D) is exposed not only by the main condensing mirror (61) but also by the sub mirror (63). Since the exposure is performed, there is an advantage that the light emitted from the light emitting body (62) can be efficiently used for exposing the original.

However, in a copying machine, a margin of a predetermined width is formed at the leading end of the copy to separate the copy paper from the photosensitive drum,
It is usual to improve the peeling performance from the fixing roller. As a specific structure for forming a blank space, a white reflection part (6) is formed on the lower surface of the contact glass (14).
Since the configuration for forming 5) is adopted, when the light emitted from the sub-mirror (63) to the document (D) is strong, the light is blocked by the reflection part (65). There is a problem in that the amount of light applied to the original document (D) is significantly different between the state in which it is not blocked by the reflecting portion (65), and the so-called copy edge is generated in the obtained copy. Further, when the light emitted from the sub-mirror (63) to the original (D) is weak, it is necessary to increase the light amount of the light emitter (62) itself in order to irradiate the original (D) with a predetermined amount of light. There is a problem that it is necessary to improve the light collection efficiency of the main light collection mirror (61).

Further, in this case, there is a limit to the improvement of the light collection efficiency, and the cost increases. Further, when the W number of the light emitting body is increased to increase the light amount, it becomes difficult to cool the glass, and the cost and the current amount increase.

<Object of Invention> The present invention has been made in view of the above problems,
It is possible to prevent the occurrence of so-called tip baldness on the obtained copy without substantially increasing the W number of the light source for exposing the original, and without particularly improving the light collection efficiency of the main light collection mirror. It is an object of the present invention to provide a document exposure method that can be performed.

<Means for Solving Problems> An original exposure method of the present invention for achieving the above object includes a main light collecting mirror, a light emitter, and a sub-mirror, and the main light collecting mirror, the light emitter, And an original exposure method in which the original set on the contact glass is irradiated with light at opposite incident angles to expose the original set while moving the sub-mirror in one direction. Until the exposure of the white reflector is completed, the output light intensity of the emitter is relatively increased by applying a relatively high voltage to the emitter, and after the exposure of the white reflector is completed. Is characterized in that the output light intensity of the light emitter is relatively reduced by applying a relatively low voltage to the light emitter.

<Operation> In the above configuration, the output light intensity of the light emitting body is relatively increased until the exposure of the white reflecting portion is completed, and after the white reflecting portion is exposed, The output light intensity is relatively reduced. The output light intensity of the light emitter does not decrease sharply even when the applied voltage is lowered. Therefore, at the leading edge of the document, the amount of light corresponding to the reflected light from the sub mirror that is blocked by the white reflecting portion can be supplemented by the irradiation light from the main condenser mirror. Therefore, the leading edge of the document can be exposed with sufficient intensity. In the exposure of the white reflecting portion, there is no particular problem even if the output light intensity is too high.

Also, since the central part and the rear end part of the document can be exposed by the irradiation light from the main focusing mirror and the sub-mirror,
Even if the output light intensity of the light emitting body is relatively low, exposure can be performed with sufficient intensity.

As described above, according to the above configuration, it is possible to perform exposure with sufficient intensity over the entire range of the document.

<Examples> Hereinafter, detailed description will be given with reference to the accompanying drawings illustrating examples.

FIG. 3 is a schematic diagram clearly showing the internal structure of the copying machine.

Reference numeral (1) is a main body of the copying machine, and the partition plate (11) divides the inside into an upper chamber (12) and a lower chamber (13).
An optical system (2) for scanning exposure of a document (D) is provided in 2), a copy processing section (4) for forming a copy image on a copy paper (P) in a lower chamber (13), and a copy. A paper transport section (8) is provided.

Here, a halogen lamp (6
2), main condensing mirror (61), and sub-mirror (6
Light source (21) composed of 3), flat reflecting mirrors (22) (23)
(24), lens (25), and plane reflecting mirror (26), and the contact glass by moving the light source (21) and the plane reflecting mirrors (22) (23) (24) in the direction indicated by arrow A. (14) The original document (D) above can be scanned and exposed. Then, the light source (21) and the flat reflecting mirror (2
2) moves integrally, the flat reflecting mirrors (23) and (24) also move integrally, and the moving speed of the former is set to be twice as high as the moving speed of the latter. , The light source (21) and the plane reflecting mirrors (22), (23) and (24) are collectively referred to as an optical section (2 ').

Further, the copy paper transport unit (8) includes a paper feed roller (8
1), a paper feed path (83), a conveyance roller (85), a registration roller (86), a heat fixing roller (88), and a discharge roller (89). The copy sheet (P) for one sheet is taken out from the cassette (16), guided to the copy processing section (4) to transfer the toner image, and the toner image is heated and fixed by the heat fixing roller (88), and then received. It is configured to discharge onto the table (18),
The present invention is not limited to this configuration, and it is possible to use a copy paper transporting unit having another conventionally known configuration, such as a configuration in which the paper feed side and the discharge side are the same side. Further, the copy processing unit (4) includes a photosensitive drum (4 which rotates in a direction indicated by C in the figure).
A charger (42), a blank lamp (B), a developing device (43), a transfer charger (44), a separating member (45), and a cleaner (46) are arranged in this order around the periphery of 1), An electrostatic latent image is formed by forming a document image on the outer surface of the photoconductor drum (41) that is uniformly charged by the charger (42), and the electrostatic charge on the peripheral portion where the electrostatic latent image is not formed is blanked. After being removed by the lamp (B), the developing device (43) visualizes the toner image, the transfer charger (44) transfers the toner image onto the copy paper (P), and the cleaner (46) collects the residual toner. However, the present invention is not limited to this configuration, and a conventionally known copy processing unit having another configuration, such as one using a belt-shaped photosensitive member, may be used.

FIG. 2 is a vertical sectional view showing an embodiment of the original exposure apparatus, which has a main condenser mirror (61), a halogen lamp (62) as a light emitting body, and a sub mirror (63).

The main condensing mirror (61) is formed into a concave mirror shape as a whole, and a halogen lamp (62) is attached to the inner rear part thereof. Then, the light X reflected by the first area (see R1 in the figure) of the main light collecting mirror (61) is directly radiated to the exposure area of the document (D) through the contact glass (14), and the main collection is performed. The light Y reflected by the second area (see R2 in the figure) of the optical mirror (61) becomes parallel to the contact glass (14) (however, in a strict sense, slightly convergent) as shown in the figure. . An inclined sub-mirror (63) is attached to the position where the light Y is irradiated, and the original (D) is exposed through the contact glass (14) while further focusing the focused light Y. The area is illuminated.

The original (D) set on the contact glass (14) can also be illuminated by direct light from the halogen lamp (62).

Further, (64) is a slit formed between the main condensing mirror (61) and the sub-mirror (63) so that the passage range of the reflected light from the document (D) can be regulated. There is.

Further, (65) is a white reflecting portion formed at a predetermined position on the lower surface of the contact glass (14) so that a margin can be formed at the leading end of the copy.

FIG. 1 is a diagram showing an electrical configuration for controlling the voltage applied to the halogen lamp (62), and is a switch for selectively outputting a different voltage with the signal from the document exposure position detecting means (66) as an input. A means (67) is provided, and the voltage output from the switching means (67) is applied to the halogen lamp (62).

More specifically, the document exposure position detecting means (66) is composed of a switch for detecting the moving position of the optical section (2 '), a pulse counter for detecting the moving time of the optical section (2'), and the like. When the end of exposure of the white reflection part (65) is detected, the original exposure position detection signal is output, and the voltage applied to the halogen lamp (62) is changed to a high voltage by the switching means (67). Can be switched to a low voltage, and the intensity of irradiation light can be reduced.

Therefore, the exposure light intensity is increased by increasing the applied voltage to the halogen lamp (62) until the exposure of the white reflecting portion (65) is completed, and the white reflecting portion (65) is increased.
By reducing the voltage applied to the halogen lamp (62) at the end of the exposure, the exposure light intensity is reduced, and the original with the optimum exposure light intensity can be exposed.

Regarding the so-called tip shadow, even if the voltage applied to the halogen lamp (62) is reduced in order to illuminate the document (D) set on the contact glass (14), the irradiation light intensity will gradually increase. Since it only decreases, the light intensity of the halogen lamp (62) decreases and the light emitted from the sub-mirror (63) to the document increases, so that the exposure light is uniform over the entire range of the document. It is possible to perform exposure with high intensity and completely prevent the occurrence of so-called tip baldness.

<Effect of the Invention> As described above, according to the present invention, when exposing a document set on the contact glass, the irradiation light intensity from the light emitting body is increased at a place where a so-called tip bald is conventionally generated. Therefore, there is a particular effect that it is possible to reliably prevent the occurrence of so-called tip baldness without increasing the capacity of the light-emitting body and improving the light-collecting efficiency of the main light-collecting mirror.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a configuration for carrying out a document exposure method, FIG. 2 is a vertical sectional view of a document exposure device, and FIG. 3 is a schematic diagram illustrating an internal mechanism of a copying machine. (14) ... Contact glass, (61) ... Main condensing mirror, (62) ... Halogen lamp as luminous body, (63) ...
Submirror, (D) ... manuscript

Claims (1)

[Claims] 1. A main condensing mirror, a light-emitting body, and a sub-mirror are provided, and the main condensing mirror, the light-emitting body, and the sub-mirror are moved in one direction, and the original set on the contact glass is moved to each other. In the original exposure method that exposes light by irradiating light at a reverse incidence angle to the light source, a relatively high voltage is applied to the light emitter from the start of the movement in one direction to the end of the exposure of the white reflective portion. The output light intensity of the light emitter is relatively increased by applying the voltage, and after the exposure of the white reflecting portion is completed, the output light intensity of the light emitter is changed by applying a relatively low voltage to the light emitter. An original exposure method for a copying machine, which is characterized by making it relatively small.