JPS62100746A - Method for exposing original in copying machine - Google Patents

Abstract

PURPOSE:To prevent a copied substance from the generation of shadow at its leading end by increasing the intensity of light outputted from a light emitting body at the start of exposure of the leading end part of an original at least after the exposure of a white reflecting part. CONSTITUTION:When detecting the end of exposure of the white reflecting part 65, an original exposing position detecting means 66 outputs an original exposing position detecting signal to turn voltage to be impressed to a halogen lamp 62 from a high voltage to a low voltage with a switching means 67 and to reduce the intensity of the irradiation light. Namely, the voltage impressed to the halogen lamp 62 is increased to increase the intensity of exposing light until the end of exposure of the white reflecting part 65, and at the end of exposure of the white reflecting part 65, the voltage impressed to the halogen lamp 62 is reduced and the intensity of the exposing light is reduced to expose an original at the optimum intensity of the exposing light. In accordance with the reduction of the intensity of light irradiated from the halogen lamp 62, light irradiated from a submirror 63 to the original is increased. Consequently, a copied sheet can be prevented from the generation of shadow at its leading end.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a document 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 edge of a copy. The present invention relates to an original exposure method.

<Prior Art> Conventionally, in a copying machine, as shown in FIG. A sub-mirror (63) is installed facing the main condensing mirror (61) and the sub-mirror (63).
) is set so that light can be irradiated onto the original 1 (D) set on the contact glass (14) at opposite incident angles. Then, the reflected light from the document (D) is guided vertically downward, unnecessary portions are cut off by the slit (64), and the light is guided to an image processing section (not shown).

<Problems to be Solved by the Invention> With the document exposure device having the above configuration, in addition to exposing the document (D) using the main condensing mirror (61), the document (D) is also exposed using the sub mirror (63). This has the advantage that the light emitted from the light emitter (62) can be efficiently used for exposing the document.

However, in a copying machine, a margin of a predetermined width is formed at the leading edge of the copy to improve the peeling performance of the copy paper from the photoreceptor drum.
It is common practice to improve the peeling performance from the fixing roller, and as a specific structure for forming a margin, a white reflective part (6
5), when the light irradiated from the sub-mirror (63) to the document (D) is strong, this light is blocked by the reflecting part (65). There is a problem in that the amount of light irradiated onto the original document (D) differs greatly between the state in which it is not blocked by the reflecting portion (65), and so-called edge shadowing occurs in the obtained copy. In addition, if the light irradiated from the sub-mirror (63) to the original (D) is weak, it is necessary to increase the light intensity of the light emitter (62) itself in order to irradiate the original (D> with a predetermined amount of light). Alternatively, there is a problem in that it is necessary to improve the light collection efficiency of the main collector mirror (61).

In this case, there is a limit to the improvement in light collection efficiency, leading to an increase in cost. Furthermore, if the amount of light is increased by increasing the number of watts of the light emitting body, the problem arises that glass cooling becomes redundant, resulting in an increase in cost and an increase in the amount of current.

<Object of the invention> This invention has been made in view of the above problems,
It is possible to prevent so-called edge spots from occurring in the obtained copies without substantially increasing the wattage of the light source for exposing the original, and without particularly improving the light-collecting efficiency of the main condensing mirror. The purpose of this paper is to provide a method for exposing documents that is possible.

Means for Solving the Problems> In order to achieve the above object, the document exposure method of the present invention uses a light emitter at least at the time when the exposure of the white reflective part is completed and the exposure of the leading edge of the document is started. This increases the output light intensity.

However, the output light intensity of the light emitter may be increased by applying a high voltage to the light emitter only from the start of movement in one direction until the end of exposure of the white reflective portion.

Effect> With the original exposure method with the above configuration, during normal exposure to expose the center, rear edge, etc. of the original, sufficient exposure is achieved by the irradiation light from the main condensing mirror and the irradiation light from the sub-mirror. When exposing the leading edge of a document, increase the output light intensity of the light emitter to compensate for the amount of light emitted from the sub-mirror to obtain sufficient exposure light intensity. As a result, sufficient exposure light intensity can be obtained over the entire range of the document.

Furthermore, when exposing a white reflective area, there is no particular problem even if the exposure light intensity is too high, and the output light intensity of the light emitter does not change rapidly even if the applied voltage is reduced. Since this does not decrease, even if a high voltage is applied only until the exposure of the white reflective portion is completed, sufficient exposure light intensity can be obtained in the same device over the entire range of the document.

<Example> Hereinafter, embodiments will be described in detail with reference to the accompanying drawings showing examples.

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

(1) is the main body of the copying machine, the interior of which is divided into an upper chamber (12) and a lower chamber (13) by a partition plate (11), and an optical system for scanning and exposing a document (D) in the upper chamber (12). (2), and a copy processing section (4) for forming a copy image on copy paper CP> and a copy paper conveying section (8) are provided in the lower chamber (13).

Here, the optical system (21) is a halogen lamp (62
), main condensing mirror (61), and sub mirror (6
3), a light source (21), a plane reflecting mirror (22) (
23) (24), lens (25), and plane reflector (
26), and has a light source (21) and a flat reflector (22).
By moving the light source (231 (24) in the direction shown by the arrow hole), the document (D) on the contact glass (14) can be scanned and exposed.
), and the plane reflection mirror (22) moves within the bar, and the plane reflection v! , (23) and (24) also move in the same direction, and the moving speed of the former is set to be twice that of the latter. In the following explanation, the light source (21) and the plane anti-@ Mirrors (22) (23) (24) are attached to the optical section (2')
Collectively referred to as.

The copy paper transport section (8) includes a paper feed roller (8).
1), has a paper feed path (83), a conveyance roller (85), a registration roller (86), a heat fixing roller (88), and an ejection roller (89), and by driving the paper feed roller, the paper feed A single sheet of copy paper (P) is taken out from the cassette (16), guided to the copy processing section (4), where the toner image is transferred, and the toner image is heated by the heat fixing roller (88).
Although the configuration is such that the paper is ejected onto the pedestal (18) after fixing, the present invention is not limited to this structure. It is also possible to use a copy paper transport section having the following configuration. The copy processing section (4) includes a photosensitive drum (41) that rotates in the direction shown by C in the figure, a charger (42), a blank lamp (B) 1. A developing device (43), a transfer charge v (44), a separating member (45), and a cleaner (
46) are arranged in this order, and the charger (42
) to form an electrostatic latent image by forming an original image on the outer surface of the photoreceptor drum (41), which has been uniformly charged by a blank lamp ( ).
After removal by B), it is visualized into a toner image by a developing device @ (43), the toner image is transferred onto copy paper (P) by a transfer charge v (44), and the remaining toner is collected by a cleaner (46). However, the present invention is not limited to this configuration, and it is also possible to use a copying processing unit having another conventionally known configuration, such as one using a belt-shaped photoreceptor, for example.

FIG. 2 is a longitudinal cross-sectional view showing one embodiment of the document exposure device, which includes a main condensing mirror (61), a halogen lamp (62) as a light emitter, and a sub-mirror (63).

The main condensing mirror (61) is formed into a concave mirror shape as a whole, and has a halogen lamp (62) in its inner part.
is installed. Then, the light X reflected by the first region (see R1 in the figure) of the main condensing mirror (61)
Pass the original through the contact glass (14) as it is (
The exposure area of D) is irradiated, and the main condensing mirror (6
The light Y reflected by the second region (see R2 in the figure) of 1) becomes parallel to the contact glass (14) (although strictly speaking, it is slightly convergent) as shown in the figure. This light Y
A sub-mirror (63) erected in an inclined manner is installed at the position where lj! The exposure area of the image (D>) is irradiated.

Note that the original (D>
can be illuminated.

Further, (64) is a slit formed between the main condensing mirror (61) and the sub-mirror (63), which can restrict the passage range of the reflected light from the original (D>). There is.

Further, (65) is a white reflective part 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), in which a switch is made to selectively output different voltages by inputting a signal from the original exposure position detection means (66). means (67);
) is applied to the halogen lamp (62).

To explain in more detail, the document exposure position detection means (
66) is composed of a switch that detects the moving position of the optical section (2'), a pulse counter that detects the moving time of the optical section (2'), etc., and controls the exposure of the white reflective section (65). When it is detected that the exposure has ended, a document exposure position detection signal is output, and the voltage applied to the halogen lamp (62) is changed to
Switching from high voltage to low voltage by the switching means (67),
The intensity of the irradiated light can be reduced.

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

Regarding so-called tip shadowing, even if the voltage applied to the halogen lamp (62) is reduced to illuminate the document (D) set on the contact glass (14), the intensity of the irradiated light gradually decreases. Therefore, overall, the intensity of the irradiated light from the halogen lamp (62) becomes smaller, and the irradiated light from the sub-mirror (63) to the document increases, so that the exposure light is uniform over the entire range of the document. By performing high-intensity exposure, it is possible to completely prevent so-called tip shadowing.

<Effects of the Invention> As described above, the present invention increases the intensity of irradiated light from the light emitting body at a location where so-called tip shadowing has conventionally been considered to occur when exposing an original set on a contact glass. This has the unique effect of reliably preventing so-called tip shading without increasing the capacity of the light emitter or improving the light collection efficiency of the main collector mirror.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a configuration for carrying out an original exposure method, FIG. 2 is a four-dimensional view of the original exposure device, and FIG. 3 is a schematic diagram illustrating the internal mechanism of a copy line. (14)... Contact glass, C61)... Main condensing mirror,

Claims (1)

[Claims] 1. Main condensing mirror, light emitter, and sub and a main condensing mirror, Move the light emitter and submirror in one direction. Set it on the contact glass while moving it. Light is applied to the printed original at opposite angles of incidence. In the original exposure method that exposes by irradiating At least the exposure of the white reflective area is completed. When exposure of the leading edge of the original begins Increasing the output light intensity of the light emitter at A document exposure method of a copying machine characterized by Law. 2. Start moving in one direction and then turn the white counter Emits light only until the end of exposure of the radiation area Luminous body by applying high voltage to the body The above patent claim increases the output light intensity of The original exposure method of the copying machine described in the range 1. Law.