JPH0244275Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is a document illumination device for forming a document optical image by illuminating the document in a band shape, which is used in, for example, a copying machine, a facsimile machine, an image reading device, etc. In particular, the present invention relates to a document illumination device equipped with a sensor for measuring light amount.

[Background of the idea]

For example, in a copying device such as an electrophotographic copying machine, a linear light source and a gutter-shaped reflecting mirror surrounding the linear light source form a band-shaped illumination area on the surface of the copy document, and this band-shaped illumination area is directed against the surface of the document. While moving relative to each other, a light image of the original is formed on a rotating drum-shaped photoreceptor to form a latent image, this latent image is developed with toner, and then transferred and fixed onto a support such as paper. to form a copy image.

An example of such a document illumination device is shown in FIG. 1
1 is a linear light source, and 12 is a gutter-shaped reflecting mirror. The gutter-shaped reflecting mirror 12 is arranged so as to surround the linear light source 11, and collects the emitted light from the linear light source 11 to illuminate a belt-shaped illumination area on the copy document 14 placed on the document table 13. form 15. 22 is a reflecting mirror 12
A slit forming member 22 is provided integrally with the slit forming member 22, and a slit 21 is provided in the slit forming member 22. This slit 21 is located directly below the illumination area 15. 31, 32, 33, and 34 are plane reflecting mirrors, 35 is an imaging lens, and 40 is a rotating drum-shaped photoreceptor. The original light image from the illumination area 15 is
Slit 21, plane reflecting mirror 31, imaging lens 3
5. The light is projected onto the photoreceptor 40 via the plane reflecting mirrors 32, 33, and 34. The strip-shaped illumination area 15 is the original 1
The document table 13 or the document illumination light is moved so that the document table 13 or the document illumination light is scanned relative to the photoreceptor 4, and the document light image of the entire area of the document 14 is scanned by the photoreceptor 40. project upwards.

[Problem that the invention attempts to solve]

However, manuscripts come in various colors,
Alternatively, there are documents with different shading, and in order to form proper copy images for all of these documents, it is preferable to illuminate each document with a corresponding amount of light. In order to achieve this, conventionally, the reflecting mirror 12 is provided with a through hole 50 through which a part of the reflected light from the illumination area 15 passes. A sensor 70 for measuring the amount of light is placed at a position overlooking the illumination area 15, and by first pre-illuminating the original 14, the amount of light reflected from the illumination area 15 is measured by the sensor 70, and based on the measurement result, the linear light source is 11
Then, the original 14 is actually illuminated with the determined lighting voltage, thereby projecting an optical image of the original onto the photoreceptor 40.

However, in the preliminary illumination performed to measure the amount of light by the sensor 70, the reflector 1
A phenomenon occurs in which the light passing through the through hole 50 of No. 2 is scattered by the outline of the through hole 50, and this scattered light may be projected onto the photoreceptor 40. In this case, a good copy image is formed. Can not do it.

[Purpose of invention]

The present invention was developed based on the above-mentioned circumstances, and its purpose is to make it possible to measure the amount of light using a sensor for measuring light amount with a simple configuration, and to prevent the projection of scattered light onto the photoreceptor when measuring the amount of light. An object of the present invention is to provide a document illuminating device that can easily prevent the above problems.

[Means for solving problems]

The document illumination device of the present invention includes a linear light source, and a gutter-like structure that is arranged to surround the linear light source and that collects the emitted light from the linear light source to form a belt-shaped illumination area on the document surface. In a document illuminating device comprising a reflecting mirror and a holder disposed on the back side of the reflecting mirror and including a reflecting mirror holding plate holding the reflecting mirror, the reflecting mirror is provided with a light beam from the illumination area to the reflecting mirror. A through hole is provided through which a part of the reflected light passes through, a projection opening is formed by cutting and raising a portion of the mirror holding plate opposite to the through hole, and the illumination area is transmitted through the projection opening and the through hole. The present invention is characterized in that a sensor for measuring the amount of light is provided at a desired position, and a cut-and-raised portion related to the projection opening is used as a light shielding plate for scattered light passing through the projection opening.

[Function and effect of the idea]

According to the present invention, a holder including a reflector holding plate on which the reflector is held is provided on the back side of the reflector to hold the reflector and prevent the reflector from receiving reflected light from the illuminated area. A through hole is provided through which a part of the light passes through, and a projection opening is formed by cutting and raising the part of the reflector holding plate facing this through hole, and the illumination area is positioned through the projection opening and the through hole for measuring the amount of light. Since the sensor is provided, part of the reflected light from the illumination area can be reliably received by the light amount measurement sensor through the through hole and the projection port, and the cut-up part related to the projection port can be reliably received by the light amount measurement sensor. Since the light shielding plate is used for the scattered light passing through, it is possible to block the scattered light passing through the projection aperture with an extremely simple configuration, and as a result, there is no adverse effect on the original light image from the illuminated area. It becomes possible to measure the amount of reflected light using a sensor for measuring the amount of light, and it is possible to illuminate the document with an appropriate amount of illumination light depending on the document.

[Specific examples]

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

FIG. 1 is an explanatory diagram showing an embodiment in which the document illumination device of the present invention is applied to an electrophotographic copying machine.

11 is a linear light source, and 12 is a reflecting mirror. The linear light source 11 is, for example, a rod-shaped halogen incandescent light bulb equipped with a partially emitting filament in which light emitting parts and non-emitting parts are arranged alternately. The reflecting mirror 12 is made of aluminum, for example, and has a gutter-like shape as a whole, and is arranged so as to surround the linear light source 11, and condenses the emitted light from the linear light source 11, and directs it to the document table 13 made of transparent glass. A strip-shaped illumination area 15 is formed on the document 14 placed above.

20 is a reflecting mirror holding plate, and this reflecting mirror holding plate 20 is arranged on the back side of the reflecting mirror 12. The reflecting mirror 12 is fixed to the reflecting mirror holding plate 20, and a holder (not shown) for the linear light source 11 is fixed thereto, and the linear light source 11 is held by the holder. This reflecting mirror holding plate 20 forms part of a holder (not shown in its entirety), and each component is held in its entirety by this holder. A slit 21 is provided directly below the illumination area 15 on one end side of the reflector holding plate 20. 31,3
2, 33, and 34 are plane reflecting mirrors, 35 is an imaging lens, and 40 is a rotating drum-shaped photoreceptor.

The original light image from the illumination area 15 is transmitted to the slit 2
1. The light is projected onto the photoreceptor 40 via the plane reflecting mirror 31, the imaging lens 35, and the plane reflecting mirrors 32, 33, and 34. The document table 13 or the document illumination light is moved so that the belt-shaped illumination area 15 is scanned relative to the document 14, and a document light image of the entire document 14 is projected onto the photoreceptor 40.

Reference numeral 50 denotes a through hole, which is formed in a portion of the reflecting mirror 12 located diagonally below the illumination area 15, and allows part of the reflected light from the illumination area 15 to pass through. 60 is a projection port, and this projection port 60 is formed by cutting and raising a portion of the mirror holding plate 20 that faces the through hole 50 on the side opposite to the side where the through hole 50 is located;
The cut and raised portion is used as a light shielding plate 61 for scattered light passing through the projection aperture 60. Specifically, the cut-and-raised portion, that is, the light-shielding plate 61 is positioned between the projection aperture 60 and the optical path L from the illumination area 15 to the plane reflecting mirror 31 via the slit 21, and the The cut and raised portion is positioned so as to extend substantially parallel to the optical path L.

Reference numeral 70 denotes a sensor for measuring the amount of light, and this sensor 70 measures the amount of reflected light from the illumination area 15 that has passed through the through hole 50 and the projection opening 60. Although not shown, this light amount measurement sensor 70 constitutes a part of the power supply device for the linear light source 11, and the power supply device adjusts the lighting voltage of the linear light source 11 based on the amount of light received by the light amount measurement sensor 70. For example, feedback control is performed so that the amount of received light always remains at a constant value.

The document illuminating device having the above configuration illuminates the document 14 in the following manner. First, while the optical path from the illumination area 15 to the photoreceptor 40 is temporarily interrupted, the linear light source 11 is turned on to preliminarily illuminate the original 14 . During this preliminary illumination, the amount of light reflected from the document 14 that has passed through the through hole 50 and the projection opening 60 from the illumination area 15 is measured by the light amount measuring sensor 70. Based on the measurement result of the light amount, the lighting voltage of the linear light source 11 is feedback-controlled. Next, with the optical path from the illumination area 15 to the photoreceptor 40 fully open, the original 14 is illuminated by lighting the linear light source 11 with a feedback-controlled lighting voltage, and the optical image of the original from the illumination area 15 is is projected onto the photoreceptor 40, thereby forming a latent image corresponding to the original 14 on the photoreceptor 40.

According to the embodiments described above, a holder including a reflector holding plate 20 disposed on the back side of the reflector 12 is provided to hold the reflector 12 and prevent the reflector 12 from receiving reflected light from the illumination area 15. A through-hole 50 is provided through which a portion of the reflecting mirror holding plate 20 passes, and a portion of the mirror holding plate 20 that faces the through-hole 50 is formed through the through-hole 50.
Cut and raise the projection port 6 on the side opposite to where it is located.
0 is formed and the light quantity measurement sensor 70 is provided at a position where the illumination area 14 is viewed through the projection opening 60 and the through hole 50. The light can be reliably received by the light amount measuring sensor 70 through the light amount measuring sensor 70 through the light amount measuring sensor 70.
By controlling the lighting voltage of the linear light source 11 based on the light amount value detected by , it is possible to illuminate the document 14 with an appropriate amount of illumination light depending on the type of document 14 .
Since the cut and raised portion to form the projection aperture 60 is used as the light shielding plate 61 for the scattered light passing through the projection aperture 60, the scattered light passing through the projection aperture 60 can be blocked with an extremely simple configuration. The scattered light can be prevented from reaching the photoconductor 40, and as a result, a clear electrostatic latent image that faithfully corresponds to the original optical image can be formed on the photoconductor 40, and the ultimate It becomes possible to form a clear copy image with appropriate image density.

Although one embodiment of the present invention has been described above, the document illumination device of the present invention is not limited to copying machines;
It can also be applied to facsimiles, image reading devices, etc. Further, the specific configuration of the reflecting mirror and the specific configuration of the linear light source can be changed as necessary. For example, the reflecting mirror may be formed of a curved surface, a flat surface, or a combination thereof. For example, the linear light source may be formed by arranging a plurality of small light bulbs in a row. In addition, an auxiliary reflector is fixed to a reflector holding plate at a position opposite to the trough-shaped reflector with respect to the optical path of the original light image from the illumination area, and the auxiliary reflector allows the trough-shaped reflection to occur. The light reflected from the mirror may be reflected again and projected onto the illuminated area for illumination.

[Brief explanation of drawings]

FIG. 1 is an explanatory sectional view showing an embodiment of the document illumination device of the present invention applied to a copying machine, and FIG.
The figure is an explanatory cross-sectional view showing a conventional document illumination device. 11... Linear light source, 12... Reflector, 13...
Original table, 14... Original, 15... Illumination area, 20
... Reflector holding plate, 21 ... Slit, 31,3
2, 33, 34...Flat reflecting mirror, 35...Imaging lens, 40...Photoconductor, 50...Through hole, 60
...Projection port, 61... Light shielding plate, 70... Sensor for measuring light amount.

Claims (1)

[Claims for Utility Model Registration] A linear light source, and a gutter-shaped gutter arranged to surround the linear light source that condenses the emitted light from the linear light source to form a strip-shaped illumination area on the document surface. In a document illumination device comprising a reflecting mirror and a holder disposed on the back side of the reflecting mirror and including a reflecting mirror holding plate holding the reflecting mirror, the reflecting mirror is provided with a light source from the illumination area. A through hole is provided through which a part of the reflected light passes through, a projection opening is formed by cutting and raising a portion of the mirror holding plate opposite to the through hole, and the illumination area is transmitted through the projection opening and the through hole. What is claimed is: 1. A document illuminating device, characterized in that a sensor for measuring light amount is provided at a position desired to provide light, and a cut-and-raised portion related to the projection opening is used as a light shielding plate for scattered light passing through the projection opening.