JPH02283166A - Original irradiation device - Google Patents

Abstract

PURPOSE:To prevent reading of shadow of an original by providing a mirror reflecting a light from a fluorescent light opposite to the fluorescent light and irradiating a read position from the side opposite to the fluorescent light with respect to the optical axis of a read reflection light. CONSTITUTION:A fluorescent light 21 irradiates a read position A in an oblique direction directly, and a mirror 22 reflects the light from the fluorescent light 21 to irradiate the read position A from the opposite side to the fluorescent light 21 with respect to the optical axis B of a read reflecting light. The path of the reflected light from an original 12 is changed by a reflecting mirror 15 and the image is formed on a read element 17 by a condenser lens 16, and the image is read by the read element 17 and a drive board 18 or the like. Since the aperture of the fluorescent light 21 is positioned to a prescribed angular position accurately, the read position A is always irradiated by a prescribed luminous quantity to attain excellent reading. When the ridge of the original 12 is read, since the ridge is irradiated from both sides, no shadow is caused and a problem of reading the ridge as a black line is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a document irradiation device for illuminating the surface of a document before reading the document in an image scanner, a copying machine, a facsimile machine, or the like.

2. Description of the Related Art Conventionally, as shown in FIG. 4, a document reading device irradiates a document 2 on a transparent document table 1 with a document irradiation device equipped with a fluorescent lamp 3, and uses reflected light from the document 2 to emit light reflected from the document 2. The optical path is changed by a reflecting mirror 4, an image is formed on a reading element 6 by a condensing lens 5, the reading element 6 generates an electric signal by photoelectric conversion, and the image is processed by a drive board 7. has been done.

In this case, main scanning is performed by electrically scanning one line, and sub-scanning is performed using an optical system consisting of a fluorescent lamp 3, a reflecting mirror 4, a condensing lens 5, a reading element 6, a drive board 7, etc. This is done by moving the unit 8 relative to the document 2.

The document irradiation device used in the document reading device usually uses a fluorescent lamp 3, and as shown in FIG. 5, this fluorescent lamp 3 is arranged so as to illuminate the document 2 from an oblique direction. It is common that

In addition, a fluorescent lamp preheater 9 is attached to the fluorescent lamp 3, and by keeping the fluorescent lamp 3 at a constant temperature, it can change from a fluorescent lamp state to a lighting state and emit the necessary amount of light in a short time. That's what I do. Incidentally, in FIG. 5, IO is a document holder.

Problems to be Solved by the Invention However, with this configuration, there is a problem in that when the edges of the document are read, the edges of the document are read as black lines.

The above problem arises for the following reasons. That is, since the original is illuminated with oblique light, a shadow of the original is generated near the edge of the original. Since scanning uses reflected light perpendicular to the original, the shadows on the original are read, and information that should not be there is read as black information.

As a countermeasure for this, it is conceivable to irradiate the reading position of the document 2 vertically with a fluorescent lamp 3 and read oblique light, as shown in FIG. However, in this method, if the original 2 floats above the original reading surface, the reading point will be shifted, which will actually result in deterioration of the image quality.

Furthermore, as shown in FIG. 7, a method can be considered in which a pair of fluorescent lamps 3.3 illuminate the reading position of the original symmetrically, and the reflected light perpendicular to the original is read. However, in this case, twice as many fluorescent lamps, fluorescent lamp sockets, fluorescent lamp preheaters, lamp lights, and lights are required, and problems regarding cost and space remain.

Although it is not intended to prevent shadows on the edges of the document, a fluorescent light and a mirror are placed across the document reading position, and the fluorescent light directly illuminates the document reading position from an oblique direction. A device is known in which the light from the fluorescent lamp is reflected by a mirror to illuminate the reading position of the original in an oblique direction from the opposite side (for example, Japanese Patent Laid-Open No. 53-861
No. 10, JP-A No. 62-45271). This device uses a mirror to illuminate the document from the opposite side of the fluorescent light, making it possible to eliminate shadows at the edges of the document. However, in this type of device, when a type of fluorescent lamp that emits light only from an aperture provided in a part of the circumference is used, there is a possibility that the aperture position of the fluorescent lamp may deviate from the designed position. In particular, it has been found that a problem arises in that the amount of light reflected by the mirror changes greatly, and therefore the amount of light irradiated on the document as a whole changes, causing reading errors. Generally, a fluorescent lamp is held by inserting the pins provided at both ends into the fluorescent lamp socket and rotating them so that they engage with the receiver (generally composed of a leaf spring) of the fluorescent lamp socket. In this case, it is made so that there is some leeway in the direction of rotation. For this reason, when the fluorescent lamp is set in the fluorescent lamp socket, the aperture of the fluorescent lamp is not necessarily in the correct position, and as a result, the amount of light directed toward the mirror may differ from the designed value, and the original A problem arose in that the amount of irradiation light differed from the design value.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a document irradiation device that can prevent shadows on a document from being read and can easily keep the amount of document irradiation light constant. With the goal.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention is directed to a fluorescent lamp that illuminates the reading position of the document surface from an oblique direction, and reflects the light from the fluorescent lamp. A mirror is provided that illuminates the reading position from the opposite side of the fluorescent lamp with respect to the optical axis of the reflected light, and the fluorescent lamp has an arcuate portion attached along the circumferential surface of the fluorescent lamp and a mirror bent from one end of the mirror. attaching a positioning plate having a bent portion by fixing a fluorescent lamp preheater from outside the circular arc portion of the positioning plate so that the bent portion is in a predetermined position with respect to the aperture of the fluorescent lamp; ,
The apparatus is provided with a bracket that positions the positioning plate at a predetermined position in the rotational direction when it is attached to the fluorescent lamp socket and rotated.

Effect of the present invention With the above-described configuration, a fluorescent lamp directly irradiates the reading position of the document from one side with respect to the optical axis of the read reflected light.
The mirror reflects the light from the fluorescent lamp and illuminates it from the opposite side, eliminating shadows around the edges of the document. When setting the fluorescent lamp in the fluorescent lamp socket, even if the fluorescent lamp has some margin in the rotation direction relative to the fluorescent lamp socket, the positioning plate of the fluorescent lamp will be rotated by the bracket. By rotating the aperture of the fluorescent lamp until it is blocked, the position of the aperture of the fluorescent lamp in the rotational direction can be accurately determined, and therefore, the amount of light irradiated on the document can be made constant.

Example Hereinafter, the present invention will be described in detail as shown in the drawings.

FIG. 1 is a partial schematic perspective view of a document reading device equipped with a document irradiation device according to an embodiment of the present invention, FIG. 2 is a perspective view of essential parts of the document irradiation device, and FIG. 3 is a perspective view of the document irradiation device and It is a schematic sectional view of the vicinity.

In FIGS. 1 to 3, 11 is a transparent document table, 12 is a document placed on the document table 11, 13 is a document holder, and I
4 is a document irradiation device that irradiates the reading position A on the document surface; 15;
A reflecting mirror 16 that converts the direction of the reflected light from the original is a condenser lens that focuses the reflected light from the original on a reading element 17, and 17 is a reading element that photoelectrically converts the reflected light from the original.
Reference numeral 18 denotes a dry board for controlling the reading element, and 19 carries the original irradiation device 14, the reflecting mirror 15, the condensing lens I6, the reading element 17, the drive board 18, etc., and moves relative to the original platen 11. It is an optical unit.

The document irradiation device 14 includes a fluorescent lamp 21 that illuminates the reading position A on the document surface from an oblique direction, a fluorescent lamp socket (not shown) for attaching the fluorescent lamp 21, and a fluorescent lamp 21 facing the fluorescent lamp 21. It is provided with a mirror n which reflects the light from the fluorescent lamp 21 and illuminates the reading position A from the side opposite to the fluorescent lamp 21 with respect to the optical axis B of the reflected light. In the fluorescent light 21,
Positioning plates O are attached near both ends, respectively, and a fluorescent lamp preheater U is attached over almost the entire length of the fluorescent lamp 21. The positioning plate is made of a metal plate with a thin wall thickness (for example, about 0.1 to 0.2B thick), and has a circular arc portion 23A attached along the circumference of the fluorescent lamp and a bent portion bent from one end of the plate. 23B.

The fluorescent lamp preheater 24 is attached to the fluorescent lamp 21 from above the circular arc portion 23A of the positioning plate portion.

This fluorescent lamp preheating heater uses its own elasticity to heat the fluorescent lamp 2.
1, and is configured so that the opening is less than 180 degrees. Still, the positioning plate portion can be fixed to the fluorescent lamp 21 by attaching the fluorescent lamp preheater 24 to the fluorescent lamp 21. Here, the positioning plate part is arranged at a position where its bent part nB contacts one edge 24A of the fluorescent lamp preheating heater n, and the one edge 24A of the fluorescent lamp preheating heater n comes into contact with the fluorescent lamp preheating heater n. They are installed a predetermined distance apart. Thus, the positioning plate portion is fixed in a predetermined position relative to the aperture of the fluorescent lamp 21.

In FIG. 3, a bracket portion is provided below the fluorescent lamp 21. As shown in FIG. This bracket 5 is designed so that when the fluorescent lamp 21 is rotated in the direction of the arrow and set in the fluorescent lamp position, it can be engaged with the bent portion 23B of the positioning plate portion to position it at a predetermined position. The position of the aperture of the fluorescent lamp 21 is set at a predetermined position in the rotational direction when the positioning plate is brought into contact with the bracket 25 for positioning.

The operation of the document reading device configured as above and the document irradiation device used therein will be described below.

First, the attachment of the fluorescent lamp preheater 24 and the positioning plate portion to the fluorescent lamp 21 and the attachment operation of the fluorescent lamp 21 will be described. First, the circular arc portion 23A of the positioning plate portion is inserted near both ends of each fluorescent lamp preheater U, and the bent portion 23B thereof is brought into contact with one edge 24A of the fluorescent lamp preheater U for positioning.

Next, the fluorescent lamp preheating heater 24 fitted with the positioning plate O
Then, the fluorescent lamp 21 is fitted so that its aperture is at a predetermined distance from one edge 24A of the fluorescent lamp preheater tube. As a result, the positioning plate n and the fluorescent lamp preheating heater 4 are fixed at predetermined positions relative to the fluorescent lamp 21.

Next, this fluorescent lamp 21 is inserted into a fluorescent lamp socket (not shown) from the side, and rotated in the direction shown by the arrow in FIG. engage the receiver. At this time, place the fluorescent lamp 21 on the bent part 2 of the positioning plate.
Rotate until 3B contacts the placket 5 and stop at that position. As a result, the aperture of the fluorescent lamp 21 is positioned at a fixed position in the rotational direction, and becomes a predetermined position with respect to the reading position A and the mirror n.

When reading a document, the fluorescent pair 2 is used as shown in Figure 3.
1 directly illuminates the reading position A from an oblique direction, and the mirror ρ reflects the light from the fluorescent pair 21 to illuminate the reading position A opposite to the optical axis B of the read reflected light from the fluorescent pair 21. Irradiate from the side. The reflected light from the original is changed in its optical path by a reflecting mirror 15, and is imaged onto a reading element 17 by a condensing lens 16.
Reading is performed by the reading element 17, drive board 18, and the like. Here, as described above, since the aperture of the fluorescent pair 21 is accurately positioned at a predetermined angular position, the document reading position A is always irradiated with a constant amount of light, and good reading is performed. Also, when reading the edges of a document,
Since the edge is illuminated from both sides, there are no shadows,
This prevents the edges from being read as black lines.

Effects of the Invention As is clear from the above description, the present invention provides, in addition to a fluorescent pair that irradiates the reading position on the document surface from an oblique direction, a fluorescent pair that emits light from the fluorescent pair opposite to the fluorescent pair. Since a mirror is provided that reflects light to read the reading position from the side opposite to the fluorescent pair with respect to the optical axis of the reflected light, when illuminating the edge of the document, it is possible to avoid shadows on the edge and produce good illumination. Readable. Moreover, a positioning plate having a circular arc portion attached along the circumferential surface of the fluorescent pair and a bent portion bent from one end thereof is attached to the fluorescent pair at a predetermined position by a fluorescent pair preheater, Furthermore, since a bracket is provided to position the positioning plate in a predetermined position when the fluorescent pair is attached to the fluorescent lamp socket, the fluorescent pair can be positioned easily when the fluorescent pair is inserted into the fluorescent pair socket. By rotating the plate until it is prevented from rotating by the bracket, the aperture of the fluorescent pair can be accurately positioned, and the amount of light irradiated on the document can be made constant.

[Brief explanation of drawings]

FIG. 1 is a partial schematic perspective view of a document reading device equipped with a document irradiation device according to an embodiment of the present invention, FIG. 2 is a perspective view of essential parts of the document irradiation device, and FIG. 3 is a perspective view of the document irradiation device and 4 is a partial schematic perspective view of a conventional document reading device, FIG. 5 is a sectional view of its main part, and FIGS. 6 and 7 each show other examples of the conventional device. FIG. 5 is a sectional view of the same part as FIG. 5; DESCRIPTION OF SYMBOLS 11... Original table, 12... Original, 13... Original valve, 14... Original irradiation device, 15... Reflection mirror,
16... Condensing lens, 17... Reading element, 18...
- Drive circuit, 19... Optical unit, 21... Fluorescent pair, η... Mirror, η... Positioning plate, 23A.
... Arc part, 23B... Bent part, 24... Fluorescent pair preheater, 24A... - Edge, 5... Bracket. Name of agent: Patent attorney Shigetaka Awano and one other person

Claims (1)

[Claims] A fluorescent lamp that illuminates a reading position on a document surface from an oblique direction; and a positioning plate attached to the fluorescent lamp, which includes an arcuate portion attached along the circumferential surface of the fluorescent lamp and a bent portion bent from one end thereof. a fluorescent lamp preheater that is attached to the fluorescent lamp from the outside of the circular arc portion of the positioning plate and fixes the positioning plate to the fluorescent lamp, and a fluorescent lamp preheater that is attached to the fluorescent lamp at a predetermined position and rotated. a bracket that positions the positioning plate at a predetermined position in the rotational direction when the positioning plate is rotated; and a bracket that is provided opposite the fluorescent lamp and that reflects light from the fluorescent lamp to read the reading position on the document surface and an optical axis of the reflected light. and a mirror that emits light from a side opposite to the fluorescent lamp.