JPS58143665A - Contact type reading device - Google Patents

Abstract

PURPOSE:To eliminate a lens system to simplify the cnstitution of a reading device and to improve the quality of read pictures, by giving a detour to the incident light so that it crosses the electrode of a photoelectric transducer. CONSTITUTION:An contact type reading device is provided with a reading optical system 15 containing an image sensor 12 and a light source 4 which makes the light incident to a prescribed position of the system 15. The upper surface of the system 15 is covered with a slit-shaped transparent window 16 and a light shielding layer 17 which prevents the leakage of light at the areas excepting the window 16. At the same time, a prism substrate 18 having both end faces tilted with a prescribed angle and fixing members 19 and 21 that fix said both end faces are provided under the window 16 and the layer 17. In addition, a sensor 12 is formed on the lower face of the substrate and along the main scanning direction, and a light shielding layer 22 is formed to the faces excepting the one on which the sensor 12 is formed. Then an electrode 23 of the sensor 12 is provided to the layer 22. Thus a detour is given to the incident light that crosses the electrode 23, and the lens system is eliminated to simplify the constitution of a reading device.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a close-contact type reading device that reads images and information while in close contact with a document.

A reading device using a lens system is generally used in facsimile machines and the like. Figure 1 shows a typical example. The document 1 is conveyed in the sub-scanning direction (in the direction of the arrow) by the rotation of the feed roller 2 with the side to be read facing down. A platen glass 3 whose longitudinal direction coincides with the main scanning direction is disposed in the middle of the conveyance path of the original 1, and the original 1 moves while sliding in contact with the upper surface of the platen glass 3. A fluorescent lamp 4 is arranged below the platen glass 3, and a light beam 5 emitted from the lamp passes through the platen glass 3 to expose the original 1 to slit light. After passing through the platen glass 3 , the reflected light 6 from the original 1 travels downward, has its course changed by a mirror 7 , passes through a lens 8 , and forms an image on an image sensor 9 . The image sensor 9 made of MOS, COD, etc. photoelectrically converts an optical image line by line, and reading is performed using a rusk scan method.

However, in such a conventional reading device, since the size of the image sensor 9 is relatively small, it is necessary to set a large magnification of the optical image using a lens.

Therefore, there is a drawback that the optical path length becomes long and the reading device itself becomes large. Furthermore, since lenses were used, there were also disadvantages in that the amount of peripheral light in the optical image decreased and various aberrations occurred.

A contact type reader has been proposed to improve the drawbacks of the prior art. This reading device does not require a lens system. FIG. 2, in which the same parts as in FIG. 1 are denoted by the same reference numerals, shows the proposed contact type reading device. An image sensor 12 whose longitudinal direction coincides with the main scanning direction is formed on the lower surface of the substrate 11.

A plurality of electrodes 13 are led out from the image sensor 12 for operating it and obtaining necessary image signals.

With this close-contact type reader, the light 5 emitted from the fluorescent lamp 4 is
passes through the electrode 13 and the image sensor substrate 11 and exposes the lower surface of the document 1 in a slit shape. Reflected light 6 from the original 1 is reflected by the substrate 11 and enters the image sensor 12 .

However, in this proposed contact type reading device, it is necessary to illuminate the original 1 from the image sensor 12 side, so in addition to the substrate 11 on which the image sensor 12 is formed, the electrode 13 must also be transparent. It had to be transparent where it would be. If the electrodes were made transparent, not only would the device be expensive, but if the electrodes were not completely transparent, there would be shading in the read image.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a contact type reading device that does not require a transparent electrode.

In the present invention, a contact type reading device includes a light source for illuminating the document, and a light beam emitted from the light source is incident on the contact type reading device, and after being reflected by a first reflective surface, the light beam is further reflected by a second reflective surface located at a predetermined distance. It includes a prism substrate that reflects the light and emits it to the outside, and a photoelectric conversion element that is arranged at a position where the reflected light from the document surface irradiated with the light emitted from the prism substrate passes through the prism substrate and is emitted to the outside again. By bending the optical path, the light beam does not need to cross the electrode, thus achieving the above-mentioned objective.

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

FIG. 3 shows a contact type reading device according to an embodiment of the present invention. This reading device has an image sensor 12
The reading optical system 15 includes a reading optical system 15, and a fluorescent lamp 4 for causing a light beam to enter a predetermined position of the reading optical system. The upper surface of the reading optical system 15 has a slit-shaped transparent window 1.
6 and other parts are covered with a light shielding layer 17 to prevent light leakage. The document 1 is conveyed in the direction of the arrow by the feed roller 2 while slidingly contacting the transparent window 16 and the light shielding layer. On the other hand, below the transparent window 16 and the light shield 1117, there is a prism substrate 18 whose both end surfaces are inclined at a predetermined angle, and a fixing member 19 that fixes both end surfaces. '21 is placed. A one-dimensional image sensor 12 is formed on the lower surface of the prism substrate 18 along the main scanning direction. A light shielding layer 22 is formed on the lower surface other than the surface on which the image sensor 12 is formed.

The electrode 23 of the image sensor 12 is placed in the light shield 1122 . Further below, a first fixing member 19
A protective layer 24 is formed except for the vicinity of one end where . The protective layer 24 protects the image sensor 12 and the electrode 2.
This is to protect 3. The first end surface 18A of the prism substrate fixed by the first fixing member 19 of the reading optical system 15 has an inclination angle of 45 degrees with respect to the conveying direction of the original 1. Further, the second end surface 18B fixed by the second fixing member 21 has a width of approximately 60° relative to the same direction.
It has an inclination angle of degrees. A fluorescent lamp 4 for illuminating the original 1 is arranged below the first end surface 18A.

Now, when a reading operation is started with this contact type reading device, originals are fed one by one from an automatic document feeder f (ADF), not shown. The sent out document 1 is conveyed in steps by a feed roller 2 while being synchronized with the reading of the document.

As a result, image information for one line by the Rusk scan method appears one after another on the transparent window 16.

On the other hand, at the start of the reading operation, the fluorescent lamp 4 is turned on, and the emitted light beam 5 enters from the bottom surface of the prism substrate 18 and is totally reflected by the first end surface 18A.

The reflected light beam 5 changes its course 90 degrees clockwise and passes through the prism substrate 18. and second end surface 1
It is totally reflected at 8B, changes its course approximately 120 degrees counterclockwise, and enters the transparent window 16. As a result, the reading portion of the document 1 located directly above the transparent window is illuminated. The reflected light from the original 1 passes through the entrance window 16 again to the prism substrate 1.
8 and reaches the image sensor 12. Since the image sensor 12 reads the image signal in synchronization with the driving of each line of the original 1, a desired image signal can be obtained. Note that when the light beam 5 is not totally reflected at each end face, these end faces may be processed into mirrors.

As explained above, according to the present invention, since the incident light beam is routed so as not to cross the electrode of the photoelectric conversion element, the reading device can be manufactured at low cost.

Note that although a protective layer and a fixing member were used in the embodiment, these can be omitted as appropriate.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an example of a conventional reading device using a lens, FIG. 2 is a schematic configuration diagram of a conventional close-contact type reader, and FIG. 3 is a close-contact type reader according to an embodiment of the present invention. FIG. 1... Original 4... Light source 12... Image sensor 16... Transparent window 18... Prism board application Hito Fuji Xerox Co., Ltd. Representative Patent Attorney Umeo Yamauchi

Claims (1)

[Claims] A light source for document illumination, and a prism that receives the light beam emitted from this light source, reflects it on a first reflective surface, further reflects it on a second reflective surface located a predetermined distance, and emits it to the outside. A close-contact type characterized by comprising a substrate and a photoelectric conversion element disposed at a position where light reflected from a document surface irradiated by a light beam emitted from the prism substrate passes through the prism substrate and is emitted to the outside again. reading device.