JPS6363274A - Reader - Google Patents

Abstract

PURPOSE:To prevent unnecessary light from the surfaces of a prism etc., to a solid-state image pickup element and irregular reflection in a prism and to obtain a color picture with an excellent balance by forming the prism and the solid-state image pickup element with an adhesive, etc., integrally and applying a light shielding member to the outer edge part of said body. CONSTITUTION:The light shielding member 30 such as a light shielding type black paint is applied to all the outer edge parts of the integrally formed prism 22 and solid state image pickup elements C-ch CCD2 and R-ch CCD27. Thus the unnecessary light that tries to make incident on and enter into both the prism and the light receiving parts of the CCDs from the surface of the prism, etc., can be completely prevented. Besides to that, the inner reflection of the prism 22 can be prevented. For sticking the solid-state image pickup elements to the prism 22, a two liquid type adhesive and a photosetting adhesive by ultraviolet rays are effective. The adhesive is mixed with the light shielding member 30. For bonding the prism and CCDs, they are temporarily bonded with the adhesive, after which they are regularly bonded by the adhesive mixed by the light shielding member 30. As a result the bonding and light shielding effects can be improved.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a reading device such as an image forming apparatus such as a facsimile machine or a copying machine, and more specifically, the present invention relates to a reading device such as an image forming device such as a facsimile machine or a copying machine, and more specifically, the present invention relates to a reading device such as an image forming device such as a facsimile machine or a copying machine. The present invention relates to a reading device that reads a document image using a solid-state imaging device such as an image sensor.

[Background of the invention]

In a reading device, a light image of a document surface obtained by exposure scanning is generally formed on a solid-state imaging device such as an image sensor located around an optical axis via an imaging lens system. For example, in the reading device of a color image forming apparatus, the light image of the document surface obtained by exposure scanning is passed through an imaging lens system, and then separated into lights by a light splitting means such as a prism installed behind the lens system. The image is formed on an image sensor that receives the light. Here, the exposure scanning of the reading device in which the document table is fixed and the optical f system is moved is performed by irradiating the document placed on the platen plus in a strip shape with a moving light source. The image is reflected and guided by a first mirror that moves together with the light source, and second and third mirrors provided on a movable mirror unit, and an image is also fixed behind it through a fixed imaging lens. image is formed on the image sensor. A rod-shaped halogen lamp or fluorescent tube is used as a light source. Fluorescent tubes are often used because halogen lamps generate a lot of heat when continuously lit. In addition to the light flux of the original image required to form an image on the line image sensor, the scanning optical system and imaging lens mentioned above are equipped with internal reflections and diffused reflections of indoor light from the platen glass and light from light sources such as fluorescent tubes. When unnecessary light (miscellaneous light) generated by other sources enters the line image sensor, it weakens the contrast of the image, further reduces the color balance in the case of color images, and lowers the image quality of the scanned document. It's so obvious.

[Problems to be solved by the invention]

The present invention is a reading device that illuminates a document surface with a light source such as a fluorescent tube and reads the illuminated document image.The present invention is a reading device that prevents constant light from entering a solid-state image sensor as much as possible, thereby obtaining good image quality. The purpose is to provide

[Means to solve the problem]

The present invention is an attempt to solve the above-mentioned problems, and consists of a light source that irradiates an original placed on a platen glass and a first mirror, and two sheets arranged in a 7-shape. A movable mirror unit consisting of a mirror,
A reading device comprising a fixed imaging lens, a light splitting prism provided behind the fixed imaging lens, and a solid-state imaging device, and configured to form the original image on the solid-state imaging device, the light splitting prism and the solid-state imaging device This is achieved by a reading device characterized in that the element is integrated and its outer edge is coated with a light-shielding coating material.

【Example】

Before explaining the reading device of the present invention, the image forming device will first be explained. Fig. 4 shows the configuration of an image forming apparatus equipped with the image reading device of the present invention, as shown below. A color image is formed. In FIG. 4, A is a reading device, B is a writing unit,
C is an image forming section, and D is a paper feeding section. In the reading device A, 1 is a platen plus, and a document 2 is placed on this platen glass 1. The document 2 is illuminated by fluorescent lamps 5 and 6 provided on a carriage 4 that moves on a slide rail 3. Movable mirror unit 8
mirrors 9 and 9' are provided and move on the slide rail 3, and the first mirror 7 provided on the carriage horn 4
In combination with this, the optical image of the document 2 on the platen glass 1 is guided to the lens reading unit 20. The carriage 4 and the movable mirror unit 8 are moved by pulleys 11, 12, 13, and 14 driven by a stepping motor 10 via a wire 15, respectively.
Driven in the same direction at a speed of ①. Standard white plates 16 and 17 are provided on the back side of both ends of the platen glass 1, and are configured so that an onion quasi-white signal can be obtained before the start of original reading scanning and after the end of scanning. The lens reading unit 20 includes a lens 21 as a reading lens system, a prism 22 as a light decomposition means, a first reading board 24, a red channel (hereinafter referred to as R-cl+) CCD 27 as a line image sensor, and a second CCD 27 as a line image sensor.
It is composed of a reading board 26 and a cyan channel (hereinafter referred to as C-ch) CCD 25. The original optical image transmitted by the first mirror 7, mirror 9, and mirror 9' is focused by a lens 21, and separated into an R-cb image and a C-cb image by a gicroic mirror provided in a prism 22. , 11 C-c provided on the reading board 24
The image is formed on the light receiving surfaces of the R-ch CCD 27 provided on the h CCD 25 and the second reading board 26, respectively. For the fluorescent lamps 5 and 6, commercially available warm white fluorescent lamps are used as light sources to prevent emphasis or attenuation of specific colors when reading color originals, and 40° C. fluorescent lamps are used to prevent flickering.
It is turned on by a high frequency power source of K 11 z, and is kept warm by a heater using a POSISTOR in order to maintain the temperature of the tube wall at a constant temperature or to increase the ohm. Said C-ah CCD 25 and R-ah CCD 2
The image signal outputted from 7 is processed through a signal processing section (not shown), and a color signal separated according to the color of the toner is output and input to the writing section 22) B. Each of the laser beams generated is sequentially projected onto the circumferential surface of the photosensitive drum 31, and a color image using three color toners is formed through development processing for each projection. Next, the color image on the circumferential surface of the photoreceptor drum 31 is transferred to a recording paper conveyed from the paper feed section at a transfer separation pole 32, and then the recording paper is separated, passed through a fixing device 33, and then discharged outside the station. to finish copying the color image. Figure Pt5s shows the main parts of the supplementary part of the image reading device A described in IIT, and the machine frame that accommodates the reading device A is constructed as follows. The member forming the bottom surface of the reading device A is integrally formed with vertical side plates 51 and 52 facing forward and backward in the moving direction of the moving optical system, and has a pair of bent portions 51a provided at the left and right ends, respectively. A pair of left and right frame plates 53 are symmetrically attached and fixed to and 52a, and constitute the machine frame of the reading device A together with the bottom surface portion. On the other hand, the side plates 51 and 52 are bent g51b in such a state that the pair of left and right boards 54, which have formed U-shaped spaces 54a by bending, project the spaces 54a to the outside of the machine frame, respectively; 52b and the inner surface of the frame plate 53 with screws X, and the platen glass 1 is placed and fixed on the upper surface thereof. The carriage 40, which is a movable mirror unit, and the movable mirror unit 80 are housed inside the substrate 54, and both R portions 40a and 80a of each are made of polyacetal or PPT 73 attached to the bottom surface thereof.
It is mounted so as to be able to slide on a slide rail 3 made of high-density polyethylene or the like laid down on the bottom surface of the space 54a by means of a slide dowel (not shown) made of quartz or the like. The carriage 40 and movable mirror unit 80 are guided and held in a straight line by a member (not shown) separate from the slide rail 3. Furthermore, notches 54b and 54c are provided at both ends of the substrate 54.
A fixed boo 912 is provided facing the notch 54b, while a tension lever 13a pivoted to the frame plate 53 is biased counterclockwise at a position facing the notch 54c. Pulleys 13 are respectively arranged on the outside of the substrate 54. Further, on the frame board 53 facing the outside of the board 54, there are 8
The mounting is supported so that a stepping motor 10 that drives the optical system can rotate a pulley 11, which is also a drive pulley, which is also pivoted on a frame plate 53 via a timing bell 10a. In this way, the wire 15 that moves and controls the moving light system is wound around the pulley 11, and one end of it is fixed on both Rg40a of the carriage 40 after going around the pulley 12, and is further fixed on both wings of the movable mirror unit 80. After going around the lower pulley 14 on the part 80a and inverting it, its end is fixed to the board 54 at SI, while the other end around which the pulley 11 is wound is attached to the pulley 13.
After the movable mirror unit 80 goes around the upper stage boob 914 on both wing parts and is reversed, the substrate 54 is moved in S2.
It is fixed at the top. That is, since the wire 15 is always maintained at a predetermined tension by the action of the tension lever 13a, when the pulley 11 rotates counterclockwise due to the operation of the stepping motor 10, the movable mirror unit is moved along with the carriage 40 by half the amount. ) 80 is the space 54 of the substrate 54
The exposure of the entire surface of the original 2 is inspected while moving to the left within the area a to satisfy the imaging conditions of the optical system. FIG. 1 shows a side sectional view of the optical system in the above reading device. The original m2 placed on the platen glass 1 is illuminated by a pair of fluorescent tubes 50 provided in a carriage 40 that moves on a slide rail. The optical image of the original 2 is reflected by the first mirror 7 provided integrally with the carriage 40 and the mirrors 9 and 9'' provided in a V-shape within the movable mirror unit 80, and is guided to the lens reading unit 20. The lens reading unit 20 includes an imaging lens 21, a color separation prism 22 provided behind it, and a solid-state imaging device C-cl+ccD 25,R provided at its imaging position.
-ah Consists of 2 CCDs. 1st mirror 7
, the light beams reflected and transmitted by the mirrors 9 and 9' are focused by the photographing lens 21 of the lens reading unit 20, and are converted into C
C-ch CCD separated into -ah image and R-ah image
25 and R-chccD27. pt.
Figure S2 (,) (b) shows an expanded plan view of the light beam incident on the lens reading unit 20 and a side view of the same incident light beam. y, the original surface of draft 2 is 2a%, the reflective surface on the optical axis of the first mirror 7 is 7a, and the reflective surfaces on the optical axis of mirrors 9, 9゛ are 9a, 9゛0
As shown in the figure, the luminous flux required to form an image on the light-receiving surface from the original 2 is the same as that of the solid-state image sensor C-c used in this embodiment.
The h CCD 25 and the R-cb CCD 27 are line sensors composed of pixel elements with a pixel width of approximately 7μ, and the imaging lens 21 has a focal length of 11F145.
1JI, pupil diameter is 11.2zy lens, reduction ratio 0.11
2, the document surface to be scanned has an extremely narrow rectangular shape, and each mirror also has a rectangular shape. The lens reading unit 20 is fixed by a mounting member to a photographic lens 21 housed in a lens barrel and a prism 22 provided with a guichroic mirror behind the photographic lens 21 that divides light into colors, and is further attached to the prism 22. Solid-state image sensor C-ah CCD 25 and R-chCCD 27
- is fixed. The method for attaching the light receiving elements to the prism 22 is as follows: C-Ch CCD 25 and CCD 25, each attached to a mounting adjustment jig that allows fine adjustment. J R-ahC
Measure the CD 27 optically and electrically using a synchroscope or the like, and move it to a predetermined position where there is no focus or image shift i1! ! It is fixed and integrated with the prism 22 by fixing means such as adhesive. In the present invention, the integrated prism 22 and C-c
The entire outer edges of the h CCD 25 and the R-cb CCD 27 are coated with a light shielding member 30f such as a black paint material. By doing this, the prism 22 and vC-
Unnecessary light from the outside that attempts to enter or enter the light receiving portions of the chCCD 25 and the R-eh CCD from the prism surface etc. can be completely blocked, and at the same time, internal reflection of the prism 22 can also be prevented. Note that for adhering the solid-state image sensor to the prism 22,
A two-component adhesive or an adhesive that is photocurable using ultraviolet light is useful, but such an adhesive may be mixed with the light shielding member 30, and the prism and CCD may be temporarily bonded with the adhesive when bonding the prism and CCD. After that, by applying an adhesive mixed with the light shielding member 30 and performing the main bonding, both the adhesive effect and the light shielding effect can be increased. Furthermore, by integrating the prism and CCD in this manner, a dustproof effect is also produced. Furthermore, the outer surface of the lens reading unit 20 is covered with a light-shielding case 60 that opens only the optical path portion, thereby further improving the light-shielding and dust-proofing effects.

【Effect of the invention】

According to the present invention, the prism and the solid-state imaging device are integrated by adhesive or other means, and the outer edge of the prism is coated with a light-shielding coating material, thereby eliminating the need for light to enter from the prism surface and enter the solid-state imaging element. It blocks light, prevents diffuse reflection within the prism, provides a dustproof effect, and provides a well-balanced reading device that can obtain good images with high contrast, especially in the case of color. became.

[Brief explanation of drawings]

ttS1 is a cross-sectional view of the optical system of the reading device according to the present invention,
Figures 2 (a) and (b) are a plan view and a side view of the developed optical path, Figures 3 (a) and (b) are a plan view and a side view of the Shin-X reading unit, and Figure 4 is a view of the reader unit. FIG. 5 is a block diagram of the provided image forming apparatus, and FIG. 5 is a perspective view of the reading device. 1...Platen glass 2...Original 7...First mirror 9,9゛...Mirror 20...Lens reading unit 21...Imaging lens:)::22...Prism 25-
C-cb CCD 27- R-ah CCD
30... Light shielding member 50... Fluorescent tube 60...
・Light blocking case

Claims (1)

[Claims] A light source that illuminates the original placed on the platen glass and a first
It consists of a carriage consisting of a mirror, a movable mirror unit consisting of two mirrors arranged in a V-shape, a fixed imaging lens, a light splitting prism and a solid-state imaging device installed behind it, In the reading device configured to form the original image on the solid-state image sensor, the light splitting prism and the solid-state image sensor are integrated, and an outer edge thereof is coated with a light-shielding coating member. reading device.