JPS6367860A - Reafder - Google Patents

Abstract

PURPOSE:To prevent solid-state image pickup elements from shifting in position from each other and to read an image stably against variation in temperature, a secular change, vibrations, a shock, etc., by fixing solid-state image pickup elements to a light splitting member through a fitting member equipped with an adjusting mechanism. CONSTITUTION:A couple of fixed plates P1 which have screw holes at symmetrical positions are adhered and fixed to both flanks of a prism 22 previously and movable plates 24a and 26b, and 24b and 26b which are supported by adhering the right and left end parts of the CCDs 25 and 27 are positioned slidably on the external surfaces of the plates. Long holes (e) along spectral optical axes A and B of the prism 22 are bored in the movable plates 24a and 26a, and 24b and 26b, and a couple of screws (s) are inserted threadably into the screw holes of the fixed plate P1 through the long holes (e) from right and left. The movable plates are moved in the optical-axis directions to adjust the positions and then the screws (s) are clamped to fix the plates, thereby uniting them to the prism 22. Further, the movable plates are adhered to the fixed plates to reinforce the fixation.

Description

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

The present invention relates to an image forming apparatus such as a facsimile machine, a copying machine, a printer, and an image capturing apparatus such as a television camera (two-reading apparatus). using CC
The present invention relates to a reading device equipped with an image reading section that reads an optical image using a solid-state image sensor such as D.

BACKGROUND OF THE INVENTION For example, a color image forming apparatus, particularly a digital color image forming apparatus, generally includes a color image processing apparatus such as an image reading section and an image writing section. In the image reading section, for example, an optical image of the document surface obtained by exposure scanning is passed through a reading imaging lens system and separated into a plurality of lights by a light splitting means behind the imaging lens system. C
)zg-, and then images are formed on a line image sensor consisting of a solid-state image sensor that receives light in each channel, each line image sensor uses the light ( The axial position and perpendicularity of each spectral optical axis must be sufficiently adjusted and installed so that ↑ can be imaged correctly.In other words, each line image sensor optical image must be aligned as accurately as possible with respect to each other. If they do not match, the reproduced image reproduced by the writing section will be adversely affected.The solid-state image sensor (
For example, line image sensor Toshiba TCD 106C)
Since each pixel is composed of an array of 1i7ii fibers of approximately 7 μl, if the correspondence of the light images incident on the image sensor exceeds approximately 174 pixels (approximately 2 μl) in the embodiment shown in FIG. 1, which will be described later, the reproduced image For example, color ghosts of red, blue, etc. may appear around the edges of black letters and figures as fringes. This effect becomes particularly noticeable when a deviation of one pixel (approximately 7 μl) or more occurs in the above-mentioned correspondence. Electrical correction is generally performed to prevent this color ghost. However, if most of the color ghosts are removed by electrical processing, the memory capacity required would be extremely large, and inconsistencies such as variations in line thickness would occur in the image, resulting in technical difficulties. Due to the difficulties involved, it cannot be said to be perfect, and from the perspective of commercialization, it can be said that it has not been finalized. The present applicant has made a proposal in Japanese Patent Application No. 60-239174 as a means for preventing pixel misalignment between image sensors. In this proposal, as shown in FIG. 12, each solid-state image sensing device 51a, 51b is connected to a base 52a. 52b to form a unit, and as shown in Figure ttS9, the unit can be adjusted in two spatially orthogonal X and Y axes including the optical axis direction and in the rotational direction of the X+Y sleeves, It is designed to be mechanically adjusted and installed. The above proposal allows fine adjustment after mounting each solid-state image pickup device, and immediately after adjustment, the correspondence between each device is almost the same. However, as shown in FIG. 11, the light splitting prism 54, which is an optical member provided behind the condensing lens 53, and the solid-state image sensor 51a
, 51b are each attached to a frame, and a number of holding members, such as supporting parts, are adjusted and attached to the frame using adjustment screws, and these members resist heat, expansion and contraction due to temperature changes, and Misalignment is likely to occur due to factors such as poor adjustment, looseness and errors in the screw itself, and it has not been easy to resolve pixel misalignment, including the issue of restorability. In particular, when holding and fixing a solid-state image sensor using an M-tight screw, which is a special feature of photography, it is necessary to tighten the solid-state image sensor with the screw and fine-tune it on the micron order, which requires extremely precise work. Have difficulty. Furthermore, even if the solid-state imaging device is set up in a jig quite firmly, the final tightening of screws, etc. will be due to the torque, and if it is removed from the jig after tightening, it may move more than a few micrometers due to return of distortion, etc. many, also for example 1
Even if the parts are placed accurately within μR, due to stress and strain inside the parts, it is recognized that deviations of several μ1 or more may occur during impact tests, etc., and furthermore, the coefficient of thermal expansion of the supporting member, etc. Due to this, there were some gaps in the temperature test results that caused installation errors. In addition, in order to fix the solid-state image sensor,
#70: There is a proposal to fix using attachment 1, but this proposal is about fixing a single solid-state image sensor, and is not about fixing force, optical member, etc.
1'7.1 gJ with a light i- on the frame
This method is intended to be fixed by filling an adhesive with the adjustment amount, and is suitable for image reading that requires high precision holding without positional deviation using multiple image sensors. It was not applicable. [Problems to be Solved by the Invention] A color image processing device, particularly a prism forming a part of an optical member, a combination device of the prism and a lens, a light splitting means using a prism and a semi-transparent mirror, or a prism and a semi-transparent mirror. In a color image reading device, a plurality of solid-state image sensors are arranged at the imaging position of a device such as a combination of mirrors and lenses, and each solid-state image sensor reads the image formed by each solid-state image sensor and performs signal processing. It is required that the images formed by the elements correspond exactly to each other. SUMMARY OF THE INVENTION An object of the present invention is to provide a color image reading device that prevents misalignment of solid-state image sensors and provides the most stable image reading under all conditions such as temperature fluctuations, changes over time, vibrations, and shocks. shall be.

[Means to solve the problem]

The above purpose is to fix the solid-state image sensor to the light splitting member via a mounting member equipped with an adjustment mechanism in a reading device that reads an optical image using several solid-state image sensors installed behind the light splitting member. This is achieved by a reading device characterized by the following.

【Example】

An image forming apparatus equipped with a color image reading device of the present invention will be explained with reference to FIG. In the figure, ^ is an image reading device with a reading section, B is a writing unit,
C is an image forming section and constitutes a color image processing device, and D is a paper feeding section. In the image forming apparatus 8, 1 is a platen glass, and an original 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. The movable mirror unit 8 is provided with mirrors 9 and 9', and the slide rail 3
In combination with the first mirror 7 provided on the carriage 4, the optical image of the document 2 on the flatten glass 1 is guided to the lens reading section 20.The carriage 4 and the movable mirror unit 8 is driven by a stepping motor 10 via a wire 15;
They are driven in the same direction at a speed of hv and h/2V, respectively. There are standard white plates 16 on the back side of both ends of the platen plus 1.
17 is provided so that a standard white signal can be obtained before the start of original reading scanning and after the end of scanning! & has been. Lens reading (22) 20 includes a lens 21 as a reading lens system, a prism 22 as a 1% light component, a red channel (hereinafter referred to as R-ch) CCD 25 as a line image sensor of a solid-state image sensor, and a cyan channel (hereinafter referred to as R-ch) CCD 25. It is composed of a CCD 27 (referred to as C-eb). The original light image transmitted by the first mirror 7, mirror 9, and mirror 9' is focused by the lens 7:21, and is converted into an R-cb image and a C-cb image by the guichroic mirror provided in the prism 22. The R-Ch CCD 25 and the C-el I are separated and each optical image is fixed to a prism 22 forming a part of the optical member via mounting members 24 and 26.
The images are respectively formed on the light receiving surface of the CCD 27. The fluorescent lamps 5 and 6 are commercially available warm white fluorescent lamps in order to prevent the emphasis and placement of specific colors based on the light source when reading a color document, and 40cm fluorescent lamps are used to prevent flickering.
It is turned on by a high-frequency power source of K If z, and is kept warm by a heater using Bonosta to maintain a constant temperature of the tube wall or to promote ohm-up. The image signals output from the R-ch CCD 25 and C-ch CCD 27 are processed through a signal processing section (not shown), and color signals separated according to the toner color are output and input to the writing unit 8. Then, images by each laser beam generated by a semiconductor laser are sequentially projected onto the circumferential surface of the photoreceptor drum 31, and for each projection, images are developed by developing rollers r, n, and m+2, respectively, and three colors are developed. A color image is formed using toner. 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 and ejected to the outside of the apparatus via a fixing device 33. Then, the color image reproduction ends. FIG. 2 shows a first embodiment of a mounting structure for an image sensor according to the present invention incorporated into the lens reading unit 20. As shown in FIG. 21 is a lens of a reading lens system attached to a support member 21a and fixed on the device board; 22 is the lens 21;
A prism is fixed to the supporting member 21a by a holding member 22a behind the prism 22, and the prism 22 converts the original optical image focused by the lens 21 into a R-elI image using a guichroic mirror 23 provided inside the prism 22. Ah
A line image sensor R-ch CC is separated into C-cb image spectral B and is fixed to a prism 22, which is a light splitting member, with position adjustment via mounting members 24 and 26.
The lens system is configured to form images on the light receiving surfaces of D25 and C-elI CCD 27, respectively. The mounting member 2 used in the 6y”t=taking device of the present invention
4゜26 is equipped with an adjustment mechanism consisting of a fixed plate as shown in Fig. 2 and a movable plate that slides on the fixed plate and can be fixed at any position. The optical axis direction of the light image received by the light beam can be freely adjusted and fixed at a position where a predetermined light image is correctly formed. FIG. 3 shows the configuration of the mounting member 24 (26), in which a pair of fixing plates P1 having screw holes are adhesively fixed in advance at symmetrical positions on both sides of the prism 22, and the CCD 25 is attached to the outer surface of the fixing plates P1. (27) are slidably sandwiched between movable plates 24a (26a) and 24b (26b) whose left and right ends are bonded and supported. Each of the movable plates 24a (26a) and 24b (26b)
are provided with elongated holes e along the directions of the spectral optical axes A and B of the prism 22, respectively, so that a pair of screws S can be screwed into the screw holes of the fixed plate P1 from the left and right through the elongated holes e. By tightening the screws S, each CCD and prism 22 can be fixed and integrated. That is, each CCD is illuminated on the prism 22 and mounted in a permanently fixed state, and then each movable plate is moved in the optical axis direction for each spectroscopic sleeve A or B to adjust its position, and then the screw S is adjusted. Although it is fixed by tightening and integrated with the prism 22, it is also possible to further strengthen the fixation by adhering it to the movable plate and the fixed plate. FIG. 4 shows how the movable plates 24a and 24b (24a and 2413), which are symmetrically attached to both sides of the prism 22, are made into one part! This shows the #1 member, in which a CCf125 (27) is attached in advance by adhesive to the inside of the bridge-shaped movable member 24c (26c), and a pair of CCf125 (27) are attached through the elongated hole e as in the case in Fig. 3. screw S
It is fixed to the fixing plate P1 after adjusting the position. In all of the above embodiments, the CC[)25(2)) is attached to the arm-shaped attachment parts on both sides of the CC[25(2)]. - side must be 'I! ! You can wear it, but the other sides are not necessarily V.
Therefore, the preferred method of attachment is to use - number of attachment members to attach to the attachment portion on the - side in terms of adhesion or adhesion. FIG. 5 shows an example in which the CCD is adjusted and fixed by a cantilevered movable plate, and the movable CCD 24d (26d), on which the CCD is fixed in advance by adhesive, is adhesively fixed to one side of the prism 22. This is an example in which the fixing plate P1 is adjusted and fixed. Furthermore, in the above embodiment, each CCD is fixed to the imaging section by its respective fixing plate P1, but in FIG. CCD25 and CCD27 can be glued and fixed to fixed plate P2! lJJ provisional 24
This is an example in which e (26e) is adjusted and fixed. The material of the mounting members 24 and 28 is # for two reasons.
A material with a small X expansion coefficient is desired. One is to prevent pixel misalignment due to temperature fluctuations, and the other is to prevent internal distortion of the mounting member glued to the prism due to the difference in #l expansion coefficient between the two, which may cause cracks in the prism. This is to prevent this from happening. Above temperature *
The problem of pixel misalignment due to gJ + l2 can be reduced by making the fixing conditions of each CCD with the mounting part members exactly the same, but the linear expansion coefficient needs to be smaller. There is. The linear expansion coefficient of a normal prism is 7.
, 1X1O-6 (-7 for the optical glass opening), so glass or ceramic materials (7,0
~8.4
1ox 10-') etc. are suitable, and aluminum material (2
5×10−′) is not very suitable. The present inventors conducted tests using various materials as mounting members, but no image shift due to thermal expansion was detected when glass materials, other ceramic materials, and low thermal expansion alloys were used. In the above example,

[Music and mounting parts, mounting parts and CC]
Adhesive was used to fix it to D, and after adjusting the relative position of each CCD for the divided optical image, rtIJ3
In the figure, it is shown to be tightly fixed using adhesive. In particular, in Fig. 3, even if iron (12 x 10-') with a large #l expansion coefficient is used as the mounting member, the dimension in the a direction is short in practical terms, so it does not elongate much due to heat.
The other direction is the direction in which the line sensors are arranged, and since the prism material and the pankeno material of the line sensor are ceramic materials, their coefficients of linear expansion are almost the same, so no pixel misalignment occurred with this configuration. . The present inventors conducted comparative studies using many available adhesives. As a result, it was concluded that among two-component type adhesives and light-curing adhesives, especially ultraviolet-curing adhesives are most preferable as adhesives to be used in the present invention. - reached. Adhesives include epoxy and acrylic adhesives, and are further divided into one-component types and two-component types. One-component type products usually have a hardening agent mixed into them during manufacture, and when used, they gradually harden and dry when exposed to air, etc., and harden, resulting in long curing times, and the degree of curing and shrinkage during curing. Due to the irregularity of the surface, etc., it is necessary to use special equipment for adhesive fixation. Therefore, it is not suitable from the viewpoint of the purpose of use and productivity of the present invention. In this regard, the two-component type and immediate-acting type cures in a few minutes at most by kneading the curing agent and the main ingredient during bonding, shortening the curing time.
This stabilizes the degree of curing and is effectively suitable for this purpose. In addition, there is a one-component cyanoacrylate 'R8% type that is quick-acting, but it does not adhere well on impact.
However, this is not necessarily a preferred form of application since the adhered object may be deformed due to shrinkage of the adhesive when it dries. The present inventors used Hardlock E510K (trade name) as a two-component type adhesive and performed bonding at room temperature, and were able to obtain good results in environmental tests, etc., which will be described later. During the above bonding process, attempts were made to shorten the bonding time by deliberately changing the temperature conditions, but as a result, rs element deviation during bonding was observed, albeit slightly.
It became clear that this was not desirable. On the other hand, photocurable adhesives can speed up the curing time of the adhesive simply by changing the intensity of light, improving workability, reducing costs, and stabilizing the product. Among photo-curable adhesives, ultraviolet-curable adhesives in particular have almost no change in heat even when exposed to ultraviolet rays, and can provide stable effects. The present inventors used ThreeBond TB30 as a photocurable adhesive.
60D (product name), Denka 1045K (product name), Norland 65 (product name), etc., were bonded in a short time by irradiating ultraviolet light with a high-pressure mercury lamp. I was able to get results. Furthermore, using UV-curable urethane-based ThreeBond 3062B (trade name), LT350 (trade name), etc., it was possible to obtain an adhesive that was even more effective in moisture resistance and had guaranteed strength. Although glass, ceramic materials, etc. are used as the mounting member, it is particularly effective when used in combination with a material that has good ultraviolet transmittance, as it allows for more rapid curing. Prism 22 of CCD 25 and CCD 27 according to the invention
For adjustment and fixing, prepare a mounting jig TC in advance. While gripping the side surfaces of the CCD 25 and CCD 2 respectively, the mounting jig is used for each optical axis of the spectral ^ and spectral B as shown in Fig. tjS10, and the x perpendicular to the optical axis as shown in Fig. 9. It is possible to adjust the two directions of y and the rotational direction regarding the Xu/axis, and the adjustment is made so that there is no pixel shift by fine adjustment of the mounting jig TC. The striped chart image provided at the original position is captured on CCD25 and C
An image is formed on the CD 27, and its output signal is recorded in a superimposed manner on a synchroscope. If the black and white stripe spacing is set based on the designed reduction magnification of the condenser lens and the size of the CCD pixel, and a chart corresponding to one stripe power arch pixel is created, it will be possible to obtain a chart from the recorded signal superimposed on the synchroscope. The amount of pixel shift can be easily read. For example, synchronoscope C shown in FIG.
The RT plane exemplifies a situation where there is a pixel shift between the CCD 25 and the CCD 27. In addition, by adjusting the mounting jig TC while checking with a synchroscope, it is possible to find the relative position between the CCDs without pixel shift, and at this position, the CCD 25 and CCD 27 are attached to the prism surface of the prism 22 using the screws S. It is fixedly installed at the imaging position via the mounting member 24 (26). The image reading section has a plurality of solid-state image sensors fixed to a prism, which is a light splitting member, using an adhesive corresponding to FIG. 6 via a mounting member made of a ceramic material, and a mechanical structure shown in FIG. 12. Various comparison tests were conducted on the image reading section that holds a solid-state image sensor. The test was conducted by placing the knitted chart at the original position and superimposing output signals from a plurality of attached solid-state image sensors using a synchroscope and comparing them, paying particular attention to pixel misalignment. (1) Vibration resistance test A vibration resistance test with variable frequency was conducted for 30 minutes, and the state of pixel misalignment before and after was compared. Among those with a fi machine structure, sagging of the vertical part occurs (I).A pixel shift equivalent to about 4 pixels (30 μml) was observed.No pixel shift was observed in the case of this example. (2) Impact test) Perform a drop test at 40°C,
A comparison of the pixel misalignment before and after was made, and it was found that the pixel misalignment was equivalent to about 3 pixels (20 μm) due to the mechanical structure. No pixel shift was observed in the case of this example. (3) Temperature test First, the ambient temperature was set to 20℃ after opening for 2 hours.
℃ to 70℃ and compared the situation of pixel misalignment. In the case of mechanical structure, a pixel shift equivalent to about 4 pixels (30μ shoulder) was observed. Then the temperature dropped from 70'C to 2 in 2 hours.
The ambient temperature was restored to 0°C. Even in the restored state, it was observed that a pixel shift equivalent to about 2 pixels (15 μm) remained due to the mechanical structure. - No pixel shift was observed from beginning to end in the power factor example. As is clear from the above description, in the present invention, a CCD is fixedly mounted on a prism via a mounting member made up of a fixed plate and a movable plate. As shown in the figure (if the configuration is such that it can be adjusted by sliding in the direction of the spectral optical axis by groove fitting, each CCD fixed to the movable plate will be moved with its light-receiving surface always facing the optical axis. There is a point f1 that makes it easy to adjust the image formation position.In addition, in the above embodiment, each fixing plate PL with respect to the prism,
P2. We explained the excellent effects of all methods of fixing I'3, particularly adhesives using specific adhesives. However, the fixing means is not limited to this. For example, as shown in FIG. 8, the prism 22 is sandwiched from both sides by two fixed plates P4 made of a low thermal expansion alloy, and is fixed by tightening with screw members 29. In this embodiment, there is internal stress in the CCD 25 (27) and other members due to tightening, and there is a deficiency α that is likely to change over time, but on the other hand, the CCD can be easily removed and replaced. Further, as shown in FIG. 11 of the embodiment, a dustproof backing P configured to cover all the elements of the CCD is attached between the prism 22 surface and the CCD 25 (27), and the dustproof backing P is attached to the mounting member 24a.
, 24b should be fixed to the inner surface (fixed guide piece 24c,
24d. In this case, it will be more stable if the contact surfaces of the dustproof backing P and the mounting members 24a and 24b are fixed with an adhesive. If a dustproof panking PC is installed as described above, the prism 22 and CCD 25 (27
), for example, toner of the recording developer or paper dust of the recording paper does not adhere, and the image is stable for a long period of time. Furthermore, although the described embodiments all use a prism as the light splitting member, the light splitting member is not limited to a guichroic prism, and the color separation filter and the member may be ND.
The same applies to combinations of filters, etc. [Effects of the invention] As with this disease, the disease has been cured! When fixing an optical member, such as a light splitting member and a solid-state image pickup device, at an imaging position via a mounting member provided with blue light, many factors that cause pixel misalignment are removed, and thus A clear and excellent color image can be reproduced and obtained by the color image reading device of the present invention, and there is no deterioration in image quality due to the pixel misalignment even with changes in the environment or the passage of time.
), there is no need for complex electrical correction circuits for the pixel misalignment and color ghost correction, and there is an effect of excellent durability. In addition, as explained in the examples, the present invention uses filling adhesive, but since it uses a method similar to close contact adhesive, shrinkage when the adhesive hardens is smaller than in the case of commonly used filling adhesive. It is possible to obtain an apparatus that can perform stable image reading with extremely high accuracy without occurrence of such problems.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram 6 of a color image forming apparatus equipped with a color image reading device of the present invention. FIG. 152, FIG. 3, FIG. 5, FIG. 6, FIG. 7, and FIG. An explanatory view showing an example of a fixed state. FIG. 4 is a perspective view showing one example of the mounting member. FIG. 9 is a perspective view showing the adjustment direction of the line image sensor. FIG. 10 is an explanatory diagram of a method for adjusting the position of a solid-state image sensor according to the present invention. FIG. 11 is a perspective view in which a dustproof member is installed between the prism and the solid-state image sensor. FIG. 12 is a sectional view showing the mounting structure of a conventional line image sensor. 21... Lens barrel 22... Prism 24
(26) Mounting member 25 (27) -R-cl+(C-ah) CCD (solid-state image sensor) P1tP2tp3+p4... Fixing plate 24a (26a), 24b (26b), 24e (26c)
), 24d (26d), 24e (26e), 24f (
26r), 24g (26g) - Movable plate applicant Konishi Roku Photo Industry Co., Ltd. Figure 5 Figure 6 Figure 7 (a) (b) zl Bij;'2)'J No. 8
Figure (a) (b) 25g P4 P4 Figure 9 Figure 10

Claims (5)

[Claims] (1) In a reading device that reads an optical image using a plurality of solid-state image sensors provided behind a light splitting member, the light splitting member is fixed to the solid-state image sensor via a mounting member provided with an adjustment mechanism. Characteristic reading device. (2) The reading device according to claim 1, wherein an adhesive is used for said fixing. (3) The reading device according to claim 2, wherein the adhesive is a two-component type adhesive. (4) The reading device according to claim 2, wherein the adhesive is a photocurable adhesive. (5) The reading device according to claim 4, wherein the photocurable adhesive is an ultraviolet curable adhesive.