JPH01126868A - Reader - Google Patents

Abstract

PURPOSE:To eliminate the deterioration in picture quality based on deviation of a picture element by using a couple of mount members delivering heat uniformly to both side faces of an optical split member of a read unit to fix each solid-state image pickup element. CONSTITUTION:Mount members 24, 26 are a couple of support members fitted to both side faces of a prism 22, an adhesives is used to adhere the one end to the side face of the prism 22 and the other end is fixed with a solid-state image pickup element (CCD) 25 or CCD 27 to fix each photodetection face to an image forming position constituted by an image forming lens and the prism 22. Then a material and dimension are selected for the mount members 24, 26 so as to make the product between the heat conductivity and the cross sectional area identical, and the heat generation of the CCDs 25, 27 is dissipated uniformly from both ends to the prism 22. Thus, the position deviation of the solid-state image pickup elements is prevented and stable picture reading is attained.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a reading device for reading images of image forming devices such as facsimiles, copiers, and printers, and imaging devices such as television cameras. Using an optical member such as a dichroic prism, the original image is COD
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 the above.

[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. The image reading section passes the light image of the document surface obtained by exposure scanning, for example, through a reading imaging lens system and separates it into a plurality of lights using a light splitting means behind it.
) etc., and then images are formed on a line image sensor consisting of a solid-state image sensor that receives light in each channel. The axial position and perpendicularity of each spectral optical axis must be adjusted sufficiently to ensure proper image formation. That is, unless the optical images of each line image sensor are made to match each other as accurately as possible, the reproduced image reproduced by the writing section will be adversely affected. The solid-state image sensor, for example, the line image sensor TCD 106C manufactured by Tohoku, is composed of an array of pixels with each pixel being about 7 μm, so in the example shown in FIG. If it exceeds 1/4 pixel (approximately 2 μm), color ghosts of other colors, such as red and blue, will appear as fringe on the periphery of the reproduced image, for example, on the periphery of black characters and figures. This effect becomes particularly noticeable when a deviation of one pixel (approximately 7 μm) 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 required memory capacity will be extremely large, and problems will occur in the image, such as changes in line thickness, resulting in technical difficulties. Therefore, it cannot be said to be perfect, and it can be said that it is unresolved from a commercialization perspective.

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. 11, each solid-state image sensor 51a, 51b is connected to a base 52a.

52b to form a unit, and as shown in FIG.
It is possible to adjust the direction of rotation in the two axis directions of +V and the X+V axis, and the adjustment and installation are performed mechanically. The above proposal allows for fine adjustment of the mounting of each solid-state image sensor, and immediately after adjustment, the correspondence between the elements almost matches each other. However, as shown in FIG.
1a and 51b are each attached to a frame, and in between, many holding members, such as supporting parts, are adjusted and attached with adjustment screws, and these members are subject to thermal expansion and contraction due to temperature changes, and incorrect adjustment of the screws. , misalignment between multiple elements is likely to occur due to play and errors in the screw itself, or misalignment between multiple elements due to optical aberrations in optical members, and it is not easy to eliminate pixel misalignment, including restoration. Ta. In particular, when holding and fixing a solid-state imaging device using precision screws, which have a mechanical structure, it is necessary to tighten the solid-state imaging device using the screws and perform fine adjustment work on the micron order, making it extremely difficult to achieve precision. . 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 set accurately within μm, there is stress strain inside the parts, so impact tests etc.
It has been recognized that the above-mentioned deviation occurs, and furthermore, there is a drawback that the thermal expansion coefficient of the supporting member causes an installation error in the temperature test result.

In addition, in order to fix the solid-state image sensor,
There is also a proposal for fixing using an adhesive according to No. 70, but this proposal is about fixing a single solid-state image sensor, and is not about fixing the solid-state image sensor to an optical member. It is intended to be adjusted and fixed.
Fixation is performed by filling the adjustment amount into adhesive, and it is not applicable to image reading that requires high precision holding without positional deviation using multiple image sensors. Ta.

[Problem that the invention seeks to solve]

There is a need to provide a high-resolution reading device for a color image processing device, particularly a color image reading device in which a plurality of solid-state imaging devices are arranged and the image formed by each solid-state imaging device is read and signal processing is performed. Further, it is required that the images formed by each solid-state image sensor correspond to each other accurately. The present invention prevents misalignment of solid-state image sensors, and is able to withstand all conditions such as internal temperature, especially temperature fluctuations due to temperature rise or fall due to heat generation from solid-state image sensors, changes over time, vibrations, and shocks. It is an object of the present invention to provide a color image reading device that can perform the most stable image reading.

[Structure of the invention]

The above object is to provide a reading device in which a solid-state image sensor is provided at an image-forming position of an optical system including an imaging lens and a light splitting member and is fixed to the light splitting member with an adhesive via a mounting member. This is achieved by a reading device characterized in that it is provided with a mounting member that equalizes heat propagation from both sides to the light splitting member.

〔Example〕

First, 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, A is an image reading device having a reading section, B is a writing unit, C is an image forming section which constitutes a color image processing device, and D is a paper feeding section.

In the image reading device A, ``■'' is a platen glass, and the original 2 is placed on this platen glass l.

The document 2 is carried by a carriage 4 that moves on a slide rail 3.
It is illuminated by fluorescent lamps 5 and 6 installed in the area. The movable mirror unit 8 is provided with mirrors 9 and 9', which move on the slide rail 3, and in combination with the first mirror 7 provided on the carriage 4 read the optical image of the document 2 on the platen glass l with a lens. Derived to unit 20.

The carriage 4 and the movable mirror unit 8 are driven by pulleys 11, 12, 13, and 141m, which are driven by a stepping motor IO via a wire 15, to receive V and l/l, respectively.
They are driven in the same direction at a speed of 2V. 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 a standard white signal can be obtained before the document reading scan starts and after the scan ends.

The lens reading unit 20 includes a lens barrel 21 housing an imaging lens as a reading lens system =7-, a prism 22 as a light decomposition means, and a red channel (hereinafter referred to as R-ch) as a line image sensor of a solid-state image sensor. It consists of a CCD 25 and a cyan channel (hereinafter referred to as C-ch) CCD 27. The first mirror 7 and the mirror ichroic mirror separate the light into an R-Ch image and a C-Ch image.
R-ah CCD25 and C-Ch C fixed to 2
The images are respectively formed on the light receiving surface of the CD 27.

The fluorescent lamps 5 and 6 are commercially available warm white fluorescent lamps used to prevent emphasis or attenuation of specific colors based on the light source when reading color documents, and 40K fluorescent lamps are used to prevent flickering.
It is lit by a high frequency power source of Hz and is kept warm by a heater using a POSISTOR to maintain a constant temperature of the tube wall or to promote warm-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 colors are output and input to the writing unit B. Then, images by each laser beam generated by a semiconductor laser are sequentially projected onto the circumferential surface of the photoreceptor drum 31, and after each projection, three-color toner is developed by developing rollers I, II, and III. to form a color image.

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. , to finish copying the color image.

The configuration of the lens reading unit 20 in the reading device A, that is, the lens barrel 21. Fixation of R-ch CCD 25 and C-ch CCD 27 to the prism 22,
The holding is performed as follows.

As shown in FIG. 2(a), the lens barrel 21 is housed in a V-shaped receiver opening perpendicularly upward to the lens holding member 21a, and is secured by a fastener 21c serving as a lens barrel supporting member. After being fixed, it can be attached to a predetermined position on the device board 40.

In this embodiment, a mounting surface 21b to which the front surface of the prism 22 can be joined is formed on the rear end surface of the lens barrel 2I, and the prism 22 can be fixed to the mounting surface 21b by adhesive. It has become.

Since the mounting surface 21b is formed by a simple turning process, the distance to the imaging lens housed in the lens barrel 21 and the perpendicularity to the optical axis are extremely accurate, and the prism 22 attached to it has extremely high accuracy. As mentioned above:
A predetermined optical image can be accurately formed on the light receiving surfaces of the R-ch CCD 25 and the C-ch CCD 27 without being affected by optical aberrations.

As shown in FIG. 2(b), the amount of deviation (
The right angle RLXRL' of the prism surface to the lens optical axis (7
) The amount of skew) can be checked using the synchroscope shown in FIG. The check procedure will be described later.

As shown in the CRT display of FIG. 7, if the respective levels of the black line portion and the white line portion with respect to the white background are P and Q, the MTF is determined by the following equation.

The higher the MTF value, the better the resolution. 1 MTF value of 30%, which is the standard for the influence of the amount of deviation in resolution.
As an example, when the amount of inclination is about 10 minutes in angle, the MTF value is 21%, which is a decrease of about 9%.
Furthermore, when the amount of inclination becomes about 30 minutes, the MTF value increases to 15%.
This represents a decrease rate of approximately 50%. Since this will interfere with the extraction of black and white discrimination signals, by maintaining this surface precision and fixing the lens barrel 21 and prism 22 together in advance, a drop in the defective rate in the later stages of production can be prevented. However, not only is there a cost advantage, but the influence of the material of the lens holding member 21a, the mounting member 24, etc. on pixel misalignment after COD mounting is also reduced, and further effects are exhibited.

In addition to the adhesive method described above, the prism 22 can be fixed by using a prism holding member 22b in close contact with the mounting surface 21b using the mounting screws 23 as shown in FIG. 2(c). There is also. These methods of fixing the prism 22 are applied to each embodiment described below.

For adhesion of the prism 22 to the lens barrel 21, an adhesive that can withstand various environmental tests in addition to adhesion is selected and used. In this embodiment, the CCD 25 and Since the same adhesive is used for bonding the CCDs 25 and 27, the characteristics of the adhesive will be summarized in the section explaining the fixing of the CCDs 25 and 27.

The following two methods have been proposed for adhering the CCDs 25 and 27 to the prism 22. The first method is to attach the CCDs 25 and 27 to the prism 22, as shown in FIGS. 2(a) and 2(C). and a method of fixing with adhesive over 2G.

The mounting members 24 and 26 are a pair of supporting members that are mounted on both sides of the prism 22, and one end of the mounting members 24 and 26 is attached with adhesive as shown in FIG. is fixed to the side surface of the plate 12- rhythm 22, and C0D25 or C is attached to the other end.
The CD 27 is fixed and supported, and the light receiving surface is fixed at the imaging position of the optical system constituted by the imaging lens and the prism 22.

In the present invention, the pair of mounting members 24a (26a) and 24b (26b) and the mounting members 24c (26c) and 24
d (26d) are configured to have uniform heat propagation characteristics, and furthermore, each of the prisms 22
The center of each pixel row is aligned with the optical axis c-c' of the optical system.

That is, the mounting members 24a (26a) and 24b (2
6b), and the mounting members 24c (26c) and 24d (
26d), materials and dimensions are selected such that the product of thermal conductivity η and cross-sectional area A is the same, so that the amount of heat generated by each COD is equally transmitted to the prism 22 from both ends thereof. It is constructed so that it can be dissipated.

As mentioned above, each mounting member is assumed to form a pair, and the temperature conditions at the mounting position, that is, each C
Depending on the calorific value of OD or the distribution difference in internal temperature,
Different shapes and dimensions should be used for D, and it is of course possible to use mounting members other than those shown in FIGS. 3 and 4.

Therefore, the present invention prevents the occurrence of pixel misalignment due to the elongation of the ceramic package due to self-heating during the driving state of each COD or an increase in the internal temperature of the device surrounding it. prism 2
2, bending stress resistance, durability against repeated stress due to expansion and contraction such as elongation or contraction when restoring to an unused state, fatigue resistance, durability of bonded parts, etc., and each COD.
In order to ensure uniform elongation in consideration of heat transfer from the base to the base, a homogeneous material, preferably a low thermal expansion material such as an Invar alloy, is commonly used. Also, the above example
Each COD is fixed to the imaging section using its own mounting member, and FIG. 5(a) shows a second method in which the mounting member 24b is attached to the prism 22 using a common mounting member 24b. Glue and fix the mounting member 24b
A CCD 25 and a CCD 27 are respectively glued and fixed to the holder.

As for the material of the mounting member, a material with a small coefficient of linear expansion is desired for two reasons. One is to prevent pixel shift from occurring due to temperature fluctuations, as mentioned above.
The other purpose is to prevent the prism from cracking due to internal strain caused by the difference in coefficient of linear expansion of the mounting member bonded to the prism. The above-mentioned problem of pixel misalignment due to temperature fluctuations can be reduced by making the fixing conditions of each COD to the mounting member exactly the same.

In addition, as for the materials used for each of the above-mentioned mounting members, since the linear expansion coefficient of a prism is usually as small as 7.4X 1O-6 (optical glass BK-7), glass or ceramic materials (7.4X 1O-6) are recommended for the mounting members. ~8.4X 1O-6) and low thermal expansion alloys (e.g. Invar alloy (1~3X 1O-6)
6), Niresist cast iron (4-IOX to-6)), etc. are suitable, and aluminum material (25X 1O-6) is not so suitable.

The 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 (Invar alloys) were used. Ta.

In the above embodiment, the prism and the mounting member, the mounting member and the CO
Adhesive was used to fix COD to D, and after adjusting the relative position of each COD for the divided optical images, in FIGS. 3 and 4, adhesive was used to fix the COD in close contact. In particular, in Fig. 3(d), even if iron (12 x 10-') with a large coefficient of linear expansion is used as the mounting member, the elongation due to heat is not affected much because the dimension in the a direction is short in practical terms, and the elongation in the direction is the direction in which the line sensors are arranged, and since the prism material and the package material of the line sensor are ceramic materials, their coefficients of linear expansion are approximately the same, and with this configuration, no pixel misalignment occurred.

The present inventors conducted comparative studies using many available adhesives. As a result, it was concluded that among two-component type adhesives and photocurable adhesives, especially ultraviolet curable adhesives are most preferable as adhesives to be used in the present invention.

Adhesives include epoxy and acrylic adhesives, and are further divided into one-liquid type and two-liquid type. 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. There are liquid-based cyanoacrylate-based products that are quick-acting, but the adhesive may peel off during impact.
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 E51 as a two-component type adhesive.
When bonding was carried out at room temperature using 0K (trade name), good results were obtained in environmental tests, etc., which will be described later. At the time of bonding, an attempt was made to significantly change the temperature conditions to shorten the bonding time, but as a result, pixel misalignment during bonding was observed, albeit slightly, and 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 Threepond TB30 as a photocurable adhesive.
60B (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 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. In the adhesive bonding method described above, the opposing surfaces of the adhesive members of each part are pressed together, and a small amount of adhesive is extruded from the sides of the pressed surfaces using an appropriate extrusion means. Since the adhesive has fluidity, it flows into the slight gap created between the pressing surfaces and firmly fixes the adhesive members to each other. The bonding method may be such that the adhesive is extruded so as to adhere to the entire surface of the opposing surface of the bonding member, and may flow into the gap. Alternatively, the adhesive may be introduced at appropriate intervals. Further, if the device is capable of arranging the adhesive members with appropriate positional accuracy, the adhesive may be applied in advance to the adhesive surface of each adhesive member in spots or areas, and the adhesive surfaces of the adhesive members may be immediately pressed and bonded.

A preferred embodiment of the bonding method will now be described. Figure 5(b) and Figure 5(c) are C in Figure 5(a).
CD25, ccD27 and their common mounting member 24
b. When bonding the mounting member 24b to the prism 22 shown in FIG. 5(a), after fixing the mounting member 24b to a predetermined position on the prism 22, apply adhesive to the end of the mounting member 24b as shown in FIG. 5(b). One possible method is to pot it and allow it to penetrate into the mounting surface.

In this case, a light-curing adhesive is used as the adhesive, and the mounting member 24
By using a light-transmitting substance as e, the use of a photocurable adhesive becomes more effective. That is, by utilizing transmitted light to harden the adhesive that has become thinner inside due to penetration during the end botting, it is possible to accelerate the hardening of the adhesive. Furthermore, as shown in FIG. 5(c), the mounting member 2
4b or a general adhesive method in which adhesive is dropped on the surface of the mating member facing the prism 22 and the two are pressed together, the adhesion of the adhesive is as shown in FIG. 5(b) using the botting method. By using a light-curing adhesive and a light-transmitting mounting member 24e, in addition to natural drying, curing can be accelerated by transmitted light and time can be controlled, resulting in improved mass production and adhesion. This can be said to be a very preferable approach as it allows for stable and uniform products to be obtained. As a light-transmitting mounting member, BK-7 (7,4X 1O-6) and blue plate glass (9,
OX 1O-6), white plate glass (9,3X 10-')
etc. are almost equally preferable, corresponding to the elongation of the ceramic of the solid-state image sensor packaging material.

-20= Further, as a photocurable adhesive, the above-mentioned ultraviolet curing adhesive is preferable because it has a fast curing time and is more resistant to deformation and moisture during curing.
Even for white plate glass, etc., it is 20 to 3, including processing method and material thickness variations.
0% or more, which can be said to be a preferable measure, especially from the standpoint of mass production and cost. In addition, special glass that matches the ultraviolet component light distribution characteristics of the ultraviolet curable adhesive can be selected as the mounting component, making it possible to improve mass production during adhesion, the required adhesion strength, and the stability of adhesion such as curing degree and curing time. By bringing the value closer to the optimum value, it is possible to obtain a value that is more suitable for the device in use.

By the way, as mentioned above, it is difficult to say that a self-liquid type of quick-drying adhesive is a preferable application form because the adhesive shrinks and deforms the adhered object when it dries, but the present invention According to a preferred embodiment of the present invention, it has been found that a quick-drying one-component type adhesive can be effectively used by improving the procedure for attaching objects to be adhered.

That is, when attaching the COD to an optical member (such as a prism) via an attaching member, first, the position of the solid-state image sensor is adjusted relative to the optical member using a positioning method that will be described later.

Next, apply a quick-drying instant adhesive (cyanoacrylate adhesive, one with a primer effect, etc.) to the mounting surface of the mounting member to the light splitting member, and apply Hardlock ESIO (product name), etc. to the joint with the solid-state image sensor. The light splitting member and the solid-state image sensor are bonded and fixed with the mounting member by applying the above-mentioned preferred type of adhesive, such as a two-component type adhesive or a light-curing adhesive such as Threepond TB3062B (trade name). . In this adhesive fixing process, after the light splitting member and the mounting member are fixed with a quick-drying adhesive, fine adjustment of the positioning of the solid-state image sensing device is continued using an adjustment tool to achieve accurate positioning. After the curing of the adhesive that joins the solid-state image sensor and the mounting member is accelerated to some extent (temporary fixing step), the light splitting member and the mounting member are further potted with a suitable adhesive such as the above-mentioned photocuring type. etc. to harden and fix the entire product. (Main fixed adhesion) Since the adjustment is made after positioning the light splitting member and the solid-state image sensor, it is possible to improve the yield by more than 50% compared to the method of gluing and fixing both at the same time. It was recognized that there were significant improvements in terms of performance, cost reduction, etc.

Prism 22 of CCD 25 and CCD 27 according to the invention
For adhesion to, prepare a mounting jig TC in advance.

While gripping the side surfaces of the CCD 25 and CCD 27, the mounting jig holds the optical axes of the spectral A and spectral B as shown in FIG. It is possible to adjust the two directions of V and the rotation direction regarding the X r Y axes, and the mounting jig T
Fine adjustment of C is performed so that there is no pixel shift.

As a mounting jig, for example, the adjustment table can be used in three axial directions (X.

y, z) and also rotatable about the respective axes (e.g. CHUO5EIKIC)
By using a CCD sensor (manufactured by O, Ltd.), it is possible to perform precise positioning between a plurality of CCDs, which is the object of the present invention.

A black and white striped chart image placed at the document position is captured on a CCD 25.
and the images are formed on the CCD 27, and the output signals thereof are recorded on a synchroscope vertically juxtaposed. If the black and white stripe spacing is set based on the designed reduction magnification of the imaging lens and the size of the COD pixel, and a chart is created in which one stripe corresponds to one pixel, the recorded signal superimposed on the synchroscope can be The amount of pixel shift can be easily read. For example, the synchroscope CR7 plane shown in FIG. 7 illustrates a situation where there is a pixel misalignment between the CCD 25 and the CCD 27. Furthermore, by adjusting the mounting jig TC while checking with a synchroscope, the relative position between the CCDs without pixel shift can be determined, and at this position, the CCD 25 and CCD 27 are bonded with adhesive.
are respectively attached to the prism surface of the prism 22 by the mounting member 24 (
26) at the imaging position.

The image reading unit has a plurality of solid-state image sensors fixed to a prism, which is an optical member, using an adhesive corresponding to FIG. 5 via a mounting member made of a ceramic material, and Various comparison tests were conducted on the image reading section that holds the image sensor. The test was carried out by placing the striped chart at the original position and superimposing and comparing the output signals from a plurality of attached solid-state image sensors using a synchroscope, paying particular attention to pixel misalignment.

(1) Vibration resistance test A vibration resistance test was conducted for 30 minutes with the frequency varied, and the pixel misalignment situation before and after was compared. Some of the screws due to mechanical structure had sagging in the threaded parts, and a pixel shift equivalent to about 4 pixels (30 μm) was observed. No pixel shift was observed in the case of this example.

(2) Impact test A 40G drop test was conducted and the pixel misalignment before and after was compared, and pixel misalignment equivalent to about 3 pixels (20 μm) was observed among those due to mechanical structure. No pixel shift was observed in the case of this example.

(3) Temperature test First, the environmental temperature was set to 20°C for 2 hours.
The temperature was raised from °C to 70 °C and the situation of pixel misalignment was compared. In the case of mechanical structure, a pixel shift equivalent to about 4 pixels (30 μm) was observed. The ambient temperature was then restored from 70°C to 20°C over the course of 2 hours. Even in the restored state, it was observed that a pixel shift equivalent to about 2 pixels (15μ+I+) remained due to the mechanical structure. - No pixel shift was observed from beginning to end in the case of the strength wood embodiment.

In the present invention, the COD is fixed to the prism via a mounting member, but the present invention also includes fixing the COD via a separately fixed mounting auxiliary member. FIG. 6 shows an example of this. Since it is not easy to process the irregularities of a prism, a mounting auxiliary member 28 made of a ceramic material with a somewhat complicated shape is prepared and bonded to the prism 22 in advance. By fixing the mounting member 24C (26C) to the auxiliary mounting member 28, the auxiliary member 2
8 and the mounting member 24C (26C) by a sliding guide corresponding to the A direction and a rotational movement in the B direction, it becomes easy to fix the C0D 25 (27) at the adjusted position. FIG. 6(a) shows a front view, and FIG. 6(b) shows a side view.

In the embodiments described above, the light is divided into two colors using the illustrated prism, and a COD is attached to each image formation position, but the present invention is of course not limited to such light dividing means. For example, FIG. 8 shows two right triangular prisms 122a bonded together behind a lens 121 that forms a subject image using a Kester prism type light splitting means.
122b, the slope of the first right triangular prism 122a is set perpendicular to the optical axis, and a surface 123 with dichroic ink characteristics forms a semi-transparent mirror for the light beam incident from this surface.
The image is divided into an R-ah image and a C-ah image, and after being totally reflected on the slopes of the triangular prisms 122a and 122b, they are emitted and sent to the R-ch CCD 1 located nearby.
25 and the C-ah CCD 127, respectively. FIG. 8(a) shows mounting members 1240a and 1240b attached to both sides of the prism.
This is an example in which two CCDs 125 and 127 are adjusted in position and then bonded and fixed using an adhesive so as to satisfy the above-mentioned conditions of equal stress and strain. Mounting members 1260a, 126
At 0b, the ccD125 was adjusted and attached and fixed, and at 1260d, the CCD127 was adjusted and then glued and fixed, and the stress and strain were the same. It is designed to satisfy the following conditions.

Furthermore, FIG. 9 shows a side view of a reading device using the light splitting means described in Japanese Patent Application No. 157005/1988 filed by the present applicant. The above-mentioned prism 22 is bonded to the rear of the lens 221 that forms a subject image.
The prism 222 is divided into three colors of blue, green, and red using the prism 222.
ccD225B was located in close proximity to .

The images are formed on the light receiving surfaces of 225G and 225R, respectively.

Figure 9(a) shows the mounting members 2 glued to both sides of the prism.
CCD 225B is adhesively fixed to 240Ba and 2240Bb using position adjustment adhesive, and mounting members 2240Ga and 22 are also adhered to both sides of the prism.
For 40Gb, use CCD225G and mounting member 2240Ra.
, 2240Rb, the CCD 225R was adjusted in position and then glued and fixed to satisfy the above-mentioned conditions. In addition, Fig. 9(b) shows that the solid-state image sensor is divided into 1 and 2 parts, CCD225G and C0D225.
Mounting members 224 glued to both sides of the prism for R
After adjusting the position of 0GRa and 2240GRh, glue and solidify 225B, 225G, 225R.
After adjusting their positions, they are glued and fixed to satisfy the above conditions.

8 and 9 each show an example of a COD fixing method when using different light splitting members, and in both cases the mounting member is bonded to the side surface of the prism. It is not limited to.

〔Effect of the invention〕

Using a method of fixing each solid-state image sensor using a pair of mounting members that can evenly propagate heat to both sides of the light splitting member of the reading unit, as in the present invention, eliminates many factors that cause pixel misalignment. As a result, a clear and excellent color image can be reproduced and obtained by the color image reading device of the present invention, and the image quality will not deteriorate due to the pixel misalignment due to changes in the environment or the passage of time. This eliminates the need for complex electrical correction circuits for the pixel misalignment and color ghost correction, and provides 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. By making the lens barrel and prism integral in advance, it is possible to achieve highly accurate and stable image reading without the occurrence of problems such as the following:
It is possible to obtain a device that is also effective in preventing pixel shift after fixing the OD.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a color image forming apparatus equipped with a color image reading device of the present invention. FIG. 2(a), FIG. 2(C), FIG. 3, FIG. 4, FIG. 5, and FIG. 6 are explanatory views showing examples of mounting the solid-state image sensor according to the present invention. FIG. 2(b) is a perspective view showing a combination of a lens barrel and a prism. FIG. 7 is an explanatory diagram of a method for adjusting the position of a solid-state image sensor. 8 and 9 are detailed explanatory views of the present invention for other types of light splitting members. FIG. 10 is a perspective view showing the adjustment direction of the solid-state image sensor. FIG. 11 is a sectional view of a conventional reading unit. 20--One reading unit

Claims (7)

[Claims] (1) In a reading device in which a solid-state image sensor is provided at an image-forming position of an optical system including an imaging lens and a light splitting member and is fixed to the light splitting member with an adhesive via a mounting member, the solid-state image sensor A reading device comprising a mounting member that equalizes heat propagation from both sides to the light splitting member. (2) The reading device according to claim 1, wherein the adhesive is a two-component type adhesive. (3) The reading device according to claim 1, wherein the adhesive is a photocurable adhesive. (4) The reading device according to claim 3, wherein the photocurable adhesive is an ultraviolet curable adhesive. (5) The reading device according to any one of claims 1 to 4, wherein the mounting member is made of a ceramic material. (6) The reading device according to any one of claims 1 to 4, wherein the mounting member is made of an invar alloy. (7) The reading device according to any one of claims 1 to 4, wherein the mounting member is an iron member.