JPS6328166A - Reader - Google Patents

Abstract

PURPOSE:To prevent aberration among solid-state image pickup elements to each other from occurring, and to attain image reading most stable for all of the conditions such as the fluctuation of a temperature, change with the of time lapse vibration, and shock, etc., by mounting a mounting member which mounts the solid-state image pickup element, and a holding member which holds an image forming lens, through an adjusting mechanism. CONSTITUTION:A red channel CCD25, and a cyan channel CCD27 which are the line image sensors of the soild-state image pickup elements, on the right and left end of which the mounting member 25a, or 27a is stuck and fixed in advance, are mounted on a supporting part 21d through the mounting members 25a, and 27a. As the order of mounting, the members are set at tentative mounting states by a screw member S which engages with the supporting part 21d first, through respective lengthy hole T. Afterwards, the position adjustments of the mounting members 25a and 27a are performed by moving in the vertical direction of a light receiving plane, and they are set at respective light receiving plane of a prism 22 correctly, and after that, the screw member S is screwed tightly, and furthermore, bonding is performed, then they are fixed on the holding member 21a.

Description

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

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. C.C.
The present invention relates to a reading device provided with an image reading section that reads an optical image using a solid-state image sensor as described in I);

[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. For example, the solid-state image sensor is 1 line image sensor Toshiba 11jTcD 106C.
It is composed of an array of pixels of about 7μl, so
In the embodiment shown in FIG. 1, which will be described later, if the correspondence of the light image incident on the image sensor exceeds approximately 1 pixel (approximately 2 μl), other colors such as black characters, for example, are displayed as 7 lines at the periphery of the reproduced image.
Color ghosts of red, blue, etc. appear around the edges of shapes. This effect becomes particularly noticeable when a deviation of one pixel (approximately 7 μl) or more occurs in the above-mentioned correspondence. To prevent this color ghost, electrical correction is generally performed. However, if most of the color ghosts are removed by electrical processing, the memory capacity required would be extremely large, and problems such as variations in line thickness would occur in the image, 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.
2b to form a unit, and as shown in FIG. 7, the unit can be adjusted in two spatially orthogonal axes, including the optical axis direction, X + Y, and in the rotation direction about the x and y axes, The above proposal allows fine adjustment of the installation of each solid-state image sensor, and immediately after adjustment, there is almost no correspondence between each element. It was meant to match. However, as shown in FIG. 8, the light splitting prism 54, which is an optical member provided behind the condensing lens 53, and the solid-state image sensors 51a and 51b are each attached to a frame, and there are many holding members, e.g. Adjust the part with the adjustment screw 5! ! These parts are installed in an orderly manner, and these parts are subject to thermal expansion and contraction due to temperature changes, and screw li! Misalignment is likely to occur due to misalignment, errors, etc., and it has not been easy to eliminate pixel misalignment, including in terms of restorability. 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. . Also, even if the solid-state image sensor is set up in a jig quite firmly, the final tightening of screws, etc. will be done with torque and when removed from the jig, the distortion will return by a few microns.
For example, even if the parts are set accurately within 181 degrees, due to the stress strain inside the parts, it has been observed that a shift of several microns or more may occur during impact tests, etc. Furthermore, there is a drawback that the temperature test results may have installation errors due to the thermal expansion coefficient of the support member. In addition, in order to fix the solid-state image sensor,
There is also a proposal for fixing using adhesive according to No. 70, but this proposal is related to fixing a single solid-state image sensor.
Moreover, it is not a device that fixes to an optical member, but a device that attempts to adjust and fix the solid-state image sensor for 7 frames. This method has not been applied to image reading using an image sensor that requires high-precision maintenance without positional deviation.

[Problem that the invention seeks to solve]

The object of the present invention is 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 image sensors are arranged and the image formed by each solid-state image sensor is read and signal processing is performed. Furthermore, it is required that the images formed by the solid-state imaging devices correspond to each other accurately. 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.

[Structure of the invention]

The above object is a reading device that reads an optical image by a solid-state image sensor provided at an image-forming position of an optical system consisting of an imaging lens and a light splitting member, a member for attaching the solid-state image sensor and a holding member for holding the imaging lens. This is achieved by a reading device characterized in that it is attached via an adjustment mechanism.

【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 image reading device A, 1 is a platen glass;
ii2 is placed on this platen glass 1. The original 8% 2 is illuminated by fluorescent lamps 5 and 6 mounted on a carriage 4 moving on a slide rail 3. The movable mirror unit 8 is provided with mirrors 2-9 and 9', which move on the slide rail 3, and which combination of the first mirror 7 provided on the carrier 4 is used to transfer the optical image of the original v42 on the platen plus 1 to the lens reading unit. ,, )20. The carriage 4 and the movable mirror unit 8 are driven by a stepping motor 10 via a wire 15.
711, 12, 13, 141:! '), 1tfNV and [/' are driven in the same direction at a speed of 1/2V. Standard white plates 16 and 17 are provided on the back side of both ends of the platen plus 1, and are configured so that a standard white signal can be obtained before the start of original reading scanning and after the end of scanning. The lens reading unit 20 includes an imaging lens 21 as a reading lens system, a prism 22 as a light decomposition means,
It is composed of a red channel (hereinafter referred to as R-ch) CCD 25 and a cyan channel (hereinafter referred to as C-ch) CCD 27, which are line image sensors of the solid-state image sensor. The original optical image transmitted by the first mirror 7, mirror 9, and mirror 9' is focused by the lens 21, and the prism 22
The light image is separated into a R-ah image and a C-ah image by a guichroic mirror provided inside, and each light image is adjusted to the prism 22, which is an optical member, and to the holding member that holds the lens 21 in the background. ? R fixed via 3'll
-chccD25 and C-ah are respectively imaged on the light receiving surfaces of CCD27. The fluorescent lamps 5 and 6 are commercially available warm white fluorescent lamps to prevent emphasis or attenuation of specific colors based on the light source when cutting color originals, 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 R-ah CCD25 and C-cl+ CCD27
The image signal output from the is processed through a signal processing unit (not shown), and a color signal separated according to the color of the toner is output and input to the honor unit (B), where it is generated by a semiconductor laser. The images produced by each of the laser beams are sequentially projected onto the circumferential surface of the photosensitive drum 31, and after each projection, the images are developed by developing rollers I, n, and IIl to form a color image using three-color toners. 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 polarization pole 32, and then the recording paper is separated and discharged to the outside of the apparatus via a fixing device 33. Then, the color image reproduction is finished. The configuration of the lens reading unit 20 in the reading device, that is, the lens barrel 21, the prism 22, and the attachment of the R-ch CCD 25 and the C-ch CCD 27;
The holding is carried out as shown in FIGS. 2 and 3. That is, FIGS. 2 and 3 show the first and second embodiments of the reading device of the present invention, in which the lens barrel 211 and the prism 22 are mounted and supported by the following common means. It is being done. The lens mirror 11M21 is attached to the holding member 2 as shown in the figure.
The V-shaped receiver 1a, which opens at right angles upward, is housed in a section, fixed by a fastener 21c, and then attached to a predetermined position on the device board 40. Further, in this embodiment, as shown in FIG.
The prism 22 is fixed to the prism 1b by adhesive. Since the mounting surface 21b is formed by a simple turning process, the distance from the imaging lens accommodated in the lens l[21 and the perpendicularity to the optical axis thereof are extremely accurate, and the prism 2Z mounted thereon has extremely high precision. R mentioned above through
A predetermined light image can be correctly formed on the light receiving surfaces of the -ch CCD 25 and the C-ch CCD 27. In other words, as shown in FIG.
The way to determine the amount of slant of SRL' is that the amount of slant is 3 in 10 minutes in terms of the normal value of 30% or more, which is determined from the signal output of the white line part and the black line part against the white background shown in the fjS5 figure.
'i! The decrease was around i11 (9%), and the angle was further reduced by 30
The lens mirror W421 and the prism 22 should be fixed together in advance to maintain the surface accuracy during this period, as this will cause a decrease of more than 50% (15%), which will hinder the extraction of black and white discrimination signals. By doing so, it is possible to prevent a decrease in the defective rate in the post-production process, which not only provides cost benefits, but also reduces the influence of the material of the holding member 21a, the mounting member 24, etc. on pixel misalignment after the CCD is attached, and is even more effective. Demonstrate. As for the fixing method, in addition to the above-mentioned adhesive method, mechanical gt#! Effective methods include integrating the lens barrel 21 and the prism 22 into the holding member 21a, and setting the lens barrel 21 and the prism 22 on the holding member 21a and holding them together (see FIG. 4(b)). For adhesion of the prism 22 to the lens barrel 21, an adhesive that has adhesive strength and can withstand various environmental tests is selected and used. The same adhesive is used for adhesion of the CCD 25. The installation of 27 and 27 will be comprehensively explained in the section explaining the fixing. Next, I will explain about the installation and fixing of CCD25.27.
In the first embodiment, as shown in FIG. 2, a portion of the holding member 21a extends to the side surfaces of the prism 22, so that the holding member 21a can hold the left and right side surfaces of the prism 22 without contacting it. A support portion 21d having a laterally symmetrical shape is formed. On the other hand, the CCD 25 and CCD 27 have mounting members 25a or 27a adhesively fixed to their left and right ends, respectively, so that they can be attached to the support portion 21d via the mounting members 25a and 27a. but,
The mounting order is as follows: First, the screw member S screwed into the support part 21cl is put into a similar state through each elongated hole T, and then the mounting member 25a is attached along the elongated hole T.
and 27a in a direction perpendicular to the light-receiving surface to adjust their positions and set them correctly on the respective light-receiving surfaces of the prisms 22, and then tighten the screw members S and further bond them to fix them to the holding member 21a. It is supposed to be done. Furthermore, in the second embodiment, as shown in FIG. 3, the holding member 21'a that holds the lens barrel 21 is cut off at a portion corresponding to the rear end surface of the lens barrel 21; A mounting member 21'd having protrusions 25'a and 27'a extending close to each light-receiving surface of the prism 22 on the surface thereof is formed so that it can be screwed and further bonded. It should be noted that the mounting members 21'a are symmetrical and can be integrally mounted. In the case of this embodiment, as in the first embodiment described above, the CC
D25 and 27 are first adhesively fixed to the protrusions 25'a and 27'a of the mounting member 21'd, respectively, and then attached to the holding member 21'a. The order of mounting is that first, the CCD 25 is temporarily fixed through the two elongated holes T' with the screw member S' screwed into the mounting surface, and then the CCD 25 is attached along the elongated holes T'.
and 27 are moved in a direction perpendicular to the light-receiving surface to adjust their positions and set correctly on each light-receiving surface of the prism 22, and then the screw member S' is tightened to further bond the holding member 21'a. It is now fixed to . Further, the mounting members 25a, 27a or 21'd may be partially modified in shape, for example, as shown in FIG.
It is also possible to support the solid-state image sensor on only one side as shown in a), and as shown in Figure 6(b), multiple poles) B and N are attached and tightened to press the mounting members to each other. It is also possible to sandwich and support the solid-state image sensing device by arranging it so that it can be supported. In addition, as a mounting member having the above adjustment mechanism, Fig. 2.3.6
In this example, a single part is used as an example, but it goes without saying that it can be made up of a plurality of parts. The mounting member is preferably made of a material with a small coefficient of linear expansion, in order to prevent pixel misalignment due to temperature fluctuations. Pixel misalignment due to temperature fluctuations can be reduced by making the fixing conditions of each CCD with the mounting member exactly the same. The linear expansion coefficient of a normal prism is 7.4 x 10-' (Optical Plus BK-7 ), glass or ceramic materials (7.0~8.4X 10-') are used as the mounting material.
and low thermal expansion alloys (e.g. Invar alloy (1~3X 10
-'), Nirenos) cast iron (4 to IOX 10-')), etc., and aluminum material (25X 10-') is not so suitable. The present inventors conducted tests using various materials as mounting members, but no image shift due to thermal expansion was detected when using a plastic material, a ceramic material for the collar, and a low thermal expansion alloy. In the above embodiment, the holding member of the lens barrel and the mounting member, and the mounting member and the CCD were fixed in place before adhesion, and when the relative positions of each CCD were adjusted for the divided optical images, Fig. 2 And in FIG. 3, the structure is tightly fixed with adhesive. In particular, in Fig. 2, even if iron with a large linear expansion coefficient (12X to -') is used as the mounting member, the lengthwise dimension is short in practical terms, so the elongation due to heat is not affected much, and the depth direction is line-wise. This is the direction in which the sensors are arranged, and since the prism material and the line sensor baccane material are ceramic materials, their coefficients of linear expansion are approximately the same, and no pixel misalignment occurred in 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 photocurable adhesives, ultraviolet curable adhesives are most preferable as adhesives to be used in the present invention. Adhesives include epoxy, acrylic, etc., and are further divided into 1-part type and 2-part type.
Liquid-based types usually contain a GLL stand-by curing agent, and when used, they gradually harden, dry, and solidify when exposed to air, etc., so they take a long time to harden, and the degree of hardening and time of hardening vary. Due to irregular shrinkage, 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. Second point: Two-component and instant-acting products are cured in a few minutes at most by kneading the curing agent and the main ingredient during adhesion, shortening the curing time and stabilizing the degree of curing. , which is effectively suited for this purpose. In addition, it is a one-component type with immediate effect, cyano 7 crery) i? Although there is an S-type adhesive, it is not necessarily a preferred form of application because it causes adhesion during impact and deformation of the adhered object 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 the environmental tests described later. . At the time of bonding, an attempt was made to shorten the bonding time by carefully changing the temperature conditions, 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 ThreeBond TB30 as a photocurable adhesive.
60B (product name), electrification 1045K (product name), Norland 65 (product name)'! ? When bonding was carried out in a short time by irradiating ultraviolet light with a high-pressure mercury lamp, good results were obtained in the environmental tests described later. 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 against moisture 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. In addition, if the device is to properly arrange the positional accuracy of adhesive members, it is possible to apply adhesive in advance to the adhesive surface of each adhesive member in spots or areas.
The bonding surface of the bonding member may be immediately pressed and bonded. Prism 22 of CCD 25 and CCD 27 according to the invention
4 to! Prepare the mounting jig TC in advance. While gripping the side surfaces of the CCD 25 and CCD 27, the mounting jig is used for each optical axis of the spectral beam and the spectral beam B as shown in the fjfJS diagram. It allows adjustment in the two directions of y and the rotation direction regarding the x and y axes, and the mounting jig TC
Adjust so that there is no pixel shift by fine adjustment. A black and white striped chart image placed at the document position is captured on a CCD 25.
and an image is formed on the CCD 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 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. 5 has a CCD2
This is an example of a situation where there is a pixel misalignment between CCD 27 and 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 first CCI) 25 and CCI) 27 are performed using adhesive. In the case of the example, each holding member 21
It is fixed to the support portion 21cl of a at an image forming position via a mounting member 25a (27a). The solid-state image sensor is held in place by the image reading section, which is fixedly mounted via a mounting member made of ceramic material in the format shown in FIGS. 2 and 3, and the mechanical structure shown in FIG. Various comparison tests were conducted on the image reading section. 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 F A vibration resistance test with a variable frequency was conducted for 30 minutes, and the pixel deviation situation before and after was compared. A pixel shift equivalent to 30 μl) was observed. No pixel shift was observed in the case of this example. (2) Impact test) Perform a 40G drop test,
Comparing the pixel deviation before and after, it was found that there was a pixel deviation equivalent to about 3 pixels (20 μl) in the case of machine ↑ purchase. 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.
Comparing the situation of pixel misalignment after raising the temperature from ℃ to 70℃
In the case of mechanical structure, a pixel shift equivalent to about 41ii elements (30 μm) was observed. Then 70° between 21 and 7
The environmental temperature was restored from 20°C to 20°C. Even in the restored state, it was observed that a pixel shift equivalent to about 2 pixels (15 μl) remained due to the mechanical structure. - From beginning to end, everything is based on the power wood example! No deviation was observed.

【Effect of the invention】

When the holding member of the imaging lens and the solid-state image sensor are fixed at the imaging position M using a simple mounting member as in the present invention, many factors that cause pixel misalignment are removed. Thus, a clear and excellent color image can be reproduced and obtained by the color image reading device of the present invention, and there will be no deterioration in image quality due to the pixel shift due to 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 the present invention has excellent effects such as durability.Also, as explained in the embodiments, the present invention uses filling adhesive. However, since it uses a method similar to close-contact adhesive, there is no shrinkage when the adhesive hardens compared to the commonly used filling adhesive, and stable image reading with high accuracy is possible. At the same time, by integrating the lens fi body and prism in advance, the device is cheaper, has better stability, and is also effective in preventing pixel misalignment after the CCD is fixed. can be obtained.

[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, FIG. 3, and FIG. 6 are explanatory diagrams showing the fixed state of the solid-state image sensor of the present invention. FIG. 4 is a schematic diagram showing a combination of a lens barrel and a prism. FIG. 5 is an explanatory diagram of a method for adjusting the position of a solid-state image sensor according to the present invention. FIG. 7 is a perspective view showing the g-alignment direction of the solid-state image sensor. FIG. 8 is a schematic diagram showing the mounting structure of a conventional solid-state image sensor. 21-...Lens @ ff4 21a, 21'a-
Holding member 21d...Support part 22...Prism 25.27-CCD 21'd, Z5a
, 27a-attachment member 25'a, 27'a... protrusion
s, s'...Screw members T, T'...Elongated hole Applicant Konishiroku Photo Industry Co., Ltd. α1 Group Cd Ward! Tesho! ? Figure 5 Figure 6 (a) Figure 6 (o) 25'a (27'a) (,

Claims (5)

[Claims] (1) In a reading device that reads an optical image using a solid-state image sensor provided at an image-forming position of an optical system consisting of an image-forming lens and a light splitting member, a mounting member for attaching the solid-state image sensor and a holder for holding the image-forming lens A reading device characterized in that the member is attached via an adjustment mechanism. (2) The reading device according to claim 1, wherein the adjustment mechanism is fixed with an adhesive after adjustment. (3) The reading device according to claim 1 or 2, wherein the solid-state image sensor is attached to the attachment member using an adhesive. (4) Any one of claims 1 to 3, wherein the material of the holding member is a ceramic material.
The reading device described in Section 1. (5) Any one of claims 1 to 4, wherein the material of the mounting member is a ceramic material.
The reading device described in Section 1.