JP2008160195A - Image reading device, image forming apparatus, and method for adjusting image reading device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily focus illumination rays of light on reading focal points in an image reading device. <P>SOLUTION: This image reading device 300 is provided with an illuminating device equipped with a light source and a plurality of illumination lenses for dividing a light flux to be emitted from the light source into a plurality of light fluxes by the illumination lenses, and for emitting the plurality of divided light fluxes on an original face 31, and configured to control image pickup elements to form the image of reflected rays of light from an original illuminated by the illumination device with image forming lenses, and to linearly read an original 30 in a main scanning direction, and to read the original in a sub-scanning direction orthogonal to the main scanning direction for reading a plane image, wherein the focal position of the illumination device 10 is made adjustable. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a reduction optical system image reading device equipped with a solid-state imaging device, an imaging lens, and an illumination device, an image forming apparatus including the image reading device, and an adjustment method for the image reading device. About.

Patent Document 1 describes the following as an illumination device used in the above-described image reading apparatus. This is an illumination that can be easily adjusted with high flexibility in light quantity, light quantity distribution, and color in an illumination apparatus used for an image reading apparatus, a photosensitive material exposure apparatus, and an exposed photosensitive material fixing apparatus. In order to provide a device, a cylindrical main body whose inner surface is a reflection surface or a diffuse reflection surface, a light source for entering light into the main body, and a slit shape provided on the side wall of the main body and extending in the longitudinal direction of the main body The light exit port, one or more slit-shaped control plate insertion ports provided on the side wall of the main body, and a control having optical characteristics different from the inner surface of the main body inserted along the inner surface of the main body from the control plate insertion port And a board.
JP 2004-297206 A

  However, when the illumination device described in the patent related to the present invention is used, the illumination focus is limited to a certain range in order to increase illumination efficiency as a feature of the illumination device. A good image may not be read unless the focal points are matched with a certain degree of accuracy.

  SUMMARY An advantage of some aspects of the invention is that it provides an image reading apparatus, an image forming apparatus, and an image reading apparatus adjustment method capable of easily matching the focus of illumination light and the reading focus.

  The invention of claim 1 includes a light source and a plurality of illumination lenses. The illumination lens divides a light beam emitted from the light source into a plurality of light beams, and irradiates the divided light beams by superimposing them on the document surface. An illuminating device is provided, and reflected light from the original illuminated by the illuminating device is imaged on an image sensor by an imaging lens, and the original is linearly read in the main scanning direction, while being sub-scanned perpendicular to the main scanning direction. In the image reading apparatus which reads in a direction and reads a planar image, the focus position of the illumination device can be adjusted.

  According to a second aspect of the present invention, in the image reading apparatus according to the first aspect, the arrangement position of the illuminating device is made variable, and the position of the illuminating device is adjusted so that the illuminating focal position matches the reading focal position. With features.

  According to a third aspect of the present invention, in the image reading apparatus according to the first aspect, a reflection mirror having a function of focusing illumination light is provided, and the reflection mirror can be adjusted.

  According to a fourth aspect of the present invention, in the image reading apparatus according to the first aspect, an illumination light reflecting mirror is provided, and the reflecting mirror is adjustable.

  According to a fifth aspect of the present invention, in the image reading apparatus according to the third or fourth aspect, the reflecting mirror has an angle adjusting mechanism for adjusting a mounting angle of the reflecting mirror.

  According to a sixth aspect of the present invention, in the image reading apparatus according to any one of the third to fifth aspects, the reflecting mirror has a position adjusting mechanism for adjusting a mounting position of the reflecting mirror.

  A seventh aspect of the present invention is an image forming apparatus comprising the image reading apparatus according to any one of the first to sixth aspects.

  The invention of claim 8 includes a light source and a plurality of illumination lenses. The illumination lens divides a light beam emitted from the light source into a plurality of light beams, and irradiates the divided light beams by superimposing them on the document surface. An illuminating device is provided, and reflected light from the original illuminated by the illuminating device is imaged on an image sensor by an imaging lens, and the original is linearly read in the main scanning direction, while being sub-scanned perpendicular to the main scanning direction. An adjustment method for an image reading apparatus, wherein the focal position of the illumination device is adjusted in an adjustment method for an image reading apparatus that reads in a direction and reads a planar image.

  According to a ninth aspect of the present invention, in the image reading apparatus according to the eighth aspect of the present invention, when the focus position of the illuminating device is adjusted, an illuminometer is used to determine whether the adjustment value is correct or not.

  According to a tenth aspect of the present invention, there is provided an image reading apparatus adjusting method, wherein after adjusting the illumination focal position according to the ninth aspect, the reading characteristic is adjusted using the illumination light.

  According to an eleventh aspect of the present invention, in the adjustment method for the image reading apparatus according to the eighth aspect, when the focal position of the illuminating device is adjusted, an image sensor is used to determine whether the adjustment value is correct or not.

  According to a twelfth aspect of the present invention, there is provided an adjustment method for an image reading apparatus, wherein after adjusting the reading characteristic value by the adjustment method according to the eleventh aspect, the illumination focal position is adjusted.

  According to the thirteenth aspect of the present invention, after the predetermined characteristic of the reading characteristic is adjusted by the adjustment method according to the eleventh aspect of the invention, the illumination focal point position is adjusted, and the reading characteristic is readjusted by the illumination light that has been adjusted for the illumination focal point. This is a characteristic adjustment method for an image reading apparatus.

  According to the present invention, it is possible to easily match the focus of the illumination light with the reading focus and to perform good image reading.

  Embodiments as the best mode for carrying out the present invention will be described below with reference to the drawings.

  An image reading apparatus according to an embodiment of the present invention will be described below. FIG. 1 is a sectional view conceptually showing an image forming apparatus such as an electrophotographic copying machine or printer according to the present invention. The main configuration of the image forming apparatus of this embodiment is 111 as a reading unit that is an image reading apparatus that reads a document, and is sent from an image forming unit 112 that forms an image, an automatic document feeder (ADF) 113, and an ADF 113. A document discharge tray 114 for stacking originals to be stacked, a paper feed unit 119 including paper feed cassettes 115 to 118, and a paper discharge unit (discharge tray 120) for stacking recording sheets.

Then, when the document D is set on the document table 121 of the ADF 113 and an operation unit (not shown), for example, a print key is pressed, the uppermost document D is sent out in the direction of the arrow B 1 by the rotation of the pickup roller 122. Then, by the rotation of the document conveying belt 123, the paper is fed onto the contact glass 124 fixed to the image reading unit 111 and stops there. The image of the document D placed on the contact glass 124 is read by the reading device 125 positioned between the image forming unit 112 and the contact glass 124. The reading device 125 includes a light source 126 that illuminates the document D on the contact glass 124, an optical system 127 that forms an image of the document, a photoelectric conversion element 128 that includes a CCD that forms an image of the document, and the like. After the image reading is completed, the document D is transported in the direction of the arrow B2 by the rotation of the transport belt 123 and discharged onto the document discharge tray 114. In this way, the document D is fed one by one onto the contact glass 124 and the document image is read by the image reading unit 111.

On the other hand, inside the image forming unit 112, a photoreceptor 130 as an image carrier is disposed. The photoconductor 130 is driven to rotate clockwise in the drawing, and the charging device 131 charges the surface to a predetermined potential. Further, the writing unit 132 emits laser light L that is light-modulated in accordance with image information read by the reading device 125, and the surface of the charged photosensitive member 130 is exposed with the laser light L, whereby the photosensitive member is exposed. An electrostatic latent image is formed on the surface 130. When the electrostatic latent image passes through the developing device 133, the electrostatic latent image is transferred to the recording medium P fed between the photosensitive member 130 and the transfer device 134 by the opposing transfer device 134. The surface of the photoreceptor 130 after the toner image transfer is cleaned by a cleaning device 135.

A plurality of paper feed cassettes 115 to 118 arranged at the lower part of the image forming unit 12 contain recording media P such as paper, and the recording media P is fed from any of the paper feed cassettes 115 to 118 in the direction of arrow B3. The toner image formed on the surface of the photoreceptor 130 as described above is transferred onto the surface of the recording medium P. Next, the recording medium P is passed through the fixing device 140 in the image forming unit 112 as indicated by an arrow B4, and the toner image transferred to the surface of the recording medium P by the action of heat and pressure is fixed. The recording medium P that has passed through 136 is conveyed by the discharge roller pair 137, discharged to the discharge tray 120 as shown by an arrow B5, and stacked.

  Next, an image reading apparatus to which the present invention is applied will be described. As the image reading apparatus, those according to the first and second examples described below can be used. First, the overall structure of the image forming apparatus according to the first example will be described. FIG. 2 is a perspective view showing the overall configuration of the image reading apparatus according to the first example, and FIG. 3 is an enlarged front view showing a main part of the image reading apparatus shown in FIG.

  An image reading apparatus that is an image reading unit 111 includes an illumination device 10 including a light source, an imaging lens, and the like, a line sensor imaging device 20, a plurality of turning mirrors 211, 221, 222, and a focusing mirror 212. The image of the original 30 illuminated in step (2) is read linearly (two-dimensionally) in the main scanning direction, and scanned in the sub-scanning direction to read a planar (two-dimensional) image.

  For this reason, the image reading apparatus 200 according to this example includes a first traveling body 210 on which the turning mirror 211 and the focusing mirror 212 are mounted, and a second traveling body 220 on which the turning mirrors 221 and 222 are mounted. The first traveling body 210 and the second traveling body 220 are moved at different speeds.

  The document 30 is placed on a contact glass 124 to which the document surface 31 is in close contact, and light from the illumination device 10 is reflected by the turning mirror 211 and the turning mirrors 221 and 222 to enter the imaging region 23 of the document 30. Irradiated. The focusing mirror 212 disposed on the first traveling body 210 has a curved surface for efficiently irradiating the original 30 with light from the illumination device 10. The reflected light from the document 30 is imaged on the line sensor image sensor 20 by the imaging lens 21 through the deflecting mirror 211 and the deflecting mirrors 221 and 222, and the line sensor image sensor 20 converts the image in the imaging area 23 to 1. Acquire in a dimension.

  In this example, the first traveling body 210 and the second traveling body 220 are driven by the motor 24 and the transmission means 25, and the first traveling body 210 is caused to travel at twice the speed of the second traveling body 220. As a result, the line-shaped imaging region 23 on the surface of the contact glass 124 travels while maintaining the state of being imaged on the reading surface of the line sensor imaging element 20 by the imaging lens 21. Then, the image of the document surface 31 of the document 30 on the contact glass 124 is sequentially read out by the line sensor imaging device 20 and acquired two-dimensionally. The moving direction of the first traveling body 210 is referred to as a sub-scanning direction, and the direction read by the line sensor image sensor 20 is referred to as a main scanning direction.

  Usually, a one-dimensional CCD is used as the line sensor imaging device 20, and the imaging lens 21 forms an image on the line sensor imaging device 20 as a reduced image of the original image on the contact glass 124. In addition, since the traveling speed ratio between the first traveling body 210 and the second traveling body 220 is set to 2: 1, the moving distance of the second traveling body 220 is half of the moving distance of the first traveling body 210, The distance from the imaging region 23 to the imaging lens 21 and the line sensor imaging device 20 is constant regardless of the positions of the first traveling body 210 and the second traveling body 220.

  Next, the overall structure of the image forming apparatus according to the second example will be described. FIG. 4 is a perspective view showing the overall configuration of the image reading apparatus according to the second example, and FIG. 5 is an enlarged front view showing a main part of the image reading apparatus shown in FIG.

  In the image reading apparatus 300, the illumination device 10 and the line sensor imaging device 20 are mounted on one traveling body 310, and the traveling body 310 moves to read a two-dimensional document image. In the traveling body 310, the illumination device 10 and the line sensor imaging device 20 are arranged in parallel in the main scanning direction. The traveling body 310 includes the imaging lens 21, a focusing mirror 312 including a plane mirror unit 316, a turning direction. A mirror 313 and a turning mirror 314 are disposed. In the image reading apparatus 300, the light from the illumination device 10 is irradiated to the imaging region 23 via the turning mirror 314, the turning mirror 313, and the focusing mirror 312, and the reflected light from the document 30 is reflected to the focusing mirror 312, the plane mirror. An image is formed on the imaging surface of the line sensor imaging element 20 from the deflecting mirror 314, the correction lens 315, and the imaging lens 21 via 316. In this example, the image of the imaging region 23 is formed on the imaging surface of the line sensor imaging element 20 regardless of the position of the traveling body 310.

  Hereinafter, an illumination device used in the above-described image reading apparatus will be described. As the lighting device, ones having configurations according to first to fifth examples described below can be used.

  6A and 6B are views showing first to third examples of the illumination device, wherein FIG. 6A is a plan view common to the first to third examples, FIG. 6B is an enlarged front view of the first example, and FIG. Is an enlarged front view of the second example, and (d) is an enlarged front view of the third example.

  First, the first example will be described. As shown in FIG. 6A, the illumination device 400 includes an LED array 410, a rotating parabolic mirror array 420 (PR) disposed behind the LED array 410, and a main array disposed in front of the LED array 410. A condenser lens 430 (CA1), a main illumination lens 440 (CA2) disposed in front of the main condenser lens 430, and a main integrated lens 450 (L) disposed in front of the main illumination lens 440 are provided.

  The LED array 410 is configured by arranging a plurality of light emitting diodes 411 in one row. In order to obtain white light, a light emitting diode 411 having three colors of R (red), G (green), and B (blue) is used. In FIG. 6A, only four are shown, but a total of three at least one for each color is sufficient, and even an integer multiple of the light emitting diodes 411 with a small amount of emitted light considering the color balance. May be increased.

  The rotating parabolic mirror array 420 is configured by arranging a plurality of rotating parabolic mirrors 421 in one line. Each rotary paraboloid mirror 421 places a light emitting diode 411 at the focal position, and reflects the light beam emitted from the light emitting diode 411 into parallel light. Since the light emitting surface of the LED has a certain area rather than a point, the luminous flux emitted from other than the focal position diverges from the parallel light and diverges and deviates from the parallel light as the focal point deviates. A representative example of the light distribution characteristic is shown in FIG.

  The main illumination lens 440 is a cylinder lens array that illuminates the irradiation target surface (reading region) by expanding the light beam that has become parallel light in the rotary paraboloid mirror array 420. The configuration is such that cylinders (lenses) are arranged as shown in FIG. The focal length is preferably f2 = 1 / ((1 / a) + (1 / c)) (see FIG. 6C).

  The main condensing lens 430 efficiently enters parallel light including divergent light into the main illumination lens 440, and includes a cylinder lens array. The configuration is the same as that of the main illumination lens 440, and the focal length is preferably f1 = c. However, even if f2 is the same as that of the main illumination lens 440, the efficiency is hardly lowered. If the main condensing lens 430 and the main illumination lens 440 have the same configuration, the management burden during manufacturing, sales, and service is reduced.

  The main integration lens 450 is a convex lens, and aligns the secondary optical axis of the light beam divided by the main condenser lens 430 and the main illumination lens 440 with the center of the illumination target surface, and the light beam illuminated by each cylinder of the main illumination lens 440. Superimpose on the surface to be illuminated. The focal length is F = a (see FIG. 6B). The main integration lens 450 has a shape obtained by cutting an unnecessary portion in the sub-scanning direction in a general circular convex lens.

  With such a configuration of the illumination device, all the luminous fluxes passing through the width m of the cylinder (lens), which is each element of the main condenser lens 430 and the main illumination lens 440, which are the cylinder lens array, are read areas on the illumination target surface. Irradiation is performed within a width M of 460 (see FIG. 6B).

  In this case, the effect of the profile formed by the light emitting diodes 411 and the rotating paraboloid mirror array 420 is not caused by matching the number of light emitting diodes 411 with the number of cylinders in the main condenser lens 430 and the main illumination lens 440 in the cylinder array. The surface to be illuminated can be made uniform. However, when the number of cylinders exceeds twice the number of light emitting diodes 411, it may be an integer multiple.

  Next, the illumination state in the sub-scanning direction in the first example will be described with reference to FIG. The process until the light beam from the light emitting diode 411 is emitted from the rotating parabolic mirror array 420 is the same as that in FIG. Here, the main condensing lens 430 and the main illumination lens 440 have no optical power when viewed from the illustrated direction, and behave in the same manner as a parallel plate. Therefore, the light emitted from the paraboloid mirror array 420 is parallel light. Pass through. The parallel light flux is focused by the main integrated lens 450 and focused on the reading area 460 on the illumination target surface.

  In this case, the divergent light beam deviates from the focal position and illuminates the illumination target surface. The illuminance distribution reflects the light distribution shown in FIG. Considering the half value width of the light distribution, for example, a width such as M ′ may be irradiated (see FIG. 6B).

  In this example, the size of the light emitting surface of the light emitting diode 411 having an area is a ratio f (L) / f between the F value f (PR) of the rotary parabolic mirror 421 and the focal length f (L) of the main integrated lens 450. It can be said that the image is formed on the surface to be illuminated after being magnified (PR) times. Since the ratio increases from several tens to one hundred times, the image of the light emitting surface of the light emitting diode 411 having a zero-point millimeter-square is projected to a size of several centimeters, and only in this direction (sub-scanning direction) It can be seen that only an efficiency of about 1 to 1/100 is obtained.

  Next, a second example will be described. In this example, the illumination device 400 according to this example includes an LED array 410, a rotating parabolic mirror array 420, a main condenser lens 430, and a main illumination lens 440, and the main integrated lens 470 is replaced with a convex lens as a cylinder lens. Yes. As shown in FIG. 6C, the main integrated lens 470 has the same curvature as the main integrated lens 450 so that the main scanning direction has the focal length of the main integrated lens 450 (L), and the sub-scanning direction. Is assumed to have no optical power.

  In this example, a focusing lens 480 (CL2) is disposed between the main integrated lens 470 and the reading area 460. The converging lens 480 is a cylinder lens, and can be interpreted as a condensing function in the sub-scanning direction separated from L and disposed near the reading region 460. The focal length of the focusing lens 480 is set to f (CL2) = a ′ (see FIG. 6B).

  According to this example, the light beam emitted from the rotating paraboloid mirror array 420 reaches the main illumination lens 440 as a parallel light beam (including a divergent light beam), and the magnification ratio of the light emitting surface of the light emitting diode 411 is a. '/ F (PR), which is several times higher. In other words, the single-digit efficiency is improved over the first example.

  Next, a third example will be described. The illumination device 400 according to this example includes an LED array 410, a rotating paraboloid mirror array 420, a main condenser lens 430, a main illumination lens 440, a main integrated lens 470, and a focusing lens 480, as shown in FIG. In addition, the auxiliary illumination lens 490 (CL3) is disposed. The sub-illumination lens 490 is a cylinder lens, and an image of the light emitting surface of the light emitting diode 411 is formed at the position of the focusing lens 480, and its focal length is f (CL3) = 1 / (1 / a ″. ) + (1 / b ″) (b ″ is the distance from the light emitting diode 411 to the sub illumination lens 490: see FIG. 6D). According to this example, the focal length of the focusing lens 480 is f (CL2). ) = 1 / (1 / a ′) + (1 / a ″) is effective. However, even if f = a ″, the efficiency is slightly worse, but the efficiency is better than the second example. As a result of the experiment, the second example shows an efficiency improvement of about 50% compared to the third example. .

  In each of the above examples, the illuminance distribution in the sub-scanning direction of the reading area reflects the light distribution characteristics of the light emitting diode shown in FIG. 7, so that when obtaining a black and white image, the center of the CCD line sensor of one line at its peak. However, when a three-line CCD is used to obtain a color image, when one color is matched to the peak as shown in FIG. 8A, the other two colors are arranged where the amount of light has dropped. It will be. This difference in the amount of light can be corrected by changing the amplification factor electrically after being read by the CCD, but it is more effective to optically compensate for the difference in the amount of light, as shown in FIG. Lighting efficiency is also improved.

  Next, the 4th example of an illuminating device is demonstrated. FIG. 9 shows a lighting device according to a fourth example, wherein (a) is a plan view of the lighting device, and (b) is a front view of the lighting device. This illuminating device 500 employs an LED array 510 in which light emitting diodes arranged in a row are arranged in three rows in the sub-scanning direction. Further, in this example, the optical axis in the main scanning direction is shifted from the optical axis of the reading system, and competition with the imaging lens is avoided in that direction. As in the third example, the illumination device 500 includes an LED array 510, a rotating parabolic mirror array 520, a main condenser lens 430, a main illumination lens 540, a main integrated lens 550, a sub-illumination lens 560, and a sub-integrated lens. 570 and a focusing lens 580 are provided to illuminate the illumination area 590.

In this example, the line sensor imaging device 20 that reads an image of the original 30 for each of R, G, and B colors and converts the image into an electric signal corresponds to the CCD sensor for each of R, G, and B colors in the sub-scanning direction. Are arranged in three rows.

  The sub-illumination lens 560 (CA4) is a cylinder lens array in which three cylinders having a focal length f (CA4) = b ″ are arranged. The sub-integrated lens (CL4) is light of each cylinder of the sub-illumination lens 560. The axes are matched on the main illumination lens 540 and the focal length is f (CL4) = a ″.

  The combined focal length of the sub illumination lens 560 and the focusing lens 580 is the same as the sub illumination lens 490 (CL3) in FIG. 6D described above, and the focal length f (CL3) = 1 / (1 / a ″) + (1 / b ″) (b ′ is negligibly small).

  By doing this, the illuminance distribution in the sub-scanning direction of the reading region can shift the illuminance distribution peak of each color of R, G, B as shown in FIG. 8B, and the peak position is the position of the 3-line CCD. If it is relatively matched, the efficiency can be the best.

  FIG. 10 shows the main optical components in three dimensions. (A) is a perspective view of a main condenser lens (CA1) and a main integrated lens (CA2), and (b) is a perspective view of a sub illumination lens (CL3). FIG. 7C is a perspective view of the main integrated lens (CL1) shown in FIG. (D) is a perspective view of a focusing lens (CL2). (E) is a perspective view of a focusing mirror when the function of the focusing lens (CL2) is changed from a lens to a reflecting mirror. (F) is a perspective view when the main integrated lens (CL1) is a Fresnel lens. In addition, when the cylinder lens shown in FIG. 10C is made into a Fresnel lens, the range indicated by * in the figure is used.

  Next, a fifth example of the lighting device will be described. 11A and 11B are diagrams showing a lighting device according to the fifth example, in which FIG. 11A is a plan view showing a defect of the lighting device, and FIG. 11B is a plan view of the lighting device according to the fifth example. In this example, direct reflected light is avoided. In the illuminating device shown in FIG. 11A, two illumination units 610 and 620 are arranged with the imaging lens 21 to the line sensor imaging element 20 interposed therebetween, and the main optical axes are made to coincide with each other in the sub-scanning direction. . In such an illuminating device, as shown in FIG. 11A, the illumination light of the two illumination units 610 and 620 is regularly reflected on the surface of the contact glass 124 and directly enters the imaging lens 21. White stripes may be superimposed on the image read by the line sensor imaging element 20. In this case, white streaks appear as many as the number of LEDs.

  Therefore, in the fifth example, as shown in FIG. 11B, the sub-scanning direction is kept the same while avoiding it. That is, in the illuminating device 700 according to this example, the main optical axes (centers of the main integrated lenses) of the illumination units 710 and 720 are aligned with the position of ¼ of the reading area on the opposite side across the main optical axis of the reading system. I have to. In this case, the area illuminated by one illumination unit is half of the entire area, and two illumination units must be used. In this example, the light beam from any LED does not directly enter the imaging lens 21, and the occurrence of the above-described white streak can be prevented.

  Here, the necessary range of the turning mirror will be described. Since the distance from the document surface to the reading unit or from the illumination unit to the document surface is several tens of centimeters, it is necessary to fold the optical path with a plurality of mirrors in order to achieve compactness. In that case, the width dimension required for the mirror is determined by the arrangement position of the mirror as shown in FIG.

  In the example shown in FIG. 12 (a), the size of the reading area in the sub-scanning direction in the reading system is several tens of microns, so in this case, it can be easily ignored if viewed as a triangle similar to the base of the imaging lens aperture. is there. The closer to the document surface may be narrower, but the closer to the imaging lens, the wider the width required. On the other hand, the example shown in FIG. 12B corresponds to the example shown in FIG. 6B in the illumination system, but a portion that diverges at the divergence angle θL is added to the opening of the illumination unit. This is opposite to the reading system and may be narrower closer to the illumination unit, but requires a width closer to the document surface up to the collective lens. This is not the case unless the luminous flux is used efficiently.

  If a large number of light emitting diodes are arranged in the main scanning direction, the main integrated lens becomes large. Actually, there is no problem in optically extending to the width of the apparatus, but as the width is increased, the thickness (in the main optical axis direction) increases and the weight increases. Therefore, a Fresnel lens is formed as shown in FIG. By doing so, an increase in weight can be suppressed, so that inertia can be suppressed when mounted and moved on a traveling body described later, and speeding up is not hindered.

  The present invention is applied to the image reading apparatus of the illumination device as described above. When the present invention is applied, the image reading system is the same as that shown in FIGS.

  First, the first embodiment will be described. FIG. 13 is a front view showing the image reading apparatus according to the first embodiment. An image reading apparatus 800 according to this example is the same as the image reading apparatus 200 shown in FIG. That is, in 800, a first traveling body 810 has a turning mirror 811 and a focusing mirror 812, and a second traveling body 820 has turning mirrors 821 and 822. The line sensor imaging device 20 and the imaging lens 21 are attached to the same member, and the illumination optical axis 841 and the reading optical axis 842 are associated with each other. The illumination device 10 can be moved in the front-rear direction (arrow a in the figure) and the vertical direction (arrow b in the figure) with respect to the reading optical axis, and the reading focal position 831 and the illumination focal position 832 can be made to coincide. Yes. The lighting device 10 is slidably disposed on the base and is fixed at a predetermined position by fastening means such as screws. Note that a moving screw or the like of the illumination device 10 can be provided so that the illumination device 10 can be moved slightly.

  Next, a second embodiment will be described. FIG. 14 is a front view showing an image reading apparatus according to the second embodiment. The image reading apparatus 850 according to this example is the same as the image reading apparatus 300 shown in FIG. That is, in 900, the lighting device 10, the line sensor imaging device 20, the focusing mirror 861, and the deflecting mirrors 862 and 863 are arranged on one traveling body 860. In addition, the imaging lens 21 is disposed on the traveling body 860, and a plane mirror portion 865 for imaging is disposed on the focusing mirror 861. In addition, the illumination device 10 can be adjusted in the focusing mirror 861 in another example in which the illumination device 10 is arranged to be movable.

  The adjustment of the focusing mirror 861 can be performed by providing an angle adjusting mechanism for adjusting the mounting angle of the reflecting mirror, and can also have a position adjusting mechanism for adjusting the mounting position of the focusing mirror 861.

  Next, an embodiment of a method for adjusting the image reading apparatus will be described. This adjustment is for the lighting device of the second embodiment. In this case, the angle of the focusing mirror 861 and the mounting position are changed, and the lighting device is adjusted by the following method. It is assumed that the relationship between the illumination focus position and the reading focus position does not move after the illumination focus position is adjusted and fixed.

  In this example, as shown in FIG. 15, first, an illuminance meter 880 is installed at the reading position so that the illuminance at the ideal reading focus position 872 can be measured with a jig or the like, and the illumination device 10 is moved. Adjust until the specified illuminance is reached. At this time, it is desirable to install a plurality of illuminometers in the main scanning direction and measure a plurality of points.

  Thereafter, the illuminance meter used for the measurement is removed, and as shown in FIG. 15, the illumination light emitted from the illumination device 10 is applied to the reading characteristic value adjusting jig chart 890, and the reflected light is applied to the line sensor imaging device. 20, the read data is analyzed by the data processor 900, and an adjustment value is determined.

  In addition, after adjusting the reading characteristics with a light source different from the illumination device 10, the illumination focal point position can be adjusted using data from the image sensor. In this case, after adjusting only the image sensor output level of the reading characteristic with another light source (reading system temporary adjustment), the position of the illumination focus of the illumination device is adjusted using the data from the line sensor image sensor 20, and then The main adjustment of the reading system can be performed.

  Next, a second embodiment relating to the adjustment method of the image reading apparatus will be described. FIG. 16 is a front view illustrating the adjustment method of the image reading apparatus according to the second embodiment. In this example, the traveling device 960 of the illumination device 950 includes the illumination device 10 in addition to the line sensor imaging element 20 and the imaging lens 21. Further, the traveling body 960 is provided with turning mirrors 964 and 965 and a focusing mirror 966 on the optical path of the other illumination device 10, and the light from the focusing mirror 966 is focused on the illumination focal point 832. Further, the image at the reading focal position is focused by the imaging lens 21 through the deflecting mirrors 961, 962, and 963, and formed on the line sensor imaging device 20.

  In the adjustment method according to the first embodiment, since only the reading system (imaging device, imaging lens, and the illumination device) is attached to the same member, it has only to be associated with each other. However, in such an illuminating device 950, it is necessary to associate the posture of the focusing mirror 966 in addition to the reading system and the illumination system. The light emitted from the illumination device 10 is turned back by the turning mirror 964 and the turning mirror 965, reflected and collected by the focusing mirror 966, and illuminates the illumination focal position 972. In this example, the position of the focusing mirror 966 can be adjusted, and the illumination position is adjusted. Either or both of the turning mirror 964 and the turning mirror 965 are adjusted, and the illumination position is adjusted by the method described above.

  Next, the adjusting mechanism for the focusing mirror 861 and the focusing mirror 966 will be described. FIG. 17 is a perspective view showing a first example of the adjusting mechanism of the focusing mirror. The concave mirror 1101 showing the focusing mirror 861 and the focusing mirror 966 is rotatably fixed to the side wall 1102 by the adjusting mechanism 1100. The concave mirror 1101 is provided with a shaft 1103 that serves as a rotation reference, and the concave mirror 1101 is rotatably held on the side wall 1102 (arrow 1105). The concave mirror 1101 can change the angle to the side wall 1102 to a predetermined angle by loosening the fastening member 1104 disposed in the arcuate hole 1106 at the time of adjustment, and is fixed to the side wall 1102 by the fastening member 1104 after the adjustment is completed. . With such a mechanism, the illumination focus position can be adjusted by changing the mounting angle of the focusing mirror 861 and the focusing mirror 966.

  Similarly, as the adjusting mechanism for the focusing mirror 861 and the focusing mirror 966, the following configuration can be adopted. FIG. 18 is a perspective view showing a second example of the adjusting mechanism of the focusing mirror. The concave mirror 1201 showing the converging mirror 861 and the converging mirror 966 is fixed to the side wall 1102 by the adjusting mechanism 1200 so that the mounting position is variable. The concave mirror 1201 is provided with two pins 1203 at one end thereof, and the pins 1203 are held so as to be movable within the long hole portion 1206 of the side wall 1202 (arrow 1205). At the time of adjustment, the concave mirror 1201 can be moved horizontally to a predetermined position by loosening the fastening member 1204 disposed in the elongated hole 1207, and is fixed to the side wall 1202 by fastening the fastening member 1204 after the adjustment is completed. With such a mechanism, the illumination focus position can be adjusted by changing the mounting positions of the focusing mirror 861 and the focusing mirror 966.

  In this example, the concave mirror 1201 moves in the horizontal direction. However, the moving direction may be vertical or oblique. In each of the above examples, a shaft, a pin, and a fastening member are arranged directly on the concave mirror to enable rotational movement. However, a separate mechanism that allows the concave mirror to rotate is provided between the concave mirror and the side wall. it can.

1 is a cross-sectional view conceptually showing an image forming apparatus such as an electrophotographic copying machine or printer according to the present invention. 1 is a perspective view illustrating an overall configuration of an image reading apparatus according to a first example. FIG. 3 is an enlarged front view showing a main part of the image reading apparatus shown in FIG. 2. It is a perspective view which shows the whole structure of the image reader which concerns on a 2nd example. FIG. 5 is an enlarged front view showing a main part of the image reading apparatus shown in FIG. 4. It is a figure which shows the 1st thru | or 3rd example of an illuminating device, (a) is a top view common to the 1st thru | or 3rd example, (b) is an enlarged front view of a 1st example, (c) is 2nd. The enlarged front view of the example of (d) is an enlarged front view of the third example. It is a graph which shows the light emission characteristic of a LED light emitting element. It is a graph which shows the model of the illumination distribution state of the subscanning direction of an illuminating device. It is a figure which shows the illuminating device which concerns on a 4th example, (a) is a top view of an illuminating device, (b) is a front view of an illuminating device. The main optical parts are shown three-dimensionally. It is a figure which shows the illuminating device which concerns on a 5th example, (a) is a top view which shows the malfunction of an illuminating device, (b) is a top view of the illuminating device which concerns on a 5th example. It is a figure which shows the arrangement | positioning state of a mirror, (a) is a schematic diagram which shows a reading system, (b) is a schematic diagram which shows an illumination system. 1 is a front view illustrating an image reading apparatus according to a first embodiment. It is a front view which shows the image reading apparatus which concerns on a 2nd Example. It is a front view which shows the test method of the image reading apparatus which concerns on a 1st Example. It is a front view of the image reading apparatus which shows the test method of the image reading apparatus which concerns on 2nd Example. It is a perspective view which shows the 1st example of the adjustment mechanism of a focusing mirror. It is a perspective view which shows the 2nd example of the adjustment mechanism of a focusing mirror.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Illumination device 12 Image formation part 20 Line sensor image pick-up element 21 Imaging lens 23 Imaging area 24 Motor 25 Transmission means 30 Original document 31 Original surface 111 Unit 112 Image formation part 113, ADF113 Automatic document feeder (ADF)
114 Document discharge trays 115 to 118 Paper feed cassette 119 Paper feed unit 120 Paper discharge tray 121 Document stand 122 Pickup roller 123 Document transport belt 124 Contact glass 125 Reading device 126 Light source 127 Optical system 128 Photoelectric conversion element 130 Photoconductor 131 Charging device 132 Unit 133 Developing Device 134 Transfer Device 135 Cleaning Device 137 Discharge Roller Pair 140 Fixing Device 200 Image Reading Device 210 First Traveling Body 211, 221, 222 Turning Mirror 212 Converging Mirror 220 Second Traveling Body 221, 222 Turning Mirror 300 Image reading device 310 Traveling body 312 Focusing mirror 313 Turning mirror 314 Turning mirror 315 Correction lens 316 Plane mirror unit 400 Illuminating device 410 LED array 411 Light emitting diode 420 Rotating parabolic mirror array 421 Rotating Object mirror 430 Main condensing lens 440 Main illumination lens 450 Main integration lens 460 Reading area 470 Main integration lens 480 Condensing lens 490 Sub illumination lens 500 Illumination device 510 LED array 520 Rotating paraboloid mirror row 540 Main illumination lens 550 Main integration Lens 560 Sub-illumination lens 570 Sub-integration lens 580 Condensing lens 590 Illumination area 610, 620 Illumination unit 700 Illumination device 710, 720 Illumination unit 800 Image reader 810 First traveling body 811 Turning mirror 812 Converging mirror 820 Second traveling body 821 , 822 Turning mirror 831 Reading focus position 832 Illumination focus position 841 Illumination optical axis 842 Reading optical axis 850 Image reading device 860 Traveling body 861 Focusing mirrors 862 and 863 Turning mirror 865 Plane mirror portion 872 Reading focus position 880 Illuminometer 890 Reading Data value adjustment jig chart 900 Data processing device 950 Illumination device 960 Traveling body 961, 962, 963 Direction mirror 964, 965 Direction mirror 965 Direction mirror 966 Focusing mirror 972 Illumination focal position 1100 Adjustment mechanism 1101 Concave mirror 1102 Side wall 1103 Shaft 1104 Fastening member 1105 Arrow 1200 Adjustment mechanism 1201 Concave mirror 1202 Side wall 1203 Pin 1204 Fastening member 1205 Arrow 1206 Long hole

Claims (13)

A light source, and a plurality of illumination lenses, comprising: an illumination device that divides a light beam emitted from the light source into a plurality of light beams by the illumination lens and irradiates the divided light beams in a superimposed manner on a document surface;
Reflected light from the original illuminated by the illuminating device is imaged on an image sensor by an imaging lens, and the original is read in a sub-scanning direction orthogonal to the main scanning direction while being read linearly in the main scanning direction. In an image reading apparatus for reading a typical image,
An image reading apparatus characterized in that a focal position of the illumination device can be adjusted.   The image reading apparatus according to claim 1, wherein the position of the illumination device is variable, and the position of the illumination device is adjusted so that the illumination focus position matches the reading focus position.   The image reading apparatus according to claim 1, further comprising a reflecting mirror having a function of focusing illumination light, wherein the reflecting mirror is adjustable.   The image reading apparatus according to claim 1, further comprising an illumination light reflecting mirror, wherein the reflecting mirror is adjustable.   5. The image reading apparatus according to claim 3, wherein the reflecting mirror has an angle adjusting mechanism for adjusting a mounting angle of the reflecting mirror.   The image reading apparatus according to claim 3, wherein the reflecting mirror includes a position adjusting mechanism that adjusts a mounting position of the reflecting mirror.   An image forming apparatus comprising the image reading apparatus according to claim 1. A light source, and a plurality of illumination lenses, comprising: an illumination device that divides a light beam emitted from the light source into a plurality of light beams by the illumination lens and irradiates the divided light beams in a superimposed manner on a document surface;
Reflected light from the original illuminated by the illuminating device is imaged on an image sensor by an imaging lens, and the original is read in a sub-scanning direction orthogonal to the main scanning direction while being read linearly in the main scanning direction. In an adjustment method of an image reading apparatus for reading a typical image,
A method for adjusting an image reading apparatus, comprising adjusting a focal position of the illumination device.   9. The method of adjusting an image reading apparatus according to claim 8, wherein when the focus position of the illuminating device is adjusted, whether or not the adjustment value is correct is determined using an illuminometer.   An adjustment method for an image reading apparatus, wherein after adjusting the illumination focal position according to claim 9, the reading characteristic is adjusted using the illumination light.   9. The method of adjusting an image reading apparatus according to claim 8, wherein when the focus position of the illumination device is adjusted, an image sensor is used to determine whether the adjustment value is correct or not.   12. An adjustment method for an image reading apparatus, comprising: adjusting an illumination focal position after adjusting a reading characteristic value by an adjustment method according to claim 11.   An image reading apparatus comprising: adjusting an illumination focus position after adjusting a predetermined characteristic of the read characteristic by the adjustment method according to claim 11; and re-adjusting the read characteristic with the illumination light having the illumination focus adjusted. Adjustment method.