JPS60253367A - Color original reader - Google Patents

Abstract

PURPOSE:To attain the optional control of the color balance of a color original by revolving the 1st and 2nd dichroic mirrors and a compensator in the same direction and at the same angle within each face and at the same time revolving the 1st and 2nd solid state image sensors in the same direction at an angle double as large as the rotary displacement angle. CONSTITUTION:The 1st dichroic mirror 2 set so as to secure an incident angle theta for the light on an optical axis OA within a radial face is turned at an angle theta toward the 1st solid-state image sensor 10 in the radial face. Under such conditions, the sensor 10 is turned by 2alpha from its reference of theta(=45 deg.) to secure the correct image formation. Each output of a high or low level is supplied to AND gates 33-36 respectively together with the pulse signal given from an oscillator 32. Then the 1st and 2nd step motors 39 and 40 are rotated right or left according to the signal level via motor driving circuits 37 and 38. Thus the white balance is controlled with a color original.

Description

Detailed Description of the Invention (Technical Molecule f) This invention relates to a device for high-speed reading of color originals in 7-color copying machines, digital color copying machines, etc. (Prior art) A color original is separated into the three primary colors of blue, red, and green by a color separation optical system, and each is read by a solid-state image sensor such as a camera tube or CCD.

As a color separation optical system, a one-way separation method using prisms, which is used in broadcasting 3P color cameras, is known, but this method requires difficult positioning accuracy and fixing methods for the prisms, and also requires processing accuracy. It is expensive because of the strict requirements, and it is also very difficult to adjust the digits of the light-receiving element. In a color separation optical system using a dichroic ink mirror, it is necessary to use a relay lens to remove astigmatism caused by the dichroic mirror, which makes the structure complicated and the optical system such as lenses and mirrors Since the number of elements increases, there is a large loss of light quantity, and it is necessary to be careful about the occurrence of ghosts due to flare.

JP-A-54-48258 discloses a color separation optical system using a dichroic mirror that eliminates astigmatism through a sl/-1/ lens. This is the 9th
As shown in FIG. 10, a first parallel plane substrate 1
The first dichroic mirror 2 formed on one side of the substrate and the thickness of 1/2 of this first parallel plane substrate 1? A second dichroic mirror 5 formed between second, third, and parallel plane substrates 3 and 4, respectively, is provided, and the second dichroic mirror 5 is irradiated with incident light that has passed through the first dichroic mirror 2.
dichroic mirror 5 at 90° with respect to the first dichroic mirror 2 about the optical axis OA of the incident light
It is arranged in a rotated position.

The first and second dichroic mirrors 2 and 51 are each tilted by the same angle of 45 degrees with respect to the optical axis OA. For convenience of explanation, in FIG. 7, a surface parallel to the plane of paper is a radial plane, and in FIG. 8, a plane parallel to the plane of paper, that is, perpendicular to the radial plane, is a tangential plane.

When such a color separation optical system is used to configure a line-scanning original document handling device, the light source 6 illuminates the document in a slit shape and moves the color document 8 in the direction of the arrow e on the document table glass 7. After passing through the lens 9, the red component light passes through the first dichroic mirror 2.
reflected by the first 1-i1 body image set
When 0 VC is input, one red component image is read by the eye's self-scanning. The light transmitted through the first dichroic mirror 2 then enters the second dichroic mirror 5.
The blue component light is reflected and the green component light transmitted through the second solid-state image sensor II color 5 enters the third solid-state image sensor 12, where a green component image is read.

The light transmitted through the first dichroic ink mirror~2 is
Although astigmatism is caused by passing through the parallel plane substrate I of the second dichroic mirror 5, both of the parallel plane substrates 3 and 4I on both sides of the second dichroic mirror 5 pass through the parallel plane substrate 3 twice. As a result, the light transmitted through the second Kreuzk mirror 5 is transmitted to the planar substrates 3 and 4.
by passing through the respective first parallel plane substrates 1
The astigmatism caused by this will be reversely corrected.

However, a problem with the document handling device having such a configuration is the ghost image that appears on the second solid-state image sensor 11. A ghost image also appears on the first solid-state image sensor 10 due to reflection from the back surface of the first parallel substrate 1, but this is because a ghost image S,1 appears parallel to the normal image S1 as shown in FIG. There is no problem with reading, but the ghost image that appears on the second solid-state image sensor 11 is a ghost image caused by surface reflection of the second parallel substrate 3 on the same line as the normal image S2, as shown in FIG. 1182' will appear slightly shifted to the left, and the ghost image 82'1 due to reflection from the back surface of the third parallel substrate 4 will appear slightly shifted to the right, making it impossible to read the signal correctly.

Therefore, the applicant of the present application previously proposed a four-lateral reading device in %tonsho No. 58-177486 which prevents malfunctions in signal reading due to such a ghost image on the second solid-state image processor. As shown in FIGS. 13 and 14, the configuration is as shown in FIGS. , but the second dichroic mirror I4 (well, the first parallel substrate l
It is formed on the surface of the 2,000-th row planar substrate 13 made of the same material and of the same thickness, and is arranged in a posture that extends 90'1 lal around the optical axis OA. Further, between the second dichroic mirror 14 and the second solid-state image sensor 11, a compensator 15, which is a parallel plane plate made of the same material and of the same thickness as the second parallel thousand plane substrates 1 and 13, is installed. 2 is arranged parallel to the dichroic mirror 14. Each parallel plane substrate 1.13 and compensator 151'! ,
The optical axis O is adjusted so that the angle of incidence on the optical axis OA is the same θ in the radial plane and in the tangential plane, respectively.
It is placed at about 1 point relative to A. The first dichroic mirror 2 is a red reflective mirror, but it can also be a blue reflective mirror. In this case, the second dichroic mirror 14 is a red reflective mirror.

The light beam including astigmatism that has passed through the first parallel plane substrate 1 is
A part of it is reflected by the second dichroic mirror 14,
By passing through a compensator 15 rotated by 90° around the optical axis OA with respect to the first parallel plane substrate l, astigmatism of equal amount and opposite sign is generated and corrected, and the second
The light enters the solid-state image sensor/system 11. The light beam transmitted through the second dichroic ink mirror 14 passes through the second parallel plane substrate 13 in a concave manner, so that astigmatism is corrected, and then enters the third solid-state image sensor 12. To avoid the incidence of a ghost image on the second solid-state image sensor 11 due to reflection from the back surface of the second parallel substrate 13, the compensator 15 should have spectral characteristics by allowing only the reflected light from the second dichroic ink mirror 14 to pass therethrough. Beta marked.

(Object of the invention) The object of the invention is to solve the following problems based on the prior invention:
An object of the present invention is to link an improved color document reading device capable of reading a color document while arbitrarily adjusting the color balance thereof.

(1h of the Invention) The color document reading device according to the present invention has first and second
Rotate the dichroic ink mirror and compensator in the same direction and at the same angle in their respective planes, and set the first and second solid images 7''!l + 2 for their rotational displacement. Includes a configuration in which the first and second dichroic mirrors are rotationally displaced in the same direction at twice the angle.By rotating and displacing the first and second dichroic mirrors, their spectral characteristics can be changed, so the color balance of color originals can be adjusted arbitrarily. Be able to change and read it.

As shown in FIG. 1, a first dichroic mirror 2 arranged so that the incident angle of light on the optical axis OA is θ in a radial plane is connected to a first solid-state image sensor in a radial plane. When the first solid-state image sensor 10 is rotated by an angle α toward the 10 side, the first solid-state image sensor 10 is moved 2
If the rotation is displaced by α in the same direction, the reflected light from the first dichroic ink mirror 2 will be reflected from the first solid-state image sensor lO
It is possible to perform correct imaging by entering the image at a right angle to the upper G''.Similarly, as shown in FIG. When the second solid-state image sensor 11 is rotationally displaced by an angle α, if the second solid-state image sensor 11 is rotationally displaced from its initial position by 2α in the same direction, the reflected light from the second dichroic mirror 14 is transferred to the second solid-state image sensor 11. 11 at right angles to form a correct image.

Thus the first and second dichroic mirrors 2.1
If the angle of incidence of 4 is changed, its spectral characteristics will change. For example, if the first dichroic mirror 2 reflects blue light, as shown in FIG. '#: Custom made approximately 60mμ short wave E, +III
Henft. Furthermore, if the second dichroic mirror 14 reflects red light, as shown in FIG. Culm shortwave J (K1j to 1n7
to Therefore, by displacing the first and second dichroic mirrors 2 and 14 in the same direction and with the same circularity by 11], the spectral characteristics can be changed to the same degree. You can change the balance arbitrarily. For example, if you want to reproduce a reddish color original in a standard color and dark color, move the J and second dichroic mirrors 2 and 14 to their standard positions.
It is sufficient to shift the spectral characteristics toward the shorter wavelength side by rotationally displacing it in the direction in which the incident angle θ increases from 5°. If you want to reproduce a slightly bluish color original in a standard color tone, use the first and second graphical mirrors 2.
．． 14 may be rotationally displaced from its reference position of 45° in a direction in which the incident angle θ becomes smaller, thereby shifting its spectral characteristics to the longer wavelength side.

Figure 5 shows an example of a mechanism for performing such rotational displacement. The second dichroic mirror 14 is rotatably driven by a second step motor 16 about its reflection point on its optical axis.
It is fixed to via a receiving member 18. A first gear 19 is fixed to the motor rotation shaft 17, and a second gear 21 fixed to another rotation shaft 20 meshes with this gear 19. A third gear 22 is fixed to this another rotation 1 k 20, and a fourth gear 24 fixed to a bearing 23 that is reliably attached to the motor rotation shaft 17 is connected to the third gear 22K. They mesh together. 4th gear 24
In K, the base of the arm 25 is fixed to the bearing 23 as a common rotating shaft, and the rotating shaft 2 is fixed to the middle part of the arm 25.
6 and the receiving member 27, the convencator 5 is
It is mounted so that it can rotate around the reflection point on its optical axis. A second fixed image sensor 11 is fixed to the distal end of the arm 25 via a support 28 on a straight line passing through the centers of the motor rotation shaft 17 and the convencator rotation shaft 26. Second dichroic mirror 14
When the second dichroic mirror 14 and the height/henseater 15 are in parallel, one discharge end of the receiving member I8 and the receiving member 27 for the convencator 15 are connected to the motor rotation l111117 and the convencator rotation #. Connecting piece 29 at a position equal to the center distance # of ql126
is connected to the recirculation function.

Since the ratio of the number of teeth between the first gear 19 and the fourth gear 24 is set to 2:1, when the second dichroic ink mirror 14 rotates around the motor rotation shaft 17 by the necessary amount, the second solid The image sensor 11 is also the motor rotation shaft 17.
Rotate around twice that angle. Also, the motor rotation shaft 17. Convencator rotation shaft 26 and support 2
8 are located on the same straight line, and the second dichroic mirror 1
4 and the compensator 15 constitute a parallel link mechanism together with the arm 25 and the connecting piece 29, so that the optical axes can be moved in parallel to each other without shifting, and the incident light on each optical axis can be kept the same. Stone formed.

Note that the rotational displacement of the first dichroic mirror 2 and the first solid-state image sensor 10 is the same as that of FIG. 3 with the compensator I5 and its attached V% ft/f component removed, and a motor or synchronously driven by the same motor.

FIG. 6 shows a block diagram of an example of a control circuit for driving and controlling such a rotational displacement mechanism. The eleventh salary image sensor 10 receives blue reflected light,
A signal with a level corresponding to the amount of incident light is output. Second
The solid-state image sensor 11 receives the red reflected light and similarly outputs a signal of 1 nohel corresponding to the amount of the incident light. Signals from these sensors 10 and 11 are input to window comparators 30 and 31, respectively, to set reference values Vr and ef.
l, 2, and when the human input signal is sharper than the reference value V, -t or v3, the output of Vci is high level ++
1, and when the input signal is smaller than the reference value V2 or V4, the low level output becomes 1. Also, Vl
〉Human Power No. 1B〉If it is v2, both the high level output and the low level output will be +10. In this way, each window comparator 30, 31 obtains the reference value vref' +
2 by comparing each solid-state image sensor 10,
It becomes possible to judge the 17th bell of the output No. 1d from No. 11.

Each one novel dog or level small output is output from each AND gate 33.34.3 along with pulse number 716 from oscillator 32.
5.36 and motor drive circuit 37.3, respectively.
8, the first step motor 39 and the second step motor 40 are rotated clockwise or counterclockwise depending on the '1 symbol level, thereby adjusting the white balance of the color original.

FIG. 7 shows an example of a control block diagram in the case where one color novel is adjusted manually rather than automatically. In this case, you will need to check the tone of the reproduced color image before making the adjustment, but since the reproduced color image is based on the signal level from each solid-state image sensor, such manual adjustment is not necessary. In the end, it depends on the signal level from the solid-state image sensor. The pulse signal from the oscillator 41 is input to the control circuit 42 while the clockwise switch 43 or counterclockwise switch 44 connected to the control circuit 42 is kept on, and the motor drive circuit is activated according to the number of pulses. 45 is driven synchronously with the first step motor 39 and the second step motor 4DQ, and the rotational displacement thereof is displayed on the angle display device 46. For example, if the 1 crotter signal now corresponds to a 1st quad displacement angle of 1° K, the first step is to keep the clockwise switch 43 on and output 8 pulses as shown in Fig. 8. The motor 39 and the second step motor 4o rotate the reference position of 45° clockwise by 8°, and the angle display device 46 visually displays 8°. Next, the first switch 44 is turned on and the pulse signal is output for 10 seconds.
The step motor 34 and the second step motor 4o are displaced 100 degrees counterclockwise from the previously displaced position of 8 degrees, and -2 degrees is displayed on the display device 46. In this way, manual color level adjustment is performed.

(Effects of the Invention) As described above, the color document reading device according to the present invention has the following features:
The first and second dichroic mirrors and the convenosator are rotated in the same direction and at the same angle within their respective planes, and the first and second solid image sensors are Since the image sensor is rotated in the same direction at twice the angle of rotation, it is possible to read a correct signal that corrects astigmatism and ghost images caused by the dichroic mirror, and also to correct the spectral characteristics of the dichroic mirror. By changing the color level, you can read or print color originals at any color level.

[Brief explanation of drawings]

FIG. 1 is a layout diagram of the main optical system in a radial plane of a color document reading device showing an embodiment of the present invention, and FIG.
Main optical system layout diagram in the tangential numerical plane perpendicular to the figure,
Figure 3 is a spectral characteristic diagram of the blue reflective dichroic mirror at different angles of incidence, Figure 4 is a spectral characteristic diagram of the red reflective dichroic mirror at different angles of incidence, and Figure 5 is
FIG. 6 is a block diagram showing an example of the control method according to the present invention, and FIG. 7 is a schematic diagram showing an example of the rotational displacement mechanism according to the present invention. 8 is a timing diagram for the control method shown in FIG. 7, and FIG. 9 is an optical system arrangement in a radial plane showing an example of a color original reading device using a conventional dichroic mirror. Figure 10 is the 9th
Figure 1 shows the arrangement of the optical system in the tangential plane of the device.
Figure 1 shows the first part of the apparatus shown in Figures 9 and 10.
FIG. 12 is a diagram showing the imaging state on the solid-state image sensor, and FIG. 13 is a diagram showing the imaging state on the second solid-state image sensor in the apparatus shown in FIGS. 9 and 10. FIG. 14 is a diagram showing the arrangement of the optical system in the tangential plane in the prior invention shown in FIGS. 1 and 13. 9... Imaging lens, 2... First dichroic mirror, 1o... First solid-state image sensor, 1
1...Second solid-state image sensor, 12...Third solid-state image sensor, 14...Second dichroic mirror~, 15...Convencator% I () [1 Ryo 2 Figure/Flood δ 2

Claims (1)

[Claims] An apparatus for reading a color original by color-separating the color original into three primary colors through an imaging lens and a color separation optical system and forming images on first, second, and third solid-state image sensors, respectively, the apparatus comprising: A color separation optical system includes a first dichroic mirror with surface reflection arranged so that the incident angle on the optical axis is θ in a radial plane, and a first dichroic mirror with a surface reflection arranged so that the incident angle on the optical axis is θ in a radial plane, and a first dichroic mirror with a surface reflection arranged so that the incident angle on the optical axis is θ in a radial plane, a second surface-reflecting dichroic ink mirror arranged so that the incident angles of the second dichroic ink mirrors are the same θ; a compensator disposed parallel to the second dichroic mirror between the two dichroic mirrors and a second solid-state image sensor that receives reflected light therefrom; a compensator disposed in parallel with the second dichroic mirror; Rotatably displace the compensators in the same direction and at the same angle in each plane, and
means for rotationally displacing the first solid-state image sensor and the second solid-state image sensor that receive reflected light from the dichroic mirror in the same direction at an angle twice as large as the degree of rotational displacement;
A color original reading device comprising: a control means for controlling the rotational displacement means to sound in accordance with a signal 1 novel from the first and second solid-state image sensors.