JPH02277019A - Color separation type optical scanner - Google Patents

Abstract

PURPOSE:To realize the color separation type optical scanner which securely and easily perform color separation and optical scanning by providing an optical filter which has wavelength selectivity on each light beam reflecting surface of a rotary polygon mirror used for the optical scanner. CONSTITUTION:Color filters of red(R), green(G), and blue(B) are provided on the respective reflecting surfaces of the rotary polygon mirror 2 in order. This rotary polygon mirror 2 is rotated and the light from the white light source 1 is guided to the respective reflecting surfaces to obtain scanning light beams of R, G, and B by the light beam reflecting surfaces. A document 3 is therefore irradiated with the light beams which are colored in red, green, and blue in order and the light beams are converged by an optical system 4 such as a lens mirror and made incident on a CCD array; 5. Consequently, the need to provide a mechanical optical shutter is eliminated and a switching circuit for a light source need not be provided; and a simple, fast image scanner is obtained by using an optical sensor having no color filter and an easy, fast color printer is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical scanning device using a rotating polygon mirror, and more particularly to a color separation type optical scanning device suitable for use in color image readers and color printers.

[Summary of the invention]

The present invention provides an optical scanning device using a rotating polygon mirror, in which an optical filter having wavelength selectivity is provided on each light beam reflecting surface of the rotating polygon mirror. A scanning device is provided.

[Conventional technology]

Generally, some type of scanning device is required to read or print an image as an electrical signal. It is known to use a rotating polygon mirror as one of the means for scanning a light beam such as a laser beam, and is used in, for example, laser beam printers and barcode leagues.

Further, as a light beam input device, for example, an in-line type CCD (Charge Coupled Device) is used.
ce) Imagers and photoconductor arrays are known, in which the entire surface of the document is irradiated with light, horizontal scanning is performed by electrically switching the CCD or photoconductor, and vertical scanning is performed by electrically switching the CCD or photoconductor. Scanning is often performed by moving the manuscript paper.

Incidentally, in a color imager for reading color information of a color image, it is necessary to obtain color-separated electrical signals, and in a color printer, it is necessary to synthesize and print a color image from the color-separated electrical signals.

For example, a conventional technique of scanning an image while separating colors to obtain color-separated electrical signals will be described using a color image input device using an in-line CCD array as an example.

Figure 3 shows a conventional color image input device [1] in which red (R) and green (G) are displayed on the photosensitive cells of an in-line CCD imager.
Blue (B) or its complementary color cyan (C) magenta (M)
Provide yellow (Y) color filters sequentially or in a predetermined arrangement,
Irradiate a document with white light and use an objective lens to display the CCD
By forming an image on an imager, scanning it electrically, and switching sequentially, it is possible to obtain electrical signals separated into RGB or CMY. This method is C'
It is technically difficult to manufacture a CD imager, and it is difficult to achieve high density and high resolution.Therefore, there are problems in that the unit cost is high and variations are likely to occur for each pixel.

Figure 4 shows a color image input device of conventional example [2], in which instead of providing a color filter for each pixel of the CCD imager,
Color switching is performed by mechanically moving the color filter placed in front of the CCD imager.The entire surface of the document is read with one color filter, then switched to the next filter and read and scanned again from the beginning. Total of 3 same manuscripts
There is a frame switching method that obtains color signals by scanning twice, and a line switching method that obtains color signals by scanning once for each line, and a line switching method that only requires one scan by switching color filters for each line, but both require a color filter switching mechanism and There is a problem in that filter switching takes time.

Figure 5 shows a device that is equipped with a three-color light source without a color filter, and switches the color of the light source.For example, when a fluorescent light is blinked to switch the light source, the green rise time of the fluorescent light is long, and the scanning There is a problem that the total time for the light source is long, and a power switching circuit is required to switch the light source. Another problem is that it is difficult to obtain an appropriate light source that can synthesize natural light using three colors and emit surface light.

Further, since three light sources are required, there is a problem that the device becomes large, and furthermore, when a mechanical shutter method is adopted to avoid blinking of the light sources, there is a problem that becomes even more complicated.

In any of the above-mentioned conventional techniques, color separation and optical scanning cannot be performed appropriately and easily, and therefore color scanners are expensive and have problems in scanning speed and resolution.

Also, in color printers, for example, color-separated electrical signals are printed on print paper four times, RGB and black (combined from RGB). There has been no apparatus suitable for color separation and scanning of the color separated light to obtain a printer that can be converted into a light beam of 1000 nm to print on color photographic paper in a single scan.

That is, although color filters for color separation are known and optical scanning techniques are also known, there is no device that can appropriately and easily perform color separation and optical scanning suitable for color scanners and color printers. Color scanners and printers were expensive, slow, and had low resolution.

[Problem to be solved by the invention]

It is an object of the present invention to solve the problems described in the prior art and to obtain an apparatus for color separation and scanning of color-separated light, which can perform color separation and light scanning reliably and easily.

[Means for Solving the Problems] In the present invention, in an optical scanning device using a rotating polygon mirror, each light beam 1 of the rotating polygon mirror is provided with an optical filter having wavelength selectivity on the reflecting surface. This is a color separation type optical scanning device with the following characteristics.

[Effect]

In the optical scanning device of the present invention, optical filters having wavelength selectivity are sequentially provided on each light beam reflecting surface of the rotating polygon mirror, for example, R, G, B, etc., so that one white light source is provided and the By rotating the polygon mirror, RGB scanning light can be obtained for each light beam reflecting surface.

Therefore, by passing light through the white light source, the rotating polygon mirror, the original, and the dimensional optical sensor in this order, the original is scanned with light separated into RGB, resulting in a color image scanner. Using a light sensor without a color filter, without providing a mechanical light shutter, without providing a switching circuit for the light source,
A simple and high-speed image scanner can be obtained.

In addition, by passing light through a white light source, the rotating polygon mirror, and color photographic paper in this order, colored light beams will sequentially scan the color photographic paper in accordance with color-separated electrical signals, creating a simple and high-speed color printer. Become.

〔Example〕

An embodiment in which the present invention is applied to a color image input device will be described with reference to FIG.

In this example, the light emitted from the white light source 1 is filtered into red (R), green (G), and blue (B) as optical filters with wavelength selectivity.
Alternatively, the light beams are incident on a rotating polygon mirror 2 in which cyan (C), magenta (M), and yellow (Y) color filters are sequentially provided on each reflecting surface, and the light beams are colored, for example, red, green, or blue by the color filters. The light is irradiated onto a document 3, focused by an optical system 4 such as a lens or mirror, and then incident on a CCD array 5. The orientation of the rotating polygon mirror 2 shown in FIG. 1 is suitable for inputting light separated into one color for each pixel into the CCD array 5. On the other hand, in the other embodiment shown in FIG.
The direction and length of the rotating polygon mirror 2 are different compared to the figure.
The same color of red, green, or blue is applied to the CCD array 5 line by line in one scan.

In the embodiments of FIGS. 1 and 2, the rotating polygon mirror has the following features:
Since it is separated into three colors, RGB, it is a polyhedron having an integral multiple of 3 reflective surfaces, and each reflective surface is a mirror surface. Well-known methods such as coating with organic filters such as gelatin or casein, or pasting plastic filters are convenient for providing color filters on the mirror surface, but if the smoothness of the color filter surface is an issue, thin coatings may be used. A glass filter can be attached, and if the color filter needs to be thin and uniform, a method using light interference such as a multilayer film of oxide, nitride, or fluoride can also be used.

The rotation (scanning speed) of the rotating polygon mirror 2 and the CCD
By synchronizing the signal switching speed of the array 5, color-separated image signals can be obtained from the CCD array 5. Although not mentioned above, the feeding of manuscript 3 (
Needless to say, sub-scanning) is also performed sequentially.

In the above embodiments, the case of a color image human-powered device has been described. For example, in FIG. CC
If the D array 5 is replaced with a servo sensor such as an autofocus sensor, a color printer will be obtained. In this case, it goes without saying that the brightness of the light source, scanning speed, etc. should be set so as to obtain an exposure time suitable for the sensitivity of the photographic paper.

Although the case of a three-color image has been described above, the same applies to the case of a two-color type, such as a red-green glasses-type three-dimensional image printer.

Furthermore, in the case of scanning laser beams of a plurality of wavelengths, by matching the characteristics of the color filter to the wavelength of the laser beams, scanning can be performed with wavelengths selected at each moment. In this case, especially when it is necessary to continuously control the output of the laser beam, there is no need to intermittent the laser beam, so that the control can be performed stably.

(Effects of the Invention) By implementing the present invention, an optical scanning device that can reliably and easily perform color separation and optical scanning can be obtained.

This allows color image input devices, color printers, etc. to easily and reliably perform color separation and light scanning without using mechanical shutters, color light sources and their switching devices, imagers with color filters, or light projection devices. This can be realized using the optical scanning device of the present invention that simultaneously performs the following. In particular, since it does not have the mechanical shutter, the scanning speed is high, and since it does not have three color light sources and their switching devices, it can be realized in a small size, light weight, and at low cost. Furthermore, when applied to a color image input device, since an imager with a color filter is not used, resolution can be increased, sensitivity variations between pixels can be reduced, and a color image input device can be obtained at low cost. can.

manuscript Optical system ...-CCD array

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing an embodiment of the present invention, in which (a) is a top view and (b) is a side view. FIG. 2 is a conceptual diagram showing another embodiment of the present invention, in which (a) is a top view and (b) is a side view. FIG. 3 is a diagram of conventional example [1], FIG. 4 is a diagram of conventional example [2], and FIG. 5 is a diagram of conventional example [3]. t -11------White light source 2---------1・-1--- Rotating polygon mirror with color filter (a) Top view (a) Top view Embodiment of the present invention Showing urine @ Figure 1 (b) side (support) A sign showing other embodiments of the present invention 2nd conventional example [1 Figure 3 Conventional example [2 Conventional example [3] 5th flash

Claims (1)

[Claims] An optical scanning device using a rotating polygon mirror, characterized in that an optical filter having wavelength selectivity is provided on each light beam reflecting surface of the rotating polygon mirror.