JPS5868363A - Reader - Google Patents

Abstract

PURPOSE:To obtain a small-sized reader by providing an optical means of transmitting a part of incident light and reflecting the remainder, in an image forming lens, and shortening optical path length. CONSTITUTION:At the internal center part of an image forming lens 31, a dichroic mirror 32 which transmits a part of incident light to the lens and reflects the remainder is provided. This mirror 32 reflects the 1st light having a long wavelength range including red light and transmits the 2nd light having a short wavelength range including blue light. For this purpose, the 1st light is photodetected by a photodetector 9 and the 2nd light is photodetected by a photodetector 10. Signals from those elements 9 and 10 are used for recording, thereby shortening the length of an optical path by use of a lens with short focal length.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reading device, and more particularly, to a reading device that illuminates a document and images the reflected light onto a light receiving element using an imaging lens to read image information on the document.

To read both images of a multicolor original, the original placed on the original table is irradiated with light from a light source such as a hapgen lamp to scan the entire area of the original, and the light reflected from the original passes through multiple reflective mirrors. The light enters a color separation means such as Dyke's or the like from an imaging lens, and the color separation means separates the light into light in a plurality of wavelength ranges and forms an image on a light receiving element such as a one-dimensional field image sensor. In such a reading device, the original is fixed and a light source and a reflecting mirror are moved to scan the entire area of the original, or the original is moved and scanned.

FIG. 7 shows an example of the configuration of such a conventional reading device, where l is a document table glass on which a document is placed, a bar-shaped light source such as a Hagen lamp or a fluorescent lamp, and Install it inside. the law of nature,! , 4 are 1st, 2nd and 2J reflections, and the first reflection radar scans (sub-scans) the document surface while moving in the true direction along a guide rail (not shown) together with the light source. I'll scold you! and #13 ramirar are integrated by a support (not shown), and move on the aforementioned guide rail in the same direction B as the 11th runner at a speed minus the moving speed of the 11th runner. Further, 7 is an imaging lens, and 1 is a color separation means such as a Dyke mirror. 5. Transmit light in the short wavelength range including blue light,
An image is formed on a -dimensional solid-state image sensor, for example, CClHo.

Note that 1° from the CCD 9 has a predetermined number of light receiving elements in the direction perpendicular to rirr, and each CCD? and 1o are for reading the same position on the document. In addition, 11 is the national polity that accommodates each of these members.

In such a reading device, a light source J, a first mifuji, a J-th mirror! and the positions af, C, and s of the 11th Raise are indicated by dotted lines in the figure, respectively! and ≦', but at this time, from the document table l to the page 1. ≦, the optical path length at the lens 7t is always kept constant. Therefore, if the signals from the light receiving elements of the CCDs 9 and 10 are read out in order during sub-scanning (main scanning), sequential signals obtained by tester scanning the original image can be obtained.

In addition, No. JWJ shows another example of this type of conventional reading device, and this example reads the image by moving the document.
Here, l is the document feed p-ra, and one document n is
The image of position P''C'I on the reading glass n is read. That is, the light from the light source 1 is reflected at the position P and is made to enter the imaging lens via the first J-ra B. Furthermore, the dike mirror 1 separates the light into red light and blue light, which are received by the light receiving elements x and B.

Note that X is a holding plate that allows jl[II to be well focused on the bin F.

However, there are problems with such conventional reading devices.
Since the imaging lens γ and the color separation means 1 are arranged separately, a lens with a long focal length is required, and there is a limit to the miniaturization of the device. If it is necessary to separate into three or more colors, there is a problem with miniaturization, and the device becomes large.

SUMMARY OF THE INVENTION An object of the present invention is to provide a reading device that is miniaturized in order to eliminate such conventional drawbacks.

Hereinafter, the present invention will be described in detail based on the drawings.

Note that the same parts as in FIGS. 1 and 2 are given the same reference numerals.

FIG. 1 shows an example of the reading device of the present invention, which corresponds to the conventional example shown in FIG. Here, 31 is an imaging lens, and an optical means, for example, a dichroic mirror n, for transmitting a part of light incident on the lens and reflecting a part thereof is provided inside the imaging lens. This dike mirror n reflects the first light in the long wavelength range including red light, and transmits the first light in the short wavelength range including blue light. Therefore, the first light is received by the light receiving element 10, and the second light is received by the light receiving element 10.

Using the signals from these elements 10, recording can be performed by a known technique. By integrating the dichroic mirror 32 into the imaging lens 31 in this manner, a lens with a short focal length can be used, thereby shortening the optical path length of the reading device.

Figure 1 shows another example of the present invention, and corresponds to the conventional example shown in Figure 2. Here, V is an imaging lens,
The half scolding as an optical means mentioned above inside its center.
Set ξ. Further, q allows only light in the long wavelength range including red light to pass through. The bypass filter, Keyaki, is a four-pass filter that only passes light in the short wavelength range, including blue light.

Therefore, of the reflected light from the original, only the first light is received by the light receiving element X, and only the third light is received by the light receiving element 2. The image signals taken out from each of these elements I and 29 are processed by a well-known signal processing circuit (not shown) to obtain desired image information, and based on this information, for example, an inkjet head is driven and recorded on recording paper. do. In this embodiment as well, the optical path length can be shortened.

In addition, the third illustration and the PV! The flat type Dike mirror shown in J can be easily constructed, and it is extremely easy to integrate the mirror with the imaging lens.

As described above, according to the present invention, it is possible to shorten the optical path length of a reading device that can read documents of two or more colors, contributing to miniaturization of the device.

[Brief explanation of drawings]

1 and 2 are block diagrams showing an example of a conventional reading device, *sg and FIG. 2 are block diagrams showing two examples of a reading device of the present invention, respectively. l...Original table glass, K, J'...Light source,!・
...Kasa, da, san'l j a
j', t l≦ζ...mirror, 7...imaging lens,
l...Dichroic mirror, 9, /σ...
Light receiving element, /l... National polity, 1... Roller,
〃...Original, B...Original table glass, 3...
Light source, B...mirror, M...imaging lens, 1...dichroic mirror, x, zy...light receiving element, 〃...holding plate, button...imaging lens, invasion... Half mirror, da 3.
Country...filter. Patent applicant: Canon Co., Ltd.

Claims (1)

[Scope of Claims] 1) A reading device that irradiates a document with light and images the reflected light on a light-receiving element for each of a number of colors through an imaging lens to read image information on the document, The imaging lens is characterized in that an optical means for transmitting part of the reflected light and reflecting part of the reflected light is provided integrally with the imaging lens. reading device. 2. The reading device according to claim 1, wherein the optical means is a ditaleic mirror. 8) The reading device according to claim 1, wherein the optical means is a half mirror.