JPS5876858A - Original reader - Google Patents

Abstract

PURPOSE:To manufacture a reader easily at low cost, by using a readout box where the 1st and 2nd light transmission parts are formed. CONSTITUTION:Laser light is guided to a readout box 30 through a polygon mirror 23, lens 24, dichroic mirror 25, and mirror groups 25-29 to illuminate an original on a platen 32 through the 1st and 2nd light transmission parts 30a and 30b by a cylindrical lens 31. Reflected light from the original surface is reflected by a convergence surface 30c to illuminate a photoelectric converting element 34, thus reading information. This readout box 30 moves on a guide ratil, etc., to left and right with the same peripheral speed of a photosensitive drum 50. A hard copy is obtained by allowing light reflected by a mirror 35 to illuminate the photosensitive drum 50 through a cylindrical lens 36.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a document reading device that scans a document surface with a laser beam and reads a document image based on changes in the amount of reflected light on the document surface.

Conventional document reading devices guide a laser beam emitted from an Hθ-Ne gas laser or the like to the document surface through an optical system including a beam expander, polygons, etc., and receive the reflected light from the document surface. The end face (the end face facing the document surface) is received by a group of glass fibers arranged in a straight line, and the other end face of this glass fiber group is bundled and the light emitted from there is applied to a bottom multiplier to transmit image information. It was something to be gained. In conventional devices that use a group of glass fibers, it is necessary to align the light-receiving end faces of the glass fibers and arrange them in a straight line in the main scanning direction. However, since the glass fiber itself is expensive, there is a problem in that the cost is high.

The present invention has been made in view of the above-mentioned problems, and includes disposing a reading box having first and second light transmitting parts near the document setting position, and directing the laser beam to the first and second light transmitting parts. guiding the light reflected from the document surface to the document surface through the second light transmitting section, and guiding the reflected light from the document surface into the reading box through the second light transmitting section, and condensing the light by the light condensing surface of the reading box; By detecting with a photoelectric conversion element provided in the reading box, an easy-to-manufacture and low-cost document reading device is realized.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIGS. 1 and 2 are explanatory diagrams showing one embodiment of a document reading device according to the present invention, and show a case where the document reading device is embodied as a laser printer. Of the two figures, Figure 1 is a configuration diagram seen from the top side, and Figure 2 is a configuration diagram seen from the front side (for ease of understanding, some parts are shown only in one drawing). Ta). In the figure, 1 is a reading laser, for example, the wavelength is 6.
It is an 11e-Ne laser that outputs 328 laser beams. The laser beam output from the reading laser 1 is transmitted to the mirror 2. Shutter 3. Mirror 4. The configuration is such that the light passes through the cylindrical lens 5 and the beam expander 6 and enters the front side of the single dichroic mirror 7. 8 is a recording laser whose output light wavelength is determined in relation to the spectral sensitivity of the photoreceptor forming the surface of the photoreceptor drum. In this example, a short wavelength (for example, 4416
A He-Cd laser is used. A beam shifter 9 is arranged in the beam optical path of the recording laser 8 to adjust the optical path in parallel, and the laser beam after passing through the beam shifter 9 is reflected by a mirror 10 and then enters a beam light amount stabilizing device 11. It has become. This stabilizing device/device 11 stabilizes the power of the laser beam directed to the subsequent optical system. The laser beam after passing through the stabilizing device 11 is condensed by a lens 14, passes through a shutter 15, and enters an acousto-optic modulator 16, where the laser beam modulated is transmitted through a slit 17. Only the primary light is extracted, and after being collimated again by the lens 18, the mirror 19. Cylindrical lens 20° beam expander 21 and mirror 22
The light is made to enter the rear surface side of the dichroic mirror 7 via.

The dichroic mirror 7 has the property of transmitting only light of a predetermined wavelength and reflecting the others; in this embodiment, the laser beam from the reading laser 1 is reflected (red light is reflected),
Laser beam for recording laser 8? The laser beams from both lasers 1 and 8 are combined and made incident on the reflective surface of the polygon 23. This polygon 23 is rotating at a constant speed, and the laser beam deflected by its reflecting surface passes through an f/θ lens 24 and enters a dichroic mirror 25. Like the dichroic mirror 7 described above, the dichroic mirror 25 has the characteristics of transmitting blue light and reflecting red light, so that the combined beam is again separated into a recording laser beam and a reading laser beam. . The reading laser beam separated by the dichroic mirror 25 is guided to the reading box 30 by reflection mirrors consisting of reflection mirrors 26, 27, 28 and 29.

The reading box 30 includes first and second light transmitting sections 30a, as shown in FIGS. 3 and 4.

30b is formed. The first light transmitting section 30a guides the reflected light from the mirror 29 into the reading box 30.
A cylindrical lens 31 is fixed there.

Further, the second light transmitting section 30b includes a cylindrical lens 3.
The laser beam that has passed through the scanner 1 is irradiated onto an original platen 32 made of a transparent glass plate, and the reflected light from the original surface is guided into the reading box 30 again. Inside the reading box 30, a photoelectric conversion element 34 is provided for detecting the light guided into the reading box 30 by the second light transmitting section 30b and reflected by the light collecting surface 30c. As this photoelectric conversion element 34-, a photomultiplier or a semiconductor photosensor is used. Although not shown, the reading box 30 is supported by a guide rail or the like so that it can move in the left-right direction in FIG. They are driven by a motor or the like at the same speed. At this time, the 28.29 mirror group needs to move at half the speed of the reading box 30.

On the other hand, the recording laser beam separated by the dichroic mirror 25 is reflected by the mirror 35, passes through the cylindrical lens 36 and the protective glass plate 37, and is irradiated onto the photoconductor on the surface of the photoconductor drum 50, thereby forming a laser beam on the surface of the photoconductor. The electrostatic latent image produced is made into a hard copy using a known electrophotographic process 2 (with respect to each device that performs the electrophotographic process, only the developing device 51 is shown in FIG. 2, and the others are omitted).

Next, a document reading operation in the above embodiment apparatus will be explained. Reading in this apparatus is performed by moving the reading laser beam in the main scanning direction using the polygon 23, and moving the reading laser beam in the sub-scanning direction by moving the reading box 30 at the same speed as the circumferential speed of the photoreceptor as shown in FIG. towards the left or right)
This is done by moving to . During this scanning, the reflected light from the document surface is generally scattered, and is transmitted to the second light transmitting section 3.
0b, the light is guided into the reading box 3O, reflected by the light collecting surface 30C of the reading box 30, and illuminates the photoelectric conversion element 34. Therefore, when a reading laser beam scans a document having a pattern as shown in FIG. 4(a) in the direction of the arrow in the figure, a signal as shown in FIG. 4(b) is output from the photoelectric conversion element 34. In this specific example, as shown in FIG. 5, the output signal of the photoelectric conversion element 34 is amplified by the first amplifier 70 and converted into a binary signal by the binarization circuit 71 (see FIG.
(c)) is applied to the second amplifier 72, and the output signal of the second amplifier 72 drives the acousto-optic modulator 16 to modulate the laser beam and control the laser beam irradiation onto the photoreceptor. and have obtained a hard copy.

Note that the document reading device described above can be used not only for laser printers, but also for laser printers that also have the function of electrically receiving image information from a computer or the like to obtain a hard copy. Further, although the case of reading with a laser beam of a gas laser has been shown, the same applies to a semiconductor laser. Furthermore, the optical system does not need to be limited to that of this embodiment.

Further, although the embodiment has been shown in which the original platen 32 is fixed and the reading box 30 is moved, the reverse may be used.

As explained above, the present invention has a major feature in that a reading box in which first and second light transmitting parts are formed is used instead of a light pipe made of a group of glass fibers. Compared to optical conduits made of glass fibers, which are troublesome and expensive to manufacture, this reading box is simply a box, and its light-transmitting part can also be constructed with slits, so it is easy and low-cost to manufacture. be. Therefore, according to the present invention, it is possible to obtain a document reading device that is easy to manufacture and at low cost.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are explanatory diagrams of one embodiment of the present invention.
The figure shows the structure as seen from the top side, and FIG. 2 shows the structure as seen from the front side. 3 is a perspective view of the reading box in FIG. 2, and FIGS. 4 and 5 are explanatory diagrams of the operation of the above embodiment. 1...Reading laser 5.20.31.36 Cylindrical lens 6.2
1... Beam expander 7.25... Dichroic mirror 8... Recording laser 23... Polygon 25...
・F・θ lens 3o...reading box 30a...
-First light transmitting section 30b...Second light transmitting section 32...Original table 34...Photoelectric conversion element 5
0... Photosensitive drum patent applicant Roku Konishi Photo Industry Co., Ltd. Representative Patent attorney Fuji Osamu Ijima Figure 2, Figure 3, Figure 4 (c) - Ryoichi "

Claims (1)

[Claims] In a document reading device that scans a document surface with a laser beam and reads a document image from changes in the amount of reflected light on the document surface,
A reading box having first and second light transmitting parts is arranged near the document setting position, and the laser beam is guided to the document surface through the first and second light transmitting parts, and the reading box is arranged near the document setting position. The reflected light is guided into the reading box through the second light transmitting part, is reflected and focused by a light collecting surface of the reading box, and is detected by a charging conversion element provided in the reading box. A document reading device characterized by: