JPS60201319A - Optical device - Google Patents

Abstract

PURPOSE:To scan plural laser beams excellently by one scanner without increasing the size of the scanner by allowing at least one of plural laser light sources to oscillate a laser beam with different wavelength. CONSTITUTION:The 3rd laser beam of 790nm is scanned on the surface of a photoconductor 12 to form an electrostatic latent image, which is supplied with toner of the 2nd color from the 2nd developing device 16 and developed. Then, the photoconductor 12 is charged electrostatically by the 2nd corona charger 17 similarly to the 2nd corona charger 15 and irradiated with the 2nd laser beam of 820nm to form an electrostatic latent image. This electrostatic latent image is supplied with toner of the 3rd color from the 3rd developing device 18 and developed. Further, recording paper P is sent out of a supply cassette 22, sheet by sheet, by a feed roller 23, and timed by an aligning roller 34 and sent to a transfer device 19, and a tri-colored toner image on the photoconductor 12 is transferred to the recording paper P by the corona discharging of the transfer device 19.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an optical device included in, for example, an electrophotographic color radar beam printer.

[Technical background of the invention and its problems]

It is known that this type of optical device is equipped with a plurality of Rade light sources, each of which oscillates a Rade beam, which is deflected and scanned by - number of scanners to irradiate it onto a photoreceptor to print in multiple colors. ing.

As a method of deflecting and scanning the plurality of laser beams with one scanner, for example, as shown in FIG.
The method used was to make the light incident at an angle to the optical axis of the fθ lens 1, or to make the light incident parallel to the optical axis of the fθ lens 1, but at a distance from the optical axis, as shown in Figure 2. .

However, in the method shown in FIG.
As the scanner 2 rotates, the reflection position on the reflection surface moves in the Y-Y direction, which deteriorates the scanning linearity on the photoreceptor 3. There was a problem.

Furthermore, although the method shown in Fig. 2 is practical for up to two beams, for three or more beams, the distance between each beam is kept at least equal to the beam diameter, so the thickness of the scanner 2 only becomes thicker. However, there is a problem that the aperture of the fθ lens 1 is large, making it impractical.

Further, in order to solve the above-mentioned problem, a method of using two or more scanners may be considered, but in this case, there is a problem that the entire device becomes large and expensive.

Incidentally, the electrostatic latent image formed on the photoreceptor 3 formed by the irradiation with the Ledeh beam is developed by a developing device that supplies developing agents of different colors 4, s, and eh in FIGS. 1 and 2, respectively. It is supposed to be done.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide an optical device that can efficiently scan multiple laser beams with a single scanner without increasing the size of the scanner. This is what we are trying to provide.

[Summary of the invention]

SUMMARY OF THE INVENTION In order to achieve the above object, at least one of the plurality of laser light sources oscillates a laser beam of a different wavelength from that of the other laser light sources.

[Embodiments of the invention]

The present invention will be described below with reference to an embodiment shown in FIGS. 3 to 7. In the figure, 11 is the main body of the Glinter, and this main body 1
A drum-shaped photoconductor 12 whose surface is made of amorphous selenium or the like is rotatably provided at the center of the photoconductor 1 . A first corona charger 13, a first developer 14, a second corona charger 15, a second developer 16, and a third corona charger are arranged around the photoconductor 12 in order along the rotation direction thereof. corona charger 17, third developing device 18, :Fa static eliminator 18a1 transfer device 19, corona static eliminator 20, and cleaning device 21
is installed.

Further, a paper feed cassette 22 is provided on one side of the main body 11, and the paper P in the paper feed cassette 22 is fed to the paper feed row 2.
Each rotation of 23 feeds one sheet at a time. This paper P is sent between the photoconductor 12 and the transfer device 19 via an aligning q-ra 24. Further, 26 is a conveying means, and this conveying means 25 conveys the paper P on which the image has been transferred and sends it to the fixing device 26. After passing through the fixing device 26, the paper P is discharged to a paper discharge tray 28 via a paper discharge roller 27.

On the other hand, an optical device 2 is provided on the other side of the printer main body 1.
9 is provided. As shown in FIG. 4, this optical device 29 is equipped with a Rade light source section 30. This radar light source section 30 includes first to third semiconductor radars 31, 32.3.
3, these first to third semiconductor radars 31
°sat and ss are modulated by the driver 34 shown in Figure #I3 according to the print information. The emission wavelength of the first and third semiconductor radars 31°33 is 7
90 nm, and the emission wavelength of the second semiconductor radar 32 is 8
20 nm.

Further, the first and second semiconductor radars 31 and 32 are installed in the same plane in the Y-Y direction at right angles to each other.

Further, the beam from the third semiconductor laser '41 is collimated into a parallel beam of a predetermined diameter by a collimating lens 35e, and is converted into a beam C by an I-repun mirror serving as a scanner.
Reach 36. Further, the beam from the second semiconductor laser 32 is collimated by a collimating lens 35b,
The beam is bent at a right angle by the prism 38b and reaches the polygon mirror 36 as a beam b.

Furthermore, the beam from the first semiconductor laser 31 is emitted downward, and is separated by a distance d2 from the optical axis XX of the υfθ lens 39 to the collimator lens 35a and the prism 38m.
The beam leaves and reaches the polygon mirror 36 as a beam. The above beam a.

When viewed from the direction AA shown in FIG. 4, beams b and c are scanned in an overlapping state as shown in FIG. 6. In addition, the beams a, b, and c are fθV lenses 3
9, the difference due to the characteristics of the fθ lens 39 can be ignored. The distance d between the beam b and the beams tr and c only causes a time difference in adjusting the distance, and does not cause a difference in scanning distortion. Also, the ray f k! deflected by the polygon mirror 36 and the fθ lens 39 ! ”-A @, b.

All of the laser beams C are deflected by a right angle prism 40 and a plane mirror 41 to scan and expose the photoconductor 12.

Further, the laser beams b and c are deflected downward by the right angle prism 40 and then reach the dichroic mirror 4-2.

This dichroic mirror 42 has the characteristics shown in FIG.
The laser beam C with a wavelength of 820 nm is reflected and reaches the plane mirror 43, and is emitted from the second semiconductor laser 32 with a wavelength of 820 nm.
The beam b of nm is transmitted and reaches the plane mirror 44.

Therefore, when printing, the first to
first to third radar beams a modulated from the third semiconductor radar 31, 32, 33 according to the printed information, respectively;
b, e are oscillated, and these first to third laser beams a
, b, and e are sent to a polygon mirror 36 via collimator lenses 35h, 35b, and 35c and prisms 38m and 38b, respectively, and are scanned by the rotation of this polygon mirror 36. The first to third scanned
Ledebeam a, b.

C is sent to the right angle prism 4oK via the fθ lens 39, the first Rade beam a is sent to the upper plane Mi 2-41, and the second and third Rade beams b and c are sent to the lower dichroic, Kumi 2-42. sent to. The second laser beam b passes through the dichroic mirror 42 and is sent to the plane mirror 44, and the third laser beam C is deflected in the right angle direction by the dichroic mirror 42 and sent to the plane mirror 2-43.
sent to.

The first laser beam a mentioned above is reflected by a plane mirror 41 and irradiated onto the first irradiation part of the photoconductor 12, and the second laser beam b is reflected by a plane mirror 44 and irradiated onto the first irradiation part of the photoconductor 12.
The third radar beam C is reflected by the plane Mi 2-43 and is irradiated onto the third irradiation part of the photoconductor 12.

On the other hand, the photoconductor 12 is driven to rotate, and its surface is uniformly charged by the first corona charger 13, and the charged surface is irradiated with the first radar beam a, thereby causing a shock. , an electrostatic latent image is formed. This electrostatic latent image is developed by supplying the first color toner from the first developing device 14. Next, the photoconductor 12 is charged by the second corona charger 16, and the portion where the potential is darkly attenuated and the portion where the potential is attenuated by exposure to the first laser beam a are restored to the initial potential. The surface of this photoconductor 12 has a third
The radar beam C is scanned to form an electrostatic latent image. This electrostatic latent image is developed by supplying the second color toner from the second developing device 16. Next, the photoconductor 12 is transferred to the second corona charger 1 described above by the third corona charger 17.
5, and is irradiated with the second radar beam b to form an electrostatic latent image. This electrostatic latent image is developed by supplying the third color toner from the third developing device 18. Thereafter, the photoconductor 12 is removed with a static eliminator 1ath to eliminate the residual potential on the surface and the developed 3
The potential of the color toner is controlled and rotated to the transfer device 19.

On the other hand, at this time, the recording paper P is fed one by one from the paper feed cassette 22 to the feed roller 23, and then, after being timed by the aligning roller 34, the recording paper P is sent to the transfer device 19.
The three-color toner image on the photoconductor 12 is transferred to the recording paper P by the corona discharge of the transfer device 19. The recording paper P onto which the three-color toner image has been transferred is peeled off from the photoconductor 12, and the toner image is fixed in a fixing device 26. After the residual surface potential of the photoconductor 12 after transfer is removed by a whirling corona static eliminator 20, the photoconductor 12 is cleaned by a cleaning device 21 in preparation for the next printing process.

Although three laser beams are used in the above embodiment, the present invention is not limited to this, and four or more laser beams may be used.

In addition, for the Rade light source section 30, three separate semiconductor Rades: il, 32.33 were used, but the invention is not limited to this, and those having an integral structure formed into an array, especially those having the same emission wavelength, may be formed into an array. Of course, it is also possible to use a combination of other solids, gases, etc., and the emission wavelength can be selected depending on the characteristics of the photoconductor drum and the dichroic and cumolar characteristics.

Further, as shown in FIGS. 9 and 10, first to third semiconductor radars 51, 52, and 53 are arranged, and these first to third semiconductor radars 51, 52, and
First and second dichroic and mirror 54.55 are arranged in the optical path of the third semiconductor laser 61. The light beam may be incident on the polygon mirror 36 as a single beam bundle for scanning.

The first to third semiconductor radars 51, 52, and 53 are fθ
They are arranged at right angles to each other on the same plane including the optical axis XX of the lens 39, and the first semiconductor radar 51 has an optical axis of 820 nm.
The second semiconductor radar 62 and the third semiconductor radar 53 are configured to oscillate a Rade beam having a wavelength of 790 nm and 770 nm, respectively.

Further, the first and second dichroic mirrors 54
．． 55 has the characteristics as shown in FIG. Cumira 55 is 790 nm
It has a characteristic that beams with wavelengths above 770 nm are transmitted, but beams with wavelengths below 770 nm are reflected.

In addition, 515, 57, 58 in the figure are collimating lenses,
These collimate the radar beams a, b, and c emitted from the first to third semiconductor radars 51, 52, and 53 into a parallel light source with a predetermined diameter.

As a result, 8 emitted from the first semiconductor laser 51
20 nm laser beam aid collimator lens 66
The beam is made into parallel light by the beam a' and reaches the dichroic mirror 42, but since the wavelength is 820 nm, it is transmitted through the first and second dichroic mirrors 54 and 55 and is incident on the polygon mirror 36. Further, the 790 nm light emitted from the second semiconductor laser 52 is collimated by the collimator lens 57 and reflected by the first dichroic mirror 54 as a beam b', and the beam from the first semiconductor laser 51 is The beam passes through the second dichroic mirror 55 with its optical axis substantially aligned with i and enters the mirror 36. Furthermore, the 770 nm light emitted from the third semiconductor laser 53 is transmitted through the collimator lens 6.
8, it becomes a parallel beam and is reflected by the second dichroic mirror 55 as a beam C', and the optical axes of the Rede beams a and b coincide with #1? The light is incident on the ribbon mirror 36. As a result, three radar beams, 1. b#, CF, are the optical axes almost aligned? incident on the ribbon mirror 36,
The light is deflected by the rotation of the polygon mirror 36, and then focused by the fθ lens 39 so as to scan the photoconductor 12 in a straight line. The three radar beams a', b', and e' corrected and focused by the fθ lens 39 are then sent to a third dichroic mirror 59 having the same characteristics as the second dichroic mirror 55, as shown in FIG. reach Since this third dichroic mirror 259 reflects wavelengths of 770 nm or less, the third laser beam C' is reflected upward, and then reflected again by the mirror 60 to scan and expose the photoconductor 12. do.

Further, the Lede beams, l and bl, transmitted through the third dichroi, the cummirror 59, are reflected downward by the mirror 61, and the fourth dichroi has the same characteristics as the first dichroi, the cumirra 54.

Reach Cumilla 62. This fourth dichroic mirror 62 transmits light of 820 nm or more, so the Radhe beam a' is transmitted and reflected by the mirror 63 to the photoconductor 1.
2. Scan and expose the top. Further, the laser beam b' reflected by the fourth dichroic mirror 62 is reflected by the mirror 64 and scans and exposes the photoconductor 12.

According to this embodiment, there are three radar beams a.

Since the beams b and c can be made into a single beam bundle and incident on the polygon mirror 36, there is an advantage that the thickness of the polygon mirror 36 can be further reduced.

〔Effect of the invention〕

As explained above, in the present invention, at least one of the plurality of laser light sources oscillates a Rade beam with a wavelength different from that of the other Rade light sources, so unlike the conventional method, the intervals between the plurality of Rade beams are widened. It can be scanned with excellent linearity without any distortion. Therefore, there is no need to increase the thickness of the scanner, and the scanner can be made more compact.

[Brief explanation of the drawing]

Fig. 1 is a schematic block diagram showing a first conventional example, Fig. 2 is a schematic block diagram showing a second conventional example, and Figs. 3 to 7 show an embodiment of the present invention. Fig. 3 is a schematic configuration diagram showing the radar printer device, Fig. 4 is a plan view showing the optical system, Fig. 5 is a side view thereof, Fig. 6 is an arrangement diagram of multiple radar beams, and Fig. 7 is a diagram showing the arrangement of multiple radar beams. Graphs showing the characteristics of dichroic and cummirrors, and FIGS. 8 to 11 show other embodiments of the present invention. FIG. 8 is a schematic configuration diagram showing a radar printer device, and FIG. 9 is an optical FIG. 10 is a plan view showing the device, FIG. 10 is a side view thereof, and FIG. 11 is a graph showing the characteristics of the dichroic mirror. 31.32.3B, 61, 52.53... Rade light source, a, b, c, a', b', c'...-Laser beam, 36... Scanner. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figures 5-6 Figure 7 Layer length Figure 9 Figure 10 Figure 11 Figure 91 Moxibustion Elhi,

Claims (6)

[Claims] (1) In a device in which a plurality of laser light sources respectively oscillate Rade beams and these are scanned by - number of scanners to respectively irradiate a plurality of locations on an irradiated object, at least one of the plurality of Rade light sources is An optical device characterized by oscillating a laser beam of a wavelength different from that of a Rade light source. (2) The optical device according to claim 1, characterized in that at least two radar beams having different wavelengths are scanned within the same plane. (3) Claim 1 or 2 characterized in that a medium is provided in the scanning optical path of at least two Rade beams having different wavelengths to reflect one Rade beam and transmit the other laser beam. optical device. (4) The optical device according to claim 1, 2'' or 3, characterized in that a plurality of laser beams are incident on the scanner at a distance of at least a radius of the scanner. (5) Any one of claims 1 to 4, characterized in that a plurality of Radhe beams are superimposed using a dichroic or a chromium mirror, and are incident on a scanner as a single beam bundle to be scanned. optical device. (6) The optical device according to claim 5, characterized in that a plurality of radar beams scanned by a scanner are separated by a dichroic or a cummirror.