JPS6180121A - Optical beam recorder - Google Patents

Abstract

PURPOSE:To reduce the size of a device without increasing a polygonal mirror face by making variable the diameter of the image-forming spot in a sub- scanning direction according to the size of an exposing region where the image is visualized. CONSTITUTION:The light from semiconductor lasers 21, 22 are made incident respectively via collimating lenses 23, 24, a half mirror 25 and a polygonal mirror 27 on a photosensitive body 30. The beam diameters d1S and d2S in the main scanning direction along the axial direction of the photosensitive body are equal and the beam diameters d1C and d2C in the sub-scanning direction along the rotating direction are different. The beam diameter in the sub-scanning direction can be changed without changing the beam diameter in the main scanning direction by changing the local length of the two cylinder lenses constituting the lens part 23. The diameter of the mirror 27 is affected by the beam diameter in the main scanning direction. The exposing region is changed without increasing the diameter of the mirror 27 by the above-mentioned constitution, by which the reduction in the size of the device is made possible.

Description

[Detailed Description of the Invention] [Field of use in sedentary work] This invention relates to a light beam recording device for recording images on a recording medium of 11 types. , More specifically, the light beam is sent to the information section,
The recording medium is exposed to light with a change, a,; The present invention relates to a light beam recording device.

[Conventional Technique 1iII] As shown in FIGS. 13 to 15, this conventional fJi device includes first and second semiconductor lasers (11, (
The light beams from 2) are each collimated by a lens (3).
, (4), the collimated light is irradiated onto a half mirror or polarizing beam splitter (5), and after (7), the high-speed 1
ffi! The light beam is irradiated onto a rotating polycon mirror (7), and the light beam deflected by the polycon mirror (7) is directed to the same position on the photoreceptor drum (10) via an imaging lens (81) and a mirror lens (9). A known method is known in which an imaging spot is obtained in the axial direction of the photoreceptor drum (11) in the axial direction of the photoreceptor drum and in the sub-scanning direction (12) in the rotational direction of the photoreceptor drum (101). There is a known system in which the beam diameter is changed in order to give gradation to the print density (Japanese Unexamined Patent Publication No. 57-1).
64759, JP-A-57-1713857) 1, in this case, the first and second semiconductor lasers (1
), (2) to O beam (151% (16) is the exit diameter (dl) from the collimating lens (3), (4), (
d2) is different, the imaging spot diameter (DI), (D2) on the photoreceptor drum aα is different as follows. In other words, they have the following relationship.

Here, f is the combined focal length of cylinder lenses +61, +91 and M' lens (8), and λ is the wavelength of light.

Therefore, a small spot diameter (D
To obtain +8 (D2), V has a large incident beam diameter (
dl) and (d2) are required. Specifically, as shown in FIGS. 16 and 17, for example, an imaging spot (area (St) of 13) by the first semiconductor laser (1) and an exposure spot by the 20th semiconductor laser (2) are formed. (If the ratio of the area (S2) of 141 is St: 5z = 1: 2 and the print density has gradation, the relationship between the beam diameter (Dυ and (D2) is D+: D2 = 1
: l'z Therefore, the beam diameter (dl) before entering the polygon mirror surface needs to be six times larger than (d2).

As stated above, in order to obtain a small spot diameter on a recording medium such as a photoreceptor drum, a large incident beam diameter is required. A polygon mirror requires a large mirror surface to emit light without vignetting. Therefore, the load on the motor for rotating the polygon mirror increases, making it difficult to rotate the polygon mirror at high speed, and causing light to travel at high speed.
The disadvantage was that it became impossible. In addition, if the polygon diameter is smaller than necessary to solve this problem, the heel-is vignetting will be scattered, which will cause the spot on the photosensitive material surface to become larger and flare to occur. There were some inconveniences such as:

[Means for solving problems]

The present invention has been made with the intention of solving the above-mentioned problems, and as a means to solve the above-mentioned technical problems, a light beam is modulated by an information signal and exposed onto a recording medium, and the light beam is In a light beam recording device that presses the LC spear area or the area that is not exposed by the light beam, the image formation on the recording medium is difficult due to the size of the exposed area to be imaged. The shape of the spot is only in the direction of the sub-runner.
The present invention aims to provide an optical beam recording device characterized by f.

[Effect]

The above technical T stage operates as follows.

In a light beam recording device, in order to increase speed, the gap between irradiating multiple light beams onto the same location on the recording body is fixed by selectively focusing 10,000 of the light beams. The diameter of the imaging spot in the direction is 1-I L I
l-111=b:,<-t;r,,:I/7N
By obtaining an exposure area such as Become,.

〔Example〕

Below-1, this redundant embodiment will be explained in detail based on the drawings.
jis, light''-ru.

Figure 1 shows the structure of the optical beam recording device of the present invention.
It's a simple thing.

The light beam recording device of the present invention is different from the conventional nine-beam recording device. - Similarly, the light beams from the first semiconductor laser 2]/and the second) 1' dedicated laser (2) are
( , :J remator lens 8 angle, collimator lens 1
The half mirror or polarized beam enters through the cylinder 9 and the light beam irradiated on the half mirror or polarized beam cylinder 4 is cylinder-shaped.
Of course, the polygon mirror illuminates through the lens helmet.
(Light beams 1 and 6 irradiated by Recon Mirror Co., Ltd.)
+'f46 〃It is composed of a focusing lens (c) for forming an exposure image on the bone rest tram field on the sea stock τ Afuno 1 and an image forming lens. The light beam V from the first and second semiconductor lasers eυ, of the light beam recording device of the present invention rotates the fixed plate 01) and the photoreceptor drum (g) along the axial direction of the photoreceptor drum 90. An imaging spot of the sub-travel beam 62 along the direction can be obtained. In this case, in the light beam device of the present invention, the first and second
The semiconductor laser Qυ, the collimating lens part from the iron,
The beam diameter (dls), (d2s) in the main kW direction after passing through the collimating lens (incorporated) is in the relationship of dls/d2s. The beam diameter (d+c) and (dzc) of Kagosuke Sosuke are ctlc>d2. have a relationship of Therefore, the above collimating lens part (
2) is composed of a combination lens group including a collimating lens 01) as shown in FIGS. 4 and 5, and a second cylinder lens (4). In this case, the lth 7 linter lens hs and the second
The focal length ratio f1:f2 of the linter lens i3 is
d1c'dl'c'' f2: fl,
The beam diameter in the sub-scanning direction can be changed without changing the beam diameter d1s in the main-scanning direction. In addition, dlc
is the beam diameter in the sub-scanning direction on the recording medium side of the cylinder lens O1 of 932, and d/c is the beam diameter in the sub-scanning direction on the semiconductor laser side of the first 7 Linder lens (I4).

On the other hand, the beam diameter (d+a), (dtaλ(dIc) and (dzc)) emitted from the above-mentioned collimator lens
), (DzB), (Drc), and 02c) have the following relationship. In other words, there is a relationship. Here, assuming that the ratio of the area S1 of the imaged spot by the first semiconductor laser e and the area S2 of the imaged spot by the second semiconductor laser (equipment) is Sl:82=L:2, Assuming that gradation is given to gradation, in the conventional optical beam recording device, as shown in Fig. 16 /ζ,
The relationship between the beam diameters (D, ) and (D2) is expressed as D, :D,=l
Since the area ratio was changed as 2 1m, the beam diameter (dυ) before entering the polygon mirror surface was five times larger than (d2), but in the light beam recording device g of this invention,
As shown in Fig. 3, the diameter of the incident beam on the polygon mirror surface is d+a = d2B in the main scanning direction, and d, c: 2 dzc.

Here, the diameter φ of the polygon mirror is determined by the following well-known formula based on the beam diameter in the main scanning direction. In other words, the relationship is as follows. Here, d is the incident heat on the polygon mirror ((η, n is the number of surfaces of the polygon mirror, and θ is the effective deflection angle of the beam.

Therefore, as the beam diameter in the main scanning direction increases, the polygon mirror diameter increases, making it difficult to rotate at high speed. However, in the optical heat recording device of the present invention, as described above, since als = (12 s), The diameter of the polycon mirror is determined by the diameter of either the first or second semiconductor laser ep1 (
Even if the exposure beam from 4) is selected, there will be no vignetting of the beam with the same diameter. However, (, μ゛1− of the first semiconductor laser ?υ and the second semiconductor laser II (4),
As shown in FIGS. 3 and 6, by selectively exposing the light by a switching means (not shown), the first and second
Different light distributions on the surface of the photoreceptor drum are obtained from the semiconductor lasers eυ and 2, and by selectively exposing them, it is possible to impart gradation to the degree C.

In the above-described large-scale embodiment, the means for enlarging the diameter of the beam incident on the polygon mirror gradient only in the sub-scanning direction is the collimating lens 0η and the first and twentieth linter lenses 5+.
Although a case has been described in which the collimating lens part is formed by the combination lens of 3.143, it is not necessarily limited to the above combination lens. For example, as shown in FIGS. 7 and 8, the collimating lens part 0 (L, concave and convex cylinder lenses, (C) and +4 can be formed, and as shown in Figures 9 and 10, it is composed of a collimating lens 01) and a triangular prism (G). You can also. Furthermore, as shown in FIG. 1118I and FIG. (diameter in the sub-scanning direction of the beam incident on the polygon mirror): (diameter in the sub-scanning direction of the beam incident on the polygon mirror) By using a semiconductor laser I4' having the following characteristics, it is possible to expand the incident beam diameter in the i-direction. can.

The light beam recording device of the present invention is a light beam recording device that modulates a light beam with an information signal, exposes the recording medium, and visualizes the area exposed by the light beam. It can also be used in conjunction with a light beam recording device that visualizes areas not exposed by the beam.

〔Effect of the invention〕

As described above, according to the light beam recording device of the present invention, the shape of the imaging spot on the recording medium is scanned in the sub-scanning mode according to the size of the exposed area visualized by the light beam. Since only the direction is variable and the η of the imaging spot in the main scanning direction is the same, it is possible to change the print density by changing the exposure area on the recording medium without increasing the diameter of the polygon mirror. Since it is possible to provide an optical beam recording device which can produce a high-speed light quantity and is capable of producing a high-speed light beam, its utility value is remarkable.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view of a light beam recording device of the present invention, FIG. 2 is a schematic side view thereof, and FIG.
Figure 4 shows the imaged spot obtained by the light beam recording device of the present invention, its light intensity distribution in the main scanning direction and the sub-scanning direction, and a first embodiment of the collimating lens section in the present invention. A schematic side view, FIG. 5 is a schematic plan view thereof, FIG. 6 is an explanatory diagram showing imaging spots of a plurality of light beams, and FIG. 7 is a schematic side view showing a second embodiment of the collimating lens section in this invention. , FIG. 8 is a schematic plan view thereof, FIG. 9 is a schematic side view showing a third embodiment of the collimating lens section in the present invention, FIG. 10 is a schematic plan view thereof, and FIG. 1. A schematic side view showing another embodiment for enlarging the diameter, FIG. 12 is a schematic plan view thereof, FIG. 13 is a schematic perspective view showing the structure of a conventional optical beam recording device, and FIGS. 14 and 15. are a schematic plan view and a schematic side view thereof, respectively, and FIG. , FIG. 17 is an explanatory diagram showing the imaging spots of a plurality of light beams in a conventional light beam recording device. (Explanation of No. 4.1) N...First semiconductor laser @... ...Second semiconductor laser (4)...Collimating lens part a9...
・Collimating lens (A)・・・Half mirror or polarized beam blurring lens (C)・・・Polycon mirror ■・・・Imaging lens (c).../Linter lens......Photosensitive drum (recording medium) 0υ...
...Main scanning direction 02... Sub-scanning direction (!
υ・・・Colinaught Lens (1)...First Nlinder Lens (li...
...Second/Linda lens i-9...Concave lens O→...Convex/Linda lens 0~...Triangular prism ri η...・・・・・・
Semiconductor Laser 1'1j Applicant Fuji Xerox Co., Ltd. Agent Tomohiro Naka, Patent Attorney Katsuo Naruse Figure 3 (Q) (b) Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 F1 Figure 13 p Figure 14

Claims (2)

[Claims] (1) In a light beam recording device that modulates a light beam with an information signal and exposes the recording medium, and visualizes the area exposed with the light beam or the area not exposed with the light beam, A light beam recording apparatus characterized in that the shape of the imaged spot on the recording medium is variable only in the sub-scanning direction depending on the size of the exposed area. (2) When irradiating a plurality of light beams to the same position on a recording medium, one of the light beams is selectively focused to make the diameter of the imaged spot in the main scanning direction the same;
2. The light beam recording apparatus according to claim 1, wherein an exposure area is obtained in which the diameter of the imaging spot in the sub-scanning direction is different.