JPS62296175A - Recording device - Google Patents

Abstract

PURPOSE:To easily reproduce a half tone and give an optional power distribution to a field angle, by causing laser rays of light to form an image on the surface of a photosensitive body in Gaussian distribution and projecting the rays of light of a 2nd light source on the same place after the rays of light are shaped to a fixed light pattern with a filter. CONSTITUTION:Laser light 2 is deflected with a rotating polygon mirror 6 and caused to form an image on a photosensitive body 11 by means of a lens system 8 in a Gaussian distribution. On the other hand, the rays of light of an LED array 9 which is a 2nd light source are projected on the same place on the photosensitive body 11 after optical energy is shaped to a fixed pattern. By superposing the two rays of light upon another after shifting the position of one rays of light by 180 deg., the energy distribution on the photosensitive body 11 is made uniform and the phase is made the same, so as to make a dot picture and half tone easily obtainable. Moreover, variation of picture density caused by the image angle is reduced and a dot picture can be obtained by modulating the power supply to the LED array 9.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention Field of Industrial Application The present invention relates to a recording apparatus such as a copying machine or a printer using an electrophotographic method.

2. Description of the Related Art In recent years, optical printers such as copying machines and laser printers that use electrophotography have become widespread due to the expansion of office automation.

An example of a conventional recording device will be described below with reference to the drawings. FIGS. 7 and 8 show a conventional recording apparatus. In FIG. 7, 71 is a semiconductor laser;
2 is a laser beam, 73 is a control circuit, 74 is a collimator lens, 75 is a converging lens system, 76 is a rotating polygon mirror, 77
is a motor, and 78 is a second converging lens system. Also,
In FIG. 8, 81 is a photoreceptor, 82 is a charger, 83 is a laser exposure device, 84 is a developing device, 85 is a transfer device, 86 is a photoreceptor cleaning device, and 87 is a static eliminator.

The operation of the recording apparatus configured as described above will be explained below.

First, a laser beam 72 from a semiconductor laser 71 is power modulated or ON-OFF controlled by a control circuit 73 according to an image signal, and then emitted and converted into parallel light by a collimator lens 74 .

The light is then focused by a converging lens system 75 toward a rotating polygon mirror 76 which is a laser deflector. The laser beam 2 reaching the rotating polygon mirror 76 which is rotated at a constant rate with high precision by the motor 77 is deflected by the rotating polygon mirror 76 . The laser beam emitted at a certain angle is then imaged by the second converging lens system 78 into a spot diameter having a Gaussian distribution of a certain size in the main scanning direction and the sub-scanning direction. With the above configuration, the laser beam 71
is focused and incident on the photoreceptor 81. Here, the developing process will be briefly explained. The photoreceptor 81 rotates in the direction of the arrow and is rotated by a charger 82 controlled by a charge control circuit.
charges are applied to the surface, and the aforementioned laser exposure device 83 forms an electrostatic latent image corresponding to the laser exposure pattern. The electrostatic latent image becomes a toner image by a developing device 84, and is transferred to a transfer paper by a transfer device 85. After the untransferred toner is scraped off by the photoconductor cleaning device 86, the charge on the surface is made uniform by the static eliminator 87. As a result of the above, the semiconductor laser 71
The more emitted laser 72 is visualized.

Problems to be Solved by the Invention However, with the above configuration, the final spot shape has a Gaussian distribution and only a certain visible image can be obtained, making it difficult to produce solid black. Also, halftone dots cannot be obtained, making it difficult to reproduce halftones. Furthermore, there was a problem in that the power was different depending on the angle of view.

In view of the above-mentioned problems, the present invention makes the spot shape not only in Gaussian distribution but also in an arbitrary shape, thereby making it easier to obtain halftone images and reproducing halftones and the like. Further, the present invention provides a recording device that can give an arbitrary power distribution to the angle of view.

Means for Solving the Problems In order to solve the above problems, the recording device of the present invention has a laser as a first light source, a second light source, and a second light source in front of the second light source. A filter is provided that shapes the light energy emitted from the light source into a certain pattern of light energy, and the light pattern formed by the first light source and the second light source is applied to the electrophotographic photoreceptor that forms the corresponding image. It has a configuration that irradiates the same area.

According to the present invention, with the above-described configuration, the filter transmittance is low in the Gaussian distribution where the power is high, and the transmittance is high in the low power positions, thereby making it possible to obtain a spot with uniform power. In addition, by reversing the dot image, halftone images become easier to reproduce, such as intermediate tones. Further, by setting the transmittance to be low in the portion facing the center of the photoreceptor and high in the portion facing the edge, changes in image density due to angle of view can be reduced.

Embodiment Hereinafter, a recording apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a recording apparatus according to a first embodiment of the present invention. In Fig. 1, 1 is a semiconductor laser, 2 is a laser beam, 3 is a control circuit, 4 is a collimator lens, 5 is a convergent lens system, 6 is a rotating polygon mirror, 7 is a motor, and 8 is a second convergent lens system. , 9 is an LED array, 10 is a filter, and 1) is a photoreceptor. FIG. 2 is a partially detailed view of FIG. 1.

The operation of the recording apparatus configured as described above will be explained below.

First, the laser beam 2 from the semiconductor laser 1 is power-modulated or 0N-
After being turned off, the light is emitted and converted into parallel light by the collimator lens 4.

The light is then focused by a converging lens system 5 toward a rotating polygon mirror 6, which is a laser deflector. The laser beam 2 reaching the rotating polygon mirror 6 which is being rotated with high precision and constant by the motor 7 is deflected by the rotating polygon mirror 6. The laser beam emitted at a certain angle is then imaged by the second converging lens system 8 into a spot diameter having a Gaussian distribution of a certain size in the main scanning direction and the sub-scanning direction.

The light emitted from the LED array 9, which is the second light source, is divided into arbitrary power by a filter 10, which is located in front of the second light source and shapes the light energy emitted from the light source into a certain pattern of light energy. I can give you cloth. Then, by irradiating the light pattern formed by the semiconductor laser 1 and the LED array 9 onto the same spot on the electrophotographic photoreflector 1) that forms the corresponding image, the curved throat shape can be changed to not only a Gaussian distribution but also a Gaussian distribution. , it can be made into any shape, and any power distribution can be given to the angle of view.

Note that the light emitted from the semiconductor laser 1 and the LED array 9 is prevented from entering the photoreceptor through other routes.

As described above, according to this embodiment, by providing a filter that shapes the light energy into a certain pattern of light energy in front of the LED array, the individual light patterns of the semiconductor laser and the LED array can be adjusted according to the filter. For example, in FIG. 3, tal is the light energy distribution on the photoreceptor surface by the semiconductor laser + b) is the light energy distribution on the photoreceptor surface by the LED array. The energy distribution fc) is the light energy distribution on the surface of the photoreceptor superimposed by the semiconductor laser and the LED array.

In this way, if the light energy distribution on the photoreceptor surface by a semiconductor laser shows a Gaussian distribution shape, the transmittance of the filter is low in areas where the power is high, and the transmittance is high in areas where the power is low. , LED
The light energy distribution on the photoreceptor surface caused by the light ray is 180 degrees out of phase with the light energy distribution on the photoreceptor surface caused by the semiconductor laser. By adding them together, the final light energy distribution on the photoreceptor surface becomes approximately equal. By doing this, it is possible to obtain a spot with uniform power, and it becomes easier to produce a vector black. Similarly, in FIG. This is the light energy distribution on the surface of the photoreceptor.By reversing the filter sensitivity, it becomes easier to obtain a halftone image and reproduce halftones.In addition, in Fig. 5, (a) shows that Light energy distribution on the body surface (bl is
Light energy distribution (C
) is the light energy distribution on the photosensitive surface superimposed by the semiconductor laser and the LED array, and the transmittance is low in the part facing the center of the photoreceptor and high in the part facing the edge. Therefore, changes in image density due to angle of view can be reduced. Furthermore, in Fig. 6, (al is the light energy distribution on the photoconductor surface by the semiconductor laser (b) is the light energy distribution on the photoconductor surface by the LED array (C) is the superposition of the semiconductor laser and the LED array. This is the light energy distribution on the photoreceptor surface, and a halftone image can be obtained by modulating the light source of the LED array.Here, as shown in the figure, the light energy in the main scanning direction is the integral of the spot. , is different from the light energy in the sub-scanning direction (the direction in which the photoreceptor moves).A filter must be used that takes this into consideration.Here, we assume that the light energy distribution by the LED array is almost uniform, and the transmittance of the filter is However, if the light energy distribution itself emitted from the LED array meets the requirements, the filter may be omitted.

Effects of the Invention A second light source, a filter located in front of the second light source that shapes the light energy emitted from the second light source into a certain pattern of light energy, and the first light source and the second light source. By irradiating the same light onto the same spot, the spot shape can be made into any shape, not just a Gaussian distribution, making it easier to obtain halftone images and reproduce intermediate tones.

Furthermore, any power distribution can be given to the angle of view.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a recording apparatus according to an embodiment of the present invention, and FIG. 2 is a partially detailed diagram of FIG. 1. Figure 3, Figure 4, Figure 5
6A and 6B are distribution diagrams showing the light energy from the semiconductor laser and the LED array and the light energy distribution on the surface of the photoreceptor, and FIGS. 7 and 8 are configuration diagrams of conventional embodiments. ■... Semiconductor laser, 2... Laser light, 3... Control circuit, 6... Rotating polygon mirror, 5, 8... Convergent lens system, 9...
・LED array, 10...filter, 1)・
...Photoreceptor. Name of agent: Patent attorney Toshio Nakao Name: Figure 2, Figure 3, Figure 4, Figure 5, corner of the drawing, Figure 6

Claims (8)

[Claims] (1) A laser as a first light source, a modulating means for modulating the laser beam, a scanning means for scanning the laser beam, and a laser beam generated from the first light source in a main scanning direction and a sub-scanning direction. a lens system that forms an image in a certain diameter spot in a certain direction; a second light source; A filter shaped into a pattern, and an electrophotographic photoreceptor that forms an image corresponding to a light pattern formed by irradiating light from the first light source and the second light source to the same location. Characteristic recording device. (2) The recording apparatus according to claim (1), wherein the filter repeats shading at the same cycle as the resolution determined from the spot diameter in the sub-scanning direction. (3) The second light source does not emit point light, such as a semiconductor laser, but emit line light or surface light, such as an LED array, and the second light source and the filter have a length that is approximately the same as the width of the electrophotographic photoreceptor. The recording device according to claim (1), characterized in that: (4) Claim (1) characterized in that the filter has a low transmittance in a portion facing the center of the electrophotographic photoreceptor and a high transmittance in a portion facing the end portions.
Recording device as described in section. (5) The recording apparatus according to claim (1), wherein the first light source is plural and forms an image corresponding to a light pattern formed by the light sources. (6) The recording apparatus according to claim (1), further comprising a lens system or a lens that forms an image with a certain spot diameter instead of a filter. (7) The modulation means for modulating the laser beam is composed of a memory and a driver, and the laser power is weak in the part facing the center of the electrophotographic photoreceptor and strong in the part facing the edge. The recording device according to claim 1, further comprising a control circuit. (8) The recording device according to claim (1), characterized in that the recording device includes, in place of the filter, a control circuit that can be executed by modulating a laser beam.