JPS63109417A - Light source device - Google Patents

Abstract

PURPOSE:To reduce the size of a light source device and to attain power saving by radiating a fine area in a long range by a converging plate member for collecting light beams from one or plural exposing means by its face part and radiating the beams from its edge. CONSTITUTION:One or plural non-linear light sources 21 and the flexible plate member 20 having characteristics for receiving and absorbing light rays (ultraviolet rays) projected from the light sources 21, radiating fluorescent light in its inside, converging the light into the linear edge by full reflection and then transmitting the converged light are used for the light source device for radiating a modulating element array 12. The non-linear light sources 21 are non-linear light source such as LEDs and plural non-linear light source are arranged in parallel in the depth direction rectangular to paper face. The plate member 20 is set up so as to just cover the shutter array 12 at its edge part and can be bent so as to reduce its capacity because the member 20 consists of flexible plastic. Consequently, a long linear light source can be omitted, power saving can be attained and the depth of a printer head can be reduced. Since no head is generated, the plate member 20 can be made close to relating members and the printer head can be reduced at its size.

Description

Detailed Description of the Invention 41 Object of the Invention [Field of Industrial Application] The present invention relates to a light source device that illuminates a minute area over a long length; The present invention relates to an exposure light source device for a head.

[Conventional technology]

With the recent development of information processing technology, the amount of information has increased, and the amount of information on a personal basis has also increased. This has led to further personalization of information processing devices, and these devices are being actively developed.

The equipment was required to be small and inexpensive, but recently there has been a desire for higher speed and higher quality.

One of these information processing devices is a printer. Among these printers are electrophotographic printers that are excellent in terms of high speed and high image quality. Among them, printers using solid-state scanner printer heads, which can be made more compact, are attracting attention.

A solid-state scanner is one in which minute light emitting elements (for example, light emitting diodes: LEDs) or light modulation elements (for example, liquid crystal shutters) are arranged in an array for one image forming width.

The cheapest type of solid-state scanner is a liquid crystal shutter array.

FIG. 5 shows a schematic configuration diagram of an electrophotographic printer using a liquid crystal shutter array optical printer head.

IO is a liquid crystal shutter array optical printer head, and light source 1
1. Consists of a liquid crystal shutter array 12 incorporating a drive circuit 15 and an imaging lens (convergent lens array: trade name Selfox Lens Array: hereinafter abbreviated as SLA) 13. The liquid crystal shutter array 12 is formed by arranging fine liquid crystal shutters in an array, and creates a light image according to an information signal by controlling whether the light from the light source 11 is transmitted or not transmitted by the shutter.

At 5LA13, the surface of the light image is uniformly charged by the charger 2 and formed on the photosensitive drum l rotating in the direction of the arrow, forming a latent image, which is developed by the developing unit 3 and transported in the direction of the arrow B. The image is transferred onto a sheet of paper by a transfer device 4, and further fixed by a fixing unit 5 to form an image on the sheet. Further, 6 is a cleaning device for cleaning the surface of the photoreceptor. After this cleaning, return to the first process. Reference numeral 8 is a sheet a placement table, and 7 is a registration roller for feeding the sheet to the transfer section at an appropriate timing.

As described above, when a solid-state scanner is used, there are no mechanically moving parts compared to the conventional laser system, and there are advantages such as miniaturization and improved reliability.

[Problem that the invention seeks to solve]

However, in recent years, as electrophotographic apparatuses have become more compact, there has been a desire for scanners to be further miniaturized.

What hinders miniaturization of the conventional device shown in FIG. 5 is the light source 11, which is comprised of a fluorescent lamp or the like.

Figure 6 shows the special light distribution (luminance distribution in the longitudinal direction) of a typical fluorescent lamp.As is clear from this, because there is a filament at the end of the tube, the brightness drops rapidly, and the brightness is uniform. In order to illuminate the surface, the center part must be used, excluding the edges, and as a result, a long light source is required (for example, 210 mm).
In order to uniformly illuminate the area of 3 mm, including the socket part, approximately 3
(50 ta layer light source must be used), and the width of the entire device (depth width in FIG. 5) becomes large.

Furthermore, devices that generate heat, such as fluorescent lamps, have an adverse effect on the liquid crystal, so the distance between the device and the device must be kept to a certain extent, which hinders miniaturization of the device.

The present invention eliminates the drawbacks of the above-mentioned conventional example, thereby reducing the size of the light source device and also making it possible to save power.

The purpose is to provide a light source device suitable for application to personal equipment.

Summary: Structure of the Invention [Means for Solving Problems] The present invention illuminates a minute area over a long range using a condensing plate member that collects light from one or more exposure means at a surface portion and radiates it from an edge. This is a light source device characterized by:

[For production]

Using a condensing plate member that takes in light from the surface and emits light from the edge, it absorbs light from a non-linear light source such as an LED or an exposure means such as external light from the surface, emits it from the edge, and displays the liquid crystal. It illuminates a fine area such as a shutter array over a long range.

〔Example〕

FIG. 1 of the present invention shows an example in which the light source device of the present invention is applied to the light source of the printer head 10 of the electrophotographic printer shown in FIG. one or more non-linear light sources 21;
The purpose is to use a flexible plate member 20 that has the property of receiving and absorbing the light (ultraviolet a) on its surface, emitting it as fluorescence internally, and converging the light to an edge (linear) through total reflection and propagating it. .

A plurality of non-linear light sources 21, such as LEDs, are installed in parallel in the depth direction perpendicular to the paper surface. Reference numeral 20 denotes the above-mentioned plate member, which is set so that its edge portion just covers the liquid crystal shutter array 12. This plate member 20
They are usually made of thin plastic and are flexible, so they can be bent to reduce their volume as shown.

This plate member, whose trade name is LiSA, is made of transparent plastic and fluorescent dye, absorbs direct light and dispersed light from the surroundings, and radiates it as fluorescence inside the plastic. Due to total internal reflection, the fluorescent light travels to the edges of the plastic panel, where it emits fluorescent light. In order to change the properties of light in this way, light with a wavelength of 370 nm or more is used.

FIG. 4 shows how the projected light is absorbed by a very pure fluorescent dye. Fluorescent light is emitted randomly within the plastic panel, and due to the law of total internal reflection, a portion of the projected light passes through the panel at F2. F3, F4, and so on, and the remaining Fl passes through the capture area and escapes from this plastic panel.

The ratio of fluorescence F2, F3, and F4 to the total projected light depends on the refractive index of the plastic and is expressed by the following equation.

(n2-1) Σ(F2, F3, F4)±□ (F2, F3, F4) reaches 70-80%. 100
If 25% of the light photons hit the plastic panel, 25% will be emitted out of the plastic panel, and of the 75% of the light that passes through the panel, 20-30 will be reabsorbed by the dye, resulting in a failure of 10.5% to the optimal condition. Approximately 40 photons are transported to the edge and emitted from it. The intensity of this light is proportional to the width of the panel.

21 is a non-linear light source attached to this plate member,
The figure shows an LED. In this case, due to the nature of the plate member 20, one with a short emission wavelength (currently commercially available ones are around 570 ns) is most efficient.

According to experiments, when EDs 21 are arranged at intervals of 3 to 5 cm, the light distribution from the edge portions of the plate member 20 is sufficient for practical use, and the decrease in brightness at the edge portions is less than that of fluorescent lamps. I understand.

In the above example, a plurality of non-linear light sources 21 are simply used as light source devices.
and a light-guiding fluorescent plate 20, the surface of this plate 20 is exposed to the outside of the device by making the most of the characteristics of absorbing light and emitting it as fluorescence.
By using external light and light source light in parallel, further power savings can be achieved.

FIG. 2 shows a schematic diagram of this embodiment. In other words, a part of the surface of the plate member 20 is exposed to the outside of the device, and external light from outside the device is also absorbed by the plate member and guided to the liquid crystal shutter surface. be. In addition, numeral 21 indicates the plurality of LED light sources mentioned above, which in this case serve as auxiliary light sources to compensate for the insufficient amount of external light.This allows the power consumption of light sources such as LEDs to be reduced, making it more personalized. It becomes possible to manufacture devices such as

In this configuration, it is necessary to control the lighting of the auxiliary light source 21 in order to always keep the amount of light constant even on the liquid crystal shutter surface even in the face of unstable external light.

FIG. 3 shows a block diagram of an example of the control means. Immediately before an image is formed on the photoreceptor 1 by the printer 10,
The liquid crystal shutter 12 in the head 10 is opened by the drive circuit 15, and the surface potential of the photoreceptor at that time is detected by the surface potential sensor 30.
The results are converted into digital data by the A/D converter 31 and processed by the microprocessor unit M in the main body.
The light source lighting control circuit 33 changes the duty ratio of the LED, which is the light source 21, according to the data.

This allows the amount of light emitted by the auxiliary light source 21 to be controlled according to changes in outside light, and the amount of light emitted from the shutter illumination surface (light emitted from the edge of the plate member) to be always stable, thereby forming a stable image at all times. It becomes possible to do so.

Further, in the above example, the case where there is one surface potential sensor 30 has been described, but by providing a plurality of these in the main scanning direction (the depth direction in the figure) and controlling the light source corresponding to each, shutter exposure can be achieved. The uniformity of brightness in the main scanning direction can be improved, and a stable image can always be obtained over the entire width.

In addition to the method of detecting the photoreceptor surface potential described above, the plate member 2
Detects the amount of light emitted from the end of 0, and uses that signal to control LED2
1 may be controlled.

Furthermore, the present invention is not limited to the application of liquid crystal shutter arrays or other light modulation element arrays (for example, Kerr effect shutter arrays, etc.) to exposure devices, but can be applied as a light source device for ordinary document exposure, etc. .

C1 As described in detail in the invention, a light-concentrating resin that collects light from one side and radiates it from the edge as part of a light source equipment that illuminates a minute area over a long range, such as a light modulation element array. By using the plate member, a long linear light source is no longer necessary, and only a few to 10 LEDs are sufficient as the light source, resulting in power saving and the depth of the printer head can be reduced. In addition, since no heat is generated, the plate member can be placed close to related members, which results in the miniaturization of the printer head, which has a great effect on the personalization of information processing equipment to which this is applied.

Further, if external light is used as the illuminating surface means of the light-condensing resin plate member as in the embodiment, the power consumption of the illuminating surface means can be further reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an image forming apparatus showing a first embodiment of the invention, FIG. 2 is a schematic diagram of an image forming apparatus showing an MS2 embodiment of the invention, and FIG. 3 is a second embodiment of the invention. 4 is a diagram explaining the principle of the light-concentrating resin plate member used in the present invention, FIG. 5 is a schematic diagram of a conventional image forming apparatus, and FIG. 6 is a diagram showing the light distribution of a fluorescent lamp. It is a graph showing characteristics. l...Photoreceptor, 10...Printer head, 12...
- Light modulation element, 13...imaging lens, 15...circuit for driving the light modulation element, 20 is a condensing plate member, 21...
Non-linear power supply, L...External light. Figure 3 Figure 4 Figure 1 Figure 2

Claims (3)

[Claims] (1) A light source device characterized in that a minute area is illuminated over a long range by a condenser plate member that collects light from one or more exposure means at a surface portion and radiates it from an edge. (2) The light source device according to claim (1), wherein at least one of the plurality of exposure means is an external light utilization means, and the others are auxiliary exposure means for the external light exposure means. (3) A light source according to claim 1, wherein one of the exposure means uses external light, detects a change in the amount of external light, and controls the exposure amount of the auxiliary exposure means based on the output thereof. Device.