JPS6127268A - recording device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Technical field The present invention relates to an electrophotographic recording device used as a writing means.

Conventional technology A manuscript is scanned with a photoelectric element and read as black and white dots.
A binary on/off signal is generated for each dot, and a large number of light emitting diodes (light emitting diodes) are connected in parallel to the scanning direction of the photoreceptor.
Printers, copiers, facsimile machines, etc. that perform recording using an electrophotographic process by sequentially inputting information to each LED of an LED array (hereinafter abbreviated as LED) and blinking it to form an image on the surface of a photoreceptor to perform optical writing and recording using an electrophotographic process. A recording device that outputs a hard copy of is known.

FIG. 5 is a diagram showing the configuration of a main part of a known recording device using an LED array as an optical writing means. Many LEs
An LED array 1 is formed by arranging LEDs D3 in a line on one surface of a substrate 2, with the surface where the LEDs 3 are arranged facing the exposure scanning position 5 of the photoreceptor drum 4, and the row of LEDs 8 being parallel to the scanning direction. Each LED of LED array 1
The light emitted from the L
The image is projected onto the exposure position on the surface of the photoreceptor 4 via a bar lens 6 provided parallel to the ED row. The photoreceptor drum 4 is main-scanned by sequentially blinking the LEDs 3 of the LED array 1 in accordance with the image signal, and the photoreceptor drum 4 is sub-scanned by rotating in the direction shown by the arrow in the figure. An electrostatic latent image corresponding to an image signal is formed by a collection of latent images of dots on the photosensitive drum 4, which is uniformly charged. This latent image is visualized as a toner image by the developing device 8 and transferred onto the transfer paper 10 by the transfer charger 9. The transfer paper onto which the toner image 11 as a collection of dots has been transferred is separated from the photosensitive drum and fixed by a fixing device (not shown) to complete the recording.

An electrophotographic recording device with such a configuration does not require a precision high-speed scanning system such as a rotating polygon mirror or an f-theta lens used as a main scanning means in the case of a laser beam printer, and can be It has the advantage that it can be expected to be inexpensive.However, on the other hand, the LEDs 3 that make up the LED array 1 are very small, and although they are shown large in the figure for convenience, they are actually 0 points about 50 μm square, and it is difficult to develop. If toner particles scattered from the device 8 adhere to the light emitting surface of the LED 8, the light emitting surface of the LED 8 will be optically covered, and pixels will not be written normally.

As a means for preventing toner stains on the LED array, Japanese Patent Laid-Open No. 57-68867 discloses a method as shown in FIG.
A sealing member 12 is provided on both sides of the row of LEDs 8 between the facing surfaces of the D array 1 and an elongated imaging optical element 6 such as a bar lens, and a sealing member 12 is provided on both sides of the row of LEDs 8 between the opposing surfaces of the D array 1 and an elongated imaging optical element 6 such as a bar lens. A configuration is disclosed in which a space surrounded by the entrance surface of No. 6 and the sealing member 12 is completely isolated from the outside space. Although this configuration can certainly prevent toner particles from adhering to the light emitting surface of LED 3 of LED array 1,
The heat generated when electricity is applied to the LED is accumulated in this space.
The surrounding temperature increases. The relationship between the ambient temperature and the amount of light when a constant voltage is applied to the LED is shown in FIG. 7 as an example, and it is known that as the ambient temperature increases, the amount of light decreases linearly. Therefore, as shown in Figure 2 (L
The surface provided with the LED light emitting surface of the ED array and the imaging optical element 6
If the gap with the entrance surface of the LEIE is completely sealed with the sealing member 12, the light emission amount of the LEIE will decrease due to the rise in the temperature around the LED.
This in turn causes a decrease in the image density on the record.

Purpose: In view of the above-mentioned drawbacks of the conventional means for preventing toner adhesion to the LED light emitting surface of a recording apparatus having an optical writing device using an LED array, the present invention provides a simple structure that does not cause an increase in the ambient temperature of the LED. (An object of the present invention is to provide an electrophotographic recording device that can prevent toner particles from adhering to an LED light emitting surface.

Structure In order to achieve the above object, the present invention provides toner adhesion prevention members on both sides of the LED row between the opposing surfaces of the LED array and the imaging optical element, and between the internal space and the external space. The present invention is characterized in that a gap is provided to allow air circulation to prevent the ambient temperature of the LED from rising beyond the permissible range during writing.

With this configuration, an increase in the LED ambient temperature is prevented, and a decrease in the amount of light and a decrease in recorded image density due to the increase in the ambient temperature is avoided.

Hereinafter, the present invention will be explained in detail based on the drawings.

In the embodiment shown in FIG. 1, toner adhesion prevention members 14 are provided on both sides of the row of LEDs 3 on opposing surfaces of the LED array 1 and the imaging optical element 6.

One end of the toner adhesion prevention member 14 is fixed to both side edges of the imaging optical element 60, and an outwardly protruding flange is provided at the other end, and optical writing is performed between the toner adhesion prevention member 14 and the surface of the LED array 10. A gap S is provided to allow sufficient air circulation to prevent the ambient temperature of the LED from rising beyond a predetermined allowable range even when the LED generates heat.

With the above configuration, adhesion of toner particles to the light-emitting surface of the LED 3 is virtually completely prevented, and at the same time, the air whose temperature has increased due to the heat generated when the LED is energized during optical writing is removed from the LED 3. Array 1 and toner adhesion prevention member 14
Since heat escapes through the gap S between the LED and the upper end by communicating with the outside air, a decrease in the amount of light caused by an increase in the temperature around the LED does not occur.

Note that since no measures are taken to prevent toner adhesion on the exit surface side of the imaging optical element 6, there is a possibility that toner particles 13 may adhere to this surface, but the adhered toner may be formed on the photoreceptor surface. The influence on the light intensity reduction of the spot is determined by the ratio of the aperture area of the imaging optical element and the toner stain area, so the LE
This is incomparable to the influence of toner adhesion to D and can be ignored.

In the embodiment shown in FIG. 2, the toner adhesion prevention member 15 is
It is fixed to both sides of the ED array 1, and an appropriate gap S' is provided between the other end and the imaging optical element 6.

Therefore, toner adhesion to the LED light emitting surface is prevented,
Air whose temperature has increased due to the heat generated by energizing the LED during optical writing passes through this gap and interacts with outside air to prevent the ambient temperature of the LED from rising. Furthermore, in this case, the toner adhesion prevention member 15 is made of a material with a high heat dissipation ratio, such as aluminum, and has a shape with a large surface area, such as having seven lunges as shown in the figure, so that heat dissipation from the LED can be promoted.

The embodiment shown in FIGS. 3 and 4 shows an example in which a focusing transmitter array 16 is used in place of the bar lens as the imaging optical element. Similar functions and effects can be obtained by installing toner adhesion prevention members 14 and 15 in the same manner as in the illustrated example.

Effects As described above, according to the present invention, it is possible to prevent toner particles from adhering to the LED light emitting surface of the LED array with a simple configuration, thereby preventing optical writing errors, and also to prevent an increase in the LED ambient temperature during optical writing. This can also be prevented and the quality of recording can be improved.

[Brief explanation of the drawing]

1 to 4 are sectional views showing embodiments of an optical writing device provided with a toner adhesion prevention member according to the present invention, and FIG. 5 is an electrophotographic recording device having an optical writing device using a known light emitting diode array. FIG. 6 is a sectional view showing an example of a conventionally proposed toner adhesion prevention means, and FIG. 7 is a curve diagram showing an example of the relationship between the ambient temperature and the amount of light of a light emitting diode. . l...Light emitting diode array 3...Light emitting diode (LED) 4...Photoreceptor 6...Bar lens (imaging optical element) 14.15...Toner adhesion prevention member 16...Focusing property Optical transmitter array (imaging optical element) s
, s'... Gap Figure 1 Figure 3 Figure 2 Figure 4

Claims (3)

[Claims] (1) A light emitting diode array in which a large number of light emitting diodes arranged parallel to the photoreceptor scanning direction are sequentially driven by image signals to blink, and a space between the surface of the light emitting diode array on which the light emitting points are provided and the surface of the photoreceptor. An electrophotographic recording device comprising: an optical writing device having an elongated imaging optical element that extends parallel to the light emitting diode array and forms an image of light emitted by the light emitting diodes on the surface of a photoreceptor; A toner adhesion prevention member is installed on both sides of the light emitting diode array between the surfaces facing each other with the above-mentioned imaging optical element, and between the internal space and the external space, the ambient temperature of the light emitting diode during optical writing exceeds the permissible range. 1. A recording device characterized in that a gap is provided to allow air to circulate to prevent the air from rising. (2) The recording apparatus according to claim 1, wherein the toner adhesion prevention member is attached to the imaging optical element. (3) A recording device according to claim 1, characterized in that the toner adhesion prevention member is made of a material with a high heat radiation ratio, formed in a shape that has a large heat radiation area, and is attached to a light emitting diode. .