JP2576474B2 - Light emitting element mounting device for writing - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a device for mounting a light emitting element for writing, and more particularly to a light emitting device in which a light emitting element such as an LED array or a liquid crystal light valve is combined with a selfoc lens. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for mounting a light emitting element for writing in which an element device can be accurately mounted on a drum.

(Prior Art) Conventionally, in a printer or the like, electrically created character or graphic information is converted into optical information, the optical information is irradiated on a drum, and a latent image obtained on the drum is exposed with toner or the like. Some of them adopt a method of developing and printing.

In a printer of this type, a light emitting element device in which a light emitting element such as an LED array or a liquid crystal light valve is combined with a selfoc lens is used as means for converting the electric information into optical information. This light emitting device requires that light emitted from the light emitting device be accurately imaged on the drum.

Conventionally, the light emitting device has been mounted on a frame of a copying machine such as a printer so as to keep a predetermined distance from a drum. However, the tolerance of the focal length of the SELFOC lens is narrow, and there are the following problems.

(Problems to be Solved by the Invention) (1) Since the rotating shaft of the drum is also supported by the frame of the copying machine in the same manner as the light emitting device, the emitting surface of the selfoc lens of the light emitting device, the rotating shaft of the drum and It is difficult to attach the two to the frame so that they are parallel to each other, and it is difficult to focus the Selfoc lens uniformly along the generatrix direction of the drum. For this reason, a clear latent image cannot be uniformly obtained in the generatrix direction of the drum.

(2) It is difficult to make the drum into a perfect cylinder without eccentricity. That is, it is difficult to make the cross section perpendicular to the rotation axis of the drum to be a perfect circle. For this reason, it has been difficult to uniformly focus the selfoc lens in the rotation direction of the drum surface.

(3) When the drum Al pipe is reused,
When the Al pipe is ground and reused, this grinding affects the parallelism of the drum surface, causing a defocus of the Selfoc lens on the drum surface.

An object of the present invention is to eliminate the above-mentioned problems of the prior art,
It is an object of the present invention to keep the distance between the light emitting device and the drum surface constant so that a clear latent image is formed on the drum.

(Means and Actions for Solving the Problems) In order to solve the above problems, the present invention provides a cylindrical drum on which an electrostatic latent image is formed by irradiating an optical image, and a rotating shaft of the drum. A light emitting element array arranged in a direction, optical means for forming an image of light emitted from the light emitting element array on the drum, and the optical means being sandwiched between opposing sides, and perpendicular to the sides. First and second supports having a width in the direction, means for holding the light emitting element array provided on the back surface of the first and second supports, and the other of the first support Means for supporting one side parallel or substantially parallel to the axis of rotation of the drum; and the other side of the second support parallel or substantially parallel to the axis of rotation of the drum, and The torch attached to the part facing the outside of the latent image formation area And a racking roll, wherein the tracking roll is in contact with the drum surface.

(Examples) Hereinafter, the present invention will be described with reference to examples.

FIG. 2 is a sectional view showing a main part of a copying apparatus to which one embodiment of the present invention is applied.

In the figure, reference numeral 1 denotes a drum supported by a rotating shaft 1a and rotating in the direction of arrow A. As shown in the periphery of the drum 1, a charging corotron 2, a light emitting device 3,
A developing device 4, a transfer corotron 5, and a cleaner 6 are provided. Reference numeral 7 denotes print paper, and rollers 8, 9
Is transported in a predetermined direction. Reference numeral 10 denotes a shaft fixedly (or rotatably) attached to the frame, 11 denotes a first support rotatably (or fixedly) attached to the shaft 10, and the first support 11 Are supported with some margin for the frame.

When printing is performed on the print paper 7 by the apparatus having the above-described configuration, an electric signal having print information is applied to the light emitting element device 3. Then, the light emitting element of the light emitting element device 3 blinks according to the electric signal, and the emitted light is imaged on the drum 1 by the selfoc lens.

As a result, an electrostatic latent image is formed on the drum 1, and the latent image is developed by the developing device 4. When the drum 1 further rotates and the developed latent image reaches the position of the transfer corotron 5, the latent image comes into contact with the print paper 7 at this position and is transferred to the print paper 7. The toner remaining on the drum 1 is removed by the cleaner 6, and a new cycle is started.

Since the above is a well-known operation, only a brief description has been given.

Next, an embodiment of the mounting device for a light emitting element for writing according to the present invention will be described in more detail with reference to FIGS. 1 and 3. FIG.
FIG. 1 is an enlarged view of the light emitting device 3 of FIG. 2, and FIG. 3 is a plan view of the light emitting device 3 as viewed from a direction P in FIG.

As shown in FIG. 1, the light-emitting device 3 includes a first support 11 rotatably mounted on a shaft 10 with some margin, and an upper surface of the first support 11. A second support body 12 having an upper surface flush with the above, a reference liner 13 mounted on the first and second upper surfaces, and an LED array 14 having the reference surface supported on the reference liner 13 And a selfoc lens 15 of a predetermined size sandwiched between the first and second supports 11 and 12 to prevent the LED array 14 from entering a heat sink 16 and dust and toner. Cover 17 is attached. Further, the first support 11
The shaft 10 on which is mounted is the frame 19 of the copying machine.
(See FIG. 3). The second support 12 has a pair of tracking rolls 18 at both ends in the longitudinal direction.
Is installed.

As shown in FIG. 1, the pair of tracking rolls 18 are in contact with the drum 1 due to the weight of the light emitting element device 3, and as is apparent from FIG. It is attached to the second support 12 so as to be located outside L. The chain line B in FIGS. 1 and 3
C indicates the traveling direction of light emitted from the LED array and the arrangement direction of the LED array, respectively.

According to the light emitting device 3 having the above configuration,
When the drum 1 rotates during operation, the pair of tracking rolls 18 attached to the second support member rotate while contacting a portion of the drum 1 that does not contribute to the formation of a latent image.

Now, as shown in FIG. ₁ , the distance from the center of the light emitting portion of the LED array 14 to the center of the shaft 10 is l ₁ , and the distance from the center of the light emitting portion to the center of the tracking roll 18 is
l ₂ , even if the tracking roll 18 moves up and down by δ μm during one rotation of the drum 1 due to the eccentricity of the drum 1, the exit surface of the selfoc lens 12 and the drum 1
Distance from the latent image forming surface is {l ₁ / (l ₁ + l ₂ )} × δ (μ
m) Just move up and down. Therefore, the influence of the eccentricity of the drum 1 is reduced to l ₁ / (l ₁ + l ₂ ).

Even if the diameter of the drum 1 changes in the generatrix direction (length direction), the pair of tracking rolls
Since the contact 18 is always in contact with the surface of the drum 1, the distance between the exit surface of the SELFOC lens 12 and the surface of the drum 1 does not change in the generatrix direction, and a clear latent image is formed on the drum. be able to.

Even if dust or the like adheres outside the latent image forming area of the drum 1 and the tracking roll 18 is separated from the drum 1 by δ μm, the change in the distance between the exit surface of the selfoc lens 12 and the surface of the drum 1 is as described above. The effect is similar to the formula and the effect is small.

(Effects of the Invention) As is clear from the above description, according to the present invention, the following effects are achieved.

(1) Since the trunking roll attached to the second support is always in contact with the surface of the drum, even if the diameter of the drum changes in the generatrix direction, light emitted from the light emitting element is transferred to the surface of the drum. They can be uniformly connected in the generatrix direction.

(2) Even if the cross section of the drum cut perpendicular to the rotation axis is not a perfect circle, the defocus on the drum surface due to this is reduced as expressed by the above equation.

[Brief description of the drawings]

FIG. 1 is a side view of one embodiment of the present invention, FIG. 2 is a structural view of a main part of a copying apparatus to which the present invention is applied, and FIG.
FIG. 3 shows a plan view when viewed from the direction of the arrow. 3 ... Light-emitting element device, 10 ... Shaft, 14 ... Light-emitting element, 15 ... Selfoc lens, 18 ... Tracking roll, 19 ... Frame

Claims (1)

(57) [Claims] 1. A cylindrical drum on which an electrostatic latent image is formed by irradiating an optical image, a light emitting element array arranged in a rotation axis direction of the drum, and a light emitted from the light emitting element array. Optical means for forming an image on a drum, first and second supports having a width in a direction perpendicular to the sides, the first and second supports sandwiching the optical means between respective opposing sides; Means for holding the light-emitting element array provided on the back surface of the support, means for supporting the other side of the first support so as to be parallel or substantially parallel to the rotation axis of the drum, A tracking roll attached to a portion of the second support, which is the other side parallel to or substantially parallel to the rotation axis of the drum, and is opposed to a portion of the drum opposite to the electrostatic latent image forming area, Contact the tracking roll with the drum surface Writing emitting element mounting device being characterized in that so as to.