JPH05113712A - Recording head positioning method in electrophotographic device - Google Patents

Abstract

PURPOSE:To perform the positioning of a recording head easily with accuracy. CONSTITUTION:In a method of positioning a recording head 3 formed of a light emitting diode 23 and a rod lens array 26 provided at a head body 21, the rod lens array 26 is provided movably in relation to the head body 21, and a first positioning face 36 and a second positioning face 37 are formed in the positions, satisfying a specified expression, of a support body 28 for supporting a sensitized drum 1. At the time of positioning, the rod lens array 26 is brought into contact with the first positioning face 36, and the head body 21 is brought into contact with the second positioning face 37.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of positioning a recording head using a light emitting diode with respect to a photosensitive drum in an electrophotographic apparatus.

[0002]

2. Description of the Related Art There is an electrophotographic apparatus using a photosensitive drum which uses a recording head having a light emitting diode as a light source as an exposing means.

In this type of electrophotographic apparatus, the following process is performed while the photosensitive drum 1 makes one rotation as shown in FIG. The surface of the photoconductor drum 1 is charged by the charger 2, the electrostatic latent image is formed on the surface of the photoconductor drum 1 by the recording head 3, and then the photoconductor drum 1 is formed by the developing device 4.
The electrostatic latent image on the surface of is developed to form a toner image.
On the other hand, the toner image on the photosensitive drum 1 is transferred by the transfer device 5 onto the recording paper 10 delivered from the cassette 9.
The toner image on the recording paper 10 is fixed by the fixing device 6.
In the figure, 7 is a static elimination lamp and 8 is a cleaner.

A recording head 3 having a light emitting diode as a light source used in this electrophotographic apparatus has a structure shown in FIG. In the figure, 21 is a head body forming a horizontally long frame having a length substantially the same as that of the photosensitive drum 1, 22 is a horizontally long wiring board, and 23 is arranged on the wiring board 22 along the axial direction of the photosensitive drum 1. A large number of light emitting diodes provided,
Reference numeral 24 is a light emitting diode driving IC provided on the wiring board 22, and 25 is a radiation fin fixedly provided on the head body 21.

Further, reference numeral 26 is a rod lens array, which is constructed by arranging a large number of rod lenses 27 facing each other in a row of the light emitting diodes 23 and holding them by a frame 26a. A self-focusing rod lens is used for the rod lens array 26, for example. This type of rod lens array 2
The reference numeral 6 has a parabolic refractive index distribution from the central axis of the rod to the periphery thereof, and the light has a function equivalent to that of a lens because it travels in a parabolic shape at a constant interval.

Then, the light emitted from the light emitting diode 23 passes through each rod lens 27 of the rod lens array 26 and is focused on the surface (light receiving surface) of the photosensitive drum 1. By the way, the rod lens 27 used for the rod lens array 26 generally has a shallow focal advance. Therefore, for example, when the rod lens array 26 is fixed and the light emitting surface and the light receiving surface move the same distance with respect to the rod lens array 26, there is almost no deterioration in resolution, but the light emitting surface and the light receiving surface are Is fixed and only the rod lens array 26 is moved, the resolution is significantly reduced. Therefore, when positioning the recording head 3 with the light emitting diode 23 and the rod lens array 26 fixed, the rod lens array 2
High positioning accuracy is required so that the resolution of 6 does not decrease. Conventionally, the following method has been adopted for positioning the recording head 3.

First, when the recording head 3 is set on the support 28 that supports the photosensitive drum 1, positioning is performed. FIG. 5 shows the method. Both ends of the shaft 1a supporting the photosensitive drum 1 are rotatably supported by bearings (not shown) provided on the support body 28. The support 28 is fixed to a main body (not shown) of the electrophotographic apparatus. A positioning surface 29 is formed on the support body 28. The head body 21 of the recording head 3 is brought into contact with the positioning surface 29 of the support 28 to position the recording head 3 with respect to the photosensitive drum 1. This method is positioning of the rod lens array 26 with respect to the photosensitive drum 1.

Therefore, the rod lens array 26 is positioned with respect to the light emitting diode 23 at the factory by the recording head 3.
Are shipped to each of the recording heads 3 at the time of shipping. That is, as shown in FIG. 6, a semitransparent light receiving face plate 30 is provided for the recording head 3, and the light emitted from the light emitting diode 23 is passed through the rod lens array 26 to receive the light receiving face plate 3.
Focus on 0. An image of the light-receiving face plate 30 is projected on a picture tube 33 by a television camera 32 through a microscope 31. Then, the rod lens array 26 is moved to adjust its position so that the spot projected on the picture tube 33 is minimized.

[0009]

However, according to the conventional method, the rod lens array 26 is positioned for each of the three recording heads shipped from the factory. Therefore, the rod lens array 26 positioning operation is performed. It takes a lot of manpower and time. Moreover, since this positioning work adjusts the position of the rod lens array 26 while looking at the spot image projected on the picture tube, it takes a great deal of effort to position the rod lens array 26 with high accuracy. Therefore, there has been a problem that the conventional method of positioning the recording head is very economical.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a recording head positioning method capable of easily and accurately positioning the recording head and improving the economical efficiency of the positioning operation. To do.

[0011]

In order to achieve the above object, a recording head positioning method in an electrophotographic apparatus according to the present invention comprises a light emitting diode and a rod lens for guiding light emitted from the light emitting diode to a photosensitive drum. An array is provided in a head body for positioning a recording head, wherein the rod lens array is movably provided with respect to the head body, and a support for supporting the photosensitive drum satisfies the following formula. A first positioning surface and a second positioning surface are formed at positions, and at the time of positioning, the rod lens array is brought into contact with the first positioning surface and the head body is brought into contact with the second positioning surface. It is what Distance between the central axis of the photosensitive drum and the first positioning surface L1 = Tc / 2 + D / 2-S / 2 Distance between the central axis of the photosensitive drum and the second positioning surface L2 = Tc + D / 2 -L3

Where Tc is the focal length of the rod lens array, D is the diameter of the photosensitive drum, S is the length of the rod lens array in the optical axis direction, and L3 is the distance between the first positioning surface and the light emitting diode.

[0013]

According to the above method, since the rod lens array is positioned at the same time when the recording head is mounted on the support of the photosensitive drum, the rod lens arrays are positioned one by one when the recording head is shipped from the factory. No need for troublesome work. Moreover, the recording head is positioned by contacting the head main body of the recording head with the second positioning surface of the support body and simultaneously contacting the rod lens array with the first positioning surface, whereby the photosensitive drum and the light emitting diode are contacted. Since the mutual positions of the rod lens array and the rod lens array are defined, the rod lens array can be positioned easily and accurately.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 to 4, the same parts as those in FIGS. 5 and 7 are designated by the same reference numerals. The recording head 3 will be described with reference to FIGS.

The recording head 3 is provided with a head body 21, a wiring board 22, a light emitting diode 23, a radiation fin 25 and a rod lens array 26. A holding hole 34 is formed in the head body 21, and the rod lens array 26 is movably fitted in the holding hole 34. Also,
The rod lens array 26 is held by a heat radiating plate 25 by a compression coil spring 35. The rod lens array 26 is provided so as to be movable so that the position of the rod lens array 26 can be adjusted according to changes in conditions such as the diameter of the photosensitive drum 1.

The support 28 for supporting the photosensitive drum includes:
A first positioning surface 36 for contacting the rod lens array 26 of the recording head 3 and a second positioning surface 37 for contacting the head body 21 are formed respectively. The positioning surfaces 36 and 37 have the following positional relationship with the photosensitive drum 1. This point will be described with reference to FIG. L1: the central axis of the photosensitive drum 1 and the first positioning surface 3
Distance between 6 and. L2: central axis of the photosensitive drum 1 and the second positioning surface 3
Distance between 7 and. L3: Distance between the first positioning surface 36 and the light emitting diode 23. L4: central axis of the photosensitive drum 1 and the light emitting diode 23
Distance between. L5: Distance between the center of the rod lens array 26 in the optical axis direction and the light emitting diode 23. L6: Distance between the center of the rod lens array 26 in the optical axis direction and the peripheral surface of the photosensitive drum 1. Tc: focal length of the rod lens array 26. S: Length of the rod lens array 26 in the optical axis direction. D: Diameter of photosensitive drum 1. Basically, the positions of the first positioning surface 36 and the second positioning surface 37 are set so that L5 = L6 = Tc / 2 (1). L3 + L2 = L5 + L6 + D / 2 = L4 (2) L1 + S / 2 + L5 = L4 (3) L2 + L3 = L4 (4) From equations (1) and (2), L3 + L2 = Tc / 2 + Tc / 2 + D / 2 = L4 (5) From equations (1) and (3), L1 + S / 2 + Tc / 2 = L4 (6) From equations (5) and (6), L1 + S / 2 + Tc / 2 = Tc / 2 + Tc / 2 + D / 2 Therefore, L1 = Tc / 2 + D / 2-S / 2. From the expressions (2) and (4), L2 + L3 = Tc + D / 2, and thus L2 = Tc + D / 2−L3. The positions of the positioning surfaces 36 and 37 of the support 28 are set as described above.
A case of positioning the recording head 3 will be described.

The recording head 3 is supported by a compression coil spring 39 attached to a case 38 of the electrophotographic apparatus as shown in FIG. The recording head 3 is set on the support 28 as shown in FIG. That is, as shown in FIG. 4, the surface 21 a of the head body 21 is brought into contact with the second positioning surface 37 of the support body 28. The head body 21 is a compression coil spring 39.
Is pressed and held by the second positioning surface 37.
The rod lens array 26 is pressed against the first positioning surface 36 by the compression coil spring 35, moves in the holding hole 34 of the head main body 21, and the surface 26a is brought into contact with the first positioning surface 36 of the support body 28. Retained.

When the recording head 3 is set on the support 28 in this manner, the head main body 21 is at the position of Tc + D / 2-L3 with respect to the photosensitive drum 1, and the rod lens array 26 is provided on the photosensitive drum 1. On the other hand, Tc / 2 + D / 2
-S / 2 position.

As a result, the relationship of L5 = L6 = Tc / 2 is established, and the positional relationship among the light emitting diode 23 of the recording head 3, the rod lens array 26 and the photosensitive drum 1 is set.

According to the above method, when the recording head 3 is mounted on the support 28 of the photosensitive drum 1, the rod lens array 26 is positioned at the same time. Therefore, when the recording heads 3 are shipped from the factory, the rods are arranged one by one. Lens array 2
The troublesome work of positioning 6 becomes unnecessary. Moreover, when the recording head 3 is positioned, the head body 21 of the recording head 3 is brought into contact with the second positioning surface 37 of the support body 28, and at the same time, the rod lens array 26 is moved to the first positioning surface 3 by the rod lens array 26.
6 to contact the photosensitive drum 1 and the light emitting diode.
Since the mutual positions of the rod 23 and the rod lens array 26 are defined, the rod lens array 26 can be positioned easily and accurately. The present invention is not limited to the above-mentioned embodiment and can be carried out in various modified forms.

[0021]

As described above, according to the recording head positioning method of the present invention, the rod lens array of the recording head is movably provided with respect to the head main body, and a predetermined formula is used in the support for supporting the photosensitive drum. The first positioning surface and the second positioning surface are formed at positions that satisfy the above condition, and the rod lens array is brought into contact with the first positioning surface and the head body is brought into contact with the second positioning surface to position the recording head. Therefore, when the recording head is set on the support of the photoconductor drum, the rod lens array can be positioned easily and accurately, and the rod lens array is positioned one by one when the recording head is shipped from the factory. There is no need, and the economy in positioning the recording head can be improved.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing a state in which a recording head is set and supported on a support according to an embodiment of the present invention.

FIG. 2 is a partially cutaway front view showing a recording head.

FIG. 3 is a side sectional view showing a recording head.

FIG. 4 is an explanatory diagram showing a positional relationship between a recording head and a photosensitive drum.

FIG. 5 is an explanatory diagram showing a conventional recording head positioning method.

FIG. 6 is an explanatory diagram showing a conventional recording head positioning method.

FIG. 7 is a cross-sectional view showing the configuration of a conventional recording head.

FIG. 8 is a diagram showing a schematic configuration of an electrophotographic apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photosensitive drum, 3 ... Recording head, 21 ... Head main body, 23 ... Light emitting diode, 26 ... Rod lens array, 28 ... Support body, 36 ... First positioning surface, 37 ... Second positioning surface.

Claims (1)

[Claims] 1. A method for positioning a recording head, comprising a light emitting diode and a rod lens array for guiding light emitted from the light emitting diode to a photosensitive drum in a head body, wherein the rod lens array is provided in the head body. A first positioning surface and a second positioning surface are formed at positions that are movably provided with respect to the support member that supports the photoconductor drum, and that the rod lens array is positioned at the time of positioning. A method of positioning a recording head in an electrophotographic apparatus, wherein the head main body is brought into contact with the second positioning surface while being brought into contact with the first positioning surface. Distance between the central axis of the photosensitive drum and the first positioning surface L1 = Tc / 2 + D / 2-S / 2 Distance between the central axis of the photosensitive drum and the second positioning surface L2 = Tc + D / 2 -L3 where Tc is the focal length of the rod lens array, D is the diameter of the photosensitive drum, S is the length of the rod lens array in the optical axis direction, and L3 is the distance between the first positioning surface and the light emitting diode.