JPH0811349A - Positioning mechanism of image writing head - Google Patents

Abstract

PURPOSE:To set an image writing head to a predetermined angle position by revolving a support member after the distance between the image writing head and a photosensitive drum is determined and fixing a rod by a guide member when the support member is fixed to an apparatus main body. CONSTITUTION:A contact member 4 has a taper part and a flat part 4b and the leading end part 2 of a rod 1 comes into contact with the taper part at first but slides from the taper part toward the flat part 4b. At this time, the leading end part 2 of the rod 1 comes into contact with the flat part 4b being the contact surface of the contact part 4 of a frame and the distance between the surface of a photosensitive drum 3 and a head is determined. However, the head is shifted from the center of the drum from the solid line showing a normal angle by an angle E in this stage because only the rod 1 of the head is energized by a spring 8 and the precision up to a normal angle position is not sufficiently achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to positioning an image writing head such as an LED head or a liquid crystal printer head with respect to an image forming apparatus.

[0002]

2. Description of the Related Art In an image forming apparatus using an electrophotographic system such as an LED printer and a liquid crystal printer, an image writing head such as an LED head is positioned at a predetermined position facing a photoconductor to form an image from a computer or the like. An image is written by controlling the exposure from the head according to a formation signal. These image writing heads are used for image writing because they are used in the vicinity of the photoconductor and are used for a long period of time due to dirt on the head, and when the photoconductor is replaced due to the life of the photoconductor. It is necessary to position the head at a predetermined position or separate it from the photoconductor.

For this reason, for example, as disclosed in Japanese Utility Model Publication No. 6-17551, a positioning rod is provided upright on the writing head, and the tip positioning portion of the rod is brought into contact with the inclined surface of the tip of the recess of the drum support to accommodate the rod. In addition, it has been proposed that the center of curvature of the positioning portion is always positioned on the rotation center line of the drum in the state of being rotatable. FIG. 4 shows a simple explanatory view of the structure.

[0004]

In FIG. 4, the concave groove 1 is formed.
There is a problem that it is difficult to control the focus of each of the support frame 14 of the photoconductor drum 13 and the image writing head in order to focus the image writing head with 1 and the circumferential surface or the spherical surface of the tip 12a of the rod 12. That is, in FIG. 4, the distance L between the tip 12a of the rod 12 and the surface of the photosensitive drum 13 is L.
Is required for focus management, but this distance L will change if the angle of the groove 11 changes like the dotted line. Then, the measurement of the angle of the concave groove 11 cannot be easily performed. Further, if the tip circumferential surface of the rod 12 also changes, the distance L changes. That is, unless the angle of the groove 11 and the circumferential surface or the spherical surface at the tip of the rod 12 are accurately combined, the adjustment work is troublesome.

An object of the present invention is to solve the above problems and to provide a positioning mechanism capable of accurately positioning the writing head for exposure with respect to the photosensitive drum.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides an image forming head having an image writing head for forming a latent image on the surface of a photosensitive drum, and an image forming having the photosensitive drum facing the head. In a positioning mechanism of an image writing head of an apparatus, a supporting member which is attached to the image writing head and urges and supports a rod having a tip portion as a positioning portion by urging the rod toward the photosensitive drum by an elastic member and is rotatable around the apparatus main body. A guide member having a guide surface for guiding the rod and an abutting member for abutting the rod tip portion are provided on a frame supporting the photosensitive drum, the rod is guided by the guide member, and the rod tip portion is abutted. After the distance between the image writing head and the photosensitive drum is determined by contacting the contact member, the guide is used when the support member is rotated and fixed to the apparatus main body. Image write head by the rod is fixed is to be positioned at a predetermined angular position by wood.

[0007]

Since the present invention is configured as described above, the rod supporting the image writing head is guided by the guide member of the apparatus main body supporting the photosensitive drum, and the tip of the rod is also supported by the apparatus main body. After the distance between the image writing head and the photosensitive drum is determined by contacting the contact member, when the rod support member is fixed to the main body of the apparatus, the rod is fixed by the guide member and the image writing head moves to the drum in a predetermined manner. Positioned at an angular position.

[0008]

Embodiments of the positioning mechanism of the present invention will be described below with reference to the drawings.

1 to 3 are schematic explanatory views showing the operation of the positioning mechanism of the present invention.

FIG. 1 shows a state in which the image writing head is separated from the photosensitive drum, FIG. 3 shows a state in which the image writing head is positioned, and FIG. 2 shows a state before the positioning. In the figure, the same parts are given the same numbers. 1 is LE
The rod 1 is a positioning rod that supports an exposure image writing head like a D printer head, and the tip portion 2 of the rod 1 abuts on an abutting member 4 that forms a part of a frame that supports the photosensitive drum 3. It is positioned by being guided by the guide member 5 which is also formed on the frame.

The rod 1 has a center of rotation 6 with respect to the frame.
The rod 1 is attached to the head support member 7 which rotates in the direction of the arrow with the fulcrum as a fulcrum, and the rod 1 is urged by the spring 8 from the support member 7 by the elastic force, and is urged in the direction indicated by the alternate long and short dash line.

The operation of the positioning mechanism of the present invention will be described below with reference to the drawings.

FIG. 1 shows a state in which the head is separated from the photosensitive drum 3. When the head supporting member 7 is pushed down and rotated toward the photosensitive drum 3, the side surface of the rod 1 is guided by the guide surface 5a of the guide member 5 and the tip portion 2 of the rod 1 abuts as shown in FIG. It contacts the contact member 4. As shown in the figure, the contact member 4 has a tapered portion 4a and a flat portion 4b. The tip portion 2 first comes into contact with the tapered portion 4a, but the tip thereof slides by the tapered portion 4a, and the flat portion Slide in the 4b direction. At this time,
The tip portion 2 of the rod 1 contacts the flat portion 4b, which is the contact surface of the contact member 4 of the frame, and the distance between the surface of the photosensitive drum 3 and the head is determined. However, at this stage, the head and the center of the drum are deviated by an angle E from the solid line showing the regular angle. This is because the rod 1 of the head is merely biased by the spring 8 and the accuracy up to the regular angular position cannot be achieved. In the state of FIG. 2, the head support member 7 is still in the middle of rotation and is not fixed to the main body frame. After that, the state in which the support member 7 further rotates and is fixed to the frame is shown in FIG. 3, and the positioning is completed in this state. In FIG. 3, the distal end portion 2 of the rod 1 is fixed by the contact member 4, but the angle is further fixed by the guide member 5. That is,
When the support member 7 rotates to the regular position and is closed by the main body, the spring 8 contracts, the inclination corresponding to the angle E disappears, and the distance and the position of the angle are determined. The guide surface 5a of the guide member 5 prevents the rod 1 from being further tilted by minus E degrees.

When the positioning mechanism is constructed as described above, the height of the abutting surface of the rod 1 can be easily measured because it can abut the flat portion 4b even though it has the tapered portion 4a, so that the dimension on the frame side can be easily obtained. . Also, the head side is rod 1
Since the shape of the tip portion 2 of (1) does not necessarily have to be a circumferential surface or a spherical surface, it can be measured at the tip of the rod, so focus adjustment is easy. Therefore, it is possible to freely combine the frame and the rod 1 by controlling the dimensions of the rod 1 and the contact member 4, respectively.

[0015]

As described above, according to the positioning mechanism of the present invention, it is possible to easily control the dimensions and position the image writing head and the photoconductor at a regular distance and angle.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an operation of a positioning mechanism of the present invention.

FIG. 2 is a schematic explanatory view showing the operation of the positioning mechanism of the present invention.

FIG. 3 is a schematic explanatory view showing the operation of the positioning mechanism of the present invention.

FIG. 4 is an explanatory view of a main part showing a conventional positioning mechanism.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 rod 2 tip part 3 photoconductor drum 4 contact member 4a taper part 4b flat part 5 guide member 5a guide surface 6
Rotation center 7 Support member 8 Spring 11 Recessed groove 12 Rod 12a
Tip 13 Photoconductor drum 14 Support frame

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H04N 1/032 Z

Claims (1)

[Claims] 1. An image writing head for forming a latent image on the surface of a photosensitive drum, and an image writing head positioning mechanism of an image forming apparatus having the photosensitive drum facing the head, wherein the image writing head is attached. And a guide for guiding the rod to a frame supporting the photoconductor drum, and a supporting member that urges and supports the rod whose tip is a positioning part in the direction of the photoconductor drum by an elastic member and is rotatable around the apparatus main body. A guide member having a surface and an abutting member that abuts on the rod tip end portion are provided, and the rod is guided by the guide member and the rod tip end portion abuts on the abutting member so that the distance between the image writing head and the photosensitive drum. Once the support member rotates and is fixed to the main body of the apparatus, the rod is fixed by the guide member and the image writing head is There the image write head positioning mechanism, characterized in that it has to be positioned at a predetermined angular position.