JPH09269548A - Focusing method for exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily focus in a short time without uselessly and repeatedly adjusting a lens mount angle by displaying the adjustment results as for a lens rotating direction and the lens mount angle at focusing. SOLUTION: A sensor 29 is set to the mount part of a photoreceptor drum 8 in a state where an exposure device other than the photoreceptor drum 8 is assembled with the device main body, and based on a difference of the resolution comparison result, such a command is outputted by a computer 30 to a driving means 31 that not only a lens center adjustment mount, but also a lens should be shifted in any direction and by any angle so that the resolution difference may be within a prescribed extent. And the lens mount angle is automatically changed based on the resolution comparison result, and focusing on parts corresponding to both longitudinal sides of a slit exposure area is automatically executed. In this case, the automatic focusing result, that is, in which direction the lens was shifted and how many angles the lens was shifted are displayed on the monitor 33 of the computer 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focusing method for an exposure device equipped in an image forming apparatus such as an electrostatic photocopier and a facsimile.

[0002]

2. Description of the Related Art As an exposure apparatus of the above image forming apparatus, a so-called lens in which a mounting angle can be changed around a vertical axis is moved in the optical axis direction so that a document image is slit-exposed on a photosensitive surface at different magnifications. Some have a scaling function.

In the exposure apparatus having such a configuration, the resolutions of the images on both sides in the longitudinal direction of the slit exposure area exposed on the photosensitive surface are compared, and the vertical axis is set so that the difference in the resolutions falls within a predetermined range. By changing the mounting angle of the lens (direction of the center of the lens), so-called focusing can be performed.

In reality, the original image is exposed on the photosensitive surface, the latent image on the photosensitive surface is developed to make it visible, and the toner image is transferred and fixed on a recording paper, and the result is used as a basis. To visually detect the difference in resolution, adjust the lens mounting angle based on the detection result of this resolution, and again perform the exposure and development, and transfer / fixing processing to confirm that focusing is complete. The work of visually detecting the difference in resolution is performed. When the focusing is insufficient, the above work is repeated.

[0005]

However, it is very difficult for even a skilled person to change the mounting angle of the lens based on the difference in resolution visually detected and relying on intuition. However, it takes a very long time to achieve the desired focusing. Further, while the lens angle adjustment is being repeated, the adjustment result previously made is often forgotten, and the adjustment work may be repeated in vain.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention makes it possible to visually grasp the adjustment results of the lens rotation direction and the lens mounting angle when focusing is performed. The purpose is to be able to greatly reduce the focusing adjustment time.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION That is, the present invention compares the resolutions of images on both sides in the longitudinal direction of a slit exposure area exposed on a photosensitive surface, and mounts a lens so that the difference in resolution is within a predetermined range. In the focusing method for adjusting the angle, the adjustment result of the lens rotation direction and the lens attachment angle at the time of focusing is displayed.

According to such a focusing method, it is possible to visually manage the adjustment result of focusing, that is, in which direction and how much the lens has been changed. However, it is possible to easily perform focusing in a very short time without needlessly repeating the adjustment.

Further, since it is possible to grasp the degree of deviation of the lens assembling on the line based on the display of the adjustment result, the adjustment result can be used as a guideline for improving the work form, or, for example, money can be used. Since the finish tendency of the molded product can be grasped, the above adjustment result can be used as a standard for the improved design of the mold.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an exposure device equipped in the image forming apparatus, which projects light reflected from the document surface in the arrow direction P through a light source 1 for exposing the document, a reflector 2, and an exposure slit a. The first mirror 3 is provided on each of the first moving frames 4, and the second and third mirrors 5 and 6 for sequentially reflecting the reflected light from the first mirror 3 and projecting the reflected light in the arrow direction Q are provided.
The fourth to sixth mirrors 9 to 11 provided on the movable frame 7 and sequentially reflecting the reflected light from the third mirror 6 and projecting the reflected light on the photosensitive surface of the photosensitive drum 8 are fixed to the apparatus main body 12 side. An optical lens unit 13 that is provided and slit-exposes the original image on the photosensitive surface through the slit a is reciprocally movable in the optical axis direction between the third and fourth mirrors 6 and 9 so that the projection magnification can be changed. And a light amount correction device 14 for correcting the projection light amount on both sides in the longitudinal direction of the slit exposure area according to the change of the projection magnification.

As shown in FIGS. 2 to 4, the above-mentioned light quantity correction device 14 swings in the direction in which the optical path of the lens 15 is blocked, and a pair of metals for correcting the projection light quantity on both sides in the longitudinal direction of the slit exposure area. Manufactured light amount correction plates 16, 16 and the light amount correction plates 16, 16 in accordance with the lens movement in the direction of reducing the projection magnification.
And a tilt guide member 17 made of synthetic resin for swinging 16 toward the lens center side. The light amount correction plates 16 and 16 therein are integrally provided on the optical lens unit 13 side, and the tilt guide member 17 is provided. , 17 are provided on the apparatus body 12 side.

The optical lens unit 13 is mounted on a pair of guide rails 18 and 18, for example, via a wire type transmission means 19 and a stepping motor 20, and based on setting information of the variable magnification. It is adapted to be reciprocally moved in the optical axis direction by an amount corresponding to the magnification.

Specifically, the optical lens unit 13
Is a lens pedestal 21 that is mounted on a pair of guide rails 18 and 18 and that can reciprocate in the optical axis direction, and is rotatable and fixed around a positioning vertical axis 22 that is erected on the lens pedestal 21. A lens center adjustment base 24 fixed by means 23, and a lens frame 25 equipped with the lens 15 and mounted and fixed on the lens center adjustment base 24 by a fixing screw b.
5 and, as shown in FIG. 5, one end side of the lens center adjustment base 24 (the third mirror 6 side in the illustrated example, but may be the fourth mirror 9 side) may be downward. The bent plate portion 24a is provided with the pair of light quantity correction plates 16 and 16 after being bent.

The pair of light amount correcting plates 16 and 16 are pivotally attached to the center side of the bending plate portion 24a via a support shaft 26 in the optical axis direction, and guides formed around the support shaft 26. A guide pin 27 fixed to the bending plate portion 24a is inserted into the groove c, and a correction plate holding member 28 that holds the guide plate c around the guide groove c of the light amount correction plate 16 by the bending plate portion 24a is further provided. A screw d is fixed to each of the support shaft 26 and the guide pin 27. Then, the lower part of the light amount correction plate 16 on the free end side is bent in the horizontal direction, and the bent plate portion 16a is mounted on the inclined guide member 17.

According to the above arrangement, based on the setting information of the scaling ratio, as the optical lens unit 13 moves in the optical axis direction by the dimension corresponding to the scaling ratio, the fixed shaft by the support shaft 26 is fixed. A pair of light amount correction plates 16, 16 supported at two points by the landing point and the guide pin 27 swing around the fixed pivot point. When the optical lens unit 13 is moved in the direction of reducing the projection magnification, the light quantity correction plates 16, 1
6 swings toward the lens center, and when the optical lens unit 13 is moved in the projection magnification expanding direction, the light amount correction plates 16 and 16 swing so as to move away from the lens center, and the projection magnification is changed. By correcting the projected light amounts on both sides in the longitudinal direction of the slit exposure region, the light amount distribution in the longitudinal direction of the slit exposure region is made uniform.

As the light quantity correction device 15, two light quantity correction plates 16 and 16 are provided.
Each of 16 is supported at two points, and one of the supporting points is used as a fixed pivot point by the support shaft 26, and the optical lens unit 1
Although the light quantity correction plates 16 and 16 are swung around the fixed pivot point in accordance with the movement of 3, the light quantity correction plates may be moved up and down by an inclined guide member, for example.

When the mounting angle of the lens 15 is changed to focus the portions corresponding to both sides in the longitudinal direction of the slit exposure area, the lens center adjusting base 24 is fixed by the fixing means 23, Lens frame 25
The lens center adjustment base 24, on which the light amount correction plates 16 and 16 are integrally mounted and fixed, is changed in posture around the vertical axis 22. As a result, as is apparent from FIG. , 16 and the lens 15 are kept unchanged, and therefore focus adjustment can be performed without causing a difference in light amount correction on both sides in the longitudinal direction of the slit exposure region.

7 and 8 show an example of an automatic focusing device. This device includes, for example, a CCD sensor 29 that detects the resolution of an image on both sides in the longitudinal direction of a slit exposure area that is exposed on a photosensitive surface, a computer 30 that inputs a detection result of the resolution, and compares the resolutions. Lens center adjustment base 2
4 and a drive means 31 for rotating the shaft 4 around the vertical axis 22, and the entire apparatus is configured to be handled as a jig unit.

The sensor 29 is set in the mounting portion of the photoconductor drum 8 in a state where the exposure device excluding the photoconductor drum 8 is incorporated in the apparatus main body 12, and the difference in the comparison result of the resolution is displayed from the computer 30. On the basis of this, the lens center adjustment base 2 is set so that the difference in resolution is within a predetermined range.
4 and by extension, a command for changing the angle of the lens 15 in which direction is output to the driving means 31.

The driving means 31 has an operating shaft 32 which can be inserted into and removed from a pin hole e formed in the lens center adjusting base 24, and the driving means 31 itself reciprocates in the optical axis direction by a stepping motor or the like. It is configured to be possible.

According to the above arrangement, the mounting angle of the lens 15 is automatically changed based on the result of the resolution comparison without forming the original image on the recording paper, and both sides of the slit exposure area in the longitudinal direction. Is automatically performed, and the monitor 33 of the computer 30 displays the result of automatic adjustment of focus, that is, in which direction and how much the lens 15 has been changed. To be done. Of course, the display result can be hard-copied, or the adjustment result stored in memory can be printed out.

The mounting angle of the lens center adjustment base 24 may be adjusted artificially, and a dial gauge may be brought into contact with the lens center adjustment base 24, for example.
The adjustment result may be displayed in an analog manner.

In the above embodiment, the lens cradle 2 is used.
The vertical axis 22 is erected on the upper surface of the lens 1, and the lens center adjustment base 24 can be rotated and fixed around the vertical axis 22. The vertical axis 22 is hung on the lower surface side of the lens center adjustment base 24. The lens center adjusting base 24 may be provided so as to be rotatable and fixed with respect to the lens receiving base 21 by forming an insertion hole of the vertical axis 22 in the lens receiving base 21.

[0024]

The present invention is carried out in the form as described above, and compares the resolutions of images on both sides in the longitudinal direction of the slit exposure area exposed on the photosensitive surface, and the difference in the resolutions is determined by a predetermined value. In the focusing method that adjusts the mounting angle of the lens so that it falls within the range, the rotation direction of the lens and the adjustment result of the lens mounting angle at the time of focusing are displayed, and the adjustment result of the focusing, that is, Since it is possible to visually manage which direction and how much the lens has been changed, even if you are unfamiliar with the adjustment, the lens can be adjusted by using the focus adjustment result. It is now possible to focus easily in a very short time without needlessly repeating the adjustment of the mounting angle.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional side view of an exposure apparatus.

FIG. 2 is a plan view of an optical lens unit and a light amount correction device.

FIG. 3 is a side view of an optical lens unit and a light amount correction device.

FIG. 4 is a detailed front view of the light quantity correction device.

FIG. 5 is an exploded side view of the optical lens unit.

FIG. 6 is an explanatory diagram showing a state of focusing.

FIG. 7 is a configuration diagram of an automatic focusing device.

FIG. 8 is an explanatory diagram of automatic focusing.

[Explanation of symbols]

 15 ... Lens, 22 ... Vertical axis.

Claims (1)

[Claims] 1. A focusing method for an exposure apparatus, wherein a lens whose mounting angle is changeable about a vertical axis is moved in the optical axis direction to slit-expose a document image on a photosensitive surface at different magnifications. Compare the image resolution on both sides in the longitudinal direction of the slit exposure area exposed on the photosensitive surface,
The focus of the exposure apparatus is characterized in that the lens mounting angle is adjusted so that the difference in resolution falls within a predetermined range, and the adjustment result of the lens rotation direction and the lens mounting angle at that time is displayed. How to match.