JP3382085B2 - Exposure equipment focusing method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a method for focusing an exposure apparatus provided in an image forming apparatus such as an electrostatographic copying machine or a facsimile. 2. Description of the Related Art As an exposure apparatus for an image forming apparatus, a lens whose mounting angle can be changed about a vertical axis is moved in the optical axis direction to slit-expose a document image on a photosensitive surface at different magnifications. Some have a so-called variable magnification 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 resolution around the vertical axis is adjusted so that the difference between the resolutions falls within a predetermined range. By changing the mounting angle of the lens (the direction of the center of the lens), it is possible to perform so-called focusing. In reality, an original image is exposed on a photosensitive surface, a latent image on the photosensitive surface is developed to be visualized, 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 result of this resolution detection, and again execute exposure, development, and transfer / fixing to confirm the completion of focusing. Therefore, an operation of visually detecting a difference in resolution is performed. When the focusing is insufficient, the above operation is repeatedly performed. [0005] However, changing the mounting angle of the lens on the basis of the difference in resolution visually detected and relying on intuition is difficult even for some skilled persons. It is very difficult, and it takes a very long time to achieve a predetermined focus. In addition, while the angle adjustment of the lens is repeated, the result of the adjustment performed earlier is often forgotten, and the adjustment work may be repeated uselessly. To solve the above problems, the present invention provides
An object of the present invention is to make it possible to visually recognize the adjustment results of the rotation direction of the lens and the lens mounting angle at the time of focusing, and to greatly reduce the adjustment time for focusing. That is, according to the present invention, a document image is slit-exposed on a photosensitive surface at different magnifications by moving a lens whose mountable angle can be changed about the vertical axis in the optical axis direction. A focus detection method for an exposure apparatus, wherein sensors for detecting the resolution of an image on both sides in the longitudinal direction of a slit exposure area exposed on a photosensitive surface are provided by a photosensitive driver.
With the exposure unit excluding the ram installed in the main unit,
Set it on the mounting part of the optical drum and then use this sensor
Input the detection result of the resolution
On both sides in the longitudinal direction of the slit exposure area exposed on the surface
The resolution of the images to be compared is compared, and the angle of attachment of the lens is adjusted by turning the vertical axis so that the difference between the resolutions falls within a predetermined range.
Adjusted by changing at Ri, it is characterized in that to display the adjustment result of the rotation direction and the lens mounting angle of the lens at that time. According to such a focusing method, since the result of the focusing adjustment, that is, which direction and how much the angle of the lens has been changed, can be visually controlled, even a person who is unfamiliar with the adjustment. However, focusing can be performed easily in a very short time without unnecessary adjustment. In addition, since the degree of deviation of the lens assembly in a line can be grasped on the basis of the display of the result of the adjustment, the result of the adjustment can be used as a guideline for improving the working form. Since the finish tendency of the molded article can be grasped, the above adjustment result can be used as a basis for the improved design of the mold. DETAILED DESCRIPTION OF THE INVENTION Hereinafter, will be explained based on the embodiment of the present invention with reference to the drawings. FIG. 1 shows an exposure device provided in an image forming apparatus, which projects light reflected from a document surface in the direction of arrow P through a light source 1 and a reflection plate 2 for document exposure and an exposure slit a. The first mirror 3 is provided on the first moving frame 4, and the second and third mirrors 5, 6 for sequentially reflecting the light reflected from the first mirror 3 and projecting in the arrow direction Q are moved in the second direction. Fourth to sixth mirrors 9 to 11 which are provided on the frame 7 and sequentially reflect the light reflected from the third mirror 6 and project on the photosensitive surface of the photosensitive drum 8 are fixedly provided on the apparatus body 12 side. At the same time, the optical lens unit 13 for slit exposure of the original image on the photosensitive surface through the slit a is moved between the third and fourth mirrors 6 and 9 in a reciprocating manner in the optical axis direction so that the projection magnification can be changed. Slit exposure according to the change of the projection magnification And a light amount correction device 14 for correcting the quantity of projected light in the longitudinal direction on both sides of the band. As shown in FIGS. 2 to 4, the light amount correcting device 14 oscillates in a direction in which the light path of the lens 15 is blocked, and corrects the projected light amount on both sides in the longitudinal direction of the slit exposure region. Light correction plates 16, 16, and the light amount correction plates 16, 16 with the movement of the lens in the direction of reducing the projection magnification
And a tilt guide member 17 made of synthetic resin which swings toward the center of the lens. The light amount correction plates 16 and 16 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 over 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 a magnification. It is designed to be reciprocated in the optical axis direction by a dimension corresponding to the magnification. More specifically, the optical lens unit 13
Is mounted on a pair of guide rails 18 and 18 and reciprocally movable in the optical axis direction, and is rotatable and fixed about a vertical axis 22 for positioning provided upright on the lens support 21. A lens center adjustment table 24 fixed by the means 23; and a lens frame 25 including the lens 15 and mounted and fixed to the lens center adjustment table 24 by a set screw b.
As shown in FIG. 5, one end side of the lens center adjustment table 24 (the third mirror 6 side in the illustrated example, but may be the fourth mirror 9 side) is downward. The pair of light amount correction plates 16 and 16 are provided on the bent plate portion 24a. The pair of light amount correction plates 16 and 16 are respectively pivotally mounted on the center side of the bent plate portion 24a via the support shaft 26 in the optical axis direction, and a guide 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 for holding the light quantity correction plate 16 around the guide groove c with the bending plate portion 24a. The screws 26 are fixed to the support shaft 26 and the guide pins 27, respectively. The lower end of the free end side of the light amount correction plate 16 is bent in the horizontal direction, and the bent plate portion 16a is mounted on the inclined guide member 17. According to the above configuration, based on the setting information of the magnification, as the optical lens unit 13 moves in the optical axis direction by the dimension corresponding to the magnification, the fixed pivot by the support shaft 26 is formed. 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 projection magnification reduction direction, the light amount correction plates 16 and 1 are moved.
6 swings closer to the center of the lens and moves the optical lens unit 13 in the direction of enlargement of the projection magnification, the light amount correction plates 16, 16 swing away from the center of the lens to respond to a change in the projection magnification. By correcting the projection light amount on both sides in the longitudinal direction of the slit exposure region, the distribution of the light amount in the longitudinal direction of the slit exposure region is equalized. The light quantity compensating device 15 is composed of two light quantity compensating plates 16 and 16,
16 are supported at two points, and one of the supporting points is a fixed pivot point by the support shaft 26, so that the optical lens unit 1
Although the light amount correction plates 16 and 16 are swung around the fixed pivot point with the movement of 3, the light amount correction plates 16 and 16 can be changed to, for example, a structure in which one light amount correction plate is moved up and down by an inclined guide member. When the mounting angle of the lens 15 is changed to focus on the portions corresponding to both sides in the longitudinal direction of the slit exposure area, the fixing of the lens center adjusting table 24 by the fixing means 23 is released. Lens frame 25
Is mounted and fixed, and the attitude of the lens center adjustment table 24 integrally provided with the light amount correction plates 16 and 16 is changed about the vertical axis 22. As a result, as is apparent from FIG. , 16 and the lens 15 can be adjusted without changing the light amount correction on both sides in the longitudinal direction of the slit exposure area. FIGS. 7 and 8 show an example of an automatic focusing apparatus. This apparatus includes, for example, a CCD sensor 29 for detecting the resolution of an image on both sides in the longitudinal direction of a slit exposure area exposed on a photosensitive surface, a computer 30 for inputting a resolution detection result and comparing resolutions, Lens center adjustment table 2 based on the command
4 comprises a driving means 31 for rotating the axis 4 about the longitudinal axis 22. The entire apparatus is configured to be handled as a jig unit. The sensor 29 is set on the mounting portion of the photosensitive drum 8 in a state where the exposing device except the photosensitive drum 8 is incorporated in the apparatus main body 12, and the computer 30 detects the difference in the resolution comparison result. On the basis thereof, the lens center adjustment base 2 is adjusted so that the difference in resolution falls within a predetermined range.
A command to change the direction of the lens 15 and the angle of the lens 15 is output to the driving unit 31. The driving means 31 has an operation shaft 32 which can be inserted into and removed from a pin hole e formed in the lens center adjusting stand 24, and the driving means 31 itself reciprocates in the optical axis direction by, for example, a stepping motor. It is configured to be possible. According to the above arrangement, the mounting angle of the lens 15 is automatically changed on the basis of the result of the resolution comparison without forming an original image on the recording paper, so that both sides in the longitudinal direction of the slit exposure area are formed. Is automatically performed, and the monitor 33 of the computer 30 displays the result of the automatic focus adjustment, that is, which direction and how much the angle of the lens 15 has been changed. Is done. Of course, the display results can be hard-copied, or the adjustment results stored in memory can be printed out. The mounting angle of the lens center adjustment table 24 may be adjusted artificially. Alternatively, for example, a dial gauge may be brought into contact with the lens center adjustment table 24,
The adjustment result may be displayed in an analog manner. In the above embodiment, the lens receiving base 2
A vertical axis 22 is erected on the upper surface of the lens 1, and the lens center adjustment table 24 is provided so as to be rotatable and fixable around the vertical axis 22. The lens receiving base 21 may be provided with an insertion hole of the longitudinal axis 22, and the lens center adjusting base 24 may be provided so as to be rotatable and fixed with respect to the lens receiving base 21. The present invention is embodied in the form described above, and compares the resolutions of the images on both sides in the longitudinal direction of the slit exposure area exposed on the photosensitive surface, and determines the difference between the resolutions. In the focusing method of adjusting the mounting angle of the lens so that it is within the predetermined range, the adjustment result of the rotation direction of the lens and the lens mounting angle at the time of focusing is displayed, and the adjustment of the focusing is performed. The result, that is, which direction and how much the angle of the lens has been changed, can be managed visually, so even if you are unfamiliar with the adjustment, you can use the result of the focus adjustment. Thus, the focus can be easily adjusted in a very short time without unnecessary adjustment of the lens mounting angle.

BRIEF DESCRIPTION OF THE 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 the optical lens unit and the light amount correction device. FIG. 4 is a detailed front view of the light amount 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 view showing the configuration of an automatic focusing apparatus. FIG. 8 is an explanatory diagram of automatic focusing. [Description of References] 15 ... Lens, 22 ... Vertical axis.

Claims (1)

(57) [Claims 1] Exposure in which a lens whose mountable angle can be changed about the vertical axis is moved in the optical axis direction so that a document image is slit-exposed on a photosensitive surface at different magnifications. A method of focusing an apparatus, wherein a resolution of an image on both sides in a longitudinal direction of a slit exposure area exposed on a photosensitive surface is detected.
Assemble the sensor with the exposure unit excluding the photosensitive drum
After setting it in the photosensitive drum mounting part,
The resolution detection result by this sensor is
The slit exposure area exposed on the photosensitive surface
The resolutions of the images on both sides in the longitudinal direction are compared, and the angle of rotation of the lens at that time is adjusted by changing the mounting angle of the lens around the vertical axis so that the difference in the resolution falls within a predetermined range. A method of focusing on an exposure apparatus, wherein a result of adjustment between the lens and the lens mounting angle is displayed.