JPS5988726A - Optically scanning type exposure device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of black/white streaks on a copied picture, by constituting the titled device in such a way that the lengthwise direction of the clearance section between transparent electrode groups installed in a matrix form does not coincide with the scanning direction but crosses the scanning direction at a prescribed angle. CONSTITUTION:When a transparent slit pattern SP indicated by the non-hatched parts is formed as shown in the obliquely viewed diagram, only one electrode is isolated out of transparent electrodes 30-1-30-10 consisting a transparent electrode group 30 and the isolated electrode is moved from the 30-1 to 30-10. At the same time, correspondingly to the isolated electrode, transparent electrodes 31-1-31-11 consisting a transparent electrode group 31 corresponding to a part forming a slit pattern SP are synchronously isolated. When, for instance, the transparent electrode 30-5 is isolated, the transparent electrodes 31-6, 31-7, and 31-8 are simultaneously isolated. When this operation is made, a part of the slit pattern SP is formed. Therefore, by successively performing this operation to the transparent electrodes 30-1-30-10 and repeating the successive operations to the electrodes, a normal slit pattern SP is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention projects a stationary original image using a moving optical system,
The present invention relates to an optical scanning exposure apparatus that exposes the projected image to a moving photoreceptor through a slit.

Conventionally, in electrophotographic copying machines, the so-called exposure method in which an image of an original is projected onto a photoreceptor is: /) A static exposure method in which both the original and the photoreceptor are held still, and the optical system is also kept stationary for exposure. There is a full-surface exposure method and a scanning exposure (slit exposure) method in which any one of the manuscript, photoreceptor, or optical system is moved to expose the image. The latter includes an optical scanning exposure method in which an optical system is moved, and an original scanning exposure method in which an original and a photoreceptor are moved.

A problem with optical scanning exposure type copying machines is that it is not possible to obtain a uniform illuminance distribution over the exposure area on the photoreceptor due to the moving position of the optical system and the characteristics of the lens itself. There was a point.

Fig. 7 is a schematic diagram when a moving lens type optical system is used, and D in the figure is a sheet-like original, with image A on the lower left side of the figure and image B on the lower center side. , has an image C on the lower right end surface. Reference numeral L denotes a lens, which is disposed below the document tray and is movable from position 11 at the left end in the figure, through position 12 at the center, and to position l at the right end. S is a slit means for exposure, which is fixed below the lens L. Reference numeral E denotes a photosensitive drum, which is disposed below the slit means S.

When the lens L is moved, at position l, image A is projected onto point B on photosensitive drum E by slit means S, image B is projected at position 12, and image C is projected at position A at position A. They are each projected onto point C, and one electrostatic layer image corresponding to images A, B, and C of the document is formed on photosensitive drum E1-.

In this way, the light i4j f
rotates by a certain angle from the start of scanning 7-1 to the end of scanning T13, and the optical images A, B, C of each part of the document D-1-, on the photosensitive drum E, are imaged in different areas a, b. , I decided to give my hat to C, and as a result, I felt like) 1r drama! - Unevenness in illuminance will occur in the exposure area a-C in E. Not only the displacement of the scanning position of the optical system, but also the effect of the 0087 power law of the lens L causes illuminance unevenness on the photosensitive drum El.

In order to compensate for the above-mentioned illuminance unevenness, conventional methods have used optical filters or rotated the entire slit as a unit while moving the exposure slit. This method has the disadvantage of a large loss of light quantity, and the latter method has the disadvantage of a complicated structure. Therefore, in order to eliminate the above-mentioned drawbacks, we used a material (" whose light transmittance changes depending on the conditions such as liquid crystal and electrochromy 4A) in the exposure control section, and this material (") in the form of a matrix. divided into
I want to control whether each moon is transparent or not.
An exposure device has been proposed that controls the exposure by forming a slit-like pattern by combining these elements.However, at the boundaries of each element A divided into a matrix, Is it possible to let light pass through 11 Ti?
The drawback is that the light always passes through the camera, causing thin black or white streaks to appear on the image, reducing the image quality.
Self-′] Puko.

The present invention was proposed in order to solve the above-mentioned drawbacks, and it is an object of the present invention to provide an exposure device that prevents black or white streaks from occurring in a copied image and improves the image quality of the copied image. With the goal.

Embodiments of the present invention will be described based on the accompanying drawings.

FIG. 2 schematically shows a copying machine that performs exposure using an optical scanning method. / is a photosensitive drum that rotates counterclockwise at a circumferential speed of V, numeral is a microfilm that is an original, 3 is a lamp that illuminates the microfilm, gu is a condensing lens, S
1 is a projection lens, B is an integrated mirror consisting of orthogonal reflecting mirrors 71g, and 3 is a slit means for exposure disposed between the projection lens S and the photosensitive drum.

The photosensitive drum consists of a three-layered photosensitive member consisting of a conductive layer, a photoconductive layer, and a transparent insulating layer stacked in this order, and has an insulating layer on its surface. This photosensitive drum is uniformly charged with a secondary charger /S, and then charged with an AC or -secondary charger with a polarity opposite to that of the charge remover/C with a microfilm. While projecting the image light of the second phase, the charge of the second phase 4 is removed, and then the lamp /7 is used to uniformly expose the image, thereby creating an electrostatic latent image in accordance with the projected image pattern on the photosensitive drum. The electrostatic latent image on the photosensitive drum is formed by the imaging device/g.
The transfer paper 2 is developed by the transfer device/9.
Transferred to 0.

Here, when the right-angled mirror unit A is at the solid line position in Figure a, the image a at the right end of the microfilm λ passes through the optical path 2 and is enlarged to the opening [] of the static eliminator/B. is projected as
When the right-angled mirror is located at the chain line position in Figure 2, the image at the left end of the microfilm passes through the optical path 2 and is enlarged and projected onto the static eliminator/open I' band. That will happen.

In this case, by setting the moving speed of the perpendicular mirror unit to 2 of the circumference V of the photosensitive drum, the speed of the projected image of the photosensitive drum is The projected image coincides with the circumferential velocity V, and the projected image is in an interval with the photosensitive drum.

From the above explanation, the relationship between the circumferential speed V of the photosensitive drum / and the moving speed V/2 of the perpendicular mirror body B is constant regardless of the projection magnification on the left side of the lens, and changing the lens magnification is Assuming the speed of Mira is constant, you can do it freely.

FIG. 3 is a cutaway sectional view showing an embodiment of the slit means/3 according to the present invention. 27.2g in the figure is a pair of glass plates, which are spaced apart in parallel. , 29
is a liquid crystal, placed between a pair of glasses, 222g.

Note that 32 is a spacer that separates the pair of glasses 27.2g and seals the liquid crystal 29 between the glasses. 30
．． 37 is a band-shaped transparent electrode group, and as shown in FIG. 9, the transparent electrode group 30 is inclined at a certain angle with respect to the scanning direction F, and the transparent electrodes J and 3/ are arranged in a direction perpendicular to the scanning direction. Be it. The transparent ratio group 30 is a transparent electrode, ")0-7°30-
．． 2-30-70. Transparent electrode group 3/ is transparent electrode 3/-
7, 3/-, 2 to 3/-// (11), but it goes without saying that the number of transparent electrodes is not limited to p- and K. The liquid crystal operating voltage V volts at which the liquid crystal becomes opaque at /, or -
When V volts are applied, the transparent electrode R”Y3O,3/VC
A matrix pattern is formed. In this matrix pattern, the part of the liquid crystal part to which either volt or -V volt is applied becomes opaque due to the electric field generated by the applied voltage, and the part of the liquid crystal part to which no voltage is applied, that is, the intersection of the electrodes to which no voltage is applied. Only the parts corresponding to are transparent. 1- Therefore, the irradiated light is blocked when the voltage is applied to the part at °C, and the light is transmitted to the part to which no voltage is applied.

In this case, it would be better to mechanically shield it with a shutter, etc.
In the case of the projected light from a negative film of microphone [,7 film λ, a general negative film transmission light meter measures about 1/10 of the gold likelihood given to the film surface, and this is about 1/10 of the gold likelihood given to the film surface. Since the light is scattered and becomes uniform as a whole, the light beam that reaches 2g and passes through the glass on the bottom surface is even smaller, and considering the sensitivity of the photoreceptor used in this example, it does not pose any problem for the image forming technician. .

Next, the case of forming a transparent slit pattern SP represented by a non-hatched area as shown in Figures V and G will be described. Transparent +; vi 3o constituting the transparent electrode group 30
-/~30-10, only one pole is cut off, and the transparent electrode to be cut off is moved from 30-/ to 30-10. Transparent electrodes 3/-/ to 3/-// corresponding to the transparent electrodes that are blocked together and forming the transparent electrode group 3/ corresponding to the portion forming the slit pattern sp.
synchronize and shut off. For example, when transparent electrode 30-3- is blocked, transparent electrode 37-B is simultaneously blocked.

3/-7, 37-g is cut off. This operation (7-J,
A part of the slit pattern SP is formed. By repeating this operation sequentially for the transparent electrodes 30-7 to 30-10, a constant l;c' slit pattern SP is formed. This slit pattern SP is created by appropriately selecting the transparent electrodes 3/-/ to 3/-// constituting the transparent electrode group 3/ and applying a voltage to create a slit I/pattern SP in any shape at any location. can be formed. That is, by forming slit patterns of appropriate shapes at positions corresponding to the projected images a and bK, it is possible to prevent unevenness in illuminance on the surface of the photosensitive drum. Note that the transparent electrodes 30-/-30-10 and 3/-
The gap OP between /~3/-// is always transparent and uncontrolled. Normally, light should be blocked except for the transparent portion forming the slit pattern sp, but these transparent electrodes 30-/~30-10 and 3/-/~
Light always passes through the gap OP of 3/-//. This gap OP is the transparent electrode 30-/~30-10 and 3
Although the ratio of the area occupied by /-/ to 3/-// is small, if the longitudinal direction of the gap OP coincides with the scanning direction F (・), the light passes through the gap OP. During the copying process to obtain a positive original from an original, black streaks appear on the image due to continuous exposure to light during exposure.

In the copying process to obtain a positive image from a positive original, white lines and A (conversely appear. Also, this gap OP is opaque1
In this case, contrary to the above, it will appear as white streaks in the copying process to obtain a positive image from the original.
In the copying process to obtain a positive image from a positive original, black streaks appear. However, as in this embodiment, the gap OP
When the transparent electrode group 30 is arranged at a required angle to the scanning direction F so that the longitudinal direction does not coincide with the scanning direction F, the light transmitted through the gap OP is uniformized and becomes so strong that it appears as black or white streaks. The amount of light is not irradiated, and the appearance of black or white streaks on the image is prevented, thereby preventing deterioration in image quality.

Now, assuming that the width a of the slit is constant, then θ-s j-n-1 plate P-, and conversely, when the gap a OP is transparent, the part other than the slit Is it okay to make the amount of light transmitted through the container d uniform? r・, θ-5in'-
”-, but 04・Z-a so that n-ρ is m
It would be preferable if a.

Here, θ is the angle between the scanning direction and the transparent electrode group 30, P is the pitch of the gap OP, l is the width of the exposure device, and n1m is a natural number 7. ．． 2.3...

As described in -4- above, the present invention is capable of opening up black or white streaks on an image caused by gaps between transparent electrode groups, and forming a slit pattern in any position and shape without deteriorating image quality. However, it is possible to make the illuminance of the photosensitive drum surface uniform.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between the exposure slit and the irradiation light flux, FIG. A partial sectional view, FIG. 7 is a perspective view, and the second figure is a transparent electrode I! FIG. 2 is an explanatory diagram showing the inclination angle of λ. /...Photosensitive drum. S...Projection lens. 7, g...Reflector. /3...Slit means which is an exposure control section. 27,. 2g...Glass. , 29...LCD. 30.3/...Transparent electrode group. 30-/~30-10.3/-/~3/-//...
・Transparent electrode. 32...Spacer. OP...Gap part. F...Scanning direction. Figure 1 'Lv 1! :I Figure 2 Figure 3 Figure F Figure 4 (A) OPIf Hand Mystery 1st Hour 5 Figure 181-

Claims (1)

[Claims] It has a transparent electrode group forming a turn and a means for driving and controlling the transparent electrode group, and the longitudinal direction of the gap between the transparent electrode groups arranged in a seven-trick shape does not coincide with the correct or incorrect direction as required. An optical scanning exposure device characterized by being configured to form an angle.