JPS5829498B2 - Focusing method and device for an electronic copying machine using a short focus lens array as an imaging optical system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a focusing adjustment method and apparatus for a slit exposure type electronic copying apparatus, particularly one using a short focus lens array as an imaging member.

Electronic copying apparatuses that are in practical use today use a normal through lens as an optical system for exposing an image of an original onto a photoreceptor, so the optical path length is extremely short.

Further, in an optical system using a mirror/in-mirror lens, the optical path length becomes significantly longer in the lateral direction.

Therefore, the copying apparatus becomes larger in length and width.

To overcome this drawback, it has been proposed to utilize short focus lens arrays.

In other words, by using a focusing light guide (SELFOC) or a bar lens optical system (these optical systems are referred to as lens arrays in this book) instead of a normal lens, the optical path length can be shortened and the device can be made more compact. I can do it.

In addition, in the conventional optical system described above, focusing requires at least two adjustment factors: movement of the lens in the optical axis direction and tilting of the document table with respect to the optical axis. The adjustment operation is complicated and requires skill.

When a lens array is used, the above-mentioned focusing adjustment becomes simple and easy, and the number of manufacturing steps can be reduced, and at the same time, exposure performance can be improved.

However, this is theoretically possible, and means that can easily and easily make this adjustment are still being explored.

An object of the present invention is to propose the above-mentioned adjustment method and device.

First, an example of a copying apparatus to which a lens array is applied will be briefly described with reference to FIG.

Reference numeral 1 denotes a device main body box, 2 a photosensitive drum that rotates clockwise around a shaft 3, 4 a document table that reciprocates on the top surface of the machine box 1, and 5
The document tray is a glass plate, L is a lens array, T is a primary charger that uniformly charges the surface of the photosensitive drum, 8 is a corona static eliminator that acts on the image exposure area by the lens array, 9
10 is a document illuminator; 10 is a full-surface exposure lamp that irradiates the entire surface of the exposed drum to form an electrostatic latent image (however, there are copying machines with a latent image forming process that does not require this); 11 is a developer; 12 is transfer paper feed sound 13 is drum 2 for transfer paper P
14 is a fixing section that fixes the toner image on the transfer paper that is guided away from the drum; 15 is a copy ejection tray; and 16 is a nominating section.

The relationship and operation of each part of the configuration described above is the same as that of a known one, so a description thereof will be omitted.

In the conventional device, an ordinary through lens is placed at the position of the lens array L.

Alternatively, a mirror is provided to refract the image beam to the right of the machine box and guide it to an in-mirror lens, and the reflected light is imaged on the right side surface of the photosensitive drum, resulting in a large apparatus as described above.

In the conventional optical system described above, the original image on the drum is an erected inverted image, so it is exposed when the original platen 4 moves leftward from the position shown in FIG. Therefore, exposure is performed when the document table 4 once reaches the left direction setting position and returns to the right direction.

Other than this difference, other functions can be considered to be exactly the same.

The short focal length lens array L is shown in FIGS. 2-4.

Figure 2 shows a single focusing light guide L1, where the light ray 1 passing through the center travels straight, and the light ray I2 incident at an angle shows that the refractive index of the light guide changes continuously parabolically from the center outward. Because of this, it penetrates in a meandering manner.

FIG. 3 shows a single bar lens optical system, which forms images according to the optical theory of ordinary lenses.

Those two L2. L3 are arranged on the same optical axis, between which an image P1 is once formed by the front lens L2, and an erect real image P2 is further formed by the rear lens L3.

A short focal length lens array L is constructed by closely arranging a large number of the above-mentioned unit focusing light guides or bar lenses in parallel, and holding the outside with synthetic resin or other suitable material 6.

In such a short focus array, as shown in FIG. 5, for the entire length t, there are t1. =The position of t2 is the object PO
and the position of the imaging plane P2.

Therefore, if the optical axis of the lens array L is placed on the line If the distances t1 and t2 between the exposure surface PO and the photosensitive surface P2t are not equal as described above, out-of-focus will occur.

To this end, it is common sense to fix the photosensitive drum 2 and the short focus lens array L due to the configuration of the apparatus and to adjust the exposure surface PO, that is, the document table 4 up and down, but the structure and operation are complicated and troublesome. It is difficult to expect high precision adjustment.

The present invention relates to the above-mentioned adjustment method and apparatus, in which the bisecting point p of the short focus lens array L in the optical axis direction can be moved in the optical axis XX direction with respect to the support in the machine box.

Also, the intersection point q of the exposure surface PO (original platen 4) with its optical axis
It is configured to be movable in the optical axis direction.

Both of the above are configured to move in the same direction at the same time, and the amount of movement is always 1:
The ratio is 2.

Next, we will explain its principle.

Axis center 3 of the photosensitive drum (temporary axis on the optical axis
Let the distances between them be b, c, and a, respectively.

t in Figure 6. The relationship 11=t2 is the same as in FIG.

By moving the bisecting point p and the intersection q in the optical axis direction, t 1 =
In order to adjust and focus so that t 2, b
= a + Aθ, c = a −1−B
It is sufficient to satisfy θ.

A and B are shift coefficients proportional to the rotation angle θ of the adjustment mechanism cam, which will be described later, and are determined by the focal length, focal depth, etc. of the short focus lens array L.

Furthermore, since the trisection point p of the short focal length lens array L is located at the position t/2, in order to provide the condition of tA=t2, c - b = b - a.

Therefore, the relationship 2A=B is obtained from the above three equations, and the above equation 0 is b = a + Aθ, c = a + 2
It becomes Aθ.

Therefore, by setting the amount of movement of the trisection point p and the intersection q with respect to the photoreceptor surface P2 (movement # with respect to the radius a) to be Aθ:2Aθ=1=2, a good focus can be obtained that always maintains the relationship t1=t2. A match is obtained.

When the upper surface of the glass 5 on the document table 4 and point q are separated by e as shown in FIG. 7, C=a+2Aθ-e.

The adjustment mechanism will be specifically illustrated below.

In FIG. 7, 22 is a cam plate that can be rotated about the shaft 3 of the photosensitive drum 2, and includes a cam follower 20 provided at the trisecting point p of the short focus lens array L, and a cam follower 21 for adjusting the document table. cams 23 and 24 are provided on the upper part of the cam plate 22.

The cam 23°24 is the b=a+Aθ, c=a−1
-2Aθ-e.

An adjustment degree scale 25 is provided at the lower end of the cam plate 22, and the fixed index 2
Instruct with 6.

The above-mentioned mechanisms 20 to 24 are provided on both sides of the lens array L and document table 4 to uniformly adjust them.

In FIGS. 8 and 9, the photosensitive drum 2 is supported in a cantilevered manner on the left side (not shown).

27 is a plate fixed to the side plate of the machine case 1 or the frame inside the machine case, and the cam follower 20 passes through this plate 27 to connect the cam 23.
lead to.

28 is a photosensitive drum mounting hole provided in the plate 27, 29 is a plate that closes the hole, 30 is a frame of the document table 4, 31 is a rail provided on the frame 30, 32 is a frame of a glass plate, and 33 is a plate that covers the hole. This is a slider provided on the lower surface of the frame 32.

When adjusting the focus, the document frame 30 is tilted about a fulcrum 36 by loosening the set screw 35 shown in FIG.

In Figure 9.10, 37 is the short focus lens array holding frame 6.
Loosen the mounting plate 38 provided integrally with the lens when adjusting the focus, and tighten it after adjustment.
7 shows the screws for fixing.

In this figure, the cam follower 20 is laterally shifted by d from the optical axis XX line, but the operation is the same.

Note that between the setscrews 35 and 38 and the plate 27, and between the cam follower 20 and the plate 27, there is a document frame 4 and a short focus lens array L.
Elongated holes 39 to 41 for vertical movement are provided as shown in FIGS. 9 and 10.

Preferably, a bifurcated guide roller or pin 41 is provided to maintain vertical motion.

The above focusing adjustment is performed as follows.

A pseudo drum having a pattern chart with a light source as an adjustment tool is attached to the shaft 3 in place of the photosensitive drum.

Gradually turn the cam plate 22 while observing the chart image projected onto the glass plate 5 through the short focal length lens array L using a magnifying observation device such as a magnifying glass. Fix it.

In this way, the focusing adjustment of the short focal length lens array can be easily and reasonably accurately carried out, and there is an extremely excellent effect in that the number of manufacturing steps can be shortened and the copying accuracy can be improved.

11 to 15 show an embodiment of the device mechanism for the plate 27 of the short focus lens array L.

43 is two surfaces 43A parallel to the optical axis XX of the lens array L.
.

44 is a cover that presses and holds the lens array L against the surface 43A through a spring 45; 44A and 43C are mutually engaging pawls and recesses of the cover 44 and the support 43; FIG. As shown in the figure, the claws 44A are located at the ends of the upper and lower light input/output surfaces of the lens array L that are outside the use surface.

46 is a lens array support frame located outside the plate 27;
Reference numeral 7.48 denotes rollers or pins provided at the upper and lower parts of the support frame 46. The upper roller 47 comes into contact with the upper end of the lens array L, and the lower roller 48 has its upper surface aligned with the extension line Y-- It is received in the receiving recess 43D of the support body 43 so as to be located on Y.

20A is a cam follower attached to the support frame 43 at the center position of the line connecting the centers of the upper and lower rollers 47 and 48, and the pin 4 of the support frame 46 is attached so as to come into contact with the support plane 43B.
A spring 50 is provided between 9 and the plate 27.

51.52 is the optical axis X passing through the axis of the cam follower 2OA
- The upper and lower receiving portions 43E of the support body 43 are linear guide rollers or pins located above and below on the line XA-XA parallel to X.
It is supported when inserted.

27A is a vertical length provided on the plate 27 corresponding to the roller 51; 27B and 27C are slots for inserting the upper and lower pressing rollers 47 and 48; and 27D is a lens array entrance/exit hole.

When the support frame 46 is pushed or pulled in the clockwise direction against the spring 50, the cam follower 2OA is perpendicular to the contact point with the cam follower 2OA [n43B], and the lower tube is fulcrumed at the point of contact between the lower surface of the roller 48 and the receiving recess 43D. Then, the support frame 43 is slightly shifted upward and raised, and the upper pressing roller 47 is separated from the upper surface of the lens array L as shown by the dotted line in FIG.

Therefore, the lens array L can be attached and detached together with the cover 44.

Since the cam follower 2OA is not attached to the holder 6 as shown in FIG. 10, but attached to the support frame 46, there is no need to consider variations in attachment error with respect to the Mikasa equinox point p of the lens array L, and optical adjustment is easy. Improve accuracy.

After the adjustment is completed, the support frame 46 is fixed by tightening the screw 53 into the screw hole of the lower guide roller 52 and pressing its head against the edge of the elongated hole 27A as shown in FIG. 15.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional front view diagrammatically showing an example of an electronic copying device, FIGS. 2 to 4 are schematic diagrams of a short focal length lens array, and FIG.
The figure is an explanatory diagram of the relationship between the object and the image, Figure 6 is an explanatory diagram of the principle of the present invention, Figure 7 is a front view of the main parts of the focusing mechanism of the present invention, Figure 8 is a side view thereof, and Figure 9. is its front view, Figure 10 is an exploded view of the mounting part of the short focus lens array, and Figures 11 to 15 are
The figures are a partial front view and a plan view showing a modified example of a short focus lens attachment mechanism. L is the short focus lens array, p is the Mikasa equinox, P2 is the photoreceptor surface, and PO is the original exposure surface.

Claims (1)

[Claims] 1. In a focusing method for an electronic copying machine using a short focus lens array as an imaging optical system, the short focus lens array is moved in the direction of its optical axis, and the document exposure box and the optical axis are The intersection position with the short focus lens array is also moved in the same direction as the short focus lens array, and at this time, the amount of movement of the trisecting point of the length in the optical axis direction of the short focus lens array with respect to the photoreceptor surface, and the movement of the above intersection position with respect to the photoreceptor surface A focusing method for an electronic copying machine using a short focus lens array as an imaging optical system, characterized in that focusing is performed by moving both of the above lenses so that the ratio between the two lenses is 1:2. 2. In a focusing device for an electronic copying machine that uses a short focus lens array as an imaging optical system, the first support means supports the short focus lens array so as to be adjustable and movable in the optical axis direction, and the document support means is arranged along the optical axis. a second support means that is adjustable and movable in a direction; a first cam follower that rotates integrally with the short focus lens array; a second cam follower that rotates integrally with the document support means; and the first cam follower engages with each other. a first cam surface that engages with the second cam follower, and a second cam surface that engages with the second cam follower, and moves the short focus lens array and document support means in the same direction at the same time with respect to the optical axis direction; At this time, the amount of movement of the trisecting point of the length of the short focus lens array in the optical axis direction relative to the photoreceptor sieve, and the amount of movement of the intersection position of the original exposure surface on the document support means and the optical axis relative to the photoreceptor surface are determined. A focal point of an electronic copying machine having a short focus lens array as an imaging optical system, comprising: a cam that moves so that the ratio is 1:2; and focusing is performed by moving the cam member. Matching device. 3. The focusing device according to claim 2, wherein the cam has a pivot point on an extension of the optical axis of the short focus lens array. 4. The focusing device according to claim 3, wherein the rotational fulcrum is on the rotation axis of the drum-shaped photoreceptor. 5. The focusing device according to any one of claims 2 to 4, wherein the second support means supports the document support means so as to be tiltable about a fulcrum.