JPH0223852B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an illuminance distribution pattern adjuster that is disposed in an optical path between an illumination light source and a photoreceptor in a copying machine, for example, and adjusts the illuminance distribution pattern of light.

In general, in copying devices, in order to obtain highly reproducible copied images of originals, it is necessary to make the illuminance distribution of light on the photoreceptor uniform.
In order to achieve this requirement, the illuminance distribution pattern in the length direction of the elongated strip-shaped illumination area on the document table must be changed so that the illuminance at both ends of the illumination area is at the center, as shown in characteristic curve I in Figure 1. It is required that the overall illuminance is large compared to the illuminance of the area and has a wavy shape. For this reason, for example, as shown in FIG. 2, a partially emitting type rod-shaped light bulb B consisting of a plurality of light emitting parts F connected via a non-emitting part N is used as a light source light bulb. It is assumed that the length of the central light emitting part F is larger than the length of the central light emitting part F, so as to obtain an illuminance distribution pattern in which the illuminance at both ends is greater than that at the center. Strictly speaking, each individual item is different, so when these individual items are combined, the illuminance distribution pattern on the document table will be slightly different depending on the device even if they have the same configuration. Even if used, it is extremely difficult to obtain an ideal illuminance distribution pattern on the document table, and the illuminance distribution pattern must be adjusted.

Under these circumstances, for example, as shown in FIG. 3, a plurality of light shielding plates 10 shown in FIG. By arranging them along the length direction and regulating the amount of light transmitted by each by adjusting the penetration depth S into the optical path of each, or by regulating the amount of light transmitted by each of them, or by regulating the amount of light transmitted by each of them, Light bulb B using a light transmission amount distribution regulating member having a light slit
By compensating for the light emitting characteristics in the longitudinal direction, the illuminance distribution pattern in the illumination area on the document table T is made ideal or approximated thereto.

However, in the method of arranging a plurality of light shielding plates 10 in parallel, it is necessary to adjust the penetration depth S of each of the light shielding plates 10, which requires a long time to adjust the illumination distribution pattern. In the case of using a light transmission amount distribution regulating member having a light transmitting slit, the mode of adjustment of the illuminance distribution pattern is uniquely determined by the shape of the slit. In addition to having to prepare a number of lamps, it is tedious to select a suitable one from among them, and in the end, when assembling the device, and furthermore, each time the bar-shaped light bulb is replaced, the illuminance distribution pattern must be adjusted. Such complicated work will have to be carried out.

The present invention has been made based on the above circumstances, and it is possible to easily adjust the illuminance distribution pattern of an elongated strip-shaped illumination area, and therefore, when used in a copying machine, for example, The purpose is to provide an illuminance distribution pattern adjuster that can obtain a uniform illuminance distribution on a photoreceptor.
Its features include a first slit member in which light-transmitting parts and light-blocking parts are formed alternately along the length direction; , a second slit member in which light-transmitting parts and light-blocking parts are alternately formed along the length direction, and the light-transmitting parts and light-blocking parts related to the first slit member are arranged in the length direction. The difference is that the pattern and the arrangement pattern in the length direction of the light-transmitting portion and the light-blocking portion of the second slit member are different from each other.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 5 shows an illuminance distribution pattern adjuster disposed between an illumination light source and a document table in a copying machine. teeth,
A first slit member 1 having one edge formed in a rectangular wave shape and a second slit member 2 having one edge formed in a rectangular wave shape are moved in the length direction so that the rectangular wave shaped edges overlap each other. The second slit member 2 is stacked so as to be freely, for example, slidably, and is provided with a fixing mechanism that prevents the second slit member 2 from sliding with respect to the first slit member 1. The first slit member 1 has a sixth slit member 1.
As shown in FIG. The width l1 of the light shielding part 12 is uniformly set to, for example, 5 mm, and the second slit member 2
As shown in FIG.
2, the width L2 of the light-transmitting part 21 and the width l2 of the light-shielding part 22 in the length direction of the slit member 2.
is uniformly set to, for example, 5.5 mm. and the first
The slit member 1 has a long hole 1 extending in the length direction.
3, and a plurality of small holes 14 are formed at equal intervals in the length direction, and the second slit member 2 is formed with long holes 23 extending in the length direction, and a plurality of small holes 14 are formed in the second slit member 2. The small holes 24 of the first slit member 1 are formed so as to be arranged at equal intervals in the length direction with slightly smaller intervals than the small holes 14 of the first slit member 1. and the long hole 23 of the second slit member 2, and the small hole 14 of the first slit member 1 and the small hole 24 of the second slit member 2 are screwed together. Possibly the first
The slit member 1 and the second slit member 2 can be fixed to each other (in FIG. 5, the small holes 14,
24 are not overlapped and are not yet fixed to each other. ), thus forming a fixing mechanism that prevents the two slit members 1 and 2 from sliding.

In the illuminance distribution pattern adjuster configured as described above, when the screw related to the fixing mechanism is loosened and the second slit member 2 is slid with respect to the first slit member 1, these two slits Width L3 of each transparent region 31 formed by members 1 and 2
The width l3 of each light shielding area 32 changes, for example, the degree of overlapping of the slit members 1 and 2 is changed as shown in FIG. The transparent part 11 located on the leftmost side of the second slit member 2 (the second slit member 2 is indicated by diagonal lines),
When the left edges of 21 are aligned, the transparent area 3
1 and the light shielding area 32, the width L3 of the light transmitting area 31 becomes smaller as it approaches the center, as shown as P7 in FIG. By placing the light source on the front side of the paper in Fig. 7A), the illuminance distribution pattern on the rear side of the adjuster (the back side of the paper in Fig. 7A) is determined by the light transmittance of the central part, as shown as I7 in Fig. 7C. is in a state where it has decreased. Then, as shown in FIG. 8A, the degree of overlapping of the slit members 1 and 2 is as shown in FIG. When displaced, the arrangement pattern of the light-transmitting region 31 and the light-blocking region 32 becomes larger as the width of the light-transmitting region 31 approaches the center, as shown as P8 in FIG. The pattern is in a state where the light transmittance in the central portion is high, as shown as I8 in FIG. 8C. That is, the first
The width L1 of the light-transmitting part 11 and the width l1 of the light-shielding part 12 in the slit member 1 and the second slit member 2
Since the width L2 of the light-transmitting part 21 and the width l2 of the light-shielding part 22 are slightly different, the width L3 of the light-transmitting region 31 formed when the two slit members 1 and 2 are overlapped, in other words, the width L2 of the light-transmitting part 21 and the width l2 of the light-shielding part 22 are Since the area of the region 31 increases sequentially along the length direction and then decreases again, the illuminance distribution pattern formed on the rear side of the adjuster is determined by the width L3 of the transparent region 31. The second slit member 2 becomes undulating in response to the change in size.
When the slit member 1 is slid against the first slit member 1, the undulations move according to the sliding distance while maintaining the waveform. The undulation related to this illuminance distribution pattern is due to the undulation phenomenon that occurs when two waves with slightly different frequencies are superimposed. To explain this phenomenon schematically, one edge of the first slit member 1 Assuming that the shape of is a sine wave y1 expressed by equation (1), and the shape of one edge of the second slit member 2 is a sine wave y2 expressed by equation (2), the composite wave y3 of both is expressed by equation (3). It is expressed as

y1=Acos(ωx) (1) y2=Acos{(ω+δ)x−φ} …(2) y3=2Acos(δ/2x−φ/2) ・cos{(ω+δ/2)x−φ/2} …(3) However, L1+l1=2π/ω L2+l2=2π/ω+δ, and the axis extending in the width direction of the slit member is y
The axis extending in the length direction of the slit member was defined as the x-axis. Note that A is a constant and δ is two sine waves y1, y2
The difference in angular velocity, φ, indicates the magnitude of the phase displacement of the two sine waves y1 and y2.

When the difference between the periods of the above two waves y1 and y2 {(L2+l2)-(L1+l1)} is small, this composite wave y3 becomes a gentle wave due to a beat phenomenon. By overlapping the members 1 and 2, the width L3 of the light-transmitting region 31, that is, the area of the light-transmitting region 31, changes sequentially along the length direction, and the interval between the light-transmitting regions with the largest area (as described above) changes sequentially along the length direction. In the formula, it corresponds to the beat period.)
becomes 4π/δ, and by changing the degree of overlap between the two waves, the phase shifts without changing the waveform.

In the illuminance distribution pattern adjuster according to the above-described embodiment, the light-transmitting regions 31 are arranged in such a manner that the width L3 thereof varies sequentially along the length direction, so that the light-transmitting regions 31 are arranged in the form of a long and narrow strip. By placing it in the optical path, it is possible to obtain a wavy illuminance distribution pattern with gentle undulations in the illumination area, and also to allow the second slit member 2 to slide with respect to the first slit member 1. Therefore, the illuminance distribution pattern can be slightly changed while remaining in a wavy shape, and therefore, for example, as shown in FIG.
The above-mentioned adjuster 100 is disposed between the illumination light source consisting of the reflecting mirror M and the document table T, and the slit members 1 and 2 are moved relative to each other in the length direction to adjust the degree of overlap between the two. Accordingly, it is possible to obtain an ideal state or an illuminance distribution pattern approximating the ideal state in the illumination area on the document table T. In other words, when a rod-shaped light bulb is used as a light source bulb as described above, the illuminance distribution pattern in the illumination area on the document table has a shape in which both ends are higher than the center. In order to approximate the pattern, the valley in the center may be made slightly higher and the peaks at both ends may be made slightly lower, or the valley in the center may be made slightly lower and the peaks at both ends may be made slightly higher. It is necessary to make minute adjustments to the illuminance distribution pattern of the illumination area on the document table, and the adjuster with the above configuration can easily make such minute adjustments to the pattern. This makes it possible to obtain a uniform illuminance distribution on the photoreceptor in a short time. As described above, since the fixing mechanism is provided to prevent the second slit member 2 from sliding with respect to the first slit member 1, the first slit member 1 and the second slit member 2 can be position (in this example, long holes 13, 23 or small hole 1)
4 and 24) can be fixed to each other at the position where they overlap. Moreover, since the spacing between the small holes 14 in the first slit member 1 and the spacing between the small holes 24 in the second slit member 2 are made to be slightly different from each other, the slit members 1 and 2 can be overlapped. By minutely sliding, the small holes 14 and 24 arranged in the length direction of each slit member 1 and 2 will overlap one after another (from the state where the left edges of each slit member 1 and 2 are aligned). When the second slit member 2 is moved to the right, the first slit member 2 is moved from the left side.
The second small holes 14 and 24 overlap, and when moved further to the right, the second small holes 14 and 2 from the left side overlap.
4 overlap, and in this way the small holes 14, 24
The two slit members 1, 2 are successively overlapped), and by slightly changing the positional relationship of the two slit members 1, 2, and inserting screws into the overlapping small holes 14, 24 after adjustment, the two slit members 1, 2 can be securely fixed to each other.

Here, a preferred numerical example will be given in a specific example where the illuminance distribution pattern adjuster having the above-mentioned configuration is placed in the optical path of the illumination light source in a copying machine and is installed between the illumination light source and the document table. The width L1 of the light-transmitting part 11 and the width l1 of the light-shielding part 12 of the first slit member 1 are each 5 mm, and the width L2 of the light-transmitting part 21 and the width l2 of the light-shielding part 22 of the second slit member 2 are 5 mm. are each 5.5 mm, and to give a preferable numerical example in a specific example where it is provided between a projection optical device such as a self-occurring lens and the photoreceptor, the width of the transparent part 11 related to the first slit member 1 is L1 and the width l1 of the light shielding part 12 are each 3 mm, and the width L2 of the light transmitting part 21 related to the second slit member 2 and the width l1 of the light shielding part 2 are 3 mm.
Assume that the width l2 of 2 is 3.1 mm.

Although one embodiment and a specific configuration example of the present invention have been described above, the first slit member 1 and the second slit member
Regarding the slit member 2, (a) instead of forming one edge of the slit member into a rectangular wave shape, it is formed into a triangular wave shape or a sinusoidal wave shape to form a light transmitting part and a light shielding part, (b) a structure in which a light transmitting part and a light blocking part are formed. (c) A configuration in which the width of each light-transmitting part of the slit member is not constant, or a configuration in which the width of each light-shielding part of the slit member is not constant; It is also possible to form a light-transmitting part and a light-blocking part by providing the light-transmitting part 11 and the light-blocking part 12 in the first slit member 1 at intervals. It is necessary that the arrangement pattern along the length of the second slit member 2 and the arrangement pattern of the light-transmitting portion 21 and the light-shielding portion 22 along the length direction of the second slit member 2 are slightly different from each other. When 1 and 2 are overlapped, the area of the light transmitting region 31 in the adjuster changes sequentially along the length direction.

(d) Instead of the first slit member 1 and the second slit member 2 slidingly overlapping each other, the first slit member 1 and the second slit member 2 may be configured to overlap each other so as to be movable through a space.

(e) In the fixing mechanism that prevents movement of the second slit member 2 with respect to the first slit member 1, a locking member that clamps the edge of the second slit member 2 is provided on the first slit member 1. A wide variety of configurations can be used, such as the configuration in which it is provided.

As described above, the present invention includes a first slit member in which light-transmitting parts and light-blocking parts are formed alternately along the length direction, and a first slit member that is movably superimposed on the first slit member in the length direction. In addition, the second slit member includes a second slit member in which light-transmitting parts and light-blocking parts are formed alternately along the length direction, and the light-transmitting part and the light-blocking part related to the first slit member are formed in the length direction. Since the arrangement pattern and the arrangement pattern in the length direction of the light-transmitting parts and the light-blocking parts related to the second slit member are different from each other, the illuminance distribution pattern of the elongated strip-shaped illumination area can be easily adjusted. Therefore, it is possible to provide an illuminance distribution pattern adjuster that can obtain a uniform illuminance distribution on a photoreceptor in a short time when used in a copying machine, for example.

The illuminance distribution pattern adjuster according to the present invention includes:
The present invention is not limited to use in copying machines, and can be used for various purposes, such as being incorporated into the illumination system of facsimile machines.

[Brief explanation of drawings]

Fig. 1 is a characteristic curve diagram showing an example of an ideal illuminance distribution pattern on the document table of a copying machine, Fig. 2 is an explanatory diagram showing an example of a rod-shaped light bulb used in a copying machine, and Fig. 3 is a diagram showing an example of a rod-shaped light bulb used in a copying machine. 4 is a plan view showing the light shielding plate used in FIG. 3, and FIG. 5 is an embodiment of the illuminance distribution pattern adjuster according to the present invention. FIGS. 6A and 6B are plan views showing the first slit member and second slit member in the regulator shown in FIG. An explanatory diagram showing an example of how the first slit member overlaps with the second slit member, an explanatory diagram showing the arrangement pattern of the light-transmitting area and the light-blocking area, and a characteristic curve diagram showing the illuminance distribution pattern, Figures 8A and 8B. Also, Ha is
FIG. 9 is an explanatory diagram showing another example of the overlapping condition of the first slit member and the second slit member, an explanatory diagram showing the arrangement pattern of the light-transmitting area and the light-blocking area, and a characteristic curve diagram showing the illuminance distribution pattern, respectively. FIG. 2 is an explanatory diagram showing an example of a case where the illuminance distribution pattern adjuster according to the present invention is used in a copying apparatus. DESCRIPTION OF SYMBOLS 1...First slit member, 2...Second slit member, 11, 21...Transparent part, 12, 22...
...Light shielding part, 13, 23... Long hole, 14, 24...
Small hole, 31... Light-transmitting area, 32... Light-blocking area, 1
00...Illuminance distribution pattern adjuster, B...Stand-shaped light bulb, M...Reflector, T...Original table.

Claims (1)

[Claims] 1. A first slit member in which light-transmitting parts and light-blocking parts are formed alternately along the length direction, and a first slit member superimposed on the first slit member so as to be movable in the length direction. , a second slit member in which light-transmitting parts and light-blocking parts are alternately formed along the length direction, and the light-transmitting parts and light-blocking parts related to the first slit member are arranged in the length direction. An illuminance distribution pattern adjuster, characterized in that the pattern and the arrangement pattern in the length direction of the light-transmitting parts and the light-blocking parts of the second slit member are different from each other. 2 The first slit member has a width L1 of the transparent part.
and the width l1 of the light shielding portion are each constant, and the second
In the slit member, the width L2 of the transparent part and the width l2 of the light shielding part are constant, and the widths L1 and L2 of the transparent part are constant.
are different from each other or the widths l1 and l2 of the light shielding part
2. The illuminance distribution pattern adjuster according to claim 1, wherein the illuminance distribution pattern is different from each other.