JPS6279438A - Image projecting device - Google Patents

Abstract

PURPOSE:To facilitate operation and to rationalize image density by adjusting automatically the illumination area of a lighting means according to the magnification of a projection lens. CONSTITUTION:When the specific projection lens 10 is mounted on a lens holder 41, a CPU 45 refers to a table with on-off signals from contacts 42-44 and outputs pulses whose number corresponds to the power of the lens 10 to a pulse motor 47 through a driver 46. Then, the motor 47 rotates by specific times to move a field lens to a specific position and the illumination area is adjusted by the movement of the field lens to a proper area agreeing with the image frame reduction rate of a microfilm which is the magnification of the lens 10. Consequently, the operation is facilitated and a print with invariably proper density is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image projection device such as a microfilm reader printer.

(Prior art) There are various reduction ratios for photographing image frames on microfilm.
There are many projection lenses available that match each reduction ratio. Accordingly, in the microfilm reader printer, these projection lenses are detachable or switchable, and a projection lens corresponding to the reduction ratio of the microfilm can be used. At that time, the size of the image frame on the microfilm differs depending on the reduction ratio, so when replacing the projection lens, adjust the illumination area by moving the field lens of the illumination system to ensure the appropriate brightness of the projected image. It is designed to read and print projected images.

(Problems to be Solved by the Invention) However, in the case of such conventional technology, the field lens, etc. must be moved every time the projection lens is replaced or switched, which makes the operation complicated. However, there is a problem in that there are cases where the user forgets to perform an operation and is unable to obtain a print with an appropriate density.

Therefore, the present invention has been made to solve the problems of the prior art described above, and its purpose is to automatically adjust the illumination area when the magnification of the projection lens is changed. It is an object of the present invention to provide an image projection device that is easy to operate and can always produce prints with appropriate density.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an image projection device that illuminates an information recording medium with an illumination means and projects an image of the information recording medium through a projection lens. The apparatus is configured to include a detection means for detecting the magnification of the projection lens, and an adjustment means for adjusting the illumination area of the illumination means according to the magnification detected by the detection means.

(Example) The present invention will be explained below based on the illustrated example. Fourth
In the figure, l indicates a reader printer, and this reader printer l generally forms an image frame of a microfilm F as an information recording medium selectively on a screen z or on a photoreceptor 3. It consists of an optical device 4 for forming an image, a driving device (not shown) for driving the microfilm F, and a copying device 6 as an image recording device for obtaining a copy of a desired image.

The optical device 4 includes a film illumination light source 7, and the light rays from the film illumination light source 7 are irradiated onto the microfilm F via a condenser lens 8 and a field lens 9, and transmitted through the microfilm F. The image light is projected onto the screen 2 via the projection lens lO and the mirror 11.12. Further, the image light of the microfilm F is also projected onto the photosensitive drum 3 of the copying device 6 via the half mirrors 13 and 14 of the scanning unit.

The copying device 6 records an image by an electrophotographic process by operating a print button (not shown), and includes a cartridge 16 in which a developing device 15 and the like surrounding the photosensitive drum 3 are integrally incorporated. ing. 17 is a pre-static elimination exposure lamp.

18 is a transfer charger, 19 is a copy paper force set, 20 is a register roller, 21 and 22 are paper feed rollers, and 23 is a fixing device.

FIG. 1 is a sectional view showing the illumination means. A part of the light rays emitted from the illumination light source 7 is directed to the condenser lens 8 , the other part is reflected by the spherical reflector 24 and enters the condenser lens 8 , passes through the heat insulating filter 25 and is irradiated to the cold mirror 26 . Ru. This cold mirror 26 is of an infrared transmission type, and infrared rays pass straight through.
The other rays are 90° by the cold mirror 26.
The light is reflected upward and condensed by the field lens 9 to illuminate a predetermined area of the image frame of the microfilm F. The image light transmitted through the microfilm F is projected onto the screen 2 or the surface of the photosensitive drum 3 by the projection lens 10.

The field lens 9 is held by a holding member 27. Pins 28 and 29 are protruded from the side surface of this holding member 27, and the pins 28 and 29 are fitted into elongated holes 31 recessed in the side wall of the casing 30 constituting the illumination means. , the holding member 27 can be slid up and down. Further, a rack portion 32 is provided on the other side of the holding member 27, and this rack portion 32 meshes with a gear 33.

This gear 33 is fixed to a drive shaft 34 of a pulse motor (not shown) as a drive means. The holding member 27
A microswitch 35 is disposed below the holding member 27, and when the holding member 27 is lowered to a predetermined position, the microswitch 35 is turned on.

FIG. 2 is a plan view showing a state in which the projection lens is attached to the main body of the reader printer. The projection lens 10 consists of a lens section 36 and a wing section 37, and a projection 38 is provided on the side surface of the wing section 37 at a predetermined position corresponding to the magnification of the projection lens 10.
．． 40 is provided protrudingly. On the other hand, the lens holder 41 is provided with contacts 42, 43, and 44 as means for detecting the magnification of the projection lens 10 by engaging with the projections 38, 40 when the projection lens 10 is attached. Accordingly, the magnification of the projection lens 10 is determined depending on which contact point 42, 43, 44 the protrusion of the projection lens 10 engages with to turn off the projection lens 10.

FIG. 3 is a block diagram showing the control system.

42, 43, and 44 are the above-mentioned contacts, 45 is the CPU, 46 is a driver that drives the pulse motor, 47 is the pulse motor that moves the field lens 9, and 35 is the microswitch.

In the reader printer according to this embodiment with the above configuration, the illumination means is adjusted as follows. That is, when the projection lens 10 is removed from the lens holder 41 in order to replace it with a projection lens IO that matches the reduction ratio of the microfilm F to be projected, the contacts 42, 43, and 44 are all turned ON, and the CPU 45 detects this. Then, the pulse motor 47 is driven via the driver 46 to move the field lens 9 downward. This movement is carried out by the holding member 2.
7 is connected until the microswitch 35 is turned on, and when the microswitch 35 is turned on, the CPU 45
The pulse motor 47 is stopped and the field lens 9 is positioned at the home position shown by the dashed line in FIG.

Next, as shown in FIG. 2, when a predetermined projection lens 10 is attached to the lens holder 41, the CPU 45
．． ON from 43.44.

With the OFF signal, the number of pulses corresponding to the magnification of the projection lens lO is generated by referring to the table shown in Table 1.
It is output to a pulse motor 47 via a driver 46.

The pulse motor 47 rotates a predetermined number of times to move the field lens 9 to a predetermined position, and by moving the field lens 9, the illumination area is adjusted to the magnification of the projection lens 10, that is, the reduction ratio of the image frame of the microfilm F. Adjust to the appropriate area.

Table 1 FIG. 5 is a flowchart showing the above operation.

FIG. 6 shows another embodiment of the image projection apparatus according to the present invention, in which the projection lens is not a fixed focus lens but a zoom lens. That is, the projection magnification of the zoom lens 51 held by the lens holder 50 can be changed by rotating the lever 52 left and right. A protrusion 53 is protruded from the outer periphery of the zoom lens 51, and microswitches 54, 55, and 56 are respectively disposed at positions where the protrusion 53 moves when the zoom lens 51 is rotated to achieve a predetermined magnification. ing. Therefore, when the zoom lens 51 is rotated to change the magnification, the magnification is detected depending on which microswitch 54, 55, or 56 is turned on. The other configurations and functions are the same as those in the previous embodiment, so their explanation will be omitted. 2. In the first embodiment, the magnification is detected based on the presence or absence of the projection lens 10 having three protrusions. However, it goes without saying that the number of protrusions may be four or more.

Further, in the first embodiment, the magnification of the lens may be detected by forming a color code or bar code on the outer periphery of the projection lens 10 and optically detecting this.

Furthermore, in the embodiment described above, the illumination area is adjusted by moving the field lens 9, but the invention is not limited to this, and the condenser lens 8, the illumination light source 7, etc. Of course it's fine.

(Effects of the Invention) The present invention has the above-described structure and operation, and the illumination area of the illumination means can be automatically adjusted according to the magnification of the projection lens, so that it is easy to operate and always maintains an appropriate density. An image is obtained.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of an image projection device according to the present invention, and FIG. 2 is a plan view showing a state in which a projection lens is attached.
FIG. 3 is a block diagram showing a control system, FIG. 4 is a schematic diagram showing a reader printer to which the present invention can be applied, FIG. 5 is a flow chart showing the operation, and FIG. 6 shows another embodiment of the present invention. FIG. Explanation of symbols 7... Light source for illumination 8... Condenser lens 90.・Field lens lO...projection lens 27
...Holding member 32...Rack 33...Gear 38.40...Protrusion 42.43.44
···contact

Claims (1)

[Claims] An image projection device that illuminates an information recording medium by illumination means and projects an image of the information recording medium through a projection lens, comprising a detection means for detecting a magnification of the projection lens, and a magnification detected by the detection means. An image projection apparatus comprising: an adjustment means for adjusting an illumination area of the illumination means accordingly.