JPH0766147B2 - Focusing device for micro film reader printer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a focusing device applied to a microfilm reader printer and capable of fast focusing with a simple structure.

(Technical background of the invention) The original image of a microfilm is enlarged and projected on a screen,
In a reader printer that obtains a hard copy of a projected image by a printer, various autofocus devices that automatically move a projection lens to a focus position have been proposed. This proposed method determines the position of the projection lens so that the contrast of the image read by the CCD line sensor is maximized, for example. However, in this case, it is necessary to detect an image suitable for obtaining the contrast and make it incident on the line sensor, and means for changing the image area incident on the line sensor and a special optical system therefor are required, and the structure is very important. There was a problem that it became complicated.

Further, since the projection lens vibrates when the projection lens is moved or stopped, it is necessary to stop the vibration of the projection lens in order to obtain accurate contrast. For this reason, if the contrast is obtained at many positions of the projection lens, it takes a long time to detect the in-focus position, and conversely, if the in-focus position is predicted by the contrast obtained at a small number of positions, the accuracy decreases. was there.

Further, when the projection lens is at a position extremely far from the in-focus position, the moving direction of the lens in which the contrast increases cannot be determined and the autofocus operation may not be performed.

Also, due to spherical aberration of the projection lens, the same in-focus state cannot be achieved over the entire screen, and for example, if the image is focused in the center of the screen, image blurring around the screen may become excessive. There is also a problem that the focus state does not always match the focus state when autofocusing is performed by using one part of the image.

Particularly in the case of microfilm, the thickness of the film changes, and the image is imprinted on the front or back of the film. Therefore, the focus position of the lens changes depending on the film. But for the same film,
Since the film thickness is constant and the image is printed on one of the front and back sides of the film, the focus position for each frame is almost constant. However, even in such a case, the operation time becomes long if the normal autofocus operation is performed.

(Object of the invention) The present invention has been made in view of the above circumstances, and is a microfilm reader capable of performing focusing with a very simple structure, a high operating speed, and a sufficiently high precision for practical use. It is an object to provide a focusing device for a printer.

(Constitution of the Invention) According to the present invention, a purpose is to manually move the projection lens to a focusing position, a position detecting means for the projection lens, and a plurality of past focusing positions of the projection lens. A storage unit that stores a position based on a storage command signal, and a lens drive that sequentially moves the projection lens based on the focus command signal to a plurality of target positions obtained from a plurality of past in-focus positions stored by the storage unit. And a focusing device of a microfilm reader printer, comprising:

That is, the focus positions of the same projection lens are almost the same for the same type of microfilm, and the number of types of microfilm is not infinite, and it is usually limited to several types. A plurality of in-focus positions are stored and aligned with one of the past in-focus positions. It is possible to move to a different focus position each time the focus command signal is output.
Even if the result of this operation is not the correct focus, place the lens at the closest position and then easily manually move it to the focus position by the manual means, and re-create this new focus position. Can be memorized.

It should be noted that the lens driving means can use the frequency (histogram) of the past focus position stored in the storage means to move the lens in order of high frequency, and the stored histogram stores new data every time the focus is achieved. Read and modify,
So to speak, it is preferable that this storage means has a learning function.

(Embodiment) FIG. 1 is an overall view of an embodiment of the present invention, FIG. 2 is a functional block diagram thereof, and FIG. 3 is an operation flow chart showing an embodiment of the operation.

In FIG. 1, reference numeral 10 is an original microphotograph such as a microfiche or a microroll film.
10 can be transferred on the table 12 by a fish carrier, a roll film holder (both not shown) or the like. Reference numeral 14 denotes an illumination system, which includes a light source 16, a condenser 18, a heatproof filter 20, a reflecting mirror 22 and the like. The light from the light source 16 is reflected by the mirror 22.
Guided under the original picture 10.

In the reader mode, the reflecting mirror 24 is at the position shown by the solid line in FIG. 1, and the projection image transmitted through the original image is the projection lens 26 and the reflecting mirror 2.
It is guided to the transmissive screen 32 via 8, 24 and 30, and an enlarged projection image is formed on this screen 32.

In the printer mode, the reflecting mirror 24 is rotated to the phantom line position in FIG. 1, and the projection image transmitted through the original image 10 is reflected by the reflecting mirror 28,
It is guided to the slit exposure type printer 38 via 34 and 36.
The photosensitive drum 40 of the printer 38 rotates in synchronization with the parallel movement of the reflecting mirrors 28 and 34, and a latent image of a projected image is formed on the drum 40. The toner image formed by the latent image is transferred onto the paper 42, fixed, and ejected onto the paper ejection tray 44.

50 is a CPU, 52 is an input interface, 54 is an output interface, and 56 is a memory as the storage means A. The projection lens 26 includes a CPU 50, a DC motor 58, a driver 6
While being moved by the lens driving means B consisting of 0 etc.,
The lens position a is detected by the rotary encoder 62 as the position detecting means C and is read by the CPU 50 via the input interface 52. Reference numeral 64 is an up / down switch as a manual means D for manually setting the lens 36 to the in-focus position while looking at the screen 32,
By pressing either the up switch 64a or the down switch 64b, the CPU 50 causes the output interface 5
4. The motor 58 is normally or reversely rotated via the driver 60 to move the lens 26 upward or downward.

66 is a memory command manual switch, and based on the memory command signal b output by pressing the switch 66, the CPU 50
The position a of the lens 26 at that time as the in-focus position
Remember.

Reference numeral 68 denotes a print switch, and when pressed, the copy command signal C is output to select the printer mode and the printer is selected.
38 is activated to copy.

Reference numeral 70 denotes a focus command manual switch, which is pressed to output the focus command signal d. The focus position of the lens 26 is stored in the memory 56 together with the frequency as a histogram, and the CPU 50 reads out the focus position having the highest frequency based on the focus command signal d and sets it as the target position.

Next, the operation of this embodiment will be described with reference to FIG. When the power is turned on, the CPU 50 first moves to the origin, which is the reference for position detection of the projection lens 26 in the reader mode, and the position detection means C (encoder 62) starts position detection (step 100). The CPU 50 selects the M mode (manual mode) until the focus command signal d is output by pressing the switch 70 (step 102). In the M mode, the user can appropriately move the projection lens 26 by the up / down switch 64 (step 104), and if the focus position matches the focus position (step 106), the user uses the memory command switch 66 to store the focus position. Remember in 56. As a result, the histogram stored in the memory 56 is modified (step 108).

When the focus command signal d is output by the switch 70, the CPU 50 determines that the F mode (focus mode) is selected (step 102), reads out the most frequently focused position from the memory 56, and reads this out as the first target. As a position, the projection lens 26 is moved to this position (step 110).
When the user looks at the screen 32 and is in focus, the switch 66 outputs the memory command signal b (step 112), and the histogram is corrected so that the frequency of this position is increased by 1 (step 114). If it is not in focus, it is determined again whether the focus command signal d is output (step
116). In the M mode, manual focusing is performed according to the operations of steps 104 to 108, and in the F mode, the focus position with the second highest frequency is read from the memory 56 as the second target position and the projection lens 26 is moved to this position. It is moved (step 118). If the result is in focus (step 120), the histogram is corrected (step 114), and if out of focus, switch between manual operation and moving to another target position.
If it is input at 70 and manual operation in M mode is selected, the operations of steps 104 to 108 are performed (step 12
2) If the F mode is selected, the third frequency position is read from the memory 56 as the third target position and the projection lens is moved to this position.
26 is moved (step 124). If it is in focus (step 126), the histogram is corrected (step 114), and if it is out of focus, the process directly returns to step 102.

In this embodiment, the focus position is read up to the third frequency, but four or more focus positions may be sequentially read as the target position. Further, the target position is not limited to the one read out in order of the frequency by the histogram, and various algorithms are possible, such as reading back the in-focus positions one degree before, two degrees before, and three degrees ago in reverse order.

In this embodiment, the memory command signal b is output by the manual switch 66, but the present invention is not limited to this. For example, in the M mode, the manual means D (switch 64) is stopped for a predetermined time or longer, the printer mode is selected by the switch 68, and the like, and it is determined that the focus is achieved.
The storage command signal b may be output to store the in-focus position.

Similarly, the focus command signal d is not limited to being output by the manual switch 70. Original picture 10
It is also possible to detect the completion of the movement and output the signal d to move the lens 26 to the target position. When the projection lens 26 can be replaced, the completion of replacement may be detected by the sensor 72 (FIG. 1), and the signal d may be output based on the completion of replacement.

The memory 56 of the storage means A is provided for each interchangeable lens or each film holder such as a fish carrier or a film holder, and the type of the interchangeable lens or the film holder is detected to select the memory to be used, or the interchangeable lens or A memory may be arranged on the lens holder side, and each lens or film holder itself may have data for each lens or film holder.

(Effect of the invention) As described above, the present invention is configured to sequentially move the projection lens to a plurality of target positions obtained from a plurality of past focus positions stored in the storage means based on the focus command signal. A line sensor and an optical system for detecting an image are not required, and the configuration is very simple, and the operation is fast. In addition, it can be corrected by manual operation, and since a correct focus position can be stored and a learning function can be provided so that it can be used for subsequent operations, focusing can be performed with sufficiently high accuracy for practical purposes. It will be possible.

Further, there is an effect that the focus position stored in the storage means can be set and changed according to the preference of the operator.

[Brief description of drawings]

FIG. 1 is an overall view of an embodiment of the present invention, FIG. 2 is a functional block diagram thereof, and FIG. 3 is an operation flow chart showing an embodiment of the operation. 10 ... Original image, 24 ... Projection lens, A ... Storage means, B ... Lens driving means, C ... Position detecting means, D ... Manual means, b ... Storage command signal, d ... Focus signal.

Claims (8)

[Claims] 1. A manual means for manually moving a projection lens to a focusing position, a position detecting means for the projection lens, and a plurality of past focusing positions of the projection lens are stored based on a storage command signal. And a lens driving unit that sequentially moves the projection lens to a plurality of target positions obtained from a plurality of past focus positions stored in the storage unit based on a focus command signal. Focusing device for micro film reader printer. 2. The storage means stores a plurality of past focus positions and their frequencies, and the lens drive means sequentially sets a target position from a focus frequency having a high frequency based on the focus command signal. A focusing device for a microfilm reader printer according to claim 1. 3. The storage command signal is output by a storage command manual switch.
A focusing device for a microfilm reader printer according to the above paragraph. 4. The focusing device for a microfilm reader printer according to claim 1, wherein the storage command signal is output when the manual means is stopped for a certain period of time. 5. The focusing device for a microfilm reader printer according to claim 1, wherein the storage command signal is output based on a copy command signal for selecting a printer mode. 6. The focusing device for a microfilm reader printer according to claim 1, wherein the focus command signal is output by a focus command manual switch. 7. The focusing device for a micro film reader printer according to claim 1, wherein the focus command signal is output based on completion of movement of the micro original image. 8. The focusing device for a microfilm reader printer according to claim 1, wherein the focus command signal is output upon completion of replacement of the projection lens.