JPS6230413B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a lens position control method, and more specifically to a lens position control method in a variable magnification copying machine. In conventional variable magnification copying machines, the lens is stopped on the assumption that the variable magnification displayed by the variable magnification key is the same as the variable magnification determined by the actual lens position. However, this conventional method has the disadvantage that the actual position of the lens changes depending on the timing at which the variable magnification key is pressed, causing the variable magnification ratio to be incorrect. In particular, if the variable magnification key is pressed just before leaving the operating range of the position detecting element, the lens will stop outside the operating range of the position detecting element due to inertia, so the actual stopping position of the lens will be determined by position detection. This is a wide range that extends beyond the operating range of the element. Therefore,
There was a drawback that the desired magnification could not be obtained accurately, leading to a decrease in image quality. Furthermore, Japanese Patent Laid-Open No. 52-115217 discloses an invention in which a conversion base is provided and the optical system is always stopped at a desired position only when moving from a specific direction. problems occur. An object of the present invention is to prevent the stop position from shifting due to the fact that the operating range of the position detection element has a certain width and the timing at which the magnification is input using a variable magnification key, etc., and to change the stop position to the position detection element. It is an object of the present invention to provide a lens position control method that can be limited to a relatively narrow range within the operating range. The invention will now be described with reference to the accompanying drawings, in which preferred embodiments thereof are shown. FIG. 1 is a schematic diagram of a variable magnification copying machine. In the same figure, 1
is a light source, 2 is a reflecting mirror, 3 is a transparent document table, 4,
5, 7, and 8 are reflecting mirrors, 6 is a lens, 9 is a photosensitive drum, 10 is an electric fan, 11 is a reflector, 12 is a copying machine body having a protrusion 13, and 14 is a shaft mounted on the protrusion 13. , and 15 is a cover that houses the automatic feeding device. A light beam emitted from a light source section consisting of a light source 1 and a reflecting mirror 2 is reflected by an original placed on an original platen 3, reflected by reflecting mirrors 4 and 5, passes through a lens 6, and is further reflected. The light is reflected by the mirrors 7 and 8 and reaches the photosensitive drum 9 for image exposure. A cooling unit composed of an electric fan 10 and a reflector 11 cools an automatic feeding device housed in a cover 15 by blowing air. In addition, cover 1
5 is rotated around a shaft 14, and when in use, the document table 3 is placed on its back, and when not in use, it is raised as shown in the figure. Next, FIG. 2 is a block diagram for explaining the method of the present invention. In the same figure, A,
B and C are position detection elements (Hall ICs) of 1:1, 82% and 71%, respectively, M is a magnet, 6 is the above-mentioned movable lens, and 6' is a threaded drive shaft. FIG. 3 is a diagram similar to FIG. 2 for explaining the movement of the movable lens 6. In the conventional method, if the magnification ratio key of B is pressed when the magnet M reaches position B while the lens 6 is moving from position A to position C, the position switch of B is activated. The lens 6 stops at the dotted line position. Similarly, when the key is pressed when the magnet M reaches position A while moving from position C to position A, the lens stops at the solid line position. Therefore, depending on the timing at which the magnification key is pressed at position B, an error in the magnification ratio may occur from the dotted line position to the solid line position, causing the above-mentioned problem. In order to eliminate the above-mentioned error, the present invention invalidates the input of the magnification using the variable magnification key or the like while the lens 6 is moving between position A and position B, and the magnification setting operation based on the input is disabled. This is to prevent it from happening. In other words, the period from position A to position B mentioned above means within the operating range of the position detection element. Next, FIG. 4 is a flowchart for explaining the method of the present invention. When the magnification key is turned on, the process proceeds to the LENS ON comparator and step 1 is executed. When the lens is turned on, it moves in the direction of the arrow on the Y (abbreviation for YES) terminal and step 2 is executed; when it is not on, it moves in the direction of the arrow on the N (abbreviation for NO) terminal, so step 2 is skipped. . LENS POSITION ON
If position detection is turned on in the comparator, the comparator moves in the direction of the arrow at the Y terminal and skips steps 3 and below; if it is not turned on, it moves in the direction of the arrow at the N terminal and sequentially executes steps 3 and below. Next, the operations of each step are listed. Step 1: Determine whether the lens is on or off. If it is turned on, step 2 is executed; if it is turned off, step 2 is skipped. Step 2: Determine whether the position detection element is on or off. When it is on, it is passing near the position detecting elements (within the operating range), and when it is off, it is passing between the position detecting elements (outside the operating range). (If the lens is turned on and the position detection element is turned on according to the conditions of step 1 and step 2, it is determined that the lens is passing near the position detection element, and steps 3 and below are not executed and the key is disabled.) ) Step 3: Memorize which magnification key was pressed. Step 4: When the pressed key is accepted, the lamp for that key is lit (a lamp is provided for each key). Step 5: The key magnification ratio stored in Step 3 is compared with the data of the position detection element to control lens operation. Step 6: Executed when the magnification ratio of the key and the position detection element (magnification ratio) do not match in step 5.

[Formula] determines whether the key magnification ratio stored in step 3 was 82%. If it is 82%, it will proceed to the Y terminal, and if it is not 82%, it will proceed to the N terminal.

[Formula] determines whether the key magnification ratio stored in step 3 was 71%. If it is 71%, it will proceed to the Y terminal, and if it is not 71%, it will proceed to the N terminal.

[Formula] determines that when the lens is between 71% and 82%, it is in AREA B, and when it is between 82% and 1:1, it is in AREA A. LENS-R (abbreviation for lens return) and LENS-
F (abbreviation for lens forward) is as follows.

[Table] 〓The arrow is here〓
LENS〓R LENS〓F
〓Moving direction of lenses〓
Among the above steps, steps 5 and below are so-called lens control. In summary, according to the present invention, the shift of the stop position of the lens due to the fact that the operating range of the position detection element has a certain width and the timing at which the magnification is input using the variable power key etc. can be prevented, and the stop position can be adjusted. can be limited to a relatively narrow range within the operating range of the position detection element.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a variable magnification copying machine, FIG. 2 is a configuration diagram for explaining the method of the present invention, and FIG. 3 is a diagram similar to FIG. 2 for explaining the movement of a movable lens. FIG. 4 is a flowchart for explaining the method of the present invention. 1...Light source, 2...Reflector, 3...Document stand,
4, 5, 7, 8...reflector, 6...movable lens,
9...Photosensitive drum, 10...Electric fan, 11...
Reflector, 12...copying machine body, 15...cover,
A...1:1 position detection element, B...82% position detection element, C...71% position detection element, M...Magnet.

Claims (1)

[Claims] 1. A lens position detection element is provided at a position corresponding to the magnification in the lens movement path, and the lens is moved according to the input of the magnification, and the lens is stopped based on the output of the position detection element corresponding to the input magnification. When a magnification different from the set magnification is input in a variable magnification copying machine, which sets the magnification by using A lens position control method characterized in that a magnification setting operation is performed by inputting the magnification, and when the magnification is in operation, the input of the magnification is invalidated and the magnification setting operation by the input is not performed.