JPS6358430A - Copying device - Google Patents

Abstract

PURPOSE:To make clear copying of a stereoscopic part possible by stopping down a variable diaphragm means by the quantity of light equal to the quantity of exposure corresponding to the difference of maximum quantity of light emission and optimum quantity of light emission making the quantity of light emission of an illuminating lamp maximum at the time of stereoscopic copying. CONSTITUTION:In a state of plane copying switching, a controlling device 34 opens a variable aperture means 31 and controls an illuminating lamp 7 to optimum quantity of light emission. In a state of solid copying switching, the controlling device 34 makes the illuminating lamp 7 maximum quantity of light emission, and stops down the variable diaphragm means 31 by the quantity of light equal to the quantity of exposure corresponding to the difference of maximum quantity of light emission and optimum quantity of light emission. Thereby, maximum quantity of light emission raised from optimum quantity of light emission by a margin in safety etc. brought about by small frequency of use and small number of times of continuous use is obtained, and the depth of focus of an image forming lens 13 is deepened raising the stop value by the surplus quantity of exposure, and the stereoscopic part of a subject can be copied clearly.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an electrophotographic copying apparatus.

(Prior Art) Conventional electrophotographic copying devices are generally used for copying flat originals, and the system speed and aperture of the imaging lens are usually kept constant, and the amount of exposure depends on the amount of light emitted from the illumination lamp. It has been adjusted.

On the other hand, in recent years, there has been a technology that allows copying of three-dimensional objects, such as gears with bosses, wiring patterns on printed circuit boards after parts are attached, etc., such as JP-A-57-192972
This method is known from Japanese Patent Application Laid-open No. 57-191653, etc. These names change the relative position between the in-focus position of the imaging optical system and the document placement surface, and it is possible to copy by focusing on a part away from the document placement surface. can.

However, this method of copying three-dimensional objects requires movement of the optical system and the original table, making the apparatus and control complex. Moreover, only the portions of the three-dimensional object that are in focus are clearly reproduced.

To solve this problem, it is conceivable to use an imaging lens with a deep depth of field.

(Problem to be solved by the invention) By the way, as a lens with a deep depth of field, FNO
The one with a large focal path if, and the one with a long focal path if, FN.

Since the branch library has a large amount of light, it is necessary to brighten the illumination optical system and design the system speed of the copying machine to be low. Making the illumination optical system brighter is limited to the output of the illumination lamp, which is about 400W, due to both glare and temperature rise, and designing a system with a lower speed usually unnecessarily reduces the copy speed during copying. become. Furthermore, increasing the focal length f means increasing the optical path length between the document placement surface and the photoreceptor surface, which increases the size of the apparatus.

For these reasons, there is a limit to the use of an imaging lens with a deep depth of field, and it is still insufficient for copying three-dimensional objects.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a variable diaphragm means for an imaging lens, and an exposure device that controls the amount of light exposure based on the amount of light emitted from the illumination lamp and the aperture value of the lens. The exposure amount control means opens the variable diaphragm means for planar copying and sets the illumination lamp to the optimum light emission amount for three-dimensional copying. The present invention is characterized in that when the light emission amount of the illumination lamp is set to the maximum, the variable aperture means is configured to stop the light amount by an amount equal to the exposure amount corresponding to the difference between the maximum light emission amount and the optimum light emission amount.

(Function) The exposure amount control means is operated depending on whether the switching means is switched to two-dimensional copying or three-dimensional copying. In the plane copying switching state, the control means opens the variable aperture means,
Controls the lighting lamp to the optimum amount of light emission. As a result, although the depth of focus of the imaging lens is shallow due to the open aperture, there is no problem since it is plane copying, and a sufficient amount of exposure can be obtained by the optimum light emission amount of the illumination lamp in the open aperture state. Therefore, plane copying, which is frequently performed, can be carried out repeatedly and without difficulty using the optimum light emission amount of the illumination lamp.

Further, in the stereoscopic copying switching state, the control means controls the illumination lamp to the maximum light emission amount and the variable diaphragm means to reduce the light amount by an amount equal to the exposure amount corresponding to the difference between the maximum light emission amount and the optimum light emission amount.

As a result, it is possible to obtain the maximum light emission amount without any particular problem by increasing the light emission amount from the optimum light emission amount to the extent that there is a margin for safety due to the low frequency of use or continuous use, and then increasing the aperture value for the excess exposure amount and forming an image. By deepening the depth of field of the lens, the three-dimensional parts of the object can be reproduced more clearly.

(Embodiment) To explain one embodiment of the present invention shown in FIG. An image of an object 4 placed on the glass 3 is slit-exposed onto the photosensitive drum 2 by an exposure optical system 5 below the document placement glass 3.

The exposure optical system 5 includes an illumination lamp 7, its reflector 8, and a first movable mirror 9 mounted on a first movable table 6, second and third movable mirrors 11 and 12 disposed on a second movable table 10, An imaging lens 13 receives reflected light from the object 4 that has passed through the first, second, and third movable mirrors 9, 11, and 12, and directs the imaging light flux from the imaging lens 13 onto the photoreceptor drum 2. It consists of a fixed mirror 14, and an illumination lamp 7, a reflective shade 8, and a first movable mirror 9 are moved by the first movable table 6 in the direction of arrow a.
The second object 4 is scanned by being moved at a speed V in the direction of
The third movable mirror 11.12 is moved by the second movable table 10 at a speed of v/2 in the direction of the arrow a to keep the optical path length of the imaging lens 13 on the object side constant, and the image of the object 4 is is slit-exposed onto the photoreceptor drum 2.

The photosensitive drum 2 is driven to rotate in the direction of the arrow at a circumferential speed V, and is driven by image forming and transfer devices such as an eraser 23, a charger 24, a developing sleeve 25, a transfer charger 26, and a cleaning device 27 arranged around it. In action,
After forming and developing an electrostatic latent image of the subject image subjected to the slit exposure, the latent image is transferred onto a copying sheet that is fed in synchronization with the image on the photosensitive drum 2, and copies are made. The copy sheet after the transfer passes through a fixing device (not shown) and is then discharged to the outside of the main body 1.

The imaging lens 13 has a variable aperture means 31 and is controlled by a lens aperture control means 32. The lens aperture control means 32 uses an automatic exposure amount control means 34 in response to switching signals from a depth of focus up key (switching means) 33 and a depth of focus release key (switching means) 41 for switching between planar copying and three-dimensional copying. It is controlled together with the illumination lamp 7, and in the case of plane copying, the variable diaphragm means 31 is kept open, and the amount of light emitted by the illumination lamp 7 is adjusted so that the signal from the exposure sensor 35 in front of the imaging lens 13 becomes the optimum exposure amount. controlled. Note that the depth of focus up key 33 is a switching means.
The depth of focus increase release key 41 can also be replaced with one key that is switched each time it is operated. Furthermore, if there is no key input even after a certain period of time has elapsed since the end of copying, a microcomputer or the like can be used to automatically return to the plane copying state.

By the way, the light emitting capacity of the illumination lamp 7 is designed to provide an amount of light that is two to three times the standard exposure amount, so when copying an object 4 with a normal reflectance,
The illumination lamp 7 has a considerable amount of light emission. Therefore, the present invention utilizes the extra light emission amount of the illumination lamp 7 to limit the variable diaphragm means 31 to the maximum limit, thereby deepening the depth of field and facilitating the reproduction of three-dimensional objects.

For this control, the depth of focus up key 33 and depth of focus release key 41 are provided on the operation panel 36 of the main body 1, as shown in FIG. It is provided together with a lamp light emission amount display device 42 that indicates the optimum light emission amount of the illumination lamp 7.

Further, a depth of focus increase display lamp 43 is provided near the depth of focus up key 330, and when the depth of focus up key 33 is operated, the lamp 43 lights up to indicate that the depth of field is being amplified. It is. When this display is made, the depth of field is increased by increasing the number of steps from the optimal light emitting amount displayed on the lamp light emitting amount display device 42 to the maximum light emitting amount.

The operation panel 36 includes the above-mentioned stupid numeric keypad 51, a variable magnification key 52, a print key 53, and a copy number/multiply display device 54.
Also provided are an exposure density adjustment key 55, an exposure density display section 56, and the like.

FIG. 3 is a block wiring diagram for the control, in which the exposure amount control means 34 is composed of an automatic photometry circuit 61, a microcomputer (hereinafter referred to as microcomputer) 62, and an illumination lamp drive circuit 63, and the lens aperture control means A case is shown in which the means 32 is composed of a microcomputer 62 and a lens aperture drive circuit 64. An automatic photometry circuit 65, a depth of focus up key 33, and a depth of focus release key 41 are connected to the input section of the microcomputer 62, and a lens diaphragm drive circuit 64 and a drive circuit 63 for the illumination lamp 7 are connected to the output section of the microcomputer 62. ing.

Next, the control method will be explained.

In the plane copying state, the illumination lamp 7 is controlled by the microcomputer 62 so that the exposure amount detected by the exposure sensor 35 becomes the appropriate exposure amount as described above, and the light emission amount of the illumination lamp 7 at this time is the optimum light emission amount. It's the amount. If the user wants to increase the depth of field in order to copy a three-dimensional object from this state, the depth of focus up key 33 is pressed. Then, the signal is input to the microcomputer 62. When the three-dimensional object copying signal is input, the microcomputer 62 calculates the difference between the optimum light emission amount and the maximum light emission amount, and also calculates the lens aperture amount equivalent to the difference, and provides it to the lens aperture drive circuit 64. Further, a signal for maximizing the output of the illumination lamp 7 is given to the illumination lamp drive circuit 63. As a result, the variable aperture means 31 is apertured by the calculated aperture amount, and the illumination lamp 7 is brought to its maximum light emission amount. In this way, it is possible to make the depth of field as deep as possible by using the extra output of the illumination lamp 7, and it is possible to make clear copies of three-dimensional parts.

Now, if the focal length of the imaging lens 13 is f"180 va and the maximum aperture value F: 80, then if the maximum light output is 174 and the appropriate exposure is obtained (1:1 copy), the maximum light output is the maximum aperture. The appropriate exposure amount can be obtained by stopping down the aperture value from F:8 to F:16.

The formula for calculating the depth of field is Here, = f (1-1/β) Also, if the copy magnification is m, It is.

Now, if we assume that the optimal light output is 1/4 of the maximum light output of the illumination lamp for life-size copying using an imaging lens with f: 180 m and F: 8, then the aperture can be stopped from F8 to F16, so from the above equation, Depth of field at F8 is Xrll#3
．． 2. In contrast, the depth of field at F16 is double that of XFI6 #6.4 mm.

To return to planar copying, the depth of focus increase release key 41 may be released.

Note that the aperture value during stereoscopic copying is automatically determined based on the difference between the maximum light emission amount and the optimum light emission amount as described above, but it differs depending on the subject. For this reason, it is not immediately clear how much the variable diaphragm means 31 is stopped and how much the depth of focus is. However, in this embodiment, the optimum light emission amount is displayed on the light emission amount display device 42 based on the output from the automatic light metering circuit 65, and the operator is informed that the depth of field will be deepened by the number of steps to allow for the maximum light emission amount. I can let you know. However, it is possible to use or replace this display with a conversion scale for changes in depth of field.

Although the depth of field may be displayed on a flat surface, it is convenient to display it vertically around the document placement glass 3, for example.

(Effects of the Invention) According to the present invention, since it has the above-mentioned structure and operation, it is possible to copy clearly even a three-dimensional part, and for this purpose, an image is formed by the amount of extra light that can be obtained by maximizing the amount of light emitted from the illumination lamp at one point. Since you simply increase the aperture value of the lens to deepen the depth of field, there is no need to worry about the lighting lamp being particularly dazzling or raising the temperature of the surrounding area.

[Brief explanation of drawings]

FIG. 1 is a partial side view of the internal mechanism of a copying machine showing one embodiment of the present invention, FIG. 2 is a perspective view of an operation panel, and FIG. 3 is a block diagram of a control circuit.

Claims (1)

[Claims] (1) A variable aperture means for an imaging lens, an exposure amount control means for controlling the amount of exposure based on the amount of light emitted from an illumination lamp and a lens aperture value, and a switching means for switching between two-dimensional copying and three-dimensional copying, The quantity control means opens the variable aperture means and sets the illumination lamp to the optimum light emission amount during two-dimensional copying, and sets the light emission amount of the illumination lamp to the maximum and controls the variable aperture means between the maximum light emission amount and the optimum light emission amount during three-dimensional copying. A copying apparatus characterized in that the copying apparatus is configured to stop the light by an amount equal to the amount of exposure corresponding to the difference.