JPS61163331A - Variable power controller of copying machine - Google Patents

Abstract

PURPOSE:To reduce the error of variable power setting by comparing the size of an image read by a signal of a solid-state image pickup element with a signal of the size of a preliminarily set transfer paper. CONSTITUTION:A mirror 7 on an optical path is switched while describing a sector to lead the light to a photosensitive body 8 or a solid-state image pickup element 9, and optical path lengths of them are equalized. The projection light is made incident on the element 9, and a linear index image a1 corresponding to the magnification at this time is projected onto the element 9, and a controller reads this position and compares it with the position of a linear index image a2 on the transfer paper which is preliminarily set and stored. If positions a1 and a2 are different from each other, a motor drives a lens 4 and mirrors 5 and 6 to perform the loop control, and varying of the magnification is terminated to start the copying operation when two positions coincide with each other. Thus, the variable power is set in accordance with a ratio of the size of the original to that of the transfer paper, and the solid-state image pickup element is used to perform the loop control, and the variable power control with less error is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an optical variable magnification device for a copying machine, and particularly to a drive control device thereof.

(Prior Art) A copying machine uses an optical system to project an original on a contact glass onto a photoreceptor to form an image.
Many cameras are equipped with a so-called variable magnification device that can provide a reduced image and an enlarged image in addition to a life-sized image.

This was accomplished by driving and controlling the lenses and mirror blocks of the optical system in accordance with the magnification.

The drive control system in the conventional variable magnification copying apparatus has means for storing numerical data corresponding to the magnification, and each time the magnification is input, the numerical data is read from the storage means, and the numerical data is There are those that drive the corresponding distance, and those that calculate and drive the distance to be driven every time a magnification is input, and also use a potentiometer (position-resistance value converter) to verify the distance. There are some methods that perform closed-loop control using, etc.

However, these methods all convert the lens position, mirror position, etc. into magnification, and do not verify the latent image actually formed on the surface of the photoreceptor.

Therefore, magnification errors may occur due to, for example, component tolerances.

Furthermore, as in Japanese Patent Laid-Open No. 59-111634, there is a system that detects the document size using a solid-state image sensor and calculates the magnification based on the ratio with the designated transfer paper size to control magnification. In this case as well, the size of the latent image formed by changing the magnification has not been verified.

(Objective) It is an object of the present invention to eliminate such drawbacks of the conventional example and to provide an optical magnification control device with small magnification error.

(Structure) For this purpose, the present invention provides a size signal w corresponding to the size Wl of the projected image of the original and the size W of the transfer paper specified in advance.
2 and controls the variable power driving device so that w, = wz based on the comparison result.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an embodiment of a document scanning type copying machine, in which light from an exposure lamp 2.2 that illuminates an exposure surface 1 becomes reflected light and passes through a first mirror 3, a lens 4, a second The light reaches the photoreceptor 8 through the third mirror 5.6 and the fourth mirror 7, and forms a latent image on the surface of the photoreceptor 8.

Here, the fourth mirror 7 can be stirred by a solenoid to be described later, and when it is stirred, it is at the position 7a, and the projection light reaches the solid-state image sensor 9.

FIG. 2 is a block diagram showing an example of a drive control circuit.

In the figure, reference numeral 10 denotes a magnification input means, which exchanges data with a control bag fil composed of a microprocessor (for example, a display signal is output from the control device 11).
.

The output of the control device 11 includes a solid-state image sensor 9, an exposure lamp 2, drive motors 12 and 14 via a driver, and a solenoid 15.
, PLLilIm circuit 17 is provided. The lens 4 is driven by a drive motor 12, and a mirror block 13 consisting of a second mirror 5 and a third mirror 6 is driven by a drive motor 12.
4.

Further, the fourth mirror 7 is driven by a solenoid 15.

Note that 16 is a motor and 18 is an encoder.

Now, when a magnification input signal is sent to the control device 11 by the magnification input means 10, as shown in the flowchart of FIG.
The input magnification is stored in the control device 11 (same as in step 11 and below), and in S2, the solenoid 15 is energized to fan the fourth mirror 7 in order to read the current magnification.
Turn on exposure lamp 2.2. As a result, projection light is incident on the solid-state image sensor 9. Now, if a linear index a0 in the document scanning direction is provided on the exposure surface 1 as shown in FIG.
A linear index image a is projected onto the solid-state image sensor 9 at a position corresponding to the magnification at that time.

Next, in 53, the control device 10 reads the signal of the solid-state image sensor 9, recognizes the position of the linear index image a, and determines the position of the linear index image a2 to be projected at the magnification stored in Sl. If the comparison is different, the lens drive motor 12 and the drive motor 14 of the mirror block 13 consisting of the second and third mirrors 5.6 are controlled to perform magnification change in S4, and the drive motor 14 of the mirror block 13 consisting of the second and third mirrors 5.6 is controlled again in S3.
The same operation, that is, closed-loop control, is carried out at , and the position of the linear index image a recognized from the signal of the solid-state image sensor 9 and the linear index image a2 to be projected at the magnification stored at Sl are determined. When the positions match, the process proceeds to 85, where the solenoid 15 is de-energized, the fourth mirror 7 is returned to its original position, the magnification change is completed, and the process proceeds to the copying operation.

According to the above, for example, the distance from the third mirror 6 to the surface of the photoreceptor 8 via the fourth mirror 7, and from the third mirror 6,
If the distance to the solid-state image sensor 9 is made equal, the size of the image projected onto the solid-state image sensor 9 will be equal to the size of the latent image formed on the surface of the photoreceptor 8. Magnification control with small magnification error is possible by performing closed-loop control to equalize the position signal of the index image provided on the exposure surface and the position signal of the index image determined by the magnification input from the operation unit. Become.

Note that even if the distance from the third mirror 6 to the surface of the photoreceptor 8 via the fourth mirror 7 is not equal to the distance from the third mirror 6 to the solid-state image sensor 9, the solid-state image sensor Since the position signal of the target image to be projected on the target image 9 is determined, it is possible to perform magnification change control with a small magnification error by closed-loop control as in the case where the distances are equal.

Although the index a is taken as position data in FIG. 3, the index 10 may be taken as data of a predetermined size as shown in FIG.

In other words, an index of a predetermined size is placed on the exposure surface! . and the fourth
The size of the index image projected onto the solid-state image sensor 9 in flow S3 in the figure! , and compares it with the size Il of the index to be projected at the magnification stored in sl, and performs the processing of 34 and S5 in the same manner as described above.

In the embodiment shown in FIG. 6, the image is projected onto the solid-state image sensor 9 based on predetermined position data a corresponding to the index position on the exposure surface 1 or the size of the index, or size data 10 and magnification m. It has a storage means 19 in which position data a2 or size data 12 of the projected image of the index is calculated in advance and the position data a2 or size data 18 is stored for each magnification. Every time a variable magnification input signal is sent to the control device 11, position data a8 or size data lt corresponding to the input magnification is read out from the storage means 19, and a projected image of the index read from the signal of the solid-state image sensor 9 is read out. position a
, or size l.

and based on the comparison results, the lens drive motor 12,
A variable magnification drive device consisting of a mirror block drive motor 14 is controlled.

The above constitutes the principle of the present invention, and is actually the seventh
As shown in the figure, instead of the index in Figure 5, the original 20
The size Wl of the projected image is compared with the size signal w2 corresponding to the pre-designated size W0 of the transfer paper, and the variable magnification drive device is controlled based on the comparison result so that w1=wt. . In this case, it is convenient if the size of the projected image of the document is read outside the imaging range. □According to the above, the size of the projected image that is the same size as the latent image formed on the photoconductor is detected, and the size of the projected image is equivalent to the predetermined size of the transfer paper. Since the variable magnification drive device is controlled so that the size signal is equal to the size signal of the transfer paper, the original image is not missing on the transfer paper (and there is no excess transfer paper surface, that is, the size of the transfer paper is It becomes possible to form an equal latent image on the photoreceptor.

(Effects) The present invention is as described above, and according to the variable magnification control device according to the present invention, the size of a latent image formed on a photoconductor is detected by using a solid-state image sensor, and a closed loop is performed. Therefore, it is possible to perform variable magnification control with small errors.

[Brief Description of the Drawings] Fig. 1 is a functional diagram showing an optical system according to an embodiment of the present invention;
Fig. 2 is a block diagram showing an example of a variable magnification drive control circuit, Fig. 3 is a functional diagram showing an example of an index, Fig. 4 is a flowchart showing control operation, and Fig. 5 is a function diagram showing another example of an index. 6 is a block diagram showing another example of the variable magnification drive control circuit, and FIG. 7 is a diagram showing a projection optical system according to an embodiment in which an actual document is used as an index. 9...Solid-state image sensor, 11...Control device, 2°...Manuscript. 4ml Three Agents Patent Attorney 2 Kenjibe K<;. Figure 1 Figure 5

Claims (1)

[Claims] A solid-state image sensor that receives a projected image of a document by an imaging optical system, a size of the projected image read by a signal from the solid-state image sensor, and a size signal corresponding to a predetermined size of transfer paper. A variable-magnification control device for a copying machine, comprising a control device that compares the following: and controls a variable-magnification drive device based on the comparison result.