JPS63254439A - Copying device - Google Patents

Abstract

PURPOSE:To surely, simply and easily detect the image density so that an image forming condition can be controlled, by positioning a rotary mirror for executing a scan of an image, and receiving a light beam by a photodetector provided on a fixed position. CONSTITUTION:An image projecting optical path is formed by irradiating an image of a microfilm 2 being an original from the lower part. In the reader mode, a rotary mirror 1 is positioned at a position shown by a full line in the figure, and the image is turned to a fixed mirror 3, thereafter, bent by the mirror 3, and enlarged and projected to a screen A. Subsequently, in the printer mode, the mirror 1 rotates to a print start position shown by an imaginary line, and executes a scan of the image by further rotating by a prescribed angle. In such a way, the image is brought to slit projection and exposure to the surface of a photosensitive body 7 through fixed mirrors 4, 5 and 6. An image density detecting means 21 is provided on a fixed position of the extended direction side along the mirror surface 9 of a photometric position, and plural pieces of photometric elements 22 are fixed and provided on the lower face of an intermediate base 23 being alight shielding plate, by which the image density can be detected surely.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to copying apparatuses such as reader printers and electronic copying machines. In other words, the document is illuminated with light from a light source,
The present invention relates to a copying apparatus that projects an image of the original onto an image receptor and copies it using an optical system including at least one rotating mirror that performs scanning by rotation.

``Prior Art'' In such a copying device, there are two methods for projecting the original image onto an image receptor: a scanning method in which the document is moved linearly, such as on a document table or film tray, and an optical system. There is a scanning method that moves the object.

Scanning methods that move the optical system can be further divided into mirror linear scanning methods, in which a part of the mirror is moved linearly, and mirror rotation scanning methods, in which a part of the mirror is rotated. The present invention relates to a copying apparatus using this mirror rotation scanning method.

In such a copying apparatus, density detection for each image, which is performed to adjust the light source brightness, distinguish between negative and positive originals, and control other image forming conditions, has been conventionally performed in the same way. In other words, the photometric element is connected to the reflected light of the projection optical path,
It is arranged to receive light comprehensively from a projected image at a position where transmitted light or the like is to be received, and a mirror, a photometric element, etc. are moved by a dedicated moving mechanism in order to receive such light.

"Problems to be Solved by the Invention" By the way, the following problems have been pointed out in such conventional examples.

In other words, since a dedicated moving mechanism is used, the device becomes large-scale, and problems such as troublesome control, complicated configuration, and cost are pointed out, as well as detection problems caused by movement errors in the moving system. It was pointed out that the reliability of the concentration was low.

In view of these circumstances, the present invention has been made in order to solve the problems of the conventional methods described above.The present invention has been made in order to solve the above-mentioned problems of the conventional example. The purpose of the present invention is to provide a copying apparatus that can reliably, simply and easily detect the image density. ,It is as follows.

This copying apparatus irradiates a document with light from a light source and projects an image of the document onto an image receptor using an optical system including at least one rotating mirror that performs scanning by rotation.

This rotating mirror can be rotated to a photometric position where its mirror surface is parallel to the incident optical axis of the projection optical path.

The image density detection means is provided at a fixed position on the extension direction side along the mirror surface of the photometry position, and includes an image density detection means including a photometry element that receives light from the projection optical path.

"Function" Since the copying apparatus according to the present invention is comprised of such means, it functions as follows.

When detecting image density prior to copying, the rotating mirror is first rotated and positioned at a predetermined photometric position.

Therefore, the projection light path is received by a photometric element provided at a predetermined position without going through a scanning optical system, and the image density is thereby detected by the image density detection means.

In this way, the detection of image density will be performed reliably, simply and easily.

"Example" The present invention will be described in detail below based on the example shown in the drawings.

First, an example of a reader printer, which is a copying device, will be explained.

FIG. 2 is an explanatory diagram of the optical system.

This reader printer uses a mirror rotation scanning method in which an image is scanned by rotating a rotating mirror l.

First, light from a light source such as an exposure lamp is condensed, illuminates the image on the microfilm 2 (original document) from below, and passes through, thereby forming a projection optical path. In the reader mode, the rotating mirror 1 is positioned at the reader position shown by the solid line in the figure, and the image is directed to the fixed reader mirror 3, then bent by the reader mirror 3 and projected in an enlarged manner onto the screen A. In the zero-order print mode,
The rotating mirror 1 rotates from a reader position indicated by a solid line in the drawing to a printing start position indicated by an imaginary line, and further rotates by a predetermined angle to scan an image. In this way the image is directed to the fixed print first mirror 4 and then to the print first mirror 4. Fixed printed second mirror5. The printed image is bent by a fixed third mirror 6, and exposed by slit projection onto the surface of a photoreceptor 7, which is an image receptor. Then, an electrostatic latent image is formed, developed with toner, and copied by a known process such as being transferred to copy paper.

Note that this reader printer switches between reader mode and print mode and scans images in print mode by rotating a single rotating mirror 1, so its optical system, drive system, and control system are simple. , which has the advantage of being facilitated.

The reader printer looks like this.

Next, the rotating mirror l will be explained in detail.

FIG. 1 shows an embodiment of the present invention and is an explanatory diagram of an optical system of a reader/printer. FIG. 3 is an enlarged view of the main part.

The rotating mirror l is rotated 1 to the photometry position shown by the broken line in the figure, where the mirror surface 9 is parallel to the incident optical axis 8 of the projection optical path.
Positioning is possible.

First, the rotation mechanism shown in FIG. 3 will be described.

The rotating mirror l is pivotally supported at the center by a horizontal rotating shaft 10, and one end of an arm 11 is fixed. The arm 11 has a length longer than the radius of the rotating mirror l and extends laterally, and teeth are formed on the other end, and the teeth are connected to a motor l1h12 of a motor M such as a pulse motor serving as a drive source. It meshes with the teeth formed in the Therefore, by driving the motor M in forward and reverse rotation, the motor shaft 12. Via the arm 11, the rotating mirror l is positioned one rotation between the reader position and the print start position, and is further rotated by a predetermined angle clockwise from the print start position to scan the image (see also Fig. 2). ).

Further, the motor shaft 12 is connected to a plunger of a first solenoid 13 via a connecting member 14, and the first solenoid 1
3, the motor shaft 12 and the motor M move from the normal position shown in the figure to the lateral retracted position as indicated by the arrow. Naturally, the motor shaft 12 and the arm 11 will also come out of engagement. On the other hand, by turning off the first solenoid 13, the motor shaft 12 and the motor M return to their normal positions.
The motor shaft 12 and the arm 11 will mesh again.

15 is a second arm 11 located near the other end of the arm 11 and facing above.
It is a solenoid, and its plunger is connected to the vicinity of the other end of the arm 11 via a connecting member 16. Therefore, when the first solenoid 13 is turned on and the motor shaft 12 etc. are moved to the retracted position, when the second solenoid 15 is turned on, the arm 11 is pulled upward around the rotation axis 10, and the rotation mirror 1 is moved from the horizontal position, for example. It further instantaneously rotates counterclockwise from the leader position tilted 60 degrees counterclockwise to the vertical photometry position shown by the broken line.

On the other hand, when the second solenoid 15 is turned off, the rotating mirror 1 rotates and returns from the photometry position to the reader position.

The rotation mechanism shown in FIG. 3 has this structure.

Note that the rotation mechanism of the rotating mirror 1 may be configured as follows, for example, regardless of the illustrated example.

That is, as in the illustrated example, the arm 11. First solenoid 13. The rotation shaft 10 of the rotation mirror 1 is directly connected to the motor shaft 12 of the motor M, such as a pulse motor, which is a drive source, without using the second solenoid 15, etc., so that only the rotation direction and rotation amount of the motor M can be controlled. , the rotating mirror l may be positioned at a reader position, a photometry position, a print start position, etc., and scanning may be performed from the print start position.

Next, the position detecting means for the rotating mirror 1 shown in FIG. 3 will be described.

The above reader position and photometry position of rotating mirror l.

The print start position and the like are detected, for example, as follows. That is, a disc 17 is attached to the rotation shaft 10 of the rotating mirror l, and slits 18, 19, 20 formed on the outer periphery of the disc 17 are used as sensors Sa such as transmission type photosensors for positioning and detection.

This is done by monitoring with Sb and Sc. At the leader position, the sensors Sa, Sb, and Sc are connected to the slit 18.
．． 19.20, and at the photometry position, only sensor Sa detects slit 19 and other sensors S
b and Sc are set so as not to detect the slits 18 and 20, and other settings are made to correspond to predetermined positions of the rotating mirror l. Note that the position detecting means is not limited to this illustrated example, and may be, for example, a method in which only one slit is formed, or various other methods.

The rotating mirror 1 has this structure.

Next, the image density detection means will be described.

The image density detection means 21 is provided at a fixed position on the extension direction side along the mirror surface 9 of the photometry position, and includes a photometry element 22 that receives light from the projection optical path. For example, a photoelectric conversion element such as a CdS element is used as the photometric element 22, and image density is detected based on the amount of received light and converted into an electrical signal. In the illustrated example, this photometric element 22 is a screen A.
A plurality of intermediate bases 23 are fixedly fixed to the lower surface of the intermediate base 23, which serves as a shield and front plate, and which are immovably fixed in the lower interior, corresponding to the areas of the projected image.

The image density detection signal from the image density detection means 21 is inputted to a control means such as a microcomputer via an amplifier, an A/D converter, etc., and a control signal corresponding to the detected value is calculated and output. That will happen. That is,
Depending on the detected image density, it is possible to control various image forming conditions, such as the following, for example.

First, automatic exposure is performed in which the exposure lamp voltage of the light source is set according to the image density and the light source brightness is adjusted.

Second, the image density determines whether the microfilm 2 as an original is negative or positive, and the toner that develops the electrostatic latent image on the photoreceptor 7 is positively charged.

A negative charge selection is made.

Thirdly, depending on the image density, control of exposure time, control of development bias voltage, control of condenser lens position,
Control 11 of other image forming conditions is performed.

The image density detection means 21 is configured as described above.

The above is the explanation of the configuration.

Next, the operation etc. will be explained.

FIG. 4 is a flowchart showing an example of control using the rotation ja side shown in FIG. 3, and the operation etc. will be explained below with reference to FIG. 4 as well.

When the power switch of the reader printer is turned on in step (2), it first enters the reader mode and the rotating mirror 1 is positioned at the reader position as follows.

That is, first, in steps ■, ■, ■, each sensor Sa, S
It is determined whether or not b and Sc have detected slit 1B and 19.20. Then, in step (2), the motor M is driven to rotate and the rotating mirror I is rotated until the sensors Sa, Sb, and Sc simultaneously detect the slits 1B and 19°20. Each sensor Sa, Sb, Sc has a slit 18.
, 19°20, the process proceeds to step (2), the motor M stops rotating, and the rotating mirror l is positioned at the leader position.

Next, warm-up is completed in step (2), and when the copy switch on the operation panel is turned on in step (2), the printing mode is entered, and first, the rotating mirror 1 is positioned at the photometry position as follows. The following description applies to single copy and multi-copy 1
The same applies to the second case.

That is, first, in step (2), the first solenoid 13 is turned on, and the motor M and its motor shaft 12 move from the illustrated normal position to the retracted position.

Next, in step [phase], the second solenoid 15 is turned on, and the rotating mirror 1 is rotated counterclockwise from the reader position to the photometry position. Whether or not the rotating mirror l has been positioned at the photometric position is determined in the next steps ■, o, and ■ when only the sensor Sa among the sensors Sa, Sb, and Sc detects the slit 19, and the other sensors Sb and Sc detect the slit 19. is determined by not detecting the slit 18°20.

If the sensors Sa, Sb, and Sc do not reach the above-mentioned detection state, necessary measures will be taken such as flashing a warning lamp as a trouble indication in step [phase].

When it is confirmed that the rotating mirror 1 is positioned at the photometric position, the process proceeds to the next step (2), where the photometric cable 22 of the image density detection means 21 detects the image density.

That is, the rotating mirror 1 is positioned at a photometric position where its mirror surface 9 is parallel to the incident optical axis 8 of the projection optical path. Therefore, the image is projected onto the photometric element 22 provided on the extension direction side along the mirror surface 9 via the projection optical path and is received without going through a scanning optical system, and each time the image density is detected. Become. In this way, image density detection is performed reliably, simply and easily.

Then, the flow advances to step [phase] (2), the second solenoid 15 and then the first solenoid 13 are turned off, and the rotating mirror l temporarily returns to the leader position.

Further, the image density detection signal from the image density detection means 21 is input to the microcomputer, and in step [phase], the image density detection signal is input to the microcomputer.
D sample data processing is performed and step [phase]
A control signal is output to set the lamp voltage of the light source according to the image density, and the brightness of the light source is adjusted. Further, various image forming conditions may be controlled in the same manner.

The flow then proceeds to step [phase] where copying is performed. That is, the motor M is turned on and off based on the position detection of the sensors Sa, Sb, and Sc, and the rotary mirror L is positioned at the print start position and then rotated by a predetermined angle to scan the image. Copying will take place. If multi-copy is determined in step (2), the process returns to step [phase] and the second and subsequent copies are made.

In this way, when the prescribed copy is completed in both single copy and multi copy cases, it is determined in step 0 whether the power switch is off, and if it is not off, the flow returns to step The flow ends.

The above is the explanation of the operation etc. based on the flowchart of FIG. 4.

Next, FIG. 5 is a flowchart showing an example of control in which the rotation mechanism of the rotating mirror l does not depend on the one shown in FIG. That is, as in the illustrated example, the arm 11. First solenoid 13. Without using the second solenoid 15 or the like, the rotation shaft 10 of the rotating mirror 1 is connected to a motor M such as a pulse motor as a driving source.
is directly connected to the morph shaft 12 of the motor M, and only by controlling the direction and amount of rotation of the motor M, the rotating mirror l can be positioned at the reader position, photometry position, print start position, etc., and scan from the print start position can be performed. The present invention relates to a rotation mechanism designed to perform the rotation, and an outline thereof will be explained below.

When the power switch is turned on in step @, the reader mode is first set and the rotation mirror 1 is positioned at the reader position as follows.

That is, first, it is determined whether the sensors Sa, Sb, and Sc have detected the slits 18, 19, and 20 in steps [Phase], [Phase], and [Phase]. And each sensor Sa, Sb
, Sc detects the slits 1B, 19°20 at the same time, the motor M is rotationally driven in step @, and the rotating mirror 1 is rotated. When the sensors Sa, Sb, and Sc detect the slit 18.19°20, the step [phase]
The motor M stops rotating and the rotating mirror I is positioned at the leader position.

Next, warm-up is completed in step @, and when the copy switch on the operation panel is turned on in step [phase], the print mode is entered, and first, the rotating mirror l is positioned at the photometry position as follows. Note that the following description applies in common to the case of single copy and the case of the first copy of multi-copy.

That is, first, the motor M is rotationally driven in step [phase], and the rotating mirror 1 is thereby rotated counterclockwise from the reader position to the photometry position. Whether or not the rotating mirror 1 is positioned at the photometric position is determined by the fact that only the sensor Sa among the sensors Sa, Sb, and Sc detects the slit 19 in the next step [phase], [phase], 0.
Other sensor Sb.

It is determined that Sc does not detect Surin 1-18.20.

Now, when the rotating mirror 1 is positioned at the photometry position, the motor M stops rotating in the next step (2).

Then, the process proceeds to step [phase], where the image density detection means 21
The photometric element 22 detects the image density. Note that the content is the same as that explained with reference to FIG. 4 above, so the explanation will be omitted.

Now, the image density detection signal from the image density detection means 21 is input to the microcomputer, and in step 0, the image density detection signal is inputted to the microcomputer.
D sample data processing is performed and step [phase]
A control signal is output to set the lamp voltage of the light source according to the image density, and the brightness of the light source is adjusted. Further, various image forming conditions may be controlled 1111 in the same manner.

The flow then proceeds to step [phase] where copying is performed. That is, the motor M is turned on and off based on the position detection of the sensors Sa, S, b, and Sc, and the rotating mirror l is positioned at the print start position and then further rotated by a predetermined angle to scan the image. The image will be copied. Note that if multi-copy is determined in step @, the process returns to step [phase] and the second and subsequent copies are performed.

In this way, when a specified copy is completed in both single copy and multi copy cases, it is determined in step @ whether the power switch is off, and if it is not off, the flow returns to step [phase] and the power switch is turned off. If so, the flow ends.

The above is the explanation of the operation etc. based on the flowchart of FIG. 5.

In the illustrated example, the photometric element 22 of the image density detection means 21 is fixed to the lower surface of an intermediate base 23, which is a light-shielding plate fixed immovably inside the screen A below. Therefore, the external light from the screen A is reliably blocked, and the light can be received only from the projection optical path without any adverse effects from the external light, so there is an advantage that more accurate image density detection can be performed.

"Effects of the Invention" As explained above, the copying apparatus according to the present invention ensures image density and N
Can be simply and easily detected. That is, the image density is detected stably by further rotating the rotary mirror slightly and receiving light by the photometric element of the fixed image density detection means without going through a scanning optical system or the like.

It is reliably realized with high reliability, has a simple configuration, is easy to control, is cost effective, and can appropriately control image forming conditions to obtain high-quality copies. Its effects are remarkable and significant, such as eradicating existing problems.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention and is an explanatory diagram of an optical system of a reader printer. FIG. 2 is an explanatory diagram of the optical system of a general reader printer. FIG. 3 is an enlarged view of the main part of FIG. 1, and FIG. 4 is a flowchart showing an example of the control. FIG. 5 is a flowchart 1 showing another control example. 1... Rotating mirror 2... Microfilm (original) 7... Photoreceptor (image receptor) 8... Incident optical axis 9... Mirror surface 21... Image density detection means 22... Photometric element Fig. 1 Fig. 2 Fig. 3, 1υ

Claims (1)

[Scope of Claims] A copying apparatus that irradiates an original with light from a light source and projects an image of the original onto an image receptor using an optical system that includes at least one rotating mirror that performs scanning by rotation. , the rotating mirror can be rotated and positioned at a photometric position where the mirror surface is parallel to the incident optical axis of the projection optical path, and is provided at a fixed position on the extension direction side along the mirror surface of the photometric position. A copying apparatus comprising: an image density detection means including a photometric element that receives light from the projection optical path.