JPS623410B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image recording apparatus capable of switching between a reader mode in which an image of a document is projected onto a screen and a printer mode in which the image is projected onto a photoreceptor.

Conventionally, as this type of recording device, for example, in a reader printer, a reader optical path for projecting an image of a document such as a microfilm onto a screen and a printer optical path for projecting the image onto a photoreceptor are partially used. is being carried out. In order to switch between reader mode and printer mode, the reader mirror that forms the reader optical path is moved in and out of the optical path to switch between the two, but it is difficult to miniaturize the optical system, and it is difficult to drive the reader mirror. Since a special drive device is required, the structure of the device becomes complicated and the device becomes expensive.

Further, in this type of reader printer, a light receiving element is provided to detect the density of the original in order to adjust the density of the copied image, and the amount of exposure is controlled by the output signal of this light receiving element. In this method, when you press the copy switch to command the start of copying, the reader mirror moves out of the optical path and switches to printer mode, and while the image of the document is being exposed to the photoconductor, the light receiving element placed in the printer optical path is activated. The light from the document is detected and its density is detected, and the amount of illumination light or exposure time is controlled based on the detected density, but a portion of the printer optical path is blocked by the light receiving element or its mounting member.
There was a problem that the exposure amount decreased and exposure unevenness occurred on the surface of the photoreceptor, and there was also a problem that it could not be applied when copying was performed by slit exposure.

There is also a method of detecting the document density using a light-receiving element placed in the reader optical path during reader mode.
It is also known to detect the concentration by moving the photodetector in and out of the reader optical path, but both methods have the disadvantage that it is difficult to accurately detect the concentration because they are affected by external light. Since a drive device is provided to move the light receiving element into and out of the optical path, the device is complicated and expensive.

The present invention has been made in view of the above circumstances, and provides an image recording device that has a simple structure, can be miniaturized, and can accurately detect the density of a document and record an image by slit exposure. The purpose is to

The present invention will be explained below using specific examples shown in the drawings. FIG. 1 shows a copying machine to which the present invention is applied, in which a document such as a microfilm 1 is illuminated by an illumination device comprising an illumination lamp 2, a spherical reflector 3, and a condenser lens 4. Microfilm 1 of 1
The entire image of each frame is simultaneously projected onto a screen 8 by a projection lens 5 via fixed mirrors (reflection members) 6 and 7 placed at fixed positions. Reference numerals 10 and 11 denote scanning mirrors (reflecting members) that slit-expose and scan the image on the microfilm 1 onto the image recording photosensitive drum 12 rotating in the direction of arrow A; both mirror surfaces are
It forms a 90 degree angle. Scanning mirrors 10, 11
is fixedly supported on a support 13, which is connected to a drive source and which drives the scanning mirrors 10 and 11.
are moved back and forth in the directions of arrows B and B'. The moving speed of the scanning mirrors 10 and 11 is set to 1/2 of the circumferential speed of the photosensitive drum 12. Scanning mirror 10,1
1 has an elongated shape that projects a slit-shaped part of the entire image of one frame of the microfilm onto the photosensitive drum 12, and the mirrors 10 and 11 are integrated with the support 13 and are synchronized with the photosensitive drum 12. By moving the mirror 10 across the optical path of the projection lens 5 (in a direction perpendicular to the optical axis of the projection lens), the entire image of one frame to be copied is sequentially scanned and exposed onto the photosensitive drum 12 in the form of strips. Ru.

At the time of reading, the scanning mirrors 10 and 11
is placed in the position shown in FIG. 1, that is, the mirror 10 is stationary at a retracted position outside the optical path of the projection lens 5. At this time, the image of the microfilm 1 illuminated by the lamp 2 is projected onto the screen 8 via the fixed mirrors 6 and 7, and this image can be observed on the screen.

On the other hand, when switching from the reader mode to the printer mode, the support body 13 is moved in the direction of arrow B, and the scanning mirror 10 is moved into the optical path of the projection lens 10. That is, move the mirrors 10 and 11 in the direction B to the exposure start position in the optical path shown in FIG.
It moves in the B' direction, and scans and exposes the photosensitive drum 12 with the image light of the microfilm reflected by the scanning mirrors 10 and 11 while moving in the B' direction. When the mirrors 10 and 11 reach the exposure end position shown in FIG. 3, the scanning exposure of the image is completed.

Around the photosensitive drum 12, known image forming means (not shown) such as a charging device, a developing device, a transfer device, a cleaner, etc. are arranged, and copying is performed by electrophotography. After the exposure of the image onto the photosensitive drum is completed, the mirrors 10 and 11 continue to move in the direction B', and when they return to the retracted position shown in FIG. 1, they stop, and the printer mode is automatically switched to the reader mode. When making multiple copies, scan mirror 1
0 and 11 move back and forth between the exposure start position and the exposure end position as many times as necessary.

In the above embodiment, the scanning mirrors 10 and 11 are moved in the same direction, but they may be moved in different directions. Further, although the scanning mirror 10 is moved in a direction perpendicular to the optical axis of the projection lens, it may be moved in a different direction to scan the image. In either case, scanning mirrors 10, 11 must be moved synchronously.

In FIG. 4, the slit plate 14 has a slit 1
4a, is supported by a guide shaft 15 so as to be able to reciprocate in the C and C' directions shown by arrows, and has one end hooked around pulleys 16 and 17.
Fixed. A roller 19 is attached to the other end of the slit plate 14, and when the slit plate moves, the roller 19 moves while rotating on a rail (not shown) of the main body. The pulley 16 is connected to a drive source (motor) that moves the support 13, and is configured so that the slit plate 14 moves in synchronization with the movement of the scanning mirrors 10 and 11. The pulley 16 is rotated forward and backward by the drive source, and the slit plate 14 is thereby reciprocated.

A light-receiving element 20 that detects the image density of the original is a movable plate 21 movably disposed on the slit plate 14.
It is arranged near the slit 14a. The movable plate 21 is moved together with the light receiving element 20 in the E direction shown by the arrow by the wire 22, so that the light receiving element 20 is moved in the document scanning direction (B direction).
move in the direction perpendicular to. One end of the wire 22 is connected to a coil spring 2 with one end fixed to the slit plate 14.
3 and the other end is fixed to the main body, and as the slit plate 14 moves, a coil spring 23 expands and contracts via the wire 22, thereby causing the movable plate 21 to reciprocate in the E direction. The movable plate 21 is provided with a roller 24, which is loosely fitted into a groove reel 25 provided on the slit plate 14, and when the movable plate 21 moves, it moves while rotating along the groove rail 25. do. The light-receiving element 20 is made of a known photoelectric conversion element with a small light-receiving area, and detects the amount of light from the original. The output signal of the light-receiving element is sent to a known lamp brightness control circuit (not shown) through a flexible electric cord 26, and the lamp brightness control circuit controls the brightness of the lamp 2 based on the output of the light-receiving element 20 to adjust the density of the original. This ensures that the optimum exposure amount can be obtained.

Detection of the image density by the light receiving element is performed before the step of scanning and exposing the image onto the photosensitive drum. That is, when switching from the reader mode to the printer mode, the scanning mirrors 10 and 11 move from the retracted position toward the exposure start position, and this movement causes the light receiving element 20 to enter the optical path of the projection lens and image on the light receiving element 20. A projection optical path is formed. During this optical path formation, the lamp 2 lights up and the scanning mirror 1
0 and 11 are moving towards the start of exposure light receiving element 20
can detect the density of an image by receiving light from the film. The light receiving element 20 detects the maximum and minimum values of image density. Next, the scanning mirror 10,
When the film 11 moves from the exposure start position to the exposure end position, the current supplied to the lamp is controlled according to the output of the light receiving element, and the lamp illuminates the film with appropriate brightness.

While the mirrors 10 and 11 are moving in the direction B', a film image illuminated by a lamp 2 whose brightness is controlled is exposed onto the photosensitive drum 12.

In this embodiment, when the copy switch is turned on, the lamp 2 lights up, the scanning mirrors 10 and 11 and the slit plate 14 move in the direction B in synchronization, and the mirror 10 enters the optical path of the projection lens. A printer optical path is formed, and while the scanning mirror is moving in the B direction, the light receiving element 20 moves in the direction perpendicular to the scanning direction of the document, that is, in the slit 1, in synchronization with the movement of the slit plate 14.
4a, scans the document, and detects the density of a wide area of the image. After detecting a predetermined density of the original, the brightness of the lamp 2 is adjusted based on the maximum and minimum values of the detected values, and the brightness of the lamp 2 is set to an appropriate state according to the density of the original. Note that the moving speed of the scanning mirror in the B direction may be made faster than the moving speed in the B' direction in order to shorten the time. The image quality of the copied image may be adjusted by adjusting the exposure time, aperture, bias voltage of the developing device, etc. based on the output of the received light.
When the scanning mirrors 10 and 11 are placed at the exposure start position, the mirrors 10 and 11 move forward in the direction of arrow B' in synchronization with the rotation of the photosensitive drum 12, and scanning exposure of the image on the photosensitive drum is performed.

FIG. 5 shows the density detection area of the original by the light receiving element, and assumes that the image to be copied of the original is 35,
When the scanning mirrors 10 and 11 scan the image 35 in the direction B and the light receiving element 20 moves in the direction of the arrow E by the length of the arrow, the light receiving element 20 detects the density of the image area indicated by a straight line 38 having a certain width. That means you did it. Therefore, since the light-receiving element 20 scans the surface of the document, it is possible to accurately and reliably detect the density of the text and background portions of the document.

In the present invention, at least one light-receiving element may be provided, but a plurality of light-receiving elements or more may be provided.

Furthermore, although the location of the light receiving element is not limited to that in the embodiment, it is preferable to provide it on a slit plate near the photosensitive drum in order to accurately detect the density.

FIG. 6 shows another embodiment of the present invention, which differs from the previous embodiment in the method of moving the scanning mirror. The scanning mirrors 10 and 11 are provided on a movable table 120 in a relationship that intersects at right angles. Mobile platform 120
is supported by a support guide rod 122 so as to be able to swing around an axis 121 that coincides with the intersection line of the mirror surfaces of the mirrors 10 and 11.
It is configured to move in the directions of arrows B and B' along the arrows B and B'.

The scanning mirror 10 is placed in a retracted position outside the optical path of the projection lens 5 in the reader mode, and the movable table 120 moves in the direction of arrow B and placed in the optical path of the projection lens 5 in the printer mode. After the scanning mirror 10 moves to the exposure start position in the optical path,
The movable table 120 moves in the direction of arrow B' while rotating the shaft 121.
The photosensitive drum 12 rotates in the direction of the arrow C, thereby scanning and exposing an image to be copied onto the rotating photosensitive drum 12. In this embodiment, the scanning mirror 10,1
1 can be further downsized. The copying method is not limited to the embodiments, and various known copying methods may be applied. In addition to microfilm, a document original may be used and its reflected light may be utilized.

As described above, according to the present invention, when switching from the reader mode to the printer mode, it is only necessary to move the reflective member that scans and exposes the image, which simplifies the structure of the device and makes it possible to downsize the device. In addition, since the image density is detected while switching to the printer mode, it is possible to appropriately set the exposure amount, etc. before starting slit exposure on the photoreceptor, and the optical path switching process and density detection process can be combined. Therefore, the recording start time can be shortened. Furthermore, since the density is detected when the reader optical path is not formed, there is no influence from external light, and the image density can be accurately detected.
Further, by detecting the density by receiving the image light reflected by the reflecting member while the reflecting member is moving, it is possible to detect the density of the document over a wide range.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a copying machine showing one embodiment of the present invention, FIGS. 2 and 3 are diagrams explaining the operating state of the copying machine, FIG. 4 is a perspective view of a slit plate,
FIG. 5 is a diagram explaining the concentration detection area of the light receiving element;
FIG. 6 is a configuration diagram showing another embodiment of the scanning mirror. 5... Projection lens, 6, 7... Fixed mirror, 1
0, 11...Scanning mirror, 14...Slit plate.

Claims (1)

[Claims] 1. In an image recording device that can be switched between a reader mode in which images are projected onto a screen and a printer mode in which images are projected onto a photoreceptor, the device is placed in a retracted position outside the optical path of the projection lens in the reader mode, and within the optical path in the printer mode. a first reflecting member that enters the photoconductor, and a second reflecting member that moves in synchronization with the first reflecting member and reflects the light reflected by the first reflecting member toward the photoreceptor.
The reflective member, at least one light receiving element that detects light from the image and adjusts the quality of the recorded image according to the output thereof, and the first and second reflective members are moved in a direction transverse to the optical axis of the projection lens. having a driving means;
When the first reflecting member enters the optical path, the first and second reflecting members form an image projection optical path to the light receiving element, and while the first reflecting member is moving from the retracted position to the exposure start position, the image is projected by the light receiving element. An image recording apparatus characterized by detecting density and slit exposing an image onto a photoreceptor using first and second reflecting means while moving from an exposure start position to a retreat position.