JPH09236870A - Image projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the influence of external light and to satisfactorily receive light by a light receiving means, by providing a shutter for blocking off light which enters a housing after being transmitted through a screen. SOLUTION: In an observation state where the image of a microfilm F is projected on the screen 7 through an overhead mirror 9 and a reflection mirror 10, three cams 16, 22 and 23 stand still at a prescribed angle, and an overhead mirror table 13 is kept in an attitude where the mirror table 13 is rotated counterclockwise to the maximum. In this state, a connection shaft 32 is positioned at the lowest point, and the right shoulder part of a large diameter bevel gear 29 is depressed as low as possible, then, the shutter 27 is completely open. And when an image reading switch is depressed, a scanning motor 26 starts rotating so as to rotate three cams 16, 22 and 23 clockwise. In accordance with the rotation of the cams, the overhead mirror table 13 and the overhead mirror 9 are rotated clockwise, instantaneously, the shutter 27 is made in a closed state, then, the light (external light) entering the housing 12 after being transmitted through the screen 7 is completely blocked off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image projection apparatus for selectively projecting an image such as a microfilm on a light receiving means such as a transmissive screen or a line light receiving sensor.

[0002]

2. Description of the Related Art Conventionally, there is a microfilm scanner as an example of this type of apparatus. A microfilm scanner is a device for enlarging and projecting a microfilm image on a screen, switching the optical path of image light, projecting / scanning on an exposure unit such as a line sensor, and reading the image. As a screen of such an apparatus, a transmissive screen which is easy to see even if the surroundings are bright is generally used.

However, external light (hereinafter simply referred to as external light) that passes through the screen and enters the inside of the machine is
There is a problem that it adversely affects the reading of an image by a line sensor or the like. Further, at the time of image reading and exposure, there is a problem that the operator's eyes are liable to be injured because the movement in the machine and the distorted moving image are displayed on the screen.

[0004] Therefore, as a measure against the invasion of external light, the inside of the device casing is subjected to a frosting process or the like to reduce the internal reflection,
Attempts have been made to reduce the adverse effects of external light such as halation, but they have not eliminated the adverse effects on image reading.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art by: -preventing the influence of external light; -preventing annoying shadows and images from being projected on the screen during exposure. It is an object of the present invention to provide an image projection device capable of: -simple configuration.

[0006]

The present invention is an image projection apparatus characterized by the following configurations. (1) In an image projection device that selectively projects an image on a recording medium onto a transmission screen provided on a predetermined surface of an apparatus casing and a light receiving means provided inside the casing, the image transmission apparatus transmits the screen to transmit the casing. An image projection device, comprising a shutter that blocks light that enters the body.

(2) In an image projecting device for selectively projecting an image on a recording medium onto a transmission screen provided on a predetermined surface of an apparatus housing and a light receiving means provided in the housing, the image is projected on the screen. An image projection apparatus comprising a shutter that blocks light that passes through the screen and enters the housing when the light is projected onto the light receiving unit.

(3) A device housing, a transparent screen provided on a predetermined surface of the housing to project an image by a diffusion surface, a light receiving means provided in the housing, and a projection for projecting an image on a recording medium. A lens, a switching mirror for switching an optical path of a light beam from the projection lens to project an image of the recording medium on a transmission screen, and an exposure state for guiding the image to the light receiving means, and the switching mirror. An image projection apparatus comprising: a holder for holding a mirror; and a shutter that opens in the observation state and closes in the exposure state to block light that passes through the screen and enters the housing.

(4) A device housing, a transparent screen provided on a predetermined surface of the housing to project an image by a diffusion surface, a light receiving means provided in the housing, and a projection for projecting an image on a recording medium. A lens, a switching mirror for switching an optical path of a light beam from the projection lens to project an image of the recording medium on a transmission screen, and an exposure state for guiding the image to the light receiving means, and the switching mirror. And a shutter for holding a mirror and a shutter for opening in the observation state and closing in the exposure state to block light that passes through the screen and enters the housing. An image projecting device, characterized in that when a mirror is tilted to switch the optical path of a light beam from the projection lens, the rotational force of the holding table is transmitted to the shutter to open and close.

(5) It has an urging member for urging the shutter in a closing direction, and when the exposure state is returned to the observation state, the rotational force of the holding table may open the shutter against the urging force. The image projecting device according to (4).

(6) An image is scanned by moving the switching mirror in an exposed state (3)
The image projection device according to any one of (5) to (5).

(7) The image projector according to any one of (1) to (6), wherein the light receiving means is a light receiving sensor for reading a projected image by photoelectric conversion.

(8) The image projecting device according to any one of (1) to (6), wherein the light receiving means is a photoconductor used in an electrophotographic process.

<Operation> By providing the shutter,
In the exposure state, the external light that passes through the screen and enters the housing of the apparatus is blocked, and the light receiving unit can receive the light without being affected by the external light. Further, it is possible to prevent annoying shadows and images from being displayed on the screen.

Since the rotational force of the holding table holding the switching mirror is transmitted to the shutter to open and close the shutter, the structure of the apparatus is simplified.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a vertical cross-sectional model view showing a schematic structure of a microfilm scanner 1 which is an image projection apparatus adopting the present invention, and FIG. 2 is a cross-sectional model view thereof.

In the figure, reference numerals 2, 3, 4, and 5 are illumination optical systems, which reflect the light flux from the light source 2 and the light flux reflected by the spherical reflecting mirror 3 and returned to the light source 2 side by the mirror 5. The micro film F which is reflected and is sandwiched between a pair of glass plates (not shown) is illuminated via an optical system (field lens / condenser lens) 4.

A projection lens 6 projects the image of the microfilm F illuminated by the illumination optical system on the screen 7 or the line sensor 8 in an enlarged manner. Reference numerals 9, 10, and 11 are mirrors for guiding the light flux from the lens 6 to the screen 7 or the line sensor 8, and the optical path of the light flux is bent so as to be compactly housed in the machine casing 12. The mirror (ceiling mirror) 9 is provided on the ceiling mirror base 13 with its reflecting surface facing downward, and swings around an axis 14 passing through the intersection of the reflecting surface and the projection optical axis La, The optical path of the light flux from the projection lens 6 is changed by the swing.

A ceiling mirror base 1 for holding the ceiling mirror 9
3 is a shaft portion 13 in the left-right direction (direction perpendicular to the paper surface in FIG. 1)
b is pivotally supported on the side plate 12a of the machine casing 12, and the shaft portion 1
A roller 15 provided at the tip of an arm portion 13a fixed to 3b abuts on the outer peripheral cam surface of the scan cam 16 by its own weight, and the tilt of the ceiling mirror 9 is changed by following the cam surface.

As a mechanism for controlling the position of the line sensor 8 in conjunction with the inclination of the ceiling mirror 9, a slide base 18 is reciprocally attached to a slide shaft 17 provided at the rear of the apparatus 1, A sensor holding table 20 is swingably supported on the slide table 18.

A line sensor 8 and a slit 21 are fixedly mounted on the sensor holder 20, and the light receiving line of the line sensor 8 coincides with the swing center of the sensor holder 20.

An optical path length correction cam 22 and a sensor inclination correction cam 23 are integrally provided above the slide base 18,
The roller 19 of the slide base 18 (arm portion 18a) serves as the optical path length correction cam 22, and the arm portion 2 of the sensor holding base 20.
0a is attached to the sensor inclination correction cam 23 by the tension spring 2 respectively.
4 abuts. That is, the positions and orientations of the line sensor 8 and the slit 21 are determined by the two cams 22 and 23.

Scan cam 16 and optical path length correction cam 22
The sensor inclination correction cam 23 is connected to the sensor inclination correction cam 23 by a drive belt 25, and is rotated in the same direction and at the same speed by driving the scan motor 26. The angles of the cams 16, 22, and 23 can be arbitrarily controlled by a detection means (not shown).

The shutters 27 are provided at both inner ends of the screen 7 so as to be openable and closable, and in a closed state, light (external light) that passes through the screen 7 and enters the machine casing 12 can be completely covered. A small-diameter bevel gear 28 is provided on the upper part of the swing shaft 27a of the shutter 27 and rotates integrally with the shutter 27. A fan-shaped large-diameter bevel gear 29 meshes with the small-diameter bevel gear 28, and a tension spring 30 hooked on the large-diameter bevel gear 29.
The shutter 27 is urged so as to be in a closed state by the groove 29a provided in the large-diameter bevel gear 29 and the fixed shaft 31, and the shutter 27 is stopped at the position indicated by the chain double-dashed line in FIG. .

Further, the connecting shafts 32 protruding to both sides of the ceiling mirror base 13 have a right shoulder portion (of the device) of the large diameter bevel gear 29 when the ceiling mirror base 13 tilts forward, that is, rotates counterclockwise in FIG. The bevel gear 29 located on the opposite side is the left shoulder portion, and since it operates symmetrically altogether, only the side shown in FIG. 1 will be described below.) When the right shoulder is pushed down, the shutter 27 opens.

In the microfilm scanner 1 having the above-mentioned structure, the three cams 16, 22, and 23 are shown in the so-called observation state in which the image of the microfilm F is projected on the screen 7 through the ceiling mirror 9 and the reflection mirror 10. 1
And the ceiling mirror stand 13 maintains the posture in which it is most rotated counterclockwise. In this state, the connecting shaft 32
Is located at the lowest point, the right shoulder of the large-diameter bevel gear 29 is pushed down most, and the shutter 27 is completely open.

When an image reading switch (not shown) is pressed, the scan motor 26 starts rotating and the three cams 16, 22, 23 rotate clockwise. Along with this, the ceiling mirror base 13 and the ceiling mirror 9 rotate clockwise, and the shutter 27 is closed instantly. And the cams 16, 22,
When 23 reaches the angle shown in FIG. 3, the ceiling mirror 9 begins to reverse from clockwise to counterclockwise. At this time, the light at the edge of the image is incident on the line sensor 8 via the reflection mirror 11, and the reading of the image is started. Then, the ceiling mirror 9 rotates in conjunction with the rotation of the cams 16, 22, and 23, thereby scanning the image light projected on the line sensor 8.

The positions and postures of the line sensor 8 and the slit 21 are changed as follows in association with the rotation of the cams 16, 22, and 23. At the start of image reading (FIG. 3), the posture is the rearmost and the lowest. When the image center is read (FIG. 4), the posture changes to the forefront / intermediate posture, and when the image reading ends (FIG. 5), the posture returns to the rearmost position and changes to the most upward posture. That is, the optical path length is corrected so that the light receiving line of the line sensor 8 always coincides with the image forming position of the projected image, and the inclination is corrected so that the image light is incident on the line sensor 8 at a constant angle. This avoids image distortion due to a change in the optical path length, and avoids as much as possible the effects of dust adhering to the surface of the clear layer that protects the light receiving portion of the line sensor 8 and bubbles generated in the clear layer. .

Then, the reading is completed, and the three cams 1
When 6, 22, and 23 rotate further clockwise from the image reading position of FIG. 5, the observation state of FIG. 1 is restored. This time,
The connecting shaft 32 hits the right shoulder of the large diameter bevel gear 29,
The shutter 27 is opened by pressing down.

As described above, in the apparatus according to this embodiment, no image distortion occurs during reading. Further, since the observation state and the exposure state are switched by the mirror swing mechanism that performs the reading and scanning, no special switching means is required. Furthermore, since the shutter 7 is opened and closed in conjunction with the mirror swing mechanism,
External light can be blocked easily and reliably.

<Others>. The shutter is not limited to the one that opens and closes by transmitting the rotational force of the switching mirror (holding table), and may be independently controlled to close in the exposure state. Alternatively, it may be manually opened and closed. At this time, the closing of the shutter may be detected to start switching to the exposure state.

[0032] The shutter may be provided not only inside the housing but also outside.

.. The shape of the shutter is not limited to the double-door type as long as it blocks external light, it can be opened and closed on the left and right, the one that hangs the light-shielding curtain along the rail, and the one that is wound around the winding shaft and stored (open. Other shapes may be used, such as one that draws out the light-shielding curtain (state) to block (closes) external light. Further, external light may not be completely blocked as long as the light can be blocked to the extent that the adverse effect on the light received by the light receiving means can be eliminated or reduced.

[0034] Although it is desirable in terms of cost to mechanically open and close the shutter as described above, a liquid crystal shutter or the like may be used to switch between transmission and non-transmission (opening and closing). This can reduce the mechanical operation part.

.. The light receiving means may be a photoconductor used in an electrophotographic process. For example, the photosensitive surface of the photoconductor is moved in synchronization with the movement (swing) of a switching mirror or the like, scanning exposure is performed to form a latent image, and the latent image is developed with a developer to obtain a developer image. , Transfer the developer image onto the recording material
The image is formed by fixing.

[0036]

As described above, the following effects can be obtained by the present invention.

By providing the shutter for blocking the external light, the shutter can be closed in the exposure state to prevent the influence of the external light, and the light receiving means can favorably receive the light.
Also, because the movement inside the plane during switching and scanning, and the image that moves distorted with it, are not displayed on the screen,
The operator's eye fatigue can be reduced.

By using the movement of the switching mirror to open and close the shutter, the device structure can be simplified.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an image projection apparatus according to the present invention (observation state).

FIG. 2 is a cross-sectional view of an image projection device according to the present invention.

FIG. 3 is a vertical cross-sectional view of the image projection apparatus according to the present invention (exposure state / at the start of reading)

FIG. 4 is a vertical cross-sectional view of an image projection apparatus according to the present invention (exposure state / when image center is read)

FIG. 5 is a vertical cross-sectional view of the image projection apparatus according to the present invention (exposure state / after reading is completed).

[Explanation of Codes] F Microfilm 7 Screen 8 Line Sensor 9 Ceiling Mirror (Switching Mirror) 13 Ceiling Mirror Stand (Holding Stand) 27 Shutter 28 Small Diameter Bevel Gear 29 Large Diameter Bevel Gear 30 Tension Spring (Biasing Member) 32 Connecting Shaft

Claims (8)

[Claims] 1. An image projection apparatus for selectively projecting an image on a recording medium onto a transmission screen provided on a predetermined surface of an apparatus housing and a light receiving means provided in the housing, the image being transmitted through the screen. An image projecting device is provided with a shutter that blocks light that enters the housing. 2. An image projection apparatus for selectively projecting an image on a recording medium onto a transmission screen provided on a predetermined surface of an apparatus housing and a light receiving means provided in the housing, the image receiving apparatus receiving the image. An image projection apparatus comprising a shutter that blocks light that passes through the screen and enters the housing when the image is projected onto the means. 3. A device casing, a transmissive screen provided on a predetermined surface of the casing for displaying an image by a diffusing surface, a light receiving means provided in the casing, and a projection lens for projecting an image on a recording medium. And a switching mirror for switching between an observation state in which the optical path of the light flux from the projection lens is switched to project the image of the recording medium on a transmission screen and an exposure state in which the image is guided to the light receiving means, and the switching mirror. And a shutter that opens in the observation state and closes in the exposure state to block light that passes through the screen and enters the housing.
An image projection apparatus comprising: 4. An apparatus casing, a transmissive screen which is provided on a predetermined surface of the casing and projects an image by a diffusion surface, a light receiving means which is provided inside the casing, and a projection lens which projects an image on a recording medium. And a switching mirror for switching between an observation state in which the optical path of the light flux from the projection lens is switched to project the image of the recording medium on a transmission screen and an exposure state in which the image is guided to the light receiving means, and the switching mirror. And a shutter that opens in the observation state and closes in the exposure state to block light that passes through the screen and enters the housing.
And an image projection characterized in that when the holder is rotated to tilt the switching mirror to switch the optical path of the light flux from the projection lens, the rotational force of the holder is transmitted to the shutter to open and close. apparatus. 5. A urging member for urging the shutter in a closing direction, wherein when the exposure state returns to the observation state, the shutter is opened against the urging force by the rotational force of the holding table. The image projection device according to claim 4. 6. The image projection apparatus according to claim 3, wherein scanning of an image is performed by moving the switching mirror in an exposed state. 7. The image projection apparatus according to claim 1, wherein the light receiving unit is a light receiving sensor that reads a projected image by photoelectric conversion. 8. The image projection apparatus according to claim 1, wherein the light receiving unit is a photoconductor used in an electrophotographic process.