Electronic still video camera having electro-developing recording medium, and image reader incorporated therein to electronically read image signals from developed image of such medium

An electronic still video camera having an electro-developing recording medium includes a photographing optical system for forming an optical image on an image-forming plane of the recording medium to record and develop the optical image therein. An image reader is provided for optically reading the image-forming plane to obtain image data from the recorded image of the recording medium. The image reader includes: a light source having a light emitting surface arranged parallel with the image-forming plane of the recording medium such that light beams emitted from the light emitting surface of the light source are perpendicularly directed to and passed through the image-forming plane of the recording medium; an image sensor having a light receiving surface oriented in the same direction as the light emitting surface of the light source; and an optical system constituted such that the light beams passed through the image-forming plane of the recording medium are directed to and focused at the light receiving surface of the image sensor.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an electronic still video camera having an 
electro-developing recording medium in which an optical image obtained 
through a photographing lens system is electronically and directly 
recorded and developed as a visible image in very little time. The present 
invention also relates to an arrangement of an image reader incorporated 
in such an electronic still video camera to electronically read image 
signals from a developed image of the electro-developing recording medium. 
2. Description of the Related Art 
Conventionally, silver halide photographic material is generally used as a 
material for recording an optical image. Silver halide photographic 
material has high optical sensitivity and high resolution, and the 
economical efficiency thereof is excellent. However, silver halide 
photographic material has drawbacks in that not only is the developing 
process cumbersome but also a visible image cannot be obtained at the same 
time as photography. A dry-type developing method has been developed to 
simplify the developing process. However, simultaneous development in 
which a visible image is obtained upon photography is impossible in the 
dry-type developing method. 
On the other hand, as non-silver-halide photographic materials, there are 
known electrophotographic materials, diazotype photographic materials and 
free-radical photographic materials and so on. In these materials, 
however, there is no material which has advantageous characteristics like 
silver halide photographic material, while being able to simultaneously 
develop and keep a visible image. Note that, electrophotographic materials 
have been used mainly in copying machines, since they can perform dry-type 
development and can simultaneously develop an electrostatic latent image, 
which is obtained by exposure, using toner. 
In such electrophotographic materials, recently, a photographic material 
has been developed, in which an optical image can be electronically and 
directly recorded and developed as a visible image in no time, the image 
so developed being similar to one obtained in a silver halide photographic 
material. A recording medium formed of such a recording material, in which 
a visible image is electronically and directly recorded and developed, is 
referred to as an electro-developing recording medium hereinafter. 
For example, Japanese Unexamined Patent Publication No. 5-2280 and U.S. 
Pat. No. 5,424,156 disclose one type of electro-developing recording 
medium comprising an electrostatic information recording medium and an 
electric charge keeping medium. The electrostatic information recording 
medium includes a photoconducting layer and an inorganic oxide material 
layer, and the electric charge keeping medium includes a liquid crystal 
display, both the media being combined to face each other with a small gap 
therebetween. In use, a voltage is applied between the electrostatic 
information recording medium and the electric charge keeping medium, and 
an optical image is formed on the electrostatic information recording 
medium during the application of the voltage. An electric charge 
distribution is produced over the electrostatic information recording 
medium in accordance with a light intensity distribution of the optical 
image formed thereon, so that the intensity of an electric field acts on 
the liquid crystal of the electric charge keeping medium in accordance 
with the electric charge distribution. Thus, an image derived from the 
optical image is reproduced in the electric charge keeping medium as a 
visible image. Namely, as soon as the optical image is formed on the 
electrostatic information recording medium, the image is developed in the 
electric charge keeping medium. 
When the electric charge keeping medium is a memory type liquid crystal 
display, the developed visible image can be kept therein even if the 
electric field is eliminated from the electro-developing recording medium. 
In the memory type liquid crystal display, the developed image can be 
erased by heating it to a given temperature. In this case, the same 
electro-developing recording medium can be repeatedly used for 
photographing. 
In an electronic still video camera having the electro-developing recording 
medium, there may be provided an image reader comprising a solid image 
line sensor such as a CCD line sensor for electronically reading image 
signals from a developed image of the electro-developing recording medium, 
and the read image signals obtained from the CCD image sensor may be 
processed in various manners. For example, the read image signals may be 
stored in a second recording medium such as an IC memory card, a floppy 
disk, a hard disk or the like. Also, the read image signals may be 
transferred from the camera to an external processing device such as a 
computer, a TV monitor and so on. 
The provision of the image reader results in the camera being bulky, 
because the image reader further comprises a light source for illuminating 
the developed image of the electro-developing recording medium, and an 
optical system for focusing the illuminated image at a light receiving 
surface of the CCD line sensor, and also because the image reader must be 
moved such that the developed image of the electro-developing recording 
medium can be scanned with the light source associated with the CCD line 
sensor. Accordingly, it is desirable that the image reader should be 
compactly arranged for reduction of the bulk of the camera. 
SUMMARY OF THE INVENTION 
Therefore, an object of the present invention is to provide an electronic 
still video camera having an electro-developing recording medium, and 
constituted such that an image reader for electronically reading out an 
image recorded and developed on the electro-developing recording medium is 
compactly arranged so that a size of the camera becomes as small as 
possible. 
Another object of the present invention is to provide a compactly arranged 
image reader used in such an electronic still video camera. 
In accordance with a first aspect of the present invention, there is 
provided an electronic still video camera having an electro-developing 
recording medium, comprising: photographing means for forming an optical 
image on an image-forming plane of the electro-developing recording medium 
to record and develop the optical image therein; and image-sensing means 
for optically sensing to obtain image data from the recorded image of the 
electro-developing recording medium, wherein the image-sensing means 
includes a light source having a light emitting surface arranged parallel 
with the image-forming plane of the electro-developing recording medium 
such that light beams emitted from the light emitting surface of the light 
source are perpendicularly directed to and passed through the 
image-forming plane of the electro-developing recording medium, an image 
sensor having a light receiving surface oriented in the same direction as 
the light emitting surface of the light source, and an optical system 
constituted such that the light beams passed through the image-forming 
plane of the electro-developing recording medium are directed to and 
focused at the light receiving surface of the image sensor. 
In accordance with a second aspect of the present invention, there is 
provided an image reader used in an electronic still video camera having 
an electro-developing recording medium, comprising image-sensing means for 
optically sensing to obtain image data from a recorded image of the 
electro-developing recording medium, wherein the image-sensing means 
includes a light source having a light emitting surface arranged parallel 
with the image-forming plane of the electro-developing recording medium 
such that light beams emitted from the light emitting surface of the light 
source are perpendicularly directed to and passed through the 
image-forming plane of the electro-developing recording medium, an image 
sensor having a light receiving surface oriented in the same direction as 
the light emitting surface of the light source, and an optical system 
constituted such that the light beams passed through the image-forming 
plane of the electro-developing recording medium are directed to and 
focused at the light receiving surface of the image sensor. 
In the image-sensing means as mentioned above, the image sensor may be 
arranged such that the light receiving surface thereof is included in an 
extension of the image-forming plane of the electro-developing recording 
medium. Preferably, the image sensor of the image-sensing means is 
constituted as a line sensor, and the light source of the image-sensing 
means is constituted as a linear light source. The line sensor and the 
linear light source are associated with each other such that they are 
relatively movable with respect to the electro-developing recording 
medium, whereby the image-forming plane thereof is scanned with the light 
beams emitted from the linear light source. More preferably, the line 
sensor and the linear light source are supported by a carriage member 
which is movable with respect to the electro-developing recording medium, 
and the optical system of the image-sensing means is immovably provided 
with respect to the carriage member. 
The optical system may include a converging lens or image-forming lens, and 
a pair of reflectors associated therewith, wherein the light beams emitted 
from the linear light source and passing through the electro-developing 
recording medium are directed to one of the reflectors, and are then 
reflected to the image-forming lens. The light beams passing through the 
image-forming lens are directed to the other reflector, and are then 
reflected to the light receiving surface of the line sensor. 
Preferably, the electro-developing recording medium comprises an 
electrostatic information recording medium and an electric charge keeping 
medium. The electrostatic information recording medium includes a 
photoconducting layer and an inorganic oxide material layer, and the 
electric charge keeping medium includes a liquid crystal display which 
preferably comprises a memory type liquid crystal display. 
In accordance with a third aspect of the present invention, an image reader 
is provided for electronically reading an image recorded and developed on 
an image-forming plane of an electro-developing recording medium. The 
image reader includes light source means disposed at one side of the 
image-forming plane of the electro-developing recording medium for 
illuminating the image-forming plane of the electro-developing recording 
medium; image-sensing means disposed at the one side of the image-forming 
plane of the electro-developing recording medium for optically sensing to 
obtain image data from the image recorded and developed thereon; and 
image-forming optical system means disposed at the other side of the 
image-forming plane of the electro-developing recording medium and 
including a converging lens defining two focal planes, and two reflectors 
associated therewith, the converging lens and two reflectors being 
arranged such that the focal planes defined by the converging lens are 
consistent with a light emitting surface of the light source means and a 
light receiving surface of the image-sensing means. 
In this image reader, the two reflectors may be arranged at sides of the 
converging lens such that light beams emitting from the light emitting 
surface of the light source means and passing through the image-forming 
plane of the electro-developing recording medium are reflected and 
directed to the converging lens along an optical axis thereof, and such 
that the light beams passing through the converging lens are reflected and 
directed to the light receiving surface of the image-sensing means.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 is an external view of a first embodiment of an electronic still 
video camera having an electro-developing recording medium, according to 
the present invention. 
When viewing a camera body 11 from a front side thereof, a photographing 
optical system 12 is provided on approximately a central portion of a 
front surface of the camera body 11, and an electronic flash 13 is 
disposed on the front surface of the camera body 11 at a right side of and 
above the photographing optical system 12. A release switch 14 is provided 
on the side opposite to the electronic flash 13. On an upper surface of 
the camera body 11, a view finder 15 is provided at the center portion 
thereof, and operation switches including a scan start switch 16 are 
provided on a side of the view finder 15. On a side surface of the camera 
body 11, an output terminal connector 17 is provided at a lower portion 
thereof so that an image signal obtained by the camera can be outputted to 
an external recording device. 
FIG. 2 shows a block diagram of the still video camera as mentioned above, 
in which a system control circuit 20 including a micro-computer or 
micro-processor is provided to control the still video camera as a whole. 
The photographing optical system 12 has a plurality of lens groups and an 
aperture 12a. An electro-developing recording medium 30 is disposed behind 
the photographing optical system 12, and a quick return mirror 21 is 
placed between the photographing optical system 12 and the 
electro-developing recording medium 30. A shutter 22 is provided between 
the quick return mirror 21 and the electro-developing recording medium 30. 
A focusing glass 23a included in a view finder optical system 23 is 
disposed above the quick return mirror 21. 
The aperture 12a, the quick return mirror 21 and the shutter 22 are driven 
by an iris drive circuit 24, a mirror drive circuit 25 and a shutter drive 
circuit 26, respectively. These drive circuits 24, 25 and 26 are 
controlled by an exposure control circuit 27 which is energized in 
accordance with a command signal outputted by the system control circuit 
20. 
While an exposure is controlled, an opening degree of the aperture 12a is 
adjusted by the iris drive circuit 24 under control of the exposure 
control circuit 27 based on an output signal of a photometry sensor 28. 
The quick return mirror 21 is usually set to a down-position (an inclining 
position shown by the solid line in the drawing), and thus a light beam 
passing through the photographing optical system 12 is led to the 
view-finder optical system 23, so that an object to be photographed can be 
observed by a photographer. When a photographing operation is carried out, 
the quick return mirror 21 is rotated upward by the mirror drive circuit 
25, and is then set to an up-position (a horizontal position shown by the 
broken line in the drawing), so that the light beam is directed to the 
shutter 22. 
The shutter 22 is usually closed, and upon performing a photographing 
operation, the shutter 22 is opened over a given period of time by the 
shutter drive circuit 26 under control of the exposure control circuit 27, 
and thus light beams passing through the photographing optical system 12 
and the shutter 22 are led to the electro-developing recording medium 30, 
resulting in forming a two-dimensional optical image thereon. 
A voltage is applied to the electro-developing recording medium 30 under 
control of a recording medium drive circuit 41. By exposing the 
electro-developing recording medium 30 while applying the voltage, an 
image formed by the photographing optical system 12 is developed on the 
electro-developing recording medium 30 as a visible image. Note that the 
recording medium drive circuit 41 is energized in accordance with a 
command signal outputted by the system control circuit 20. 
An image reader or scanning mechanism 50 is provided in the vicinity of the 
electro-developing recording medium 30, and comprises a linear light 
source 42 including an LED (light emitting diode) array or a plurality of 
light emitting diodes aligned with each other, and a collimater lens for 
converting the light beams, emitted therefrom, into parallel light beams. 
Namely, the light source 42 has a linear light emitting surface for 
illuminating the electro-developing recording medium 30. The scanning 
mechanism 50 also comprises a line sensor 44 constituted as a 
one-dimensional CCD sensor having, for example, 2,000 pixels, and forming 
a linear light receiving surface, and serving as a 
photoelectric-conversion device for sensing and converting an optical 
image into electric pixel signals. 
The scanning mechanism 50 further comprises a movable carriage member 52 by 
which the linear light source 42 and the line image sensor 44 are 
supported. The carriage member 52 is perpendicularly moved with respect to 
an optical axis defined by the photographing optical system 12, such that 
the electro-developing recording medium 30 is scanned with light beams 
emitted from the linear light source 42. During the scanning operation, 
the light beams passing through the electro-developing recording medium 30 
are directed to the linear light receiving surface of the line sensor 44 
by an optical system 43. The optical system 43 forms a part of the 
scanning mechanism 50, but it is immovably provided behind the 
electro-developing recording medium 30 and the carriage member 52. 
ON and OFF control of the light source 42 is performed by a light source 
drive circuit 45. Reading of the pixel signals from the line sensor 44 is 
controlled by a line sensor drive circuit 47. Movement of the carriage 
member 52 of the scanning mechanism 50 is controlled by a scanner drive 
circuit 46. The drive circuits 45, 46 and 47 are energized by the system 
control circuit 20. 
The pixel signals sensed and read out of the line sensor 44 are amplified 
by an amplifier 61, and are then converted to digital pixel signals by an 
analog-digital (A/D) converter 62. The digital pixel signals are subjected 
to a shading correction, a gamma correction and so on by an image 
processing circuit 63 under control of the system control circuit 20, and 
are then temporarily stored in a memory 64 which includes an EEPROM having 
correction data for the shading correction. Note, the memory 64 may have a 
capacity for storing a single-line of digital pixel signals outputted from 
the line senor 44 or may have a capacity for storing a single-frame of 
digital pixel signals obtained by a completion of the scanning operation 
of the scanning mechanism 50. 
The pixel signals outputted from the memory 64 may be optionally inputted 
into an interface circuit 65 through the image process circuit 63. In this 
case, the pixel signals are subjected to a given processing such as a 
format-conversion processing and so on, and are then outputted to, for 
example, an external monitor device (not shown) through the output 
terminal connector 17. Also, the pixel signals outputted from the image 
process circuit 63 may be recorded on, for example, a second recording 
medium, such as an IC memory card, a floppy disk, a detachable hard disk 
or the like, in an image recording device 67 therefor. In this case, the 
pixel signals are subjected to a given processing such as an 
image-compression processing and a format-conversion processing in a 
recording device control circuit 66. The interface circuit 65 and the 
recording device control circuit 66 are energized in accordance with a 
command signal outputted from the system control circuit 20. 
The release switch 14 and the scan start switch 16 are connected to the 
system control circuit 20, and the photographing operation and the 
scanning operation as mentioned above are executed by turning the switches 
ON. A display device 68, which may be constituted as an LCD (liquid 
crystal display) panel, is provided on a rear surface of the camera body 
11 at a suitable location thereof, and is connected to system control 
circuit 20 to display various setting conditions of the still video 
camera. Also, an electronic flash drive circuit 69 is connected to the 
system control circuit 20 to control a flashing operation of the 
electronic flash 13. 
FIG. 3 shows an arrangement of the optical reader or scanning mechanism 50. 
As mentioned above, the carriage member 52 of the scanning mechanism 50 is 
perpendicularly moved with respect to the optical axis defined by the 
photographing optical system 12, such that the electro-developing 
recording medium 30 is scanned with the parallel light beams emitted from 
the linear light source 42. The linear light source 42 and the line sensor 
44 are of suitable length to completely cover and extend over one 
horizontal scanning line of the image formed on the electro-developing 
recording medium 30. The movement of the carriage member 52 is carried out 
by a scan drive motor (not shown) such as a stepping motor, a servo-motor 
or the like, which is driven by the scanner drive circuit 46 (FIG. 2). The 
light source 42 and the line sensor 44 supported by the carriage member 52 
are separated from each other by a distance D in the direction of movement 
of the carriage member 52. 
When the photographing operation is executed, the carriage member 52 is 
removed from an optical path between the photographing optical system 12 
and the electro-developing recording medium 30, and is positioned at a 
lower position or removal position below the electro-developing recording 
medium 30. when the scanning operation is initiated, the carriage member 
52 is moved upward from the removal position to a scanning start position. 
Then, the carriage member 52 is intermittently moved step by step from the 
scanning start position toward an upper position, whereby the 
electro-developing recording medium 30 is scanned by the linear light 
source 42. 
In FIG. 3, the linear light source 42 is arranged such that the linear 
light emitting surface thereof is oriented to and extended parallel with 
an image-forming plane 30a of the electro-developing recording medium 30 
on which an image is recorded and developed. Thus, the light beams emitted 
from the light emitting surface of the light source 42 are perpendicularly 
directed to and are passed through the image-forming plane 30a of the 
electro-developing recording medium 30. Also, the image sensor 44 is 
arranged such that the light receiving surface thereof is oriented in the 
same direction as the linear light emitting surface of the light source 
42, and the optical system 43 is constituted such that the light beams 
emitted from the light source and passing through the electro-developing 
recording medium 30 are directed to and focused on the light receiving 
surface of the line sensor 44. 
In particular, the optical system 43 includes a converging lens or 
image-forming lens 43a, and a pair of total reflecting mirrors or 
reflectors 43b and 43c associated therewith. The image-forming lens 43a is 
arranged such that an an optical axis thereof is perpendicular with 
respect to the optical axis defined by the photographing optical system 
12, and the reflectors 43a and 43c are symmetrically arranged at both 
sides of the image-forming lens 43a with respect to the center thereof, 
and are inclined so as to define an angle of 45 degrees (or 135 degrees) 
with respect to the optical axis of the image-forming lens 43a. A distance 
between the centers of the reflectors 43b and 43c of the optical system 43 
corresponds to the distance D between the optical axis of the linear light 
source 42 and the line sensor 44, and the reflectors 43b and 43c are 
sufficiently extended so as to cover the image-forming plane 30a of the 
electro-developing recording medium 30. Also, the optical system 43 has a 
magnification of one, and is constituted such that an image recorded and 
developed on the image-forming plane 30a of the electro-developing 
recording medium 30 is focused and formed as a life-sized aerial image on 
a focal plane 44a in which the light receiving surface of the image sensor 
44 is included. 
With the arrangement as mentioned above, during the scanning operation, a 
linear segment of the image developed by the electro-developing recording 
medium 30 is illuminated by the linear light source 42, and the light 
beams passing through the image-forming plane 30a of the 
electro-developing recording medium 30 are directed to the image-forming 
lens 43a due to the reflector 43b. Then, the light beams passing through 
the image-forming lens 43a are directed to and focused on the linear light 
receiving surface of the line sensor 44 due to the reflector 43c. 
FIG. 4 shows a structure of the electro-developing recording medium 30, 
which is identical with that disclosed in Japanese Unexamined Patent 
Publication No. 5-2280 and U.S. Pat. No. 5,424,156, the disclosure details 
of which are expressly incorporated herein by reference in their entirety. 
The electro-developing recording medium 30 comprises an electrostatic 
information recording medium 31 and an electric charge keeping medium 32, 
and a voltage is applied therebetween by an electric power source 33, 
illustrated symbolically in FIG. 4. The electric power source 33 
corresponds to the recording medium drive circuit 41, and a recording 
medium activating signal (a voltage signal) is applied from the recording 
medium drive circuit 41 (i.e., the electric power source 33) to the 
electro-developing recording medium 30 during the photographing operation. 
The electrostatic information recording medium 31 is formed by laminating a 
base plate 34, an electrode layer 35, an inorganic oxide material layer 36 
and a photoconducting layer 37. The photoconducting layer 37 is formed by 
laminating an electric charge generating layer 37a and an electric charge 
transferring layer 37b. The electric charge keeping medium 32 is made by 
confining liquid crystal 40 between a liquid crystal supporting plate 38 
and a liquid crystal electrode layer 39. Namely, the liquid crystal 40 is 
confined as a film-like layer between the supporting plate 38 and the 
electrode layer 39, and this film-like liquid crystal forms the 
image-forming plane 30a (FIG. 3). The electric charge transferring layer 
37b of the photoconducting layer 37 and the liquid crystal supporting 
plate 38 of the electric charge keeping medium 32 face each other with a 
small gap therebetween. Note, as is apparent from FIG. 4, the whole 
structure of the electro-developing recording medium 30 is transparent. 
When the electric power source 33 is turned ON, or when the recording 
medium drive circuit 41 is energized, a voltage signal or recording medium 
activating signal is applied between the electrostatic information 
recording medium 31 and the electric charge keeping medium 32, i.e., 
between the electrode layer 35 and the liquid crystal electrode layer 39. 
When an optical image is formed on the electrostatic information recording 
medium 31 by the photographing optical system 12 during the application of 
the voltage signal, an electric charge distribution is produced over the 
electrostatic information recording medium 31 in accordance with a light 
intensity distribution of the optical image formed thereon, so that the 
intensity of an electric field acts on the liquid crystal 40 of the 
electric charge keeping medium 32 in accordance with the electric charge 
distribution. Thus, an image derived from the optical image is reproduced 
in the liquid crystal 40 as a visible image. Namely, as soon as the 
optical image is formed on the electrostatic information recording medium 
31, the image is developed in the electric charge keeping medium 32. 
In this embodiment, since the electric charge keeping medium 32 is 
constituted as a memory type liquid crystal display, the developed visible 
image can be kept therein even if the electric field is eliminated from 
the electro-developing recording medium 30. In the memory type liquid 
crystal display, the developed image can be erased by heating it to a 
given temperature, using a suitable heater (not shown). In this way, the 
same electro-developing recording medium 30 can be repeatedly used for 
photographing. 
FIG. 5 shows a timing chart for explaining a whole operation of the camera, 
and FIG. 6 shows a flowchart for explaining a photographing operation of 
the camera. With reference to these drawings, the photographing operation 
will be explained below. 
At step 101, it is determined whether or not the release switch 14 has been 
turned ON. If the turn-ON of the release switch 14 has been carried out, a 
command signal for executing the photographing operation is made ON 
(reference "S11" in FIG. 5), and is inputted to the system control circuit 
20. 
At step 102, an output signal of the photometry sensor 28, i.e., a 
photometry value, is sensed and fetched by the system control circuit 20, 
and then the control proceeds to step 103, in which an exposure 
calculation is started based on the fetched photometry value (reference 
"S12" in FIG. 5). After a predetermined period of time has elapsed from 
the ON operation of the release switch 14, the control proceeds to step 
104, in which a recording medium activating signal outputted from the 
recording medium drive circuit 41 to the electro-developing recording 
medium 30 is made ON (reference "S13" in FIG. 5). Namely, the recording 
medium activating signal is changed from the low level to the high level, 
so that the activating voltage is applied between the electrostatic 
information recording medium 31 and the electric charge keeping medium 32. 
Then, at step 105, it is determined whether or not the exposure 
calculation has been completed. When the exposure calculation has been 
completed (reference "S14" in FIG. 5), the procedures necessary for the 
photographing operation are subsequently carried out in the following 
steps on the basis of the calculated result. 
At step 106, an opening area of the aperture 12a is adjusted in accordance 
with the calculated result. Note, since the aperture 12a initially has a 
fully-open area, the adjustment of the aperture 12a is usually carried out 
such that the fully-open area thereof is made smaller (reference "S15" in 
FIG. 5). Also, at step 106, the quick return mirror 21 is changed from the 
down-position to the up-position (reference "S16" in FIG. 5). 
At step 107, it is determined whether or not the quick return mirror 21 has 
been changed from the down-position to the up-position, and whether or not 
the adjustment of the aperture 12a has been completed. When the change of 
the quick return mirror 21 from the down-position to the up-position and 
the adjustment of the aperture 12a are completed, the control proceeds to 
step 108, in which the shutter 22 is opened (reference "S17" in FIG. 5), 
whereby an optical image is focused and formed on the electro-developing 
recording medium 30 in the above-mentioned manner. 
At step 109, it is determined whether or not an exposure period of time, 
which is designated by the calculated result, has elapsed. When the 
exposure period of time has elapsed, i.e., when the exposure has been 
completed, the control proceeds to step 110, in which the shutter 22 is 
closed (reference "S18" in FIG. 5). After the closing of the shutter 22 is 
completed, the control proceeds to step 111, in which the quick return 
mirror 21 is returned from the up-position to the down-position (reference 
"S19" in FIG. 5), and in which the opening area of the aperture 12a is 
returned to the fully-open area (reference "S20" in FIG. 5). Then, at step 
112, the output voltage of the recording medium activating signal is made 
OFF (reference "S211" in FIG. 5), i.e., the recording medium activating 
signal is returned from the high level to the low level. 
Namely, the output of the recording medium activating signal to the 
electro-developing recording medium 30 is kept on at least during the 
period of time during which the shutter 22 is opened, so that recording 
and development of the optical image can be carried out in the 
electro-developing recording medium 30. As mentioned above, the electric 
charge keeping medium 32 of the electro-developing recording medium 30 is 
constituted as a memory type liquid crystal display, and thus the 
developed image can be held therein even if the output of the recording 
medium activating signal is stopped. 
At step 113, it is determined whether or not the quick return mirror 21 has 
moved to the initial position or down-position, and whether or not the 
opening area of the aperture 12a has returned to the initial area or 
fully-open area. Then, the control proceeds to step 114, in which the 
driving of the quick return mirror 21 and the aperture 12a are stopped, 
and thus the routine represented by the flowchart of FIG. 6 is ended. 
In the operation as mentioned above, the recording medium activating signal 
may be outputted just before the exposure is started, i.e., just before 
the shutter 22 is opened, if necessary. In this case, in the flow chart of 
FIG. 6, step 104 is positioned between steps 107 and 108. 
FIGS. 7 and 8 show a flowchart for explaining a scanning operation for 
optically sensing and reading the developed image held in the 
electro-developing recording medium 30. With reference to FIG. 5, and 
FIGS. 7 and 8, the scanning operation will now be explained below. 
At step 201, it is determined whether or not the scan start switch 16 has 
been made ON. If the scan start switch 16 has been turned out, a scanner 
drive command signal for executing the scanning operation is made ON 
(reference "S31" in FIG. 5), and is inputted to the system control 
circuit. 
At step 202, the shutter 22 is opened (reference "S32" in FIG. 5), and the 
control proceeds to step 203, in which the light source 42 is made ON 
(reference "S33" in FIG. 5). Then, at step 204, a scanner drive signal 
outputted from the system control circuit 20 to the scanner drive circuit 
46 is changed from the zero level to the positive level (reference "S34" 
in FIG. 5), so that the scan drive motor for moving the carriage member 52 
is driven in a forward direction due to the drive pulses outputted from 
the scanner drive circuit 46 thereto, whereby the carriage member 52 of 
the scanning mechanism 50 starts to move upward from the lower position or 
removal position, toward the scanning start position or image-reading 
start position (reference "S35" in FIG. 5). Subsequently, at step 205, a 
line sensor drive power source included in the line sensor drive circuit 
47 is made ON (reference "S36" in FIG. 5). 
At step 206, it is determined whether or not the carriage member 52 
carrying the light source 42 and the line sensor 44 has been moved to the 
image-reading start position. When the carriage member 52 reaches the 
image-reading start position, the control proceeds to step 207, in which 
the scanner drive signal outputted from the system control circuit 20 to 
the scanner drive circuit 46 is returned from the positive level to the 
zero level (reference "S37" in FIG. 5), and thus the output of the drive 
pulses from the scanner drive circuit 46 to the scan drive motor is 
interrupted to thereby stop the scan drive motor (reference "S38" in FIG. 
5), whereby the carriage member 52 carrying the light source 42 and the 
line sensor 44 is held at the image-reading start position. Note, the 
standing still of the carriage member 52 at the image-reading start 
position may be controlled by, for example, counting the driving pulses 
outputted from the scanner drive circuit 46 to the scan drive motor. 
At step 208, an exposure of the line sensor 44 is started by the 
illumination of the light source 42, and thus electric charge accumulation 
in the line sensor 44 is performed (reference "S39" in FIG. 5). Then, at 
step 209, it is determined whether or not a given time has elapsed or the 
electric charge accumulation in the line sensor 44 has been completed. 
When the electric charge accumulation in the line sensor 44 is completed, 
the control proceeds to step 210, in which a reading-scan of pixel signals 
from the line sensor 44 (i.e., a first horizontal-scanning line), is 
started by the line sensor drive circuit (reference "S40" in FIG. 5). 
At step 211, the scanner drive signal outputted from the system control 
circuit 20 to the scanner drive circuit 46 is changed from the zero level 
to the positive level (reference "S41" in FIG. 5), so that the scan drive 
motor is driven in the forward direction due to the drive pulses outputted 
from the scanner drive circuit 46 thereto. Thus the carriage member 52, 
and therefore, the light source 42 and the line sensor 44, are moved 
upward (reference "S42" in FIG. 5). 
During the movement of the carriage member 52, it is determined at step 212 
whether or not the reading-scan of pixel signals from the line sensor 44 
has been completed. If the completion of the reading-scan is confirmed, 
the control proceeds to step 213, in which the reading-scan of pixel 
signals from the line sensor 44 is stopped (reference "S43" in FIG. 5). 
Note that the completion of the reading-scan can be determined by, for 
example, counting reading-clock pulses outputted from the line sensor 
drive circuit 47 to drive the line sensor 44. 
At step 212, if the completion of the reading-scan is not confirmed, the 
control skips over step 213, and then the control proceeds to step 214, in 
which it is determined whether or not the carriage member 52, carrying the 
light source 42 and the line sensor 44, has been moved to a next 
image-reading position (corresponding to a position at which the pixel 
signals included in a subsequent horizontal scanning line are read). If 
the carriage member 52 has not reached the next image-reading position, 
the control returns to step 212, and the routine including steps 212, 213, 
and 214 is repeated until the line sensor 44 reaches the next 
image-reading position. 
At step 212, if the completion of the reading-scan is confirmed, the 
control proceeds to step 213, in which the reading-scan of pixel signals 
from the line sensor 44 is stopped. Then, the control proceeds to step 
214. 
At step 214, when it is confirmed that the carriage member 52 carrying the 
light source 42 and the line sensor 44 has reached the next image-reading 
position, the control proceeds from step 214 to step 215, in which the 
scanner drive signal outputted from the system control circuit 20 to the 
scanner drive circuit 46 is returned from the positive level to the zero 
level (reference "S44" in FIG. 5). Thus the output of the drive pulses 
from the scanner drive circuit 46 to the scan drive motor is interrupted 
to thereby stop the scan drive motor (reference "S45" in FIG. 5), whereby 
the carriage member 52 is held at the next image-reading position. 
Similarly, the standing still of the carriage member 52 at the next 
image-reading position can be controlled by counting the driving pulses 
outputted from the scanner drive circuit 46 to the scan drive motor. 
Then, at step 216, it is again determined whether or not the reading-scan 
of the single-line of pixel signals from the line sensor 44 has been 
completed. This is because the control may proceed from step 214 to step 
215 without having any access to step 213, i.e., because there may be a 
case where the reading-scan of the pixel signals from the line sensor 44 
is not yet completed even after the carriage member 52 reaches the next 
image-reading position. When the completion of the reading-scan is 
confirmed at step 216, the control proceeds to step 217, in which the 
operation for the reading-scan is stopped. 
At step 218, it is determined whether or not the whole of the developed 
image has been completely read, i.e., the reading-scans have been 
completed on all of the horizontal-scanning lines defined by intervals of 
the intermittent movements of the line sensor 44. This determination is 
made possible by, for example, counting the drive pulses outputted from 
the scanner drive circuit 46. If the whole of the developed image has not 
been completely read, the control returns to step 208. Namely, the routine 
including steps 208 to 218 is repeated until the reading-scans are 
completed on all of the horizontal-scanning lines. Note, in this first 
embodiment, all of the horizontal-scanning lines may be a number of about 
2,000. 
At step 218, when the whole of the developed image has been completely read 
(reference "S50" in FIG. 5), the control proceeds to step 219, in which 
the line sensor drive power source included in the line sensor drive 
circuit 47 is made OFF (reference "S51" in FIG. 5). Then, at step 220, the 
light source 42 is made OFF (reference "S52" in FIG. 5), and at step 221, 
the shutter 22 is closed (reference "S53" in FIG. 5). Subsequently, at 
step 222, the scanner drive signal outputted from the system control 
circuit 20 to the scanner drive circuit 46 is changed from the zero level 
to the negative level (reference "S54" in FIG. 5), so that the scan drive 
motor is driven in a reverse direction due to the drive pulses outputted 
from the scanner drive circuit 46 thereto, whereby the carriage member 52 
of the scanning mechanism 50 starts to move downward toward the lower 
position or removal position (reference "S55" in FIG. 5). 
At step 223, it is determined whether or not the carriage member 52 has 
been moved to the removal position. When the carriage member 52 reaches 
the removal position, the control proceeds to step 224, in which the 
scanner drive signal outputted from the system control circuit 20 to the 
scanner drive circuit 46 is returned from the negative level to the zero 
level (reference "S56" in FIG. 5). Thus the output of the drive pulses 
from the scanner drive circuit 46 to the scan drive motor is stopped, 
i.e., the scan drive motor is stopped (reference "S57" in FIG. 5), whereby 
the carriage member 52 is held at the removal position thereof. The 
standing still of the carriage member 52 at the removal position may be 
determined by detecting a part of the carriage member 52 with, for 
example, a photo-interrupter type detector (not shown). Thus, the routine 
of FIGS. 7 and 8 is ended. 
According to the present invention, the image reader or scanning mechanism 
50 can be compactly arranged because the linear light emitting surface of 
the light source 42 and the linear light receiving surface of the line 
sensor 44 are oriented in the same direction, and because the optical 
system 43, opposed thereto, is arranged such that the light beams emitted 
from the light source 42 are directed to the line sensor 44. If an image 
reader or scanning mechanism (50) is constituted by a light source (42), 
an image-forming lens (43a), and a line sensor (44), aligned with each 
other such that an electro-developing recording medium (30) is intervened 
between the light source (42) and the image-forming lens (43a), the 
arrangement of such an image reader (50) becomes bulkier, resulting in a 
bulkiness of the whole structure of the camera. 
Note that the electro-developing recording medium 30 is not restricted to 
the structure described above, and may be any other structure by which an 
image is electronically developed. 
In the embodiment as mentioned above, although the image reader or scanning 
mechanism 50 is moved with respect to the electro-developing recording 
medium 30, the latter may be movable with respect to the former such that 
a developed image of the electro-developing recording medium 30 can be 
scanned with the light source associated with the line sensor. 
The present invention is not restricted to a single-lens reflex camera 
described above, but it may be applied to a lens shutter camera. 
Note that, when the present invention is applied to a lens shutter camera, 
the shutter 22 need not be provided, as in the above described embodiment. 
A single lens, a micro-lens array, a rod lens array and so on, may be used 
for the scanner optical system 43. 
The line sensor 44 may be disposed in such a manner that light beams 
reflected by the electro-developing recording medium 30 are read or 
sensed. 
Finally, it will be understood by those skilled in the art that the 
foregoing description is of a preferred embodiment of the disclosed 
electronic still video camera, and that various changes and modifications 
may be made to the present invention without departing from the spirit and 
scope thereof. 
The present disclosure relates to subject matter contained in Japanese 
Patent Application No. 7-30128 (filed on Jan. 26, 1995), which is 
expressly incorporated herein, by reference, in its entirety.