JPH0242866A - Reader - Google Patents

Abstract

PURPOSE:To obtain a projected image to be correctly focused by moving a projecting lens based on a detecting signal detected by means of a reading part or an exclusive-use focus detecting sensor and executing the focusing of the projected image in a transmitted original. CONSTITUTION:For the focusing, a pattern 74 prepared to a film holder 70 is used, a contrast is judged from the detecting signal of a reading sensor 33, a projecting lens 46 is driven based on it, and the focusing is executed. For the pattern 74, a pattern 74a for a rough adjustment with a large pitch and a pattern 74b for a fine adjustment with a small pitch 4 are juxtaposed, and the projected image is read by the sensor 33. The read signal is given to a control part, the control part operates an MTF(Modulation Transfer Function) value, simultaneously, a driving signal for moving the projecting lens 46 to a position where it is made maximum is generated to a motor driving circuit, a motor 45 is driven, the lens 46 is moved, and the focusing is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a reading device for reading original documents in an image forming apparatus such as a copying machine, and more specifically to a reading device capable of reading photographic film.

[Prior art]

In recent years, digital copying machines that can store and process the image information of scanned originals as electrical signals have been put into practical use, making it easy to perform positive inversion from normal photographic film, that is, negative film. As a result, there is an increasing desire to obtain copies directly from photographic film. 2. Description of the Related Art Conventionally, there is a copying machine that obtains an enlarged copy from a small transparent original such as a photographic film, as disclosed in, for example, Japanese Patent Laid-Open No. 198439/1983.

This is done by additionally installing a projector, reflecting mirror, etc.
A film image is enlarged and projected onto a document table and read by a scanning optical system.

[Problem to be solved by the invention]

By the way, in the conventional example described above, the film image is enlarged and projected onto the document table, but if this projected image is not accurately focused on the reading section, the image cannot be read with high precision. Can not. For this reason, the operator moves the projection lens of the projector in the optical axis direction while looking at the projected image to adjust the focus, but this is time-consuming and is left to the operator's discretion.
There is a problem in that it is not always possible to focus accurately.

The present invention has been made in view of the above circumstances, and after a film or the like is loaded into a projector, the projected image is automatically and accurately focused without bothering the operator, and the image is enhanced. The purpose is to provide a reading device that can read accurately.

[Means to solve the problem]

A reading device according to the present invention is a reading device that uses a light source and a lens to read an image of a transparent original that is enlarged and projected onto a reading unit including a plurality of image pickup devices, and the reading device uses a light source and a lens to move the lens in an optical axis direction. control for driving the lens moving unit based on a difference in brightness signals between the moving unit and the image pickup device of the projected image in the reading unit so as to focus the projected image of the transparent original on the reading unit; and a control section that emits a signal, and the control section is characterized in that the control section issues the control signal based on a detection signal from a focus detection sensor provided near the reading section.

[Effect]

The control unit sends a control signal to the lens moving unit based on the difference in brightness and darkness signals between the imaging devices of the projected image detected by the reading unit or a focus detection sensor provided in the vicinity of the reading unit, or the focus detection signal. The projected image is focused on the reading section by emitting light and moving the lens in the optical axis direction.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on drawings showing embodiments thereof. FIG. 1 is a perspective view showing the internal structure of a reading device main body in a reading device according to the present invention (hereinafter referred to as the device of the present invention). The reading device main body 1 is provided with a document table glass 2 on its upper surface, and a pair of rails 5a and 5b are disposed on the inner bottom facing each other with their elongated direction being the width direction of the reading device main body 1. , 5b, a rectangular parallelepiped-shaped reading head 3 with its elongated direction perpendicular to the extending direction thereof is placed in a straddling state. The reading head section 3 has a plurality of solid-state image elements (CCDs) inside thereof, with its entrance side facing upward, as shown in the longitudinal cross-sectional view of FIG.
) are arranged in a row, and are equipped with a reading lens 32 made of, for example, a convergent Rondo lens, a light source 31, etc., which face the reading sensor 33 arranged in a row, and these have their elongated directions facing the reading head section 3, respectively. When reading a normal original, that is, an opaque original, the light source 31 is turned on, and the reflected light image of the opaque original placed on the original platen 2 illuminates the reading lens 32. When the light enters the reading sensor 33 through the sensor, the reading sensor 33 main-scans the document, and pulleys 4a and 4b provided on the rails 5a and 5b to be rotationally driven by the motor 4C, respectively, and the The reading section 3 is moved along the rails 5a, 5b in the width direction of the reading device main body 1, that is, in the left-right direction, by the wires 7a, 7b, thereby performing sub-scanning of the document.

FIG. 2 is a longitudinal cross-sectional view from the front side showing how the reading device main body 1 is equipped with a projector, a mirror, etc. when enlarging and reading a small transparent original such as a photographic film according to the main part of the present invention. . First, in this embodiment, the entire image of one frame of the film to be read is enlarged and projected onto the document table as in the conventional case, and the projected image is obtained by moving the reading unit as in the case of an opaque document. The reading unit is kept stationary, and the projection area for the reading unit is changed by moving the film that is enlarged and projected, thereby reading and scanning the entire image. A film moving mechanism is provided for this purpose, and it goes without saying that the film moving operation and the signal processing of the reading section are performed in synchronization.

The projector 6 is arranged substantially horizontally at a position higher than the upper surface of the right side edge of the reading device main body 1, and its projected light is directed to a mirror 9, which will be described later, provided on the left side of the document platen glass 2. irradiated. The projector 6 is attached to the reader main body 1 as shown in the right side view of FIG.
A guide member 55 that slides in the depth direction on a slide rail 54 mounted on the right side of the reader body 1 with its length direction facing the depth direction of the reader body 1 has an axis extending in the depth direction of the reader body 1 at the top of the guide member 55 . This is achieved by pivoting the center of gravity of the lower part of the projector 6 by the supported shaft 53, thereby making the projector 6 rotatable around the shaft 53. A stopper 52 is disposed between the rear end of the projector 6 and the lower part of the guide member 55, and is formed by connecting two members of approximately the same size so that they can be bent freely in the middle. As shown in FIG. 3, by extending each member of the stopper 52, the projector 6 is held in a state in which the light emitting part is directed horizontally and the film can be projected and moved. is rotated 90 degrees about the shaft 53 and held in a vertical state with the light projecting section facing directly upward, and in this state the slide rail 54 is rotated about the shaft 53 as shown in FIG.
The projector 6 can be retracted together with the guide member 55 to the rear side of the reading device main body 1, and as a result, the operation of the operator is not hindered during normal reading when a document is placed on the document table 2. . In other words, the slide rail 54 is provided to evacuate the projector 6.
When projecting a film, the projector 6 is fixed at a predetermined position approximately midway in the depth direction of the main body l of the reading device.

The projector 6 is equipped with a light source 40 on its rear side (right side in FIG. 2), and in order from the light source 40 side to the front are condenser lenses 42a and 42b, and a cylindrical lens 4.
3, 44, a film holder 70 for holding a film to be projected; A projection lens 46 and an image rotation prism 47 are arranged, and a reflecting mirror 41 and a cooling fan 50 are arranged behind the light source 40, respectively.

The film holder 70 is designed to hold long pieces of film that are usually cut into lengths of several frames for storage, and are both transparent as shown in the external perspective view of FIG. Thin plate-shaped holding plate 70a and mounting plate 70 made of material
The one side edges of b are hinged together so that they can be opened and closed tightly, and the mounting plate 70b has a recess 71 that is approximately equal in thickness and width to the film for placing and positioning the film. and a plurality of dowels 72 are formed, and the holding plate 70a has a plurality of protrusions 73 fitted into the dowels 72 and a linear pattern 74, 74 for focusing by AP (autofocus) described later. They are formed near both longitudinal ends of the presser plate 70a, with the longitudinal direction thereof set as the width direction of the presser plate 70a. In other words, the film piece is placed on the mounting plate 7.
It is placed in the recess 71 of 0b, and the holding plate 70a and the placing plate 7
It is held in a sandwiched state by bringing it into close contact with 0b.

This suppresses warping of the film, provides uniform image quality when projected, and facilitates handling by the operator.

The film holder 70 is incorporated into the projector 6 so as to be movable in the horizontal direction, that is, in the direction perpendicular to the plane of the paper in FIG. 6th
The figure shows a longitudinal cross-sectional view of the film scanning unit that drives the projector 6, viewed from the front side, that is, from the projection lens 46 side.

The film scanning unit 80 is provided with a flat, vertically elongated guide hole 85 through which the film holder 70 is inserted, with the width direction of the film surface being the vertical direction, and passing through the projector 6 in the left-right direction. Film holder guides 84 for guiding the insertion of the film holder 70 are formed at four locations at the upper and lower parts near the upper and lower parts.
Alternatively, a plurality of free rollers 81 are provided between the lower portions to sandwich and support the film holder 70 from above and below. And between the free rollers 81 on the lower side is the motor 8.
A driving roller 82 is provided which is rotated by the film holder 3. The driving roller 82 is retracted when the film holder 70 is inserted or removed, and comes into pressure contact when the film holder 70 is inserted. With this configuration, the film holder 70 is moved in the direction of the arrow by the rotation of the drive roller 82 to scan the film image and also to select other frames on the same film. It is also possible to return the film holder 70 in the opposite direction by rotating the motor 83 in the opposite direction, thereby making it possible to cope with multiple scans of full-color images. 70
Since scanning is performed by moving the , highly accurate and stable scanning can be performed without uneven scanning.

The projection lens 46 of the projector 6 is reciprocated in the longitudinal direction of the optical axis by the motor 45, which is the lens moving section, and thereby the projected light image is focused as described later.

On the left side of the document platen glass 2 on the upper surface of the reading device main body 1, there is a long side having a depth approximately equal to the depth of the platen glass 2.
A rectangular film reading opening 8 whose short side in the width direction is slightly wider than the width of the reading lens 32 in the sub-scanning direction is formed parallel to the document table glass 2. A Fresnel lens 10 having a screen surface on the lower surface is attached to the lens to seal it. Further, a mirror 1tll is attached to the opening 8, the negative side edge of which is pivotally supported in the depth direction of the reading device main body l, and which can be opened to the left side of the opening 8. The mirror lid 11 has a mirror 9 of approximately the same shape and size as the Fresnel lens 10 attached to the lower surface thereof, and can be held in a state tilted at an angle of about 45 degrees to the upper right to prevent irradiation from the projector 6. The projected light image is reflected onto a Fresnel lens 10 vertically downward, and when the film is not read by this projection, the Fresnel lens 10 and the opening 8 are sealed. , similar to the projector 6, does not interfere with the operator's movements during normal reading;
It is possible to avoid the trouble of placing and removing a reflecting mirror jig on the document table as in the conventional case, and since the mirror lid 11 is installed so that the longitudinal direction is perpendicular to the optical axis, the light There is no deviation from the axis, and no distortion occurs in the projected image.

The reading head section 3 is moved below the opening 8, and the reading lens 32 is placed on the screen surface of the lower surface of the Fresnel lens 10.
It is fixed at a position facing the incident side of the film, and this position becomes the film reading position of the reading head section 3. This film reading position is not particularly limited to this position, but if it is located below the document table glass 2, it is necessary to place a reflecting mirror jig on the document table as in the conventional case. There is also the disadvantage that the amount of light for reading is lost due to the undesirable and unnecessary glass plate. Therefore, the above-mentioned problems can be solved by providing a dedicated opening and setting the reading position below the opening.

Now, the optical path of the projected light image by the projector 6, mirror 9, and Fresnel lens 10 configured as above will be explained.

FIGS. 7 and 8 are a plan view and a side view showing the optical path. The illumination system by the projector 6 constitutes a Koehler illumination system, and by creating an image of the light source 40 in the pupil of the projection lens 46, a filament image of the light source 40 is not generated on the screen surface on the lower surface of the Fresnel lens 10. , all the light beams directed from the light source 40 to the projection lens 46 can be used.

First, the illumination light from the light source 40 is efficiently utilized by the light rays traveling in the opposite direction to the film 75 being condensed by the reflection m41 and directed toward the light source 40, and guided to the condenser lenses 42a and 42b. The light beams condensed by the condenser lenses 42a and 42b are converged into a vertically long slit shape through cylindrical lenses 43 and 44 that change the aspect ratio, and are transmitted through the film 75 to the projection lens 46. An image of light 1a4o is formed in the pupil in a vertical direction. In other words, the cylindrical lenses 43 and 44 are provided so as to illuminate one frame image of the film 75 in the form of a vertically long slit over the entire length of the film 75 in the width direction in a part of the length direction. After this vertically long optical image is emitted from the projection lens 46, the image rotating prism 4
The image is rotated by 90 degrees by the mirror 7 and enlarged to form a horizontally long image, which is reflected by the mirror 9 and reaches the Fresnel lens 10. And the diffusing light beam is the Fresnel lens 10
The optical image of the elongated film is enlarged and projected onto the lower screen surface, with its longitudinal direction aligned with the depth direction of the reader main body 1.

The reason why the film 75 is illuminated in a slit shape is as follows. In other words, in a configuration in which scanning is performed by moving the film 75 while keeping the reading head section 3 stationary, it is not necessary to illuminate the film so as to project the entire image of one frame. In this embodiment, it is only necessary to illuminate in the direction corresponding to the main scanning direction, that is, in the direction perpendicular to the set film surface, and almost no width in the horizontal direction is required. Therefore, by converging the illumination light from the light source 40 into a slit shape, the illuminance of the image on the screen surface can be increased compared to the conventional illuminance when the entire image is projected.
Even if the luminous intensity of the light source 40 is lower than the luminous intensity of the light source in the case of full projection, it is possible to ensure sufficient conventional illuminance that does not interfere with reading, so the power consumption of the light source 40, that is, the illumination system, can be suppressed. In addition, in a conventional overall projected image, there is a difference in illuminance between the center and the periphery due to uneven light intensity of the light source, so the reading sensor performs corrected reading of the illumination light in the main scanning and sub-scanning directions respectively before projection. However, in the present invention, by reading the reading sensor stationary, the film is moved in a direction perpendicular to the optical axis while the optical axis of the illumination light is always projected onto the reading sensor. Therefore, even if the film is moved and the projection area changes, the illuminance at the middle of the film's slit-shaped projected image always corresponds to the illuminance at the center of the conventional overall projected image. There is no need to perform correction in the movement direction, that is, in the sub-scanning direction, and it is sufficient to perform correction only in the main-scanning direction. Furthermore, since the projected image is also slit-shaped, it is reflected,
There is no need to use large projecting mirrors, Fresnel lenses, and screen surfaces as in the past, making it possible to reduce the size and the installation height on the document table.

In this embodiment, a cylindrical lens is used to converge the illumination light into a slit shape, but a linear Fresnel lens may be used instead.

Next, the focusing of the projected image by the AP using the motor 45, which is the main part of the present invention, will be explained. FIG. 9 is a block diagram showing the configuration of the control system, and the output of the reading sensor 33 is input via the signal processing circuit 15 to an input port of a control section 16 using a microprocessor. A motor drive circuit 17 is connected to the output port of the control section 16, and the motor 45 is connected to the motor drive circuit 17. In this focusing, the contrast is determined from the detection signal of the reading sensor 33 using the pattern 74 formed on the film holder 70, and the projection lens 46 is driven and focused based on the contrast. The pattern 74 has a coarse adjustment pattern 74a with a large pitch and a fine adjustment pattern 74b with a small pitch arranged side by side in the width direction of the film holder 70. , since the directions in which these patterns are arranged in parallel, that is, the longitudinal direction of the pattern 74, match, substantially the entire pattern 74 is projected at the same time, and the reading sensor 33
The projected image is read by. This read signal is given to the control unit 16, and the control unit 16 controls the MTF (Mo
durationTransferFunction
) value and sends a drive signal to the motor drive circuit 1 to move the projection lens 46 to the position where the value is maximum.
Send to 7. In this case, first, the rough adjustment pattern 74
Read the projected image a, move the projection lens 46 relatively largely to the position where the MTF value is maximum, then read the pattern 74b for fine adjustment, and move the projection lens 46
Similarly, set it to the position where its MTF value is maximum while slightly moving it. In other words, the fact that the MTF value is maximized means that in the plurality of solid-state image sensors arranged in a row in the reading sensor 33, the difference in brightness between adjacent elements to recognize the white and black of the pattern, that is, the contrast is maximized. This means that the image is not blurred and is accurately focused, so you can judge that it is in focus.

Focusing using such a pattern 74 is performed before reading the film image, but focusing is performed in parallel with reading the film image using a pattern 76 as shown in the external perspective view of the film holder in FIG. It is also possible to do so. This pattern 76 has a plurality of lines approximately equal to the length of the film holder arranged in parallel in the width direction of the film holder. It is provided at a position that will be on the upper or lower side of the film piece when In other words, since the pattern 76 is always projected at a position closer to the front or further back on the screen surface together with the image of the film being moved, the part of the reading sensor 33 corresponding to that position is used as described above. At the same time as the focusing is performed based on the contrast, other parts of the reading sensor 33 read the original film image.

Note that the above-mentioned focusing using the 8F is performed using the reading sensor 33.
This is done using the detection signal of A.
It is also possible to provide a dedicated sensor for F and use its detection signal (the configuration of which will be explained next. FIG. 11 shows an example of an AP sensor provided on the Fresnel lens 10, This is a vertical cross-sectional view of the front side of the device main body 1, and the AF sensor 90, which is the focus detection sensor, has sensors St and Sg formed by using a CCD line sensor of an appropriate length on the lower part thereof, and a sensor that reads the longitudinal direction of these sensors. Fresnel lenses 1 are aligned in the longitudinal direction of 33 and spaced apart from each other by an appropriate length.
A beam splinter 91 is disposed above the projector 6 to guide the projection light beam from the projector 6 to the sensors St and Sz with different optical path lengths. be. The beam splitter 91 is L, where the optical path length to the screen surface on the lower surface of the Fresnel lens 10, that is, the surface to be focused, is L1, the optical path length to sensor SI is LI, and the optical path length to sensor S2 is L.
! It is defined that <L<Ll and -L=LL.

In other words, the sensors SI and S2 are provided at equal distances from the screen surface and at positions corresponding to the rear and front sides, respectively, and as a result, the projected images of the film holder pattern, etc. The contrast output signal value of each sensor that reads is not focused on the screen surface, for example, in the so-called front bin (or back focus) state where the focus is in front (or behind) the screen surface In this case, the output of sensor St (or Sl) is higher than the output of Sl (or St), and when the focus is on the screen surface, the output values are equal, and this relationship can be expressed as follows: It is used to perform AP.

FIG. 12 is a flowchart showing the control procedure, in which the output value of sensor Sl is set to S5, and the output value of sensor St is set to 8.
2. First, in step S1, St 10s,
is zero, and if it is zero, that is, if it is extremely front focused or rear focused, the projection lens is reciprocated by a large amount so that an output value is generated (step S2). .

Once the output is obtained, compare it and if s, > s, then
In other words, when in the rear pin state, move toward the front bin or S
, <Sfi, that is, in the front focus state, the projection lens is moved by a predetermined amount toward the rear bin (
Steps S3 to S5). As a result, when St = st, it is detected that the screen is in focus, and the AP ends.

Note that the 1 sensor 90 is removed from the Fresnel lens 10 when reading a film image after the AP is completed, but it may be configured to be automatically installed or evacuated in conjunction with the AP operation. In addition, the AF sensor is always provided at a position away from the Fresnel lens 10, such as between the opening 8 and the document table glass 2, and the sensor is set by changing the inclination angle of the mirror lid 11 only during AP. A configuration may also be adopted in which a measuring operation is performed by forming an optical path up to.

Furthermore, in the focusing by the series of APs mentioned above,
The configuration uses a projected image of a pattern formed on a film holder made of a transparent material, but this is not particularly limited except when performing 8F in parallel with reading the film image, and the projection image of the film is used. It is also possible to judge the contrast from the image, and in that case, as shown in the external perspective view of Figure 13, there are two slopes that hold the film piece in place, each with a shape corresponding to the size of each frame of the film piece. A film holder having a plurality of openings 77, 77, . . . arranged side by side may be used, and of course this film holder need not be transparent.

Next, an example of the film image reading operation performed by the apparatus of the present invention constructed as described above will be explained. First, as shown in FIG. 2, the mirror lid 11 is opened and set at a predetermined angle, and the reading head 3 having the reading sensor 33, which has been read with correction in the main scanning direction, is placed below the opening 8. The projector 6 is moved to the reading position, and the projector 6 is placed in a state where it can project. Then, the film holder 70 holding the film piece to be read is installed in the film scanning section 80 of the projector 6, the light source 40 is turned on, the pattern 74 of the film holder is projected onto the screen surface, and this projected image is used to perform the F operation. Focus by doing. When the camera is in focus, the film holder 70 is moved to project the reading start position of a desired frame of the film piece, and read preparation is completed.

At this point, the vicinity of one end of the film piece in the longitudinal direction of one frame image is enlarged and projected in a slit shape, and after that, the reading signal of the reading sensor 33 is processed,
The entire enlarged image of one frame is read by synchronizing the movement of the film holder 70 by the motor 83 of the film scanning section 80, that is, the change of the projection area. Note that during this reading, the light source 31 of the reading head section 3
There is no need to turn on the light.

In this embodiment, the film holder is moved in the horizontal direction when reading, but it may be moved in the vertical direction instead. In that case, the longitudinal direction of the slit illumination area relative to the film is in the horizontal direction. Therefore, there is no need to rotate the projected light image by 90 degrees, and the image rotation prism can be omitted. Furthermore, in that case, the film holder is arranged in the projector with its longitudinal direction being the vertical direction, but if it is not desired to protrude the film holder in the vertical direction of the projector due to space considerations, the external perspective view shown in Fig. 14 may be used. A film scanning mechanism as shown in the figure may also be provided. This includes a film holder support member 80a that supports the film holder 70 so that a film image can be selected with the longitudinal direction of the film holder 70 in the horizontal direction, and a guide shaft 88a that supports the support member 80a vertically.
, 88b in the vertical direction. This movement is performed by, for example, a pulley 87. which is rotationally driven by a motor 83a. This may be done using the pulley 86 and the wire 89 stretched between the pulleys 86 and the like. In other words, the film holder 70 is moved and scanned in the vertical direction with its longitudinal direction set in the horizontal direction.

〔effect〕

As described above, in the reading device according to the present invention, focusing of a projected image on a small transparent original such as a film is carried out as follows:
This is performed by moving the projection lens in the optical axis direction by a motor or the like based on a detection signal detected by a reading unit that reads a projected image or a dedicated focus detection sensor. As a result, there is no need for the operator to adjust the focus himself/herself, and an accurately focused projected image can be obtained. As a result, highly accurate reading can be performed, and the present invention has excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the internal structure of the main body of a reading device according to the present invention, FIG. 2 is a front vertical sectional view when a transparent original is enlarged and projected, and FIG. 3 is a right side view thereof. Fig. 4 is a right side view showing the projector in a retracted state, Fig. 5 is an external perspective view of the film holder, Fig. 6 is a vertical sectional view of the film scanning unit, and Figs. 7 and 8 are plan views showing the projection optical path. 9 is a block diagram of the control system for focusing the projected image, FIG. 10 is an external perspective view showing the second embodiment of the film holder, and FIG. 11 is a diagram of the AP sensor. FIG. 12 is a flow chart showing the AP control procedure, FIG. 13 is an external perspective view showing a third embodiment of the film holder, and FIG. 14 is another embodiment of the film scanning unit. FIG. 1...Reading device body 3...Reading head section 6...
・Projector 9...Mirror 10...Fresnel lens 16...Control unit 33...Reading sensor 43
, 44... Cylindrical lens 45... Projection lens 47... Image rotation prism 70... Film holder 80... Film scanning section 90... To F sensor patent

Claims (1)

[Claims] 1. In a reading device that uses a light source and a lens to read an image of a transparent original that is enlarged and projected onto a reading section that includes a plurality of image pickup devices, the lens moves the lens in the optical axis direction. a moving unit; and control for driving the lens moving unit based on a difference in brightness signals between the image pickup devices of the projected image in the reading unit so as to focus the projected image of the transparent original on the reading unit. A reading device comprising: a control section that emits a signal. 2. The reading device according to claim 1, wherein the control section issues the control signal based on a detection signal from a focus detection sensor provided near the reading section.