JPS59225670A - Picture processing device - Google Patents

Abstract

PURPOSE:To obtain the device having a high detecting and reading capability by supporting the mirror surface while reinforcing it with a rigid member made of a synthetic resin so as not to cause distortion relating to a picture processing device having an original detector. CONSTITUTION:An original placing pate glass 2 placing an original to be read and the original covering member 3 for freely opening and closing where the original covering face of the mirror surface to cover the said original placed on the glass 2 is supported by the rigid member are fitted to the upper face of a picture reading section 1. A mirror surface 3c of a mirror surface sheet 3b whose mirror surface 3c is formed by applying aluminum vapor deposition to one side of a transparent polyester film is bonded on a rigid board 3d made of the synthetic resin or the like and hardly deformed and further, the board 3d is supported by a cover 3f made of a synthetic resin or the like having legs 3e for preventing deformation. Through the constitution above, no local deformation is caused to the mirror surface 3c by the rigidity of the cover 3f and the board 3d.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image processing device, in particular, an image processing device that detects various optical information such as the presence or absence of a document to be read or its size using an optical sensor;
The present invention relates to an image processing apparatus having an original f+P detection device that performs electrical processing based on this.

Generally, document detection devices such as those described above are used for various purposes. For example, there is a method in which the original to be read is transported across the optical path of an image projection optical system to scan the original using an original transport device using a belt or rollers, or a method in which the original is scanned by transporting the original to be read across the optical path of an image projection optical system, or In an image processing apparatus that projects an image after transporting and positioning the document onto the document support surface, it is determined whether the document is in seven predetermined positions in the optical path or on the document support surface; The document detecting device described above is used to detect whether a position has been reached.

In addition, by detecting the document size using the document detection device, the recording paper size can be selected, and the projection magnification of one document can be automatically changed by comparing the original size and the recording paper size. In addition, an image forming device that reads the original image with an image sensor, converts it into an electrical signal, and writes the image on a photosensitive surface or recording paper based on this signal is used to print the original image and print the original size. Processing such as writing an image signal only in the area corresponding to the area is also performed.

Therefore, the method for detecting the presence or absence of a document or its size is an optical method, in which light is irradiated onto the area where the document is placed, and an optical sensor receives the reflected light from the surface of the document image. The method of extracting an output signal corresponding to the incident intensity and determining the presence or absence of a document or the document size is the simplest and most practical.

In this case, it is common to irradiate the document placement area with light, both when detecting the presence or absence of a document or the size of the document, and when projecting a document image onto an electrophotographic photoreceptor or an image sensor. Therefore, in this area, the document should be placed in close contact with the document placement surface.
Further, in order to prevent the irradiated light from the original from leaking to the outside, it is common to provide a cover for covering the original on the back side of the original, that is, an original cover member.

Therefore, conventionally, when the size of the document covered by the document cover member is small, a portion of the document cover surface of the document cover member facing the back side of the document, that is, a part of the document cover surface that is outside the size of the document, has been used. In some cases, the covering surface of the original in the area may also be recorded as an image, so that part may be recorded as a white image 1.
In order to record the image as an image, the cover surface of the document is made white.

However, in the above case, if the background color of the original is white like the original covering surface, the light reflected from the image plane of the original and the light reflected from the original covering surface of the original covering member are as follows. Since the two light beams are detected by the optical sensor at almost the same level, it is extremely difficult to determine the presence or absence of a document or the size of the document from the difference in these reflected lights.

Therefore, the cover surface of the document may be made black, or
It has also been proposed to open the document cover member so as not to cover the back surface of the document when the presence or absence and size of the document cannot be detected. In this way, the reflected light from the area protruding from the original image surface will not enter the optical sensor, so a clear difference will occur in the light level, and the presence or absence of the original and its size can be determined.

However, in this case, the following problem occurs.

Generally, when an original image is projected onto a photoreceptor or read by an image sensor, the original is irradiated with light and the reflected light is imaged on the photoreceptor or image sensor via an optical system. At this time, part of the light irradiated onto the original is diffusely reflected on the surface of the original, and the other part is transmitted through the original and exits from the back surface of the original.

The ratio of the reflected light to the transmitted light varies depending on the quality, thickness, etc. of the original. If there is another paper behind the original (for example, in the case of a book) or if there is a document cover member with a white document cover surface, the light transmitted through the original will be absorbed by the other paper or cover. It is reflected by the surface of the surface, a part of it passes through the document again, and is projected onto the photoreceptor or image sensor via the optical system,
Photoreceptor exposure or reading ((contributes). Therefore, in general image forming or processing equipment, the white color of the original is added to the level of light that passes through the original and returns like a sheet. However, as mentioned above, if you make the document cover black or open the document cover to detect the document, the light that passes through the document will be absorbed by the black document cover. The light will not be used for exposing the photoconductor or for reading as it will be dissipated into the air.Therefore, in the above case, if you use a document cover member with a white document cover surface, In comparison, the light intensity level for the white color of the document will be lowered.For example, in the case of a document made of high-quality paper that is normally used for general office work, the amount of light transmitted through the source flj'6 and returned to the original surface will be lower. ℃ and a lot of light, the background of the recorded image may be considerably foggy.Also, in the case of originals made of tracing paper used for drawings, more light returns than the above-mentioned high-quality paper. As a result, the background of the recorded image becomes black.As a result, it becomes almost impossible to distinguish between the document information and the background, resulting in many practical difficulties.

A method proposed for this purpose is to color the surface of the original with a color to which the photoconductor or image sensor has a very high color sensitivity (i.e., a color that would be judged as white), and then to Some attempts are made to determine the presence or absence of a document using an optical sensor that has low color sensitivity and is separate from the image sensing element. Then, for the optical sensor, the color of the document cover surface is
It appears darker compared to the white color of the manuscript, so it becomes clear whether there is a difference between the two. However, the color of the document background is not necessarily white, and there are many cases of colored backgrounds, and in such cases, the above-mentioned means cannot provide correspondence. Further, such a means has the disadvantage that it cannot be used in an apparatus in which an optical sensor for detecting the presence or absence of a document and its size also functions as an image sensor that reads the document image and converts it into an electrical signal.

Therefore, it has been proposed that the document cover surface is made of a mirror surface that specularly reflects light. This is because in areas where there is no document, the light from the light source is not diffusely reflected and is directly reflected specularly on the m32 surface, so most of the light is incident on the optical sensor installed at a position offset from the direction of reflection. First of all, the above area is detected as black. On the other hand, in the case of an original made of semi-transparent paper such as tracing paper, the light that passes through it is reflected on the mirror surface without being diffused to the outside, and then enters from the back side of the original, so the incident light is diffusely reflected and enters the optical sensor,
The area where the document exists is detected as white. In this way, making the document cover surface a mirror surface compensates for the above-mentioned drawbacks, but the following problems arise.

That is, since the original covering surface is supported only by an elastic member such as a sponge, as is usually done, the distortion of the original covering surface has an adverse effect. A specific example is shown in FIG. 7(a). Here, for example, a three-dimensional object such as a thick book 40 is used as a manuscript.
When pressed with the document covering member 3 whose surface 3a is a mirror surface, distortion occurs in the portion indicated by L9M in the circle. Then, as typically shown in Figure 7(b), the light from the light source is reflected by the distorted mirror surface, and the reflected light travels in the direction it should originally travel (as indicated by the two-dot chain arrow). (shown) and may end up entering the left side of the optical sensor 2. In this case, the area where the document does not exist is also detected as white, making it difficult to distinguish between the document surface and the document cover surface 3-a, and the size and position of the document cannot be detected correctly (i.e.,
Distortion of the mirror surface is a major cause of equipment malfunction.

The present invention has been made to solve the above-mentioned problems, and includes a document cover member having a mirror surface on the side that covers the document to be read, a light source for mainly irradiating the image surface of the document, and the light source. an image sensor that detects the reflected light of the document and converts it into an electrical signal, and a document detection device that detects the position, size, etc. of the document on the document table based on the signal, and the mirror surface is prevented from being distorted. It is an object of the present invention to provide an image processing device with high detection and reading ability by reinforcing and supporting this on the side of a hard part such as a synthetic resin so as to prevent this from occurring.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic diagram of an image processing apparatus to which the document cover side, which is a feature of the present invention, is applied. The image reading section has a document table glass plate on the top surface for placing the original to be read, and a mirror surface to cover the document placed thereon. A document cover member 3 that can be opened and closed and whose document cover surface is supported by a rigid plate is attached to the document cover member 3.
Ru. Furthermore, inside the image reading unit, there is a light source that irradiates light onto the image surface of the document while moving in the sub-scanning direction shown by the arrow, and a light source that reflects the light emitted from the light source on the image surface, etc. A solid-state image pickup device is provided which receives the light through the left mirror 7 and the lens g and converts it into an electrical signal.

The image recording section 10 also includes a semiconductor laser/image reading section/a semiconductor laser which emits a laser beam according to an image signal received by the image reading section/
/ and a rotating polygon mirror /2 which scans and exposes the surface of the photoreceptor by changing the traveling direction of the laser beam while rotating, and the laser beam reflected by the rotating polygon mirror /2 is reflected by the mirror /2.
3 onto the photoreceptor drum 11, and is transferred onto a recording paper through various known electrophotographic processes to be visualized.

Note that an unillustrated original detection device is provided between the solid-state image sensor and the semiconductor laser //, and an unillustrated document detector 1'I
The document detecting device detects the number 413 obtained by pre-scanning the image surface and the document cover surface with the light source by the i'l Qj circuit, and detects the presence, size, or position of the document. After detecting the size or position of the recording paper and selecting the projection magnification based on the information obtained from the pre-scan, a main scan is performed to read the original image report and record it.

FIG. 3 is a cross-sectional perspective view showing a part of an embodiment of the document cover member 3, which is a feature of the present invention. This involves bonding a mirror sheet 3b, which is formed by vapor-depositing aluminum on one side of a transparent Borien ter film to form a mirror surface 3C, to a hard temporary material 3d made of synthetic resin or the like that does not easily deform, using the mirror surface 3C.
Further, the plate 3d is supported by a cover 3f made of synthetic resin or the like and having legs 3e for preventing deformation. With this configuration, the rigidity of the cover 3f and the plate 3d makes it possible to maintain the mirror surface 3C.
No local deformation occurs.

Therefore, in an image processing apparatus as shown in the α' loss diagram using the document covering member 3 as described above, light from the light source is reflected by the mirrored document covering surface 3a or the document image surface, and The process up to detection by the image sensor wa will be explained based on FIGS. S and 3.

FIG. S shows the principle of light reflection in the region where the document cover member 3 covers the document 2o. A portion of the light emitted from the light source is diffusely reflected on the document image surface 20a to become a light ray A, and the rest is transmitted through the interior of the document 20. Since the document cover surface 3a is a mirror 17ii and no distortion occurs in the transmitted light,
The reflected light is almost reflected from that surface, and the reflected light passes through the inside of the document 20 again, and is diffusely reflected when it exits from the document image surface, 20a, and part of it becomes light ray B. The light beams A and B are received together by the solid-state image sensor 7 via a mirror or lens (not shown). Here, if the document 20 is semitransparent paper such as tracing paper, and the top surface of the document is black as in the conventional example described above, light will be absorbed by that surface (a solid-state image sensor However, in the present invention, the document covering surface is mirror-finished and local distortion is eliminated.
By adding light ray B to light ray A, a sufficient amount of light is obtained, and the color is detected as a level closer to white.
The background of the recorded image will not turn into a black spot.

FIG. 4 shows the principle of light reflection in an area below the document cover member 3 where no document exists. In this case, even if the original is a three-dimensional object such as a book, local distortion will not occur, and the light emitted from the light source will be directed to the flat original covering surface 3a.
Since the light is reflected almost specularly, there is no light that is reflected due to distortion and reaches the solid-state image sensor 9 as shown in FIG.

Then, it will be detected as a level close to black.

Therefore, for the reasons shown in FIGS. 5 and 6 above,
For example, as shown in FIG. 7, when a document 20 having a width W is placed on the upper surface of the document table glass unit and pre-scanning is performed with the document covering member 3 covering it from above, the solid-state image sensor 9 The signals received by the scanner and detected by a document detecting device (not shown) are as shown in FIG. In other words, as shown in FIG. 3(a), the signal obtained by main scanning along line C detects the portion of the width W of the original 20 at almost a white level, except for the portion where the image is drawn. The peripheral portion of the document 20 has a mirror surface and is therefore detected as a black level.

Further, all the signals obtained by the main scanning along the D line where the original document 20 does not exist are detected as a black level as shown in FIG. 3(b).

As described above, since the reflected light from the original image surface ΩOa or the original cover surface 3a in FIG. S is detected,
Unlike the conventional example described above, since the original W64W surface 3a is made white, there is no problem that it becomes difficult to distinguish between the base of the original and the color of the original covering surface, and the surroundings of the original of a three-dimensional object such as a book do not arise. There is no abnormal reflection of light due to distortion, and the boundary of the document 20 can be clearly distinguished between the white level and the black level and detected. Therefore, as described in detail later, this figure “
The size and position of the document 20 can be determined by detecting the edge of the document 20 where the black level signal changes to the white level signal during the scanning process using the document detecting device shown in FIG.

FIG. 9 is an explanatory diagram showing the positional relationship when the original cover surface 3a is made smaller than the original placement surface of the original platen glass a.Depending on the device, the original size and position are detected, When recording an image (image), it is also possible to prevent the image (image) from appearing in parts other than the original, so the gap The document cover surface 3a is lower than the surface of the stand glass unit.
can be made smaller. In this way, in the case of a thin original, the peripheral part of the original cover surface 3a will not ride on the original abutting reference name plate or size indication name plate installed on the original table glass, and the area between the original and the original cover surface 3a will be prevented. The document can be held down sufficiently without creating any gaps.

In addition, when using a three-dimensional document such as a book, as mentioned above, the black surrounding the document image surface can be prevented from being recorded as an image, so there is no need to intentionally bring the document cover surface into close contact with the document. , floating is not a problem as long as the mirror surface is not distorted.

FIG. 9 is a sectional view showing another embodiment of the document cover member 3, which is a feature of the present invention. This includes, for example, a cover 3f made of synthetic resin or the like, an elastic member 3g such as a sponge, a hard plate 3d made of synthetic resin or the like that does not easily deform, and a mirror sheet 3b made of a transparent polyester film or the like with a mirror surface formed on one side.
These are successively stacked and glued together. In this case, since the hard plate 3d is sandwiched between the mirror surface and the elastic member 3g, the mirror surface is prevented from being distorted even when covering a three-dimensional document, and the document is flexible. can be held down. In addition, if the mirror sheet 3b is a plate made of metal or a transparent synthetic resin plated with resin to prevent deformation, the plate 3d
may be removed.

However, if a mirror surface is formed on the outermost surface, the corrugated sheet does not need to be transparent.

FIG. 70 is a cross-sectional view showing still another embodiment of the original cover member (3) which is a feature of the present invention. Between,
Elastic member 3 having a thickness and hardness that does not cause local deformation
It is sandwiched with g. In this way, even when the document cover member 3 is strongly closed on the document table glass, the damping effect makes it difficult to generate contact noise.

In Figure 1, a transparent elastic member 3h is used in place of the elastic member assembly 3g in Fig. 70, and this is attached to the lower surface of the mirror sheet 3b. In this way, the 70th
A larger damping effect can be obtained than in the case shown in the figure.

Next, the document detecting means used during pre-scanning as described above,
In particular, the means for detecting the document position will be described below.

1 and 2 show a state in which an original 20 is placed on the original platen glass λ of the image reading section. Basically, the placement position is fixed, but it can also be placed diagonally as shown in the diagram. In this case, the main scanning direction from the reference point sp on the document glass μ is
The coordinates P+(
X+, Y+), P2(X2, Y2), P3(
X3. Y3) and p4 (X41 Y4) are detected by scanning 11f1 with the optical system, thereby determining the size and position of the document. Note that the document cover surface 3a is mirror-finished as described above so that image data outside the area where the document 20 is placed is always black data. In pre-scanning, main scanning and sub-scanning are performed to cover the entire glass surface, followed by scanning for image reading and image recording.

FIG. 73 is a circuit diagram of a document detection device for detecting the coordinates. Based on this, the circuit processing will be sequentially explained below. Image data (VIDEO) converted into a white image or a black image by pre-scanning is input to the shift register 30 in units of g bits. When the g-pit input is completed, the gate circuit 3/ checks whether all of the g-pit data is a white image, and if Yes, the signal lines 3 and 2 are
Output / to.

F/F when the first g-bit white appears after scanning the original
33 is set. Kono F/F 33 +t, VS
It is reset in advance by YNC (image leading edge signal) and is left set until the next VSYNC signal.

When the F/F 3.3 is set, the value of the main scanning counter 3S at that time is loaded into the launch 34L. This is point P
The X coordinate value of 1 becomes X. At the same time, the value of the sub-scanning counter 37 at that time is loaded into the latch 3B. This is point P
The Y coordinate value of 1 is Y. Therefore, the coordinates of point P1 (Xl,
Y,) is found.

Also, each time / is output to the signal lines 3 and 2, the value of the main scanning counter 3S is loaded into the latch 3g. This value is immediately changed to (
until the next g pit data enters the shift register 30)
It is stored in latch 3W. When the value of the main scanning counter 3 at the time when the white of the first g pit appears is loaded into the latch 39, the latch.

'IOc (this is set to 110n at the time of VSYNC) is compared in size with the data of comparator ll/.

If the data in latch 39 is larger, the controller outputs a signal and the data in latch f3g (this is the data in latch 3).
9) is loaded into latch llO.

Further, the value of this time scanning counter 37 is loaded into the latch l12. This operation is processed until the next g pit enters the shift register 30. If the data comparison between latch 3'7 and latch lI0 is performed for the entire image area in this way, the maximum value in the X direction of the document area remains in latch 0, and the coordinate in the Y direction at this time remains in latch '12. It turns out. Therefore, the coordinates (X2.Y2) of point P2 are found.

F/'F4t3 is an F/F that is set when g-bit white appears for the first time in each main scanning line, and the horizontal dot signal H8 is set.
It is reset at YNC, set at the first g pit white, and held until the next H8YNC. At the time when this F/F group 3 is set, the value of the main scanning counter 3S is latched tllI
and loads it into latch ILS until the next H8YNC. Then, the latch llB and the comparator q7 compare the size. The maximum value in the X direction is preset in the latch 11B at the time VSYNC occurs. If latch 4
．． If the data in latch 45 is greater than the data in latch 45, comparator 117 outputs a signal and the data in latch 11 (which is equal to the data in latch l13) is transferred to latch q.
This operation is performed by H8YNC and the next H8
This will be done with YNC. If the above comparison operation is performed for the entire image area, the minimum value of the document coordinates in the X direction will remain in the last area. This is the X coordinate value of point P3
It is. At the same time, the value of the sub-scanning counter 37 is loaded into the latch ttg by the output signal from the comparator l17. This becomes the Y coordinate value Y3 of point P3. Therefore, point P3 (X3.Y3) is found.

Each time a white g pit appears in the entire image area, the values of the main scanning counter 3S and the value of the sub-scanning counter 37 at that time are loaded into the latch tags 9 and SO.

Therefore, when the document pre-scanning is completed γ, the count value at the time when the g-pit white appears last remains in the latches Ilq and SO. As a result, point P4 (X4°Y4) is found.

More than three latches C311-, 3 ot, llo, 11 Ω
.

Guotsu, l1g, '19,! ;0) is connected to a pass line (BUS) of a CPU (not shown), and the CPU reads this data at the end of the previous scan. Then, among these data, the point (X,,Y,)
, (X2 + Y+), (Xl, Y4), and (X2, Y4) is determined as a document area. Based on this, processing such as determining the stroke for reading the number of legs and selecting a paper feed cassette of a desired size is performed when scanning the document for recording the number of strokes.

Therefore, even when detecting the document position as described above, the present invention can accurately detect the position of the document regardless of the type or material of the document by the action of the document cover member, which is the most characteristic feature of the present invention. This makes it possible to easily set the white level or black level, and eliminates the risk of malfunction, which provides a very high fpi effect.

[Brief explanation of the drawing]

FIGS. 1(a) and (b) are explanatory diagrams showing the drawbacks of the conventional document cover part H, and FIG. 2 is a schematic diagram showing an example of an image processing apparatus to which the document cover part side, which is a feature of the present invention, is applied. , FIG. 3 is a cross-sectional perspective view showing a part of an embodiment of the document cover member which is a feature of the present invention, FIG. 9 is an explanatory diagram showing the positional relationship between the document cover surface and the document platen glass, and FIG. 4 is an explanatory diagram showing the principle of overturning a document and reflecting light on a member, which is a feature of the present invention; FIG. 7 is a schematic diagram showing a state in which a document is placed; FIG. S (a)
and (b) are waveform diagrams showing signals detected by the document detection device, and FIG. 9 to FIG. /2
The figure is a schematic diagram showing a state in which an original is placed on the original table glass, and FIG. 73 is a circuit diagram of an original detecting device for detecting the original position. ／・・・・・・Image, also “JJy, part, Yu...”
・Manuscript table glass. 3...Document cover side, 3a...Document cover side. 3b...Mirror sheet, 3C...Mirror surface. 3d...board, 3e...foot. 3f...Cover, 3g...Elastic member. 3h: Colorless and transparent elastic member. G... Light source, 5. Buddha 7...mirror. g...lens, q...solid-state image sensor. 10... Image recording section, //... Semiconductor laser. /2... Rotating polyhedron, /3... Mirror. /G... Photosensitive drum. Patent applicant: Canon Co., Ltd. Figure 1 (0) 383- Figure 4 Figure 6 Main running wear and tear Figure 7 (a) (b) Figure 8 Figure 12:

Claims (3)

[Claims] (1) An image including a cover member having a mirror surface on a surface that covers a document to be read, a light source for illuminating the image surface of the document, and an image sensor that detects reflected light from the light source and converts it into an electrical signal. An image processing device characterized in that the mirror surface of the cover member is a surface that does not undergo local deformation due to external force. (2) The image according to claim 1, wherein the cover member forms the mirror surface by vapor-depositing or laminating aluminum on a sheet-like transparent elastic member, and reinforcing this with a hard member. Processing equipment. (3) The image processing apparatus according to claim 7 or 5, wherein the surface of the top member that covers the document is smaller than the document table glass surface.