JPH06326839A - Picture reader - Google Patents

Abstract

(57) [Summary] [Purpose] Reflective and transmissive originals with a simple structure
Read without degrading image quality. [Structure] A transparent original D ₂ is placed on an original table 5 with the image surface Da facing upward. Reflective surface 15a of sheet material 15
Is brought into close contact with the image surface Da by the elastic member 19. The light emitted from the light source 7 below the document placing table 5 passes through the document placing table 5 and the base material Db of the document D and is reflected by the image surface Da and the reflecting surface 15a on the same plane as the base material D.
b, re-transmitted through the document placing table 5, and reflected mirrors 9a to 9d,
It is read by the line sensor 11 via the lens 10. Since this is a mirror image, it is converted into a normal image by the conversion means. The reflective original is placed with the image surface Da facing downward, and is similarly read by the line sensor 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus which is suitable for being mounted on an image forming apparatus such as a copying machine or a laser beam printer, and more particularly to a reflection type original and a transmission type original having a simple structure. The present invention relates to an image reading device capable of reading images from both sides.

[0002]

2. Description of the Related Art Conventionally, different image reading apparatuses mounted on an image forming apparatus such as a laser beam printer are used depending on whether a document to be read is a reflection type or a transmission type. Here, the reflective original is an original such as a printed matter or a copy in which an image is formed on the surface of a non-translucent base material such as paper, while the transparent original is
For example, an original document for overhead projector projection (hereinafter referred to as “OHP sheet”) having an image formed on the surface of a transparent substrate such as a transparent film. In general, an image reading apparatus for a reflective original cannot read an image of a transparent original, and conversely, an image reading apparatus for a transparent original cannot read an image of a reflective original. Therefore, this is difficult even though it is required to read various originals including printed matters and OHP sheets for general purpose with one image reading device.

In recent years, however, a configuration has been put into practical use in which both a reflection type original and a transmission type original can be read by selectively changing a part of the configuration of the image reading apparatus. When this image reading apparatus is used for a reflection type document, the reflection type document is placed on a translucent document placing table with the image surface facing downward, and an open / close cover is placed on the reflection type document. The image surface is illuminated by a light source arranged below the table, and reading is performed by the reflected light from the image surface at this time. On the other hand, when reading a transmissive original, the open / close cover should be removed and the light source for the transparent original should be placed instead, and the light transmissive original placed on the original table with the image side facing down should be placed on the rear side. Irradiation is performed from above (from above), and reading is performed by the transmitted light at this time. That is,
Both the originals can be read by appropriately replacing the open / close cover for covering the reflective originals and the irradiation light source for the transparent originals according to the reflective or transmissive originals.

As a further development of this system, there is known one in which the above-mentioned opening / closing cover and the irradiation light source for the transparent original are integrated. As shown in FIG. 6, the image reading apparatus 1 includes an apparatus body 2 in which a transparent glass table (original table) 5 is fitted on the upper surface, and an opening / closing cover 3 which covers the glass table 5 so as to be opened and closed from above. I have it. Below the glass table 5, irradiation light sources 7 and 7 for reflecting originals and reflecting mirrors 9a, 9b and 9C, which are movably arranged in the direction of arrow K1, are provided.
A lens 10 and a line sensor 11 such as a CCD are arranged. On the other hand, below the opening / closing cover 3, a transparent holding glass 12 is arranged, and the document D, which is an image reading target, is sandwiched between the above-mentioned glass table 5. In addition, inside the opening / closing cover 3, an irradiation light source 13 for the transparent original that irradiates the transparent original from the back side (upper side) and the irradiation light source 13 are synchronized with the reflection mirrors 9a, 9b, 9c, etc. A drive mechanism (not shown) for moving the drive is arranged. With such a configuration, when the document D to be read is a reflection type document, it is placed on the glass table 5 with the image surface facing downward,
While moving the lower irradiation light sources 7, 7 in the direction of the arrow K1, the image surface is irradiated thereby (the upper irradiation light source 13 is turned off at this time), and the reflection mirrors 9a, 9b are reflected by the reflected light from the image surface. 9c, the image is read by the line sensor 11 via the lens 10. On the other hand, even when the original document D is a transmissive original document, the original document D is sandwiched between the glass table 5 and the pressing glass 12 with the image surface facing downward, and the original document D is used as the irradiation light source 13 for the upper transparent original document. While irradiating, the irradiation light source 13 is moved in the direction of arrow K1 and the transmitted light that passes through the document D from the upper side to the lower side is reflected by the lower reflection mirrors 9a, 9b, 9c (broken lines in FIG. 6).
It is read by the line sensor 11 via the light source. In this way, a mechanism capable of reading both the reflective original and the transmissive original is provided, and both originals can be read by switching the mode, for example.

[0005]

However, the provision of the mechanism capable of reading the reflection type original and the transmission type original as in the above-mentioned conventional technique requires that a dedicated reading device is prepared for each of them. Compared to the one that replaces the opening / closing cover and the irradiation light source for transparent originals, although the overall configuration is simplified and the image forming time is shortened, various problems have been pointed out as follows. There is. In the image reading apparatus described above, the reflection type original is placed on the glass table 5 with the image surface facing downward, and the holding glass 12 for the transparent original is arranged on the back side thereof. That is, the glass table 5
The transmissive original is sandwiched between the pressing glass 12 and the pressing glass 12. In this state, since the transmissive original is brought into close contact with the pressing glass 12, a density change or a streak-like dark portion is likely to occur partially. In order to solve this problem, it is necessary to use, as the holding glass 12, one provided with an anti-reflection means such as an uneven surface, and irradiate the transmissive original so that the transmitted light becomes a diffused light state due to the unevenness. For example, the structure of the presser glass 12 is complicated and expensive. Further, although one reading device 1 can read both reflection type and light transmission type documents, the irradiation light sources 13, 7 and 7 are provided on the glass table 5.
However, two sets of mechanisms for driving the irradiation light source are required, and the structure of the entire apparatus is still complicated.

Therefore, an object of the present invention is to provide an image reading apparatus capable of reading both a reflection type original and a transmission type original with a simple structure.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and an original set on the placing surface of the upper surface of a translucent original placing table is placed below the original placing table. In an image reading device which irradiates with an arranged light source and reads the original through reflected light from the original, an image surface is provided on one surface of a transparent film substrate, and the image surface is directed upward. With respect to the transmissive document set on the mounting surface of the document mounting table in this state, a reflective surface that comes into contact with the image surface of the transmissive document from above and a pressing member that brings the reflective surface into close contact with the image surface are provided. The original document holding table, which is irradiated with the light source, is transmitted through the original document placing table and the base material of the transparent original document, is reflected by the image surface of the transparent original document and the reflecting surface of the original document original table, and Through the light that re-transmits the material and the document table Reading means for reading the image information on the image surface, memory means for storing the image information read by the reading means, and identification means for identifying whether the original document on the original table is a transparent original document or a reflective original document. When the output from the identifying means is a transmissive original, there is provided conversion means for converting a mirror image into a normal image based on the image information of the memory means.

The identifying means places the image surface upward when the original placed on the original table is a transmissive original, and directs the image surface downward when the original is a reflective original. Prescan means for determining whether or not the vertical orientation of the image surface of the document to be read on the document mounting table meets the above-described placement standard with respect to the placement standard that the document is placed. May be.

[0009]

According to the above-described structure, the reflection type original is placed on the placing surface of the original placing table with the image surface facing downward, and when the light source below the original placing table irradiates the original, the irradiation light causes the original placing table to move. The light is transmitted from below, is reflected by the image surface that coincides with the document mounting surface, becomes reflected light, and this time is transmitted through the document mounting table from above to below, and is read by the reading means (for example, a line sensor). On the other hand, the transparent original is placed on the original placing table with the image surface facing upward. When reading images,
A reflecting surface is brought into close contact with the original surface via a pressing member. When a translucent original is illuminated by the same light source as that of a reflective original, this illumination light first passes through the original placing table from below, then passes through the transparent base material of the light-transmissive original, and is almost flush with the same plane. Is reflected by the image surface and the reflection surface, and the reflected light is subsequently re-transmitted from the upper side to the lower side of the base material and the document placing table. The reading means reads the image information on the image surface of the transmissive original by the retransmitted reflected light.

By the way, in the above-mentioned transmission type original, a normal image is usually formed by transmitting the light emitted from the back side, and therefore, the above-mentioned image plane directed upward is viewed. A mirror image is formed depending on the reflected light. This mirror image can be converted into a normal image by the conversion means.

It is to be noted that whether the original placed on the original placing table is a reflection type or a transmission type is confirmed by the identifying means. And
In the case of a transmissive original, activate the above conversion means,
On the other hand, in the case of a reflection type original, the converting means is not operated.

By doing so, it is possible to read both the reflection type original and the transmission type original with a simple structure.

[0013]

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

In the present invention, when the original D placed on the placing surface 5a of the original placing table 5 shown in FIG. 1 is a reflection type original, the image surface is directed downward, If the original D is a light-transmissive original, the image surface is placed with the image surface facing upward. Here, before the description of the specific contents of the present invention, it is preferable that the transmissive original is placed on the original placing table in the same manner as the reflective original, that is, the image surface thereof faces downward. The reason why the image cannot be read will be described.

That is, as shown in FIG. 7, as in the case of reading a reflective original with the original D placed on the original table 5 by a reflective original reader using a flat bed type image scanner. The image surface Da to be read is placed in the downward direction in contact with the placing surface 5a, is placed on the placing surface 5a, and the light source 7 arranged below the document placing table 5 moves the image surface Da from below to the image surface Da. Irradiation is performed at an incident angle of 30 to 40 degrees with respect to the perpendicular H, and the image surface Da on the transparent film-shaped substrate Db is read by reflected light,
First, it will be described why it is impossible to form an image on the line sensor pixel through the optical lens to read it and perform photoelectric conversion.

As the transmissive original D ₂ described above, for example, an OHP sheet is well known, and an image is generally formed by silver salt photographic emulsion, ink jet jet recording, sublimable thermal transfer ink recording and the like.

Most of these transparent originals D ₂ are
An image is formed as an image film layer on one surface of the transparent film-shaped substrate Db (the surface on which the image is formed is hereinafter referred to as "image surface Da"). This image often has an image surface Da on the surface on the viewing side when viewed as a normal image. The image plane Da, as in the case of reflection originals D _1, as shown in FIG. 7, being directed downward, i.e. in contact with the mounting surface 5a of the document table 5 the upper surface, the lower light source 7 side The transparent original D ₂ is placed with the sheet material 15 facing upward, and is pressed from above by the sheet material 15 that prevents the rearward (upward) floating. A contact surface 1 that is in contact with the lower surface of the sheet material 15, that is, the upper surface of the transparent original D _2.
5a, the open / close cover is closed by pressing the upper surface of the transparent original D ₂ from above, and then the image surface Da is read. As shown in FIG. 7, in this reading, the transparent original document D is passed through the transparent original document table 5 from below.
_The image surface Da on the lower surface side of ₂ is illuminated by the light source 7,
The reflected light La from the image surface Da is imaged by the lens on the line sensor pixel as in the case of the reflection type document reading,
read. However, unlike the reflection type document D ₁ , the transmission type document D ₂ has a transparent base material Db, so that an image on the image surface Da having an intermediate density has a surface reflection light La and a transmission light according to the density. The light that has been divided into the components and has passed through the image further passes through the base material Db and reaches the contact surface 15a on the lower surface of the sheet material 15 for preventing the image floating described above. In general, the sheet material 15 to be pressure-contacted is often a white resin material, and a passing image projects a shadow on the contact surface 15a of the sheet material 15 and is further reflected downward to be reflected light Lb again to become a transmissive document. D
Pass through image ₂ from top to bottom this time. When this state is viewed from below, the image is shifted due to the deviation of the reflected lights La and Lb, and the line sensor 11
As shown in FIG. 8, information having two peaks appears on the pixel row of, and therefore, it appears as a double image.

That is, it appears as a ghost-like pattern that often appears on the television image surface, and this image state is faithfully imaged and read on the pixels of the line sensor.

Further, in the transmissive original D ₂ having a color image, it is 30 to 30 with respect to the perpendicular to the color image surface Da.
When irradiated with irradiation light having an incident angle of 40 degrees, a color image surface-reflected by the color image surface Da facing downward,
After that, the color image in which the reflected light is transmitted is displaced from the contact surface 15a. That is, the transmitted light that has once passed through the color image re-projects a shadow on the contact surface 15a of the sheet material 15 on the back surface side, so that the color image is projected according to the incident angle and is reflected again at the inclination angle. Since the reflected light passes through the adjacent point that is slightly deviated from the point described above on the surface Da, and as a result, two color images in which the two reflected lights are slightly deviated are formed, the original color image before reading is In some cases, the color tone becomes remarkably different, which is read by the pixel of the line sensor, and it is impossible to read the color information of the original color image faithfully.

As described above, according to the above-described method, since a fundamental image defect occurs in the reading device, as described in the conventional technique with reference to FIG. 6, the image surface Da of the transmissive original D ₂ is described. In reading, the image plane D having an image
The light source 1 dedicated to the transmissive original D ₂ is provided on the back side opposite to a.
3 is arranged so that a high quality image is read.

According to the present invention, when the transmissive original D ₂ is read, the transmissive original D ₂ is illuminated by the common light source 7 from the same surface side as the reflective original D ₁ is read, as shown in FIG. It is possible to prevent deterioration of image quality such as color mixture of ghost patterns without adding a dedicated light source 13 and its driving mechanism from the rear side. That is, according to the present invention, it is possible to read the reflective original document D ₁ and the transmissive original document D ₂ with a simple structure without deteriorating the image quality.

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

1 and 2 are a perspective view and a vertical sectional view showing the outline of an image reading apparatus according to the present invention. 3 and 4, the reflection-type original document D ₁ and the transmission-type original document D ₂ placed on the original image placing table 5 of FIG. 2 are placed on the original placing table 5.
2 shows the reading scanning direction and the restoring direction when viewed from the side of the light source 7 arranged below.

As shown in FIG. 1, the image reading device 1 includes
The apparatus main body 2 and an opening / closing cover (document holding table) 3 that covers the upper surface of the apparatus main body 2 are provided. An operation unit 16 for switching the reading mode of the original depending on whether the original is a reflective original D ₁ or a transparent original D ₂ is arranged in the apparatus main body 2, and the opening / closing cover 3 is provided at the front end side of the opening / closing cover 3. A lock mechanism 17 for fixing the main body 2 is attached.

As shown in FIG. 2, on the upper surface of the main body 2 of the apparatus, a document placing table 5 made of a transparent glass plate is arranged. A light source 7 is arranged below the document table 5,
The open / close cover 3 above the document table 5, that is, in the closed state
An original pressing sheet material (sheet material) 15 having a white reflecting surface 15a facing the placing surface 5a on the upper surface of the original placing table 5 is disposed on the lower surface of the sheet. An elastic member (pressing member) 19 is filled above the sheet material 15 (on the back side), and the elastic member 19 places the original document D on the original document table 5 and from above the original document D. When the opening / closing cover 3 is closed, the documents D are pressed against the placement surface 5a of the document placement table 5 on average. Next, the hook 1 of the rotating lock mechanism 17
It is locked at 7a and preparations for reading are made. Placement surface 5a
As the original D placed on the sheet, there are a case of a reflective original D _{1 and} a case of a transparent original D ₂ , but in this embodiment,
The latter transmissive document D ₂ will be described in detail.

The transmissive original D ₂ is composed of a transparent film substrate Db and an image film surface (image surface) Da formed on one surface of the substrate Db. When the transparent original D ₂ is placed on the original placing table 5, the placing surface 5a is used.
The base material Db side is placed on and the image surface Da is placed so as to face upward. Next, when the open / close cover 3 that is open is closed, the sheet material 15 on the lower surface of the open / close cover 3 becomes transparent.
₍₂₎ The image surface Da on the upper surface is brought into contact with the image surface Da. Then, the elastic member 19 on the back surface of the sheet material 15 further presses the image surface Da so that the entire surface is uniformly and evenly contacted.
The elastic member 19 may be made of a foam rubber material or an air bag (neither is shown).

With such a configuration, the document D during the reading operation has a pressure spring 20 on the base end side (right side in FIG. 2) of the opening / closing cover 3 and a lock mechanism 17 on the front end side (left side in FIG. 2).
Maintain a stable state by The transparent original D
_For maintenance of ₂ , you can also use a strong magnet.

The reading optical system, that is, the light source 7, the reflection mirrors 9a, 9b, 9c and 9d, the lens 10, the line sensor 11 and the like are arranged below the original table 5 on which the transparent original D ₂ is placed. This is basically the same as that used in a reading device for reading the image surface of the reflective original D ₁ , and the light source 7 is a tubular light source such as a fluorescent lamp rather than an irradiation light source having a filament. A reflector light source that emits uniform irradiation light over the entire area is preferable, and the irradiation light that is turned on and irradiated is directed in the thickness direction of the original mounting table 5 and the base material Db of the transmissive original D ₂ from the bottom to the top. To the image surface Da.
Reflective surface 15a of the white sheet material 15 in contact with the image surface Da
Is secondarily reflected at this time, and this time becomes reflected light which goes downward, and re-transmits through the image surface Da, the base material Db, and the document mounting table 5,
An image is formed on a pixel of the line sensor 11 via the reflection mirrors 9a, 9b, 9c, 9d, a lens and the like. That is,
The transmitted irradiation light that travels back and forth on the image surface Da of the transmissive original D ₂ is color-separated, and color image information is read on the pixel rows of the line sensors 11 provided side by side and photoelectrically converted to obtain color image data. Obtainable.

As described above, the color image surface D of the original document D
a and the reflecting surface 15a of the sheet material 15 that presses the image surface from above are surely brought into close contact with each other, so that the light source 7
Light reflected by the image surface Da and emitted by
Since the reflected light that has passed through the image surface Da, is reflected by the reflecting surface 15a, and has re-transmitted through the image surface 15a can be accurately matched, high-quality color read data with no ghost or color mixture can be obtained. be able to.

The image surface Da of the original document D and the sheet material 15 described above.
The reflection surface 15a of the reflection type image D ₁ and the reflection surface 15a of FIG.
As in the case of reading the original document, even if the irradiation angle (incident angle) with respect to the image surface Da originally exists, the deterioration of the image quality should hardly occur as described above.

From this fact, the contact state between the two different image surfaces Da and the reflecting surface 15a becomes unstable, and for example, a thin air layer or the like is generated between the two, thereby preventing a slight floating. Therefore, it is necessary to apply uniform and uniform pressure from the back side (above) of the reflecting surface 15a.

A transparent original D ₂ such as a so-called positive film made of a silver salt film or an overhead projector (OHP) film used to obtain a magnified projection image is visually checked so that the image becomes a normal image. When this is done, the image surface Da generally comes to the surface on the visual side, while the image reading apparatus 1 transfers the reflection type document D ₁ onto the mounting surface 5a of the document mounting table 5 of the reading apparatus. Since the read data taken out after photoelectric conversion is set to be a normal image when the image is read with the Da side placed, when the transparent original D ₂ is placed on the original placing table 5, the image is read. When the document is placed with the surface Da facing upward and is read, the read data is a mirror image, unlike the case of the reflection type document D ₁ described above. However, after temporarily storing the read data in the memory device, the data on the line in the main scanning direction is taken out from the opposite side to the reading direction, so that a so-called reverse image in the left-right direction can be formed. That is, it becomes possible to form a right image. Such a conversion could easily be done only by digitizing the read data. An example of the above-described conversion of a mirror image into a normal image will be described in detail with reference to FIGS. 3 and 4. 3 and 4, the reflection-type original document D ₁ and the transmission-type original document D ₂ are placed on a transparent original document table 5 (not shown), and these are viewed from below (from the light source side). It is a figure which shows a scanning direction and a restoration direction.

When the image surface Da of the reflective original D ₁ is read (see FIG. 3), the image surface Da is placed on the original table 5 described above.
One-dimensional line sensor 1 such as CCD mounted with its side facing
At 1, the original image is read in the X direction in the main scanning direction, and then in the Y direction in the direction orthogonal to the line sensor 11 (not shown in the figure). In this method, the image surface Da and the line sensor 11 are moved relative to each other, and the image surface Da is disassembled and read based on the set predetermined line-to-line density. The above main scanning reading is repeated along with the sub scanning transfer, and the read information by the pixels of the line sensor 11 is photoelectrically converted to sequentially obtain digital data. As shown in Figure 3,
The X direction is the main scanning and the Y direction is the sub scanning, and the electronic scanning reading is performed by the pixels on the line sensor 11 from the base point 0 in the direction indicated by a in the direction indicated by a, and the scanning is performed by disassembling in the Y direction. If the image data is sent out and displayed on the recording head unit for re-recording the read data, the CRT display tube, or the liquid crystal surface according to the same means as at the time of reading, the image information before reading becomes It is reproduced as the same positive image as this. When reading the transmissive original D ₂ (see FIG. 3), when the transparent substrate Db side with the image surface Da facing up is placed on the original placing table 5 for reading, the image viewed from the reading side is the film base. It will be seen through, and as shown in the figure, it is seen as a mirror image in which the left and right sides are opposite images. When the reading device scans the mirror image in the X and Y directions, the images are sequentially read as indicated by the solid arrow. If this reading is photoelectrically converted and the data is sent out in the same procedure, the left and right are faithfully reproduced as mirror images of the left and right, so the data is stored in the memory device 21, and only the main scanning direction is read from the right. If it is taken out to the left from the opposite side as shown by the broken line and is transmitted to the recording or display unit in the same manner as described above and reproduced by the image data, a normal image as shown in the figure is reproduced.

As described above, the image information on the image surface Da is point-decomposed and read, and the rearrangement is performed, so that it is possible to read the transmissive original D ₂ while faithfully maintaining the high image quality. It was When reading the transmissive original D ₂ , an optical system with an additional reflection mirror is required to read an image as a normal image with only the optical system, which complicates the apparatus configuration. As described above, the conversion from the mirror image to the normal image can be easily performed by the reading device that digitizes the information after photoelectric conversion.

The original to be read is a transparent original D ₂
In this case, at the time of reading, for example, the reading may be started after inputting that the original is a transmissive type with an operation key or the like. The prescan means 23 can automatically determine whether the document is a reflective document D ₁ or a transmissive document D ₂ . That is, as shown in the block diagram of FIG. 5, for example, after placing the transparent original D ₂ on the original table 5, partial reading of information imaged on the pixels of the line sensor 11 by prescan is performed, When it is possible to identify the transparent original D ₂ and that the ghost state does not occur, it means that it is confirmed that the image surface Da is placed with the correct upward orientation. It is possible to improve the efficiency of the reading work by starting the normal reading scan, causing the X and Y scanning readings to be performed over the entire image surface Da, and then converting the reading data into a normal image.
FIG. 5 is a block diagram of this.

When a ghost is identified by the prescan data, the operation unit 16 or CR
It is also possible to notify the T liquid crystal display unit or the like of an erroneous setting of the front and back directions and prompt the correct remounting of the transmissive original D ₂ .

The identification and control of these can be easily performed by the line sensor 11 provided in the apparatus main body 2 by a known technique conventionally used. For example, as an example, recognition and identification can be performed by the following method.

[0038] As previously mentioned, toward the image plane Da on the mounting surface 5a side of the document table 5 is placed, when reading the transmission original D ₂ is at an incident angle of 30 to 40 degrees When the image surface Da is illuminated, a ghost image having two peaks as shown in FIG. 8 is generated. Therefore, in order to determine this waveform pattern, a similar waveform for certification is stored in the memory device 21 of the apparatus main body 2, and when it is possible to compare and recognize that the pre-scan data is similar to this waveform, It can be recognized that the transmissive original D ₂ is placed upside down.

Based on this recognition, the operator is informed by the display means or the like that the placement is wrong, and the operator is prompted to place the transparent original D ₂ again. As described in the foregoing examples, and the image plane Da up, contact a reflecting surface 15a of the image surface Da and the sheet material 15, and maintained by pressurized transmissive original D ₂ of the substrate Db The transmissive original D ₂ is read by irradiating the image surface Da from the side to perform reading, and when the read data is correctly read, the conversion means 22 for controlling the conversion of the data from the mirror image to the normal image is also used. It is possible to read without deteriorating the color image quality. The conventional transmissive reading light source from the back side (upper side) of the transmissive original D ₂ changes the device each time depending on whether the original is reflective or transmissive, and turns on and drives the light source for irradiation. Compared with a known reading device that performs scanning switching reading operation, the optical system including the light source 7 and the driving mechanism can be used to adapt to any document, and the read image quality is deteriorated. It has become possible to read without causing

In the above-described embodiment, the sheet material 15 having the reflecting surface 15a which is brought into close contact with the image surface Da of the transmissive original D ₂ is preferably, for example, a resin sheet material, and the surface of the sheet can be used repeatedly. , A material that does not easily adhere such as dirt, or a surface with good smoothness that can be easily removed with an aqueous detergent even if dirt is found. Further, the surface reflectance of the paper most frequently used as the reflection type document D ₁ is selected. If a value close to the average reflectance is selected and set in advance, lighting and adjustment of increase / decrease in the exposure amount of the light source 7 become unnecessary. When scanning the transmissive original D ₂ , the reflective original D
Compared to when reading ₁ , 2 reciprocating in the substrate Db
When the light is transmitted, the light amount is lost by about 20% and the output level of the line sensor 11 is lowered. However, the calculation processing is performed on the basis of the case of the reflection type document D ₁ to perform digital processing. Gradation can be corrected by data swing correction. This kind of correction method is used when correcting a standard reading value that occurs when switching reading is performed in a device having a reflective original reading and an ADF (automatic original feeder) original reading. It can be easily corrected by various known techniques.

[0041]

As described above, according to the present invention,
For a transmissive original placed on the original placing table with the image surface facing upward, a pressing member for bringing a reflecting surface into close contact with the image surface, and a conversion means for converting a mirror image into a normal image are provided. Since the image surface of the transmissive original can be read as a normal image by using the optical system used when reading the original, the overall structure can be simplified without degrading the image quality.

[Brief description of drawings]

FIG. 1 is a perspective view showing an entire image reading apparatus according to the present invention.

FIG. 2 is a vertical sectional view showing an outline of the image reading apparatus.

FIG. 3 is an operation explanatory diagram showing reading, reproduction, and restoration of a reflective original.

FIG. 4 is an operation explanatory view showing reading, reproduction and restoration of a transparent original.

FIG. 5 is a block diagram showing reading of a reflective original and a transparent original.

FIG. 6 is a longitudinal sectional view showing the outline of a conventional image taking device.

FIG. 7 is an operation explanatory view showing reading of a conventional transparent original.

FIG. 8 is a diagram showing a double image generated when an image is read on a transmissive original with the image surface thereof facing downward. [Brief Description of Drawings] 1 image reading device 2 device main body 3 document holding table (opening / closing cover) 5 document placing table 5a placing surface 7 light source 11 reading means (line sensor) 15a reflecting surface 19 pressing member (elastic member) 21 Memory means (memory device) 22 Conversion means 23 Identification means (prescan means) D Original D ₁ Reflective original D ₂ Transparent original Da Image surface Db Substrate

Claims (2)

[Claims] 1. A document set on a mounting surface of an upper surface of a translucent document mounting table is illuminated by a light source disposed below the document mounting table, and the document is read through reflected light from the document. In an image reading apparatus, a transparent original having an image surface on one surface of a transparent film-like substrate, and a transparent original set on the original surface of the original table with the image surface facing upward An original holding plate having a reflecting surface that comes into contact with the image surface of the transmissive original from above and a pressing member that brings the reflecting surface into close contact with the image surface; and the original placing table and the transmissive type that are illuminated by the light source. The image information of the image surface is transmitted through the base material of the original document, reflected by the image surface of the transparent original document and the reflection surface of the original document holder, and retransmitted through the base material and the original document table. Reading means for reading, and the reading means Memory means for storing the read image information, identification means for identifying whether the original document on the original document table is a transmissive original document or a reflective original document, and when the output from the identifying means is a transmissive original document, the memory means An image reading device comprising: a conversion unit that converts a mirror image into a normal image based on image information of the unit. 2. The identifying means places the image surface upward when the original placed on the original placing table is a transmissive original, and directs the image surface downward when the original is a reflective original. A pre-scanning unit that determines whether or not the vertical orientation of the image surface of the document to be read on the document placement table meets the above-described placement standard with respect to the placement standard that the document is placed on the document placement table. An image reading apparatus according to claim 1, wherein: