JP3571276B2 - Image reading device and image forming device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image reading apparatus for scanning a document image, optically reading the image, and outputting electronic data, and in particular, a thick document placed on a platen glass (hereinafter, referred to as a “platen”). Image reading device for reading images on both sides of a document sheet fed one by one from a document receiving tray by an automatic document feeder usually called an ADF while reading images such as About.
[0002]
[Prior art]
2. Description of the Related Art An image forming apparatus such as a copying machine and a facsimile machine includes an image reading device that optically reads a document image and converts the image into electronic data.
[0003]
Copiers and the like equipped with such an image reading apparatus often place a thick original such as a book on a third platen, and a first image sensor provided below the platen is fixed. A first reading method for reading an image on a document surface while moving at a constant speed in a direction, and a first image sensor fixedly disposed below a first platen adjacent to the third platen, and automatic document feeding is performed. The apparatus also has a second reading method for reading an image on a front surface (downward facing surface) of a document sheet fed one by one from a document receiving tray by the apparatus and conveyed at a constant speed.
[0004]
Further, in the second reading method, the image on the back surface (upward facing surface) of the document sheet fed one by one by the automatic document feeder is transported so as to be read simultaneously with the image reading on the sheet surface. A second image sensor and a second platen are provided on the opposite side of the first platen with respect to the third platen with respect to the original sheet to be transported, and complicated conveyance and travel control such as switchback conveyance of the original sheet is provided. There has been proposed an image reading apparatus configured to read images on both sides of a document sheet in one document conveyance pass without performing the above operation.
[0005]
Examples of such an image reading apparatus having two image sensors for reading images on both sides of a document sheet are disclosed in JP-A-7-327111, JP-A-11-187268, and JP-A-11-32164. In each of these publications, it is disclosed.
[0006]
Japanese Unexamined Patent Publication No. Hei 7-327111 discloses a method in which separate reduction optical system image sensors are provided on both upper and lower surfaces of a document sheet conveyance path, and two platens of a first platen and a third platen are connected to one transparent glass plate. A two-sided image reading device that has been attacked to provide a reflector with a difference in the reflectance of the reflecting mirror that constitutes the image sensor and absorb the difference in the amount of light when reading the transparent document and the opaque document Has been disclosed.
[0007]
Japanese Patent Application Laid-Open No. 11-187268 discloses a method for reading a double-sided image of an original sheet fed automatically without providing a means for the first reading method (image reading of a thick original or the like). An image sensor of a reduction optical system below the document conveyance path, and an image sensor of a unity close contact optical system above the conveyance path, and two separate platens corresponding to the two image sensors; An image forming apparatus in which a transport roller is disposed between two platens is disclosed.
[0008]
Further, Japanese Patent Application Laid-Open No. H11-32164 discloses that an image sensor of the same size contact type and a reduction optical system image sensor are provided on the upper surface side and the lower surface side of the original sheet conveying path, respectively, and the order of the traveling path of the original conveyed by rotation is set. A platen for reading the lower surface of the automatic transport document sheet (corresponding to the first platen), a platen for reading the upper surface of the automatic transport document sheet (corresponding to the second platen), and finally a platen for placing a thick document. (Corresponding to the third platen) is disclosed.
[0009]
[Problems to be solved by the invention]
However, in order for the images on the front and back sides of the document sheet conveyed by the automatic document feeder to be precisely read by two separate image sensors without being in a so-called pinching state, at least during the reading time, It is necessary that the conveyed document is conveyed while maintaining the depth of focus with respect to the set reference position (running position).
[0010]
In particular, when either the first or second image sensor uses a close-contact type image sensor of a 1: 1 optical system image sensor, the separation margin between the document surface and the reading surface of the reading device is determined by using a CCD. It is smaller than that of the conventional reduced optical system image sensor, and it is necessary to sufficiently ensure the proximity running property between the document sheet and the platen surface.
[0011]
Further, in order to make the image reading apparatus lighter and smaller in size, a reading position for reading one surface (front surface) of the document sheet and the other surface (back surface) of the document sheet are read. It is necessary to make the reading positions as close as possible without separating them. This is because, if both reading positions are arranged adjacent to the ADF conveyance direction, the image reading apparatus must be lengthened in the document conveyance direction in accordance with the two reading positions, and the entire apparatus becomes large.
[0012]
From this point of view, all of the above-described image reading apparatuses according to the related arts achieve stable running of the document sheet, are reduced in size, and reduce the number of components to reduce the failure occurrence rate. Was insufficient.
[0013]
According to the present invention, the outer shape of an image reading apparatus capable of reading both sides of a document sheet is smaller and lighter in the left-right direction and the up-down direction, and the document sheets stacked on the document receiving tray are fed out one by one. The two sides of a document sheet conveyed by the automatic document feeding means are conveyed to two image sensors disposed opposite to each other at a stable position with a stable depth of focus, and the images on both sides of the document are precisely read. It is an object of the present invention to provide an image reading apparatus which is excellent in stable transportability and enables the image reading.
[0014]
[Means for Solving the Problems]
Therefore, according to the present invention, the image of the document placed on the document placing position is read, and the document is conveyed by an automatic document feeder for feeding out the document sheets stacked on the document receiving tray one by one. An image reading device for reading images on both sides of a document sheet, a first image sensor for reading an image on one surface of the document sheet, and a second image sensor for reading an image on the other surface of the document sheet. When the first image sensor reads an image of the one side of the original sheet conveyed by the automatic document feeder at a predetermined reading position, the first image sensor reads the image of the original sheet at the reading position. A first platen for contacting and supporting the one surface and an image of the other surface of the document sheet conveyed by the automatic document feeder; A second platen for supporting the original sheet from the one surface side for reading by the second image sensor; and a first image sensor for placing the original placed at the predetermined original placement position on the first image sensor. And a third platen for contacting and supporting the placed original when reading while moving. The first platen and the second platen are arranged so as to be connected to each other. And the first platen and the third platen are connected and held together with the one holding member via an integral or separate fixing portion, and An image characterized in that the document contact surface of the first platen, the document contact surface of the second platen, and the document contact surface of the third platen form the same plane. Providing a reader
[0015]
Here, the first image sensor is configured by an optical reading device of a reduction optical system image sensor, and the second image sensor is configured by a close contact type image sensor of an equal-magnification optical system, The sensor and the first to third platens are unitized as a main unit, and the document receiving tray and the automatic document feeder are unitized as an upper unit, and the upper unit can be freely opened and closed by the main unit by a hinge. The operability at the time of reading a thick original such as a book is improved.
[0016]
The holding unit that holds the first platen and the second platen constitutes a part of a top surface of a housing of the main unit, and the holding unit and the fixing unit have An opening for receiving irradiation light from the first image sensor is formed, and the opening is formed so that the first platen is fitted therein.
[0017]
The first platen and the second platen are formed such that one platen is cut out in a stepped shape in a section of the connection portion in the document sheet conveyance direction, and formed in the connection direction. The other platen is engaged with the notched portion to connect the two plates to each other.
[0018]
Further, the first platen and the second platen are formed such that, in a cross section of the connection portion in the document sheet conveyance direction, both platens are cut out in steps having shapes opposite to each other, and are formed in the connection direction. The notches thus formed are connected to each other by fitting each other.
[0019]
The first platen and the second platen are rectangular bodies having the same thickness, and may be joined over the entire thickness of both platens.
[0020]
Further, the first platen and the second platen are formed such that one of them forms a convex ridge and the other forms a concave groove in the connecting direction at the connecting surfaces which are in contact with each other. It can also be connected by fitting the strip.
[0021]
The document receiving tray is provided above the third platen, and a document sheet conveyed by the automatic document feeder travels in a plane from the first platen to the second platen. You can also.
[0022]
Further, the present invention provides an image forming apparatus that includes the image reading device configured as described above and that forms an image based on the electric signal input from the image reading device.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings.
[0024]
FIG. 1 is a longitudinal sectional view for explaining an overall configuration of an image reading apparatus according to an embodiment of the present invention, and FIG. 2 is a state in which an upper unit of the image reading apparatus according to the embodiment is opened upward. FIG. 3 is an enlarged cross-sectional view of a main part in which the vicinity of the platens 6 and 7 in FIG. 1 is enlarged.
[0025]
1 and 2, reference numeral 1 denotes a main body unit, and an upper unit 2 is attached to the main body unit 1 by a hinge 33 so as to be freely opened and closed.
[0026]
The outside of the main unit 1 is formed by a housing 3, and a paper discharge tray 4 is fixed to one side surface of the housing 3. A third platen, which is a transparent glass plate on which a thick original such as a book for reading an image without moving the original is placed, is provided on the upper surface of the housing 3 on the side opposite to the discharge tray 4. 5 are incorporated. The fixing portion 3b, which is a part of the housing 3, is interposed and fixed between the third platen 5 and the first platen 6 which is a transparent glass plate. A second platen 7 formed of an opaque white member for supporting a document sheet is connected to the first platen 6.
[0027]
The upper surface 6a of the first platen 6 and the upper surface 7a of the second platen 7 are connected so as to be flush with each other, and both upper surfaces 6a, 7a also form the same plane as the upper surface of the third platen 5.
[0028]
The first platen 6 and the third platen 5 are connected to each other via a long fixing portion 3b. The long fixing portion 3b is a stepped portion cut in the longitudinal direction of the end. The first platen 6 is fitted with the third platen 5 by a concave groove 7c having a cross section which is also provided in the longitudinal direction. By providing a step portion and a groove width according to the thickness of each platen, the upper surfaces of the platens can be easily made the same plane.
[0029]
Further, the first platen 6 and the second platen 7 are notched and fitted to the end 7b of the second platen 7 with a step having the same thickness as the first platen 6 in the same manner as the fixing portion 3b. By fitting together, they can be connected to each other and the upper surface can be formed on the same plane.
[0030]
On the other hand, the other end of the second platen 7 is fitted and held by a step provided on the holding portion 3 a which is a part of the housing 3. Thus, an opening is formed above the first carriage 9 to receive the light emitted from the light source 11.
[0031]
A pair of discharge rollers 8 and 32 for discharging a document are provided at the lower end of the case 2 on the discharge tray 4 side. The discharge roller 8 is driven by a motor (not shown).
[0032]
Inside the housing 3, a reduction optical system image sensor (line sensor) for reading a document image and converting it into an electric signal is housed. Reference numerals 9 and 10 denote carriages which form a part of the reduction optical system image sensor, and are driven by motors (not shown) to move inside the housing 3 in the left-right direction in FIG. I do. The carriage 9 has a light source 11 for projecting irradiation light on the document at a fixed position or while moving, and receives a reflected light of the irradiation light projected by the light source 11 from the document and outputs a horizontal light beam. And a reflecting mirror 12 for changing the direction. The carriage 10 has a reflecting mirror 13 for turning the horizontal reflected light reflected from the reflecting mirror 12 into the vertical reflected light, and the vertical reflected light reflected by the reflecting mirror 13 as the reflected light. A reflecting mirror 14 that changes the direction of the reflected light in the horizontal direction opposite to the reflected light reflected from the mirror 12 is mounted.
[0033]
Reference numeral 15 denotes a condenser lens 15 for receiving reflected light from the reflecting mirror 14 and condensing the same. The light source 11, the reflecting mirrors 12 to 14, and the lens 15 form a reduction optical system image sensor. Reference numeral 16 denotes a line sensor 16 comprising a CCD for receiving the reflected light condensed by the lens 15 and converting it into an electric signal. A lead wire (not shown) is connected to an output end of the line sensor unit 16, and an image signal obtained by converting reflected light from the document as an electric signal through the lead wire into a copying machine or a facsimile machine (not shown) Is transmitted to the main body of the image forming apparatus.
[0034]
The outside of the upper unit 2 is formed by a housing 17, and a portion of the lower surface of the housing 17 corresponding to the platen 5 of the main unit 1 is softly pressed by a document placed on the platen 5. A pressing member 18 composed of a sponge member having elasticity for fixing and a surface mylar is fixed. Reference numeral 17a denotes a document receiving tray for stacking and placing document sheets. The document receiving tray 17a is formed so that the platen 6 side is lowered and inclined so that the document sheet moves to the first platen 6 side. At the end of the inclined surface of the document receiving tray 17a on the platen 6 side, a paper feed roller (not shown) for supplying the document sheet placed on the document receiving tray 17a onto the platen 6 is provided. The document sheet is conveyed to the opening 21 by the feed roller.
[0035]
Reference numeral 17a denotes a document receiving tray for stacking and placing documents to be conveyed one by one and reading an image. The document receiving tray 17a is formed with the platen 6 side lowered and inclined so that the document moves to the platen 6 side. At the end of the inclined surface of the platen 17a on the platen 6 side, a pair of paper feed rollers 19 and 22 sandwiching the platen 6 to supply the documents placed on the platen 17a one by one onto the platen 6 are provided. They are provided so as to be in contact with each other. At the intermediate portion between the opening 21 and the platen 6, a pair of sheet feeding rollers 40 and 23 are provided similarly to the sheet feeding rollers 19 and 22 for conveying the document inserted from the opening 21 onto the platens 6 and 7. I have. An original transport path 24 is formed between the paper feed rollers 19 and 22 and the paper discharge roller 8 via a pair of upper and lower plate bodies 45 and 46. The paper feed rollers 19 and 40 are driven by a motor (not shown).
[0036]
Reference numeral 48 denotes an upper guide for introducing a document sheet conveyed from the document receiving tray 17a into the conveyance path 24 and a stopper for stopping the introduction, and operates at the timing of reading and feeding. .
[0037]
In the contact type image sensor in the upper cover 20, a light source 25 for projecting irradiation light for reading an image on the back surface (upward facing surface) of the document conveyed in the conveyance passage 24, and the irradiation light And a protective glass 27 that transmits light reflected from the back side of the document sheet, a cell hook lens 26 for converting the reflected light into parallel light, and detects the light transmitted through the cell hook lens and converts the light into an electric signal. The line image sensor unit 28 and the circuit board 30 are integrally fixed as a compact image sensor (hereinafter referred to as CIS) unit 29. A plate-shaped backup guide 39 is integrally fixed to the CIS at a front end 39a in the transport direction and constitutes the CIS unit 29. The backup guide 39 is pivotally supported by a pair of rotating pins 31 protruding from the left and right side plates 42 of the upper lid 20, and the CIS unit 29 rotates about the rotating pin 31 as a fulcrum.
[0038]
One end of a pressing spring 34 for pressing the backup guide 39 downward is attached to the rear end 39 b of the backup guide 39 in the transport direction, and the other end of the spring is a spring protruding laterally from above the side plate 42. It is attached to a support member 49. As shown in FIG. 3, spacers 35 are fixed to the lower end portions of the CIS unit 29 on the side of the discharge rollers 8 and 32 at the left and right corners, and the spacers 35 come into contact with the second platen to back up. The distance between the transport path 24 between the lower surface of the CIS unit 29 composed of the guide 39 and the protective glass 27 and each of the platens 6 and 7 is adjusted so that each image sensor can receive a focused image at an appropriate distance. ing.
[0039]
In the image reading apparatus according to the present embodiment, a plurality of sensors (not shown) for detecting the position of the document and the presence or absence of an image on the document are provided, and based on a detection signal from the sensor, A control circuit (not shown) is provided for controlling operations such as a rotation driving operation of a motor (not shown), a movement operation of the carriages 9 and 10, a light emission operation of the light sources 11 and 25, and an output operation of the line sensor 16.
[0040]
Next, the operation of the present embodiment will be described.
[0041]
When the original sheets are supplied one by one to the reading unit to be copied or transmitted, these original sheets are stacked and placed on the original receiving tray 17a of the upper unit 2. These original sheets are inserted into the reading unit one by one from the opening 21 by a paper feed roller (not shown).
[0042]
In the reading section, the original sheet is supplied onto the first platen 6 through the conveyance path 24 by the paper feed rollers 22 and 23. At this time, the carriages 9 and 10 of the main unit 1 are at the leftmost stop positions in FIG. When the control circuit detects that the document has reached the platen 6 based on a detection signal from a document sensor (not shown), the control circuit applies the irradiation light from the light source 11 to the document sheet while the carriages 9 and 10 are stopped at the stop position. Flood light. This irradiation light passes through a platen 6 which is a transparent glass plate, is irradiated on the surface of the original sheet, is reflected on the surface of the original sheet to become reflected light, and is reflected by the lens 15 via the reflecting mirrors 12, 13, and 14. Incident. The reflected light incident on the lens 15 is focused on the line sensor 16 by the lens 15, and a reduced image on the front side of the document sheet is formed on the line sensor 16. The line sensor 16 transmits an electric signal corresponding to the reduced image to a main body of the image forming apparatus based on a control signal from the control circuit, and the main body of the image forming apparatus reproduces or reproduces an image based on the electric signal. Send.
[0043]
Next, the document sheet moves onto the platen 7. At this time, the platen 6 and the platen 7 are connected to each other, and the upper surface 6a of the platen 6 and the upper surface 7a of the platen 7 form the same plane. Transition smoothly. When the original sheet reaches the platen 7, the control circuit that detects that the original sheet has moved onto the platen 7 by a detection signal from a sensor (not shown) causes the light source (LED) 25 to emit irradiation light. The irradiation light emitted by the light source (LED) 25 passes through the protective glass plate 27 and is irradiated on the back surface of the document sheet. Irradiation light applied to the back surface of the document sheet is reflected by this back surface and becomes reflected light. This reflected light passes through the protective glass plate 27 again, becomes parallel light by the cell hook lens 26, and enters the CCD 28. The CCD 28 outputs an electric signal corresponding to the reflected light to the main body of the image forming apparatus under the control of the control circuit, and the main body of the image forming apparatus outputs the image of the back surface of the original sheet based on the electric signal. Play or send.
[0044]
The original sheet from which the front and back images have been read is discharged from the reading unit by the discharge roller 8 and is deposited on the discharge tray 4.
[0045]
In the method using the third platen, when an original is placed on the third platen 5 and an operation start switch (not shown) for instructing the start of a copy or transmission operation is pressed, a signal from a sensor (not shown) The control circuit that has detected that a document is present on the platen 5 based on the detection signal outputs a control signal instructing movement of the carriages 9 and 10, and moves the carriages 9 and 10 rightward in FIG. 1 by a motor (not shown). . The control circuit simultaneously transmits a control signal for instructing the light source 11 to project the irradiation light, and the light source 11 projects the irradiation light on the original surface on the platen 5 while moving to the right in FIG. Keep doing. Since the platen 5 is a transparent glass plate, the irradiation light from the light source 11 passes through the platen 5 and irradiates the original surface on the platen 5. The reflected light from the original surface passes through the platen 5 again, is reflected by the reflecting mirrors 12, 13, and 14 like the transmitted light from the platen 6, and is condensed on the line sensor 16 as a reduced image via the lens 15. Image. An electric signal corresponding to the reduced image is output from the line sensor 16, and the image forming apparatus reproduces or transmits the image of the document based on the electric signal.
[0046]
In the present embodiment, since the first platen 6 and the second platen 7 are connected so that the upper surfaces 6a and 7a thereof form the same plane, the original is vertically moved. The image is stably transferred from the platen 7 to the platen 6 without being shaken, and a highly accurate original image can be read on the platen 7 in the vertical direction.
[0047]
Further, it is possible to sufficiently secure a stable running property between the document surface at the document reading position on the front surface and the back surface of the document sheet and the reading surface of the image sensor, and to place the second image sensor above one carriage of the first image sensor. And the third platen, then the first platen, and finally the second platen in the document transport direction, to reduce the size of the apparatus, obtain fine image data of both sides of the document, and reduce the structure. A simple and compact reader could be formed. Further, since the document receiving tray 17a is located above the third platen 5 having no reading section at the top, the vertical shape can be reduced.
[0048]
Next, a first modification example of the first platen 6 and the second platen 7 of the present embodiment will be described with reference to FIG. The first platen 6 and the second platen 7 are rectangles having substantially the same shape and the same thickness, and their connecting portions are in contact with each other as vertical surfaces. The holding portion 3a that supports the second platen 7 from its bottom further extends toward the first platen 6, and partially supports the second platen directly from the bottom. The connection and fixation of the first platen 6 and the fixing portion 3b are the same as in the above embodiment.
[0049]
The operation of this modification is the same as the operation of the above embodiment. However, in this modification, the platen 6 and the platen 7 are fixed by merely abutting the ends, so that the second platen 7 does not need to be subjected to a special notch processing, and each platen 6 It is easier to manufacture and can improve production efficiency.
[0050]
Similarly, a second modification will be described with reference to FIG. 4 is different from the example of FIG. 4 in the connection portion between the first platen 6 and the second platen, and the cutout portion 6b of the connection side end of the first platen 6 and the connection side end of the second platen. The notches 7b of the parts are formed so as to form steps of opposite shapes and fit with each other, and the upper surfaces 6a and 7a of the platens 6 and 7 are attached so as to form the same plane. As compared with the second modification, the mechanical connection between the platens is more reliable.
[0051]
FIG. 6 is a cross-sectional view showing a third modification of the first and second platens. In the present modification, a concave groove 7d extending in the horizontal direction is formed at the connecting end of the first platen 6 at substantially the center in the thickness direction, and the connecting groove of the second platen 7 is also connected. At the side end, a ridge 6d is formed to fit with the groove 7d formed at the end of the first platen 6. The first and second platens are fixed by fitting the concave groove 7d and the ridge 6d, and are fixed so that their upper surfaces 6a and 7a form the same plane.
[0052]
The operation of this modification is the same as the operation of the above embodiment. However, in this modification, both platens are fitted and fixed as concave grooves 7d and convex ridges 6d at their ends, so that the mechanical coupling is strong. Even if the platen 6 and 7 vibrate violently, the upper and lower surfaces 6a and 7a of the platens 6 and 7 can always keep forming the same plane without blurring.
[0053]
In the above embodiment, the holding portion 3a for holding the second platen 7 and the first platen 6 and the fixing portion 3b for connecting and fixing the first platen 6 and the third platen 5 are separate from each other. Although described as a body, as a modified example of the holding portion 3a and the fixing portion 3b, as shown in a perspective view in FIG. 7, the holder 70 is configured as an integral body connected by their longitudinal ends 69. You can also. In this case, when attaching the first platen 6 and the second platen 7, these platens are previously mounted on the holder 70 and then fitted into the housing above the first image sensor, so that Mounting work is facilitated.
[0054]
As described in detail above, in the image reading apparatus according to the present invention, the first platen and the second platen are arranged so as to be connected to each other and are held via the holding unit. And the third platen are connected and held to each other via an integral or separate fixing part with the one holding member, and the original contact surface of the first platen and the original of the second platen The contact surface and the document contact surface of the third platen are configured to form the same plane, so that the stable reading within the depth of focus of the document sheet can be performed together with the precise reading of the placed document. As a result, it is possible to provide an image reading apparatus capable of reading images on both sides of a document precisely at the same time.
[0055]
Since such stable running is ensured, the present invention makes it possible to use a close contact type image sensor of the same magnification optical system as the second image sensor.
[0056]
Further, according to the present invention, one side (front side) of the document sheet is read by bringing both sides of the document sheet conveyed by the automatic document feeder into close contact with two image sensors arranged to face each other at a close position. And a reading position for reading the other side (back side) of the document sheet as close as possible without separating them, and forming a roller or a space between the first platen and the second platen. By forming the image reading apparatus in close contact and integrally, it is possible to provide an image reading apparatus capable of reading both sides of a small and lightweight original sheet.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view illustrating an overall configuration of an image reading apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view of the image reading apparatus according to the embodiment shown in FIG. 1 when the upper unit is opened upward, as viewed from the front of FIG. 1;
FIG. 3 is an enlarged sectional view of a main part of the embodiment shown in FIG. 1;
FIG. 4 is a cross-sectional view showing a first modified example of connection between platens.
FIG. 5 is a cross-sectional view showing a second modification of the connection between the platens.
FIG. 6 is a cross-sectional view showing a third modification of the connection between the platens.
FIG. 7 is a perspective view illustrating an example of a holder in which a holding unit and a fixing unit are integrated.
[Explanation of symbols]
1 Main unit
2 Upper unit
5 Platen (third platen)
6 Platen (first platen)
7 Platen (second platen)
9,10 carriage (first image sensor)
11 light source (first image sensor)
12, 13, 14 Reflector (first image sensor)
15 Lens (first image sensor)
20 top lid
25 Light source (second image sensor)
26 cell hook lens (second image sensor)
27 Protective glass (second image sensor)
28 Image sensor unit (second image sensor)
29 CIS unit (second image sensor)
33 Hinge
35 Spacer
39 Backup Guide

Claims (10)

The image on both the front and back sides of the original sheet conveyed by the automatic original feeding means for reading the image of the original placed on the original placing position and feeding out the original sheets stacked on the original receiving tray one by one. An image reading device for reading
A first image sensor for reading an image on one surface of the document sheet, a second image sensor for reading an image on the other surface of the document sheet, and a document fed by the automatic document feeder When the first image sensor reads the image on the one side of the original sheet at a predetermined reading position, the first image sensor contacts and supports the one side of the original sheet at the reading position. Platen,
A second platen for supporting the original sheet from the one surface side so that the second image sensor reads an image on the other surface of the original sheet conveyed by the automatic document feeder; ,
And a third platen for contacting and supporting the placed original when the first image sensor reads the placed original placed at the predetermined original placement position while moving. And
The first platen and the second platen are arranged so as to be connected to each other and are held via a holding unit, and the first platen and the third platen are connected to the one holding member and A document contact surface of the first platen, a document contact surface of the second platen, and a document contact surface of the third platen, which are mutually connected and held via an integral or separate fixing portion. Is an image reading device configured to form the same plane. The image reading apparatus according to claim 1, wherein the first platen is formed of a transparent member, and the second platen is formed of a white opaque member. The first image sensor, the first platen, the second platen, and the third platen are unitized as a main unit, and the document receiving tray, the automatic document feeder, and the second The image sensor is unitized as an upper unit,
The image reading apparatus according to claim 1, wherein the upper unit is attached to the main unit so as to be freely opened and closed by hinge means. The holding unit that holds the first platen and the second platen forms a part of a housing upper surface of the main body unit, and the first unit is provided between the holding unit and the fixing unit. 4. The image reading device according to claim 1, wherein an opening for receiving irradiation light from the image sensor is formed, and the first platen is fitted in the opening. The first platen and the second platen are formed such that one platen is cut out in a stepped shape in a section of the connection portion in the document sheet conveyance direction, and the first platen and the second platen are formed toward the connection direction. The image reading device according to claim 1, wherein the other platen is engaged with the notch, and is connected to each other. The first platen and the second platen are formed such that, in a cross section of the connection portion in the document sheet conveyance direction, both platens are cut out in a reverse step shape, and formed in the connection direction. The image reading apparatus according to claim 1, wherein the notch portions are connected to each other by being fitted to each other. The image reading device according to claim 1, wherein the first platen and the second platen are rectangular bodies having the same thickness, and are joined over the entire thickness of both platens. The first platen and the second platen have, on their connecting surfaces that face each other, one formed a ridge and the other formed a groove toward the connection direction, and the groove and the ridge The image reading apparatus according to claim 1, wherein the image reading apparatuses are connected by fitting. The document receiving tray is provided above the third platen, and the document sheet conveyed by the automatic document feeder travels in a plane from the first platen side to the second platen side. The image reading apparatus according to claim 1, wherein An image forming apparatus that includes an image reading device that reads an image of a document and converts the read image into an electric signal, and forms an image based on the electric signal input from the image reading device.
The image reading device,
A first image sensor for reading an image on one side of the document sheet,
A second image sensor for reading an image on the other side of the document sheet,
When the first image sensor reads an image on the one side of the document sheet conveyed by the automatic document feeder at a predetermined reading position, the first image sensor applies the image on the one side of the document sheet at the reading position. A first platen for contacting and supporting this;
A second platen for supporting the original sheet from the one surface side so that the second image sensor reads an image on the other surface of the original sheet conveyed by the automatic document feeder; ,
And a third platen for contacting and supporting the placed original when the first image sensor reads the placed original placed at the predetermined original placement position while moving. And
The first platen and the second platen are arranged so as to be connected to each other and held via one holding member, and the first platen and the third platen are connected to the one holding member. The members are connected and held to each other via an integral or separate holding member, and the document contact surface of the first platen, the document contact surface of the second platen, and the third An image forming apparatus configured to form the same plane as the original contact surface of the platen.

Images