JP3670478B2 - Document image reading device - Google Patents

Description

[0001]
[Field of the Invention]
The present invention relates to a document image reading apparatus mounted on a digital copying system or the like, and more specifically, while efficiently reading a first surface image and a second surface image on a document, The present invention relates to a document image reading apparatus provided with optical means that does not affect the other reading unit and cause no problem in image quality.
[0002]
[Prior art]
Conventionally, a document reading apparatus having a single document reading optical system (document reading unit) is generally known. However, since a document reading optical system is single, a document that can be read by a single scan. The surface is only one side of either the front surface or the back surface, and when reading information on both sides of the document, the operator has to invert the document and perform a reading operation for each side of the document.
[0003]
Also, after the original is automatically conveyed to the original reading unit, the original image information on one side is read by the original reading unit, the original side is automatically reversed, and the other side is conveyed again to the original reading unit. An apparatus capable of automatically reading images on both sides of an original by reading the original image has been proposed. However, the apparatus is generally expensive and requires a complicated mechanism.
[0004]
Furthermore, when the image information on both sides of the document is read by inverting the document with a single reading unit as described above, it is necessary to scan the document surface twice with the reading unit. There is a problem in that the processing time becomes long and the processing efficiency deteriorates.
[0005]
Accordingly, as a proposal for solving the above-mentioned problem, for example, in Japanese Patent Laid-Open No. 56-46260, two image reading devices provided to independently read image information on both sides of a document are provided. A document reading device is disclosed in which the image reading devices are arranged such that the position of the main scanning line on the surface does not match on both sides with respect to the sub-scanning direction of the document.
[0006]
In JP-A-6-103406, a first scanner unit having a reduction optical system for reducing an image on the surface of a form and a second scanner unit not requiring a reduction optical system are provided. A technique is disclosed in which both sides of a form can be read, the second scanner unit can be reduced in size, and the apparatus can be prevented from being enlarged by being placed close to the form.
[0007]
[Problems to be solved by the invention]
In Japanese Patent Laid-Open No. 56-46260, image information on both sides of a document can be read simultaneously by scanning the document in one direction, so that a reduction in processing efficiency can be prevented and each document surface can be read. This is effective in that the slits are provided so as to be shifted from each other in the sub-scanning direction so that the light source light for reading does not pass through the document and adversely affect the reading unit on the opposite side. It is a thing.
[0008]
However, in this publication, since it is necessary to displace the installation positions (slits) of the two image reading units, there is a problem that the apparatus becomes large, and there are restrictions on the setting positions of the two image reading units. Therefore, there arises a problem that the positional relationship of the mechanism cannot be freely set and the mechanism becomes complicated. Furthermore, if only the installation position of the image reading unit is shifted, the light source light for reading the document image transmitted through the paper may be irradiated to the other document reading unit by stray light.
[0009]
On the other hand, according to the technical content described in Japanese Patent Application Laid-Open No. 56-46260, a first scanner unit including a reduction optical system for reducing an image on the surface of a form and a reduction optical system are not required. By providing two scanner units, both sides of the form can be read, the second scanner unit can be miniaturized, and by placing it close to the form, the size of the apparatus can be prevented from being increased. It is effective.
[0010]
However, also in this publication, there is a possibility that the light source light for reading the original image that has passed through the original may be irradiated to the other original reading unit by stray light, and further, the reduced image cannot be obtained by the second scanner unit. There was a problem.
[0011]
The present invention has been made in view of the above problems, and includes two image reading devices provided to read image information on both sides of a document independently and simultaneously, and causes malfunction due to stray light from light source light. An object of the present invention is to provide a document image reading apparatus that has a simple mechanism and is easy to miniaturize.
[0020]
[Means for Solving the Problems]
A document image reading apparatus according to claim 1, wherein a first optical guide member for guiding an image surface of a document for reading a first surface side of the document;
A first light source that exposes a first surface of a document guided by the first optical guide member and a first imaging unit that forms a reflected light image from the document exposed by the first light source. Optical means,
A first document reading means comprising a first light receiving means for receiving a light image formed by the first optical means;
A second optical guide member disposed opposite to the first document reading means and guiding the image surface of the document in order to read the second surface side of the document;
A second light source that exposes a second surface of the document guided by the second optical guide member, and a second image forming unit that forms a reflected light image from the document exposed by the second light source; Optical means,
A second document reading means comprising a second light receiving means for receiving a light image formed by the second optical means,
The first or second surface of the document is in contact with the surface of the first or second optical guide member, respectively, and the document image is read.
The lower optical guide member is formed in a curved shape in which the downstream side in the document conveying direction is lowered,
A document image reading apparatus characterized in that a transport surface downstream of the document reading unit in the document transport direction is provided on a lower surface than a sheet transport path surface formed by the first and second optical guide members. is there.
[0021]
According to the present invention, the distance between the light receiving means and the original surface can be kept constant, and the reading accuracy of the original can be improved. Further, the transport surface downstream of the document reading unit in the document transport direction is provided on a surface lower than the sheet transport path surface formed by the first and second optical guide members. In this way, the simple structure of simply shifting the conveying surface can improve the document conveying path, and one surface of the document can be brought into contact with the surface of one document guiding optical member. In addition, the lower optical guide member is formed in a curved shape in which the downstream side in the document transport direction is lowered, so that one surface of the document can be smoothly brought into contact with the surface of one document guide optical member. Therefore, with a simple configuration, the distance between the light receiving means and the document surface can be made more reliable and the document reading accuracy can be further improved.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to FIGS.
Although only the case where the present invention is applied to the digital copying system is described as an explanation of the present embodiment, the present invention is not applied only to the digital copying system, and is a general apparatus including a document image reading apparatus. Needless to say, this is applicable.
[0038]
FIG. 1 shows a digital copying system 1 equipped with a document reading device according to the present invention. Since the document reading device 10 and the double-sided printer 30 are connected by a cable 60, the document reading device is arranged at an arbitrary place for use. Is possible. Here, the double-sided printer 30 will be described first.
[0039]
Image data obtained by reading a document image with the document reading device 10 is sent to an image processing unit, which will be described later, and after various processing, is temporarily stored in the memory of the image processing unit and responds to an output instruction. The image in the memory is read out and transferred to the double-sided printer unit 30 via the cable 60 to form an image on the recording sheet.
[0040]
The double-sided printer unit 30 includes a sheet conveyance system as a recording material for forming an image, a laser writing unit 46, and an electrophotographic process unit for forming an image.
[0041]
The laser writing unit 46 is a semiconductor laser light source that emits laser light (not shown) in accordance with image data read from the memory after being read by the document reading device 10 or image data transferred from an external device. A polygon mirror that deflects the laser beam at a constant angular velocity, and an f-θ lens that corrects the laser beam deflected at a uniform angular velocity to be deflected at a constant angular velocity on the photosensitive drum 48 constituting the electrophotographic process unit. ing.
[0042]
The electrophotographic process section includes a charging device, a developing device, a transfer device, a peeling device, a cleaning device, and a static eliminator around a known photosensitive drum 48.
[0043]
On the other hand, the conveyance system for the sheet P is a conveyance unit that conveys the sheet P to the transfer position in which the transfer unit is arranged in the electrophotographic process unit that performs the image formation described above, and for feeding the sheet P to the conveyance unit. Cassette paper feeding devices 51 and 52, a manual paper feeding device 54 for appropriately feeding sheets of a necessary size, a fixing device 49 for fixing an image formed on the sheet P after transfer, particularly a toner image, A refeeding path 53 for refeeding the sheet P to form an image again on the back surface of the sheet P after fixing is provided.
[0044]
A post-processing device 34 that receives a sheet P on which an image is recorded and performs a predetermined process on the sheet P is disposed downstream of the fixing device 49.
[0045]
In the laser writing unit 46 and the electrophotographic process unit, image data read from the image memory is formed as an electrostatic latent image on the surface of the photosensitive drum 48 by scanning the laser beam with the laser writing unit 46. The toner image visualized by the toner is electrostatically transferred and fixed on the surface of the paper conveyed from one of the paper feed units 51 and 52.
[0046]
The sheet P on which the image is formed in this way is conveyed from the fixing device 49 into the post-processing device 34.
[0047]
(Circuit explanation of image processing unit)
Next, the configuration and function of an image processing unit that performs image processing on the read document image information in the digital copying system 1 will be described.
[0048]
20 is a block diagram of an image processing unit included in at least one of the document reading device 10 and the duplex printer 30 of the digital copying system 1 of FIG.
[0049]
The image processing unit included in the digital copying system 1 includes an image data input unit 240, an image processing unit 241, an image data output unit 242, a RAM (random access memory), a memory 243 including a hard disk, and a central processing unit. A device (CPU) 244 is provided.
[0050]
The image data input unit 240 includes a CCD unit 240a, a histogram processing unit 240b, and an error diffusion processing unit 240c.
[0051]
The image data input unit 240 binarizes and converts the image data of the original read from the CCD 200, processes the image data by the error diffusion method while taking a histogram as a binary digital quantity, and temporarily stores it in the memory 243. Is configured to do.
[0052]
That is, in the CCD unit 240a, an analog electrical signal corresponding to each pixel density of the image data is A / D converted, and then MTF correction, black and white correction, or gamma correction is performed, and a 256 gradation (8 bits) digital signal is obtained. Is output to the histogram processing unit 240b.
[0053]
In the histogram processing unit 240b, the digital signal output from the CCD unit 240a is added for each pixel density of 256 gradations to obtain density information (histogram data), and the obtained histogram data is sent to the CPU 244 as necessary. In addition, it is sent to the error diffusion processing unit 240c as pixel data.
[0054]
In the error diffusion processing unit 240c, 8 bits / pixel output from the CCD unit 240a is obtained by an error diffusion method which is a kind of pseudo intermediate processing, that is, a method of reflecting a binarization error in binarization determination of adjacent pixels. The digital signal is converted to 1 bit (binarization), and redistribution calculation is performed to faithfully reproduce the local area density in the original.
[0055]
The image processing unit 241 includes multi-value processing units 241a and 241b, a synthesis processing unit 241c, a density conversion processing unit 241d, a scaling processing unit 241e, an image processing unit 241f, an error diffusion processing unit 241g, and a compression processing unit 241h. .
[0056]
The image processing unit 241 is a processing unit that finally converts the input image data into image data desired by the operator. The image processing unit 241 stores the output image data as final converted output image data in the memory 243. Configured to process. However, each of the above-described processing units included in the image processing unit 241 functions as necessary, and may not function depending on device specifications, setting conditions, and the like.
[0057]
Then, in the multilevel processing units 241a and 241b, the data binarized by the error diffusion processing unit 240c is converted back to 256 gradations.
[0058]
In the synthesis processing unit 241c, a logical operation for each pixel, that is, an operation of logical sum, logical product, or exclusive logical sum is selectively performed. The data to be subjected to this calculation is pixel data stored in the memory 243 and bit data from the pattern generator (PG).
[0059]
In the density conversion processing unit 241d, the relationship of the output density with respect to the input density is arbitrarily set based on a predetermined gradation conversion table for the data signal of 256 gradations.
[0060]
In the scaling processing unit 241e, pixel data (density value) for the target pixel after scaling is obtained by performing interpolation processing with input known data in accordance with the designated scaling factor, and sub-scanning is changed. After being doubled, the main scan is subjected to scaling processing.
[0061]
In the pixel process unit 241f, various image processes are performed on the input pixel data, and information collection for a data string such as feature extraction can be performed.
[0062]
The error diffusion processing unit 241g performs the same processing as the error diffusion processing unit 240c of the image data input unit 240.
[0063]
In the compression processing unit 241h, binary data is compressed by encoding called run length. As for the compression of the image data, the compression functions in the final processing loop when the final output image data is completed.
[0064]
The image data output unit 242 includes a restoration unit 242a, a multivalue processing unit 242b, an error diffusion processing unit 242c, and a laser output unit 242d.
[0065]
The image data output unit 242 restores the image data stored in the memory 243 in the compressed state, converts the image data back to the original 256 gradations, and generates an error in the quaternary data that is a smooth halftone expression than the binary data. It is configured to perform diffusion and transfer data to the laser output unit 242d.
[0066]
That is, the restoration unit 242a restores the image data compressed by the compression processing unit 241h, and the multilevel processing unit 242b performs the same processing as the multilevel processing units 241a and 241b of the image processing unit 241. In the error diffusion processing unit 242c, processing similar to that of the error diffusion processing unit 240c of the image data input unit 240 is performed.
[0067]
In the laser output unit 242d, the digital pixel data is converted into a laser on / off signal based on a control signal from a sequence controller (not shown), and the semiconductor laser in the laser writing unit 46 is turned on / off. An electrostatic latent image is written in
[0068]
The data handled in the image data input unit 240 and the image data output unit 242 are basically stored in the memory 243 in the form of binary data in order to reduce the storage capacity of the memory 243. It is also possible to process in the form of quaternary data in consideration of degradation of image data.
[0069]
(Explanation of the control configuration of the entire digital copying system)
FIG. 21 is a diagram showing a state in which the operation of each part of the entire apparatus of the digital copying system 1 is managed by the central control unit (CPU) 244.
[0070]
The CCD 200, image data input unit 240, image processing unit 241, image data output unit 242, image memory 243, and central processing unit (CPU) 244 overlap those in FIG.
[0071]
The central processing unit 244 manages each drive mechanism unit constituting the digital copying system 1 such as the RADF, the document reading device 10 and the printer unit 30 by sequence control and outputs a control signal to each unit.
[0072]
Further, an operation board unit 245 including an operation panel is connected to the central processing unit in a state where mutual communication is possible, and a control signal is transferred to the central processing unit 244 according to a copying mode set and input by the operator, and the mode is set. Accordingly, the digital copying system 1 is operated.
[0073]
Further, the central processing unit 244 transfers a control signal indicating the operation state of the digital copying system 1 to the operation board unit 245 so as to indicate to the operator what state the apparatus is currently in by this control signal. The operation state is displayed on a display unit or the like.
[0074]
The sorter control unit 246 is a control unit that manages the operation of the post-processing apparatus that sorts the copies output by the digital copying system 1, and the image data communication unit 247 is other digital information such as image information and image control signals. It is provided to enable information communication with image equipment.
[0075]
FIG. 22 shows the operation panel unit 175 in the digital copying system.
[0076]
A touch panel liquid crystal display device 106 is arranged at the center of the operation panel unit 175, and various mode setting keys are arranged around it.
[0077]
On the screen of the touch panel liquid crystal display device 106, there is a screen switching instruction area for switching to a screen for selecting an image editing function at all times, and various image editing functions can be selected by directly pressing the area with a finger. Various editing functions are displayed in a list on the LCD screen.
[0078]
Of the displayed various editing functions, the editing function is set by touching an area where a function desired by the operator is displayed with a finger.
[0079]
Briefly describing various setting keys arranged on the operation panel 175, a dial 107 for adjusting the brightness of the screen of the liquid crystal display device 106, and an automatic magnification setting key 108 for setting a mode for automatically selecting the magnification. There are provided a zoom key 109 for setting the copy magnification in 1% increments, fixed magnification keys 110 and 111 for reading out and selecting the fixed magnification, and an equal magnification key 112 for returning the copy magnification to the standard magnification (equal magnification). It is done.
[0080]
Also, a density switching key 113 for switching the copy density adjustment from automatic to manual or photo mode, a density adjustment key 114 for finely setting the density level in the manual mode or the photo mode, paper feeding of the copying machine A tray selection key 115 for selecting a desired paper size from the paper sizes set in the section is arranged.
[0081]
Further, a copy number setting key 116 for setting the number of copies, a clear key 117 operated when clearing the number of copies or stopping continuous copying halfway, a start key 118 for instructing the start of copying, and currently set There is an all cancel key 119 for canceling all the existing modes and returning to the standard state.
[0082]
Next, an interrupt key 120 that is operated when it is desired to copy another document during continuous copying, and an operation guide key 121 for displaying a message on the operation method of the copying machine by operating when the copying machine operation is unknown. , Message forward key 122 for displaying the continuation of the message displayed by operating the operation guide key 121, duplex mode setting key 123 for setting the duplex copying mode, and for sorting the copies ejected from the copying machine There is a post-processing mode setting key 124 for setting the operation mode of the post-processing apparatus.
[0083]
Also, there are setting keys 125 to 127 relating to the printer mode and the facsimile mode, a memory transmission mode key 125 for temporarily storing the transmission original in the memory and transmitting it, and for switching the mode of the digital copying system between copy, fax and printer. A copy / fax / printer mode switching key 126 and a one-touch dial key 127 for storing a destination telephone number in advance and making a call to the destination by one-touch operation during transmission are provided.
[0084]
It should be noted that the operation panel 175 and the various key groups arranged on the operation panel presented this time are merely illustrated as examples, and are provided on the operation panel 175 by various functions installed in the digital copying system 1. It goes without saying that the keys that are used are different.
[0085]
(Description of Embodiment of Image Reading Apparatus)
Hereinafter, the image reading apparatus 10 of the present invention will be described in more detail with reference to FIGS.
[0086]
(First embodiment of the present invention)
First, in the document reading apparatus 10 shown in FIGS. 1 and 2, the document 12 set on the sheet feeding tray 11 is drawn into the apparatus by sheet feeding rollers 13 and 14, and is constituted by, for example, polarizing filters 15a and 15b. Sent to the department.
[0087]
FIG. 5 is an enlarged view of the reading unit of the document reading apparatus 10 shown in FIG. 2, but these polarizing filters 15a and 15b have different polarization directions as shown in FIG.
[0088]
The light from the light sources 16a and 16b passes through the polarizing filters 15a and 15b, respectively, so that the directions of the light from the two light sources are different, and consideration is given so as not to affect the reading units opposite to each other. .
[0089]
Reference numerals 19a and 19b denote light source covers for preventing light from the light sources 16a and 16b from leaking to the outside.
[0090]
Reference numerals 17a and 17b are light receiving elements such as CCDs (photoelectric conversion elements), which project image information on the document onto the imaging surface by the imaging lenses 18a and 18b. Then, the document sent to the reading unit is accurately conveyed by a sub-scanning unit (not shown), and after the image information of the document is read, the document is discharged to the discharge tray 22 by the discharge rollers 20 and 21.
[0091]
The double-sided image data read as described above is sent to the image processing unit as described above, subjected to various processes, temporarily stored in the memory of the image processing unit, and stored in the memory according to the output instruction. Are transferred to the double-sided printer unit 30 via the cable 60 to form an image on the recording sheet.
[0092]
The document from which the data has been read is discharged from the reading unit by a paper transport unit (not shown), and is discharged to the paper discharge tray 22 by the paper discharge rollers 20 and 21.
[0093]
(Second embodiment of the present invention)
The document reading apparatus 10a shown in FIG. 3 includes documents having different wavelengths of light to be irradiated instead of the polarizing filters 15a and 15b, the light sources 16a and 16b, and the photoelectric conversion elements (CCD) 17a and 17b shown in FIG. By using exposure light sources 16c and 16d and photoelectric conversion elements (CCDs) 17c and 17d that are sensitive to the wavelength of light from each light source, consideration is given so as not to affect the reading units opposite to each other. . Other operations are the same as those of the document reading apparatus 10 in FIG.
[0094]
(Third embodiment of the present invention)
The original reading apparatus 10b shown in FIG. 4A transmits light having different wavelengths or wavelength ranges, instead of the polarizing filters 15a and 15b and the photoelectric conversion elements (CCD) 17a and 17b described in FIG. The optical filters 23e and 23f to be used and the photoelectric conversion elements (CCD) 17e and 17f having sensitivity to the wavelength of the light transmitted through each optical filter are used so as not to affect the reading units on the opposite sides. is there. Other operations are the same as those of the document reading apparatus 10 in FIG.
[0095]
(Fourth embodiment of the present invention)
The document reading device 10b ′ shown in FIG. 4B is for document exposure in which the wavelengths of light to be irradiated are different from each other, instead of the polarizing filters 15a and 15b and the photoelectric conversion elements (CCD) 17a and 17b described in FIG. Light sources 16c and 16d, optical filters 23e and 23f that transmit the light sources having different wavelengths or wavelength ranges, and general-purpose photoelectric conversion elements (CCDs) 17a and 17b, respectively, to the reading units opposite to each other. It is designed so as not to affect it. With this configuration, the degree of design freedom can be increased and the manufacturing cost can be reduced as compared with the photoelectric conversion element (CCD) having a relatively high component cost used in the third embodiment.
[0096]
In this example, the photoelectric conversion elements 17a and 17b used in the first embodiment, the light sources 16c and 16d used in the second embodiment, and the optical filters 23e and 23f used in the third embodiment are used. These components can be used in common, but they can also have different characteristics and may be set according to product specifications. Other operations are the same as those of the document reading apparatus 10 in FIG.
[0097]
(Fifth embodiment of the present invention)
In the document reading apparatus 10c shown in FIG. 6, one surface of the document 12 is brought into contact with at least one surface of the document guide optical members (optical guide members) 15g and 15h, and an image of the document is read. It is a thing. Other operations are the same as those of the document reading apparatus 10 in FIG.
[0098]
(Sixth embodiment of the present invention)
7 to 10 are enlarged views of the main internal part of the document reading apparatus 10. First, in FIG. 7, at least one of the document guide optical members 15i and 15j has a curved surface. Here, the upstream side as viewed from the conveying direction at the upper part of 15i has a curved surface shape.
[0099]
Further, the entire surface of one optical guide member with which the document comes into contact may be curved. For example, in the embodiment shown in FIG. 10, in the document guide optical members 150 and 15p, the entire surface of the optical guide member that comes into contact with at least one document comes into a curved shape. Other image reading operations are the same as those of the document reading apparatus 10 in FIG.
[0100]
(Seventh embodiment of the present invention)
In FIG. 8, a document guide member 25 for bringing the document into contact with at least one document guide optical guide member is provided on the document input side of the document guide optical members 15k and 151. The image reading operation is the same as that of the document reading apparatus 10 in FIG.
[0101]
(Eighth embodiment of the present invention)
In FIG. 9, the document guide optical members 15m and 15n are changed in shape to change the shape of at least one of the document guide optical members 15m and 15n so that the document is brought into contact with the document guide optical members 15m and 15n. It is.
[0102]
Here, the shape of the document guide member 15n is changed to have a structure that also functions as a document guide member. The other image reading operations are the same as those of the document reading apparatus 10 in FIG.
[0103]
(Ninth embodiment of the present invention)
In FIG. 7 and FIG. 10, Pal (solid line in the figure) indicates a document transport path. In these drawings, if the document is conveyed along the shape of the document guide optical members 15i and 150 with which the document is in contact, the document conveyance path is Pa2 (broken line in the drawing) in FIGS. However, by providing the sheet discharge rollers 20 and 21 below these conveyance path surfaces, the sheet conveyance surface of the sheet conveyance roller is provided below the sheet conveyance path surface formed by the optical guide member. The image reading operation is the same as that of the document reading apparatus 10 in FIG.
[0104]
(Tenth embodiment of the present invention)
In FIG. 8, 26 is a document guide optical member charging device, 26a and b are power supplies, and 26c and 26d are conductive glasses.
[0105]
When a voltage is applied from the power sources 26a and 26b, electric charges are supplied to the conductive glasses 26c and 26d, respectively, and an electric field is generated between the two conductive glasses to charge the document guide optical members 15k and 151.
[0106]
At this time, a force pulled in the direction from the document guide optical member 151 to 15 k acts on the object inserted between the document guide optical members 15 k and 151.
[0107]
Therefore, for example, the document sent to the reading unit including the document guide optical members 15k and 151 is adsorbed by the document guide optical member 15k, and the document that has passed through the region where the conductive glass is located is the document itself. It is conveyed without staying in the region due to its rigidity. Other image reading operations are the same as those of the document reading apparatus 10 in FIG.
[0108]
(Eleventh embodiment of the present invention)
In FIG. 11, 15q and 15r are original guide optical members made of, for example, an endless polarizing film, and 27a and 27b are drive mechanisms for the original guide optical member.
[0109]
In the document reading apparatus 10d, the document 12 set on the sheet feeding tray 11 is drawn into the apparatus by sheet feeding rollers 13 and 14, and is sent to a reading unit configured by, for example, endless polarizing films 15q and 15r. These endless polarizing films 15q and 15r have different polarization directions from each other, and can also carry a document.
[0110]
The light from the light sources 16a and 16b passes through the endless polarizing films 15q and 15 respectively, so that the directions of the light emitted from the two light sources are made different so as not to affect the reading units on the opposite sides.
[0111]
Reference numerals 17a and 17b denote photoelectric conversion elements such as CCDs, and image information of the original is projected onto the imaging surface by the imaging lenses 18a and 18b.
[0112]
Then, the original 12 sent to the reading unit is accurately conveyed by the endless polarizing films 15q and 15r, and discharged to the paper discharge tray 22 by the paper discharge rollers 20 and 21.
[0113]
The double-sided image data read as described above is sent to the image processing unit as described above, and after various processings, the image data in the memory is temporarily stored in the memory of the image processing unit in response to an output instruction. The data is read out and transferred to the double-sided printer unit via a cable.
[0114]
In FIG. 12, 15s is an original guide optical member made of, for example, an endless polarizing film, 15t is a polarizing filter, and 27c is a drive mechanism of the original guide optical member 15s.
[0115]
In the document reading apparatus 10e shown here, the document 12 set on the sheet feeding tray 11 is drawn into the apparatus by sheet feeding rollers 13 and 14, and is constituted by, for example, an endless polarizing film 15s or a polarizing filter 15t. Sent to the department. Here, the endless polarizing film 15s and the polarizing filter 15t have different polarization directions.
[0116]
The light from the light sources 16a and 16b passes through the endless polarizing film 15s and the light filter 15t, respectively, so that the directions of the light emitted from the two light sources are different and do not affect the reading units on the opposite sides. consider. Here, 17a and 17b are photoelectric conversion elements such as CCDs, and image information of the original is projected onto the imaging surface by the imaging lenses 18a and 18b.
[0117]
Then, the document fed to the reading unit is accurately conveyed by the endless polarizing film 15 s and is discharged to the discharge tray 22 by the discharge rollers 20 and 21.
[0118]
The double-sided image data read as described above is sent to the image processing unit as described above, and after various processings, the image data in the memory is temporarily stored in the memory of the image processing unit in response to an output instruction. The data is read out and transferred to the double-sided printer unit 30 via a cable.
[0119]
In FIG. 11, reference numeral 26 denotes an original guide optical member charging device, reference numerals 26a and 26b denote power sources, and reference numerals 26c and 26d denote conductive glass.
[0120]
When a voltage is applied from the power supplies 26a and 26b, electric charges are supplied to the conductive glasses 26c and 26d, respectively, and an electric field is generated between the two conductive glasses to charge the document guide optical members 15q and 15r.
[0121]
At this time, a force that is pulled in the direction of the document guide optical members 15q and 15r acts on the object that has entered between the document guide optical members 15q and 15r.
[0122]
Accordingly, for example, the document sent to the reading unit constituted by the document guide optical members 15q and 15r is adsorbed by the document guide optical member 15q and the document that has passed through the region where the conductive glass is located Due to the rigidity of the document itself, it is conveyed without staying in the area.
[0123]
The other image reading operations are the same as those of the document reading apparatus 10d in FIG. FIG. 5 is an enlarged view of the vicinity of the document guide optical members 15k and 151 in FIG.
[0124]
(Twelfth embodiment of the present invention)
In FIG. 13, 28 is a document charging device, 28a is a power source, 28b is a voltage adjusting device, and 28c is a document charging brush.
[0125]
When a voltage is applied from the power supply 28a, the voltage is adjusted by the voltage adjusting device 28b, and a current is applied to the document 12a through the document charging brush 28c. At this time, the original 12a is in a charged state. When the original 12a is inserted between the original guide optical members 15k and 151, an electric field is generated and the original 12a is drawn to one of the original guide optical members. , (See arrow in the figure), it is attracted to the document guide optical member 15k. The other image reading operations are the same as those of the document reading apparatus 10 in FIG.
[0126]
(Thirteenth embodiment of the present invention)
In FIG. 14, first, a current is applied to the document 12b by a document charging device (not shown) to be charged to a positive or negative charge, and the document guide optical member 15k is replaced with the document 12b by a document guide optical member charging device (not shown). Charge to the opposite charge.
[0127]
When a document is inserted between the document guide optical members 15k and 151 in this state, an electric field is generated to draw the document 12b toward the document guide optical member 15k (see the arrow in the figure), and the document guide optical member Adsorbed to 15k. The other image reading operations are the same as those of the document reading apparatus 10 in FIG.
[0128]
(Fourteenth embodiment of the present invention)
In FIG. 15, first, a current is applied to the document 12c by a document charging device (not shown) to be charged to a positive or negative charge, and the document guide optical member 151 is the same as the document 12c by a document guide optical member charging device (not shown). Charge to the charge.
[0129]
When a document is inserted between the document guide optical members 15k and 151 in this state, an electric field is generated, the document is drawn toward the document guide optical member 15k (see the arrow in the figure), and the document guide optical member 15k. To be adsorbed. The other image reading operations are the same as those of the document reading apparatus 10 in FIG.
[0130]
(Fifteenth embodiment of the present invention)
In FIG. 16, first, a current is applied to the document 12d by a document charging device (not shown) to be charged to a positive or negative charge, and the document guide optical member 15k is replaced with the document 12d by a document guide optical member charging device (not shown). Are charged to different charges, and the document guide optical member 151 is charged to the same charge as the document 12d by a document guide optical member charging device (not shown).
[0131]
When the original 12d is inserted between the original guide optical members 15k and 151 in this state, an electric field is generated to draw the original toward the original guide optical member 15k (see the arrow in the figure), and the original guide optical member Adsorbed to 15k. The other image reading operations are the same as those of the document reading apparatus 10 in FIG.
[0132]
(Sixteenth embodiment of the present invention)
In FIG. 17, reference numeral 29 denotes a document neutralizing brush. A document 12 e charged with a document charging device (not shown) that has been read is discharged from a reading unit by a sheet transport unit (not shown) and discharged by discharge rollers 20 and 21. Although discharged to the paper tray 22, the charge accumulated on the document 12 e is discharged by the document discharging brush 29 before the document arrives at the discharge rollers 20 and 21. The other image reading operations are the same as those of the document reading device 10d shown in FIG.
[0133]
(Seventeenth embodiment of the present invention)
The document reading device 10f shown in FIG. 18 can be divided into a one-side document reading device 10g containing one document reading means and a one-side document reading device 10h containing the other document reading means. is there.
[0134]
When divided and used, for example, the book original B can be placed directly on the original guide optical member 15u as shown in the figure to perform an image reading operation (one side only).
[0135]
Of course, the one-side document reading device 10g containing one document reading means and the one-side document reading device 10h containing the other document reading means can be integrated to perform the simultaneous reading operation on both sides of the document as shown in FIG. is there.
[0136]
(Eighteenth embodiment of the present invention)
In FIG. 19, 15w is an original guide optical member made of, for example, an endless polarizing film, 15x is a polarizing filter, and 27d is a drive mechanism for the original guide optical member 15w.
[0137]
The document reading device 10i shown here can be divided into a one-side document reading device 10g having one document reading means and a one-side document reading device 10h having the other document reading means.
[0138]
When divided and used, for example, the book original B can be placed directly on the original guide optical member 15x as shown in the figure to perform an image reading operation (one side only). Of course, the one-side document reading device 10i containing one document reading means and the one-side document reading device 10j containing the other document reading means can be integrated to perform the simultaneous reading operation on both sides of the document as shown in FIG. is there.
[0145]
【The invention's effect】
According to the present invention, two optical guide members are provided, and one surface of the document is brought into contact with the surface of one of the optical guide members to read the image of the document. Therefore, with this configuration, the distance between the light receiving means and the original surface can be kept constant, so that the reading accuracy of the original can be improved. Further, the transport surface downstream of the document reading unit in the document transport direction is provided on a surface lower than the sheet transport path surface formed by the first and second optical guide members. In this way, the simple structure of simply shifting the conveying surface can improve the document conveying path, and one surface of the document can be brought into contact with the surface of one document guiding optical member. In addition, the lower optical guide member is formed in a curved shape in which the downstream side in the document transport direction is lowered, so that one surface of the document can be smoothly brought into contact with the surface of one document guide optical member. Therefore, with a simple configuration, the distance between the light receiving means and the document surface can be made more reliable and the document reading accuracy can be further improved.
[Brief description of the drawings]
FIG. 1 is a diagram showing an entire digital copying system 1 according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view illustrating a document image reading apparatus 10 according to an embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a document image reading apparatus 10 according to an embodiment of the present invention.
FIG. 4 is a cross-sectional view illustrating a document image reading apparatus 10 according to an embodiment of the present invention.
FIG. 5 is an enlarged view of a main part in which a reading unit of the document image reading apparatus 10 according to the embodiment of the present invention is enlarged.
FIG. 6 is a cross-sectional view showing a document image reading apparatus 10 according to an embodiment of the present invention.
FIG. 7 is an enlarged view of a main part of the document image reading apparatus 10 according to the embodiment of the present invention.
FIG. 8 is an enlarged view of a main part of the document image reading apparatus 10 according to the embodiment of the present invention.
FIG. 9 is an enlarged view of a main part of the document image reading apparatus 10 according to the embodiment of the present invention.
FIG. 10 is an enlarged view of a main part of the document image reading apparatus 10 according to the embodiment of the present invention.
FIG. 11 is a cross-sectional view showing a document image reading apparatus 10 according to an embodiment of the present invention.
FIG. 12 is a cross-sectional view showing a document image reading apparatus 10 according to an embodiment of the present invention.
FIG. 13 is an enlarged view of a main part in the vicinity of the document guide optical members 15k and 15l according to the embodiment of the present invention.
FIG. 14 is an enlarged view of a main part in the vicinity of the document guide optical members 15k and 15l according to the embodiment of the present invention.
FIG. 15 is an enlarged view of a main part in the vicinity of the document guide optical members 15k and 15l according to the embodiment of the present invention.
FIG. 16 is an enlarged view of a main part in the vicinity of the document guide optical members 15k and 15l according to the embodiment of the present invention.
FIG. 17 is an enlarged view of a main part in the vicinity of the document guide optical members 15k and 15l according to the embodiment of the present invention.
FIG. 18 is an explanatory diagram showing that the document reading unit of the document image reading apparatus 10 according to the embodiment of the present invention is divided.
FIG. 19 is an explanatory diagram showing that the document reading unit of the document image reading apparatus according to the embodiment of the present invention is divided.
FIG. 20 is a block diagram of an image processing unit in the digital copying system 1 according to the embodiment of the present invention.
FIG. 21 is a diagram showing a state in which each part of the entire apparatus of the digital copying system 1 according to the embodiment of the present invention is managed by the central control system 44;
FIG. 22 is a diagram showing an operation panel of the digital copying system according to the embodiment of the present invention.
[Explanation of symbols]
10 Document Image Reading Device
11 Paper tray
12 Manuscript
13 Paper feed roller
15a, 15b Polarizing filter
16a, 16b Light source
17a, 17b photoelectric conversion element
18a, 18b Imaging lens
19a, 19b Light source cover
20, 21 Discharge roller
22 Output tray

Claims (1)

A first optical guide member for guiding an image surface of the document in order to read the first surface side of the document;
A first light source that exposes a first surface of a document guided by the first optical guide member and a first imaging unit that forms a reflected light image from the document exposed by the first light source. Optical means,
A first document reading means comprising a first light receiving means for receiving a light image formed by the first optical means;
A second optical guide member disposed opposite to the first document reading means and guiding the image surface of the document in order to read the second surface side of the document;
A second light source that exposes a second surface of the document guided by the second optical guide member, and a second image forming unit that forms a reflected light image from the document exposed by the second light source; Optical means,
A second document reading means comprising a second light receiving means for receiving a light image formed by the second optical means,
The first or second surface of the document is in contact with the surface of the first or second optical guide member, respectively, and the document image is read.
The lower optical guide member is formed in a curved shape in which the downstream side in the document conveying direction is lowered,
2. A document image reading apparatus according to claim 1, wherein a transport surface downstream of the document reading unit in the document transport direction is provided on a lower surface than a sheet transport path surface formed by the first and second optical guide members.

Images