JPH0955827A - Image reading apparatus, manufacturing method thereof, and image forming apparatus having the image reading apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copying device low in assembling cost, capable of accurately matching the light receiving surface of a CCD reader with the focus position of an image forming lens and hardly causing blooming and magnification errors, etc. SOLUTION: The image read part of the copying device is arranged between the image forming lens 23 and a CCD image sensor 24 and is provided with an optional path length adjusting plate 28 for optically matching a position where light is image-formed by the image forming lens 23 and the position of the light detection surface of the CCD image sensor 24. The optical path length adjusting plate 28 is provided with prescribed thickness and refractive index, is arranged at least between the CCD image sensor 24 and the image forming lens 23 and optically corrects the position of the light receiving surface of the CCD image sensor 24 to the position where reflected light from an original is focused based on a focusing property given to the reflected light from the original by the image forming lens 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming an image corresponding to image data by an electrostatic copying process and outputting the image on a sheet.

[0002]

2. Description of the Related Art An image forming apparatus using an electrostatic copying process, for example, an electrophotographic copying apparatus, stores a document holding unit for holding a document to be copied, and image information of the document held by the document holding unit. It has an image reading unit for taking out as light and dark information of light, an image forming unit for forming an image corresponding to the image information read by the image reading unit, and then outputting the image on a sheet.

The document holding section has, for example, a document table formed of a glass plate or the like, and a document scale which indicates a position where a document to be copied is to be placed. The image reading unit includes an illumination lamp that illuminates an original set on an original table, a CCD reading device that photoelectrically converts reflected light from the original illuminated by the illumination lamp into an electrical signal corresponding to image information, and It has an image forming lens device for making reflected light from the original document enter the light receiving surface of the CCD reading device in a stable state. From the manuscript to C
The reflected light traveling toward the CD reading device is generally bent multiple times by a plurality of mirrors arranged between the document table and the CCD reading device for the purpose of reducing the installation area of the device, and then the light receiving surface of the CCD reading device. Will be guided to.

The image forming unit includes a photoconductor that holds an electrostatic latent image corresponding to an image of a document read by a CCD reading device, a charging device that charges the photoconductor to a predetermined voltage, and a photoconductor charged by the charging device. Image exposure device for irradiating image information light for forming electrostatic latent image on body, developing device for developing by supplying developer to electrostatic latent image formed on photoconductor by image exposure device, developing device The transfer device is configured to transfer the developer image formed on the photoconductor to the paper as the image output material, and the paper feeding mechanism that feeds the paper toward the transfer device. The developer image transferred onto the paper through the transfer device is melted by being heated by the fixing device, and is fixed on the paper by the pressure from the fixing device.

By the way, in the image reading section, a method of converting the image information of the original into image data by forming an image of the reflected light of the original set on the original table on the light receiving surface of the CCD reading device by the image forming lens is widely used. It's being used.

However, each of the optical members used in the image reading section has a thickness of the platen glass, a refractive index of the imaging lens, a thickness of a plurality of mirrors or a mounting position of the CCD reading device and a light receiving surface. There is a component tolerance represented by the distance between them. Further, even if the accuracy of the individual component is sufficiently enhanced so that the component tolerance can be ignored, for example, the mounting position of each mirror, the distance between the document table and the imaging lens, or the imaging lens and the CCD. Due to the influence of the assembly error typified by the distance between the light receiving surface of the reading device, etc., the position of the imaging lens or It is well known that the position of the CCD reading device must be finely adjusted. By the way, in an image reading unit used in this type of copying apparatus, usually, the distance between the document table and the imaging lens and the distance between the imaging lens and the CCD are 1.
It is formed in a reduction optical system which is about 0 times.

Therefore, for example, moving either or both of the image forming lens and the CCD reading device to secure predetermined optical characteristics has a problem that it requires a high degree of skill and enormous adjustment time. Especially CCD
A slight change in the position of the reading device or a tilt with respect to the optical axis is approximately 10 times between the imaging lens and the platen.
Since it is increased to (the reciprocal of the reduction ratio of the optical system), the movable amount of the CCD reading device is actually limited to a limited narrow range. This greatly increases the assembly cost of the copying machine.

[0008]

As a countermeasure against the above-mentioned problems, an example of using a CCD unit in which the imaging lens and the CCD reading device are fixed in advance based on the focal length of the imaging lens is proposed. ing.
However, even when such a CCD unit is used, C is affected by the thickness of the platen glass and the mirror and the error in the respective mounting positions.
There is an unavoidable problem that fine adjustment of the position of the CD unit is required.

Further, in the actual adjustment, the imaging magnification on the light receiving surface of the CCD reading device (hereinafter referred to as magnification) and the exact matching of the light receiving surface of the CCD reading device with the focus position of the imaging lens (hereinafter, It is not uncommon for some of the optical characteristics to be sacrificed by keeping either one or both of them) within a predetermined allowable value. Regarding the reduction scale, there has been proposed a method of electrically correcting the error by thinning out a part of the output signal from the CCD reading device to reduce it or forming an interpolation signal from adjacent outputs to enlarge it. However, there is a problem that the image quality is degraded. In addition, when the focus tolerance is moderate (the tolerance range is wide), a CCD reading device with high resolution, that is, high resolution is required in order to prevent image blurring, which further reduces the cost of the device. There is a growing problem.

An object of the present invention is to accurately match the light receiving surface of a CCD reading device with the focal position of an imaging lens,
An object of the present invention is to provide an image reading apparatus which has a low assembly cost and is less likely to cause a defocus and a magnification error.

[0011]

The present invention has been made on the basis of the above problems, and is an image forming means for forming image information of an original document supported by the original document supporting means at a predetermined position as light and dark of light. And an image reading means for converting image information of an original image formed at a predetermined position by the image forming means into an electric signal corresponding to light and shade of light, and arranged between the image forming means and the image reading means. An image reading apparatus is provided which has an optical path length matching means for optically matching the position where light is imaged by the image forming means and the position of the light detection surface of the image reading means.

According to the invention, the illumination means for illuminating the original document supported by the original document supporting means and the image corresponding to the image of the original document by photoelectrically converting the reflected light from the original document illuminated by the illumination means. An image reading unit that outputs a signal, an image forming unit that forms an image of reflected light from a document illuminated by the illuminating unit on the image reading unit, a predetermined thickness and a refractive index, and at least the image. The image reading unit is arranged between the reading unit and the image forming unit, and the reflected light from the document is focused on the position where the reflected light from the document is focused based on the focusing property given to the reflected light from the document by the image forming unit. An image reading device having an optical path length adjusting means for optically correcting the position of the means is provided. Further, according to the present invention, the illumination means for illuminating the original document supported by the original document supporting means, and the reflected light from the original document illuminated by the illumination means are photoelectrically converted to output the image signal corresponding to the image of the original document. Image reading means, an image forming means for forming reflected light from a document illuminated by the illuminating means on the image reading means, and having a predetermined thickness and refractive index, the image reading means and the image reading means. Reflection from the original is provided on either or both of the image forming means and between the image forming means and the document supporting means, and based on the converging property given to the reflected light from the original by the image forming means. There is provided an image reading apparatus having an optical path length matching unit that optically corrects the position of the image reading unit with respect to the position where the light is focused.

Further, according to the present invention, the image information of the original document supported by the original document supporting means is imaged at a predetermined position as light and darkness of light, and the image formation means allows the image information to be formed at a predetermined position. An image reading unit for converting image information of an image of an original to be converted into an electric signal corresponding to light and shade of light, and is arranged between the image forming unit and the image reading unit, and the light forms an image by the image forming unit. The optical path length matching means for optically matching the position to be detected with the position of the light detection surface of the image reading means, the image forming means, the image reading means, and the optical path length matching means are held in a predetermined positional relationship. And an image reading device having a holding unit for performing the same.

Furthermore, according to the present invention, the image information of the original document supported by the original document supporting device is imaged at a predetermined position as the light and darkness of the light, and the image forming device is provided at a predetermined position. An image reading means for converting image information of an image of a document to be formed into an electric signal corresponding to light and shade of light, and a rear principal point of the image forming means, which is arranged between the image forming means and the image reading means. And the distance between the image reading means and L2,
When the focal length of the image forming unit is f and the magnification is m, the position where the image is formed by the image forming unit and the position of the light detection surface of the image reading unit are L2 = (m + 1) f + { An optical path having a thickness d satisfying (n-1) / n} d and optically aligning a position where light is imaged by the image forming unit and a position of a light detection surface of the image reading unit. An image reading device having a long alignment means is provided.

Furthermore, according to the present invention, the image information of the original document supported by the original document supporting means is imaged at a predetermined position as light and darkness of light, and the image formation means allows the image information to be formed at a predetermined position. An image reading unit for converting image information of an image of an original to be converted into an electric signal corresponding to light and shade of light, and is arranged between the image forming unit and the image reading unit, and the light forms an image by the image forming unit. In an image reading apparatus having an optical path length matching means for optically matching the position to be detected and the position of the light detection surface of the image reading means, the image is output corresponding to the image of the original document supported by the document supporting means. There is provided a method of manufacturing an image reading apparatus, characterized in that at least one of the refractive index and the thickness of the optical path length adjusting means is changed so that an output signal from the image reading means matches a predetermined waveform.

Furthermore, according to the present invention, the document supporting means for supporting the document, the illuminating means for illuminating the document supported by the document supporting means, and the reflected light from the document illuminated by the illuminating means. Image reading means for photoelectrically converting and outputting an image signal corresponding to the image of the original, image forming means for forming the reflected light from the original illuminated by the illumination means on the image reading means, and a predetermined thickness. Light having a high refractive index and a refractive index, is disposed between at least the image reading unit and the image forming unit, and reflects light from the document based on the converging property given to the reflected light from the document by the image forming unit. And an electrostatic latent image corresponding to the image information read by the image reading device and an optical path length matching device for optically correcting the position of the image reading device with respect to the position where An image bearing member for holding an image forming apparatus is provided with a developing means for developing by supplying a developer to the electrostatic latent image carried by the image carrier.

Further, according to the present invention, the document supporting means for supporting the document, the illuminating means for illuminating the document supported by the document supporting means, and the reflected light from the document illuminated by the illuminating means. Image reading means for photoelectrically converting and outputting an image signal corresponding to the image of the original, image forming means for forming the reflected light from the original illuminated by the illumination means on the image reading means, and a predetermined thickness. And having a refraction index and arranged at either or both of the image reading unit and the image forming unit and between the image forming unit and the document supporting unit, and is reflected by the image forming unit from the document. An image reading apparatus having an optical path length matching unit for optically correcting the position of the image reading unit with respect to the position where the reflected light from the original is focused based on the focusing property given to the light, and the image reading unit. Forming an image bearing member that holds an electrostatic latent image corresponding to the image information read by the image bearing unit, and a developing unit that supplies a developer to the electrostatic latent image held by the image bearing member to develop the image. A device is provided.

Further, according to the present invention, a document supporting means for supporting the document, and an image forming means for forming image information of the document supported by the document supporting means at a predetermined position as light and dark of light. An image reading unit for converting image information of an original image formed at a predetermined position by the image forming unit into an electric signal corresponding to light and darkness of light, and arranged between the image forming unit and the image reading unit. An optical path length matching means for optically matching a position where light is imaged by the image forming means and a position of a light detection surface of the image reading means, the image forming means, the image reading means and the optical path length An image reading device having a holding device that holds the matching device in a predetermined positional relationship, an image carrier that holds an electrostatic latent image corresponding to the image information read by the image reading device, and the image carrier. To the electrostatic latent image held by Image forming apparatus is provided with a developing means for developing by supplying agent.

As described above, the image reading device of the image forming apparatus of the present invention is arranged between the image forming means and the image reading means, and the position where the image is formed by the image forming means and the image reading means. It has an optical path length matching means for optically matching the position of the light detection surface.

The optical path length matching means has a predetermined thickness and refractive index, is arranged at least between the image reading means and the image forming means, and has a focusing property given to the reflected light from the original by the image forming means. Based on this, the position of the image reading means is optically corrected with respect to the position where the reflected light from the original is focused.

Further, the optical path length matching means has a predetermined thickness and refractive index, and is arranged between the image reading means and the image forming means and between the image forming means and the document supporting means or both. The position of the image reading means is optically corrected with respect to the position where the reflected light from the original is focused based on the focusing property given to the reflected light from the original by the image forming means.

Further, the optical path length matching means is arranged between the image forming means and the image reading means, the distance between the principal point on the rear side of the image forming means and the image reading means is L2, and the focus of the image forming means. When the distance is f and the magnification is m, the position where the image is formed by the image forming unit and the position of the light detection surface of the image reading unit are L2 =
Thickness d satisfying (m + 1) f + {(n-1) / n} d
And optically aligns the position where the light is imaged by the image forming means and the position of the light detection surface of the image reading means.

Therefore, the position of the light detecting surface of the image reading means can be optically matched with the focus position provided by the image forming means in a short time without requiring a high degree of skill.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. As shown in FIG.
Image forming apparatus or electrophotographic digital copying apparatus 2
Has an image reading unit 4 that functions as a reading unit and an image forming unit 6 that functions as an image forming unit. In addition, an upper portion of the image reading unit 4 is formed so as to be openable and closable with respect to a document table of the image reading unit 4 which will be described later. An automatic document feeder (hereinafter referred to as an AD) that functions as a document retainer for closely contacting a document D placed on the document table with the document table.
8) is set.

The image reading unit 4 is arranged on one side of the document table 11 and a document table 11 made of transparent glass on which the document D is set, facing the ADF 8 in the closed state. 11 has a reference display device 12 indicating the position where the document D is to be set. A control panel, which will be described later with reference to FIG. 3, is arranged near the document table 11 surrounding the document table 11.

Below the document table 11, the image reading section 4 is provided with an exposure lamp 13 for illuminating the document D placed on the document table 11, and for collecting light from the exposure lamp 13 on the document D. The auxiliary reflection plate 14 and the first mirror 15 that bends the reflected light from the document D to the left in the drawing are arranged. Exposure lamp 13, auxiliary reflector 14 and first
The mirror 15 is fixed to the first carriage 16,
The first carriage 16 is arranged so as to be movable in parallel with the document table 11 with the movement of the first carriage 16. The driving force of a pulse motor (not shown) is transmitted to the first carriage 16 via a toothed belt (not shown), and the first carriage 16 is moved in parallel along the document table 11.

In the left side of the document table 11 in the direction in which the reflected light reflected by the first mirror 15 is guided, it is parallel to the document table 11 via a drive mechanism (not shown) such as a toothed belt and a DC motor. A second carriage 20 is arranged so as to be movable.

The first carriage 15 is attached to the second carriage 20.
The second mirror 21 that bends the reflected light from the document D guided by and downward and the third mirror 22 that bends the reflected light to the right in the drawing are arranged at right angles to each other. Second carriage 2
0 is driven by the first carriage 16 by a toothed belt (not shown) for driving the first carriage 16 and is moved in parallel along the document table 11 at a speed of ½ with respect to the first carriage 16. It

The light reflected from the second carriage 20 is imaged at a predetermined magnification in the plane below the first carriage 16 and including the optical axis of the light reflected by the second carriage 20. An image forming lens 23 and a CCD image sensor 24 that converts the reflected light, which is focused by the image forming lens 23, into an electric signal, that is, image data are arranged. The imaging lens 23 and the CCD image sensor 24 are used as the CCD unit 26 in the optical base 26.
It is fixed integrally to a. Therefore, the distance L2 between the imaging lens 23 and the CCD image sensor 24, which will be described later with reference to FIG. 3, is generally fixed at a predetermined distance. Further, the CCD image sensor 24 is the optical base 2
Since it is fixed to the predetermined position of 6a, the inclination with respect to the optical axis is prevented from changing.

The image forming section 6 is a photosensitive drum 3 as an image bearing member rotatably positioned in the center of the copying apparatus 2.
It has 0. The photoconductor drum 30 is rotated at a predetermined rotation speed by a motor (not shown).

A predetermined position around the photosensitive drum 30 corresponds to a charger 31 for charging the surface of the drum to a predetermined charge, and image data supplied from an image processing unit described later, that is, image information to be image-formed. A laser beam generated from a laser diode (not shown) is deflected in the axial direction of the photosensitive drum 30 by a polygon mirror 32a as a deflecting device, and at the same time, the first and second folding mirrors 32b and 32c and the fθ lens 3 are provided.
A laser exposure device 32 that forms an electrostatic latent image on the surface of the photoconductor drum 30 by exposing the surface of the photoconductor drum 30 through 2d, and the surface of the photoconductor drum 30 is exposed by the laser exposure device 32. A developing device 33 having a developing roller 33a for supplying a toner as a developer to the formed electrostatic latent image to develop the electrostatic latent image at a desired image density, and a transfer material, that is, a copy sheet P fed from a sheet cassette described later.
The toner image formed on the photosensitive drum 30 is transferred to the photosensitive drum 30 and the sheet P on which the toner image is transferred is transferred to the photosensitive drum 30.
Transfer / separation charger 34 for separating paper, separation claw 35 for separating copy paper P from the surface of photoconductor drum 30, cleaning device 36 for cleaning toner remaining on the surface of photoconductor drum 30, and photoconductor drum A static eliminator 37 for neutralizing the potential remaining on the surface of the surface 30 is arranged in order.

At the bottom of the copying machine 2 located below the photosensitive drum 30, a multi-stage paper feeding device as a paper feeding means is detachably mounted in a plurality of upper and lower stages from the front side of the copying machine 2.
40 (hereinafter referred to as PFP) is arranged integrally with the copying apparatus 2.

The PFP 40 includes an upper cassette 41, a middle cassette 42 and a lower cassette 43 for accommodating a plurality of types of copy sheets P of various sizes. Each of the cassettes 41, 42 and 43 is, for example, in the longitudinal direction. The A4 size copy sheet, the B4 size copy sheet and the A3 size copy sheet placed so as to be conveyed along are each formed to be able to store about 500 sheets.

Pickup rollers 44a, 44b and 44c are provided at predetermined positions of the upper cassette 41, the middle cassette 42 and the lower cassette 43 to take out the sheets P one by one from the respective cassettes 41, 42 and 43.

Each pickup roller 44a, 4
4b and 44c for each cassette 41, 42 and 4
A conveyance roller 45 for separating the sheets P one by one is provided at a position where the leading edge of the sheet P taken out from the sheet 3 is passed.
a, 45b and 45c, and separation rollers 46a, 46b and 46 disposed integrally with the respective transport rollers.
c is arranged. The separation rollers 46a, 46b and 46c are arranged such that their axes are parallel to the mutually combined transport rollers and are in contact with each other at a predetermined pressure, and rotate in a direction opposite to the rotation direction of the transport rollers. By doing so, only the uppermost one sheet of the paper P taken out from each cassette is delivered to the transport path described later.

To the right of the PFP 40 in the figure, there are 3 sheets of paper P of a size that is frequently used, for example, A4 size paper P.
A large-capacity feeder (hereinafter referred to as LCF) 47 that can store about 000 sheets is provided. LCF47
The paper P accommodated in the LDF 47 is
A pickup roller 48 is arranged to take out the sheets one by one. A separating mechanism 49 including a pair of upper and lower conveying rollers 49a and a separating roller 49b is arranged between the pickup roller 48 and the photosensitive drum 30. The separating mechanism 49 rotates the separating roller 49b in a direction opposite to the direction in which the conveying roller 49a is rotated, so that only the uppermost one sheet of the paper P taken out from the LDF 47 by the pickup roller 48 is conveyed as described later. Send to the road.

Above the LCF 47, each cassette 41,
Copy paper P independently of 42, 43 and LCF 47
A manual feed feeder 50 capable of feeding paper is formed. Between the manual feed feeder 50 and the photoconductor drum 30, a manual feed pickup roller 51 for taking in the paper P inserted in the manual feed feeder 50, a manual feed guide 52 for guiding the paper P taken in by the pickup roller 51,
Further, a conveyance roller 53 that conveys the sheet P guided toward the photosensitive drum 30 via the manual feed guide 52 is provided.

The respective cassettes 41, 42 and 43
In addition, between the LCF 47 and the photoconductor drum 30, the conveyance path 5 for guiding the paper P from the cassettes 41, 42 and 43 and the LCF 47 toward the photoconductor drum 30.
4 are formed. The conveyance path 54 further extends to the outside of the copying apparatus 2 via a transfer area defined between the photosensitive drum 30 and the transfer / separation charger 33. Further, in the transport path 54, the paper P fed from any of the cassettes, the LCF, or the manual feed guide is used.
A plurality of transport rollers 55 for transporting the sheet toward the photoconductor drum 30 are provided.

In the vicinity of the photosensitive drum 30 on the conveying path 54 and on the upstream side, the copy sheet P guided along the conveying path 54.
Of the toner image on the photoconductor drum 30 and the tip of the copy paper P are aligned, and the copy paper P is transferred to the transfer area at the same speed as the moving speed of the outer peripheral surface of the photoconductor drum 30. An aligning roller 56 for feeding paper is arranged. Further, in front of the aligning roller 56, that is, on the side of the transport roller 55, the aligning roller 56
An aligning sensor 56a is provided for detecting the arrival of the copy sheet P to the sheet.

A conveyor belt 57 that conveys the paper P is incorporated in the direction in which the paper P that has passed through the transfer area advances. At the position where the paper P is conveyed by the conveyor belt 57 and the heat is less likely to be applied to the photoconductor drum 30, a pair of heat rollers whose roller surfaces are in pressure contact with each other is included and the toner image is transferred to the paper. A fixing device 58 for fixing the toner image on the paper P by heating the toner image and melting the toner image to press the toner image and the paper P is provided.

On the side wall of the copying apparatus 2 facing the fixing device 58, the paper P having the toner image fixed by the fixing device 58 is provided.
A discharge tray 59 for discharging is disposed. Between the fixing device 58 and the discharge tray 59, a discharge switching unit 60 for guiding the copy sheet P on which the toner image is fixed by the fixing device 58 to a sheet reversing unit or a discharge tray 59 described later is disposed. I have.

The discharge switching unit 60 is arranged between the first and second discharge rollers 61 and 62 for propelling the sheet P that has passed through the fixing device 58, and between the first and second discharge rollers 61 and 62. A distribution gate 63 is provided for selectively distributing the copy paper P, which has passed through the fixing device 58, to either the discharge tray 59 or a paper reversing unit described later.

The reversing mechanism 64 includes a temporary stacking section 65 for temporarily stacking the copy sheets P that have already passed through the transfer area and the fixing device 58, and the copy sheets P having passed through the fixing device 58.
A reversing path 66 for inverting the front and back to a temporary stacking unit 65, a pickup roller 67 for taking out the copy sheets P stacked in the temporary stacking unit one by one, and an aligning roller for re-aligning the sheets P stored in the temporary stacking unit 65. A reversing conveyance path 68 for guiding the sheet P and a sheet feeding roller 69 for feeding the sheet P guided to the reversing conveyance path 68 toward the aligning roller 56 are provided.

The ADF 8 has a cover 71 and the cover 7
The rear edge of the copying machine 1 is attached to the rear edge of the upper surface of the copying apparatus 2 via a hinge device (not shown).
By rotating and displacing the entire DF 8, as described above, it is formed so as to be openable and closable with respect to the document table 11 of the image reading section 4.

A document feeding table 72 for holding a plurality of documents D is provided on the upper surface of the cover 71 slightly to the left. The documents D set on the document feed table 72 are sequentially taken out one by one on the left side of the document feed table 72 in the figure, that is, one end side of the ADF 8, and the document table 11 of the image reading unit 4 is read from the left end side in the figure. A pickup roller 73 for supplying to one end side of is arranged.

An empty sensor 73 as a document detecting sensor for detecting whether or not the document D is set on the document feeding table 72 is arranged at a predetermined position of the document feeding table 72. It should be noted that the document feeding table 72 has a document position detecting sensor 1 for detecting the position where the document D is set on the document table 11.
A document width detection sensor (not shown) that functions in the same manner as 7 may be arranged.

In the original pick-up direction of the pickup roller 73, the paper feed roller 74 for sending the original D taken out by the pickup roller 73 toward the original table 11 and the leading end of the original D fed by the paper feed roller 74 are arranged. An aligning roller 75 for aligning is arranged. The document D is placed between the aligning roller 75 and the paper feeding roller 74.
An aligning sensor 75a for detecting the arrival of the aligning roller 75 on the aligning roller 75 is arranged.

Inside the cover 71, at a position facing the platen 11 of the image reading section 4 in a state where the ADF 8 is closed, a size that covers almost the entire platen 11 is given, and a pickup roller is provided. A conveyance belt 76 is arranged to convey the document D conveyed from the document feed table 72 via the document feed roller 74 and the aligning roller 73 to a predetermined position on the document table 11. The conveyor belt 76 is stretched around belt rollers 77 arranged in a pair in the left and right in the figure, and is rotated by a belt drive mechanism (not shown) toward both the right side in the figure and the left side in the figure.

A conveyor belt 76 is provided on the right side of the ADF 8.
Thus, the reversing roller 78 that sends the document D moved from the left side to the right side in the drawing toward the outside of the cover 71, the pinch roller 79 that presses the document D against the reversing roller 78, and the reversing roller 78 and the pinch roller 79 convey the document D. Document D
Flapper 8 which switches between returning to the transport belt 76 again or discharging to a predetermined discharge position, that is, the cover 71.
0, when the flapper 80 is switched to the discharge side, a discharge roller 81 for discharging the document D conveyed by the reversing roller 78, and a jam sensor 82 for detecting a jam of the document near the reversing roller 78 And so on.

FIG. 1 is a block diagram schematically showing a control mechanism of the electrophotographic digital copying apparatus 2 shown in FIG. The electrophotographic digital copying apparatus 2 includes a control panel unit 110, a scanner unit 120, and a printer unit 13.
0, a memory editing unit 140, a system unit 150, and a main control unit 160.

The control panel section 110 includes a control panel (not shown) and a control panel CPU 11.
1. Read-only memory (hereinafter referred to as ROM) 112 and random access memory (hereinafter referred to as RAM) connected to the control panel CPU 111
113, including input detection by various switches and touch panel, display on touch panel, and LE
It is used for exchanging control data with the user by turning on and off D.

The control panel CPU 111 uses the RO
Based on the data stored in the M112 and the RAM 113, detection of input by various switches and a touch panel (not shown) of the control panel, display on the touch panel, and turning on and off of the LED are controlled.

The scanner unit 120 includes the scanner CPU 12
1 and a ROM 122 connected to the scanner CPU 121
And RAM 123, ROM 122 and RAM
By the control of the scanner CPU 121 based on the control data stored in 123, the CCD of the image reading unit 4
A mechanism for operating the image sensor 24 to capture the image of the document D as light and dark information of light and energizing a DC motor or the like (not shown) for moving the first carriage 16 and the second carriage 20 at a predetermined speed. A predetermined drive signal is output to the control unit 124.

Further, the scanner section 120 passes through the A / D conversion circuit 125 and the A / D conversion circuit 125 which convert the analog image data output from the CCD image sensor 24 into a digital signal by a known A / D conversion. The shading correction circuit 126 that removes the influence of the individual error of the output of the CCD image sensor 24 and the nonuniformity of the light amount from the illumination lamp 13 from the image signal converted into the digital signal, and the CCD image sensor 24 read the shading correction circuit 126. It has a line memory 127 for supplying the image information of the document D to the memory editing unit 140 connected at the subsequent stage at a predetermined timing, and has the ROM 122 and RA.
Under the control of the scanner CPU 121 based on the data of M123, the image information of the document D read by the CCD image sensor 24 is converted into an electric signal, which is then binarized at a predetermined threshold level and connected to the memory editing unit 140 at the subsequent stage. To the page memory described later.

The scanner CPU 121 has an ADF
8 is also connected. The ADF 8 is the scanner CPU 1 based on the control by the main control unit 160 described later.
The document D is fed under the control of 21. Also, the scanner C
When editing data is input to the PU 121 from a coordinate input device (not shown), predetermined control data is output to the page memory of the memory editing unit 140, which will be described later, and image data used for image formation is held. An editor 128 for controlling the size of the memory area is also connected.

The printer unit 130 includes the printer CPU 13
1 and a ROM 132 connected to the printer CPU 131
An image is formed on the paper P based on the image information read by the image reading unit 4, that is, the scanner unit 120 and the image data supplied from an external device described later.

In the printer CPU 131, the photosensitive drum 30, the developing roller 33a of the developing device 33, the aligning roller, the conveying belt, the fixing device, the reversing mechanism, and the cassettes 41, 42 and 43 of the multi-stage paper feeding device 40, and A motor drive circuit 134 that drives a motor (not shown) that rotates such as a pickup roller and a conveyance roller and a separation roller arranged in each LDF 47, a document position detection sensor 17 that detects the position of the document D set on the document table 11, and A paper empty switch (not shown) arranged in each of the cassettes 41, 42 and 43 and the LDF 47, the conveyance path 54 and the reversing mechanism 6
4, a lever switch (not shown) that detects jamming of the paper P, an input circuit 135 that is used for inputting signals output from switches and sensors such as the aligning sensor 56a, and For example, a mechanism control unit 136 for urging a sorting gate 63 of the discharge switching unit 60 or a solenoid (not shown) included in the cleaning device 35 is connected.

The printer CPU 131 also includes a temperature control circuit 137 for controlling the temperature of the fixing device 58, a voltage supply circuit 138 for applying a predetermined voltage to a charging charger, a developing device, a transfer / peel charger, and the like, and a laser exposure device. A laser drive circuit 139 for intensity-modulating the light intensity of a laser beam emitted from a laser diode (not shown) 32 corresponding to image data supplied from a page memory, which will be described later, is connected to the ROM 132 and the RAM.
An image is formed on the paper P under the control of the printer CPU 131 based on the data 133.

The memory editing unit 140 is a memory control CPU.
141, a main CPU of the main control unit 160 described later, and a system C of the system unit 150 described later.
Image data supplied from the scanner unit 120 or an external device according to an instruction from both the PU and the printer unit 1
After being converted into bitmap data used for intensity modulation of the laser beam emitted from the laser diode of the laser exposure device 32 of 30, the page memory shown in the subsequent stage is temporarily stored.

In the memory control CPU 141, image data supplied from an external device via the system unit 150 and predetermined by an image processing unit described later in the main control unit 160 after being read by the scanner unit 120. An image editing unit 142 that edits the image data of the document D converted to the format, a compression / decompression unit 143 that compresses or decompresses the input image data, and an enlargement / reduction or rotation of the input image data. Reduction / rotation unit 14
4, a page memory 145 that stores image data processed through the image editing unit 142, the compression / expansion unit 143, and the enlargement / reduction / rotation unit 144 page by page, an address control unit 146 that manages memory addresses, and a memory A memory management control unit 147 for managing the data of the above, and an interrupt control unit 148 for giving instructions for processing such as compression / expansion and enlargement / reduction / rotation to the image data taken in by the image editing unit 142. Are connected.

The system section 150 includes a system CPU 151 for controlling the capture of image data supplied from other than the scanner section 120, and a facsimile apparatus 152 as an external apparatus connected to the system CPU 151, a hard disk apparatus 153, a computer not shown and A LAN 154 to which a word processor or the like is connected, and a printer controller 155 for converting image data supplied via the facsimile 152, the hard disk device 153, and the LAN 154 from code data into image data in a format processable by the copying apparatus 2, respectively. By controlling, the image editing unit 142 of the memory editing unit 140 is made to input the image data.

The main control section 160 operates in the copying apparatus 2, that is, the CPUs 121 and 13 of the control panel section 110, the scanner section 120, the printer section 130, the memory editing section 140 and the system section 150, respectively.
Main CPU 161 controlling 1, 141 and 151
Having a control panel section 110 and a scanner section 12
0, the printer unit 130, the memory editing unit 140, and the system unit 150 are controlled to pass signals.

The main CPU 161 has a ROM 162 in which initial data and the like for operating the copying apparatus 2 are stored, and the control panel section 110, the scanner section 120, and the printer section 130 under the control of the CPUs 121, 131, 141 and 151. , Memory editing unit 14
0 and the RAM 163 holding various data input from the system unit 150, respectively.

The main CPU 161 also holds a printer font R that holds a printer font used to store the code data input via the system section 150 in the page memory 145 of the memory editing section 140.
The OM 164 displays an image corresponding to the code data input via the system unit 150 on an editing display device (not shown), and displays a predetermined image on a liquid crystal display / input panel of a control panel (not shown). Display font ROM 165 for holding display fonts for specifying, destination of image data read by the scanner unit 120, and printer unit 130
An image used for switching image data supplied to the scanner unit 120 and transferred between the line memory 127 of the scanner unit 120 and the page memory 145 of the memory editing unit 140 and between the page memory 145 and the laser exposure device 32. A data switching / buffer memory 166 that functions as a buffer memory for data, and an image processing unit 167 that masks or trims input image data are connected.

Next, the copying operation of the image of the original by the copying apparatus shown in FIGS. 1 and 2 will be described. When the main switch (not shown) is turned on, the copying apparatus 2 is warmed up and initialized according to the control program stored in the ROM 162. Further, the scanner unit 120 under the control of the main CPU 161.
AD (not shown) according to an instruction from the scanner CPU 121 of
The ADF 8 is also initialized according to the control program stored in the FROM.

When a document key to be copied is set on the document tray 72 of the ADF 8 and a print key (not shown) of a control panel (not shown) is turned on, an empty sensor (not shown) of the ADF 8 is turned on by an ADF CPU (not shown). Checked.

When the empty sensor detects that the document D is set on the document tray 72, the pickup roller 73 is driven by the supply of a drive current from a motor drive circuit (not shown) to a paper feed motor (not shown). Then, the lowermost original of the original D set on the original tray 72 is guided to the paper feed roller 74.

The document D guided by the paper feed roller 74 is further conveyed toward the aligning roller 75.
Subsequently, when the leading end of the document D passes through the aligning sensor 75a, a clutch (not shown) is turned on via an ADF mechanism control unit (not shown), and the aligning roller 75 is stopped. As a result, the document D taken out from the document tray 72 is temporarily stopped by the pickup roller 73, and the inclination of the document D with respect to the document transport direction is corrected. Thereafter, after the belt roller 77 is rotated in the first direction, that is, the document feeding direction by the drive motor (not shown), and the transport belt 76 is rotated, the clutch (not shown) is turned off at a predetermined timing, and the aligning roller 75 The document D is fed to the transport belt 76.

Subsequently, the conveyor belt 76 is operated by the conveyor motor.
Is rotated for a predetermined time, the document D is conveyed onto the document table 11 of the copying apparatus 2. The conveyor belt 76 is stopped after a certain time has passed since the trailing edge of the document D has passed the aligning sensor 75a, that is, after a predetermined time depending on the interval between the aligning sensor 75a and the reference indicating device 12. A brake (not shown) prevents rotation due to inertia.

At the time when the leading edge of the document D is detected by the aligning sensor 75a, the scanner CPU 121 of the scanner unit 120 of the copying apparatus 2 is transferred from the ADF CPU (not shown).
Is notified that the document D has been conveyed to a predetermined position, and subsequently, the main CPU 161 is based on the size of the document D detected through the ADF 8 and the copy magnification set through a control panel (not shown). Thus, the cassette containing the paper P having the optimum size is selected.

Subsequently, according to the input copy magnification, C
Image data is read from the CD line sensor 24 into the line memory 127. The read start position of the image data is the ROM.
After being called from 162, it is stored in the RAM 163.

Next, the illumination lamp 1 of the first carriage 16
3 is turned on with a predetermined brightness, and the first carriage 16 is moved at a predetermined speed along the document D on the document table 11 by the rotation of a pulse motor (not shown).

Subsequently, the image information of the document D placed on the document table 11 is reflected light generated by being illuminated through the exposure lamp 13 and the reflection plate 14 as the first mirror 15 of the first carriage 16. And the second carriage 20
Are sequentially reflected by the second mirror 21 and the third mirror 22, and the CCD line sensor 24
Is imaged on the reading surface of.

The image information of the original D imaged on the CCD line sensor 24, that is, the reflected light from the original D is photoelectrically converted by the CCD line sensor 24 at a predetermined resolution, and then read to the reading start position stored in the RAM 163. The pixels of the corresponding CCD line sensor 24 are sequentially picked up from a pixel at a predetermined position (not shown), and the A / D conversion circuit 125 outputs 2 pixels.
The value is converted into a value, the threshold level is corrected via the shading correction circuit 126, and the corrected value is output to the line memory 127.

The image data input to the line memory 127 is transferred to the image processing unit 167 via the data switching / buffer memory 166 and subjected to predetermined correction and conversion such as character identification and contour correction. ,
It is output to the page memory 145. Page memory 145
The image data input to is converted into a laser drive signal (print signal) through a parallel-serial conversion circuit (not shown), and then supplied to the laser exposure device 32.

In parallel with the reading of the image information of the document D by the scanner section 120 (or at a predetermined timing),
The motor drive circuit 134 is controlled by the control of the main CPU 161.
The motor (not shown) is energized by the supply of the motor drive voltage from the photosensitive drum 30 to rotate the photosensitive drum 30 at a desired speed.

At the same time, a predetermined potential is applied from the charging device 31 to the surface of the photosensitive drum 30 by the control of the voltage supply circuit 138. As an example, the initial surface potential of the photosensitive drum 30 is set to about -650 volts.

Subsequently, by the laser exposure device 32,
Image data corresponding to the image of the original D, that is, page memory 145 is stored on the surface of the photoconductor drum 32, and in response to a print signal converted from bitmap data to serial data via a parallel-serial conversion circuit (not shown). The modulated laser beam is emitted. The emission timing of the laser beam emitted from the laser exposure device 32, that is, the writing start position is not shown based on the writing position stored in the RAM 163 corresponding to the size of the sheet P, as described above. Needless to say, a delay is added from the horizontal synchronization signal by a predetermined clock in the main scanning direction.

As a result, an electrostatic latent image corresponding to the print signal (image data) is formed on the outer peripheral surface of the photosensitive drum 30. The electrostatic latent image thus formed is developed by the voltage supply circuit 138 with toner supplied from the developing roller 33a of the developing device 33 to which a developing bias voltage of -450 volts is applied, for example. Then, the toner image is transferred to the paper P by the transfer output from the transfer / peeling charger 34 to which a predetermined transfer voltage is applied by the voltage supply circuit 138.

The toner image transferred to the paper P is transferred to the photosensitive drum 30 together with the paper P by the separation output from the transfer / separation charger 34 to which a predetermined separation voltage is applied by the voltage supply circuit 138 and the separation claw 35. It is peeled from the surface and conveyed to the fixing device 58 by the conveyor belt 57,
The sheet P is fixed on the sheet P via the fixing device 58.

The sheet P on which the toner image is fixed is transferred to the copying machine 2 via the first and second discharge rollers 61 and 62.
The paper is discharged to a paper discharge tray 59 arranged outside the printer.
The photoreceptor drum 30 having transferred the toner image onto the paper P is continuously rotated, the remaining toner is removed via the cleaning device 36, and then the charge is removed by the charge removing device 37, and subsequently used for the next image formation.

On the other hand, when the reading of the first document D, which is currently positioned on the document table 11, is completed, the main C
Under the instruction of the scan CPU 121 under the control of the PU 161, the ADF CPU (not shown) is requested to feed the next original D, that is, replace the original D. That is, the transport motor is rotated by the drive current from the motor drive circuit (not shown) to the transport motor (not shown), and the transport belt 76 is rotated.
Is rotated.

As a result, the first document currently set on the document table 11 is conveyed toward the reversing roller 78, and the flapper 80 and the paper discharge roller 81 cover the cover 7.
The document is discharged to a document receiving area formed at a predetermined position.

Subsequently, an empty sensor (not shown) checks whether or not the document D continues, and if the document D remains, the document feeding operation is repeated.
Similarly to the first document, the second document is set on the document table 11, and the image information of the second document is read.

In this way, the document tray 7 of the ADF 8 is
A series of image formation is repeated for all the documents D set to 2. By the way, as already explained,
Each of the optical members used in the image reading unit 4 has, for example, the thickness of the glass of the document table 11, the thickness of the first to third mirrors 15, 21 and 22, or the CCD image sensor 24 fixed thereto. It has various component tolerances such as the deviation of the light-receiving surface with respect to the position.

Even if the accuracy of each component is increased to such a degree that the component tolerance of each optical member can be neglected, for example, a mounting error between the mirror 15 and the first carriage 16, a second error, and a second error. 3 between the mirrors 21 and 22 and the second carriage 20, the distance between the document table 11 and the imaging lens 23 or the imaging lens 23 and C.
Due to the influence of error factors such as the distance between the light receiving surface of the CD image sensor 24 and the like, it is only necessary to assemble the respective optical members formed with a predetermined allowable value so that the image forming lens 23 of the image forming lens 23 is assembled for each copying apparatus 2. It is well known that the position or the position of the CCD image sensor 24 must be finely adjusted.

By the way, as shown in FIG. 3, the image reading unit 4 used in the copying apparatus 2 has a distance L1 between the document table 11 and the front principal point of the imaging lens 23 and the rear of the imaging lens 23. Since the distance L2 between the side principal point and the CCD image sensor 24 is a reduction optical system of about 10 times, either or both of the imaging lens 23 and the CCD image sensor 24 are moved to obtain a predetermined optical characteristic. Ensuring is a problem that requires a high degree of skill and a great deal of adjustment time. When the focal length of the image forming lens 23 is f and the image forming magnification is m, L1 = {(1 / m) +1} f + t t is a correction value considering the thickness of the document table 11. Shown. Similarly, the distance L2 is represented by L2 = (m + 1) f, where f is the focal length of the imaging lens 23 and m is the imaging magnification.

Therefore, for example, there has been proposed a method of adjusting the position of the CCD image sensor 24 by rotating the cam a, using a moving mechanism, that is, a cam mechanism as shown in FIG.

However, the CCD image sensor 24
A slight change in the position of the
Between the imaging lens 23 and the platen 11 is approximately 10 times
Since it is increased to about (the reciprocal of the magnification of the optical system), it is known that the movable amount of the CCD image sensor 24 is actually limited to a limited narrow range. In addition, the CCD image sensor 24
Since the light receiving surface of the CCD image sensor 24 and the optical axis of the CCD image sensor 24 are likely to tilt when is moved, a high degree of skill is required for the adjustment work.

An example in which the imaging lens 23 and the CCD image sensor 24 are treated as substantially one unit is proposed, like the CCD unit 26 shown in FIG. 2, but in this case as well, Platen 11 and unit 26
It is necessary to adjust the magnification and the focal length between and. That is, it is known that the entire CCD unit 26 must be moved in the adjustment work.

FIG. 5 is a perspective view showing in detail the CCD unit 26 incorporated in the image reading section 4 of the digital copying apparatus 2 shown in FIGS. 1 and 2. As shown in FIG. 5, the CCD unit 26 includes the imaging lenses 23 and C.
It has an optical base 26a that holds each of the CD image sensors 24 at predetermined intervals.

On the optical base 26a, a lens holding portion 26b to which the imaging lens 23 is fixed, a CCD holding portion 26c to which the CCD image sensor 24 is fixed, and between the lens holding portion 26b and the CCD holding portion 26c. It has an optical path length adjusting plate holding portion 27 which holds the optical path length adjusting plate 28 which is formed and has a predetermined thickness which will be described in detail with reference to FIG. The lens holding portion 26b, the CCD holding portion 26c, and the optical path length adjusting plate holding portion 27 are integrally formed with the optical base 26a. Therefore, since each of the CCD image sensor 24 and the imaging lens 23 is fixed to the optical base 26a, the angle formed between the light receiving surface of the CCD image sensor 24 and the optical axis of the imaging lens 23 is different for each CCD unit 26. It is prevented from changing.
From this, the optical path length is adjusted as will be described later with reference to FIG. 8, and the light receiving surface of the CCD image sensor 24 is simply made to coincide with the magnification and focus, that is, the focal position of the imaging lens 23. Assembly and adjustment is completed.

The optical base 26a also holds a light transmission member (not shown) similar to the optical path length adjusting plate 28 in order to correct the optical path length between the imaging lens 23 and the third mirror 22. The light transmitting member holding portion 26d is integrally formed closer to the third mirror 22 than the lens holding portion 26b, that is, closer to the document table 11 than the incident surface of the imaging lens 23. The CCD image sensor 24 and the imaging lens 23 are fixed to a fixing member (not shown) having a predetermined shape, and then C
It may be mounted on the CD holding portion 26c and the lens holding portion 26b.

The optical path length adjusting plate 28 is a parallel plate of glass or plastic having a predetermined refractive index and has a refractive index of n and a thickness of 1 millimeter (hereinafter referred to as [mm]) to 4 [mm]. Stipulated in.

The optical path length adjusting plate 28 is actually a plurality of plates 28 whose thickness is changed by 0.2 [mm].
Then, according to the correction method described later using FIG. 8,
Only one is selected. Although it is possible to form the optical path length adjusting plate 28 to a thickness of 1 [mm] or less, since the mechanical strength is insufficient, the lens holding portion 26b and the CCD holding portion 26c of the CCD unit 26 are not formed. The distance between them is set to be slightly longer than the focal length of the imaging lens 23, and the optical path length adjusting plate 28 is inserted so that the light passing through the imaging lens 23 is actually imaged. A method of matching the light receiving surfaces of the CCD image sensor 24 is used.

6 and 7 are schematic views showing an example of the optical path length adjusting plate holding portion 27 of the CCD unit 26 shown in FIG. Referring to FIG. 6, the optical path length adjusting plate holder 27
Are formed so as to be able to hold a plurality of types of optical path length adjusting plates 28 ...

The optical path length adjusting plate holder 27 is selected
Reference surface 27 holding one surface of one optical path length adjusting plate 28
a, a first rib 27b formed at a first distance T1 from the reference surface 27a, and a second distance T from the reference surface 27a.
The second rib 27c formed with the second rib 27c, the third rib 27d formed with the third distance T3 from the reference surface 27a, and the fourth rib formed with the fourth distance T4 with respect to the reference surface 27a.
It has a rib 27e.

Each of the ribs 27b to 27e has a specific length D1 to D4 defined corresponding to the first to fourth intervals T1 to T4. The distance between the reference surface 27a and the surface of the first rib 27b facing the reference surface 27a, that is, the first interval T1 is, for example, 2 [mm]. The second distance T2, the third distance T3, and the fourth distance T4 are 3 [mm] and 4 [m], respectively.
m] and 5 [mm].

On the reference surface 27a, for example, a sliding member (not shown) is formed by surface processing which can be integrally formed at the time of molding the optical base 26a or powder coating after molding. The surface of the first to fourth ribs 27b to 27e facing the reference surface 27a has, for example, 1.5 [m]
An elastic body having a thickness of m], for example, felt or sponge 27f is attached.

According to the optical path length adjusting plate holding portion 27 shown in FIG. 6, a plurality of types of optical path length adjusting plates 28 ... The first to fourth ribs 27b to 27c, which are provided with an approximate spacing.
The single selected optical path length adjusting plate 28 can be easily held only by inserting it between the reference surface 27a and the reference surface 27a. The optical path length adjusting plates 28 are fixed by being pressed toward the reference surface 27a by the elastic body 27f.

Further, the optical path length adjusting plates 28 ...
In order to be fixed to the optical path length adjusting plate holding portion 27 by the fourth ribs 27b to 27e, predetermined lengths Y1 to Y4 defined based on the thickness of the adjusting plates 28 are provided. . Here, the length Y of the optical path length adjusting plate 28.
1 to Y4 are the first ribs 27 when the thickness of the adjusting plates 28 ... Is less than 1.2 [mm], for example.
It is defined as Y1 which can be fixed by b. Hereinafter, the thickness of each of the adjusting plates 28, ... Is the second rib 27 when the thickness of each of the adjusting plates 28 is, for example, 1.2 to 2 [mm].
When the thickness of the adjusting plates 28 ... Is fixed to Y2 which can be fixed by c, for example, 2.2 to 3 [mm], the adjusting plates 28 can be fixed to Y3 which can be fixed by the third rib 27d. ...
When the thickness is, for example, 3.2 to 4 [mm], it is defined as Y4 which can be fixed by the fourth rib 27e.

FIG. 7 is a schematic view showing a fixing structure different from the optical path length adjusting plate holding portion 27 shown in FIG. As shown in FIG. 7, the optical path length adjusting plate holding portion 227 has a pair of stays 227a positioned at both ends of a plurality of types of optical path length adjusting plates 28 ... ing. A sliding contact (not shown) is formed on the surface of the stay 227a that comes into contact with the optical path length adjusting plates 28 ... By knurling or powder coating, for example.

An adjusting plate pressing spring 227b made of, for example, stainless steel for spring or phosphor bronze is attached to each stay 227a.
According to the optical path length adjusting plate holding portion 227 shown in FIG. 7, one optical path length adjusting plate selected with a single configuration is not limited by the thickness of the optical path length adjusting plates 28. 28 can be easily held. The optical path length adjusting plates 28 are fixed by being pressed toward the stay 227a by the adjusting plate pressing spring 227b.

FIG. 8 shows the CCD unit 26 shown in FIG.
At the same time, the optical path length adjusting plate 28 ... Causes the light passing through the imaging lens 23 to be imaged on the light receiving surface of the CCD image sensor 24 at a predetermined magnification, and the position of the light receiving surface of the CCD image sensor 24 is adjusted. FIG. 6 is an optical path diagram showing a method for optically matching the focal position of the imaging lens 23.

As shown in FIG. 8, one optical path length adjusting plate 2
In the CCD unit 26 including 8, the document surface (the surface where the document D set on the document table 11 and the document table 11 contact)
When the focal length of the image forming lens 23 is f and the image forming magnification is m, the distance L1 between the image forming lens 23 and the front principal point of the image forming lens 23 is
Similarly to the case shown in FIG. 3, L1 = {(1 / m) +1} f + t t is represented by a correction value considering the thickness of the document table 11. On the other hand, the distance L2 between the rear principal point of the imaging lens 23 and the CCD image sensor 24 is f as the focal length of the imaging lens 23, m as the magnification, and d as the thickness of the optical path length adjusting plate 28. Then, L2 = (m + 1) f + {(n-1) / n} d.

Hereinafter, the refractive index of the glass used for the document table 11 is 1.5, the thickness of the glass is 4 [mm], the magnification m is 1/10, and the focal length f of the imaging lens 23 is 46 [. mm]
Then, the distance L1 is L1 = 507.33 [mm]. On the other hand, the distance L2 is equal to the optical path length adjusting plate 28.
When the refractive index n of is set to 1.5, it is expressed by L2 = 50.6 + 0.33d [mm]. Therefore, the thickness d of the optical path length adjusting plate 28 is set to 3
If it is [mm], the distance L2 is 51.6 [mm].

Hereinafter, when the image reading section 4 of the copying apparatus 2 is assembled, the position of the CCD unit 26 is set to the image forming lens 2.
3 and the document table 11 are arranged along an optical axis (not shown), the output signal of the CCD image sensor 24 is monitored, and the CCD unit 26 is placed at a position where the output signal waveform of the CCD image sensor 24 matches the reference waveform. The image reading unit 4 is configured by fixing the.

Here, due to a mounting error between the first mirror 15 and the first carriage 16, a mounting error between any of the second and third mirrors 21 and 22, or a mounting error between both of them and the second carriage 20, etc. Due to this, when it becomes necessary to finely adjust the distance between the light receiving surface of the CCD image sensor 24 and the rear principal point of the imaging lens 23, the thickness of the optical path length adjusting plate 28 is changed, that is, the optical path is already changed. By simply replacing the optical path length adjusting plate 28 inserted in the length adjusting plate holding portion 27 with the optical path length adjusting plate 28 having a different thickness, C
The position of the light receiving surface of the CD image sensor 24 can be optically matched with the focal position of the imaging lens 23. The distance L2 is set such that the refractive index n of the optical path length adjusting plate 28 is 1.5.
When the thickness changes by 1 [mm], 0.
It is changed by 33 [mm]. Further, the distance L2 is obtained by setting the thickness of the optical path length adjusting plate 28 to 3 [mm] and the refractive index n is
Each time it changes by 0.05, it is changed by 0.1 [mm]. In order to change the refractive index n, the material of the optical path length adjusting plate 28 may be replaced with plastic.

In addition, for example, because the thickness of any one of the mirrors is different, the C of the optical path length adjusting plate 28 alone is used.
The position of the light receiving surface of the CD image sensor 24 is set to the imaging lens 2
When it is not possible to optically match the focal position of No. 3, that is, when the distance L1 is greatly changed, the light transmitting member holding portion 26d functions similarly to the optical path length adjusting plate 28 (substantially, the optical path. By inserting a light transmitting member (which is the same as the length adjusting plate 28), the distance L1 and the distance L2 can be optimally set.

FIG. 9 is a schematic diagram showing the output signal waveform and the reference waveform of the CCD image sensor 24 used to define the optimum optical path length adjusting plate 28 in the optical path length adjusting step shown in FIG. is there.

Each pixel of the CCD image sensor 24 has a reading resolution of 400 dpi eye (dot per inch, hereinafter referred to as [dpi]) for reading the image of the original D set on the original table 11. Assuming that the magnification m is 1/10, it means that they are arranged at 4000 [dpi]. In addition, the CCD image sensor 24
Normally, the output signal is output in 2 channels or 4 channels.

Therefore, for example, a test document of 8 line pairs / mm (hereinafter referred to as [book / mm]) is set on the document table 11, and the reflected light obtained by illuminating with the illumination lamp 13 is sampled at the sampling frequency. 10 MHz
When the image of the test original is read as (hereinafter, referred to as [MHz]), if the CCD image sensor 24 has two channels, the output signals of the odd pixel and the even pixel of the CCD image sensor 24 are different from each other. It is output to the channels in order.

The output signal from the CCD image sensor 24 is processed by the image processing section 167 via the data switching / buffer memory 166, and is displayed on the LCD display section of the touch panel (not shown) of the control panel (not shown) as shown in FIG. It is displayed in the form of a graph as shown in FIG.
It should be noted that the CCD image sensor 2 is combined with a signal extraction line (not shown) for the adjustment process and a measuring device such as an oscilloscope or an FFT analyzer (not shown).
The output signals of each of the four channels may be directly monitored.

When the output signals corresponding to the images of the test document output to the respective channels are combined, the distance L2 between the rear principal point of the imaging lens 23 and the CCD image sensor 24, the document table 11 and the image formation. When each of the distances L1 from the front principal point of the lens 23 matches the predetermined distance, a standard output signal as shown in FIG. 9A is obtained.

Assuming that the amplitude of the standard output signal shown in FIG. 9A is "a" and the pitch is "b", for example, as shown in FIG.
As shown in (e), when the pitch b is narrow, it can be detected that the magnification is shifted in the enlargement direction. In addition, FIG.
As shown in (f), when the pitch b is wide, it can be detected that the magnification is shifted in the reduction direction. Note that FIG.
The difference in magnification shown in (e) and FIG. 9 (f) is caused by the optical path to be inserted into the light transmitting member holding portion 26d of the CCD unit 26, the glass or plastic having a predetermined thickness, that is, the optical path length adjusting plate holding portion 27. By adjusting the distance L1 by inserting a light transmitting member which is substantially the same as the length adjusting plate 28, the adjustment can be easily performed.

Further, for example, FIG. 9 (b) and FIG.
As shown in (c), when the amplitude a is small, the CCD
It can be detected that the position of the light receiving surface of the image sensor 24 does not coincide with the focal position of the imaging lens 23, that is, the defocused state. The CCD image sensor 2
The output of No. 4 becomes maximum at the time of focusing, that is, when the focal position of the imaging lens 23 and the light receiving surface of the CCD image sensor 24 coincide with each other. Therefore, the amplitude a does not exceed the standard output signal. Therefore, FIG. 9 (b) and FIG. 9 (c)
In the defocused state shown in FIG. 6, that is, the shift between the focus position of the imaging lens 23 and the light receiving surface of the CCD image sensor 24
By inserting the optical path length adjusting plates 28 into the optical path length adjusting plate holding portion 27 of the CD unit 26 and changing the distance L2,
Easy to adjust. In this case, the adjustment time required to select the optical path length adjusting plate 28 can be reduced by obtaining the correlation between the magnitude of the amplitude a and the thickness of each optical path length adjusting plate 28.

FIG. 9D shows the CCD image sensor 24.
Shows the state where the light receiving surface of is fixed at an angle other than 90 ° with respect to the optical axis, that is, one focus. In this case, C
Since the positions where the CCD image sensor 24 and the imaging lens 23 are fixed in advance are deviated by the lens holding portion 26b and the CCD holding portion 26c of the CD unit 26, the optical path length adjusting plate 28 ... Or the light transmitting member. Cannot be adjusted by using. Therefore, it is necessary to change the mounting position of the imaging lens 23 or the CCD image sensor 24. Since the lens holding portion 26b and the CCD holding portion 26c are integrally molded at a predetermined position on the optical base 26a that is optimized so as not to cause one-sided focusing, one-sided focusing does not actually occur. Absent.

In this way, the position of the light receiving surface of the CCD image sensor 24 can be adjusted without requiring a high degree of skill by only preparing and replacing a plurality of optical path length adjusting plates 28 having different refractive indexes and thicknesses. Can be optically matched to the focal position provided by the imaging lens 23.

In FIG. 8, the adjustment method of inserting the optical path length adjusting plate 28 having a predetermined thickness between the rear principal point of the imaging lens 23 and the CCD image sensor 24 has been described. By setting a light-transmitting member having a predetermined thickness in the light-transmitting member holding portion 26d of 26a, the adjustment range in which the distances L1 and L2 can be adjusted can be expanded. Can be expanded. Therefore, the component cost is reduced.

In this case, the distance L1 between the original surface described with reference to FIG. 6 and the principal point on the front side of the imaging lens 23 is f, the magnification is m, the optical path length adjusting plate is f. 28
, Where L1 = {(1 / m) +1} f + t + {(n-1) / n} dt is given by a correction value considering the thickness of the document table 11.

[0121]

As described above, the image reading device of the image forming apparatus according to the present invention is arranged between the image forming means and the image reading means, and the position and the image where the light is formed by the image forming means. It has an optical path length matching means for optically matching the position of the light detection surface of the reading means.

The optical path length matching means has a predetermined thickness and refractive index, is arranged at least between the image reading means and the image forming means, and has a focusing property given to the reflected light from the original by the image forming means. Based on this, the position of the image reading means is optically corrected with respect to the position where the reflected light from the original is focused.

The optical path length matching means has a predetermined thickness and refractive index, and is arranged between the image reading means and the image forming means and between the image forming means and the document supporting means or both. The position of the image reading means is optically corrected with respect to the position where the reflected light from the original is focused based on the focusing property given to the reflected light from the original by the image forming means.

Further, the optical path length matching means is disposed between the image forming means and the image reading means, the distance between the rear principal point of the image forming means and the image reading means is L2, and the focal point of the image forming means. When the distance is f and the magnification is m, the position where the image is formed by the image forming unit and the position of the light detection surface of the image reading unit are L2 =
Thickness d satisfying (m + 1) f + {(n-1) / n} d
And optically aligns the position where the light is imaged by the image forming means and the position of the light detection surface of the image reading means.

Therefore, the position of the light detection surface of the image reading means can be optically matched with the focus position provided by the image forming means in a short time without requiring a high degree of skill. This reduces the assembly cost of the device. Further, the adjustment range in which the distance between the document supporting means and the front principal point of the image forming means and the distance between the rear principal point of the image forming means and the light detection surface of the image reading means can be adjusted is expanded. Therefore, since the tolerance of the component tolerance of each optical member can be relaxed, the component cost can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing an image forming apparatus incorporating an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of the image forming apparatus shown in FIG.

FIG. 3 is a schematic diagram showing a relationship between a distance between a document surface of the image forming apparatus shown in FIG. 2 and an imaging lens and a distance between the imaging lens and a light receiving surface of a CCD image sensor.

FIG. 4 is a schematic view showing a method for correcting the mounting position of a CCD image sensor which has been conventionally used.

5 is a CCD unit capable of optimizing the relationship between the distance between the document surface and the imaging lens and the distance between the imaging lens and the light receiving surface of the CCD image sensor used in the image forming apparatus shown in FIG. FIG.

6 is a schematic diagram showing an example of an optical path length adjusting mechanism that optically corrects a distance between an imaging lens applied to the CCD unit shown in FIG. 5 and a light receiving surface of a CCD image sensor.

7 is a schematic view showing another example of the optical path length adjusting mechanism shown in FIG.

8 is a schematic diagram showing a relationship between a distance between a document surface of the image forming apparatus using the CCD unit shown in FIG. 5 and an imaging lens and a distance between the imaging lens and a light receiving surface of the CCD image sensor. .

9 is a schematic diagram showing a waveform of an output signal of a CCD image sensor used to select an optical path length adjusting plate used in the CCD unit shown in FIG.

[Explanation of symbols]

2 ... Digital copying device, 4 ... Image reading unit, 6 ... Image forming unit, 11 ... Original plate, 13 ... Exposure lamp, 14 ... Auxiliary reflector, 15 ... First mirror, 16 ... First carriage, 20
... second carriage, 21 ... second mirror, 22 ... third mirror, 23 ... imaging lens, 24 ... CCD image sensor,
26 ... CCD unit, 30 ... Photosensitive drum, 31 ... Charging charger, 32 ... Laser exposure device, 33 ... Developing device, 34 ... Transfer / peel charger, 35 ... Peel claw, 36
... cleaning device, 37 ... static eliminator, 40 ... multi-stage paper feeding device, 41 ... upper cassette, 42 ... middle cassette, 43
… Lower cassette, 47… LCF (Large capacity feeder), 5
0 ... Manual feeder, 52 ... Manual guide, 53 ... Conveying roller, 54 ... Conveying path, 55 ... Conveying roller, 56 ... Aligning roller, 56a ... Aligning sensor, 57 ...
Conveyor belt, 58 ... Fixing device, 59 ... Discharge tray, 11
0 ... Control panel section, 111 ... Control panel CPU, 112 ... ROM, 113 ... RAM, 120 ...
Scanner unit, 121 ... Scanner CPU, 122 ... RO
M, 123 ... RAM, 124 ... Mechanism control unit, 125 ... A
/ D conversion circuit, 126 ... Shading correction circuit, 12
7 ... Line memory, 128 ... Editor, 130 ... Printer section, 131 ... Printer CPU, 132 ... ROM, 13
3 ... RAM, 134 ... Motor drive circuit, 135 ... Input circuit, 136 ... Mechanism control section, 137 ... Temperature control circuit, 13
8 ... Voltage supply circuit, 139 ... Laser drive circuit, 140 ...
Memory editing unit 141 memory control CPU 142 image editing unit 143 compression / expansion unit 144 enlargement / reduction / rotation unit 145 page memory 146 address control unit 147 memory management control unit 148 ... Interrupt control section, 160 ... Main control section, 161 ... Main C
PU, 162 ... ROM, 163 ... RAM, 164 ... Printer font ROM, 165 ... Display font R
OM, 166 ... Data switching / buffer memory, 16
7 ... Image processing unit.

Claims (9)

[Claims] 1. An image forming means for forming image information of an original document supported by the original document supporting means on a predetermined position as light and darkness of light, and an image of the original image formed on the predetermined position by the image forming means. An image reading unit for converting information into an electric signal corresponding to light and shade of light, a position arranged between the image forming unit and the image reading unit, and a position where light is formed by the image forming unit and the image reading unit. And an optical path length matching means for optically matching the position of the light detection surface of the means. 2. An illuminating device for illuminating an original document supported by the original document supporting device, and an image reading device for photoelectrically converting reflected light from the original document illuminated by the illuminating device and outputting an image signal corresponding to the image of the original document. Means, an image forming means for forming an image of the reflected light from the document illuminated by the illuminating means on the image reading means, having a predetermined thickness and refractive index, and at least the image reading means and the image forming means. And a position of the image reading unit is optically arranged with respect to a position where the reflected light from the original is focused based on the focusing property given to the reflected light from the original by the image forming unit. And an optical path length matching means for correcting the image. 3. An illuminating device for illuminating an original document supported by the original document supporting device, and an image reading device for photoelectrically converting reflected light from the original document illuminated by the illuminating device to output an image signal corresponding to the image of the original document. Means, an image forming means for forming an image of reflected light from the document illuminated by the illuminating means on the image reading means, the image reading means and the image forming means having a predetermined thickness and refractive index. And the image forming unit and the document supporting unit, or both, and the light reflected from the document is focused based on the converging property given to the light reflected from the document by the image forming unit. And an optical path length matching means for optically correcting the position of the image reading means with respect to the determined position. 4. An image forming means for forming image information of the original document supported by the original document supporting means on a predetermined position as light and darkness of light, and an image of the original image formed on the predetermined position by the image forming means. An image reading unit for converting information into an electric signal corresponding to light and shade of light, a position arranged between the image forming unit and the image reading unit, and a position where light is formed by the image forming unit and the image reading unit. Optical path length matching means for optically matching the position of the light detection surface of the means, and holding means for holding the image forming means, the image reading means, and the optical path length matching means in a predetermined positional relationship, An image reading apparatus having. 5. An image forming means for forming image information of the original document supported by the original document supporting means on a predetermined position as light and dark of light, and an image of the original image formed on the predetermined position by the image forming means. An image reading unit that converts information into an electric signal corresponding to the light and shade of light; and a rear principal point of the image forming unit and the image reading unit, which are arranged between the image forming unit and the image reading unit. When the distance between them is L2, the focal length of the image forming means is f, and the magnification is m, the position where light is imaged by the image forming means and the position of the light detection surface of the image reading means are L2. = (M + 1) f + {(n-1) / n} d having a thickness d satisfying the following conditions: the position at which light is imaged by the image forming unit and the position on the light detection surface of the image reading unit. And an optical path length matching means that optically matches the image reading apparatus. 6. An image forming means for forming image information of the original document supported by the original document supporting means at a predetermined position as light and darkness of light, and an image of the original image formed at the predetermined position by the image forming means. An image reading unit for converting information into an electric signal corresponding to light and darkness of light, a position arranged between the image forming unit and the image reading unit, and a position where light is imaged by the image forming unit and the image reading unit. In an image reading apparatus having an optical path length matching means for optically matching the position of the light detection surface of the means, the output from the image reading means is output corresponding to the image of the document supported by the document supporting means. At least one of the refractive index and the thickness of the optical path length matching means is changed so that the signal matches a predetermined waveform. 7. A document supporting means for supporting a document, an illuminating means for illuminating the document supported by the document supporting means, and an image of the document by photoelectrically converting reflected light from the document illuminated by the illuminating means. An image reading unit that outputs an image signal corresponding to the image reading unit, an image forming unit that forms an image of the reflected light from the document illuminated by the illumination unit on the image reading unit, and has a predetermined thickness and refractive index. , At least between the image reading means and the image forming means, with respect to a position where the reflected light from the original is focused based on the focusing property given to the reflected light from the original by the image forming means. An image reading device having an optical path length matching device for optically correcting the position of the image reading device; and an image carrier for holding an electrostatic latent image corresponding to image information read by the image reading device, This statue A developing means for developing by supplying a developer to the electrostatic latent image held by lifting members, the image forming apparatus having. 8. A document supporting means for supporting a document, an illuminating means for illuminating the document supported by the document supporting means, and an image of the document by photoelectrically converting reflected light from the document illuminated by the illuminating means. An image reading unit that outputs an image signal corresponding to the image reading unit, an image forming unit that forms an image of the reflected light from the document illuminated by the illumination unit on the image reading unit, and has a predetermined thickness and refractive index. A focusing property given to reflected light from the original by the image forming means, which is arranged between the image reading means and the image forming means and between the image forming means and the document supporting means, or both. An image reading device having an optical path length matching means for optically correcting the position of the image reading means with respect to the position where the reflected light from the original is focused based on the image reading device, and the image information read by the image reading device. An image bearing member for holding an electrostatic latent image corresponding to, and developing means for developing by supplying a developer to the electrostatic latent image carried by the image carrier, the image forming apparatus having. 9. A document supporting means for supporting a document and image information of the document supported by the document supporting means,
Image forming means for forming an image at a predetermined position as light and dark of light, and image reading means for converting image information of an original image formed at a predetermined position by the image forming means into an electric signal corresponding to light and dark of light. An optical path length matching means which is arranged between the image forming means and the image reading means, and which optically matches the position where the light is imaged by the image forming means and the position of the light detection surface of the image reading means. And an image reading device having the image forming device, the image reading device, and a holding device for holding the optical path length matching device in a predetermined positional relationship, and a static image corresponding to the image information read by the image reading device. An image forming apparatus comprising: an image bearing member that holds an electrostatic latent image; and a developing unit that supplies a developer to the electrostatic latent image held by the image bearing member to develop the electrostatic latent image.