JP2003204422A - Image reader and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader that can obtain appropriate images in both fixed original reading and mobile original reading. <P>SOLUTION: This image reader is provided with two functions of a carriage reading function which reads the image of an original by moving the reader itself while the original is fixed, and a sheet through reading function which reads the image of the original while the original is moved and the reader itself is fixed to a prescribed position. This image reader is provided with an FGATE selecting circuit 21 which sets an effective image range in a subscanning direction for both functions and a white reference selecting circuit 22, and selects the effective image range or color reference plate reading range set by means of the circuits 21 and 22 based on a select signal 23 which select the range. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus provided with an automatic document feeder and an image forming apparatus, and more particularly to an image having a function of reading a fixed original and a function of moving the original. The present invention relates to a reading device and an image forming apparatus including the image reading device.

[0002]

2. Description of the Related Art There is known an image reading apparatus having an automatic document feeding apparatus, which has a function of fixing and reading a document and a function of moving and reading the document. Generally, in the image reading apparatus of the automatic document feeder type, the occupied area in the installation of the apparatus can be set small, and since the originals are continuously read, it is possible to improve the reading efficiency by repetitive work. However, it is not suitable for reading thick documents. In addition, the flatbed type image reading device can efficiently read thick documents such as magazines and books, but it occupies a large area in the installation of the device, and individual documents can be set individually. Therefore, the efficiency of reading by repetitive work cannot be improved. In a flatbed type image reading apparatus, the reading unit is made to stand by at the home position in preparation for starting reading, but the position sensor for setting the home position is a component independent of the document placing table and the reading unit on which the document is placed. To provide as
The reading start position depends on the position setting of the position sensor. Therefore, the positioning of the position sensor requires skill of an operator during assembly and adjustment.

From the above, for example, JP-A-11-0
The invention disclosed in Japanese Patent No. 88568 has been proposed. The present invention is characterized by selectively using carriage reading (scanning the document surface) and sheet through (automatic document feeder) scanning depending on the case. Specifically, 1) the basic configuration is an auto document feeder type. It has a flatbed type option unit separately. 2) The flatbed type optional unit is equipped with a reading unit removed from the automatic document feeder type image reading device as a basic configuration, and the original document feeding mechanism of the reading unit is used to perform scanning for reading in the flatbed type. Drive source. By adopting this means, the basic configuration takes the form of an automatic document feeder type, and continuously reads originals according to the specifications of single-cut sheets, and when necessary, switches to a flatbed type device by applying an optional unit. 3) Alternatively, the basic configuration of the image reading apparatus is a flatbed type, and separately has an auto document feeder type optional unit. 4) Attach the reading unit removed from the flatbed type image reading device as the basic structure to the optional unit of the automatic document feeder type described above, and use the moving mechanism of the reading unit to perform scanning for reading in the automatic document feeder type. Use as a driving source. As a basic configuration, it takes a flatbed type to read various types of originals, and switches to an automatic document feeder type device by applying an optional unit when necessary. 5) In the flat bed type image reading apparatus, a mechanism is formed in which the light irradiating the original is reflected by the reflecting means provided in a part of the original placing table and the light is directly guided to the CCD of the reading unit. , The position sensor of the reading unit. As a result, a position sensor for guiding the reading unit to the home position is directly formed on the document table. It has such characteristics.

[0004]

However, the above-mentioned prior art does not consider the difference in the settings of the image effective range and the white reference plate reading range when reading each of the carriage and the sheet through (document feeder). . Therefore, the read image data may be different between when the original is fixed and when the original is moved, and it may not be possible to obtain a proper image in both cases.

The present invention has been made in view of the above circumstances of the prior art, and an object thereof is to provide an image reading apparatus capable of obtaining an appropriate image for both fixed document reading and document moving reading. An object is to provide an image forming apparatus equipped with such an image reading device.

[0006]

In order to achieve the above object, a first means is a state in which an original is fixed in an image reading device which guides reflected light from the original to photoelectric conversion means and reads an image on the original surface. A document reading unit having a carriage reading function for reading an image while moving itself and a sheet-through reading function for reading an image of a moving document while the unit is fixed at a predetermined position, and a sub-reading unit for the document reading unit. It is characterized by comprising setting means for setting an image effective range in the scanning direction and selecting means for selecting the image effective range set by the setting means. According to this structure, the image effective range can be set in the reading operation of each function of the document reading unit, so that an appropriate image can be obtained regardless of which reading unit reads the image.

The second means is a carriage reading function of reading the image while the original is fixed in an image reading device for guiding the reflected light from the original to the photoelectric conversion means and reading the image on the surface of the original. And a document reading unit having a sheet-through reading function for reading an image of a moving document while itself is fixed at a predetermined position, and a setting unit for setting a white reference plate reading range of the document reading unit in the sub-scanning direction. And a selecting means for selecting the white reference plate reading range set by the setting means. According to this structure, since the white reference plate reading range can be set in the reading operation of each function of the document reading unit, an appropriate image can be obtained regardless of which reading unit the reading is performed.

The third means is characterized in that, in the first or second means, it further comprises means for previously storing a range selected by the selecting means for each applied device. With this configuration, since the effective image range or the white reference plate reading range selected by the selecting unit is stored, the reading range can be easily adjusted for each device based on the stored reading range.

A fourth means is characterized in that, in the first or second means, the document reading device includes a traveling body which travels in the sub-scanning direction. With this configuration, the document reading unit can move in the sub-scanning direction by the traveling body to read the document.

A fifth means is characterized in that, in the fourth means, the sheet through reading function of the document reading means is caused to function by stopping the traveling body at a predetermined position. With this configuration, one original reading unit can have both a carriage reading function and a sheet-through reading function.

A sixth means comprises an image reading device according to the first to fifth means and an image forming means for forming a visible image on a recording medium based on the image information read by the image reading device. The forming device is configured.

A document having a carriage reading function for reading an image while the document is fixed while the document is fixed and a sheet-through reading function for reading an image of the document while the document is fixed at a predetermined position. The document reading unit includes a reading unit and a setting unit that sets an image effective range and / or a white reference plate reading range of the document reading unit in the sub-scanning direction. The setting unit is suitable for each apparatus during a manufacturing process. The image effective range in the sub-scanning direction and / or the white reference plate reading range is adjusted, the adjustment result is stored in the memory, the adjustment result is read from the memory at the time of actual reading, and based on the read adjustment result. To set the image effective range and / or the white reference plate reading range in the sub-scanning direction of the document reading means. It can also be configured.

With this configuration, the effective image range and the white reference plate reading range are individually adjusted for each machine in the manufacturing process, and the adjustment results are stored. An appropriate image can be obtained based on the adjustment result.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an image forming apparatus (copier) PR having an original reading device as an image reading device according to an embodiment of the present invention. A general automatic document feeder 2 is attached to the document reading device 1, and a light source lamp 3, a first carriage (running body) 4, a second carriage (running body) 5, and an imaging lens are provided in the body of the document reading device. An optical system including a CCD 6 and a CCD 11 as a reading element is provided to read a document on the contact glass 7. The light source lamp 3 and the first mirror 8 are mounted on the first carriage 4, and the second mirror 9 is mounted on the second carriage 5.
Also, the third mirror 10 is mounted, and the reflected light of the document illuminated by the light source lamp 3 enters the imaging lens 6 via the first mirror 8, the second mirror 9 and the third mirror 10, and the imaging lens 6 An image signal is obtained by forming an image on the image forming surface of the CCD 11 and reading it by the CCD 11 to perform photoelectric conversion.

Based on such a reading optical system, the first carriage 4 and the second carriage 5 are moved to the right in FIG. 1 by a motor 12 as a driving source to read the entire original surface. This is fixed reading, and is also called carriage carriage reading because it reads by moving the first and second carriages 4 and 5. On the other hand, there is an automatic document feeder 2 (ADF-auto document feeder) on the contact glass, and the first and second carriages 4 and 5 of the main body of the document reader 1 are fixed at preset positions, and the light source lamp 3 Is turned on to read the original while the original is being conveyed from the automatic original feeding apparatus 2 is the original movement reading, that is, the sheet through reading. Normally, the former reading method is used for book originals for which the ADF 2 cannot be used, and the latter reading method is used for sheet originals.

The writing unit 57 is composed of a laser output unit 55, an imaging lens 59 and a mirror 60,
Inside the laser output unit 55, a laser diode that is a laser light source and a polygon mirror that rotates at a constant speed at a high speed by a motor are provided. The writing unit 57 converts (processes) the image data read by the document reading device 1 into image data for recording a visible image, and writes based on the converted image data.

The laser light emitted from the laser output unit 55 is deflected by the polygon mirror which rotates at a constant speed, passes through the imaging lens 59, is reflected by the mirror 60, and is condensed on the surface of the photosensitive member 15 to be combined. Image. The deflected laser light is exposed and scanned in a so-called main scanning direction orthogonal to the direction in which the photoconductor 15 rotates, and the image signal output by the image processing unit is recorded line by line. Then, an image, that is, an electrostatic latent image is formed on the surface of the photoconductor 15 by repeating main scanning at a predetermined cycle corresponding to the rotation speed of the photoconductor 15 and the recording density.

As described above, the laser light output from the writing unit 57 is applied to the photoconductor 15 of the image forming system. The laser light irradiation position near one end of the photoconductor 15 (not shown) is synchronized with the main scanning. A beam sensor for generating a signal is arranged. The image recording timing in the main scanning direction is controlled based on the main scanning synchronization signal output from the beam sensor, and a control signal for inputting / outputting an image signal described later is generated.

The transfer sheets stacked on the first tray 38, the second tray 39, and the third tray 40 are respectively transferred to the first sheet feeding device 3.
The sheet is fed by the first, second, and third sheet feeding devices 32, 33, and is transported by the vertical transport unit 14 to a position where it abuts on the photoconductor 15. The image data read by the document reading device 1 is written on the photoconductor 15 by the laser light from the writing unit 57, and passes through the developing unit 27 to form a toner image. For the transfer paper, the conveyor belt 1 is rotated at the same speed as the rotation of the photoreceptor 15.
While being conveyed by 6, the toner on the photoconductor 15 is transferred. Then, the fixing unit 17 fixes the image on the transfer paper, and the paper discharge unit 18 discharges the image onto the paper discharge tray 19 of the post-processing apparatus.

When images are formed on both sides of the transfer paper,
The transfer paper fed from each of the paper feed trays 38 to 40 is not guided to the paper discharge tray 19 side by setting the branching claw 112 for switching the path on the upper side, and the double-sided paper feed unit 111 is temporarily supplied. To the relevant unit 111
To stock. After that, the transfer paper stocked in the double-sided paper feeding unit 111 is sent again from the double-sided paper feeding unit 111 to the vertical transport unit 14 to transfer the toner image formed on the photoconductor 15, and is re-fed and transferred. After forming the image on the back side of the paper, set the reverse claw 112 to the lower side,
Guide to the paper discharge tray 19. The double-sided sheet feeding unit 111 is used when images are formed on both sides of the transfer sheet in this manner. Note that reference numeral 113 is a double-sided paper feed conveyance path, and reference numeral 114 is a reverse paper ejection conveyance path.

The photoconductor 15, the conveyor belt 16, the fixing unit 17, the paper discharging unit 18, and the developing unit 27 are driven by a main motor (not shown), and each paper feeding device 3 is driven.
1 to 33 are controlled by transmitting / disconnecting the driving force of the main motor by the sheet feeding clutch. The vertical transport unit 14 is controlled by transmitting the driving force of the main motor by an intermediate clutch.

By the way, in the document reading apparatus 1, when the image signal is outputted to the processing section in the subsequent stage, at the same time, the image effective range in the carriage moving direction (or the document feeding direction) is outputted as a signal (FGATE). This FGATE
In the case of carriage reading, it is the period from the image leading edge position on the document surface to the document trailing edge position determined by the document size.In case of sheet through, the document moves and the document leading edge is inserted at the reading position. It is a period corresponding to the time from the application of the document until the trailing edge of the document passes through the reading position.

Generally, sensitivity correction called shading correction is performed mainly for three reasons: 1) uneven sensitivity of each pixel of CCD, 2) uneven illumination of light source, and 3) focusing rule of lens.

This shading correction is performed by reading the white reference plate 13 and storing the white reference value in the memory of the control circuit (not shown) as shown in the schematic diagram of the vicinity of the white reference plate in FIG. Is corrected by calculating The white reference is a white reference plate 13 provided outside the original reading range in the case of carriage reading, and in the case of sheet through, it is provided behind the paper with respect to the reading optical system at the original reading position 7a and feeds the paper. The white roller 14 also serves as a document feeding roller. The timing chart of FIG. 3 shows the timing of FGATE and white reference reading in the case of carriage reading and sheet through.

Since the timings of reading these two types of FGATE or white reference are naturally different,
It is necessary to select which method to read each time. FIG. 4 is a block diagram showing a circuit configuration of a selection circuit for performing such selection.

The selection circuit 20 is an FGATE selection circuit 21.
And a white reference selection circuit 22. The FGATE 21a and the white reference signal 22a are input to the respective selection circuits 21 and 22. In response to these inputs, the FGATE selection circuit 21 selects the FGATE 21b for carriage reading and the FGATE 21c for sheet through reading. Any one of them also receives FGAT for carriage reading from the white reference selection circuit 22.
Either E22b or FGATE 22c for sheet through reading is output. In addition, the FGATE selection circuit 21
And the white reference selection circuit 22 is a selection signal 2 for either carriage reading or sheet through reading from a control circuit (not shown).
Selected by 3.

In the manufacturing process, the timing of FGATE or white reference is adjusted for each machine due to mechanical tolerance. In the case of FGATE, the original is actually read, the image is displayed on the display, and it is detected how much the leading edge or trailing edge is missing or left, and the timing of asserting or negating FGATE is advanced. Or slowing down. On the other hand, the white reference adjusts the assertion and negation of the white reference read signal while observing the image signal with an oscilloscope or the like.
In the present invention, the timing of FGATE or white reference is adjusted in each of the carriage reading and the sheet through in the manufacturing process, and the adjustment result is stored in the memory.
The TE selection circuit 21 and the white reference selection circuit 22 refer to the memory at each timing during actual reading, and output the FGATE or white reference signal. If there is little difference between machines in terms of white reference, it is not necessary to adjust each machine.

In the present embodiment, a document reading device using a CCD as a photoelectric conversion member is assumed, but this is not a limitation.

Although not described in detail here, these controls are performed by a CPU provided on a control board (not shown) of the image reading apparatus 1 in a RAM (not shown) according to a program stored in a ROM (not shown). It is executed while using it as a work area. Note that the control can be configured to be performed from the control circuit side of the image forming apparatus PR.

[0031]

As described above, according to the present invention, setting means for setting the image effective range of the first and second document reading means in the sub-scanning direction, and the image effective range set by the setting means. Or a setting means for setting the white reference plate reading range in the sub-scanning direction of the first and second document reading means and a white reference plate reading range set by the setting means. It is possible to provide an image reading apparatus and an image forming apparatus that can obtain an appropriate image for both fixed document reading and document moving reading.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus including a document reading device as an image reading device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration near a white reference plate in FIG.

FIG. 3 is a timing chart showing timings of FGATE and white reference reading in the case of carriage reading and sheet through reading according to the embodiment of the present invention.

FIG. 4 is a block diagram showing a circuit configuration of a selection circuit for carriage reading and sheet through reading according to the embodiment of the present invention.

[Explanation of symbols]

1 Document reading device 4 First carriage 5 Second carriage 7a Reading position 11 CCD 12 motors 14 White roller 15 photoconductor 20 selection circuit 21 FGATE selection circuit 22 White reference selection circuit 23 Selection signal 27 Development unit 31, 32, 33 paper feeder 34 Vertical transport path 38, 39, 40 paper feed tray 57 Writing unit PR image forming apparatus body

Claims (6)

[Claims] 1. An image reading apparatus for reading reflected light from a document to photoelectric conversion means to read an image on the surface of the document. A carriage reading function for reading an image while moving the document while the document is fixed and a predetermined function are provided. An original reading unit having a sheet-through reading function for reading an image of a moving original in a state of being fixed in a position, a setting unit for setting an effective image range in the sub-scanning direction of the original reading unit, and the setting unit. An image reading apparatus comprising: a selection unit that selects the set effective image range. 2. An image reading device for reading the image on the surface of an original by guiding reflected light from the original to photoelectric conversion means, and a carriage reading function for reading the image while moving the original while the original is fixed and a predetermined function. An original reading unit having a sheet-through reading function for reading an image of a moving original while being fixed at a position; a setting unit for setting a white reference plate reading range in the sub-scanning direction of the original reading unit; An image reading apparatus comprising: a selection unit that selects a white reference plate reading range set by the unit. 3. The image reading apparatus according to claim 1, further comprising means for storing in advance a range selected by the selecting means for each applicable apparatus. 4. The image reading apparatus according to claim 1, wherein the document reading unit includes a running body that runs in the sub-scanning direction. 5. The image reading apparatus according to claim 4, wherein the sheet through reading function of the document reading unit is made to function by stopping the traveling body at a predetermined position. 6. The image reading device according to claim 1, and an image forming unit that forms a visible image on a recording medium based on image information read by the image reading device. An image forming apparatus characterized by being provided.