JPH05300332A - Picture reader - Google Patents

Abstract

PURPOSE:To improve the productivity without increase in a capacity of a power supply by controlling a scanner so as to start the movement in the direction of a home position after an automatic draft feeder starts carrying a succeeding original when the scanner reads a preceding original. CONSTITUTION:A control unit has a CPU 601 controlling the sequence relation and a main CPU controlling the operation relation and is mounted to a main control board. The CPU 601 implementing the control of the sequence relation executes a condition setting output relating to paper timing and image forming and has a paper size sensor 603 and sensors 603a relating to carrying of paper such as paper discharge detection and resist detection. When the original carried by an automatic draft feeder is read by a scanner, after the automatic draft feeder starts carrying of a succeeding original, since the scanner starts movement in the direction of home position, the replacement time of the originals is reduced and the productivity is improved without increasing the capacity of the power supply.

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 capable of mounting an automatic document feeder (ADF) for feeding originals one by one onto a contact glass.

[0002]

2. Description of the Related Art An ADF is generally used in, for example, a copying machine to improve copy productivity (CPM: Copy Per Minute). CPM when using this ADF
Is determined by the document feed time for conveying one document on the contact glass and the scanning time in the forward direction of the scanner for reading the document image. A technique for improving this CPM is disclosed in, for example, Japanese Patent Laid-Open No. 1-236136. Japanese Patent Laid-Open No. Hei 1-236137.

However, when the originals are replaced during the return time of the scanner, the transient current of the scanner motor and the transient current of the ADF transport motor for replacing the originals overlap each other. A voltage drop etc. occurs due to insufficient capacity. Further, if the capacity of the power supply is increased to solve this problem, the cost will increase and the device will also become large.

FIG. 20 shows the control timing of the conventional image reading apparatus. In this conventional example, first, one original is conveyed onto the contact glass by the ADF at the original feed time x, and then the scanner is moved in the forward direction at the scanning time y to read the original image. Then, after the movement of the scanner in the return direction is started and the delay time z of usually 300 ms elapses so that the transient currents do not overlap with each other, A
It is configured to start document replacement of the DF. Therefore, the CPM in this case is 60 / (x + y + z)
Becomes

[0005]

However, in the above-mentioned conventional image reading apparatus, in order to prevent the transient current of the scanner motor and the transient current of the ADF transport motor for document replacement from overlapping, the return current of the scanner is changed. Since the document replacement of the ADF is started after the start of the movement and the delay time z has elapsed, there is a problem that the CPM cannot be improved.

In view of the above-mentioned conventional problems, it is an object of the present invention to provide an image reading apparatus capable of improving productivity without increasing the capacity of a power source.

[0007]

In order to achieve the above-mentioned object, a first means is an image reading device for reading a document conveyed by an automatic document feeder by a scanner, in the case where the scanner reads a previous document. In addition, the automatic document feeder is provided with control means for controlling the scanner to start moving toward the home position after the conveyance of the next document is started.

According to a second means, when the control means of the first means reads a document conveyed by the automatic document feeder and when a document placed on the contact glass is read, the scanner is at the home position. The control is performed such that the timing of starting the movement in the direction of is different.

[0009]

In the first means, according to the above-mentioned structure, when the original document conveyed by the automatic original document feeder is read by the scanner, the automatic original document feeder starts to convey the next original document when the scanner reads the previous original document. After that, since the scanner starts moving toward the home position, it is possible to shorten the time for replacing the originals, and thus improve the productivity without increasing the capacity of the power supply.

In the second means, the timing at which the scanner starts moving toward the home position when reading the original placed on the contact glass is different, so that the production is performed even when the automatic original feeding device is not used. Sex does not deteriorate.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a control unit of a digital copying machine which is an embodiment of an image reading apparatus according to the present invention, and FIG. 2 is a block showing an entire circuit configuration of a digital copying machine using the control unit of FIG. 3 is a side view showing the overall structure of the digital copying machine, FIG. 4 is a plan view showing the detailed structure of the writing unit shown in FIG. 3, FIG. 5 is a side view showing the writing unit shown in FIG. 4, and FIG. 6 is an image. FIG. 7 is a block diagram showing the scanner unit in detail, FIG. 7 is a block diagram showing the detailed configuration of the image process unit of FIG. 6, FIG. 8 is an explanatory diagram showing the data depth switching operation of the image process unit of FIG. 7, and FIG. A block diagram showing a memory system using the image processing unit of FIG. 6, FIG. 10 is an explanatory diagram showing an operation of a general memory system, FIG. 11 is an explanatory diagram showing an operation of the memory system of FIG. 9, and FIG. 13 is a block diagram showing another memory system, FIG. 13 is a block diagram showing a detailed configuration of the memory unit of FIG. 12, FIG. 14 is an explanatory diagram showing processing data of the memory unit of FIG. 13, and FIG. 15 is a memory of FIG. 17 is a block diagram showing a modified example of the system, FIG. 16 is a block diagram showing another modified example of the memory system of FIG. 12, and FIG.
18 is a block diagram showing another modification of the memory system of FIG. 16, FIG. 18 is a timing chart for explaining the operation in the ADF mode of this embodiment, and FIG. 19 is the ADF transport timing and scanner scanning in FIG. It is a timing chart which shows a timing.

In FIGS. 1A and 1B, this control unit includes a CPU 601 for controlling sequence-related operations,
It has a main CPU 602 that controls operations, and the CPUs 601 and 602 are mounted on a main control board 700 as shown in FIG. A CPU 601 which controls sequence-related settings sets and outputs conditions for paper conveyance timing and image formation, and as shown in FIG. 1B, a paper size sensor 603 and paper conveyance such as paper discharge detection and registration detection. Related sensors 603a, a duplex unit 604, a high-voltage power supply unit 605, a driver 606 such as a relay, a solenoid, a motor, and a laser beam scanner unit 608 are connected. The laser beam scanner unit 608 is connected to the image control circuit 609, and the image control circuit 609 is composed of the circuits shown in FIGS. 2 and 6 to 9.

The paper size sensor 603 detects the size and orientation of the transfer paper loaded in the paper feed cassette, and the sensors 6
In addition to paper discharge detection and resist, 03a detects the presence or absence of supplies such as oil end and toner end, and mechanical abnormalities such as door open and fuse blown. Duplex unit 6
Reference numeral 04 has a motor for aligning the width of the paper and a side fence home position sensor, a paper feed clutch, a solenoid for changing the transport path, a paper presence / absence detection sensor, and a sensor for transporting the paper.

The high-voltage power supply unit 605 applies high-voltage power to the charging charger 41, the transfer charger 44, the separation charger 45, and the bias electrodes of the developing devices 42a and 42b shown in FIG. Is applied. The driver 606 includes a paper feed clutch, a registration clutch, a counter, a motor, a toner replenishing solenoid, a power relay, a fixing heater, and the like. The sorter unit (III) 607 has a CPU 6
01 is connected via a serial interface, and the paper is conveyed at a predetermined timing by a control signal from the CPU 601 and discharged to each bin.

As the analog signal input to the CPU 601, a detection signal of the photosensor 50 for fixing temperature and density as shown in FIG. 3 and a monitor current and reference voltage of the laser diode 20 as shown in FIG. 4 are input. To do. The fixing temperature is detected by the thermistor of the fixing mechanism (rollers 64, 65), and the heater is on / off controlled or phase controlled so as to be constant. Photosensor 50 for density detection
The detection signal is detected by reading a pattern formed on the photoconductor 40 with a phototransistor at a predetermined timing, the toner supply clutch is turned on and off, and the toner end is detected. The monitor current of the laser diode 20 is a reference voltage (for example, 3 m).
W) is controlled to match.

Next, the main CPU 602 which controls the operations will be described.
U602 has multiple serial ports and calendar IC61
0 is also controlled, and as shown in FIGS. 2 and 6 to 9, the quantization parameter is changed for each document according to the document size and the scaling factor. The CPU 601 has a plurality of serial ports.
In addition to the operation unit 611 and the scanner control circuit 6
12, an application unit 613, an editor unit 614, etc. are connected.

The operation unit 611 has a key input device for the operator and a display for displaying the status of the copying machine, and notifies the main CPU 602 of the key input information by serial communication. The main CPU 602 determines whether the indicator of the operation unit unit 611 is on or off based on this key input information, and notifies the operation unit unit 611 of a display command by serial communication. The operation unit 611 turns on or off the display according to this display command. Scanner control circuit 61
2 is a main CPU for serially communicating information related to drive control of the scanner servo motor, image processing, and image reading.
602, ADF (II) and main CPU 60
Interface processing between the two.

The application unit 613 performs interface processing between an external device such as a facsimile or an external printer and the main CPU 602, and exchanges predetermined information. The editor unit 614 transmits image editing data such as masking, trimming, and image software input by the operator to the main CPU 602 by serial communication.
The calendar IC 610 stores the current date and time and informs the main CPU 602 at any time. Therefore, the calendar IC 610 displays the current time on the display of the operation unit 611 and controls the on-time and off-time of the copying machine with a timer. You can

The gate array 615 is the main CPU 60.
Image data is selectively output from the scanner control circuit 612 to the image control circuit 609, from the scanner control circuit 612 to the application unit 613, or from the application unit 613 to the image control circuit 609 in response to the select signal from 2. When output from the scanner control circuit 612 to the image control circuit 609, 8-bit image data from the scanner is transmitted in synchronization with the synchronization signal PMSYNC from the laser beam scanner unit 608. When output from the scanner control circuit 612 to the application unit 613, a 1-bit (binary) signal from the scanner is output, and when output from the application unit 613 to the image control circuit 609, 1-bit (binary) signal is output. The signal is transmitted in synchronization with the synchronization signal PMSYNC.

Next, the details of the digital copying machine to which the image reading apparatus of this embodiment is applied will be described with reference to FIGS. In FIG. 3, this digital copying machine is roughly configured by four units, a copying machine main body (I), an automatic document feeder (ADF) (II), a sorter (III) and a double-sided reversing unit (IV). Has been done. The copying machine main body (I) includes a scanner unit, a writing unit, a photoconductor unit, a developing unit, a paper feeding unit, and the like, which will be described in detail below.

The scanner unit is equipped with a reflecting mirror 1, a fluorescent lamp 3 as a light source, and a first mirror 2, and a first scanner which moves in a sub-scanning direction at a constant speed, a second mirror 4 and a third mirror. The second scanner 5 is attached and moves in the sub-scanning direction at a speed half that of the first scanner. A document (not shown) on the contact glass 9 is optically scanned by the first scanner and the second scanner, and the reflected light thereof is transmitted through the color filter 6 and the lens 7 to the light receiving surface of the one-dimensional solid-state imaging device 8. Is imaged.

A CCD image sensor is generally used as the solid-state image pickup device 8. Since the image signal read by the solid-state image sensor 8 is analog, it is A / D converted, and binarized and multi-valued gradation processing is performed by the processing circuits shown in FIGS. 1, 2, and 6 to 9. , Various processing such as scaling processing and editing are performed. In order to obtain a color signal, a color filter 6 is arranged so that it can be freely moved in and out of the optical path, and this color filter 6 is also moved in and out of the optical path in accordance with the scanning of an original to perform various types of copying such as multiple transfer and double-sided copying. Is done.

The image information after the image processing is shown in FIGS.
By the raster scanning of the laser light of the writing section as shown in detail in FIG. The laser light emitted from the semiconductor laser 20 is shaped into a parallel light flux by the collimator lens 21, passes through the aperture 32, is shaped into a uniform light flux, and is then compressed in the sub-scanning direction by the first cylinder lens 22. The light enters the reflecting surface of the polygon mirror 24 through the dustproof glass 23.

The polygon mirror 24 is formed in an accurate polygon and is rotated by a polygon motor 25 in a predetermined direction at a constant speed. The rotation speed is determined by the rotation speed of the photoconductor 40, the writing density, and the number of faces of the polygon mirror 24. The laser light incident on the reflecting surface of the polygon mirror 24 is deflected at a constant angular velocity, and then corrected by the f-θ lenses 26a and 26b so that the photoconductor 40 is scanned at a constant velocity. The f-θ lenses 26a and 26b
Also has a trouble correction function.

The laser light corrected by the f-θ lenses 26a and 26b is guided outside the image area by the synchronization detection mirror 29 to the synchronization detection light input section 30 and is guided to the sensor by the optical fiber. Then, after a predetermined time from the cue signal in the main scanning direction synchronized with this detection signal, image data for one line is output and guided to the photoconductor 40 side by the mirror 27. Hereinafter, by repeating this operation, an electrostatic latent image of one image is formed on the photoconductor 40.

A photoconductor layer is formed on the peripheral surface of the photoconductor 40. An organic photoconductor (OPC) is used as a photoconductor layer having sensitivity to a semiconductor laser having a wavelength of 780 nm.
Although α-Si and Se-Te are known, an organic photoconductor (OPC) is used in this embodiment. Here, when writing with the semiconductor laser 20, two types are known: a negative / positive process of irradiating the image portion with light and a positive / positive process of irradiating the background portion with light. Writing is done by a positive process.

In FIG. 3, the charging charger 41 uses a scorotron system having a grid on the side of the photoconductor 40, uniformly charges the surface of the photoconductor 40 (-), and irradiates an image forming area with laser light. Reduce the potential of the area. Therefore, the potential of the background area of the photoconductor 40 is -7.
50 to -800V, while the image area potential is -5
Since it is about 00V, an electrostatic latent image is formed on the surface of the photoconductor 40.

The developing units 42a and 42b are connected to the developing roller.
A bias voltage of 500 to -600V is applied, and (-)
The charged toner is attached to the image area of the photoconductor 40 to visualize the electrostatic latent image. The developing unit of the present embodiment includes two main developing devices 42a and sub-developing devices 42b.
The toner replenishing device 43a corresponding to 2a is filled with black toner, and the toner replenishing device 43b corresponding to the sub-developing device 42b is filled with color toner, whereby selective development can be performed.

The transfer sheet is conveyed to the position of the transfer charger 44 in synchronism with the toner image on the photoconductor 40, and is transferred to the developing device 4.
The toner images visualized by 2a and 42b are transferred to the transfer paper by the transfer charger 44 charging the back surface of the transfer paper to (+). The transfer paper on which the toner image has been transferred is subjected to AC charge removal by the separation charger 45, and the photosensitive member 4
Separated from zero. The toner remaining on the photoconductor 40 is removed by the cleaning blade 47 and collected in the tank 48. The residual charge on the photoconductor 40 is removed by the charge removal lamp 49 irradiating the photoconductor 40.

A photo sensor 5 for detecting the reflection density on the photoconductor 40 is provided downstream of the developing units 42a and 42b.
0 is provided, and the photosensor 50 reads the density of a pattern such as black or halftone dots formed by the writing unit and developed and the density other than this pattern, and detects the density of the toner image to detect light The toner replenishment signal is output to or the toner remaining amount shortage signal is output to.

The paper feeding unit is composed of a plurality of cassettes 60a, 60.
b, 60c, and is configured to perform double-sided copying and sheet re-feeding by guiding the sheet once transferred to the transfer position via the sheet re-feeding loop 72. When the copy start button is pressed after one of the cassettes 60a, 60b, 60c is selected, the corresponding paper feed roller 61a,
One of the rollers 61b and 61c rotates, and the transfer sheet is conveyed until its leading end abuts the registration roller 62. Then, the registration roller 62 starts rotating so that the toner image on the photoconductor 40 and the transfer sheet are synchronized, and the above-described transfer is performed.

The transfer sheet separated from the photoconductor 40 is sucked and conveyed by the separation conveying section 63, and the fixing roller 6
The toner image is fixed by 4, 65. Then, this transfer sheet is guided to the discharge port on the sorter (III) side in the case of normal single-sided copying, and in the case of multiplex copying without changing the copy surface by the switching claws 67, 68, 69. It returns to the position of the registration roller 62 via the lower re-feeding loop 72. In the case of double-sided copying, the copy surface is reversed by the copying machine body (I) or the double-sided reversing unit (IV). In the former case, the switching claws 68, 69, 71
Is guided to the tray 70 below the re-feeding loop 72 and is returned in the opposite direction by reversing the roller 71.
Switching to the sheet re-feeding loop 72, the sheet is inverted and returned to the position of the registration roller 62.

The ADF (II) is configured to automatically convey the originals one by one onto the contact glass 9 and eject the originals from the contact glass 9 after reading. Specifically, the document stack placed on the document feed tray 100 is aligned in the width direction by the side guides 101, and is fed by the feed rollers 104.
Are separated and taken in by each. Separation roller 1
The original passing through 04-1 has its original size detected by registration detection, original width detection, and original length detection by a pulse generator, and is conveyed and positioned on the contact glass 9 by rotation of the conveyor belt 102, and reading is completed. Then, the conveyance belt 102 is driven to discharge the sheet onto the sheet discharge tray 103. Note that the size of the document can be counted by counting the position of the side guide 101 and the document feeding time. The timings of carrying and discharging the original are controlled by driving the carrying motor and the paper discharging motor 701 shown in FIG.

The sorter (III) is configured to selectively discharge the transfer paper discharged from the copying machine main body (I), for example, in page order, page by page, or to preset bins 111a to 111x. .. In this case, the transfer paper is conveyed by a plurality of rollers that are rotated by the motor 110, and the bin 11 is moved by the switching claws arranged near the inlet of each bin.
1a to 111x.

The double-sided reversing unit (IV) is used when reversing the front and back sides of a plurality of transfer papers for double-sided copying.
In this case, the transfer paper inside the copying machine main body (I) is the discharge roller 6
It is guided downward by 6 and is guided to the double-sided reversing unit (IV) by the next switching claw 68. Then, the discharge roller 1
The sheets 20 are stacked on the tray 123, and are vertically and horizontally aligned by the feed roller 121 and the side surface alignment guide 122. The transfer sheets accumulated on the tray 123 are returned to the inside of the copying machine main body (I) by the re-feed roller 124, and are directly guided to the re-feed loop 72 by the switching claw 69.

In FIG. 6, the analog image signal read by the CCD image sensor 8 is the signal processing circuit 4 in the image preprocessors (IPP) 451 to 453.
Amplification and light amount correction are performed at 51, and the digital multilevel signal is converted at the A / D converter 452. The shading correction circuit 453 corrects the unevenness of light amount and the error of the CCD image sensor 8 to the digital multi-level signal, and the image process unit (IPU) 50 as shown in detail in FIG.
It is output to 0.

In the IPU 500 shown in FIG. 7, this digital multilevel signal is high-frequency emphasized by the MTF correction circuit 501, scaled by the scaling circuit 502, and the γ conversion circuit 503.
Is converted so that the gradation input / output characteristics are optimized,
Then, this signal is the switch SW of the data depth switching mechanism.
1 selectively converts into four quantization levels.
The 4-bit conversion circuit 504 converts an 8-bit signal as shown in FIG. 8A into 4-bit data as shown in FIG. 8B, and the binarization circuit 505 is shown in FIG. 8A. Like 8
The bit signal is converted into 2-bit data as shown in FIG. 8C, and the dither circuit 506 generates an area gradation with 1 bit from the 8-bit signal as shown in FIG. 8A.
The switch SW2 is a binarization circuit 505 or a dither circuit 5
The output signal No. 06 is selected and output via the switch SW1.

Returning to FIG. 6, the scanner control circuit 460 follows the instruction from the printer control circuit and the fluorescent lamp ballast 45.
8. Controls the timing control circuit 459, the scaling circuit 502 of the IPU 500, and the scanner drive motor (M) 465. The fluorescent light ballast 458 controls on / off and the amount of light of the fluorescent light 3 according to an instruction from the scanner control circuit 460. A rotary encoder 466 is connected to the drive shaft of the scanner drive motor 465, and the position sensor 462 is used to detect the reference position (home position) of the sub-scanning mechanism. The scaling circuit 502 electrically scales according to the magnification data in the main scanning direction set by the scanner control circuit 460.

The timing control circuit 459 outputs various signals in accordance with instructions from the scanner control circuit 460, and when reading is started, for example, a transfer for transferring one line of data to the CCD image sensor 8 to the shift register. A signal and a shift clock pulse for outputting the data of the shift register bit by bit are output. The timing control circuit 459 also outputs a pixel clock pulse CLK, a main scanning synchronization pulse LSYNC, a main scanning effective period signal LGATE and a sub-scanning effective period signal FGATE to the control unit of the image reproduction system.

Here, the pixel clock pulse CLK is C
The signal is almost the same as the shift clock pulse applied to the CD image sensor 8. Also, the main scanning synchronization pulse L
SYNC is almost the same signal as the main scanning synchronization signal PMSYNC output from the beam sensor of the image writing unit, but is output in synchronization with the pixel clock pulse CLK.
The main scanning effective period signal LGATE is output data DATA0.
~ DATA7 goes high at the timing when it is considered to be valid data. The CCD image sensor 8
Is configured to output, for example, valid data of 4800 bits per line.

When the scanner control circuit 460 receives a reading start instruction from the printer control circuit, it turns on the fluorescent lamp 3, starts driving the scanner drive motor 465, controls the timing control circuit 459, and controls the CCD image sensor 8.
To start reading. Further, the sub-scanning effective period signal FGATE is set to the high level, and is set to the low level when the time required to scan the maximum reading length in the sub-scanning direction (for example, the dimension in the A size longitudinal direction) elapses.

In the memory system shown in FIG. 9, the signals processed by the above-mentioned IPPs 451 to 453 are selected by the multiplexer 511 and the above-mentioned IPU 500 is selected.
Are processed by the multiplexer 512, selected by the multiplexer 512, and output to the printer unit (PR). Also, IPU50
The signal before being processed by 0, the processed signal, and the signal from the outside such as a facsimile are transmitted to the multiplexer 513.
Can be stored in the memory (MEM) 514 via the multiplexer 512.
It is also possible to output to the printer unit via the, or output again to the IPU 500 via the multiplexer 511 for processing.

That is, in a digital copying machine using a memory, as shown in FIG. 10, the signal processed by the IPU 500 is usually output directly to the printer unit or the memory 51.
The second and subsequent sheets are copied by temporarily storing them in the No. 4 and outputting them to the printer section. In the circuit example shown in FIG.
As shown in, the parameter can be changed in one reading to make a plurality of copies. In the case of simple data such as 1-bit data, the signal processed by the IPU 500 can be fetched in the memory 514 and the printer unit can be switched to the binary data mode for copying.

Further, as shown in FIGS. 12 to 14, a compressor (COMP) is provided before and after the memory unit 520, respectively.
515 and multiplexer 516 and expander (EX
P) 517 and multiplexer 518 may be provided and configured to store actual or compressed data in memory unit 520. In this case, the compressor 515 needs to operate according to the speed of the scanner, and the decompressor 517 needs to operate according to the speed of the printer.
As shown in FIG. 4, three types of image data of 8 bits, 4 bits and 1 bit, and data width converters 522 and 523 for processing code data which is compressed data are provided before and after the memory block 521, respectively. .. The direct memory access controller (DMAC
1, DMAC2) 524 and 525 are configured to write and read data to and from a predetermined address of the memory according to the number of data packed and unpacked and the data width by the data width converters 522 and 523, respectively. ..

Here, the speed of the image data from the scanner or the image data to the printer is 8 bits,
It is constant regardless of 4 bits or 1 bit, and the period of 1 pixel is fixed in the device. The input data width converter 522 converts each data of eight data lines from the most significant bit MSB to 1-bit data, 4-bit data,
The memory block 52 is packed and packed according to 8 bits.
Output to 1. The output data width converter 523 unpacks the packed data into the original data. Therefore, the memory block 521 can be effectively used according to the data depth.

In the memory system 530 shown in FIG. 15,
A pixel process unit (PPU) 532 is provided outside the memory unit 531 instead of the compressor 515 and the decompressor 517 shown in FIG. This PPU 532 is a logical operation (for example, AN
D, OR, EOR, NOT) and multiplexer 5
The data is output to the printer unit via 34 or stored in the memory unit 531 via the multiplexer 533. In this memory system 530, overlay data can be stored in the memory unit 531 in advance, and the PPU 532 can superimpose the overlay data and the scanner data.

The memory system 540 shown in FIG. 16 is configured to store image data from an external storage device. Image data to floppy disk (F
D) When the image data from the external storage device is stored in the I / F 541 and the floppy disk controller (FD) under the control of the file controller 548.
C) Floppy disk drive device (F
DD) 543 is output. The memory system 540 also includes a hard disk controller (HDC) 5
46 and a hard disk drive (HDD) 547 are provided, and image data from an external storage device can be stored in the hard disk. It should be noted that the hard disk can store format data and overlay data which are frequently used and can be read out as necessary. Also,
Reference numeral 545 is a line drawer.

The memory system 550 shown in FIG. 17 is configured to cope with a case where the processing speeds of compression and decompression are not in time. The image data at the time of scanning by the scanner is stored in the memory unit 552, compressed by the compressor 551 and stored in another area of the memory unit 552, and the compressed data is expanded by the expander 553 and passed through the multiplexer 554. Output to the printer section. All data on one page is in memory unit 55
If the processing of the compressor 551 and the decompressor 553 ends normally before being stored in 2, the compressed data is stored in the memory unit 552 and the raw data is deleted. On the other hand, when the error detection circuit 556 detects an error signal from the compressor 551 or the decompressor 553, the compressed data is immediately canceled and the raw data is selected.

The memory management unit (MMU) 555 is
Two input data are stored in the memory unit 552,
It controls so that one output data is read from the memory unit 552. Therefore, according to the memory system 550, the compression and decompression processes are inspected.
It is possible to realize high speed and certainty of data.
The area of the memory unit 552 can be effectively used. Instead of controlling the writing and reading of data by the memory management unit 555, two memory units for raw data and compressed data may be provided. In addition, the memory system 550 is most suitable for applications in which the number of stored pages and the printer speed must be compatible, such as in the case of storing a plurality of pages and outputting them to the printer in real time, such as electronic sorting. ..

Next, the operation in the ADF mode of the above embodiment will be described with reference to FIGS. 18 and 19. When the scanner returns to the home position and is ready for copying, the process proceeds from step S1 to step S2, and when the print button is pressed, the process proceeds from step S2 to step S3.
When the document is set on the ADF (II), the process proceeds from step S3 to step S4, and the current document is controlled to be fed into the contact glass 9.

In the following step S5, the feed-in timing of ADF (II), which is the timing of starting the conveyance of the next document, is calculated, and in step S6, the return timing is calculated to return the scanner to the home position after the reading is completed. Here, the feed-in timing is the return timing of the scanner in the conventional example as shown in FIG. 19, and corresponds to the scanning distance A in the forward direction.
The scanning distance A is the length of the transfer paper when the copy magnification is equal to or less than 100% or is reduced, and is the length / magnification of the transfer paper when the copy magnification is 101% or more. is there. That is, the feed-in timing is the position of the A / B pulse from the movement start of the scanner when the scanner scans the distance B by one pulse of the encoder.
On the other hand, the return timing of the scanner is a timing delayed by the delay time z from the feed-in timing of the next document. That is, when the magnification is 100%,
When the time for scanning one pulse of the encoder is C, the return timing of the scanner is (feed-in timing + z / C) pulses.

In the subsequent step S7, it is determined whether or not the original document is set at a predetermined reading position on the contact glass 9, and if it is set, the scanner is moved in the forward direction (step S8), and the above-mentioned operation is performed. Image reading processing is performed (step S9). Then, it is determined whether or not it is the feed-in timing of the next document (step S10), and if it is that timing, the process proceeds to step S11. When the original document of this time is read again in step S11, the process branches to step S12, the scanner is moved in the return direction, and the scanner returns to the home position (step S11).
13) The scanner is stopped (step S14), and when the movement start timing of the scanner in the forward direction comes (step S15), the process returns to step S8 to read the original document again.

On the other hand, in the case of the last copy in which the original is not read again in step S11, step S11
When the document is set in the ADF (II) (step S17), the process is controlled so that the current document is fed out and the next document is fed in on the contact glass 9 (step S18). ). Next, it is judged whether or not it is the return timing of the scanner, and if it is that timing, steps S18 to S19
When the scanner is moved in the return direction to return to the home position (step S20), the scanner is stopped (step S21), and the process returns to step S7.

In step S16, ADF (II)
If the next original is not set in, the scanner is immediately moved in the return direction (step S22), and when the scanner returns to the home position (step S23),
The scanner is stopped (step S24).

Therefore, according to the above embodiment, the ADF
When the originals are conveyed and read one by one according to (II), the feed-in of the next original is started first, and then the scanner is moved in the return direction, so that the productivity of copying can be improved. In addition, since the feed-in of the next document and the start of the scanner return do not overlap, a large capacity power supply is not required.

When the ADF mode is not set, that is, when the document is manually placed, the scanner is returned at the feed-in timing in the ADF mode.
CPM does not deteriorate.

[0057]

As described above, according to the first aspect of the present invention, in the image reading device for reading the document conveyed by the automatic document feeding device by the scanner, the automatic reading is performed when the scanner reads the previous document. Since the document feeding device is provided with the control means for controlling the scanner to start moving toward the home position after the next document is started to be conveyed, the document replacement time can be shortened. The productivity can be improved without increasing the capacity of the power supply.

According to a second aspect of the invention, the scanner is used when the control means according to the first aspect reads an original document conveyed by an automatic original document feeder and when an original document placed on a contact glass is read. Since the control is performed such that the timing of starting the movement toward the home position is different, the productivity does not deteriorate even when the automatic document feeder is not used.

[Brief description of drawings]

FIG. 1 is a block diagram showing a control unit of a digital copying machine which is an embodiment of an image reading apparatus according to the present invention.

2 is a block diagram showing an overall circuit configuration of a digital copying machine using the control unit of FIG.

FIG. 3 is a side view showing the overall configuration of a digital copying machine.

FIG. 4 is a plan view showing a detailed configuration of a writing unit shown in FIG.

5 is a side view showing the writing unit of FIG. 4. FIG.

FIG. 6 is a block diagram showing in detail an image scanner unit.

7 is a block diagram showing a detailed configuration of the image process unit of FIG.

8 is an explanatory diagram showing a data depth switching operation of the image process unit of FIG.

9 is a block diagram showing a memory system using the image processing unit of FIG.

FIG. 10 is an explanatory diagram showing an operation of a general memory system.

FIG. 11 is an explanatory diagram showing an operation of the memory system of FIG. 9.

FIG. 12 is a block diagram showing another memory system.

13 is a block diagram showing a detailed configuration of the memory unit of FIG.

FIG. 14 is an explanatory diagram showing processing data of the memory unit of FIG.

15 is a block diagram showing a modified example of the memory system of FIG.

16 is a block diagram showing another modification of the memory system of FIG.

17 is a block diagram showing another modification of the memory system of FIG.

FIG. 18 is a timing chart for explaining the operation of this embodiment in the ADF mode.

FIG. 19 is a timing chart showing the transport timing of the ADF and the scanning timing of the scanner in the operation of FIG.

FIG. 20 is a timing chart showing ADF transport timing and scanner scanning timing in a conventional example.

[Explanation of symbols]

 II ADF (Automatic Document Feeder) 465 Scanner Motor 601 CPU (Central Processing Unit) 701 ADF Conveyance / Discharge Motor

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] October 26, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Detailed explanation of the invention

[Correction method] Change

[Correction content]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus capable of mounting an automatic document feeder (ADF) for feeding originals one by one onto a contact glass.

[0002]

2. Description of the Related Art An ADF is generally used in, for example, a copying machine to improve copy productivity (CPM: Copy Per Minute). CPM when using this ADF
Is determined by the document feed time for conveying one document on the contact glass and the scanning time in the forward direction of the scanner for reading the document image. A technique for improving this CPM is disclosed in, for example, Japanese Patent Laid-Open No. 1-236136. Japanese Patent Laid-Open No. Hei 1-236137.

However, when the originals are replaced during the return time of the scanner, the transient current of the scanner motor and the transient current of the ADF transport motor for replacing the originals overlap each other. A voltage drop etc. occurs due to insufficient capacity. Further, if the capacity of the power supply is increased to solve this problem, the cost will increase and the device will also become large.

FIG. 24 shows the control timing of the conventional image reading apparatus. In this conventional example, first, one original is conveyed onto the contact glass by the ADF at the original feed time x, and then the scanner is moved in the forward direction at the scanning time y to read the original image. Then, after the movement of the scanner in the return direction is started and the delay time z of usually 300 ms elapses so that the transient currents do not overlap with each other, A
It is configured to start document replacement of the DF. Therefore, the CPM in this case is 60 / (x + y + z)
Becomes

[0005]

However, in the above-mentioned conventional image reading apparatus, in order to prevent the transient current of the scanner motor and the transient current of the ADF transport motor for document replacement from overlapping, the return current of the scanner is changed. Since the document replacement of the ADF is started after the start of the movement and the delay time z has elapsed, there is a problem that the CPM cannot be improved.

In view of the above-mentioned conventional problems, it is an object of the present invention to provide an image reading apparatus capable of improving productivity without increasing the capacity of a power source.

[0007]

In order to achieve the above-mentioned object, a first means is an image reading device for reading a document conveyed by an automatic document feeder by a scanner, in the case where the scanner reads a previous document. In addition, the automatic document feeder is provided with control means for controlling the scanner to start moving toward the home position after the conveyance of the next document is started.

According to a second means, when the control means of the first means reads a document conveyed by the automatic document feeder and when a document placed on the contact glass is read, the scanner is at the home position. The control is performed such that the timing of starting the movement in the direction of is different.

[0009]

In the first means, according to the above-mentioned structure, when the original document conveyed by the automatic original document feeder is read by the scanner, the automatic original document feeder starts to convey the next original document when the scanner reads the previous original document. After that, since the scanner starts moving toward the home position, it is possible to shorten the time for replacing the originals, and thus improve the productivity without increasing the capacity of the power supply.

In the second means, the timing at which the scanner starts moving toward the home position when reading the original placed on the contact glass is different, so that the production is performed even when the automatic original feeding device is not used. Sex does not deteriorate.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are block diagrams showing a control unit of a digital copying machine which is an embodiment of an image reading apparatus according to the present invention, and FIGS. 3 and 4 are digital copying using the control unit of FIGS. 1 and 2. 5 and 6 are side views showing the overall structure of the digital copying machine, FIG. 7 is a plan view showing the detailed structure of the writing section of the digital copying machine, and FIG. 8 is a drawing. 7 is a side view showing the writing unit of FIG. 7, FIG. 9 is a block diagram showing the image scanner unit in detail, FIG. 10 is a block diagram showing the detailed configuration of the image process unit of FIG. 9, and FIG. 11 is of the image process unit of FIG. Explanatory diagram showing the data depth switching operation,
12 is a block diagram showing a memory system using the image processing unit of FIG. 9, FIG. 13 is an explanatory diagram showing the operation of a general memory system, and FIG. 14 is an explanatory diagram showing the operation of the memory system of FIG. 15 is a block diagram showing another memory system, FIG. 16 is a block diagram showing a detailed configuration of the memory unit of FIG. 15, FIG. 17 is an explanatory diagram showing processing data of the memory unit of FIG. 16, and FIG.
19 is a block diagram showing a modification of the memory system of FIG.
15 is a block diagram showing another modification of the memory system of FIG. 15, FIG. 20 is a block diagram showing another modification of the memory system of FIG. 19, and FIGS. 21 and 22 are ADFs of this embodiment.
FIG. 2 is a flowchart for explaining the operation in the mode.
3 is a timing chart showing the transport timing of the ADF and the scanning timing of the scanner in FIGS. 21 and 22.

1 and 2, this control unit has a CPU 601 for controlling sequence-related control and a main CPU 602 for controlling operational-related control. These CPUs 601 and 602 are as shown in FIGS. 3 and 4. It is mounted on the main control board 700. A CPU 601 that performs sequence-related control sets and outputs conditions relating to paper transport timing and image formation. As shown in FIG. 2, a paper size sensor 603 and sensors related to paper transport such as paper discharge detection and resist detection. 603a, a duplex unit 604, a high-voltage power supply unit 605, a driver 606 such as a relay, a solenoid, a motor, a laser beam scanner unit 608, etc. are connected. The laser beam scanner unit 608 is connected to the image control circuit 609, and the image control circuit 609 is shown in FIGS.
The circuit is configured as shown in FIGS. 10 and 12.

The paper size sensor 603 detects the size and orientation of the transfer paper loaded in the paper feed cassette, and the sensors 6
In addition to paper discharge detection and resist, 03a detects the presence or absence of supplies such as oil end and toner end, and mechanical abnormalities such as door open and fuse blown. Duplex unit 6
Reference numeral 04 has a motor for aligning the width of the paper and a side fence home position sensor, a paper feed clutch, a solenoid for changing the transport path, a paper presence / absence detection sensor, and a sensor for transporting the paper.

The high-voltage power supply unit 605 applies high-voltage power to the charging charger 41, the transfer charger 44, the separation charger 45, and the bias electrodes of the developing devices 42a and 42b shown in FIG. Is applied. The driver 606 includes a paper feed clutch, a registration clutch, a counter, a motor, a toner replenishing solenoid, a power relay, a fixing heater, and the like. The sorter unit (III) 607 has a CPU 6
01 is connected via a serial interface, and the paper is conveyed at a predetermined timing by a control signal from the CPU 601 and discharged to each bin.

As the analog signal input to the CPU 601, the detection signal of the photosensor 50 for detecting the fixing temperature and the density as shown in FIG. 6 and the monitor current and the reference voltage of the laser diode 20 as shown in FIG. 7 are input. To do. The fixing temperature is detected by the thermistor of the fixing mechanism (rollers 64, 65), and the heater is on / off controlled or phase controlled so as to be constant. Photosensor 50 for density detection
The detection signal is detected by reading a pattern formed on the photoconductor 40 with a phototransistor at a predetermined timing, the toner supply clutch is turned on and off, and the toner end is detected. The monitor current of the laser diode 20 is a reference voltage (for example, 3 m).
W) is controlled to match.

Next, the main CPU 602 which controls the operations will be described.
U602 has multiple serial ports and calendar IC61
0 is also controlled, and as shown in FIGS. 9 to 12, the quantization parameter is changed for each document according to the document size and the scaling factor. In addition to the CPU 601, the plurality of serial ports include an operation unit 611 and a scanner control circuit 612.
, Application unit 613, and editor unit 6
14 etc. are connected.

The operation unit 611 has a key input device for the operator and a display for displaying the status of the copying machine, and notifies the main CPU 602 of the key input information by serial communication. The main CPU 602 determines whether the indicator of the operation unit unit 611 is on or off based on this key input information, and notifies the operation unit unit 611 of a display command by serial communication. The operation unit 611 turns on or off the display according to this display command. Scanner control circuit 61
2 is a main CPU for serially communicating information related to drive control of the scanner servo motor, image processing, and image reading.
602, ADF (II) and main CPU 60
Interface processing between the two.

The application unit 613 performs interface processing between an external device such as a facsimile or an external printer and the main CPU 602, and exchanges predetermined information. The editor unit 614 transmits image editing data such as masking, trimming, and image software input by the operator to the main CPU 602 by serial communication.
The calendar IC 610 stores the current date and time and informs the main CPU 602 at any time. Therefore, the calendar IC 610 displays the current time on the display of the operation unit 611 and controls the on-time and off-time of the copying machine with a timer. You can

The gate array 615 is the main CPU 60.
Image data is selectively output from the scanner control circuit 612 to the image control circuit 609, from the scanner control circuit 612 to the application unit 613, or from the application unit 613 to the image control circuit 609 in response to the select signal from 2. When output from the scanner control circuit 612 to the image control circuit 609, 8-bit image data from the scanner is transmitted in synchronization with the synchronization signal PMSYNC from the laser beam scanner unit 608. When output from the scanner control circuit 612 to the application unit 613, a 1-bit (binary) signal from the scanner is output, and when output from the application unit 613 to the image control circuit 609, 1-bit (binary) signal is output. The signal is transmitted in synchronization with the synchronization signal PMSYNC.

Next, the details of the digital copying machine to which the image reading apparatus of this embodiment is applied will be described with reference to FIGS. 5 and 6, the digital copying machine is
Copier body (I) and automatic document feeder (ADF) (I
I), a sorter (III) and a double-sided reversing unit (IV). The copying machine main body (I) includes a scanner section, a writing section, a photoconductor section,
The image forming apparatus includes a developing unit and a paper feeding unit, which will be described in detail below.

The scanner unit is equipped with a reflecting mirror 1, a fluorescent lamp 3 as a light source, and a first mirror 2, and a first scanner which moves in a sub-scanning direction at a constant speed, a second mirror 4 and a third mirror. The second scanner 5 is attached and moves in the sub-scanning direction at a speed half that of the first scanner. A document (not shown) on the contact glass 9 is optically scanned by the first scanner and the second scanner, and the reflected light thereof is transmitted through the color filter 6 and the lens 7 to the light receiving surface of the one-dimensional solid-state imaging device 8. Is imaged.

A CCD image sensor is generally used as the solid-state image pickup device 8. Since the image signal read by the solid-state image sensor 8 is analog, it is A / D converted and binarized and multivalued by the processing circuits shown in FIGS. 1 to 4, 9, 10, and 12. Gradation processing, scaling processing,
Various processes such as editing are performed. In order to obtain a color signal, a color filter 6 is arranged so that it can be freely moved in and out of the optical path, and this color filter 6 is also moved in and out of the optical path in accordance with the scanning of an original to perform various types of copying such as multiple transfer and double-sided copying. Is done.

The image information after the image processing is shown in FIGS.
By the raster scanning of the laser light of the writing unit as shown in detail in FIG. 1, writing is performed on the photoconductor 40 in the form of a set of light spots. The laser light emitted from the semiconductor laser 20 is shaped into a parallel light flux by the collimator lens 21, passes through the aperture 32, is shaped into a uniform light flux, and is then compressed in the sub-scanning direction by the first cylinder lens 22. The light enters the reflecting surface of the polygon mirror 24 through the dustproof glass 23.

The polygon mirror 24 is formed in an accurate polygon and is rotated by a polygon motor 25 in a predetermined direction at a constant speed. The rotation speed is determined by the rotation speed of the photoconductor 40, the writing density, and the number of faces of the polygon mirror 24. The laser light incident on the reflecting surface of the polygon mirror 24 is deflected at a constant angular velocity, and then corrected by the f-θ lenses 26a and 26b so that the photoconductor 40 is scanned at a constant velocity. The f-θ lenses 26a and 26b
Also has a trouble correction function.

The laser light corrected by the f-θ lenses 26a and 26b is guided outside the image area by the synchronization detection mirror 29 to the synchronization detection light input section 30 and is guided to the sensor by the optical fiber. Then, after a predetermined time from the cue signal in the main scanning direction synchronized with this detection signal, image data for one line is output and guided to the photoconductor 40 side by the mirror 27. Hereinafter, by repeating this operation, an electrostatic latent image of one image is formed on the photoconductor 40.

A photoconductor layer is formed on the peripheral surface of the photoconductor 40. An organic photoconductor (OPC) is used as a photoconductor layer having sensitivity to a semiconductor laser having a wavelength of 780 nm.
Although α-Si and Se-Te are known, an organic photoconductor (OPC) is used in this embodiment. Here, when writing with the semiconductor laser 20, two types are known: a negative / positive process of irradiating the image portion with light and a positive / positive process of irradiating the background portion with light. Writing is done by a positive process.

In FIGS. 5 and 6, the charging charger 41 uses a scorotron system having a grid on the side of the photoconductor 40, uniformly charges the surface of the photoconductor 40 in a negative (-) state, and laser light is applied to the image forming area. To reduce the potential of the area. Therefore, the potential of the background area of the photoconductor 40 is −750 to −800 V, and the potential of the image area is about −500 V, so that an electrostatic latent image is formed on the photoconductor 4.
It is formed on the surface of zero.

The developing units 42a and 42b are connected to the developing roller.
A bias voltage of 500 to -600V is applied, and (-)
The charged toner is attached to the image area of the photoconductor 40 to visualize the electrostatic latent image. The developing unit of the present embodiment includes two main developing devices 42a and sub-developing devices 42b.
The toner replenishing device 43a corresponding to 2a is filled with black toner, and the toner replenishing device 43b corresponding to the sub-developing device 42b is filled with color toner, whereby selective development can be performed.

The transfer sheet is conveyed to the position of the transfer charger 44 in synchronism with the toner image on the photoconductor 40, and is transferred to the developing device 4.
The toner images visualized by 2a and 42b are transferred to the transfer paper by the transfer charger 44 charging the back surface of the transfer paper to (+). The transfer paper on which the toner image has been transferred is subjected to AC charge removal by the separation charger 45, and the photosensitive member 4
Separated from zero. The toner remaining on the photoconductor 40 is removed by the cleaning blade 47 and collected in the tank 48. The residual charge on the photoconductor 40 is removed by the charge removal lamp 49 irradiating the photoconductor 40.

A photo sensor 5 for detecting the reflection density on the photoconductor 40 is provided downstream of the developing units 42a and 42b.
0 is provided, and the photosensor 50 reads the density of a pattern such as black or halftone dots formed by the writing unit and developed and the density other than this pattern, and detects the density of the toner image to detect light The toner replenishment signal is output to or the toner remaining amount shortage signal is output to.

The paper feeding unit is composed of a plurality of cassettes 60a, 60.
b, 60c, and is configured to perform double-sided copying and sheet re-feeding by guiding the sheet once transferred to the transfer position via the sheet re-feeding loop 72. When the copy start button is pressed after one of the cassettes 60a, 60b, 60c is selected, the corresponding paper feed roller 61a,
One of the rollers 61b and 61c rotates, and the transfer sheet is conveyed until its leading end abuts the registration roller 62. Then, the registration roller 62 starts rotating so that the toner image on the photoconductor 40 and the transfer sheet are synchronized, and the above-described transfer is performed.

The transfer sheet separated from the photoconductor 40 is sucked and conveyed by the separation conveying section 63, and the fixing roller 6
The toner image is fixed by 4, 65. Then, this transfer sheet is guided to the sheet discharge port on the sorter (III) side in the case of a normal single-sided copy, and in the case of multiple copy, the copy claws are not changed by the switching claws 67, 68, 69. It returns to the position of the registration roller 62 via the lower re-feeding loop 72. In the case of double-sided copying, the copy surface is reversed by the copying machine body (I) or the double-sided reversing unit (IV). In the former case, the switching claws 68, 69, 71
Is guided to the tray 70 below the re-feeding loop 72 and is returned in the opposite direction by reversing the roller 71.
Switching to the sheet re-feeding loop 72, the sheet is inverted and returned to the position of the registration roller 62.

The ADF (II) is configured to automatically convey the originals one by one onto the contact glass 9 and eject the originals from the contact glass 9 after reading. Specifically, the document stack placed on the document feed tray 100 is aligned in the width direction by the side guides 101, and is fed by the feed rollers 104.
Are separated and taken in by each. Separation roller 1
The original passing through 04-1 has its original size detected by registration detection, original width detection, and original length detection by a pulse generator, and is conveyed and positioned on the contact glass 9 by rotation of the conveyor belt 102, and reading is completed. Then, the conveyance belt 102 is driven to discharge the sheet onto the sheet discharge tray 103. Note that the size of the document can be counted by counting the position of the side guide 101 and the document feeding time. Then, the timings of carrying and discharging the original document are controlled by driving the carrying motor and the paper discharging motor 701 shown in FIG.

The sorter (III) is configured to selectively discharge the transfer paper discharged from the copying machine main body (I), for example, in page order, page by page, or to preset bins 111a to 111x. .. In this case, the transfer paper is conveyed by a plurality of rollers that are rotated by the motor 110, and the bin 11 is moved by the switching claws arranged near the inlet of each bin.
1a to 111x.

The double-sided reversing unit (IV) is used when reversing the front and back sides of a plurality of transfer papers for double-sided copying.
In this case, the transfer paper inside the copying machine main body (I) is the discharge roller 6
It is guided downward by 6 and is guided to the double-sided reversing unit (IV) by the next switching claw 68. Then, the discharge roller 1
The sheets 20 are stacked on the tray 123, and are vertically and horizontally aligned by the feed roller 121 and the side surface alignment guide 122. The transfer sheets accumulated on the tray 123 are returned to the inside of the copying machine main body (I) by the re-feed roller 124, and are directly guided to the re-feed loop 72 by the switching claw 69.

In FIG. 9, the analog image signal read by the CCD image sensor 8 is the signal processing circuit 4 in the image preprocessors (IPP) 451 to 453.
Amplification and light amount correction are performed at 51, and the digital multilevel signal is converted at the A / D converter 452. The shading correction circuit 453 corrects the unevenness of the light amount and the error of the CCD image sensor 8 to the digital multi-level signal, and the image process unit (IPU) 5 as shown in detail in FIG.
Is output to 00.

In the IPU 500 shown in FIG. 10, this digital multilevel signal is emphasized in the high frequency range by the MTF correction circuit 501, scaled by the scaling circuit 502, and then the γ conversion circuit 503.
Is converted so that the gradation input / output characteristics are optimized,
Then, this signal is the switch SW of the data depth switching mechanism.
1 selectively converts into four quantization levels.
The 4-bit conversion circuit 504 converts the 8-bit signal as shown in FIG. 11A into 4-bit data as shown in FIG. 11B, and the binarization circuit 505 is shown in FIG. 11A. Such an 8-bit signal is converted into 2-bit data as shown in FIG. 11C, and the dither circuit 506 is converted into the dither circuit 506 shown in FIG.
The area gradation is generated by 1 bit from the signal of 8 bits as shown in FIG. The switch SW2 selects the output signal of the binarization circuit 505 or the dither circuit 506, and outputs it via the switch SW1.

Returning to FIG. 9, the scanner control circuit 460 follows the instruction from the printer control circuit and the fluorescent lamp ballast 45.
8. Controls the timing control circuit 459, the scaling circuit 502 of the IPU 500, and the scanner drive motor (M) 465. The fluorescent light ballast 458 controls on / off and the amount of light of the fluorescent light 3 according to an instruction from the scanner control circuit 460. A rotary encoder 466 is connected to the drive shaft of the scanner drive motor 465, and the position sensor 462 is used to detect the reference position (home position) of the sub-scanning mechanism. The scaling circuit 502 electrically scales according to the magnification data in the main scanning direction set by the scanner control circuit 460.

The timing control circuit 459 outputs various signals in accordance with instructions from the scanner control circuit 460, and when reading is started, for example, a transfer for transferring one line of data to the CCD image sensor 8 to the shift register. A signal and a shift clock pulse for outputting the data of the shift register bit by bit are output. The timing control circuit 459 also outputs a pixel clock pulse CLK, a main scanning synchronization pulse LSYNC, a main scanning effective period signal LGATE and a sub-scanning effective period signal FGATE to the control unit of the image reproduction system.

Here, the pixel clock pulse CLK is C
The signal is almost the same as the shift clock pulse applied to the CD image sensor 8. Also, the main scanning synchronization pulse L
SYNC is almost the same signal as the main scanning synchronization signal PMSYNC output from the beam sensor of the image writing unit, but is output in synchronization with the pixel clock pulse CLK.
The main scanning effective period signal LGATE is output data DATA0.
~ DATA7 goes high at the timing when it is considered to be valid data. The CCD image sensor 8
Is configured to output, for example, valid data of 4800 bits per line.

When the scanner control circuit 460 receives a reading start instruction from the printer control circuit, it turns on the fluorescent lamp 3, starts driving the scanner drive motor 465, controls the timing control circuit 459, and controls the CCD image sensor 8.
To start reading. Further, the sub-scanning effective period signal FGATE is set to the high level, and is set to the low level when the time required to scan the maximum reading length in the sub-scanning direction (for example, the dimension in the A size longitudinal direction) elapses.

In the memory system shown in FIG. 12, the signals processed by the above-mentioned IPPs 451 to 453 are selected by the multiplexer 511 and then the above-mentioned IPU 50 is selected.
0, processed by 0, selected by the multiplexer 512, and output to the printer unit (PR). Also, IPU5
The signal before being processed by 00, the processed signal, or the signal from the outside such as a facsimile is transmitted to the multiplexer 51.
3 can be stored in the memory (MEM) 514 via
The signal stored in the memory 514 is sent to the multiplexer 51.
It is also possible to output to the printer unit via 2 or output again to the IPU 500 via the multiplexer 511 for processing.

That is, in a digital copying machine using a memory, as shown in FIG. 13, a signal processed by the IPU 500 is usually output directly to the printer unit or the memory 51.
4 and then output to the printer unit to copy the second and subsequent sheets. In the circuit example shown in FIG.
As shown in FIG. 4, it is possible to change a parameter and make a plurality of copies with one reading. In the case of simple data such as 1-bit data, the signal processed by the IPU 500 can be fetched in the memory 514 and the printer unit can be switched to the binary data mode for copying.

Further, as shown in FIGS. 15 to 17, a compressor (COMP) is provided before and after the memory unit 520.
515 and multiplexer 516 and expander (EX
P) 517 and multiplexer 518 may be provided and configured to store actual or compressed data in memory unit 520. In this case, the compressor 515 needs to operate according to the speed of the scanner, and the decompressor 517 needs to operate according to the speed of the printer.
As shown in FIG. 7, three types of image data of 8 bits, 4 bits, and 1 bit, and data width converters 522 and 523 for processing code data that is compressed data are provided before and after the memory block 521, respectively. .. The direct memory access controller (DMAC
1, DMAC2) 524 and 525 are configured to write and read data to and from a predetermined address of the memory according to the number of data and the data width packed and unpacked by the data width converters 522 and 523, respectively. ..

Here, the speed of the image data from the scanner or the image data to the printer is 8 bits,
It is constant regardless of 4 bits or 1 bit, and the period of 1 pixel is fixed in the device. The input data width converter 522 converts each data of eight data lines from the most significant bit MSB to 1-bit data, 4-bit data,
The memory block 52 is packed and packed according to 8 bits.
Output to 1. The output data width converter 523 unpacks the packed data into the original data. Therefore, the memory block 521 can be effectively used according to the data depth.

In the memory system 530 shown in FIG. 18,
A pixel process unit (PPU) 532 is provided outside the memory unit 531 instead of the compressor 515 and the decompressor 517 shown in FIG. This PPU 532 is a logical operation (for example, AN
D, OR, EOR, NOT) and multiplexer 5
The data is output to the printer unit via 34 or stored in the memory unit 531 via the multiplexer 533. In this memory system 530, overlay data can be stored in the memory unit 531 in advance, and the PPU 532 can superimpose the overlay data and the scanner data.

The memory system 540 shown in FIG. 19 is configured to store image data from an external storage device. Image data to floppy disk (F
D) When the image data from the external storage device is stored in the I / F 541 and the floppy disk controller (FD) under the control of the file controller 548.
C) Floppy disk drive device (F
DD) 543 is output. The memory system 540 includes a hard disk controller (HDC) 5
46 and a hard disk drive (HDD) 547 are provided, and image data from an external storage device can be stored in the hard disk. It should be noted that the hard disk can store format data and overlay data that are frequently used and can be read out as needed. Also,
Reference numeral 545 is a line drawer.

The memory system 550 shown in FIG. 20 is configured to cope with the case where the processing speeds of compression and decompression are not in time. The image data at the time of scanning by the scanner is stored in the memory unit 552, compressed by the compressor 551 and stored in another area of the memory unit 552, and the compressed data is expanded by the expander 553 and passed through the multiplexer 554. Output to the printer section. All data on one page is in memory unit 55
If the processing of the compressor 551 and the decompressor 553 ends normally in time before being stored in 2, the compressed data is stored in the memory unit 552 and the raw data is erased. On the other hand, when the error detection circuit 556 detects an error signal from the compressor 551 or the decompressor 553, the compressed data is immediately canceled and the raw data is selected.

The memory management unit (MMU) 555 is
Two input data are stored in the memory unit 552,
It controls so that one output data is read from the memory unit 552. Therefore, according to the memory system 550, the compression and decompression processes are inspected.
It is possible to realize high speed and certainty of data.
The area of the memory unit 552 can be effectively used. Instead of controlling the writing and reading of data by the memory management unit 555, two memory units for raw data and compressed data may be provided. In addition, the memory system 550 is most suitable for applications in which the number of stored pages and the printer speed must be compatible, such as in the case of storing a plurality of pages and outputting them to the printer in real time, such as electronic sorting. ..

The operation in the ADF mode of the above embodiment will be described with reference to FIGS. 21 to 23. When the scanner returns to the home position and is ready for copying, the process proceeds from step S1 to step S2, and when the print button is pressed, the process proceeds from step S2 to step S3.
When the document is set on the ADF (II), the process proceeds from step S3 to step S4, and the current document is controlled to be fed into the contact glass 9.

In the following step S5, the feed-in timing of ADF (II), which is the timing of starting the conveyance of the next document, is calculated, and in step S6, the return timing is calculated to return the scanner to the home position after the reading is completed. Here, the feed-in timing is the return timing of the scanner in the conventional example as shown in FIG. 23, and corresponds to the scanning distance A in the forward direction.
The scanning distance A is the length of the transfer paper when the copy magnification is equal to or less than 100% or is reduced, and is the length / magnification of the transfer paper when the copy magnification is 101% or more. is there. That is, the feed-in timing is the position of the A / B pulse from the movement start of the scanner when the scanner scans the distance B by one pulse of the encoder.
On the other hand, the return timing of the scanner is a timing delayed by the delay time z from the feed-in timing of the next document. That is, when the magnification is 100%,
When the time for scanning one pulse of the encoder is C, the return timing of the scanner is (feed-in timing + z / C) pulses.

In the subsequent step S7, it is determined whether or not the original document is set at a predetermined reading position on the contact glass 9, and if it is set, the scanner is moved in the forward direction (step S8), and the above-mentioned operation is performed. Image reading processing is performed (step S9). Then, it is determined whether or not it is the feed-in timing of the next document (step S10), and if it is that timing, the process proceeds to step S11. When the original document of this time is read again in step S11, the process branches to step S12, the scanner is moved in the return direction, and the scanner returns to the home position (step S11).
13) The scanner is stopped (step S14), and when the movement start timing of the scanner in the forward direction comes (step S15), the process returns to step S8 to read the original document again.

On the other hand, in the case of the last copy in which the original is not read again in step S11, step S11
When the document is set in the ADF (II) (step S17), the process is controlled so that the current document is fed out and the next document is fed in on the contact glass 9 (step S18). ). Next, it is judged whether or not it is the return timing of the scanner, and if it is that timing, steps S18 to S19
When the scanner is moved in the return direction to return to the home position (step S20), the scanner is stopped (step S21), and the process returns to step S7.

In step S16, ADF (II)
If the next original is not set in, the scanner is immediately moved in the return direction (step S22), and when the scanner returns to the home position (step S23),
The scanner is stopped (step S24).

Therefore, according to the above embodiment, the ADF
When the originals are conveyed and read one by one according to (II), the feed-in of the next original is started first, and then the scanner is moved in the return direction, so that the productivity of copying can be improved. In addition, since the feed-in of the next document and the start of the scanner return do not overlap, a large capacity power supply is not required.

When the ADF mode is not set, that is, when the document is manually placed, the scanner is returned at the feed-in timing in the ADF mode.
CPM does not deteriorate.

[0057]

As described above, according to the first aspect of the present invention, in the image reading device for reading the document conveyed by the automatic document feeding device by the scanner, the automatic reading is performed when the scanner reads the previous document. Since the document feeding device is provided with the control means for controlling the scanner to start moving toward the home position after the next document is started to be conveyed, the document replacement time can be shortened. The productivity can be improved without increasing the capacity of the power supply.

According to a second aspect of the invention, the scanner is used when the control means according to the first aspect reads an original document conveyed by an automatic original document feeder and when an original document placed on a contact glass is read. Since the control is performed such that the timing of starting the movement toward the home position is different, the productivity does not deteriorate even when the automatic document feeder is not used.

[Procedure amendment]

[Submission date] October 26, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a block diagram showing a part of a control unit of a digital copying machine which is an embodiment of an image reading apparatus according to the present invention.

FIG. 2 is a block diagram showing another part of the control unit of the digital copying machine which is an embodiment of the image reading apparatus according to the present invention.

FIG. 3 is a block diagram showing a partial circuit configuration of a digital copying machine in which the control unit shown in FIGS. 1 and 2 is used.

FIG. 4 is a block diagram showing a circuit configuration of another portion of a digital copying machine in which the control unit shown in FIGS. 1 and 2 is used.

FIG. 5 is a side view showing a part of the overall configuration of the digital copying machine.

FIG. 6 is a side view showing another part of the overall configuration of the digital copying machine.

7 is a plan view showing a detailed configuration of a writing unit of FIG.

8 is a side view showing the writing unit of FIG. 7. FIG.

FIG. 9 is a block diagram showing in detail an image scanner unit.

10 is a block diagram showing a detailed configuration of the image process unit of FIG.

11 is an explanatory diagram showing a data depth switching operation of the image process unit of FIG.

12 is a block diagram showing a memory system using the image processing unit of FIG.

FIG. 13 is an explanatory diagram showing an operation of a general memory system.

FIG. 14 is an explanatory diagram showing an operation of the memory system of FIG.

FIG. 15 is a block diagram showing another memory system.

16 is a block diagram showing a detailed configuration of the memory unit of FIG.

17 is an explanatory diagram showing processing data of the memory unit of FIG.

FIG. 18 is a block diagram showing a modification of the memory system of FIG.

FIG. 19 is a block diagram showing another modification of the memory system of FIG.

20 is a block diagram showing another modification of the memory system of FIG.

FIG. 21 is a part of a flowchart for explaining the operation in the ADF mode of this embodiment.

FIG. 22 is another part of the flowchart for explaining the operation in the ADF mode of this embodiment.

FIG. 23 is a timing chart showing the transport timing of the ADF and the scanning timing of the scanner in the operations of FIGS. 21 and 22.

FIG. 24 is a timing chart showing ADF transport timing and scanner scanning timing in a conventional example.

[Explanation of Codes] II ADF (Automatic Document Feeder) 465 Scanner Motor 601 CPU (Central Processing Unit) 701 ADF Conveying and Discharging Motor

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 8]

FIG. 11

[Figure 1]

[Fig. 12]

[Fig. 13]

[Fig. 2]

FIG. 14

FIG. 17

[Figure 3]

[Figure 7]

FIG. 18

[Figure 4]

FIG. 23

[Figure 5]

[Figure 6]

[Figure 10]

[Figure 9]

FIG. 24

FIG. 15

FIG. 16

FIG. 19

FIG. 20

FIG. 21

FIG. 22

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03G 15/04 114 9122-2H

Claims (2)

[Claims] 1. An image reading apparatus for reading a document conveyed by an automatic document feeder by a scanner, wherein the automatic document feeder starts conveying the next document when the scanner reads the previous document, An image reading apparatus comprising control means for controlling the scanner to start moving toward the home position. 2. The control means starts moving the scanner toward a home position when reading a document conveyed by an automatic document feeder and when reading a document placed on a contact glass. The image reading apparatus according to claim 1, wherein the timing is controlled so as to be different.