JP2002027200A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader having interfaces that maximally enhances its throughput while decreasing frequency of occurrence of image read intermittent operations. SOLUTION: A step motor moves a carrier to read an image or moves the original in the subscanning direction. In the case of selecting a SCSI board 31, the moving speed (read rate) of the carrier or the original in the subscanning direction by the step motor is selected to be 100 mm/s. In the case of selecting an ISIC board 30, an image of a read original is read by using a prescribed pulse number of clock pulses for a read period to drive the step motor for each image line.

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, and more particularly, to an image reading apparatus having a plurality of interfaces, and more particularly to an image scanner having an interface with a host device, a digital copying machine, a digital facsimile machine, and the like. The present invention relates to a technique applicable to an image reading apparatus such as a unit.

[0002]

2. Description of the Related Art In an image reading apparatus that transfers image data to an external device while reading an image, if the image data transfer speed to the external device is lower than the reading speed of an original, the image data is read into the image reading device. By providing a memory for temporarily storing image data, data is transferred to an external device at a data transfer speed. However, if the difference between the speed at which image data is stored in the image storage memory and the data transfer speed to an external device is large, or if the reading density is high and the image data is large, the memory will A full case occurs. In this case, the reading operation is stopped by performing the through-down control of the pulse motor that drives the document reading unit, and when the memory is in the empty state by transferring data to an external device during this time, the pulse motor is controlled by the through-up control. A series of image reading is executed by an intermittent operation of starting and restarting reading.

However, it is known that, when the pulse motor is through-up or down during the intermittent reading operation, the read image is generally deteriorated due to the vibration caused by the start and stop of the motor. For example, in an image reading device such as a scanner, the difference between the reading speed and the data transfer speed to an external device, or when the reading density is high and the image data is large, several times to several times in one reading operation. Ten intermittent operations occur.

In order to prevent the intermittent operation from occurring, it is possible to make the above-mentioned image memory capacity larger than the document image data capacity or to make the data transfer speed to the external device higher than the image reading speed. is there. However, it is difficult to mount a large-capacity image memory that can handle all original images, and it is difficult to increase the data transfer speed to external devices faster than the image reading speed depending on the interface connected. It is difficult because it is decided.

Generally, in order to reduce the frequency of the above-described intermittent operation, the reading speed in the sub-scanning direction is reduced depending on the reading mode of the image reading apparatus during reading at a high resolution. It has been practiced to reduce the frequency of occurrence of operations to prevent image deterioration. In such a case, it is most effective to set an appropriate reading speed equal to the data transfer speed to the external device in order to prevent the occurrence of the intermittent operation while exerting the throughput of the image reading device.

In an image reading apparatus having an interface with a host device, an interface for exchanging data with an external device is indispensable, and the interface has been diversified in recent years. SCSI for parallel I / F, USB, IEEE13 for serial I / F
94, an interface represented by a network or the like. To support various interfaces, as an image reading device, either standard or optional
Some models are equipped with multiple interfaces,
Models that can be connected to a plurality of host devices at the same time are increasing.

Until now, in this type of image reading apparatus, the most general-purpose SCS has been used as an interface with an external device.
In most cases, I (Small Computer System Interface) is implemented as a standard. For example, SCSI2
The standards include asynchronous transfer and synchronous transfer.
It has the following maximum transfer rates. -Asynchronous transfer: 5M (Byte / s)-Synchronous transfer: 10M (Byte / s)

As an interface with an external device, S
In a device having CSI and an IEEE 1394 interface, the maximum transfer speed of the currently standardized IEEE 1394 interface is 50M (Byte / s).
Therefore, in an environment in which data transfer at the maximum transfer speed of each interface is possible, the read operation when the SCSI2 synchronous transfer is used is not compatible with the IE.
In the reading operation using the EE1394 interface, the frequency of the intermittent operation can be the same even when reading is performed at a reading speed five times faster.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and in an image reading apparatus having a plurality of interfaces, (1) the reading speed in the sub-scanning direction is variable; By setting the optimum speed according to the selected interface, the frequency of the intermittent operation of image reading is reduced, and the throughput of the device is maximized. (2) In the above (1), the selection is made. (3) In the above (1), the reading speed can be changed by the user's selection, so that the maximum data transfer speed of each interface cannot be exhibited. Even when an external device is connected, by enabling the user to set the optimal reading speed, To maximize the throughput of the device while reducing the frequency of the intermittent operation of reading, (4) In the above (2), one interface can be selected by automatically detecting the connection type of the interface controller. It is intended to make it possible.

[0010]

According to a first aspect of the present invention, there is provided a document reading means for reading an image of a document to be read in a desired reading cycle line by line, and moving the document reading means or the read document in the sub-scanning direction. A stepping motor, reading control means for controlling reading of the image with a predetermined number of clock pulses for driving the stepping motor as the desired reading cycle, and storing image data read by the document reading means. An image memory, a memory controller for controlling the image memory, and a plurality of interfaces for controlling the output of the image data to an external device, wherein the step motor is configured to operate according to the selected capability of the interface. The document reading means or the moving speed of the read document in the sub-scanning direction Is obtained is characterized in that a further possible.

According to a second aspect of the present invention, in the first aspect of the present invention, there is provided an interface selecting means for selecting one of the interfaces, and the original reading means by the step motor according to the capability of the selected interface. Alternatively, the moving speed of the read document in the sub-scanning direction can be changed.

According to a third aspect of the present invention, in the first aspect of the invention, there is provided a reading speed selecting means for selecting the original reading means by the step motor or a moving speed of the read original in the sub-scanning direction. Things.

According to a fourth aspect of the present invention, in the second aspect of the present invention, there is provided an interface detecting means for automatically detecting a selected interface, and the original is read by the step motor in accordance with the capability of the automatically detected interface. Means or a moving speed of the read document in the sub-scanning direction can be changed.

[0014]

FIG. 1 is an overall configuration diagram for explaining an example of an image reading apparatus to which the present invention is applied. A document placed on a platen glass 1 includes a first mirror 2 and a first mirror 2. Irradiated by the integrally formed illumination lamp 3, the reflected light is applied to the first mirror 2 and the second mirror 4, which is integrally formed.
Scanning is performed by the third mirror 5. Thereafter, the reflected light is converged by the lens 16 and irradiated on the CCD 6 to be photoelectrically converted. First mirror 2, illumination lamp 3, and second mirror 4,
The third mirror 5 is configured to be movable in the direction A by using the traveling body motor 7 as a drive source. The above-described operation is a mode in which an image is read by moving the traveling body, and is referred to as a Book mode.

In the example shown in FIG. 1, the originals stacked on the original tray 8 are picked up by a pickup roller 9, a pair of registration rollers 10, a transport drum 11, and a transport roller 12.
After passing through the reading position B, the sheet is fed to the conveying roller pair 13 and the sheet discharging roller pair 14 and is discharged onto the sheet discharging tray 15. When the document passes through the reading position B, the original is illuminated by the illumination lamp 3 moving near the reading position B, and the reflected light thereof is reflected by the first mirror 2 and the second mirror 4 integrally formed.
Scanning is performed by the third mirror 5. Thereafter, the reflected light is converged by the lens 16 and irradiated on the CCD 6 to be photoelectrically converted. Pickup roller 9, registration roller pair 10
Is driven by a feed motor (not shown), and the transport drum 11, the transport roller 12, the transport roller pair 13, and the discharge roller pair 14 are driven by a transport motor (not shown). The operation described above is a mode in which an image is read by moving a document to be read, and is called an ADF mode.

FIG. 2 is an overall block diagram for explaining an example of an image reading apparatus to which the present invention is applied. SCSI and IEEE1394 are used as external device interfaces.
Is an example of a configuration of an image reading apparatus equipped with (an arbitrary number of devices and interfaces having external device interfaces other than those described above). The reflected light of the document that has entered the CCD 6 on the SBU 26 is converted into an analog signal having a voltage value according to the light intensity in the CCD 6, and the analog signal is divided into odd bits and even bits and output. The analog image signal is input to an A / D converter after a dark potential portion is removed by an analog processing circuit (not shown) on the SBU 26, an odd bit and an even bit are combined, and the gain is adjusted to a predetermined amplitude. And converted into a digital signal. The digitized image signal is SC
After the shading correction, the gamma correction, the MTF correction, and the like are performed by the NIPU 33 on the U32, the binarized data is output as a video signal together with a page synchronization signal, a line synchronization signal, and an image clock.

The video signal output from NIPU 33 is output to option IPU 29 via connector 34. The video signal output to the option IPU 29 is subjected to predetermined image processing in the option IPU 29, and is input to the SCU 32 again. The video signal input to the SCU 32 again is input to a selector (not shown). The other input of the selector is NIPU 33
Video signal output from the
The PU 29 can select whether to perform image processing or not. The video signal output from the selector is input to an image data storage unit (DRAM) and a memory control unit 35 for managing data transmission / reception control with various I / F controllers, and the image data is transferred to an image memory configured by the DRAM. The image data stored in the image memory is stored in the SCSI controller 20 or the IEEE
The data is sent to the E1394 LINK controller 19 by the DMA control method, and is transferred to an external device such as a personal computer.

The SCU 32 has a CPU 37 and a ROM 3
6, a RAM 38 is mounted, and the CPU 37
SI controller 20 or IEEE 1394 LIN
The K controller 19 is controlled to communicate with an external device such as a personal computer. Further, the CPU 37 also controls the timing of the traveling body motor 7, which is a stepping motor, the sheet feeding motor, and the transport motor. The ADU 17 has a function of relaying power supply of electrical components used in an automatic document feeder (ADF) unit. An input port connected to the CPU 37 on the SCU 32 is connected to the main body operation panel 25 via the IOB 27.

(Claim 1) FIG. 3 is a main block diagram for explaining an embodiment of an image reading apparatus according to the present invention. Hereinafter, an example will be described in which a basic reading density of 400 dpi is read at the time of connection with a plurality of interface controllers. The image reading apparatus includes a SCSI-I / F controlled by a SCSI controller 20 as an interface with an external device, and an IEEE 1394.
LINK controller 19 and IEEE1394 PHY
IEEE 1394 controlled by controller 18
−I / F. The image data transmitted from the NIPU 33 is stored in the image memory constituted by the DRAM 23 by the SIBC 22, and the image data stored in the image memory is transmitted from the SIBC 22 to the interface circuit 21. In the present embodiment, the description will be made on the assumption that data transfer between each interface controller and the interface circuit 21 is performed by DMA.

Generally, in the DMA control, a DREQ (data request) signal is actively output from a data requesting device, and a device which has requested data transmits a DACK (data acknowledge) signal when data transmission is ready. At the same time as the active output, the data is output to the data request device.
Data is taken in from the timing of the CK signal. Until the data request device finishes capturing the required amount of data,
The data transfer is completed by repeating the above control.

In the present invention, the data request device is an SCS
I controller 20 or IEEE 1394 LINK
The controller 19 and the device on which data is requested are the memory control unit 35 having the interface circuit 21. Even if the DMA control method is the same, the control timing and the data transfer rate are limited by the DMA controller built in the device to be used, and the SCSI controller is used by the same DMA controller as the data requesting device. Normally, it is not possible to control the controller 20 and the IEEE 1394 controller 19 (they can be controlled if they are designed with exactly the same control and timing in advance. In the above case, they can be controlled by the same SIBC 22 and DRAM 23). . As described above, in the present invention, the control corresponding to a plurality of interface controllers can be performed by switching the selection of the DMA controller corresponding to the interface control device selected at the time of the image reading operation in the interface circuit 21.

According to the SCSI protocol, the SCSI bus phase has four types of states: a bus free phase, an arbitration phase, a selection phase, and an information transfer phase. When the image reading apparatus of the present invention is selected on the SCSI bus through the above-described phase, by shifting to the information transfer phase, the present image reading apparatus and an external host device (not shown) are brought into a data transfer enabled state. Become. When the image reading apparatus transfers a read command from the host device in the information transfer phase, the read command data is stored in the internal FIFO of the SCSI controller 20, and at the same time, an interrupt occurs in the CPU 37 (INTSCSI signal issuance). Is S
By reading the register of the CSI controller 20, a read command from the host device is recognized. After recognizing the command, the CPU 37 causes the interface circuit 2
In step 1, a DMA controller for the SCSI controller 20 is selected, and image data transfer with the SCSI controller 20 by DMA is performed.

According to the IEEE 1394 protocol, a root node, an isochronous manager, a cycle master, and a bus manager are determined through bus initialization, tree identification, and self-identification, so that arbitration can be performed. When the image reading apparatus according to the present invention has won the arbitration after passing through the above phases, the
By acquiring the right to use the 394 bus, the image reading device and the host device enter a data transferable state. When a read command is transferred from the host device, the IEEE1394
At the same time that the read instruction data is stored in the internal FIFO of the LINK controller 19, an interrupt occurs to the CPU 37 (INT1394 signal is issued), and the CPU 37
By reading the register of the E1394 LINK controller 19, a read command from the host device is recognized. After the command recognition, the CPU 37 selects the DMA controller for the IEEE 1394 LINK controller 19 in the interface circuit 21 and the IEEE 1
Image data transfer by DMA with the 394 LINK controller 19 is performed.

For example, in the above-described configuration, when reading by the SCSI interface is selected, 100 mm / s is selected as the moving speed ((reading speed)) of the traveling body by the motor or the document in the sub-scanning direction. When reading by the IEEE 1394 interface is selected, the reading speed in the sub-scanning direction is selected to be 500 mm / s. Can be set.

FIG. 4 is a diagram showing an example of the relationship between the motor clock of the traveling body motor 7 and the reading operation timing in line units (operation in the Book mode) in the image reading apparatus according to the present invention. The read timing pulse is generated asynchronously with the motor clock pulse. FIG. 4A shows a case where the reading speed is 500 mm / s.
FIG. 4B shows a case where the reading speed is 100 mm / s. In both cases, the reading timing pulse is made effective every three clock pulses of the traveling body motor 7 and one line is read at that timing. The number of read data with respect to the moving distance of the traveling body is set to be the same.

For example, assuming that the running body advances by 0.0117 mm per one cycle of the motor clock, the reading speed is different from the following formula (500 mm / s, 10 mm).
(0 mm / s), it is possible to capture an image of 400 dpi. (Equation) 0.0117 × 3 = 0.0635 mm / LINE = 0.0635 / pixel (400 dpi) In the ADF mode, the relationship between the transport motor clock and the read operation timing in line units is obtained.

(Claim 2) FIG. 5 is a main block diagram for explaining another embodiment of the image reading apparatus according to the present invention. As a method for selecting an interface, an interface selection SW 32 is prepared and SW 42 is turned off. When the switch is ON, an “H” level voltage is output from the pull-up power supply 41 to the CPU 37, and when the SW 42 is turned ON,
The configuration is such that an “L” level voltage is output. An interface controller corresponding to the above logic is set in advance. For example, the IO port logic of the CPU 37 is "H" for SCSI-I / F, and "L" for IEEE-IO.
1394-I / F. When the IO port logic of the CPU 37 is “H”, the CPU 3 detects the interrupt signal INT 1394 from the IEEE 1394 LINK controller 19.
Prohibit with 7. Also, the IE inside the interface circuit
The EE1394 controller I / F bus is shut off. With the above control, the interface circuit 21 is prohibited from accepting requests other than the request from the SCSI controller 20. CPU
When the IO port logic of the 37 is “L”, the setting opposite to the above is performed, so that the interface circuit 21 is prohibited from accepting requests other than the request from the IEEE1394 LINK controller 19.

(Claim 3) The reading speed setting method by the user can be changed by an input operation using the key SW on the main body operation panel 28 or by transmitting a reading speed selection command from an external device.

FIG. 6 is a main block diagram for explaining another embodiment of the image reading apparatus according to the present invention. According to the second aspect of the present invention, it is necessary to manually select an interface by the interface selection SW32 which is an external interface selection unit. According to the fourth aspect of the present invention, the external interface selecting means is not required, and one I / F can be automatically selected from a plurality of I / Fs.

SCS with SCSI controller 20
An I board 31, an IEEE 1394 LINK controller 19, and an ISIC (IEEE 1394 serial interface controller) board 30 having an IEEE 1394 PHY controller 18 can be arbitrarily attached and detached. The SCSI board 31 and the ISIC board 30 are connected to the SCU 32. SCSI board 3
1. The ISIC board 30 has a signal INSTSCSI signal for detecting connection with the SCU 32, INST139.
The SCU 32 has four signals,
It is connected to pull-up power supplies 39 and 40.

SCSI board 31, ISIC board 30
Is not connected, the INST SCSI signal, INST1
394 signals become “H” level signals, and SCU32
CPU 37 recognizes that the SCSI board 31 and the ISIC board 30 are not connected. In the above case, the fact that there is no I / F to which image data can be transferred is displayed on the main body operation panel 25, and the SCSI controller 20,
The CPU 37 inhibits the interrupt signal INTSCSI signal and the INT1394 signal detection from the IEEE1394 LINK controller 19 from being detected.

When only the SCSI board 31 is connected, the INTSCSI signal becomes "L" level and the CPU
37 recognizes the connection of the SCSI board 31, and
The CPU 37 inhibits the detection of the INT1394 signal, which is an interrupt signal from the 394 LINK controller 19.
By the above control, the interface circuit 21
Acceptance of requests other than requests from the controller 20 is prohibited.

IEEE 1394 LINK controller 1
9 is connected, the INT 1394 signal becomes the “L” level, and the setting opposite to the above is performed, so that the interface circuit 21 is connected to the IEEE 1394L.
Acceptance of requests other than requests from the INK controller 19 is prohibited.

SCSI board 31, ISIC board 30
If both are connected, the IEEE1394 LIN
INT1 which is an interrupt signal from the K controller 19
394 signal or INTSCSI signal, which is an interrupt signal from the SCSI controller 20, is monitored together, and the interface that first requested an interrupt is given priority,
Interrupt requests from other interface controllers during the reading operation are prohibited.

The SCSI board 31, ISIC (IEEE
If the 1394 serial interface controller) board 30 is not configured to be detachable,
The control is the same as when the CSI board 31 and the ISIC (IEEE 1394 serial interface controller) board 30 are both connected.

[0036]

According to the first aspect of the present invention, the reading speed in the sub-scanning direction is made variable according to the selected interface, and is set to the optimum speed.
It is possible to maximize the throughput of the device while reducing the frequency of occurrence of the intermittent operation.

(2) Effects of the Second Embodiment The reading speed of an image in the sub-scanning direction can be changed by the SW.

(3) Advantageous Effects of the Third Embodiment Since the reading speed can be changed by the user's selection, even if an external device that cannot exhibit the maximum transfer speed of each interface is connected, the user can optimize the reading speed. A high reading speed can be set, and the throughput of the device can be maximized while reducing the frequency of occurrence of the intermittent operation.

(4) Effect of the Invention of Claim 4 Since the connection type of the interface controller is automatically detected, it is possible to automatically select one interface.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram for explaining an example of an image reading apparatus to which the present invention is applied.

FIG. 2 is an overall block diagram illustrating an example of an image reading apparatus to which the present invention is applied.

FIG. 3 is a main part block diagram for explaining an embodiment of the image reading apparatus according to the present invention.

FIG. 4 is a diagram showing an example of a relationship between a motor clock of a traveling body motor and a reading operation timing in line units in the image reading apparatus according to the present invention.

FIG. 5 is a main part block diagram for explaining another embodiment of the image reading apparatus according to the present invention.

FIG. 6 is a main part block diagram for explaining another embodiment of the image reading apparatus according to the present invention.

[Explanation of symbols]

Reference numeral 1: platen glass, 2: first mirror, 3: illumination lamp,
4 Second mirror, 5 Third mirror, 6 CCD, 7 Running motor, 8 Document tray, 9 Pickup roller, 10 Registration roller pair, 11 Transport drum, 12
... Conveying rollers, 13: Conveying roller pairs, 14: Discharge roller pairs, 15: Discharge tray, 16: Lens, 17: ADU,
18 ... IEEE1394PHY controller, 19 ... I
EEE1394LINK controller, 20 ... SCSI
Controller, 21 interface circuit, 22 S
IBC, 23 ... DRAM, 25 ... Main unit operation panel, 26
... SBU, 27 ... IOB, 28 ... Main body operation panel, 29
... Option IPU, 30 ... ISIC board, 31 ... S
CSI board, 32 ... SCU, 33 ... NIPU, 34 ...
Connector, 35: Memory control unit, 36: RO
M, 37 ... CPU, 38 ... RAM, 39, 40, 41 ...
Pull-up power supply, 42 ... SW.

Claims (4)

[Claims] 1. A document reading means for reading an image of a document to be read in a desired reading cycle line by line, a step motor for moving the document reading means or the reading document in a sub-scanning direction, and a step motor for driving the step motor A reading control unit that controls reading of the image with the predetermined number of clock pulses as the desired reading period, an image memory that stores image data read by the document reading unit, and controls the image memory. A memory controller and a plurality of interfaces for controlling output of the image data to an external device,
An image reading apparatus, wherein a moving speed of the document reading means or the reading document in the sub-scanning direction by the step motor can be changed according to the selected capability of the interface. 2. The image reading apparatus according to claim 1, further comprising: an interface selecting unit that selects one of the interfaces, wherein the stepping motor reads the original or the original according to the capability of the selected interface. An image reading apparatus, wherein the moving speed of the read document in the sub-scanning direction can be changed. 3. The image reading apparatus according to claim 1, further comprising: a reading speed selecting unit configured to select the original reading unit by the step motor or a moving speed of the read original in a sub-scanning direction. Reader. 4. The image reading apparatus according to claim 2, further comprising: an interface detecting unit for automatically detecting a selected interface, wherein said stepping motor reads said document in accordance with the capability of said automatically detected interface. Alternatively, the moving speed of the read document in the sub-scanning direction can be changed.