JPH09214713A - Picture reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize speed for reading a large quantity of pictures, which is suitable for the ability of an external device without mounting a large quantity memory by reading an original at proper reading speed against the external device with different transfer speed. SOLUTION: A picture data holding means (DRAM) 40 temporarily preserving information of a read original picture and a transfer means 22 transferring picture data which is taken-out from the picture data holding means to the external device are provided. Moreover, a sub-scanning speed setting means optionally setting reading speed in a sub-scanning direction, the overflow detecting means 22A of the picture data holding means and an overflow reporting means reporting overflowing to the external device are provided so that the external device is urged to re-transmit picture data when the overflow detecting means 22A detects overflowing and sub-scanning speed in succeeding time reading is delayed for the portion of prescribed speed by the sub- scanning speed setting means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading device,
More specifically, the present invention relates to an image reading device that transfers image data to an external device (host computer).

[0002]

2. Description of the Related Art In an image reading apparatus that transfers image data to an external device (host computer), the speed of reading an original is set uniquely by a preset reading density. Also, the image data transfer speed with the external device that receives the image data is fixed depending on the processing speed of the external device. Therefore, when a predetermined number of image data is transferred from the image reading device to the external device by the reading device and the reading area, if the image data transfer speed is faster than the reading speed of the original, the image data is stuck in the image data holding means. However, if the image data transfer speed is slower than the original reading speed, the image data holding means overflows, and there is a problem that the image data cannot be transferred. Further, if the reading speed itself is slowed down, overflow will not occur, but uniform reading will be slowed even for an external device having a high transfer speed, which makes it impractical.

[0003]

In the prior art for solving the above-mentioned problems, a memory is provided in an image reading device, image data is temporarily stored in the memory, and the image data external device The data was transferred according to the transfer speed. However, in the above-mentioned conventional technique, a large amount of memory is mounted, which causes a significant increase in cost and an increase in size of the device. A proposal has also been made to detect the image data transfer speed and determine the reading speed, but it has not been put to practical use due to the complicated structure.

Since the present invention has been made in view of the above-mentioned circumstances, an original is read at an appropriate reading speed with respect to an external device having a different transfer speed, so that a large amount of memory (image data holding means) is not mounted. The purpose is to realize the maximum image reading speed commensurate with the capability of the external device (with a small amount of memory installed).

[0005]

According to a first aspect of the present invention, there is provided a reading unit for reading an original image, an image data holding unit (DRAM) for temporarily storing information (image data) of the read original image, and In an image reading apparatus having a transfer means for transferring image data taken out from the image data holding means to an external device, a sub-scanning speed setting means capable of arbitrarily setting a reading speed in the sub-scanning direction and overflow detection of the image data holding means. Means and an overflow notification means for notifying the external device of the overflow, and when the overflow detection means detects the overflow, prompts the external device to retransmit the image data, and the sub-scanning speed setting means The feature is that the sub-scanning speed in reading is slowed down by a predetermined speed. Without providing the image data holding means (DRAM), it is obtained to forward the image data to an external device (host computer).

The invention of claim 2 is characterized in that, in the invention of claim 1, the sub-scanning speed setting means is set so that the sub-scanning speed becomes the earliest value in the first image reading after the power is turned on. Therefore, after the power is turned on, the image is read by assuming the fastest transfer speed, and the reading can be performed on an external device having a high transfer speed without killing the high transfer speed.

According to a third aspect of the present invention, in the first aspect of the present invention, the sub-scanning speed is stored in the non-volatile memory, and the sub-scanning speed setting means is set so as to have the value of the non-volatile memory after the power is turned on. It is characterized by setting, so that the automatically adjusted reading speed is retained in the non-volatile memory, and re-execution of automatic adjustment operation while generating an overflow when the power is turned on again is omitted. .

The invention of claim 4 is characterized in that, in the invention of claim 3, means for initializing the sub-scanning speed to the earliest value is provided, and thus the reading held in the non-volatile memory is carried out. The speed was initialized so that even if an external device with a higher transfer rate was exchanged, reading could be performed without killing the high transfer rate.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall configuration diagram for explaining an example of an image reading apparatus to which the present invention is applied. As is well known, a document placed on a platen glass 1 is illuminated. The light reflected by the lamp 3 is reflected by the first mirror 2, the second mirror 4, and the third mirror which are integrally formed with the illumination lamp.
It is scanned by the mirror 5. Then, the reflected light is reflected by the lens 38.
The light is collected by the light source, is irradiated onto the CCD 6, and is photoelectrically converted. The first mirror 2, the illumination lamp 3, the second mirror 4, and the third mirror 5 are movable in the A direction by using the traveling body motor 7 as a drive source.

Documents stacked on the document tray 8 are picked up by a pickup roller 9, a pair of registration rollers 10 and a conveying drum 1.
1, the feeding roller 12 passes through the reading position B, is fed to the pair of paper ejection rollers 13 and 14, and is ejected onto the paper ejection tray 15. When the document passes the reading position B,
It is emitted by the illumination lamp 3 which is moved to the vicinity of the reading position B, and the reflected light is scanned by the first mirror 2 and the second mirror 4 and the third mirror 5 which are integrally formed. After that, the reflected light is condensed by the lens 38, and the CCD 6
And is photoelectrically converted. The pickup roller 9 and the registration roller pair 10 are driven by a paper feed motor (not shown), and the transport drum 11, the transport roller 12, and the paper discharge roller pairs 13 and 14 are driven by a transport motor 16.

FIG. 2 is a block diagram for explaining an example of an image reading apparatus to which the present invention is applied. As is well known, reflection of an original incident on a CCD 6 on an SBU (Seven Board Unit) 17 is reflected. The light is converted in the CCD 6 into an analog signal having a voltage value according to the light intensity. The analog signal is divided into odd bits and even bits and output. The analog image signal is an MBU (Mother Board Unit).
AHP (Analogue data Handling Periphera) on 18
In l) 19, the dark potential portion is removed, the odd bit and the even bit are combined, and the gain is adjusted to a predetermined amplitude, and then input to the A / D converter and converted into a digital signal. The digitized image signal is SCU (Scanner Co
SIP (Scanner Imaging Periph) on the ntrol unit)
eral) 21, shading correction, gamma correction, MT
After F correction etc. is performed, it is binarized and the page synchronization signal,
It is output as a video signal together with the line sync signal and the image clock.

The video signal output from the SIP 21 is
IEU (Image Enhance Unit) 2 via connector 29
It is output to 8. The video signal output to the IEU 28 is subjected to predetermined image processing in the IEU 28, and the SCU
20 is input again. The video signal input to the SCU 20 again is input to the selector 30. Selector 30
The other input is a video signal output from the SIP 21, and the IEU 28 can select whether to perform image processing. The output of the selector 30 is input to the selector 31. The other input of the selector 31 is an RCU (Reverse Sise Control Unit) 3
The video signal is from 2, so that the reading surface of the original can be selected.

The RCU 32 is a unit for controlling the back side reading of the original when simultaneously reading both sides of the original. The RCU 32 is controlled by the CPU 25 in the SCU 20 by serial communication, and transfers the read back side image data to the SCU 20 via the MBU 18 as a video signal. The video signal output from the selector 31 is the selector 3
2 and the connector 33. The other input of the selector 32 is a video signal from the video adapter 39. With the above configuration, the video adapter 39 can be connected to the end of the connector 33. Selector 32
The video signal output of is input to the SBC 22.

The video signal output from the SIP 21 through the above path is used as an SBC (Se) for managing the DRAM 40.
an Baffer Controller) 22 and SIMM (Si
nglInlin Memory Module) 23 and stored in the image memory constituted by DRAM 40. The image data stored in the image memory is stored in the selector 34 and the connector 35.
It is connected to the. The connector 35 has a DCU (Data C
ommpression unit) 36 is connected, and DCU36
Compresses the input image data. The image data compressed by the DCU 36 becomes the other input of the selector 34, and the image data can be compressed or not compressed. The image data output of the selector 34 is sent to the host computer through the SCSI controller 24.

A CPU 25 and a ROM 2 are provided on the SCU 20.
6, RAM 27 is mounted and controls the SCSI controller 24 to communicate with the host computer.
The CPU 25 also controls the timing of the traveling motor 7, which is a stepping motor, the paper feed motor, and the carry motor 16. The ADU 37 is an automatic document transport mechanism (AD
It has a function of relaying the power supply of the electrical components used in the F) section.

FIG. 3 is a diagram for explaining the structure of the overflow detection unit 22A provided in the SBC 22, and FIG. 4 is a time chart for explaining the operation thereof. The SBC 22 validates the image data DIN. Gate (I
While the GATE is active, the clock (ICL
K) and the data is written to the DRAM 40. Similarly, the image data (DOUT) is transferred to the valid gate (OGAT).
E) is read from the DRAM 40 and output in synchronization with the synchronous clock (OCLK) while E) is active. As shown in FIG. 5, in the overflow detection unit 22A, counters 22a1 and 22a2 that count up in synchronization with the synchronous clock while the valid gate is active are provided for each input and output, and the number of data stored in the DRAM 40 is set. Can be counted. The count value is CP
It is connected to the U bus and can be read from the CPU 25. Also, a signal (CLEAR) for clearing the counters is prepared by an instruction from the CPU 25, and both counters are initialized before the image reading is started.

The amount of data stored in the DRAM 40 is
It is the value obtained by subtracting the output counter number from the input counter number.
Both counter numbers can be read by the CPU 25.
You can see if it is saved in 40. CPU2
5 is the amount of DRAM 40 stored in advance and the current DRA
The amount of data held in M40 is compared, and the DRAM4
If the amount of 0 is smaller, it is determined that an overflow has occurred, the reading operation is stopped, and the host computer is notified that an overflow has occurred. The host computer notified that the overflow has occurred requests the reading again.

FIG. 6 is a flow chart for explaining the operation of the present invention. When the power is turned on, the contents of the nonvolatile memory are checked (S1). If the initial value is set, the thinning pattern and the sub-scanning reading speed are set. Is set to the earliest combination (S2). If the command to clear the non-volatile memory comes (S
3), the nonvolatile memory is set to the initial value (S4). When a reading start command is received (S5), the thinning pattern and the sub-scanning reading speed are set according to the contents of the nonvolatile memory, the input / output counter is cleared (S6), the reading is started (S7), and the image data is stored in the DRAM. And write it to the host computer (S8). Overflow is detected during the reading (S9), and if the overflow is detected, the reading is interrupted (S10) and the host computer is notified that the overflow has occurred (S11). The host computer notified of the overflow again instructs to start reading (S3). When the output of all data is completed without overflow (S12), the current thinning pattern and the sub-scanning reading speed are written in the nonvolatile memory (S13), and the reading operation is completed.

The digitized image data is input to the SIP 21 line by line. The line cycle of input image data is constant regardless of the reading density. SI
P21 is equipped with a line thinning circuit for thinning image data line by line, and arbitrarily thins image data line by line according to a thinning pattern set by the CPU 25. The SIP 21 is provided with a thinning pattern setting register, and thins lines according to the value set by the CPU 25.

(Example) Setting value of thinning pattern setting register (binary expression) 1010 1010 → thinning every other line 1110 1110 → thinning once every 4 lines

The CPU 25 controls the timings of the traveling body motor 7 and the conveyance motor 16 to arbitrarily set the sub-scanning reading speed. The combination of the thinning pattern and the sub-scanning reading speed is determined by the combination of the reading density preset by the external device and the image data transfer rate determined by the image data transfer rate detecting means.

Below, the reading speed of the original by the CCD is 1 Mbyte / sec (8 Mdot / sec) and the line cycle is 6
A case of a reading device having a basic reading density of 400 dpi at 25 usec (5000 dots / line) will be described as an example. If the preset read density is 400 dpi and the image data transfer rate is 1 Mbyte / sec, and the thinning pattern is 11111111 (no thinning), the time required to read 1 inch is 250 msec (625 ×
400usec), the sub-scanning reading speed is 10
It is 1.6 mm / sec. If the preset read density is 200 dpi and the image data transfer rate is 1 Mbyte / sec, and the thinning pattern is 11111111 (no thinning), the time required to read 1 inch is 1
Since it is 25 msec (625 × 200 usec), the sub-scanning reading speed is 203.2 mm / sec. If the preset read density is 400 dpi and the image data transfer rate is 0.5 Mbyte / sec, overflow will always occur without thinning.
101010, and the sub-scanning reading speed is 50.
Slow down to 8mm / sec. Table 1 shows the summary.

[0023]

[Table 1]

After the power is turned on, in the reading operation of the first sheet, the CPU 25 prevents the overflow from occurring.
Make the sub-scanning reading speed the fastest (set to no thinning). After that, when an overflow is detected, the sub-scanning reading speed is decreased by a predetermined amount and the thinning pattern is increased by a predetermined amount. The CPU 25 holds the set sub-scanning reading speed and thinning pattern in the non-volatile memory, and when the power is turned on next time, the reading is started at the held sub-scanning reading speed and thinning pattern. Also, an instruction for initializing (making the fastest) the sub-scanning reading speed and the thinning pattern is prepared from the host computer, which is used when another (faster) host computer is connected.

[0025]

According to the first aspect of the present invention, image data can be transferred to an external device (host computer) without providing a large amount of image data holding means (DRAM), so that the product can be constructed at low cost. it can.

According to the invention of claim 2, after the power is turned on,
Since the image is read assuming the fastest transfer rate, it is possible to read the external device having a high transfer rate without sacrificing the high transfer rate.

According to the third aspect of the invention, since the automatically adjusted reading speed is held in the non-volatile memory, it is possible to omit re-execution of the automatic adjustment operation while causing an overflow when the power is turned on again. .

According to the invention of claim 4, since the reading speed held in the non-volatile memory is initialized, even if the external device having a higher transfer speed is replaced, the high transfer speed is killed. The reading can be carried out without.

[Brief description of 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 a block diagram for explaining an example of an image reading apparatus to which the present invention is applied.

FIG. 3 is a block diagram showing a configuration of an overflow detection circuit unit used for implementing the present invention.

FIG. 4 is a time chart for explaining the operation of the overflow detection circuit.

FIG. 5 is a diagram for explaining details of an overflow detection circuit.

FIG. 6 is a flowchart for explaining the operation of the overflow circuit.

[Explanation of symbols]

1 ... Platen glass, 2 ... First mirror, 3 ... Illumination lamp,
4 ... Second mirror, 5 ... Third mirror, 6 ... CCD, 7 ... Traveling motor, 8 ... Document tray, 9 ... Pickup roller, 10 ... Registration roller, 11 ... Conveying drum, 12 ...
Conveying rollers, 13, 14 ... Ejecting roller pair, 15 ... Ejecting tray, 16 ... Conveying motor, 22 ... SBC, 22A ... Overflow detecting section, 38 ... Lens, 40 ... DRAM.

Claims (4)

[Claims] 1. A reading means for reading an original image, an image data holding means for temporarily storing information of the read original image, and a transfer means for transferring the image data taken out from the image data holding means to an external device. In the image reading apparatus having the above, there is provided sub-scanning speed setting means capable of arbitrarily setting the reading speed in the sub-scanning direction, overflow detecting means of the image data holding means, and overflow notifying means notifying an external device of the overflow. However, when the overflow detecting means detects an overflow, the external device is prompted to retransmit the image data, and the sub-scanning speed setting means slows the sub-scanning speed in the next reading by a predetermined speed. . 2. The image reading apparatus according to claim 1, wherein the sub-scanning speed setting means is set so that the sub-scanning speed becomes the fastest value in the first image reading after the power is turned on. 3. A sub-scanning speed is stored in a non-volatile memory,
2. The image reading apparatus according to claim 1, wherein the sub-scanning speed setting means is set so as to have a value of the non-volatile memory after the power is turned on. 4. The image reading apparatus according to claim 3, further comprising means for initializing the sub-scanning speed to a maximum value.