JPH02294158A - Image reader - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an image reading device.

[Prior Art] A conventional image reading device scans and moves a CCO, a photoelectric conversion element, etc. relative to the surface of a document, reads an image or printed information on the document, converts it into an electrical signal, and converts the image and printed information into an electrical signal. was converted into a binary or multivalued parallel electrical signal, and the signal was transferred to an external device such as a host computer. This type of image reading device is an interface for transmitting a photoelectrically converted binary or multivalued image signal to an external device such as a host computer at high speed and economically, or for receiving it from an external device. Therefore, it was considered effective to use a bidirectional parallel interface. [Problems to be Solved by the Invention] However, when using a bidirectional parallel interface, the signal lines for handshaking with the host computer, ΔCK signal (acknowledge signal), [lUSY (busy signal), ST8 4
8"+ (strobe signal) and control the interface, especially when controlling an interface that allows the transfer to be interrupted due to the host computer's convenience during image signal transfer, it is necessary to increase the transfer rate. The problem was that it was not possible.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide an image reading device that can change the transfer rate of image signals depending on the processing speed of the interface of a host computer.

[Means for Solving the Problem] In order to achieve such an object, the present invention provides an image reading device having a reading means for reading an image, in which image information read by the reading means is set by an external device. It is characterized by comprising a first transfer means for transferring data to an external device according to the transfer speed. The present invention also provides an image reading device having a reading means for reading an image, including a setting means for setting a transfer speed according to the amount of image information in the main scanning direction read by the reading means, and a setting means for setting a transfer speed according to the amount of image information in the main scanning direction read by the reading means. and a second transfer means for transferring the image information read by the reading means to an external device at a transfer speed of 100.degree.

[Function] In the present invention, the image information read by the reading device is transferred to the external device by the first transfer device according to the transfer speed set by the external device.

Further, in the present invention, the transfer speed is set by the setting means according to the amount of image information in the main scanning direction read by the reading means, and the image information read by the reading means is transmitted at the transfer speed set by the setting means. Transfer it to an external device using the second transfer means. [Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

1 to 3 show one embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a document image reading device that reads a document image.

2 is a scanning optical system as a reading means, which includes an original illumination unit 15, a reflection mirror 16, a lens 14, a CCO 12,
It consists of a CCD driver l6. The lighting unit 15 has a lighting device FL, and is movable in the direction A in the figure. The reflecting mirror l6 regulates the optical path L of the reflected light from the document surface. The lens l4 converges the reflected light.

C(:D 12 is arranged in an array corresponding to one line in the main scanning direction of the document, and photoelectrically converts the reflected light converged by the lens 14. CCD driver 1
6 drives the CCD 12.

Reference numeral 11 is a control unit that controls each part; reference numeral 17 is a platen glass for regulating the surface of the original to be read flat; reference numeral 18 is the original placed on the platen glass 17;
l9 is the platen cover. , 20 are pulse motors for moving the document illumination unit 15 in eight directions in the figure.

In FIG. 2, 12 to 14 and 18 indicate the same parts as in FIG.

(Cl'; D driver 13) 201 is an amplifier (AMP) that amplifies the output of the CCD 12. 202 is an A/D converter (A/D)
This converts the analog signal from the amplifier 201 into an 8-bit digital signal. 203 is a CCD driving circuit, which controls the reading timing according to a timing signal supplied from the control unit 1l (:C
D12.

(Control unit 11) 204 is a D flip-flop that latches the output of the A/D converter 202 using the image sample clock. A binarization circuit 205 binarizes an 8-bit image signal according to a slice level (threshold) set in advance by CPIJ 214. 206 is a packing circuit that performs serial-parallel conversion of the binarized signal and converts it into an 8-bit (I byte) signal. 207 is a selector circuit, GPIJ 21
A209 is a clock thinning circuit that selects either 8-bit multi-value or binary according to the PMO [IE number set in advance in 4 and outputs it to the D flip-flop 208. It generates a sampling clock (KWA) for realizing scaling and resolution conversion.

210 is a buffer RAM control circuit, which controls the buffer RAM (
For example, it controls writing to a 32K byte SRAM) 211. 212 is an address generation circuit that generates an address for the buffer RAM 211. When writing, the address changes according to the clock WACK from the buffer RAM control circuit 210, and when reading, the address changes according to the clock R from the timing signal generation circuit 215.
Due to CLκ, the address changes only when the signal RE from the interface circuit 213 is "0". 213 is an interface circuit that generates a strobe signal STB when outputting an image signal. Transfer start signal from CPtl 214 The TRNS outputs the GASTB signal while monitoring the GABtlSY signal from the selector 222, and further outputs the read address count enable signal 11E to the address generation circuit 212 in correspondence with the GASTB signal to confirm that the transferred data is valid. A section signal HENB indicating the interval signal HENB is output to the interface.

In FIG. 3, output data from the buffer RAM 211 is latched by a D flip-flop 218 using a signal MRDLC from an interface control circuit 221. Image data from D flip-flop and CPII
Report data from 214 is output onto the interface through buffer 219, and human input data is input to CPU 214 through inverter 220.

222 is a selector that selects the CPI according to the transfer mode set in advance by a command from the host computer.
Transfer mode switching signal SE output from I214
L selects the GASTB signal output from the interface control circuit 221 as the first and second transfer means and the manually input G A B 11 S Y {i. For example, when transferring at high speed, S
By setting the EL signal to rlJ, GABUSY No. 8 is fixed at "0" and a constant clock VC signal κ (for example, LM}IZ) is output to the STB signal. Furthermore, the BLISY signal from the host computer can be accepted by setting the SEL signal to "0".

FIG. 4 shows an example of the control procedure stored in the second diagram R (IM 223).

Before starting reading, it is determined in step Sl whether or not there is an instruction for high-speed transfer mode, and as a result of the determination,
If there are no high-speed transfer instructions, proceed to step S2,
In step S2, the SEL signal is set to "1" to set the high-speed transfer mode. Then, in step Sδ, it waits until the read command is sent out, and starts reading when the read command is received.

On the other hand, if the result of the determination in step 51 is that there is no high-speed transfer instruction, the process moves to step S3, and the process proceeds to step S3.
At step 3, set the SEL signal to "0" and set the normal transfer mode. Then, in step S4, it is determined whether or not the pre-instructed number of transfer data exceeds 500 bytes per line, and if the result of the determination is that it does not exceed 500 bytes, the process moves to step S6. On the other hand, 50
If it exceeds 0 bytes, proceed to step S5,
In step S5, sEt. <G is set to r1, high-speed transfer mode is set, and the process moves to step S6. In this embodiment, an example has been described in which the transfer mode is switched according to a command from the host computer. However, when the number of output data per line is large, for example, in the case of multivalue mode, the CPtl 214 as a setting means It may also be possible to automatically switch to a high-speed transfer mode on the side.

[Effects of the Invention] As explained above, according to the present invention, the above configuration has the effect that the transfer rate of image signals can be changed according to the processing speed of the interface of the host converter. .

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of the embodiment of the invention, and FIG. 2 is a diagram showing the structure of the CCD driver l3 and control unit l1 of the embodiment of the invention.
3 is a block diagram showing the interface control circuit 221, and FIG. 4 is a flowchart showing an example of a control procedure stored in the ROM 223 shown in the second diagram. DESCRIPTION OF SYMBOLS 11... Control unit, l2... CCD photosensor, l3... CCD driver, l4... Lens, l5... Original illumination unit, l6... Reflection mirror 214-CPIJ, 221... Interface control circuit, 223...
IIOM. A2 November → A1 Cutlery wood 1st style harry (1 [#'l#ko, 2, nt CCD light ℃ ri'ri' CCD dryer'' ,,} 16: 7X square 1 square 17: Automatic glass 18; Original 19; Atsushi cover 20: Hals motor Figure 1

Claims (1)

[Scope of Claims] 1) In an image reading device having a reading means for reading an image, a first transfer means for transferring image information read by the reading means to an external device according to a transfer speed set by the external device. An image reading device comprising: 2) In an image reading device having a reading means for reading an image, a setting means for setting a transfer speed according to the amount of image information in the main scanning direction read by the reading means, and a transfer speed set by the setting means. An image reading device comprising: second transfer means for transferring image information read by the reading means to an external device.