JPS6065660A - Original reader - Google Patents

Abstract

PURPOSE:To make reading of original efficient by measuring the elapsed time of extinguishment of preceding reading operation, and changing a preparatory light time to eliminate the unnecessary preparatory lighting time. CONSTITUTION:When a reading signal enters a scanner control circuit 8, the count of a counter 12 is stopped, a signal is transmitted to a fluorescent lighting device 9 to light a illuminating light source. A scanner control circuit 8 obtains a fluorescent light extinguishing time of the illuminating light source from the count number. The preparatory lighting time is obtained by operation from the extinguishing time obtained in this way. When the preparatory lighting time is elapsed, the scanner control circuit 8 gives a forward driving signal to a motor of a driver 10 to start the reading of the original.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a document reading device that breaks down image information on a document into minute parts and reads them as electrical signals.

<Prior Art> Recently, in addition to the processing of code information H that has been carried out for a long time, processing as image information has been implemented.

In this image processing, a document reading device functions as an input unit for inputting image information. Initially, the input section of a facsimile machine was used as the original document reading device, but as there was a demand for inputting image information at higher speed and with greater precision,
Dedicated manuscript reading devices became available.

Furthermore, there is now a need for a document reading device that can suitably handle various types of documents, such as book-shaped documents, without being limited to sticker-shaped documents.

Here, the general structure of the document reading device will be explained.

A line image sensor in which a plurality of pixels are arranged in a straight line is used as a reading element.11 A typical example is a COD line image sensor of an IC sensor.

The length of the sensor is usually less than 30 minutes.

On the other hand, the reading width of a document is, for example, the short side of A3 paper is 29
Therefore, an optical system is required to form a reduced image of the document onto the pixels of the sensor.

A lens unit composed of a plurality of lenses is used as this optical system.

Further, the reading surface of the document is irradiated with light by an illumination light source such as a halogen lamp or a fluorescent lamp.

The above document, sensor, lens unit, and illumination light source move relative to each other in a direction perpendicular to the reading line, and correspondingly, electrical signals corresponding to the contents of the document are sequentially extracted from the pixels of the sensor, and as a result, the document The content information is converted into electrical signals.

Methods for relatively moving the document, sensor, lens unit, and illumination light source include a method in which the document is moved using a feed roller, a method in which the document table on which the document is placed is moved, and a method in which the document is fixed and the lens unit and sensor are moved relative to each other. There is also a method in which the illumination light source moves together, and a method in which the document, lens unit, and sensor are fixed, and a reflecting mirror in the middle of the C optical path and the illumination light source are moved.

Therefore, we will discuss the above-mentioned document reading device in which the reflection mirror and the illumination light source move in the middle of the optical path.

FIG. 1 shows the structure of the document reading device.

In the figure, a document 1 is placed on a document table 2 made of transparent glass. At this time, the original 1 is placed so that the surface to be read is in contact with the original table 2.

The image of the document l on the document table 2 passes through the reflection mirror 3 and the reflection mirror 4, and is formed as a reduced image by the reading lens unit 5 on the pixel surface of the reading element section 6b.

When the reading of the original is started, the illumination light source 7 starts to move and illuminates the reading part of the original 1 through the original platen 2 with a brightness that allows the reading element section 6 to sufficiently read the information of the original image.

Subsequently, the illumination light source 7 and the reflection mirror 3 start moving in the direction indicated by arrow A while maintaining the same distance from the original document editor.

In synchronization with this, the reflecting mirror 4 starts moving in the direction of arrow B by a moving amount that is half the moving amount of the illumination light source 7 and the reflecting mirror 3.

Therefore, the optical path length from the document surface to the reading element section 6 is determined by the illumination light source 7. It remains the same despite the movement of the reflecting mirrors 3 and 4.

In this way, all information on the document surface is transmitted to each pixel on the reading element section 6 by moving the illumination light source 7 and the anti-fouling mirror 3 below the document 1 from right to left in the figure.

At that time, the movement of the illumination light source 7 and the reflection mirror 3 is
At a timing corresponding to Ii, an electrical signal is extracted from the reading element section 6 according to the brightness of the image formed.

When the document reading is completed, the illumination light source 7 is turned off,
The illumination light source 7 and the anti-fouling mirrors 3 and 4 start moving in the opposite direction to the reading direction and return to the initial setting position (standby position).

By the way, when starting reading, the illumination light source 7L
The force of A's A force ≦ - murmur The power of A's 7 does not reach a constant value during sleep, but gradually increases due to light and gradually converges to a constant value.

Therefore, the lighting and reading operations will be explained using the timing chart shown in FIG. 2.

When the reading command signal S is input, the illumination light source turn-on signal s2 is output at the same time to instruct lighting. The signal S3 for operating the light source (not shown) was output after a predetermined time (preliminary lighting time) T had elapsed after the signal S2 was output.

As shown in FIG. 3, the light intensity of the illumination light source 7 rises when the temperature inside the illumination light source 7 is high (as shown by curve a).
and when the temperature inside the illumination light source 7 is low (as shown by the curve)
In other words, when the temperature inside the illumination light source 7 is high, the light amount rises faster than when the temperature inside the illumination light source 7 is low.

That is why, conventionally, the above-mentioned time T is the illumination light source 7
It was determined with some margin so that even if the internal temperature is low and the light intensity rises slowly, the change in the light intensity will be small within the reading time.

However, when performing reading operations continuously, at the start of reading, the temperature inside the illumination light source 7 is high due to the residual heat from the lighting of the previous reading operation, and the rise in the light intensity of the illumination light source 7 is Inevitably it will be faster.

This is why, in conventional document reading devices, there is an unnecessary pre-lighting time during high-speed continuous reading.

<Object of the Invention> In view of the above matters, the present invention provides a preliminary lighting time, (a) a time proportional to the off time of the illumination light source up to a predetermined value, and (b) a time proportional to the off time of the illumination light source up to the predetermined value. It is an object of the present invention to provide a document reading device that eliminates unnecessary pre-lighting time by appropriately changing the time by setting the time to a fixed length when it exceeds a value, and enables speedy continuous reading.

<Example> The configuration of the present invention will be described below with reference to embodiments.

The document reading device of the present invention is characterized in that the preliminary lighting time is changed by measuring the elapsed time from when the light source was turned off, that is, turned off during the previous reading operation. Since the structure itself is the same as that shown in FIG.
Use diagrams.

As shown in FIG. 4, the document reading device according to the embodiment of the present invention is provided with a scanner control circuit 8 for controlling a scanner (scanning system), and includes a scanner control circuit 8i, a trowel, and a fluorescent lamp of an illumination light source 7. The configuration is such that the lighting device 9 and the drive device 10 are controlled.

The scanner control circuit 8 receives the output of a sensor 11 that detects whether the illumination light source 71 and the reflecting mirrors 3 and 4 are in the standby position.

Further, the scanner control circuit 8 is connected to a counter 12 and an arithmetic circuit 13.

Next, the operation of the control mechanism section will be explained according to the flowchart shown in FIG.

When the original reading device finishes reading the original (step S), the scanner control circuit 8 sends a turn-off signal to the fluorescent lamp igniter 9 to turn off the illumination lights #7 (step S2). At the same time, the scanner control circuit 8 sends a count start signal to the counter 12 to start counting (step S3).

Next, the scanner control circuit 8 sends a reverse rotation signal to the drive device 10 to start the reverse rotation of the motor of the drive device 10 (step S4). In this way, the illumination light source 7 and the reflecting mirror 3.4 return to the standby position according to the operation of the driving device 10 (step S5). This return is detected by the sensor 11, and upon receiving an input from the sensor 11, the scanner control circuit 8 stops the drive device 10 (step S6).

In this state, the scanner control circuit 8 waits for the next reading command (S, step).

When the next read signal enters the scanner control circuit 8, the scanner control circuit 8 first sends a count stop signal to the counter 12, and the counter 12 stops counting (SS step).

Subsequently, the scanner control circuit 8 sends a lighting signal to the fluorescent lamp igniter 9 to turn on the illumination light source 7 (S9).
Step) 1. Here, the scanner control circuit 8 controls the counter 1.
From the count number 2, the distance t between the fluorescent lamp lights of the illumination light source 7
Obtain o (S1o step).

This obtained light-off time t. Accordingly, the scanner control circuit 8 executes the following calculation using the arithmetic circuit 13 to determine the preliminary lighting time T. I put it on.

That is, (a) lights-out time t. or less than 10 seconds (S11 step → S12 step → S13 step) T 1 = a
Xt.

(where a is a constant) o −T1 (b) Lights-off time [. is 10 seconds or more (step S11 → step S14) TO=Tmax (however, -Tmax is a preset constant value) Note that this light-off time to and preliminary lighting time T. Toke 6th
The relationship is as shown in the graph in the figure.

Then, the scanner control circuit 8 calculates the preliminary lighting time T determined by the calculation from the time when the illumination light source 7 is turned on in the 59 steps described above. elapses (Sl.

Step), a forward rotation signal is sent to the motor of the drive device 10, and as a result, the motor of the drive device 10 starts rotating forward (S, 6 steps). In this way, the scanner control circuit starts reading the document again (S17
step).

The same operations below can be repeated as necessary.

Note that the present invention is of course not limited to the above-mentioned embodiments, and if there is a more efficient relationship between the preliminary lighting time and the lights-out time, it may be possible to use it.

Effect> As described above, according to the present invention, the document table on which the document is placed;
In a document reading device that has a light source, an optical system, and a drive section, and scans the document by changing the relative position of the document table, the light source, or the optical system by the operation of the drive section and reads the document. Since an appropriate time from turning on the light source to operating the drive unit is selected depending on the length of time from turning off the light source to turning on the light source again, the document can be read efficiently, and It becomes possible to read the original with uniform density, and it is possible to prevent deterioration in image quality due to differences in density.

[Brief explanation of the drawing]

Fig. 1 is a structural diagram of a document reading device to which the present invention can be applied, Fig. 2 is a timing diagram of document scanning, Fig. 3 is a graph showing the relationship between lighting time of the illumination light source and light amount, and Fig. 4 is a diagram of the present invention. FIG. 5 is a block diagram of the control section characterizing the control section, FIG. 5 is an operation flowchart of the control section, and FIG. 6 is a diagram showing the relationship between the illumination light source and preliminary lighting time embodied in the present invention. . ;1. 1, ]...,] - manuscript 2... manuscript table, 3, 4... reflective mirror, 5..."(,": mark removal lens - red, 6... reading element section, 7 ...Illumination light source, 8 ・
Scanner control circuit. 9... Fluorescent lamp ignitor, lO... Drive device, 11...
・Sensor, 12・Counter, 13...Arithmetic circuit. Agent Patent Attorney Aihiko Fukushi (2 persons) 1st 1st 2nd E beat k, Tane Sakishima 4th illustration nm16-□

Claims (1)

[Claims] A document reading device that reads a document by scanning a document table, a light source, an optical system, and a document on which a document is placed, and the time from the time when the light source is turned off at the end of reading to the time when the light source is turned on again. A document reading device comprising a control means for changing the time from lighting of a light source to operation of the drive section.