JPS6031358A - Original reader - Google Patents

Abstract

PURPOSE:To prevent a shift at the joint of sensors by arranging plural line sensors while making the reading position different and outputting the output of preceding scanning with a prescribed time of delay. CONSTITUTION:Plural line sensor chips 1-4 are arranged in zigzag and ineffective photodetectors are provided to the overlapped part of each chip. The preceding chips 1, 3 are provided with a vertical CCD register to transfer an electric charge outputted from the shift gate of the chip in parallel. The outputs of the sensor chips 1, 3 are delayed by a time corresponding to the shift of the reading position. A clock CLK eliminating the transfer clock of dummy picture element's share is fed to a dither counter 76 from a controller 90. Thus, the matrix of a dither ROM75 is not discontinuous at the joint between the chips 1 and 2. A dot data obtained by comparing the value of the dither ROM75 and a picture signal is stored to any of RAMs 77, 78. The dummy component is not stored in the RAMs 77, 78 similarly as mentioned above. The RAMs 77, 78 are operated alternately and a continuous output is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a document reading device that photoelectrically reads image information on a document.

2. Description of the Related Art A line sensor is known in which a plurality of light-receiving elements made of amorphous silicon or the like are arranged in a line across the width of the document to be read in order to photoelectrically read the shading of the document image.

Now, the edge direction (approximately 210 degrees) of an A4 size manuscript is 16 degrees.
If you read it at the same pixel/tomo resolution, it will be about 600 pixels.
One line sensor with approximately 515,011 light receiving elements on a substrate of 1.0 mm is required. However, it is difficult to form such a large number of light-receiving elements on the same substrate without missing parts and with approximately uniform sensitivity, so unless improvements are made in yield etc., it is difficult to form them in terms of cost. is also not practical.

Therefore, it is conceivable to arrange a plurality of line sensors each consisting of about 1000 light receiving elements in the scanning direction and read one line of image by dividing it with each line sensor. In this way, the number of light-receiving elements to be formed on the same substrate is not so large, so that the yield can be improved and the above-mentioned cost problem associated with it can be solved to some extent.

However, there are invalid bits at both ends of the line sensor that cannot be used for image reading, so
When a plurality of line sensors are arranged on one line, an unreadable area occurs. Therefore, it is conceivable to arrange a plurality of line sensors in a staggered manner, for example, so that the reading lines of adjacent line sensors are different.

When multiple line sensors are arranged in a staggered manner, adjacent line sensors read different document surfaces by moving relative to each other in a direction perpendicular to the scanning direction.
There is a time difference between the signal from the first row of line sensors that scans the document in advance and the signal from the second row of line sensors that follows, which corresponds to the positional difference between adjacent line sensors. arise.

In a copying apparatus or the like that requires a high resolution such as 16 pixels per 1n, it is undesirable for this deviation to be affected by the reading of the belly map. Further, when reading a color image, this shift also affects the color balance.

Purpose The present invention has been made in view of the above points, and provides a document reading device that divides and scans a document using a plurality of line sensors, and that solves the above-mentioned problems in this divided reading and scanning. Let's take that as one thing.

Example In this example, when line scanning a document, a plurality of line sensors are arranged in a staggered manner so that the reading positions of adjacent line sensors are different, and the document is divided into three sections. Take it. Therefore, as described above, a deviation in the reading position occurs between the line sensors. Therefore, in order to obtain one line of continuous signals from image signals divided and read by multiple line sensors, at least the first scan scans the document in advance.
The signal output from the line sensor of the column @”t: '+,
"K'%"; c <Read out in synchronization with the signal output from the second column line sensor.

Here, two methods are considered: a method in which the signal read from the first column is stored after being converted into a digital signal, and a method in which the analog signal is stored before being converted into a digital signal.

The former method is preferable because it handles digitized signals, so it is easy to handle and is less susceptible to external influences. However, in order to store digital signals, a memory with an enormous capacity is required. In other words, if the digital signal is 8 bits and the deviation between adjacent line sensors is 4 lines, at least 8 bits x 1000 for one line sensor consisting of the 1000 light receiving elements mentioned above. pieces x 4 lines = 3
Another drawback is that it requires a storage capacity of 2,000 bits.

Therefore, in order to further eliminate this drawback, a method for storing analog signals before converting them into digital signals will be explained in detail.

Change Hereinafter, a detailed explanation will be given with reference to the drawings.

FIG. 1(a) shows the light-receiving surface of a multi-chip COD sensor in which a plurality of line sensor chips 4 each made of amorphous silicon or the like are arranged in a staggered manner on a substrate 5. FIG. In the figure, each line sensor chip scans in the direction of the 4-point arrow MS, and outputs O.
An analog signal corresponding to the intensity of the received light is output to the UT for each pixel in synchronization with a predetermined clock pulse.

The line sensor chips 4 each include 1056 light receiving elements, of which 1024 are used as effective light receiving elements for reading. Therefore, the total is 1024×4=4096
photodetectors are used for image reading, and for example, one photodetector in the width direction of an A4 size (210mmK297mm)
It can be read with a resolution of 16 pixels per line/++rm.

Furthermore, when reading an actual document image, this multi-chip COD sensor moves relative to the K document in a direction perpendicular to the main scanning direction of the line sensor (in the direction of arrow SS). Therefore, the line sensor chips 1 and 3 read and scan the document ahead of the line sensor chips 2 and 4 by a predetermined line (four lines in this embodiment).

Figure 1(b) shows the adjacent line sensor chips 2 and 3.
FIG. 6 and 7 are light receiving element arrays formed on the line sensor chips 2 and 3, respectively. The shaded areas indicate invalid light receiving elements that output so-called dummy bits that are not used for reading and are present in a predetermined number (six in this example) at both ends of the light receiving element row, and are ineffective light receiving elements that output so-called dummy bits that are not used for reading. are arranged at a predetermined line interval l (4 lines in this embodiment) so as to align the boundaries between the light receiving elements that are ineffective for reading and the light receiving elements that are valid for reading.

Reference numerals 8 and 9 designate shift gates that transfer and output charges accumulated in the light receiving elements of the light receiving element arrays 6 and 7 in parallel in accordance with the incident light. Reference numerals 10 and 11 designate horizontal CCD registers that transfer charges (analog signals) output in parallel from the light receiving element arrays 6 and 7, respectively, in the main scanning direction and serially in accordance with the lock. The charges transferred by the horizontal CCD register 10 are converted into voltage signals at the output section 12 for each pixel and output.

16 is a reset game for erasing the charge converted into a voltage signal in the output section 12, and the erasing operation is performed at the rear end of the transfer lock for each pixel. Note that the above-described output section and reset gate are also provided at one end (not shown) of the horizontal CCD register 11.

Between the shift gate 8 of the line sensor chip 6 and the horizontal CCD register 10, there is a droplet M ClCD that transfers the charges output in parallel from the shift gate 8 in parallel.
A register 14 is provided. Further, the shift gate 9 of the line sensor chip 4 and the horizontal OCD register 11 are directly connected.

That is, the line sensor chip 3 reads the document before the line sensor chip 2, and the time line sensor chip 6 corresponds to the deviation (interval l) in the reading position.
A vertical 00D V raster 14 is provided to delay the output of the 00D V raster. Note that the line sensor chip 1 and the line sensor chip 4 shown in FIG. 1(a) have the same structure as the line sensor chip 3 and the line sensor chip 2, respectively.

FIG. 2 is a configuration diagram of a copying apparatus to which the J multi-chip OOD sensor shown in FIG. 1 is applied. 100 is a reader unit that photoelectrically reads the original image and outputs a digital image signal V'[DEO; 200 is a digital image signal VI DEO indicating white/black output from the reader unit 100;
This is a printer unit that records images based on

In the reader unit 100, 21 is a document;
Reference numeral 2 denotes a transparent document table glass that supports it, 23 a document table cover, 24 an illumination lamp for exposing the document, 25 a reflector for efficiently imparting the light image of the illumination lamp to the document, 26
2 is a short-focus imaging lens for introducing light from the original;
7 is a signal K of the optical image formed by the lens 26.
The multi-chip OOD sensor shown in the first figure is for refurbishment. Reference numeral 28 denotes a reciprocating sensor fixing table on which the illumination lamp 24, reflector 25, lens 26 and multi-chip CCD sensor 27 are fixedly mounted, 29 a shaft holding the sensor fixing table 28, and 3° an identification table supporting the shaft. , 31 is a wire that transmits the force of the reciprocating force to the senna fixing base; 3
2 is a roller that transmits the drive of the wire 31, 53 is a drive roller that fixes the wire 31 and is connected to the rotational drive unit, 54 is a drive wire that connects the drive S end drive roller 53, 35 is a drive source and a valley terminal, 36 is a cable that leads the output from the multi-chip COD sensor 27. 37 is multichip OO
This is a control processing unit that controls the output of the D sensor 27 and the operation of the illumination lamp 24 and motor 35. 38 is a forward limit SW operated by the sensor fixing base 28. Reference numeral 59 denotes a home position sensor of the sensor fixing base 28. Reference numeral 40 denotes an operation panel through which the operator inputs copy commands and the like.

Explain the operation of the reader unit. First, operation panel 4
When a copy command is input from 0, a signal instructing lighting of the illumination lamp 24 is sent from the control processing unit 37, and the illumination lamp 24 is turned on. Next, the motor 25 is rotated forward. As a result, the sensor fixing base 28 starts moving forward in the direction of arrow A. As a result, the document 21 is moved in the sub-scanning direction by the multi-chip sensor 27, which generates an optical image 1.
By reading and scanning each line, it is converted into a stain signal. The fixed base 28 that has reached the end point of forward movement is the forward limiter) SW.
! 18, thereby causing the motor 35 to reversely rotate and start the backward movement of the fixed base 28. When the home position sensor 29 is activated, the motor 35 stops.
The sensor fixing base 27 stops at the home position.

At this time, when the multi-chip OOD sensor 27 moves forward in the A direction, that is, the sub-scanning direction, the line sensor chips 1 and 3 are reading the image of the main scanning line of the document that precedes the chips 2 and 4. become. This is the third
The timing chain shown in the figure and the multi-chip C shown in Fig. 4.
This will be explained using a configuration diagram of the OD sensor.

In FIG. 4, parts with the same numbers as in FIG. K1(b) have the same functions. 41 is an analog switch for selectively outputting the outputs of the four line sensor chips 4 according to data select signals DS1 to DS4, and φH1 to 4 are horizontal COD registers 1 of each line sensor chip 4.
Horizontal transfer lock for transfer operation of 0.11, φv
1 and φ■3 are vertical transfer locks for transferring the vertical COD registers 8 of line sensor chips 1 and 3, respectively, R31 to 4 are reset signals for the reset gates 13 of each line sensor chip, and SHi to 4 are respective Shift signals 081 to 084 for shifting the shift gates 8.9 of the line sensor chips are output signals from each line sensor chip.

As shown in the figure, line sensor chips 1 and 3, that is, line sensor chips that read originals in advance, are both provided with a vertical CCD register 14 for three lines between a shift gate 8 and a horizontal 00D register 10. Further, the pulse signals in FIG. 3 indicate shift pulses SH1 and SH2 that drive the shift gates and output parallel images. Now, considering chip 1 and adjacent chip 2, line sensor chip 1 is at the original reading start position.
While reading the first line of the document, the line sensor chip 2 is reading the thirteenth line. Thereafter, the motor 65 moves the fixed base 27 forward.
Each time the chip 1 moves by one line, the output of the chip 1 is sequentially read in the second and third lines, and when the fourth line is read, the chip 2 reads the first line.

For this purpose, if the vertical COD register provided in the line sensor chip 1 is operated by the vertical transfer lock φv1 synchronized with the shift signal SH2 given to the line sensor chip 2, the output of the line sensor chip 1 is 0.
81, the same 2-in read signal synchronized in the sub-scanning direction is output at the same timing as the output os2 of the line sensor chip 2.

Note that the output signal os1 of the line sensor chip 1 is placed within the ridge section of one line scanning section (SH section) (however, in the case of a contact type line sensor with 4 chips and n chips, the 1/n section). The horizontal transfer lock φH1 is controlled so that all pixels of the chipper are transferred from the horizontal 00D register.

Then, the read signals of all the chips 4 are sequentially transferred while changing the phase. At this time, specifically, when the transfer of chip 1 is completed, the analog switch 41 is operated sequentially such that when the transfer of chip 1 is completed, the switch for that line is turned off, and the switch for selecting the transfer output of the next chip 2 is turned on. K
: is configured so that it is output as a signal for one line that was not included. Switching of the analog switch 41 is performed in response to a data select signal Dsj~4, which will be described later.

On the other hand, the printer 200 is a laser beam printer that uses electrophotography to record an image based on the digital image signal VIDEO from the reader 00 and uses laser light.

In the printer 200, 51 is a laser unit that modulates and outputs laser light upon receiving the signal VIDEO from the reader 0Q. 52 is a scanner unit for scanning with laser light; 53 is a BD (beam detect) detection circuit that receives the laser light and outputs a BD double signal for horizontal synchronization of image recording, etc.; 54 is a photoreceptor drum; 55
56 is a high-voltage unit that supplies voltage to the charger 55; 57 is copy paper stored in a cassette; 58 is a paper feed roller that rotates to feed the copy paper; 59 is a charger that charges the photosensitive drum; A registration roller 60 is used to synchronize the leading edge of the copy paper with the leading edge of the latent image formed on the photoreceptor drum by irradiation with laser light, and 60 is a developer that converts the latent image into a visible image by attaching toner to the latent image. 61 is a transfer device that transfers a visible image onto a copy paper fed at a predetermined timing by a registration roller; 62 is a fixing device that fuses the toner on the copy paper; 65 is a device on the photosensitive drum 54 after the transfer is completed; A cleaner 64 removes unnecessary toner, and 64 is a sleep lamp that removes the potential on the surface of the photoreceptor drum.

A charger 55 charges the photoreceptor 54 with a uniform potential.

The signal VTIO from the reader section 100 is transmitted to the laser unit 5.
1 is output as a modulated signal of laser light. V
- The Units) 511d emits a laser beam modulated according to this VIDEO signal, and the laser beam is deflected and scanned by the scanner unit 52 perpendicular to the drum rotation direction.

The latent image thus formed on the photosensitive drum is visualized by the developing device 60. On the other hand, the toner on the drum is transferred to the copy paper synchronously conveyed by the registration roll 59 by the action of the transfer device 61, and then the toner image is fixed to the copy paper by the fixing device 62, and the toner image is removed from the machine. is discharged.

A specific block diagram is shown in FIG. 5.

Further, the output image timing is shown in FIG.

70a and 70k) in Fig. 5 are analog switches for switching the output 081 of chip 1, 70Q, 70d are analog switches for switching the color power 082'' of chip 2, 7ge, 7of U chip 3I) 70g, 70h
indicates each analog switch of chip 4.

(The part surrounded by the dotted line corresponds to the analog switch 41 in FIG. 4.) 71 is a sample halt circuit for making the output time of the output signal constant.

72 is an amplifier for increasing the signal; 73 is an A/D converter for converting the analog signal into a digital signal of predetermined bits; and 74 is a binary value indicating white/black by comparing the digital signal with a threshold value. Comparators 77 and 78 are dithered in the comparators according to the address.
A RAM that stores bit data obtained by comparing the OM value and image data; 79 is a selector that supplies read and write addresses to the RAM 77; 801d;
A selector 81 that supplies read and write addresses to the RAM 3B is a synchronization signal for each line coming from the printer 200, which is alternately output from the synchronization control circuit 45 every section of the 2BD section in synchronization with the signal BD busy. 82 is an oscillator for matching the signal output to the characteristics of the printer 200; 83 is a read counter that counts the oscillation clock from the printer oscillator; 84 is synchronized with the reading operation of the reader section 100; Write counter that receives the clock and counts; 85 is RAM
This is a synchronous control circuit that controls the read/write of 57.38.

86 is an oscillator that outputs a clock pulse φ that determines the transfer of the read output of the multi-chip OOD sensor, and 87 is an oscillator that synchronizes the league oscillator 86 with the BD double signal from the printer 200, and SH to the multi-chip 00D safety length. A BD synchronization circuit that generates pulses, 88 a generation circuit that generates a vertical transfer lock φU for operating the vertical transfer registers of odd-numbered COD chips, ie, line sensor chips 1 and 3, and 89 an oscillation circuit for the reader oscillator 86 A counter that performs counting operation based on signals and SR pulses, and 90 are horizontal transfer locks φH1 to φH4 and analog switches for causing all line sensor chips to perform transfer operations during the SH signal period according to the count value of the counter 89 according to the reader oscillator 86. This is a controller for generating switching signals D81 to DS4 of 41.

To explain the operation in FIG. 5, the oscillation signal φ from the reader oscillator 86 and the BD double signal from the printer 200 are synchronized by the BD synchronization circuit 47, and the waveform-shaped BD double signal SH pulse is output to the SH terminal of each chip. Enter. As a result, charges are transferred in parallel from the light receiving elements of each chip. Here, in the odd-numbered chips, that is, the line sensor chips 1 and 3 that read the document in advance, this charge is transferred in the vertical COD register 14 by the vertical transfer lock φV. Here, in the case of equal magnification writing, the same pulse as the shift pulse SH for driving the shift gate is applied as φ■.

Therefore, after being delayed by vertical 00D registers corresponding to spatially different pixels, it is outputted in synchronization with the line output of the adjacent even-numbered chip and in synchronization with the same -BD signal. At this time, the Mizuko0D register 11 of the chip 1 receives the horizontal transfer pulse φH controlled by the controller 90 as shown in the timing chart of FIG.

Otherwise, all pixels are transferred during 1/4 of the SH interval. Furthermore, it can be seen that the horizontal retraction pulse φH3 is outputted to the adjacent chip 2 after the above-described horizontal transfer pulse φH1 ends. In this way, it can be seen that the pixels of all the chips of the multi-chip OCD 7 sensor are sequentially transferred and outputted for one line to the analog switch 41 within the SR section.

In this way, when the analog switch 41 is used to connect the outputs of a plurality of line sensor chips, a delay occurs in the switching time. However, as mentioned above, since there are dummy pixels other than effective pixels before and after the output of each line sensor chip,
At this time, the analog switch 41 is configured to open the winding. or,
This dummy pixel is removed by a method described later.

Pixel data is output at analog level with a waveform. The sample and hold circuit 71 samples and holds the signal, and the amplifier 72 corrects the signal value to match the standard value of the A/D converter 73. The analog value is then A/D converted to convert the analog value into a predetermined bit. Suitable for digital signals.

This is output to the printer 200 as a dot design address indicating black and white. At this time, in order to use the dither counter, the dot data obtained by comparing the reproduced image with a defective image band, such as the second row, is stored in either of the line memory RAMs 77 and 78. At this time, first the line memory RA
M77 is selected when the VB terminal of the synchronization control circuit 85 becomes low. At this time, the selector 79 selects the write address bus from the write counter 84.

Therefore, the output of the write counter 84 is input to the address line of the RAM 77. At this time, the write counter 84, like the dither counter 76 described above,
Since the clock with the transfer lock for one dummy pixel from the controller 90 is counted, the bit data of the dummy pixel is not stored in the RAM 77.

Also, when the synchronous control circuit 85 sets WE to NO, the RAM 77
Since the write terminal WE becomes high and the chip select C8 becomes low, the data of the previous line stored in the RAM 77 is read out, and the continuous image signal V'1DEO from which one dummy pixel has been removed is read out. as printer 200
is output to. At the same time, the dot data currently output from the comparator 74 is stored in the RAM 78.

In this way, the RAMs 37 and 38 alternately perform writing and reading from the memory and output the image signal VIDEO to the printer in synchronization.

In this embodiment, the case where there are four line sensors has been explained, but this number is determined by the desired resolution, the size of the original to be read, etc., and any number of line sensors may be used. Needless to say.

Further, the present invention can be similarly implemented in a reading device using a so-called reduction optical system that is not a close reading method.

Moreover, it is also possible to use materials other than amorphous silicon, such as crystalline silicon, cadmium sulfide, etc., as the light receiving element.

Further, the arrangement of the plurality of line sensors is not limited to a staggered arrangement, and it goes without saying that the arrangement can be applied to an arrangement in which the reading positions are shifted by several lines.

Further, the output unit may also be an inkjet printer, a thermal printer, etc. other than a laser beam printer, or may be an image file for storing image data.

Effects As explained above, by reading images with multiple line sensors, we provide a document reading device that reduces line sensor yield and eliminates cost problems, and also improves the productivity between adjacent line sensors. It is possible to easily obtain a one-line image signal with no deviation, and by using the image signal obtained by this reading, it is possible to reproduce a good image without deviation.

[Brief explanation of the drawing]

Figure 1 (a) is a schematic diagram of the light-receiving surface of the multi-chip CCJD sensor, Figure 1 (b) is an enlarged view of the joint part of the line sensor chip, Figure 2 is a configuration diagram of the copying device, and Figure 3 is the reader. Timing chart diagram showing operation, Figure 4 is multi-chip O
The configuration diagram of the OD sensor, FIG. 5 is a diagram showing a specific circuit example, and FIG. 6 is a timing chart diagram showing the output state of each part, 1 to 4 are line sensor chips, 6 and 7 are light receiving element arrays, 8 and 9 are shift gates, 10 and 11 are horizontal C
OD register 14 is a vertical COD register. Applicant: Gyanon Co., Ltd., -5) Agent: Yoshifu Marushima, (;.

Claims (3)

[Claims] (1) In a document reading device in which a plurality of line sensors each consisting of a plurality of light receiving elements are arranged in the scanning direction, the plurality of line sensors are arranged at different reading positions and the document is scanned in advance. A document reading device comprising a delay means for delaying the output of a line sensor by a predetermined period of time. (2) The document reading device according to claim (1), wherein the delay means provides a time delay corresponding to a shift in reading positions of adjacent line sensors. (3) The document reading device according to claim (1), wherein the delay means is a storage means for storing an analog image signal output from the line sensor.