JPH054367Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image scanner that reads information such as characters and figures written on a manuscript and outputs it as a hard copy using a printer.

[Conventional technology]

An image scanner reflects light from a light source onto a document, enters this reflected light into an image sensor such as a solid-state image sensor such as a CCD, and performs photoelectric conversion for each pixel forming the image sensor. By processing this data with a data processing means such as a personal computer, it is now possible to display it as a CRT image, hard copy, or the like. Here, the data sent from the above-mentioned image sensor to the data processing means is read out for each pixel in the image sensor, and in order to perform this reading, an image sensor drive control means is provided, and this image sensor drive control means is provided. The data of each pixel is sequentially read out by the scanning start signal and shift pulse transmitted from the means, binarized, and input to the data processing means, but since this read data is a continuous high and low level signal, In order to convert this signal into data for each pixel, a start signal and a clock signal for each scanning line are input from the image sensor drive control means to the data processing means, and based on these signals, the data processing means , it is now possible to convert each pixel into data.

[Problem that the invention attempts to solve]

By the way, the pixel density in the image scanner mentioned above is determined according to the number of pixels in the image sensor, and on the other hand, when displaying the document information converted into data by the image scanner as a hard copy, the printer If the dot density does not match the above-mentioned pixel density, the information on the document cannot be printed at the same size. For example, if the pixel density of the image scanner is 8 dots/mm and the dot density of the printer is 180 dots/inch (7.09 dots/mm), and if you print the original information as is, it will be 512 ÷ 7.09 mm, or 64mm square image
There is an inconvenience that the image is enlarged to 72mm square and output.

In order to improve this inconvenience, the applicant proposed in Utility Application No. 1983-43405 that a part of the clock signal is thinned out based on the mask signal output from the mask pulse generator. . According to this method, it is possible to adjust the pixel density of the image sensor and the dot density of the printer by appropriately adjusting the number of decimations of the clock signal by the mask signal, but it is not without problems.

That is, in the case of the prior application mentioned above, it is necessary to generate a mask signal having a pulse including one pulse of the clock signal using a mask pulse generator, so that the circuit cost for obtaining the desired duty ratio is reduced. In addition, because the tolerance for the pulse width of the mask signal is small, the clock signal may not be masked due to pulse width fluctuations or mask timing shifts. In some cases, undesirable masks were used.

Therefore, an object of the present invention is to provide an inexpensive image scanner that can reliably match the pixel density of an image sensor and the dot density of a printer by solving the problems of the prior art described above. .

[Means for solving problems]

In order to achieve the above object, the present invention includes an image sensor that reads information from a document, and a data processing means into which a signal from the image sensor is input, and the image data signal sent from the image sensor. , an image scanner that reads data for each pixel into the data processing means based on a scan start signal and a clock signal sent from a control means for controlling drive of the image sensor, the clock signal having the same period as the clock signal; pulse generating means for generating a reference pulse in which at least one edge is outside the pulse period of the clock signal; edge pulse output means for detecting an edge of the mask reference signal from the reference clock and the mask reference signal; mask signal output means for generating a pulse having a width of one period of the reference pulse from the reference pulse, and the mask signal is input from the control means to the data processing means based on the mask signal from the mask signal output means. This system is characterized by a structure in which a part of the clock signal is thinned out.

[Effect]

With the configuration described above, the masking is performed based on the reference clock having a sufficiently high frequency, one pulse edge of the mask reference signal, and a reference pulse having the same period as the clock signal and at least one pulse edge outside the pulse period of the clock signal. Since a signal is generated, the pixel density of the image sensor and the dot density of the printer can be adjusted by appropriately adjusting the number of decimations of the clock signal using this mask signal. Since this mask signal has a pulse having a period width of one period of the reference pulse, the desired clock signal can be reliably thinned out regardless of the other pulse edge of the mask reference signal. This eliminates restrictions on the duty ratio of the mask signal, making it possible to reduce circuit costs, simplify adjustment, and stabilize mask operation.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

First, in FIG. 4, reference numeral 1 indicates an image scanner for reading information displayed on a document 2, and the image scanner 1 is connected to a data processing means 3 such as a personal computer, and
A printer 4 for printing the data of the document 2 read by the data processing means 3 via the image scanner 1 is connected to the data processing means 3 .

As shown in Figure 1, image scanner 1
has an image sensor 10 made of a solid-state image sensor such as a CCD, and irradiates illumination light from a light source such as a light emitting diode (LED) toward the document 2, and makes this reflected light enter the image sensor 10. Accordingly, photoelectric conversion is performed for each pixel constituting the image sensor 10.

An image sensor driving means 11 is connected to the image sensor 10. The image sensor driving means 11 includes an oscillator 12 and a clock pulse generator 13. The clock pulse generator 13 inputs a scan start signal, a shift pulse, and a reset signal to the image sensor 10, and based on these signals. Image sensor 1
The data of each pixel at 0 is read out sequentially,
The image data is amplified by the amplifier 14 and binarized by the binarization circuit 15 so that it becomes a high level and a low level with respect to a predetermined slice level, thereby outputting a signal related to the image data to the data processing means 3. It's getting old.

Further, a scan start signal and a clock signal corresponding to the shift pulse from the clock pulse generator 13 described above are input to the data processing means 3, and based on these signals, the image from the image sensor 10 described above is processed. The data is taken into the data processing means 3 as each pixel data.

Here, the clock signal from the aforementioned clock pulse generator 13 is not directly input to the data processing means 3, but is input to the data processing means 3 via the OR circuit 16.
That is, the OR circuit 16 is configured to receive the mask signal output from the mask signal generating means 17, and the mask signal generating means 17 is further supplied with the mask signal output from the aforementioned clock pulse generator 13. A reference pulse, a reference clock, and a mask reference signal output from the mask oscillator 18 are respectively inputted. and,
When the mask pulse of the mask signal mentioned above is input to the OR circuit 16, the clock pulse generator 1
Even if a pulse signal is output from 3, no clock signal is output to data processing means 3, and when this mask pulse is output, thinning is performed to invalidate the clock signal generated during that time. There is.

FIG. 2 is a circuit diagram of the mask signal generating means described above, and FIG. 3 is a timing chart thereof.The operation thereof will be explained below with reference to these figures.

As mentioned above, the mask reference signal _M1 is generated from the mask oscillator 18, and the number of pulses corresponding to the difference between the pixel density of the image sensor 10 and the dot density of the printer 4 in one scanning line is emitted over a predetermined period of time. It is set to occur at intervals. On the other hand, the reference clock C ₁ and the reference pulse C ₂ are generated together with the clock signal from a single oscillator 12, and as shown in FIG. 3, the frequency of the reference clock C ₁ is sufficiently high, and the reference pulse C ₂
is set to have the same period as the clock signal and at least one pulse edge is outside the pulse period of the clock signal, that is, there is one pulse of the clock signal within one period of the reference pulse _C2 .

As shown in FIG. 2, an edge pulse _T1 is obtained from the NAND circuit 19 based on the mask reference signal _M1 and the reference clock _C1 . This edge pulse _T1 detects the rising edge of the mask reference signal _M1 , and based on the edge pulse _T1 and the reference pulse _C2 , it rises at the falling edge of the edge pulse _T1 , and the reference pulse C immediately after the edge pulse _T1 rises. A pulse signal Q that falls at the rising edge of ₂ is output from the flip-flop 20. Furthermore, based on this pulse signal Q and the reference pulse C ₂ , 1 of the reference pulse C ₂ is
A mask signal M having pulses with a periodic width is output from the flip-flop 21, and this mask signal M is input to the OR circuit 16 as described above. Therefore, by this OR circuit 16, the mask signal M
When the pulse of the mask signal is not input, the clock signal is output to the data processing means 3, but as shown at point A in FIG. 3, when the pulse of the mask signal is input, the clock signal is input to the OR circuit 16. Even if this happens, the clock signal will no longer be output. As a result, the clock signal is thinned out when the pulse of the mask signal M is generated, and
By reducing the number of effective pixels, it becomes possible to input data into the data processing means at a pixel density corresponding to the dot density of the printer 4.

For example, as described above, the image sensor 10
When using an image scanner 1 with a pixel density of 8 dots/mm and printing the data processed by this using a printer 4 with a pixel density of 180 dots/inch, the number of dots per 64 mm of the printer 4 is Since the number of pixels is 454 dots, 58 dots out of the 512 effective pixels outputted by the image scanner 1 are thinned out, and the mask reference signal _M1 of the mask oscillator 18 is set so that only 454 dots are valid. If the desired mask signal M is generated using the image data, it becomes possible to print at the original size. Furthermore, the number of mask pulses is not limited to the number mentioned above, but can be set to any number by changing it as appropriate. The range of compatibility becomes larger.

As is clear from the above explanation, in the above embodiment, the pulse width of the mask signal M is equal to that of the reference pulse.
Since the reference pulse C ₂ is set in advance so that one pulse of the clock signal is located within one period of the reference pulse C ₂ , a desired portion of the clock signal is detected by the mask signal M. You can definitely thin it out. In addition, the mask signal M is a mask reference signal
Since it is determined by one pulse edge of M ₁ and is unrelated to the other pulse edge of mask reference signal M ₁ , the mask reference signal
The pulse width of M ₁ can be widened, for example, with a duty ratio of 50%, and the cost of the mask oscillator 18 that generates the mask reference signal M ₁ can be reduced, the circuit adjustment can be simplified, and the mask operation can be improved. Stabilization can be achieved.

[Effect of idea]

As detailed above, the present invention generates a reference pulse having the same period as the clock signal and at least one edge of which is outside the pulse period of the clock signal, a reference clock having a sufficiently high frequency, and pulses at predetermined time intervals. A mask signal having a pulse having a period width of one period of the reference pulse is generated based on the mask reference signal, and the clock signal from the image scanner is thinned out by a predetermined number of pulses by the pulse of the mask signal and sent to the data processing means. Since the configuration is configured to input a simple rectangular wave as the mask reference signal, it is possible to reduce the cost of the oscillation circuit, simplify adjustment, and stabilize the mask operation. It becomes possible to provide an image scanner at a low cost that can reliably match the pixel density and the dot density of the printer.

[Brief explanation of the drawing]

The figures all relate to embodiments of the present invention; FIG. 1 is a circuit diagram of an image scanner, FIG. 2 is a circuit diagram of a mask signal generating means, FIG. 3 is a timing chart of output signals of the image scanner, and FIG. FIG. 4 is an explanatory diagram of the operating state of the image scanner. 1...Image scanner, 2...Manuscript, 3...
data processing means, 4... printer, 10... image sensor, 11... image sensor driving means,
12... Oscillator, 13... Clock pulse generator, 16... OR circuit, 17... Mask signal generation means, 18... Mask oscillator, 19... NAND
Circuit, 20, 21...Flip-flop.

Claims (1)

[Scope of utility model registration request] An image sensor that reads information from the document,
a data processing means to which a signal from the image sensor is input, and the image data signal sent from the image sensor, and a scan start signal and a clock signal sent from a control means for controlling the drive of the image sensor. In an image scanner that reads data for each pixel into the data processing means based on the clock signal, the image scanner generates a reference pulse having the same period as the clock signal and having at least one edge outside the pulse period of the clock signal. edge pulse output means for detecting an edge of the mask reference signal from the reference clock and the mask reference signal; and mask signal output means for generating a pulse having a width of one period of the reference pulse from the edge pulse and the reference pulse. 1. An image scanner comprising: a part of the clock signal inputted from the control means to the data processing means based on a mask signal from the mask signal output means.