JPS58205369A - Picture reader - Google Patents

Abstract

PURPOSE:To set the reading start position of an original arbitrarily, by providing a counter counting a clock pulse of a picture reader and providing a set means setting the count value of this counter arbitrarily. CONSTITUTION:A reading element 1 reads a picture of one-line's share at the same time with sequential scanning at each line and outputs a reading signal sequentially in synchronizing with a clock pulse from a timing generating circuit 2. The clock pulse from the timing pulse generating circuit 2 is counted at a counter 5, and a flip-flop 7 is set when the count value set at a switch 6 is counted and a line start pulse from the timing generating circuit 2 is applied to the reading element 1. Further, the reading start position of the original is set arbitrarily by setting the count value of the counter 5 with the switch 6 arbitrarily.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image reading device, and more specifically to a CCD
('Charge Coupled Device
This invention relates to an image reading device that reads an image by sequentially scanning each line using a method such as 'C'.

Conventionally, image reading devices have been known that use the above-mentioned COD or the like to sequentially scan and read images line by line.
Used in facsimile machines, etc. In this type of image reading device, when reading a document, the reading start position of the document is adjusted by adjusting the mechanical mounting position of the reading element. For this reason, complex adjustments and special external jigs are required at the assembly stage of the image reading device.Furthermore, to be able to adjust the reading start position, the reading element must be made movable, and the etc., there was a drawback that various considerations were required, such as setting the range of movement.

The present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional art, and provides an image reading device configured such that the image reading start position can be arbitrarily set without making the reading element movable. is intended to provide.

In order to achieve the above object, the present invention provides a counter that counts clock pulses of an image reading device that outputs an image reading signal bit by bit from a cell at one end of a reading element in synchronization with a clock pulse. A structure in which the image reading start position can be arbitrarily adjusted by providing a setting means that can arbitrarily set the count value of , and setting the number of clock pulses corresponding to the image reading start position. It was adopted.

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

FIG. 1 is a block circuit diagram illustrating an embodiment of the present invention. In the figure, the reference numeral 1 is an image reading element, and the CC
It is composed of elements such as D that scan one line simultaneously and optically read an image. The reference numeral 2 is a timing generation circuit, which generates a clock pulse 3 for outputting an image reading signal bit by bit from one end of the many cells that make up the image reading element, and a line '' indicating the start of one line of the image. A start pulse 4 is generated to inform the reading element 1 of the reading timing and reading start time. 5 is a counter that is initialized by line start pulse 4 and
This is a counter that counts 3 clock pulses. Reference numeral 6 indicates a count value setting means, which is exemplified as a switch for setting the count value of the counter 5, and sets the overflow value of the counter 5.

The counter 5 is connected to a flip-flop 7, which stores the overflow value of the counter 5.

Still, what is indicated by the symbol 8 is the image output of the reading element 1, which is 1
The pixel output is output in synchronization with clock pulse 3.

Also, what is indicated by the symbol 9 is the output of the flip-flop 7,
This serves as a signal to recognize the beginning of the image.

Next, the operation of this embodiment configured as described above will be explained with reference to the timing chart shown in FIG.

As mentioned above, the reading element 1 is composed of a reading element such as a CCD, and reads and stores one line of an image at the same time, and outputs the output from the timing generating circuit 2 as shown in FIG.
In synchronization with the line start pulse 4 shown in a) and the clock pulse 3 shown in FIG. I will do it.

Now, when it is desired to set the next bit from the end of a large number of arranged reading elements as the reading start position of the image, that is, the beginning, the value of A is set by the count setting means shown as switch 6.

If the value of 4tA is a positive value, the counter 5
If you set the value of λ, you can use a down counter. Conversely, if you set the value of λ, you can use an up counter as counter 5. In any case, if you count only A clock pulses, counter 5 will overflow. , a carry is issued as shown in FIG. 2(C), and as is clear from FIG. A carry signal is output, a flip-flop is set in synchronization with the fall of the carry signal, and image reading is started.

After the reading of one line is completed, reading of the next line is started again, and in this case, a line start pulse is also output. The flip-flop 7 is cleared by the rise of this line start pulse, and the flip-flop 7 is set again by the fall of the carry output of the counter 5, which occurs when A clock pulses are counted again, and the next line is read. will be started.

Since the number of cells in the reading element 1, which is made up of a CCD or the like, is known in advance, if the image reading start position is made to coincide with a certain reference point, for example, the edge of the document, with the farthest cell of the image reading element, The distance from the edge of the document at which reading should be started can be determined by counting the clock pulses after the line start signal is output. In other words, the number of clock pulses corresponds to the number of cells in the reading element, and if this can be set using the switch 6, which is the setting means, the image reading start position, that is, the beginning of the image, can be set arbitrarily. can be determined.

By the way, the switch 6 shown in the above-described embodiment may be replaced with an input/output port of a microcomputer, and the setting value may be made variable based on other information.

Additionally, the image reading start position can be set arbitrarily without fixing the mounting position of the image reading element and the image reading start position as constants of the device, making it extremely easy to locate the beginning of the document. . However, since the beginning of the document can be determined in bit units, the beginning position can be determined with extremely high precision, and the drawbacks such as degrading the quality of the image when reading shadows at the edges of the document are eliminated.

As is clear from the above description, according to the present invention, the number of clock pulses of an image reading device that scans one line sequentially to simultaneously read one line of images and sequentially outputs reading signals in synchronization with clock pulses. Since the structure is equipped with a counter that counts , and a setting means that can arbitrarily set the count value of the counter, the number of clock pulses that reverberate at the image reading start position can be set as the count value of the counter. This allows you to set the reading start position of the document at your discretion, and allows you to position the beginning of the document with extreme accuracy without requiring a mechanically complex mechanism to move the reading element. You can get excellent results by doing this.

[Brief explanation of the drawing]

FIG. DESCRIPTION OF SYMBOLS 1... Reading element, 2... Timing generation circuit, 3.
...Clock pulse, 4...Line start pulse,
5...Counter, 6...Switch, 7...Flip 70 knobs.

Claims (1)

[Claims] In an image reading device using an image reading element that reads an image scanned line by line and sequentially outputs an image reading signal in synchronization with a clock pulse, a counter for counting the clock pulses is provided, and a counter for counting the clock pulses is provided. A configuration is provided in which a setting means that can arbitrarily set a count value is provided, and the image reading start position can be arbitrarily set by setting the clock pulse count value according to the reading start position. Characteristic image reading device.