JPH0460386B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention includes an illumination device that illuminates the surface of a document, and a linear image sensor that converts image information of the document into an electrical signal. The present invention relates to an image input device that moves the linear image sensor in a direction perpendicular to the main scanning direction and inputs electrical signals related to an image of a certain area on a document surface to a printer, magnetic recording device, display device, computer, etc.

(Background of the Invention) In such an apparatus, it is often necessary to externally set the main scanning range of the linear image sensor and arbitrarily adjust the input area of the document in the main scanning direction. Therefore, one possible method is to change the pulse width of the one-shot multivibrator by changing the resistance value of a potentiometer that is linked to the adjustment means, and allow the signal from the image sensor to pass through to the next stage only during the period when the pulse is being output. The potentiometer is easily affected by resistance value errors, variations, and temperature changes, and since the potentiometer's resistance value is time-converted using a monostable multivibrator, there is a risk of leakage from the capacitor used there. The drawback was that it was susceptible to temperature changes.

(Object of the Invention) An object of the present invention is to improve this drawback and provide a stable scanning width setting device for an image input device that is not easily affected by environmental changes such as temperature or noise.

(Embodiment) FIG. 1 is an external view of an embodiment in which the present invention is applied to a simple copying device. Place the main unit 2 on top of the original 1 as shown in the figure, and manually move the entire device in the direction of arrow A while pressing the push button switch SW with your finger.The image input device built into the main unit 2 will read the image information of the original. is converted into an electrical signal (image signal),
It is also sent to the printer built into main unit 2. Since the printer prints an image corresponding to this image signal on the paper 11 as it is, the image of the portion where the main body 2 moves on the original document is copied as is on the paper 11. There is a scanning width setting knob 9 at the bottom of the main body, and by moving this in the direction of arrow B and setting the index 10 to a desired position on the document, the copy width in the direction of arrow B can be adjusted as desired. I can do it.

FIG. 2 is a diagram showing the internal configuration of the image input device portion of the embodiment shown in FIG. 1. 3 is for lighting
The LED array illuminates a narrow band-shaped area on the original 1 that is read by the linear image sensor 5. The image of this part of the document is formed by the imaging lens 4 on the image receiving surface of the linear image sensor 5. 6 and 7 are rollers for guiding the movement of the main body 2, and one of them 6 has a radial conductive pattern 12. Together with the brush 8 in contact with the brush 8, it constitutes a contact type encoder, and converts the amount of movement of the main body 2 in the direction of arrow A (hereinafter referred to as the sub-scanning direction) into the number of pulses.

The above-mentioned indicator 10 and brush 13 are fixed to the scanning width setting knob 9, and the brush 13 is attached to the code plate 1.
4 Slide on the top. On the code plate 14, as shown in FIG.
Six rows of conductor patterns e and 14f are provided, and each of these conductor patterns has contact pieces 13a, 13b, 13c, 13d, 13e, 1 of the brush 13 shown in FIG.
3f are in corresponding contact. Therefore, if the contact terminal Tf is connected to the voltage corresponding to the high level of the logic circuit (for example, the positive side of the power supply), the terminals Ta, Tb, Tc, Td, and Te of the code plate 14 are connected to the brush 13 position. A corresponding 5-bit so-called Gray code digital signal is output.

The width indicated by the arrow W in FIG. 2 is the maximum scanning width determined by the size of the linear image sensor 5 and the subsequent image signal processing system. An example is shown in which it is limited to W′.

FIG. 5 shows a block diagram of a circuit according to an embodiment of the present invention. Linear image sensor 5 is shown here.
I'm using an OCD type of thing. This is driven by a pulse sent from the sensor drive circuit 101, which includes a charge corresponding to the light intensity stored in the photoelectric conversion section of the CCD linear image sensor, which is transferred to the shift register section in the same sensor. Transfer pulse _T is added to the shift register section and sent to the adjacent cell in the order of charge,
Finally, there are two-phase clock pulses ₁ and ₂ to reach the output gate in the same sensor, and a reset pulse _R to reset the output gate every time one pixel is read out. _T is one pulse that is output just before each main scan, and then ₁ ,
₂ and _R are added in a fixed phase relationship, and the signals are sequentially sent to the output terminal of the sensor. At this time, ₁ and
₂ are pulses with opposite phases to each other, and one pulse is output every time two pixels are read out, and _R is output at a rate of one pulse every time one pixel is read out. The output of the linear image sensor 5 is converted by a binarization circuit 102 into a voltage that takes either a high level voltage for white and a low level voltage for black, and is applied to an OR gate circuit 103. The output of this OR gate circuit 103 is temporarily stored in a memory circuit 104, read out again, and applied to a thermal head 106 via a thermal head drive circuit 105 to print an image on paper 11 in accordance with the signal.

On the other hand, the gray code digital signal obtained from the code plate 14 is applied to a decoder 107 and converted into an appropriate binary code, and then is sent to a counter 10.
8 parallel input terminals J ₁ , J ₂ , J ₃ , J ₄ , and J ₅ . This counter 108 is configured as a down counter that can be preset, and the sensor drive circuit 1 is connected to the preset enable terminal PE.
_T from 01, _R to clock input terminal CK,
The carry output terminal CO is connected to the clock input terminal CK of the D flip-flop circuit 109. This D
A high level voltage Vcc is applied to the D input terminal of the flip-flop circuit 109, and the clear terminal CL
_T is added from the sensor drive circuit 101 to .
Output terminal Q is connected to the other terminal of OR gate circuit 103.

Now, when the scanning width setting knob 9 is operated to set an arbitrary scanning width, the position of the brush 13 with respect to the code plate 14 is determined, and information on that position is sent as a gray code signal to the decoder 107, where it is is converted into a binary code, and the counter 10
8 parallel inputs _J1 to _J5 . At this time,
This parallel input is converted by the decoder into the following form. For example, if the pixel density of the linear image sensor 5 is 64 pixels per mm and the image magnification of the imaging optical system 4 is 1/4, the surface of the original 1 will be read at a density of 16 pixels per mm. If the set reading width W' is 10 mm, this corresponds to 160 pixels. Normally, the CCD linear image sensor 5 has an area called a dummy register or dummy sensor for 10 to 20 pixels before an effective signal is output. That is 160+12=172
Add as a binary code. In other words, the numerical value of <number of pixels corresponding to the set reading width> + <number of pixels required until a valid signal is output> is converted into a binary code and sent to the above-mentioned parallel inputs J1 to _J5.
In other words, it is added to

Next, when the main body 2 is moved in the direction of arrow A while pressing the switch SW, the circuit is activated, and the sensor drive circuit 101 outputs the drive pulse as described above. First, when the transfer pulse _T is issued,
Charge is transferred from the photoelectric conversion section to the shift register section within the linear image sensor 5, and the preset enable terminal PE of the counter 108 is
_T is added to the counter 108, and the counter 108 is preset to the value of the output of the decoder 107 (parallel input of 108). At the same time _{, T} is also applied to the clear terminal CL of the D flip-flop 109, and the D flip-flop 109 is cleared.
Therefore, the output Q of 109 becomes low level. Next 2
Phase clock pulses ₁ , ₂ and reset pulse _R
is output from the sensor drive circuit 101, and reading out the output of the CCD linear image sensor 5 begins.
After the output of the linear image sensor 5 is binarized by a binarization circuit 102, it passes through an OR gate circuit 103, is temporarily stored in a memory circuit 104 that serves as a buffer, and is read out again to the thermal head. It is added to the drive circuit 105 and drives the thermal head 106 to print the binarized image on the paper 11. At this time, each time a signal for one pixel is read out from the linear image sensor 5, a reset pulse _R is applied to the counter 108 for one pulse, and the preset counter is counted down as described above. When the pixels corresponding to the preset value are read out, the counter 108 becomes zero, a carry signal is output from the carry output terminal CO and applied to the clock terminal CK of the D flip-flop circuit 109, and the output Q of the D flip-flop circuit 109 becomes Change from low level to high level. Then, the output of the OR gate 103 becomes high level regardless of the signal from the binarization circuit 102, so from now on, the output of the OR gate 103 becomes high level.
A white signal will be sent to the circuits after 04. When all the pixels of the linear image sensor 5 have been read out, the transfer pulse _T is issued again and the above-described operation is repeated. In this way,
A configuration is possible in which a white signal is given to a signal exceeding the width W' set by the scanning width setting knob 9, regardless of the signal from the linear image sensor 5, and that part is not printed.

In this embodiment, the counter 1 is preset with information from the code plate 14 and the decoder 107.
08 is counted down by a pulse output from the sensor drive circuit 101 for each pixel, and when the contents of the counter 108 reach zero, a carry signal is applied to the D flip-flop circuit 109.
This is done by presetting a value corresponding to the complement of the number of pixels corresponding to the set scanning width W' in the counter 108, and counting up with a pulse output from the sensor drive circuit 101 for each pixel, until the counter 108 counts up to the maximum number. The structure may be such that a carry signal is sent to the D flip-flop circuit 109 when this happens.

(Effects of the Invention) With the configuration as described above, according to the present invention, it is possible to realize a stable scanning width setting device for an image input device with a simple configuration and less affected by environmental changes such as temperature and noise. can.

[Brief explanation of drawings]

Fig. 1 is an external view of an embodiment in which the present invention is applied to a simple copying device, Fig. 2 is a diagram showing the internal configuration of the embodiment shown in Fig. 1, and Fig. 3 constitutes a part of a position detection device. The code plate FIG. 4 is a brush constituting a part of the position detection device, and FIG. 5 is a circuit block diagram of an embodiment of the present invention. Explanation of symbols of main parts, 9... Scanning width setting knob, 10... Index, {13... Brush, 14...
code plate, 107... decoder} position detection device,
{108...Counter, 109...D flip-flop, 103...OR gate} Signal limiting circuit.

Claims (1)

[Claims] 1.Equipped with an illumination device that illuminates the document surface and a linear image sensor that converts grayscale information of the image of the document into an electrical signal, the entire device is moved along the document surface in a direction perpendicular to the main scanning direction of the linear image sensor. In an image input device that converts an image of a band-shaped area on a document into an electrical signal by moving the
an operating member for manually setting the range of main scanning by the linear image sensor from the outside; a position detecting device for outputting a digital electrical signal according to the position of the operating member; 1. A scanning width setting device for an image input device, comprising a signal limiting circuit that limits signals from a linear image sensor.