JPS6313627B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image information output device used in optical character reading devices, facsimile devices, and the like.

[Technical background of the invention and its problems]

As a scanning method for image processing devices such as optical character reading devices (hereinafter referred to as OCR) and facsimiles,
A combination of main scanning by a CCD line scanner and sub-scanning of the medium to be read is often used. As a drive source for sub-scanning, a step motor capable of open-loop control is widely used. In such a device, when processing or transmitting an image after scanning, it may be necessary to immediately stop scanning depending on the content of the image. For example, in facsimile transmission, if there are many points of change between black and white in an image, the information compression rate will be poor and scanning of the next line will be stopped for transmission.
In addition, in OCR, once line detection is completed, subsequent scanning does not start until the recognition of the line buffer in which already scanned data is stored is completed, and scanning is stopped/scanned for this purpose. The restart is
This happens many times during the processing of a single document/document.

On the other hand, a CCD line scanner consists of a light receiving section that integrates reflected light from a document or document, and an analog shift register that outputs the optically integrated voltage. Therefore, the current output signal is based on the optically integrated reflected light from one scan before. Also, the step motor used as a drive source ensures that a drive step (which is generally synchronized with the scan pulse) will cause a displacement of a predetermined step angle (i.e., step distance). However, since the motor is subject to load inertia and load torque during transport and scanning of documents and documents, a time lag occurs between the drive step and the actual step. For this reason, there is a problem in that images around the area where scanning is stopped and scanning is restarted are likely to be disturbed.

This will be specifically explained using FIG. 1 and FIGS. 2A and 2B. The step motor 1 scans and moves the form 3 using a drive system 2, and the pattern on the form is scanned by a lens 4.
The pattern is imaged on a CCD line scanner 5 and extracted. Various clock signals are generated from clock circuit 10. 11 is a control unit that controls the entire device; 12
is an amplifier that amplifies the output of line scanner 5, 1
3 is an image transfer control section including an A/D converter that converts the output of the amplifier 12 into analog/digital (A/D). The step motor control section 14 receives a drive signal from the control section 11 and has a function of providing a drive phase to the motor 1 from the motor drive circuit 15. In addition, in Figure 1 and Figure 2 A, 20
is a main scanning synchronization pulse signal, 21 is a drive step mask signal, 22 is a drive step synchronization signal, 23,
23' is a drive step request signal, 24 is a 4-phase A,
Step phase signals B, C, and D, and 25 are image transfer signals. Also, the signal P in Fig. 2 is the CCD
This is the optical integrated signal to the line scanner. Each time the drive step request signal 23 is applied, step phase signals A to D are output, and the step motor 1 is driven in steps. Drive step request signal 23 from the receiver side in response to drive step synchronization signal 22
When is not input, the step phase signal 24 does not change,
The motor 11 remains in the same phase and enters a stop operation. Assume that the pulse motor 1 is stopped in the A phase as shown in FIG. 2A. At this time, the motor control section 14 changes the drive step mask signal 21, which was at a high level when the motor was rotating, to a low level. Upon receiving the mask signal 21 that has become low level, the control section 11 stops outputting the drive step synchronization signal 22. Then, for example, after the TW time, the motor control section 14 again sets the drive step mask signal 21 to a high level, thereby making the step operation possible again. Then, in response to the drive step synchronization signal 22 output from the control unit 11 to the image data receiving device,
The drive step request signal 23 output from the receiving device side is inputted again, and the step phase signal 24 is outputted again. As a result, the step drive of the step motor 1 is restarted.

FIG. 2B corresponds to the timing chart of FIG. 2A, and shows the movement position relationship due to step drive of the motor 1. In FIG. 2B, the dash-dotted line shows the case where the step phase signal 24 is ideally followed, and the solid line shows the actual case. In addition, in FIGS. 2A and 2B, . . . respectively indicate photoelectric conversion patterns for one scan before one scan of the CCD line scanner 5. That is,
For example, the pattern shows a pattern obtained by integrating light between the B and C phases, and the pattern shows a pattern obtained by integrating light between the C and D phases.

As shown in FIG. 2A, the pulse in the step request signal 23 sent from the receiving device side
Image patterns corresponding to one scan before one scan in the optical integral signal P are sequentially output as an image transfer signal 25. In the case of FIG. 2A, the transfer pattern in the image transfer signal 25 is
, , , , etc. At this time, as shown by the solid line in Figure 2B, the pattern →,
If the movement is followed at a constant speed like →, →, the displacement amount will be the same as the step command. However, when there is a stop and restart as in pattern →, there is a shift of one scan between the pattern in the optical integral signal P and the corresponding output pattern in the image transfer signal 25, and In pattern →, the amount of movement is small because of the time delay until the movement start tracking. For this reason,
In the pattern output in the image transfer signal 25, the original pattern is almost faithfully reproduced in →, →, and →, but in → the pattern is omitted, and in → the pattern tends to overlap.
As described above, there has been a problem in the past in that the reproduced image tends to be distorted.

[Purpose of the invention]

This invention was made in view of the above circumstances, and eliminates disturbances in the photoelectrically converted image pattern when stopping and restarting step drive, and enables photoelectric conversion that is faithful to the original pattern for processing in the next stage. An object of the present invention is to provide an image information output device that can transfer a pattern that has been created.

[Summary of the invention]

In this invention, main scanning is performed by a line scanner, sub-scanning is performed by relative movement between the document and the line scanner using a step motor, and a step request signal is output in response to a step synchronization signal output to a receiving device. In a device that synchronously transfers an image pattern for one main scan that has been photoelectrically converted by the above-mentioned line scanner, when starting step drive, step drive is performed to a plurality of progressive phases for one step phase output, and a predetermined The transfer of the image pattern is suppressed until the step drive phase is reached, and when the step drive is stopped, the advance phase is controlled to be returned by a predetermined number, thereby preventing disturbance of the image pattern when the step drive is started and stopped. This is how it was done.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 3 shows a schematic configuration of an embodiment of the present invention, which includes the motor 1, drive system 2, form 3, lens 4, and line scanner 5 shown in FIG. 1, although not shown. Further, in FIG. 3, the same parts as the constituent elements shown in FIG. 1 are given the same reference numerals, and the explanation thereof will be omitted. In the figure, reference numeral 30 denotes a control unit which has a function of controlling the entire apparatus. Reference numeral 31 denotes a motor control unit which supplies step phase signals 26 of four phases A, B, C, and D to the motor drive circuit 15.
It also has the function of controlling the timer circuit 32. The timer circuit 32 is supplied with a clock signal from the clock circuit 10.
This circuit generates various signals for drive control of the step motor 1. Furthermore, signal 2 in Fig. 3
0 to 25 are signals having the same meaning as the signals shown in FIG.

Next, the operation of the above embodiment will be explained using FIGS. 4A and 4B. In FIG. 4A, T _I is the time of one cycle of the main scanning synchronizing pulse signal 20, T _W1 is the time to suppress the image pattern transfer output until a stable stop when the step is stopped, and T _W2 is the time at the start of the step. T d is the time to suppress invalid image pattern transfer output, T _d is the time until reverse step phase output (details for stable stop at step stop will be described later), and T _S is the output of step phase signal after step start. It shows the time required to generate a phase difference with the output of the main scanning synchronizing pulse signal. Among the above-mentioned times, the T _W1 , T _W2 , T _d , and T _S times excluding T _I are all determined by the timer circuit 32. That is, the motor control section 3 is connected to the timer circuit 31.
1 writes count value data and notifies the motor control section 31 of the end point of the count, thereby making it possible to determine the above-mentioned time.

As explained in the technical background of the invention,
The CCD line scanner 5 scans at a constant time period of T _I in the main scanning synchronization pulse signal 20, and
The step motor 1 performs step drive in synchronization with the scanning period pulse signal 20. However, in the step motor 1, there is a time delay even when the drive phase is applied due to the load inertia torque. On the other hand, even if driving is started from a stopped state, the output image after restarting is the image in the stopped state. In Figure 4 A, A
The signal 21 is set to high level again after T _W1 time, and when the image transfer is restarted, the image output and transferred is 〓. Therefore, unless the next output image is in a period in which it is moving around the B phase, disturbances will occur in the image. In other words, the image 〓 is followed by the image 〓
It is necessary to In order to perform this operation, the phase switching timing for performing the step drive is determined by changing the T _S time at the start of the drive step request signals 23 and 23' from the receiving device, as shown in the step phase signal 26 in FIG. 4B. set a delay,
Shift the scanning and phase of line scanner 5, and then
Step drive of the step motor 1 is performed at a period of T _I (a period of T _I of the main scanning period pulse signal 20). When this is done, the actual moving operation changes as shown in FIG. 4B.

On the other hand, since the phase is shifted in this way (delayed in this embodiment), an invalid image pattern occurs in the output image pattern from the CCD line scanner 5. (In this embodiment, 〓 is an invalid pattern.) Since the image to be transferred is valid when there is a response of the drive step request signal 23 to the drive step synchronization signal 22, the drive step mask signal 21 is again set to the low level period. T _W2 is provided, the output of the drive step request signal 22 is stopped, the response of the drive step request signal 23 is forcibly suppressed, and the actual movement has progressed by the number of required steps (“1” in this embodiment). Drive step request signal 23
to enable the occurrence of That is, between the first pulse PL1 and the next pulse PL2 in the restart operation of the drive step request signal 23, the B-phase and C-phase step drives are performed in this case, as shown in the step phase signal 26 in FIG. 4A. Let's do it. By doing this, it is possible to invalidate the image that should be invalidated.

Further, as shown by the broken line in FIG. 4A, when the step drive is stopped because the drive step request signal 23 no longer responds to the drive step synchronization signal 22, As shown in the step phase signal 26, phase B, which is one step ahead of phase A, which should be stopped due to the phase shift, is given. For this reason, the motor control section 31
Then, the step phase signal 26 instructs to return to the A phase again, and stops at the A phase. In order to stabilize the stoppage of the motor 1, this reverse step phase output is set at Td from the timing of the pulse in the drive step synchronization signal 22 when the motor 1 is stopped.
It will be done after hours.

Note that the above-mentioned times T _S , T _d , T _W1 , and T _W2 can be determined experimentally. That is, in the above embodiment, one reverse step phase output is performed when the motor is stopped, and two preceding step phase outputs are performed when the motor is restarted, but the number of step phase outputs is not limited to this. By such an operation, the pattern 〓, 〓, 〓, 〓, 〓, 〓, . . . appears in the image transfer signal 25 output from the image transfer control section 13 in this order. Note that the pattern 〓 is centered on the C phase, and the pattern 〓 is centered on the D phase.
The image is centered on the phase, 〓 is centered on the A phase, 〓 is centered on the B phase, etc., and it is possible to transfer an image without missing or overlapping images and without any disturbance as in the conventional method.

〔Effect of the invention〕

As described above, according to the present invention, since the phase difference between the step drive timing and the main scanning timing is used, it can be constructed at low cost, and there is no disturbance in the photoelectrically converted image, and the original pattern is It is possible to transfer image patterns that are faithfully reproduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a conventional example, FIGS. 2A and B are diagrams for explaining the operation of the conventional example in FIG. 1, respectively, and FIG. 3 is a schematic configuration diagram of an embodiment of the present invention. 4A and 4B are diagrams for explaining the operation of the embodiment shown in FIG. 3, respectively. 1...Step motor, 5...Line scanner, 1
0... Clock circuit, 13... Image transfer control section, 30
...Control unit, 31...Motor control unit, 32...Timer circuit.

Claims (1)

[Claims] 1. A line scanner that main-scans a form on which image information is recorded and outputs a photoelectric conversion signal, and digitizes the photoelectric conversion signal for one scan output from this line scanner and sends the image information to an external image information receiving means. a step motor for moving the form to perform sub-scanning of the form; a step motor control means for exciting the step motor and controlling its rotational drive; It outputs a drive step synchronization signal indicating a transferable state to the receiving means, and receives a drive step request signal indicating a scanning request output from the image information receiving means in response to this drive step synchronization signal. In response to the request signal, the step motor control means is controlled to cause the step motor to move the form to the next sub-scanning position, and to transfer the image information at the previous sub-scanning position to the image information transfer means. control means for causing an output to the information transfer means, and when the control means stops receiving the drive step request signal during continuous scanning, the control means reversely rotates the step motor by a predetermined sub-scanning position to move the form. Then, when the drive step request signal is received and scanning is resumed, the step motor is rotated in the forward direction by a predetermined sub-scanning position to move the form and move the form to a predetermined sub-scanning position. An image information output device characterized by controlling the transfer of the image information to be suppressed until the image information reaches a scanning position.