JPH0566062B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] Regarding a mid-stop/restart control method for a document reading device that is capable of automatic document feed (ADF) reading and flatbed type reading, it is possible to The purpose of this method is to provide an improved method that can reduce the disturbance of image seams compared to the previous method, and when stopping and restarting the document reading operation, the document feeding drive is through-down and the document is Then, move the carrier in the direction in which the document advances to a distance greater than the distance between the carrier and each stop position of the document, then move the carrier in the opposite direction to start reading from the document stop position, and then move the carrier to the document stop position. Then, move the carrier in the direction of document advance and stop at the normal carrier stop position. Next, move the document feed drive up in the direction of document advance, and start the normal carrier from the scanning end position. Control is performed to start reading after moving the distance to the stop position.

[Industrial application field]

The present invention relates to a mid-stop/restart control method for a document reading device that is capable of automatic document feeding (ADF) reading and flatbed type reading, and particularly relates to a mid-stop/restart control method for a document reading device that is capable of automatic document feeding (ADF) reading and flatbed type reading. The present invention relates to a reading control technology that prevents duplication or omission of image reading.

[Prior Art] FIG. 16 shows an example of a conventional document reading device having a structure that combines ADF reading and flatbed reading to which the present invention is applicable.

When performing ADF reading, the document is sucked in from the document suction section, read while feeding the internal document, and is ejected from the document discharge section. On the other hand, in the case of flatbed reading, the original is set on the flatbed section and read in a fixed state.

FIG. 17 shows a cross section of the mechanical part of the document reading device shown in FIG. 17 is a feed roller, 17 is a glass plate, 18 is a discharge roller, 19 is a carrier, and 20 is a lamp.

When performing the ADF reading described above, the set original 15 is moved between the pick roller 12 and the pick spring 1.
3, the paper is fed by the feed roller 16, the image is read when passing through the reading position, and the paper is discharged to the outside by the discharge roller 18. At this time, the carrier 19 is stopped at the reading position, and the light from the lamp 20 illuminates the surface of the original 15. The light reflected from the image on the document surface is then read by the CCD.

When performing flatbed reading, the original is placed on the glass plate 17, and the carrier 19 is moved in the horizontal direction to scan the original surface and read the image.

By the way, in order to store the scanned image data, the image reading device or the main device to which the image reading device is connected is provided with an image buffer, and this image buffer can store all the image data of the original. Usually, they do not have enough storage capacity.

In such a case, the method used is to wait until the image data is processed and the space becomes available before restarting.

However, in this way, the document reading stops midway,
When restarted, there was a problem in that due to the control characteristics of the mechanism, the original stopped too far, and the start was delayed, causing disturbances such as gaps in the image joints and degrading the image quality.

Conventionally, various measures have been taken to eliminate the disorder in the seams of images, including the following.

(1) Back and forward method When ADF reading is stopped midway, the document is moved back a predetermined amount when restarting, and then moved forward by a predetermined amount before starting reading.
This is to offset the amount of overshooting of the document when stopped midway and the delay time when starting.

Figure 18 shows the control characteristics of this method.
It can be seen from the figure that a delay in distance movement occurs during the period , and when stopping, the stop position overshoots during the through-down Q period. Therefore, when switching from midway stop to start, the delay time and overshoot amount are corrected by once moving backwards.

However, when the original is turned back, there is a drawback that, due to the structure of the mechanism, the original is easily wrinkled or torn at points A, B, and C in FIG.

(2) Reading method during slewing The rise and fall of the pulse motor is controlled using a slewing curve that minimizes hunting during document feeding and stopping operations. During the slewing, the drive signal of the pulse motor and the document reading signal are synchronized to read the document, thereby minimizing disturbances at the seam of the image. FIG. 19 shows an example of the control characteristics.

However, there are limits to the selection of the optimal slewing curve due to external disturbances such as the installation environment of the document reading device and paper feeding load, and it is difficult to reduce the delay time and overshoot amount to a sufficient degree. It was not possible to completely eliminate the disturbance.

[Problem to be solved by the invention]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved means for reducing image seam disturbances than conventional methods without backing up the document.

[Means to solve the problem]

The present invention provides a document reading device capable of automatic document feed (ADF) reading and fixed document reading, which controls the movement of a carrier when stopping and restarting the document during automatic document feed reading. As a result, it is possible to read a document with good image quality and less disturbance at seams without backing up the document itself.

The principle of the present invention will be explained with reference to FIG.

: When does the image buffer on the main unit become full?
When memory overflow is notified, data transfer is interrupted and the mid-stop restart control according to the present invention is activated. Thereby, the document movement is slowed down and the document movement is stopped. The document reading stop position at this time (represented as the document stop position in the figure; the same applies hereinafter) is located too far to the left of the normal carrier stop position (carrier position during automatic paper feeding reading operation). .

:Move the carrier in the direction of document advance beyond the document stop position by a sufficient distance necessary for stable operation.

: Move the carrier in the opposite direction beyond the predetermined reading end position by a sufficient distance necessary for stable document movement. At this time, the area from the original stopping position to the reading end position is read (indicated by a pre-reading area).

: Return the carrier to its original normal carrier stop position.

: The carrier moves up to resume moving the document in the forward direction, and the carrier resumes normal document reading from a point beyond the reading end position, that is, a point beyond the pre-reading area.

[Effect]

To explain the functions shown in Fig. 1, first, a stop request in the middle of reading a document is detected,
Accordingly, the document movement is temporarily stopped.

Now, in order to offset the hunting effect caused by moving the carrier, first move the carrier a sufficient distance in the direction of travel (this action is the same as moving the original backwards). Next, the carrier is moved in the opposite direction to compensate for the overshoot caused by hunting, and a certain area from the document stop position to the previous reading end position is read. This is to avoid reading in an unstable document movement state at the start-up when the document movement is restarted next time, by pre-reading with a carrier that is operating stably.

Next, return the carrier to its original stopping position,
to resume moving the original. At this time, the reading of the area read in advance is skipped, and only the area after the reading end position is read in a stable operating state.

[Embodiment] A first embodiment of the present invention will be described below with reference to FIGS. 2 to 15.

FIG. 2 is an explanatory diagram of control positions and moving distances according to an embodiment of the present invention, where D is a normal carrier stop position, E is a document stop position, H is a reading end position, and b
is the distance traveled by the document through-down control until it stops, and a is the extra distance necessary for stable operation of the carrier (if the carrier is moved at the same speed as the document feeding speed, the distance traveled by slewing is greater than the distance traveled by slewing) ), g is the distance a + b, j is the distance at which the paper feeding operation becomes stable, i is the distance from the reading end position H to the normal carrier stop position D, defined as i≧j, k is the distance traveled by the carrier through down.

Figure 3 shows each distance i, j, a,
This figure shows the relationship between b, k, the document and the carrier, and also shows the operation and reading signals of the corresponding document drive pulse motor and carrier drive pulse motor.

FIG. 4 shows the circuit configuration of one embodiment of the present invention, in which 1 is a control section, 2 is a mechanism section, 3 is an ADF motor driver for driving a document, 4 is an ADF motor, and 5 is a circuit diagram of an embodiment of the present invention.
6 is a paper feeding section consisting of mechanisms such as rollers and belts.
is a carrier motor driver for carrier drive, 7
8 is a carrier motor, 8 is a moving reading section including the carrier, and 9 is an amplifier for amplifying the read signal.
The ADF motor 4 and the carrier motor 7 are composed of pulse motors.

FIG. 5 will be used in the description of the subsequent examples.
The correspondence between the number of pulses for driving the ADF motor and the carrier motor and each distance described above in FIG. 2 is shown.

Fig. 6 shows the configuration of the carrier, in which 20 is a lamp, 21 and 22 are reflectors, and 23 is a lamp.
This is the light receiving part of CCD etc. The moving direction of this carrier is A in the same direction as the original moving direction, and B in the opposite direction.
It is expressed as

Figure 7 shows the flow of the processing procedure of one embodiment of the present invention, and Figures 2 to 6 can be used as necessary.
Reference is made to the figure.

In FIG. 7, when the automatic paper feed reading operation is started, the ADF motor is driven, the carrier motor is stopped, and the carrier is at the normal carrier stop position. In this state, document reading continues as long as data can be transferred to the main device.

When a signal indicating that the buffer is full is sent from the main unit, the reading operation is terminated, the ADF motor is slew-down by the number of pulses β, and the document is advanced by a distance b and then stopped.

Next, the carrier motor is driven in the A direction by a specified number of pulses α, the carrier is moved by h, and then stopped.

Next, move the carrier motor in the B direction for the specified number of pulses α.
-β is driven, and when α-β is reached, reading is started. Further, the reading is completed by driving in the B direction by a specified number of pulses β+γ. However, the carrier motor is further slewd down by the number of pulses η,
Stop.

Next, the carrier motor is driven in the A direction by η+γ, and the carrier motor is stopped.

Next, move the ADF motor in the A direction with the specified number of pulses γ.
Only drive and return to initial normal operation.

The above operation indicates a case where slewing is necessary when starting up the motor to stabilize torque or operation, but if self-starting is sufficient, b
indicates the amount of overshooting of the document during self-starting, and k indicates the amount of overshooting of the carrier during self-starting.

Furthermore, although the above-mentioned embodiment is based on the assumption that the number of pulses corresponds to the moving distance, the normal carrier stop position of the carrier may shift due to accumulation of errors, so the carrier stop position as shown in FIGS. By employing a positioning method using markings, reading accuracy can be improved.

Figure 8 shows an example (part 1) of the alignment method, in which markings are placed on the platen glass in a location outside the reading range in the main scanning direction, and this marking position is set to D in Figure 2. Match. By detecting this marking and stopping the carrier when it stops, it is possible to improve accuracy.

Figure 9 shows the markings in Figure 8 viewed from the side, and Figures 10 and 11 show the flow of the second embodiment, including carrier alignment using these markings. be.

The flow of a in Figure 10 is to move the carrier motor to A.
Detect the end of the marking in Figure 9 from the right, then continue to drive the carrier motor for the number of σ pulses and stop, then drive the carrier motor in the B direction for the number of σ pulses. Indicates an action to stop. Also, the flow of b is to move the carrier motor to B.
When the end of the marking is detected by driving in the same direction, the operation is shown in which the marking is further driven in the same direction by a specified number of pulses γ.

FIG. 11 shows a flow of a second embodiment in which the flows of FIGS. 10a and 10b are combined with the first embodiment of FIG.

Figure 12 shows the position D according to the markings in Figure 8.
This mark is an example (part 2) of an alignment method in which positioning is performed at ends I and H, and is composed of two marks divided in the sub-scanning direction.

FIGS. 13 and 14 are flowcharts of a third embodiment that performs alignment control based on the marks in FIG. 12.

FIG. 13c shows an operation in which the carrier motor is driven in the direction A, and when the end I of the marking is detected, it is driven down and stopped.

d in FIG. 13 shows an operation in which the carrier motor is driven in the direction B, and when the end I of the marking is detected, the carrier motor is further driven by a prescribed number of pulses φ.

FIG. 13e shows an operation in which the carrier motor is driven in the B direction, and when the end H of the marking is detected, the reading operation is completed, and the carrier motor is slewed down in the same direction and stopped.

FIG. 14 shows a flow of a third embodiment in which the flow a of FIG. 10 and the flows of FIGS. 13 c, d, and e are combined with the first embodiment of FIG. 7.

FIGS. 15a, 15b, and 15c show other examples of document alignment marks applicable to the present invention.

〔Effect of the invention〕

According to the present invention, it is possible to prevent damage caused by backing of a document as in the conventional method, and it is also possible to improve the image quality of the seam for slewing reading. In particular, even in a system where the image buffer has a small memory capacity and frequently stops midway, it is possible to read the original with good image quality.

[Brief explanation of the drawing]

Fig. 1 is a diagram of the principle of the present invention, Fig. 2 is an explanatory diagram of control positions and moving distances according to an embodiment of the present invention, Fig. 3 is an operation waveform diagram according to an embodiment of the present invention, and Fig. 4 is an embodiment of the present invention. Example circuit configuration diagram, FIG. 5 is a correspondence diagram of the number of pulses and distance used in explanation of the embodiment of the present invention, FIG. 6 is a diagram of the carrier embodiment configuration diagram, and FIG. 7 is the first embodiment of the present invention. 8 is an explanatory diagram of an example of the alignment method (part 1), FIG. 9 is an explanatory diagram of the operation of the alignment method (part 1), and FIGS.
FIG. 1 is a diagram showing the flow of the second embodiment, FIG. 12 is an explanatory diagram of an example of the alignment method (part 2),
13 and 14 are flowcharts of the third embodiment, FIG. 15 is a diagram showing an example of alignment marks on a document, FIG. 16 is an external view of an example of a conventional document reading device, and FIG. Figure 18 is a sectional view of the mechanism of a conventional document reading device, Figure 18 is an explanatory diagram of a conventional mid-stop restart method using back and force, and Figure 19 is an explanatory diagram of a conventional mid-stop restart system using reading during slewing. It is.

Claims (1)

[Claims] 1. An automatic paper feeding mechanism and a carrier, an automatic paper feeding reading function and a document fixed reading function, and the automatic paper feeding reading operation moves the automatically fed original to a normal stopping position. In a document reading device that performs reading by a carrier located at Move the carrier in the direction of document advancement to a distance greater than the distance between the carrier and each stop position of the document, then move the carrier in the opposite direction to start reading from the document stop position, stop after reading to the end position, and then The carrier was moved in the direction of document advancement and stopped at the normal carrier stop position, and then the document feed drive was moved up in the direction of document advancement and moved the distance from the scanning end position to the normal carrier stop position. A mid-stop restart control method for a document reading device characterized by starting post-reading.