JPH02217836A - Image reader - Google Patents

Abstract

PURPOSE:To judge whether or not conditions where a step-out hardly occurs are adequate and to read an image only when the conditions are adequate by comparing the difference between the returning position of a scanner and a specific initial position by a 2nd comparing means as a result of a scan which is made under restricted conditions. CONSTITUTION:The image read scanner is scanned according to the restricted conditions and the 2nd comparing means compares the difference between the return position of the scanner after the scan is made under the restricted conditions and the specific initial position to judge whether the restricted conditions are conditions where an image read is not retarded. When the image read is not retarded under the restricted conditions, the image is read under the restricted conditions and when the image read is retarded, the image read is not made. Consequently, if a step-out is fine, the image can be read under the conditions where the step-out hardly occurs and it is confirmed whether the conditions where the step-out hardly occurs are adequate or not.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image reading device that reads a document while scanning the document by moving a scanner and the document relative to each other. The present invention relates to an image reading device that detects abnormalities in position.

[Prior Art] In a copying machine using a conventional image reading device, a scanner scans an original, forms an image on a photoreceptor drum, and transfers the image onto copy paper, thereby making a copy of the original. I am doing it.

Normally, a scanner has a predetermined initial position, and uses this position as a reference to read a document and synchronize with the supplied copy paper. Therefore, for the copying machine to operate properly, the scanner must always be set at the initial position before starting copying. In order to reliably set the scanner at the initial position, a home position sensor is usually provided to set the scanner at the initial position, and a stepping motor is used as the scanner motor. Particularly in a color copying machine using a field-sequential printing method, since multiple scans are performed for each color, registration alignment is important to match the edges of the images in each scan.

For this reason, a stepping motor is also used as a scanner motor. That is, a stepping motor is used and numerically controlled to ensure positioning.

However, tax adjustments may occur in stepping motors. Adjustment refers to the fact that the motor does not follow numerical control pulses sent from the controller. This tax adjustment mainly occurs in the following cases.

(1) There is a certain relationship between the rotational speed of the stepping motor and the load torque at that speed, but this occurs when the load torque exceeds the limit. Cases in which the load torque exceeds the limit are shown below (2) and (3).
Due to reasons such as.

(2) This problem occurs when dust gets into the slider of the stepping motor when the scanner motor is left in a dusty place for a long period of time.

(3) Normally, a scanner motor is moved along a rail fixed to a document table on which a document is placed. At this time,
When a heavy object is placed on the document table, the document table may bend. As a result, the rail of the scanner motor is bent, causing step-out.

When the above-mentioned tax adjustment occurs, the position of the scanner cannot be controlled and the scanner does not stop at a predetermined stop position.

[Problems to be Solved by the Invention] Since a conventional copying machine using a scanner is configured as described above, when a tax adjustment occurs on the scanner, the scanner does not stop at a predetermined position and other parts are damaged. There is a risk of a collision and destruction of the copying machine itself. To deal with this, conventionally, overrun sensors have been provided at both ends of the scanner in the movement direction to prevent the scanner from overrunning a predetermined movement range. Therefore, when the overrun sensor detects an overrun of the scanner, it is determined that the copying machine is in trouble with the tax adjustment, and subsequent copying operations are disabled. For this reason, there is a problem in that even if the tax adjustment is slight and there is no problem with copying if only the copying conditions are restricted, copying is impossible.

This invention was made to solve the above-mentioned problems.If the tax adjustment is small, image reading is possible under conditions where the tax adjustment is unlikely to occur, and where such conditions are unlikely to cause step-out. ``It is an object of the present invention to provide an image reading device that can determine whether or not an image is appropriate and can read an image only when the condition is appropriate.

[Means for Solving the Problems] An image reading device according to the present invention includes an image reading scanner that uses a stepping motor to read an image while scanning the original by reciprocating it relative to the original; The reading scanner starts scanning the document from a predetermined first initial position, returns to the second position after scanning, and
The scanning is performed under a plurality of conditions, the plurality of conditions are variable, and includes a first scanner position detection means for detecting a first difference between an initial position of ¥Sl and a second position; a first comparing means for comparing the difference between the first value and the second predetermined value; scanning condition constraining means for constraining the scanning condition to some of the plurality of conditions when it is determined that the value of a second scanner position detection means for detecting a second difference between and a third position; and a second comparison means for comparing the second difference with predetermined first and second values. and scanning stopping means for stopping scanning when the second comparing means determines that the second difference is larger than the first value.

[Operation] The image reading scanner of the present invention performs scanning under constraint conditions, and the second comparison means compares the difference between the return position of the scanner and a predetermined initial position as a result of the scan performed under constraint conditions. Then, based on the difference, it is determined whether the constraint conditions are such that they do not hinder image reading.

[Embodiments of the invention] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view showing the overall configuration of a digital color copying machine to which the present invention is applied.

This copying machine converts a document image read by an image sensor into image data, which is a digital signal, and prints (forms) an image on paper using an electrophotographic method in accordance with this image data.

Referring to FIG. 1, the digital color copying machine includes an image reading section 71 for reading an image of a document and processing the read image, and a laser beam for recording an image signal read by the image reading section 71. Scanning exposure unit 7 for converting into signals
2, and an image recording section 73 for copying the image of the original onto copy paper using the laser light output from the scanning exposure section 72.
including. The image reading unit 71 is provided with a document table 16 for placing a document and below the document table 16.
A scanner 10 includes an image sensor for reading an image of a document placed thereon, a scanner motor 11 for driving the scanner 10, a sensor 100 for detecting the home position of the scanner 10, and the scanner 10. It includes an overrun sensor 101 for detecting the position of the scanner 10 so as not to overrun the motor 11 side, and a signal processing section 20 for processing signals read by the scanner 10. The scanning exposure section 72 includes a printer head 31 for converting the signal processed by the signal processing section 20 into a laser beam for recording, and a reflecting mirror 37 for reflecting the laser beam. The image recording section 73 is provided with the photoreceptor drum 41 for forming an electrostatic latent image with a laser beam reflected by the reflecting mirror 37, and on the outer periphery of the photoreceptor drum 41, and for charging the photoreceptor drum 41. a charger 43, developing devices 45a to 45d for developing the electrostatic latent image on the photosensitive drum 41, and a photosensitive drum 4.
A transfer drum 51 for transferring the image on the copy paper 1, a fixing device 48 for fixing the image transferred to the copy paper by the transfer drum 51, and a paper sheet for holding the copy paper sent to the transfer drum 5. It includes a cassette 50 and a paper discharge tray 49 for holding copy sheets fixed by a fixing device 48.

The scanner 10 includes an exposure lamp 12 that irradiates the original, a rod lens array 13 that collects reflected light from the original, and
Close-contact COD for converting focused light into electrical signals
and a color image sensor 14 consisting of a color image sensor 14 and the like.

In this embodiment, an image reading device in which the document table is fixed and the scanner moves is shown, but the scanner may be fixed and the document table is moved. In this case, the document table is driven by a stepping motor.

Next, the operation of the digital color copying machine shown in FIG. 1 will be explained. The scanner 10 is driven by a motor 11 to scan the original on the original table 16 when reading the original image. Here, the moving direction of the scanner 10 (direction of the arrow in FIG. 1) is the scanning direction, and the direction in which the image sensors 14 are arranged (direction perpendicular to the plane of the paper in FIG. 1) is the main scanning direction.

The original image illuminated by the exposure lamp 12 is photoelectrically converted by the image sensor 14 and sent to the read signal processing section 20.
is converted into a print signal of yellow, magenta, cyan, or black.

In the printer head section 31, the LD drive circuit 33 is operated according to the print signal for each color from the signal processing section 20, and the semiconductor laser 34 blinks (see FIG. 2).

A laser beam generated from the semiconductor laser 34 is reflected by the reflecting mirror 37 and exposes the photosensitive drum 41. The surface of the photosensitive drum 41 is uniformly charged by a charging charger 43, and an electrostatic latent image is formed by receiving the above-described exposure.

This electrostatic latent image is developed into yellow, magenta, cyan, or black by any one of the developing devices 45a to 45d. The developed image is transferred by the transfer charger 46 onto a sheet of paper wrapped around the circumferential surface of the transfer drum 51. After the above-mentioned process is repeated for at least one color of yellow, magenta, cyan, or black, the paper is separated from the transfer drum 51 by the separation claw 47, fixed by the fixing device 48, and ejected to the paper ejection tray 49. It is papered. During these periods, the scanner 10 repeats the scanning operation in synchronization with the rotational operations of the photosensitive drum 41 and the transfer drum 51. The transfer drum 51 is provided with a position sensor 53, and is controlled to synchronize with the scanner 10 based on a detection signal from the position sensor 53. The diameter of this transfer drum 51 is larger than the diameter of the photosensitive drum 41. This is because large size paper can be set by wrapping it around the circumferential surface of the transfer drum 51. Of course, both diameters may be the same.

Note that the paper is fed from a paper cassette 50, and its leading edge is chucked by a chucking mechanism 52 provided on the transfer drum 51, so that no misalignment occurs during transfer of each color. Further, 42 is an eraser lamp.

FIG. 2 is a block diagram showing the configuration of the read signal processing section 20. As shown in FIG. The image signals of three colors, R (red), G (green), and B (blue) photoelectrically converted by the image sensor 14 are each operationally amplified by a log amplifier 21 into a signal having a size corresponding to the image density. Ru. The reason why the log amplifier 21 is provided here is as follows. COD
The image signal received from the original is proportional to the reflectance of the original.

Therefore, in order to convert this into an image signal, it is necessary to convert this into density. Generally, the logarithm of reflectance is proportional to density, so a log amplifier is used to convert the reflectance detected by the CCD into density. Next, it is converted into a digital signal by the A/D converter 22. This digital signal is an image signal (image data) having gradation, and is then subjected to shading correction by the shading correction circuit 23.

Next, the masking processing circuit 24 performs R and G.

Image signals (print signals) for printing corresponding to each print color of Y (yellow), M (magenta), C (cyan), and B (black) are generated from the image signals of the three colors of B by the developing device. It is generated according to the characteristics of toners 45a to 45d.

Note that the print signal for which color is generated depends on the CP.
It is determined sequentially by the control signal from U25. Further, the CPU 25 receives various key human power signals from an operation panel (not shown), and also receives a detection signal TBASE from a position sensor 53 provided on the transfer drum 51, and drives the scanner 10 based on this signal. A control signal for controlling the motor 11 is output from the CPU 25. Note that the CPU 25 also receives signals from a sensor 100 for detecting the home position of the scanner 10 and a sensor 101 for detecting overrun of the scanner.

Note that the sensor 100 functions as a home position sensor when the power is turned on, but is not turned on at other times (when the scanner 10 is scanning).

The subsequent electric magnification/variation movement circuit 26 performs a magnification operation in the irradiation direction and a movement operation in the movement direction. In addition, by repeatedly outputting the same area multiple times within the electric magnification/movement circuit 26, it is also possible to output multiple identical images in the operating direction.

The halftone processing circuit 27 binarizes the print signal from the masking processing circuit 24 by, for example, a dither method, and generates a binary pseudo halftone signal. The halftone-processed signal is input to the LD drive circuit 33 via the I/F circuit 18. The I/F circuit 28 has a line memory that stores image data line by line. This line memory has a capacity for two lines so that read and write operations can be performed in parallel. LD drive circuit 33
causes the semiconductor laser 34 to blink in response to this signal data. The beam generated by the semiconductor laser 34 is reflected #! as shown in FIG. The photoreceptor drum 41 is exposed through the photoreceptor 37. As a result, an image is drawn on the photoreceptor drum 41, and an electrostatic latent image is formed.

Next, scanner control of the digital color copying machine having the above configuration will be explained. In a digital color copying machine having a line memory but not a full screen memory as in this embodiment, it is necessary that the scanner 10 and the transfer drum 51 be driven in synchronization. In this embodiment, the photosensitive drum 41 and the transfer drum 51 rotate at a low speed, and the start-up of the scanning operation of the scanner 10 is controlled in accordance with the operation of the transfer drum, so that they are synchronized. Therefore, the rotation of the transfer drum 51 is detected by the position sensor 53 provided on the transfer drum 51, and this detection signal TBASE is input to the CPU 25. CPU2
Reference numeral 5 controls the motor 11 to drive the scanner 10 so that the leading edge of the original image can be read after a predetermined period of time has elapsed from the rise of the TBASE signal.

In this case, if the magnification in the sub-scanning direction changes, the scanner 10
The effective rise time of will vary accordingly. Therefore, it is necessary to adjust the start-up time of the scanner 10 by shifting the startup timing of the scanner 10 according to the magnification, or by shifting the 1° home position of the scanner itself, or by making a complex correction that combines the two. be.

FIG. 3A is a timing chart when the above correction is performed by shifting the home position of the scanner IO. Scanner 1 immediately starts at the rising edge of the TBASE signal.
0 is activated. The home position of the scanner 10, which is the starting position, differs depending on the magnification. For example, if the home position at 1x is H5, the home position Ho1 at 0.5x is quadrilateral AI AI/2 B+/2
The home position H2 at the time of doubling is a position B+ (distance expressed as time x speed) away from the image leading edge position, and the home position H2 at the time of doubling is a position closer to the image leading edge position by quadrilaterals A2A'', B, and B2 (see Figure 3B). Here, it goes without saying that the rise of the TBASE signal does not necessarily have to coincide with time 0, but may be before that time.By controlling the start of activation of the scanner 10 as described above, the magnification in the operating direction can be adjusted. Regardless, the scanning operation can be started for the leading edge of the original image after a certain period of time from the fall of the TBASE signal, and the print/read unit 31 starts printing at this point. The relationship with time is shown in Figure 4. In Figure 4, the X-axis represents time and the Y-axis represents speed. The negative range of the Y-axis also represents the negative direction of speed. Referring to the figure, the scanner 10, which has started up to a low scanning speed at time t, scans at a low speed the scanner length determined from the document size (until time t2).After scanning is completed (time ta), the scanner 10 immediately The scanner 10 is accelerated in the opposite direction (time t
, ~t,), returns to the home position at high speed (from time t to t6) and stops (time t7).

Next, specific control of the scanner of the digital color copying machine during tax adjustment will be explained with reference to a flowchart.

FIG. 5 is a flowchart showing the main routine of the process for detecting the tax adjustment status of the scanner of the digital color copying machine.

Referring to FIG. 5, when the power of the digital color copying machine is turned on, initialization of the scanner 10 is first performed to bring the scanner 10 into a document reading state (S102). Next, it is determined whether or not the print switch is on (S104), and if it is, a test scan (S106) is performed to determine whether the scanner 10 is in the document reading state, and the scan The operation starts (
S108). Next, abnormality detection 1 (SllO) detects whether the scanner 10 is in an overrun state, abnormality detection 2 (5112) determines whether the scanner 10 is started normally, and the actual copying operation is performed. Each process (5114) is performed. Note that if the print switch is not turned on in step 5104, the processing flow moves to abnormality detection 1 (S110). Copy operation (5114
) is completed, the trouble flag is checked to determine whether the scanner 10 is in trouble due to tax adjustment (S116), and if it is not in trouble (S
If YES in step 116), the end of the scan is determined (
311.8). If the scan has been completed (YES in S118), the processing flow is Pg!, which determines whether the print switch is on or not. The process moves to (S104). If the scan has not been completed in step 5118, the processing flow moves to abnormality detection 1 (5110). Note that when it is determined in step 5116 that there is a trouble state (NO in S116), it is determined whether the trouble state has been reset (5120).
. When the trouble state is reset in step 5120, the processing flow moves to the initialization subroutine (S102), and when the trouble state is not reset (S1
20), the process is stopped until the trouble condition is reset.

Next, details of each subroutine shown in FIG. 5 will be explained in order.

FIG. 6 is a flowchart showing details of the initialization subroutine shown in step 5102 of FIG.

The scanner 10 may not be at the home position when the digital color copying machine is powered on. Therefore, first, the operation of returning the scanner 10 to the home position is started. Here, the home position to be returned to is a position farther from the leading edge of the image than the scan start position at the minimum magnification (that is, when the scan speed is the fastest). This corresponds to the position marked H in Figure 3B. To achieve this kind of operation, scanner 1
The sensor 100 of the scanner 10 transmits a signal that becomes "Ho" when the position of the reading section 0 is at the above-mentioned HO or further from the front edge of the image, and "Ho when the position is closer to the front edge of the image than L" to the CPU 25. It is located at the home position (see Figure 1). Using this sensor, when the power is turned on, the first thing that happens is Ho! +: Move the scanner 10 and then move to the home position for a predetermined magnification.

The above contents will be explained with reference to the flowchart shown in FIG. In the figure, CW indicates a forward direction (the direction in which the scanner 10 scans), and CCW indicates a reverse direction (the direction in which the scanner 10 returns).

First, it is determined whether the sensor 100 is outputting an "H" signal (S202). When the sensor 100 is outputting "H" Ho, this means that the reading section of the scanner 10 is located closer to the leading edge of the image than Ho, so the scanner motor 11 is reversed (S202) and the scanner 10 is driven by one pulse. (S208). Then, it is determined whether the output of the sensor 100 has been inverted (S210). When the output of the sensor 100 is inverted in step 5210, this means that the position of the reading section of the scanner 10 has reached Ha, and therefore the scanner 10 can read.

At this time, 0 is substituted into a counter LCNT indicating the position of the scanner 10. Counter LCNT is scanner motor 1
When 1 moves in the scan direction by one pulse, 1 is added, and when 1 moves in the return direction by one pulse, 1 is subtracted. Next, the number of pulses P of the scanner 10 to the home position with respect to the initial magnification inputted in advance to the CPU 25 from the operation unit is read (S216). Since the home position of the scanner 10 for the initial magnification is always in the scanning direction, the scanner motor 11 drives the scanner in the scanning direction one pulse at a time (3218). At the same time, the value of the counter LCNT is incremented by 1 (S220). This operation is repeated until the counter LCNT matches the number of pulses P to the home position (S222).

If NO is determined in step 5202, scanner 1
Since the position of the reading section 0 is further away from the leading edge of the image than Ho, the motor rotation direction of the scanner motor 11 is set to the scanning direction (S206), and the scanner motor 11 is driven by one pulse (9208). If the output of the sensor 100 is not reversed in step 5210, the scanner motor 11
drives the scanner 10 by one pulse in accordance with each motor rotation direction (5208).

Next, details of abnormality detection in the scanner drive indicated by 5110 and 5112 in FIG. 5 will be explained.

Since a stepping motor is used as the scanner motor 10, once the home position is determined when the power is turned on, the CPU 25 can numerically control the scanner 10 thereafter. However, if an unexpected load change occurs, a tax adjustment phenomenon will occur. In that case, it is difficult for the CPU 25 to immediately detect scanner drive abnormality. Therefore, in this embodiment, the sensor 100 and the sensor 101 shown in FIG.
is used to detect anomalies associated with tax audits, etc. The abnormality detection items are as follows.

(1) When the sensor 100 and the sensor 101 become "L" while the scanner 10 is being driven, they stop generating pulses and apply a brake to the scanner motor 11. This will be displayed as a problem on the display of the copier.

(2) At the end of the scan, turn H at the timing of immersion.

The scanner 10 is driven until the counter LCN at that time is
If the value of T is larger than the allowable error, it is determined that a tax adjustment has occurred, and compensation processing is performed.

The flowchart for abnormality detection 1 will be described in detail with reference to FIG. As described above, the sensor 100 is not turned on except when the power is turned on. Furthermore, the sensor 101 is also installed so that it is not normally turned on.

Referring to FIG. 7, in the flow of abnormality detection 1, it is first determined whether sensor 100 or sensor 101 is turned on (S302). Next, it is determined whether a scan is being executed (5304).

As described above, both the sensor 100 and the sensor 101 are installed so that they are not normally turned on during scanning.

Therefore, if these sensors are turned on, it may be determined that there is an abnormality. Therefore, when the determination in step 5304 is YES, the motor drive pulse of the scanner motor 11 is stopped (S306). Next, a message indicating that there is a trouble is displayed on the operation unit of the copying machine (8308). Then, 1 is assigned to a trouble flag indicating that the copying machine is in trouble (3310).

N in steps 5302 and 5304, respectively.
If it is determined that the copying machine is not in trouble, the processing flow returns.

Next, abnormality detection 2 will be explained. If the tax adjustment phenomenon does not occur, the distance between the scan start home position and the sensor 100 at the given magnification should be constant. Therefore, the scanner 10 is actually moved at this timing, the number of movement steps from the scan start home position until the sensor 100 is turned on is counted, and the distance is measured.

In that case, scan Scanner 1 at a sufficiently slow speed to avoid tax adjustment.
0 is driven. It is determined whether the scanner 10 is in the tax adjustment state based on the difference between the distance of the n1 constant result and a predetermined target value. This process will be explained with reference to the flowchart of abnormality detection 2 shown in FIG. In the flow of abnormality detection 2, it is first determined whether the scanner 10 is in a stopped state (S402). If the scanner 10 is in a stopped state (YES in S402), it is determined whether there is an operation request for abnormality detection 2 (3404). If there is an operation request for abnormality detection 2 (YES in S404), the scanner 10 is driven at low speed to the position of the sensor 100 by the scanner motor 11, and the distance is measured using the number of pulses at that time (S4
06). Next, a predetermined target value and step 5406
The difference ε from the measured value obtained in (840g) is calculated. It is determined whether ε is less than or equal to a value sufficiently close to 0 (additional value 1) within the measurement error range (5410). If ε is less than or equal to α (YES in S410), it is determined that the scanner 10 is normal, and the scanner 10 is returned to the home position where scanning is started (S412). When it is determined in step 5410 that the difference ε is greater than 1, it is determined whether the difference ε is greater than or equal to a predetermined value 2 (S414). If it is determined in step 5414 that the difference ε is greater than or equal to the predetermined value of 2 (YES in S414), it is determined that an uncompensable tax adjustment has occurred, and as in abnormality detection 1, a trouble condition is detected in the operation unit of the copying machine. (S418). Then, a trouble flag for indicating the occurrence of a trouble is set to 1 (S420). When it is determined in step 5414 that the difference ε is smaller than the predetermined value fL2, it is determined that the tax adjustment is compensable, and subsequent operations are restricted, and a display indicating that restrictions have been added to the scanning unit of the copying machine is displayed. (S416), and the scanner 10 is returned to the position before measurement (5412).

Next, the above compensation operation will be explained. FIG. 9 is a diagram showing the relationship between the rotation speed and torque of a stepping motor generally used as the scanner motor 11. The X-axis shows the rotation speed, and the Y-axis shows the torque. Referring to FIG. 9, the output torque of the stepping motor decreases as the rotational speed increases. This means that t in FIG.
This means that the torque margin is the smallest in the acceleration state around the time indicated by and the deceleration state immediately after the time indicated by t6. Originally, the scanner motor 11 is selected so as to ensure a margin of torque in these respects, but it is conceivable that some tax adjustment may occur in these respects due to unexpected load fluctuations. This tax adjustment is done by reducing the acceleration and deceleration at the time of return (that is, from t4 to
t) or by increasing the time between scanner 1
This can be avoided by lowering the zero return speed itself. At this time, the disadvantage is that the return completion time is delayed, and the scanner operation that normally would complete the return during one rotation of the transfer drum cannot be performed.
As a result, the transfer drum must be left idling in the next copying process. Therefore, a warning is displayed on the operation unit to inform the user of this fact.

At a small magnification during reading scan, the scanner 10 is driven with a speed curve similar to the speed curve during return. In this case, if the acceleration is made smaller, the 0-tI time becomes longer and the acceleration of the scanner 10 cannot be completed within the time from the fall of the TBASE signal to the registration position, which causes a problem.

Furthermore, since the distance required for acceleration also increases, the copying machine must be made larger in advance. From the above points, it is necessary to restrict the use of copying machines at low magnifications. For example, originally 0. If the copying machine can be used within the magnification range of 5x to 4x, the use of the copying machine will be limited to the range of 0.7x to 4x when compensation is made under tax regulations.
The fact that this restriction has been added is displayed as a warning on the operation panel, similar to the example above.

The abnormality detection 2 measurement may be performed, for example, after a certain period of time after the end of the previous copying operation (for example, during auto-clear if the copying machine has an auto-clear mode). Alternatively, when the user looks at the image and feels that there may be a shift between colors in the sub-scanning direction, the user may request the abnormality detection 2 operation through the operation unit. Further, the above two operations may be used together.

Next, the test scan will be explained. A test scan is a scan that determines whether the step-out phenomenon has actually been suppressed when the scanner of a copying machine is out of synchronization, with restrictions on the copying magnification and scanner acceleration as described above. means. After the first copy switch-on after the restriction has been applied, a scanning operation at the first magnification within the restriction range is first performed before feeding the copy sheet. After the scanner 10 returns, the distance from the sensor 100 is n
1 is determined. If the measurement result at this time is determined to be tax-adjusted, then the process proceeds to the copying process. Further, after the restriction is applied, a briscan may be performed once in the operation mode each time the copy switch is turned on to determine whether there is a tax adjustment. If it is determined that there is a step-out in the scanner 10 in the above test scan, the subsequent copying operation will be stopped as a trouble.

The above contents will be explained with reference to test scan flowcharts in FIGS. 10 and 11. FIG. 10 is a flowchart showing the processing of test scan part 1. In the first test scan, it is first determined whether or not this is the first copy request after restriction (S502). Step 5502
When it is determined that this is the first copy request (YES),
First, paper feeding is not performed (S504). Next, the scanner 10 is blisscanned at the minimum magnification within the limited range (55
06). Then scan 10 to sensor 100 at low speed.
is moved, and the distance of scanner deviation is measured using the number of pulses at this time (5508). The deviation value ε is expressed as the difference between a predetermined target value and a measured value (S 510
). Next, it is determined whether the deviation ε is close to 0 within the 1111 constant error range, for example, a gun, or less (S 512).
. If the difference ε is less than 1 (YES in step 5512)
), the scanner 10 is returned to the position before measurement (S5
14), the paper feed wait suspended in step 5504 is canceled (S516). If the difference ε is greater than 1 in step 5512, a trouble flag is displayed on the operation unit of the copying machine (5518), and 1 is assigned to a trouble flag for trouble display (S520).

Note that if it is determined in step 5502 that this is not the first print request after the restriction, the processing flow is returned.

FIG. 11 is a flowchart showing the second test scan method during compensation operation.

Referring to FIG. 11, according to the second test scan method, it is first determined whether or not any restrictions are imposed on the scanner 10 (S602), and when it is determined that there are restrictions (S602) (YES), paper feed wait processing (S604) is performed to interrupt paper feeding, and blisscan is performed in the operation mode (S606). Then, the scanner 10 is moved to the sensor 100 at a low speed that does not cause tax adjustment, and the number of pulses at that time is Δ? J is determined, and the distance from the predetermined position is determined by 13 (9608). Next, the difference ε between the predetermined target value and the All constant value determined in step 5608 is calculated (S 610). Next, it is determined whether the difference ε is less than or equal to a predetermined value t1 close to 0 within the measurement error range (S612), and if the difference ε is less than or equal to the predetermined value (YES in step 5612), the scanner 10 is returned to the position before measurement (S614), and step 560
The paper feed wait process performed in step 4 is canceled (S 6
10).

If the difference e is larger than the predetermined value 1iilu in step 612 (NO), a trouble state is displayed on the operation panel of the copying machine (5618), and 1 is assigned to the trouble flag for displaying the trouble state. (S 620
).

[Effects of the Invention] As described above, according to the present invention, the image reading scanner is caused to scan according to the constraint conditions, and the second comparing means compares the return position of the scanner after scanning is completed under the constraint conditions with a predetermined value. The difference from the initial position is compared to determine whether the constraint conditions are such that they do not impede image reading. As a result, if the constraint condition does not interfere with image reading, image reading is performed with the constraint condition, and if the constraint condition does not interfere with image reading,
Image reading is not performed. Therefore, if the tax adjustment is minute, it is possible to provide an image reading device that can read an image under conditions in which the tax adjustment is unlikely to occur, and can confirm whether or not the conditions in which the tax adjustment is unlikely to occur are appropriate. There is an effect.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the overall configuration of a digital color copying machine, FIG. 2 is a block diagram showing the configuration of the read signal processing section 20, and FIG. 3A is a correction by shifting the home position of the scanner. FIG. 3B is a diagram showing the positional relationship between the leading edge of the image and the home position at each magnification, and FIG. 4 is a graph showing the relationship between time and speed in the movement of the scanner. FIG. 5 is a main flowchart for detecting the tax adjustment status of the scanner, FIG. 6 is a flowchart showing a subroutine for initializing the scanner, FIG. 7 is a flowchart showing a subroutine for abnormality detection position, and FIG. FIG. 8 is a flowchart showing the subroutine of abnormality detection 2, FIG. 9 is a graph showing the relationship between the rotation speed and torque of the stepping motor, and FIG. 10 is a flowchart showing the subroutine of test scan part 1. FIG. 11 is a flowchart showing the subroutine of test scan part 2. 10 is a scanner, 11 is a scanner motor, 16 is a document table, 20 is a signal processing section, and 100 and 101 are sensors. In addition, in the figure, is shown. The same symbols are the same, or corresponding parts (two other people) Channel 10 Fig. 38 Fig. 3B Fig. S Speed Fig. 4 Ditch '''f Fig. 10 Fig. 8 Fig. Q Rotation t (PPS) No. 10 Kuman 11 figure

Claims (1)

[Scope of Claims] An image reading scanner for reading an image of an original while scanning the original by reciprocating relative to the original using a stepping motor; The scanning starts from a first initial position of the first position, and returns to a second position after the scanning, the scanning is performed under a plurality of conditions, and the plurality of conditions are variable; first scanner position detection means for detecting a difference between the initial position and the second position;
and a predetermined second value larger than the first value; and the comparing means compares the difference between the first value and the second value.
scanning condition constraining means for constraining the scanning condition to some of the plurality of conditions when determining that the scanning condition is between the values of the plurality of conditions; Thereafter, the scanner returns to the third position, and includes a second scanner position detecting means for detecting a second difference between the first initial position and the third position, and a second scanner position detecting means for detecting a second difference between the first initial position and the third position, and a second scanner position detecting means for detecting a second difference between the first initial position and the third position; a second comparing means for comparing a first value and a second value; and stopping the scanning when the second comparing means determines that the second difference is greater than the first value. An image reading device including a scanning stop means.