JP2001111794A - Image reader and image processor provided with the image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To output image data without image deterioration by preventing a line offset caused by interruption of reading and avoiding an acceleration/ deceleration period of a running body moving a line sensor. SOLUTION: On the way of reading, a CPU 37 receiving a memory near full interrupt of a buffer memory from an SiBC 35 outputs a stop operation signal of the sensor running body and a signal DATA-CTL with an input of an LSYNC from an NIPU 33 just after the reception of the interrupt, and shuts an LGATE to interrupt image data output. The sensor is returned to a moving start position side by a prescribed distance from the position at the interrupt, then the CPU 37 restarts the movement of the sensor by receiving a memory idle interrupt, matches timing with a line period for the point of time when the sensor reaches the position at the interrupt by a prescribed moving speed, opens the LGATE synchronously with the line period and restarts transfer of the sensor output to the memory.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus in which a reading scanning section is moved, and more particularly, to an image reading apparatus which moves a reading scanning section in accordance with a use state (full / empty) of a buffer memory for holding read image data. An image reading apparatus for interrupting the output of the read image data, stopping the movement of the reading scanning unit, and restarting the input of the image data from the interrupted position, and an image processing apparatus including the image reading apparatus (for example, a copying machine, a facsimile , A scanner, a device combining the above functions, or a filing device for storing image data).

[0002]

2. Description of the Related Art Conventionally, in a digital copying machine, an image scanner, or the like, reading scanning is performed while a traveling body equipped with a line image sensor or a reading optical system is moved by driving a stepping motor. In this scanning, the reading may be interrupted and the traveling body may be stopped. In this case, the speed at the position where the reading was interrupted and the position where the reading was resumed, avoiding the acceleration / deceleration period, and the speed at that position are matched (the traveling It has been proposed that the deceleration period be returned once and the entire vehicle should be driven at a constant speed. However, in this proposal, since the line cycle is not taken into account, there is a possibility that one line of the joint is shifted. In addition, as a method of stopping the running, restarting the running from the stop position without performing the return operation (reading without avoiding the acceleration / deceleration period), and stopping the motor fluctuation as a Although a device that stops the output is also considered, in the case of high-speed reading, an acceleration section of the drive motor is required, which is not suitable for high-speed control. A device that resynchronizes the main scanning line cycle (horizontal synchronization signal) with the motor pulse (encoder counter) to prevent line deviation has been considered, but it eliminates minute line deviation during resynchronization. It has not been done yet.

[0003]

When a line shift occurs in the above-mentioned conventional example, it does not pose a problem when reading at a low speed because the shift is difficult to understand. However, when reading is performed at a high speed, it appears more prominently. So it cannot be ignored. Also, when reading without avoiding the acceleration / deceleration period of the stepping motor, it is not necessary to worry about the line shift, and the image can be read at a high speed to some extent. appear. SUMMARY OF THE INVENTION The present invention relates to a problem of the prior art relating to the above-described reading interruption operation when the buffer memory is full in an image reading apparatus that performs a reading scan by moving a traveling body equipped with a line image sensor or a reading optical system by driving a stepping motor. An object of the present invention is to provide an image reading apparatus capable of outputting image data that does not cause image deterioration by preventing line deviation that may occur due to reading interruption and avoiding the acceleration / deceleration period of the traveling body. Apparatus and an image processing apparatus provided with the image reading apparatus (for example, a copying machine, a facsimile, a scanner,
It is another object of the present invention to provide a device that combines the above functions or a filing device that stores image data.

[0004]

According to a first aspect of the present invention, there is provided a line sensor for main-scanning and outputting read image data at a predetermined cycle, a sensor moving means for moving the line sensor in a sub-scanning direction, and a method for outputting output image data. Buffer memory to hold,
In an image reading apparatus having a sensor output transfer unit that transfers an output from a line sensor to a buffer memory, and a control unit that controls the sensor movement unit and the sensor output transfer unit, the control unit may be configured such that the buffer memory is in the middle of reading. When full, the transfer operation of the line sensor output to the buffer memory is interrupted in synchronization with the line cycle, and the line sensor is moved to return to the movement start position by a predetermined distance from the position at the time of the transfer interruption. Then, when the buffer memory becomes vacant, the movement of the line sensor is restarted so that the line sensor reaches a predetermined moving speed when the line sensor reaches the position at the time of the transfer interruption, and the timing is controlled so as to be synchronized with the line cycle. Restarts the transfer of sensor output to the buffer memory in synchronization with the line cycle of Constituting an image reading apparatus which comprises causing.

According to a second aspect of the present invention, in the image reading apparatus according to the first aspect, the control means activates the movement of the line sensor, which is resumed when a buffer memory becomes empty, in synchronization with the line cycle. It is characterized by the following.

According to a third aspect of the present invention, in the image reading apparatus according to the first or second aspect, the control means varies the time from when the line sensor resumes movement to when the line sensor reaches the position at the time of transfer interruption. It is characterized in that the timing with the cycle can be adjusted.

According to a fourth aspect of the present invention, in the image reading apparatus according to any one of the first to third aspects, the control means controls the predetermined time until the line sensor resumes movement and reaches a position at the time of transfer interruption. The characteristic is that the control operation of the characteristic for setting the moving speed is performed.

According to a fifth aspect of the present invention, there is provided an image processing apparatus including the image reading apparatus according to any one of the first to fourth aspects.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described based on the following embodiments shown in the accompanying drawings. FIG. 1 is a diagram showing an outline of the overall configuration of an image reading apparatus according to the present invention. FIG. 2 is a block diagram showing an outline of an overall configuration of a circuit mounted on the image reading apparatus according to the present invention. With reference to FIG. 1 and FIG. 2, a general description of an image reading apparatus according to the present invention will be given. The apparatus of the embodiment shown in FIG. 1 employs a configuration in which a document can be read in both a flat bed mode for fixing a document to be read and a document moving mode for reading while transporting the document. In the original fixing mode, the original placed on the original platen glass 1 is illuminated by an illumination lamp 3 integrated with the first mirror 2, and the reflected light thereof is reflected by the first mirror 2, the second mirror 4, Then, scanning is performed by a third mirror 5 integrally formed with the second mirror 4. Therefore, the first mirror 2 and the illumination lamp 3 and the second mirror 4 and the third mirror 5 can be moved in the direction A by using the traveling body motor 7 as a drive source. Thereafter, the reflected light is converged by the lens 31 and is irradiated on the CCD 6 to be photoelectrically converted.

On the other hand, in the original moving mode, the originals stacked on the original tray 8 pass through a reading position B by a pickup roller 9, a pair of registration rollers 10, a conveying drum 11, and a conveying roller 12, and then a pair of conveying rollers 13 and a discharge roller. The paper is sent to the paper roller pair 14 and discharged onto the paper discharge tray 32.
When the document passes through the reading position B, the original is irradiated by a stationary illumination lamp 3 which is moved near the reading position B, and the reflected light thereof is reflected by a first mirror 2, a second mirror 4, and a second mirror. The light is transmitted by a third mirror 5 integrally formed with the fourth mirror 4. Thereafter, the reflected light is focused by the lens 31 and
The light is irradiated on the CCD 6 and photoelectrically converted. The pickup roller 9 and the pair of registration rollers 10 are driven by a sheet feeding motor (not shown),
2. The transport roller pair 13 and the discharge roller pair 14 are driven by a transport motor (not shown).

In the original movement mode, a contact image sensor 15 is provided at the reading position C. The contact image sensor 15 includes a light source lamp such as an LED, a lens, and a sensor element (none is shown). When the document passes through the reading position C, the opposite surface (back surface) read at the reading position B is illuminated by the LED in the contact image sensor 15 installed at the reading position C, and the reflected light is adhered. The light is converged by the lens on the image sensor 15, irradiates the sensor element on the contact image sensor 15, and is photoelectrically converted. A white roller 17 is provided at an opposite portion of the contact image sensor 15 across the document, and is used as a white reference member for shading correction at the time of reading by the contact image sensor 15. Further, an endor unit 18 and an endor platen 19 are provided between the transport roller pair 13 and the paper discharge roller pair 14. The endorser 18 is composed of a printing section composed of alphabetic letters and numerals marked with ink, and a pressure solenoid (not shown) for pressing the printing section in the direction of the endoscope platen. Endorse the manuscript
8 and is fixed in the pressing direction by an endor platen 19, and alphabet characters and numerals can be printed on the original surface by pressing the endor 18 printing portion.

FIG. 2 shows a circuit that controls the reading operation of the above-described image reading apparatus, processes the read image signal, and generates image data. Referring to the circuit shown in FIG.
The outline of the processing of the read image signal will be described. The CCD on the SBU (sensor board unit) 20
The reflected light of the document entering the document 6 is converted into an analog signal having a voltage value according to the light intensity in the CCD 6. The analog signal is divided into odd bits and even bits and output. The analog image signal is input to an A / D converter after an analog processing circuit (not shown) has a dark potential portion removed on the SBU 20, an odd bit and an even bit are synthesized, and the gain is adjusted to a predetermined amplitude. Signaled.

The digitized image signal is transmitted to a NIPU 33 on an SCU (scanner control unit) 21.
After performing shading correction, gamma correction, MTF correction, and the like, the image is binarized and output as a video signal together with a page synchronization signal, a line synchronization signal, and an image clock. The video signal output from NIPU 33 is output to option IPU 26 via connector 34. The video signal output to the option IPU 26 is
Predetermined image processing is performed in the option IPU 26,
It is input to the SCU 21 again. The video signal input to the SCU 21 again is input to a selector (not shown). The other input of the selector is a video signal output from NIPU 33, and is an optional IPU.
At 26, whether or not to perform image processing can be selected. The video signal output from the selector is input to the SiBC 35 that manages image data storage means (DRAM), and is stored in an image memory composed of a DRAM. The image data stored in the image memory is sent to the SCSI controller 36 and transferred to an external device such as a personal computer.

The analog image signal photoelectrically converted by the contact image sensor 15 is digitally converted on the RSBU 16. The digitized image signal is sent to the RCU 23 after being subjected to shading correction on the RSBU 16. The RCU 23 is composed of an image memory composed of DRAM and SiBC for controlling the image data memory.
After temporarily storing the image data in the image memory, the SCU2
Transfer to 1. The image data sent from the RCU 23 to the SCU 21 and the image data output from the SiBC 35 on the SCU 21 are switchable, and any one of the image data is selected and transferred to the SCSI controller 36. On the SCU 21, a CPU 37, a ROM 38,
A RAM 39 is mounted, and the CPU 37
The controller 36 controls the controller 36 to communicate with an external device such as a personal computer. The CPU 37 also controls the timing of the traveling body motor 7, which is a stepping motor, the sheet feeding motor, and the transport motor. The ADU 30 has a function of relaying power supply of electrical components used in an automatic document feeder (ADF) unit. An input port connected to the CPU 37 on the SCU 21 is connected to the main body operation panel 28 via the IOB 24. A start switch (not shown) and an abort switch (not shown) are mounted on the main body operation panel 28. When each switch is pressed, the CPU 37 sets the switch to O through the input port.
N is detected.

FIG. 3 is a block diagram of a main part of a circuit related to a reading (image data output) interruption operation according to the present invention. This figure shows a part of the circuit elements in FIG. 2 (the same elements as those shown in FIG. 2 are denoted by the same reference numerals) and the flow of control signals and image data between the elements for explanation of the operation. The image data output interruption operation will be described with reference to the circuit shown in FIG.
U) 33 to LS to CCD drive unit SBU20
By outputting YNC (main scanning line synchronization signal) and LGATE (main scanning line data output period), the SBU 20 outputs image data. The flow of image data is SBU
20 → NIPU33 → Memory control LSI (Si
BC) 35 → SCSI controller 36 → external (PC etc.). This operation is not different from the conventional technology.

As a configuration unique to the present invention, the timing is detected by inputting a main scanning line synchronization (LSYNC) signal to the CPU 37, and data output control (ON / OFF of image data output from the CPU 37) is performed. DATA_CT
L) A signal is provided to the NIPU 33 for outputting a signal (some of which are provided as a known technique inside an image processing LSI, not shown, and which are controlled by rewriting internal registers). Also,
An interrupt (MEM_NEAR_FULL) signal generated when the memory state is full, near full, or empty from the SiBC 35 is input to the CPU 37. The state of the interrupt signal is determined by a register (not shown) provided inside the SiBC 35, and the state signal generating means itself is known. Further, the CPU 37 includes means described in detail below for generating and outputting a motor control signal for controlling the motor 40 for moving the traveling body as a series of image data output suspending operations.

Next, details of a series of image data output interruption operations performed by the circuit of FIG. 3 will be described with reference to the following embodiments. FIG. 4 is a time chart of a control signal for explaining the timing of the image data output interruption operation.
Shows a flowchart of the operation of the circuit shown in FIG. 3 at this time. In this embodiment, the LSYNC cycle is 0.25 msec, and the through-up distance is 15 mm (9 steps).
And The operation of this embodiment will be described with reference to FIGS. 4 and 5. First, the operation starts by moving a traveling body (a carriage for moving the scanning optical system in the sub-scanning direction in the original fixing mode). (S11) Then, when the next document reading position is reached, reading is started (S12). In the middle of reading, an interrupt (MEM_NEAR_FULL) signal is generated from the SiBC 35 when the memory becomes full just before the memory becomes full, and the CPU 37 detects this (S13).

Upon detecting the interrupt (MEM_NEAR_FULL) signal, the CPU 37 waits for the LSYNC input immediately after that, and sets the NI
When LSYNC is input from the PU 33 (S14), an operation of stopping (through-down) the running body is caused (S1).
5). At the same time, DATA_CTL = ON as the data output control signal
The signal is sent to the NIPU 33 to prohibit the output of the LGATE signal, thereby prohibiting the output of the image data to the memory near full SiBC 35 (S16).
This makes it possible to match the stop of the image data output with the beginning of the LSYNC cycle. When the traveling body is stopped (through-down) as described above, the through-down data prepared for driving the stepping motor may be arbitrarily determined, but the through-up distance is 15 mm (the number of steps is 9). According to the data, for example, Table 1 below
Can be used. According to the through-down data, as shown in the speed diagram of FIG. 4, the stop operation is started, and then the vehicle stops with a linear change in speed.
Takes c time.

[0019]

[Table 1]

Next, the operation from the stop of the image data output to the restart of the output of the image data will be described in detail with reference to the following embodiments. FIG. 6 is a time chart of a control signal for explaining the timing of the image data output suspending operation, and FIGS. 7 and 8 are flowcharts of the operation of the circuit shown in FIG. 3 at this time. In this embodiment, an image data output restart operation is performed as a series of operations following the image data output stop operation shown in the above embodiment (FIGS. 4 and 5). Therefore, the LSYNC cycle is 0.25 mse, as in the case of the image data output stop operation.
c, An example is shown in which the through-up distance is 15 mm (the number of steps is 9). The operation of this embodiment will be described with reference to FIGS. 6, 7 and 8. Since the traveling body is at the stop position due to the through-down operation at the time of the image data output stop operation shown in FIG. First, return control is performed in which the stepping motor is rotated in the reverse direction to move the traveling body at a position where restarting is performed (S21).

The return control of the traveling body is performed according to the flow shown in FIG. Here, the running body is started in the reverse direction using the data of Table 1 used for the previous stop operation for the through-up (S211), and the through-up is performed. When the through-up is completed (S212), the traveling body is at the position where the image data output in the previous operation is stopped at that time, and at the same time as the through-up is completed, the traveling body is slewed down using the same through-up data (S213). ). By this operation, the traveling body returns 30 mm from the stop position. In the above example, through-up / down was performed using the data in Table 1, but this condition setting (through-up distance of 15 mm
In (number of steps 9), it is necessary to correctly return the traveling body by 30 mm from the stop position, and the traveling body may be slowly returned by 30 mm at the self-starting speed as shown in FIG.

Next, the returning operation of the running body is performed, the running body in the stopped state is run again in the reading direction, and the output of the image data is resumed from the position where the output of the image data was previously stopped. Will be described. This operation is shown in FIG.
Of the flow from step S22 onward. After the return control of the traveling body is performed in step S21, a plurality of motor tables (through-up data) to be used when performing the through-up operation again are prepared, and an appropriate table is selected from the prepared plurality of tables (S22). ). For example, as the through-up data, data shown in the following Tables 2 to 4 in addition to the above Table 1 are prepared and can be selected from the data. Tables 1 to 4 all show the operation characteristics in which the distance is 15 mm (the number of steps is 9), but the time in each step is different, so that the speed changes differently and the time required for the through-up is different. .

[0023]

[Table 2]

[0024]

[Table 3]

[0025]

[Table 4]

After the motor table is selected in step S22, when the state of the memory under the control of the SiBC 35 becomes empty, a memory empty interrupt (MEM_EMPTY) signal is issued from the SiBC 35 as shown in FIG. 6C. And
The CPU 37 detects this (S23). Upon detecting the memory empty interrupt (MEM_EMPTY) signal, the CPU 37 waits for the LSYNC input immediately after that, and when LSYNC is input from the NIPU 33 (S24), drives the running body in a stopped state and starts the through-up operation. (S25). Thereafter, the end of the through-up operation or the end of the nine steps is checked (S26), and at the same time the end is checked, the DATA_CTL = OFF signal is set to N as the data output control signal.
Send to IPU33. Upon receiving this signal, NIPU 33
As shown in FIG. 6 (C), the LGATE signal output is restarted,
Image data output is SiBC35 with empty memory status
(S27). This makes it possible to output image data without positional deviation by adjusting the timing of restarting image data output to the LSYNC cycle that was previously prohibited.

Here, the operation based on the data exemplified in Tables 1 to 4 prepared as the through-up data selected in step S22 will be described. In the illustrated data, the position at the end of the through-up is the same, and only the time is different. As described above, by appropriately preparing a table having different times, the restart of the traveling body is performed after further waiting for the LSYNC input after the occurrence of the memory empty interrupt, and the adjustment with the LSYNC at the end of the through-up is performed. In addition, adjustment is facilitated. When the through-up data in Table 2 is selected, the through-up operation period is LS
Since it is an integral multiple of the YNC cycle (that is, 35.25 msec of the through-up operation period in Table 2 is a multiple of 0.25 msec of the LSYNC cycle), it is synchronized with LSYNC both at the start and end of the through-up. When the reading is resumed, that is, when the image data output is resumed (LGATE output is resumed), the line deviation of the output image can be eliminated.

When the through-up data in Table 3 is selected,
As compared with the through-up data in Tables 1 and 2 (the velocity diagram of FIG. 6C shows the characteristics according to Tables 1 and 2), the through-up operation period is longer, and the speed diagram in FIG. It has the characteristic shown by the solid line shown, and it is possible to stabilize the vibration of the motor and the like, and to stabilize the image. When the through-up data of Table 4 is selected, the through-up operation period becomes shorter than that of the through-up data of Tables 1 to 3, and has a characteristic shown by a broken line shown in the velocity diagram of FIG. By making the speed reach the constant speed earlier, it is possible to shorten the through-up time and shorten the total reading time.

[0029]

(1) Effects corresponding to the first and second aspects of the invention The buffer memory becomes full (near full) during reading, and the position where the image output from the line sensor is stopped, the line cycle, and the image output are determined. By matching the position of the restart and the timing of the line cycle, it is possible to prevent the displacement of one line at the seam and to read the image while avoiding the acceleration / deceleration period of the stepping motor. An image reading device that outputs image data can be provided. (2) Effects corresponding to the third aspect of the invention In addition to the effects of the above (1), the timing with the line cycle can be arbitrarily finely adjusted so that the position at which the image output is restarted can be selected. Therefore, it is possible to provide an image reading apparatus with less image deterioration. (3) Effects corresponding to the invention of claim 4 In addition to the effects of the above (1) and (2), a characteristic that the line sensor resumes movement and sets the predetermined movement speed before reaching the position at the time of transfer interruption. By performing the control operation described above and providing a constant speed period in the timing adjustment period with the line cycle, the timing of the reference position alignment can be arbitrarily adjusted when re-reading, so that the reading speed is increased. A possible image reading device can be provided. (4) Effects corresponding to the invention of claim 5 The effects of the above (1) to (3) can be obtained by using an image processing apparatus such as a copying machine, a facsimile, a scanner, a device combining the above functions, or a filing device for storing image data. To improve the performance of the image processing apparatus.

[Brief description of the drawings]

FIG. 1 shows an outline of the overall configuration of an image reading apparatus according to the present invention.

FIG. 2 shows an outline of an overall configuration of a circuit mounted on the image reading apparatus according to the present invention.

FIG. 3 is a block diagram of a main part of a circuit related to an image data output interruption operation according to the present invention.

FIG. 4 is a time chart of a control signal for explaining a timing of an image data output suspending operation.

5 shows a flowchart of the circuit shown in FIG. 3 for performing the image data output interrupting operation of FIG. 4;

FIG. 6 is a time chart of a control signal for explaining the timing of an image data output interruption operation.

7 shows a flowchart of the circuit shown in FIG. 3 for performing the image data output interruption operation of FIG. 6;

8 shows details of the traveling body return control in the flowchart of FIG.

FIG. 9 shows a speed diagram of a through-up operation when the data of Tables 3 and 4 are used.

[Explanation of symbols]

1 ... platen glass 3 ... lighting lamp
6 ... CCD, 8 ... Document tray,
15: Contact image sensor (CIS), 16: RSBU
(Reverse sensor board unit), 90 ... 20 ...
SBU (Sensor Board Unit), 21 ... SCU (Scanner Control Unit), 33 ... NIPU,
35 ... SiBC, 36 ... SCSI controller, 37 ... CPU, 40 ... Traveling motor.

Claims (5)

[Claims] 1. A line sensor for main-scanning and outputting read image data at a predetermined cycle, a sensor moving means for moving the line sensor in a sub-scanning direction, a buffer memory for holding output image data, and an output from the line sensor. In an image reading apparatus having a sensor output transfer unit that transfers the data to a buffer memory and a control unit that controls the sensor movement unit and the sensor output transfer unit, the control unit includes:
When the buffer memory becomes full during reading,
The transfer operation of the line sensor output to the buffer memory is interrupted in synchronization with the line cycle, and the line sensor is moved to return to the movement start position by a predetermined distance from the position at the time of the transfer interruption. Occurs, the movement of the line sensor is restarted, the line sensor reaches a predetermined moving speed when the line sensor reaches the position at the time of the transfer interruption, and is controlled so as to be synchronized with the line cycle, and synchronized with the line cycle at that time. An image reading device for resuming a transfer operation of a sensor output to a buffer memory. 2. The image reading apparatus according to claim 1, wherein the control means starts the movement of the line sensor, which is restarted when the buffer memory becomes empty, in synchronization with the line cycle. Image reading device. 3. The image reading apparatus according to claim 1, wherein the control unit changes the time from when the line sensor resumes the movement to when the line sensor reaches the position at the time of the transfer interruption to determine the timing with the line cycle. An image reading device characterized in that it is adjustable. 4. The image reading apparatus according to claim 1, wherein the control unit sets the predetermined moving speed until the line sensor restarts moving and reaches a position at the time of transfer interruption. An image reading apparatus, wherein a characteristic control operation is performed. 5. An image processing apparatus comprising the image reading apparatus according to claim 1.