JP6147978B2 - Image reading apparatus and control method thereof - Google Patents

Description

  The present invention relates to an image reading apparatus (scanner unit) that reads an original image, such as an image scanner or a facsimile machine, and a control method thereof. In particular, it is suitable for use in an image reading apparatus configured to irradiate a document with a linear light source using LEDs and to capture a linear image with a contact image sensor (CIS).

  2. Description of the Related Art Conventionally, in an image reading apparatus, there are cases where image data cannot be transferred for some reason, such as when the free space in the buffer memory becomes small during image reading or when the host PC becomes busy. In such a case, the movement of the original and the image reading operation are temporarily interrupted, and a transition is made to an intermittent reading mode in which the state waits until these states are recovered.

  If the mode is shifted to the intermittent reading mode during image reading, the image data of the portion where the movement of the document is stopped is unnecessary, so that the image data read during the intermittent reading mode is not output to an external device such as the host PC. In the image reading apparatus, processing such as discarding is performed. Further, since the image data read during the stop is data that is discarded, there is no need to receive the reflected light of the document and there is no problem even if the light source is not turned on. Therefore, an image reading apparatus configured to turn off the light source during the intermittent reading mode and not wastefully use electricity has been proposed (for example, Patent Document 1).

Japanese Patent Laid-Open No. 10-23219

  However, in order to stabilize the operation at the time of returning from the intermittent reading mode, the conventional technique operates in the same manner as in the normal reading operation even though the document is not moved during the intermittent reading mode. It was. That is, control signals are supplied to the image sensor, the operational amplifier, the A / D converter, or the AFE (Analog Front End IC) in the same manner as in a normal reading operation, and they are operated. For this reason, even during the intermittent reading mode, the LED is turned off, and power that is the same as that during normal reading is consumed.

The present invention has been made to solve the above-described problems, and an image reading apparatus according to the present invention has the following configuration. That is,
An image reading device that irradiates a document with light from a light source, photoelectrically converts reflected light from the document, and reads an image of the document,
Having an intermittent reading mode for temporarily interrupting a reading operation of reading the image of the original;
Monitoring means for monitoring the analog signal converted by the photoelectric conversion;
When shifting to the intermittent reading mode under specific conditions during the reading operation, the signal to the drive system for moving the document, the signal to the reading system for reading an image by the photoelectric conversion, and the light source Stop means for stopping the supply of the signal to be lit,
When returning from the intermittent reading mode, the supply of signals to the drive system in a stopped state by the stop means, a signal to the reading system subjected sheet, said analog signal is equal to or less than a predetermined value Is detected by the monitoring means, resuming means for supplying a signal for turning on the light source and a signal to the drive system to resume the reading operation;
It is characterized by having.

  According to the present invention, it is possible to suppress unnecessary power consumption when shifting to the intermittent reading mode under a specific condition during a reading operation.

FIG. 3 is a cross-sectional view illustrating an outline of the image reading apparatus. The figure which shows the detailed structure of a line sensor unit. The figure which shows the connection relationship of the drive gear in a separation feeding part. 1 is a block diagram illustrating an outline of a configuration of an image reading apparatus according to a first embodiment. 6 is a flowchart illustrating the operation of the image reading apparatus according to the first embodiment. FIG. 6 is a block diagram illustrating an outline of a configuration of an image reading apparatus according to a second embodiment. 9 is a flowchart showing the operation of the image reading apparatus in the second embodiment. The block diagram which shows the outline of a structure of the image reading apparatus in 3rd embodiment. 10 is a flowchart illustrating the operation of the image reading apparatus according to the third embodiment. FIG. 10 is a block diagram illustrating an outline of a configuration of an image reading apparatus according to a fourth embodiment. 10 is a flowchart illustrating an operation of an image reading apparatus according to a fourth embodiment. FIG. 10 is a block diagram illustrating an outline of a configuration of an image reading apparatus according to a fifth embodiment. 10 is a flowchart illustrating an operation of an image reading apparatus according to a fifth embodiment. FIG. 10 is a block diagram illustrating an outline of a configuration of an image reading apparatus according to a sixth embodiment. 10 is a flowchart showing the operation of the image reading apparatus in the sixth embodiment.

  Hereinafter, embodiments for carrying out the invention will be described in detail with reference to the drawings. First, an outline of an image reading apparatus as an application example of the present invention will be described below with reference to a cross-sectional view shown in FIG.

  As illustrated in FIG. 1, the image reading apparatus 100 includes, in an image reading apparatus main body 100A, a sheet stacking unit 100B that is a sheet storing unit that stacks and stores sheets S, and a line sensor unit 103 that reads an image on the sheet S. In the present embodiment, the line sensor unit 103 uses a contact image sensor (CIS).

  Here, the detailed structure of the line sensor unit 103 will be described with reference to FIG. As shown in FIG. 2, the line sensor unit 103 includes a light guide 201 for diffusing the light from the LED 204 as a light source in a line and a light guide 202 for diffusing the light from the LED 205. ing. A rod lens array 203 is provided between the light guides 201 and 202 to guide the light reflected from the document to the CIS. Although not shown in the figure, a CIS substrate is installed in the back of the rod lens array 203. The LEDs 204 and 205 are red (R), green (G), and blue (B) LEDs, respectively, and are connected to a drive circuit (not shown).

  Returning to FIG. 1, a sheet feeding device 100 </ b> C that feeds the sheet S stored in the sheet stacking unit 100 </ b> B to the line sensor unit 103 is disposed in the image reading apparatus main body 100 </ b> A. The sheet feeding device 100C includes a feeding roller 1 that is a feeding rotating body and a separation roller 2 that is a separating rotating body that is in pressure contact with the feeding roller 1, and separates the sheets S stacked on the sheet stacking unit 100B one by one. A separating and feeding unit. Note that a drive unit for driving the feed roller 1 and the separation roller 2 is a feed motor 3. The rotation of the feed motor 3 is transmitted to the transport rollers 102a and 105, the platen roller 103a, and the paper discharge rollers 104 and 104b by a drive gear (not shown).

  Next, the connection relationship of the drive gears in the above-described separation feeding unit will be described with reference to FIG. As shown in FIG. 3, a drive gear 25 for driving the feed roller 1 is connected to a gear group 34 for transmitting the drive of the feed motor 3 via a one-way clutch 28, and is connected to the feed roller shaft 5a. Further, the rotational force of the drive gear 25 is transmitted to the shaft 6 a by the drive gear 27 fixed to the gear 26 and the shaft 6 a of the separation roller 2. As a result, the separation roller 2 rotates via the torque limiter 31 mounted inside the separation roller 2.

  Here, the feed roller 1 rotates in the sheet conveying direction, and the separation roller 2 is formed of an elastic body, and power is transmitted so as to rotate in the direction opposite to the sheet conveying direction. In addition, a torque limiter is provided in the drive transmission path of the separation roller 2, and follows the sheet conveyance direction when there is no sheet S or when one sheet is conveyed between the feed roller 1 and the separation roller 2. Rotate (turn around). However, in a state where a plurality of overlapping sheets S have entered between these rollers, it is possible to separate and convey the sheets S one by one by configuring the separation roller 2 to rotate in the direction opposite to the sheet conveying direction. Yes.

[First embodiment]
Next, an outline of the configuration of the image reading apparatus according to the first embodiment will be described with reference to the block diagram shown in FIG. A contact image sensor (CIS) 401 is composed of photoelectric conversion elements arranged in a line, converts the light reflected from the original by the light sources 204 and 205 shown in FIG. Output. Specifically, when a line head signal is input from the reading operation control unit 404, the CIS 401 picks up and accumulates the reflected light that the light sources 204 and 205 irradiate a document (not shown). Thereafter, photoelectric conversion is performed, and an analog signal is output to the amplification circuit 402 at the next stage in accordance with the drive clock. The amplifier circuit 402 amplifies the analog signal output from the CIS 401. The amplifier circuit 402 can adjust the gain according to an instruction from the outside and amplify the analog signal to a desired value.

  The analog signal amplified by the amplifier circuit 402 is converted into a digital signal having an arbitrary bit width by the A / D conversion unit 403 and output to the reading operation control unit 404 in accordance with the drive clock. Specifically, the A / D conversion unit 403 samples an analog signal in accordance with the sample timing signal from the reading operation control unit 404. Note that the amplifier circuit 402 and the A / D converter 403 may be a single IC using an AFE (Analog Front End IC).

  The reading operation control unit 404 supplies a driving signal to the reading system, supplies a signal for controlling the timing of turning on the light source, supplies a control signal to the driving system, and the like, and also outputs an analog signal that has been A / D converted. Has the function of monitoring the value. Here, the reading system is the CIS 401, the amplifier circuit 402, and the A / D conversion unit 403, or the CIS 401 and the AFE.

  The light source lighting unit 405 includes a constant current circuit or the like, and lights the light sources 204 and 205 in accordance with the light source lighting signal from the reading operation control unit 404. The light sources 204 and 205 are composed of red, green, and blue LEDs as described above, and are configured such that the reading operation control unit 404 and the light source lighting unit 405 can individually light each LED.

  The drive control unit 406 controls rotation, stop, speed, and the like of the feed motor 3 in accordance with a drive control signal (various instructions) from the reading operation control unit 404. The buffer memory 407 temporarily stores the image data input to the reading operation control unit 404 after being digitally converted by the A / D conversion unit 403. The external I / F unit 408 performs control when the reading operation control unit 404 transmits the image data stored in the buffer memory 407 to a host PC (not shown) connected to the image reading apparatus 100.

  The operation of the image reading apparatus 100 having the above configuration will be described with reference to the flowchart shown in FIG. In the first embodiment, after the reading process is started, when there is not enough free space to capture the image data in the buffer memory 407, the operation shifts to the intermittent reading mode in which the movement of the document and the image reading operation are temporarily interrupted. A process for reducing power consumption will be described.

  Note that the transition to the intermittent reading mode is not limited to when the buffer memory 407 has run out of space, but also when certain conditions are met, such as when the host PC cannot receive image data due to other processing. Is done by.

  First, in S501, when a scan start is instructed from the connected host PC or the like, the reading operation control unit 404 outputs a drive signal to each unit and circuit. Specifically, the drive clock and the line head signal are output to the CIS 401, the drive signal is output to the amplifier circuit 402, and the sample timing signal and the drive clock are output to the A / D converter 403. On the other hand, the CIS 401 accumulates charges according to the line head signal from the reading operation control unit 404 and outputs the accumulated charges according to the drive clock. By repeating the reading operation on the photoelectric conversion element a predetermined number of times, the charge accumulated in the CIS 401 is discharged (reset) when the operation is stopped, and the normal operation state is restored.

  In step S <b> 502, the reading operation control unit 404 determines whether the CIS 401 is in a normal operation state based on an analog signal output from the CIS 401. Normally, the CIS 401 is in a state where the amount of accumulated charge is saturated due to the influence of external light or the like while the reading operation is stopped. In this case, when the CIS 401 is driven in a state where the light sources 204 and 205 are not turned on, the accumulated charges are removed, and an analog signal finally output from the CIS 401 becomes an output value in a dark state. This change in the output value (whether it has reached a predetermined value) is determined by the reading operation control unit 404 monitoring the digital data output from the A / D conversion unit 403.

  In step S503, after the recovery operation is completed, the reading operation control unit 404 outputs a light source lighting signal to the light source lighting unit 405. In step S504, the reading operation control unit 404 outputs a drive control signal instructing driving to the drive control unit 406. In response to this instruction, the drive control unit 406 drives the feed motor 3 to convey (move) the document. It should be noted that the light source lighting signal may be configured to be supplied after the document described later reaches the reading start position instead of S503.

  In step S <b> 505, the reading operation control unit 404 determines whether the document has reached the reading start position. If the document has reached the reading operation control unit 404, the process proceeds to step S <b> 506 and there is a free space in the buffer memory 407 to capture image data. Check whether or not. Here, when the buffer memory 407 has sufficient free space, the reading operation control unit 404 advances the processing to S507 and takes the image data line by line into the buffer memory 407.

  In step S <b> 508, the reading operation control unit 404 starts a transfer process to the host PC in parallel with the image data capturing process. Specifically, when image data is stored in the buffer memory 407 for the amount transferred to the host PC, the stored image data is transferred to the host PC via the external I / F unit 408. This transfer process is assumed to be performed asynchronously with the image data capturing process.

  Next, in step S509, the reading operation control unit 404 determines whether or not one page of the document has been completed. If it has been completed, the process proceeds to step S510, and a drive control signal that instructs the stop of the feed motor 3 is driven. The data is output to the unit 406. In step S511, the reading operation control unit 404 stops outputting drive signals to the respective units and circuits.

  On the other hand, if it is determined in S506 that the buffer memory 407 has no free space, the reading operation control unit 404 advances the process to S512. In S512, since the reading operation control unit 404 cannot capture image data, a driving control signal instructing the stop of the feed motor 3 is output to the driving control unit 406, and the reading operation is temporarily interrupted. In step S513, the reading operation control unit 404 stops all the drive signals supplied to the CIS 401, the amplifier circuit 402, the A / D conversion unit 403, and the light source lighting unit 405.

  By controlling in this way, the CIS 401, the amplifier circuit 402, the A / D conversion unit 403, and the light source lighting unit 405 do not operate while the reading operation is stopped, so that useless power consumption can be suppressed.

  Furthermore, when the free space of the buffer memory 407 remains for one line or more in S506 described above, it is possible to capture the image data immediately before the reading operation is interrupted by determining that there is free space. In addition, before the reading operation control unit 404 temporarily stops the reading operation, the line head signal is input to the CIS 401 after one scanning time or more has elapsed from the previous line head signal. As a result, the charge accumulated up to that time can be taken out from the CIS 401, and abnormal data can be output or data can be prevented from being lost.

  Next, in S514, the process waits until the buffer memory 407 has enough space by the transfer processing to the host PC. When the space is available, the process proceeds to S515, and the reading operation control unit 404 returns from the intermittent reading mode to perform the reading operation. To resume. Specifically, the same processes as S501 to S504 described above are performed from S515 to S518. As a result, while the reading operation is stopped, the charge accumulated in the CIS 401 is removed, and the reading operation control unit 404 can determine that this charge has been released, and the CIS 401 can be operated from a normal state.

  According to the first embodiment, the operation is shifted to the intermittent reading mode, the scanning operation is stopped, the control signal to each device is stopped, and the operation of each device is stopped, thereby reducing the power consumption during the waiting time. It becomes possible to make it.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described in detail with reference to the drawings. In the second embodiment, a power supply control unit is further added to the configuration of the image reading apparatus in the first embodiment shown in FIG. 4, and the power supplied to each unit and circuit is controlled when shifting to the intermittent reading mode. To do.

  An outline of the configuration of the image reading apparatus according to the second embodiment will be described with reference to a block diagram shown in FIG. In addition, the same code | symbol is attached | subjected to each part and circuit which have the function similar to 1st embodiment shown in FIG. 4, and description is abbreviate | omitted.

  As shown in FIG. 6, in the second embodiment, when the power control unit 601 is connected to the reading operation control unit 404 and the reading operation control unit 404 determines that there is no free space in the buffer memory 407, the power control unit 601. To reduce power consumption. That is, the power supply control unit 601 turns on / off the power supplied to the CIS 401, the amplifier circuit 402, the A / D conversion unit 403, and the light source lighting unit 405 according to an instruction from the reading operation control unit 404.

  Here, the operation of the image reading apparatus in the second embodiment will be described with reference to the flowchart shown in FIG. Note that the processing in S701 to S713 and S717 to S720 shown in FIG. 7 is the same as the processing in S501 to S513 and S515 to S518 shown in FIG. 5 described in the first embodiment, and the description thereof will be omitted.

  In S706, when the reading operation control unit 404 determines that there is no free space in the buffer memory 407, the reading operation control unit 404 shifts to the intermittent reading mode, instructs the stop of the feed motor 3 (S712), and drives as in the first embodiment. All signals are stopped (S713).

  In step S <b> 714, the reading operation control unit 404 instructs the power supply control unit 601 to turn off the power supplied to the CIS 401, the amplifier circuit 402, the A / D conversion unit 403, and the light source lighting unit 405. In response to this instruction, the power control unit 601 turns off the power supply to each instructed unit and circuit. Accordingly, the power to the CIS 401, the amplifier circuit 402, the A / D conversion unit 403, and the light source lighting unit 405 is turned off while the reading operation is stopped, so that useless power can be reduced.

  In the second embodiment, for example, even when the host PC cannot receive image data by other processing for a long time, the power is turned off. The effect of reducing is obtained.

  Next, in step S715, the process waits until the buffer memory 407 has enough space by the transfer processing to the host PC. If there is space, the process proceeds to step S716, and the reading operation control unit 404 supplies power to the power control unit 601. Instruct to turn on. In response to this instruction, the power control unit 601 resumes power supply to the CIS 401, the amplifier circuit 402, the A / D conversion unit 403, and the light source lighting unit 405. The subsequent processing (S717 and subsequent steps) is the same as that in the first embodiment, and a description thereof will be omitted.

  According to the second embodiment, it is possible to reduce unnecessary power during the reading operation by shifting to the intermittent reading mode and turning off the power to each unit and circuit. Even if it takes a long time to transfer the image data while the reading operation is stopped, the power is turned off during that time, so that the effect of further reducing the power can be obtained.

[Third embodiment]
Next, a third embodiment according to the present invention will be described in detail with reference to the drawings. In the first embodiment, the state of the CIS 401 is detected by the output of the A / D conversion unit 403. In the third embodiment, the configuration of the image reading apparatus in the first embodiment shown in FIG. An analog signal monitoring unit is provided for direct detection. As a result, the state of the CIS 401 can be detected without driving the amplifier circuit 402 and the A / D converter 403, and the power consumption can be further reduced as compared with the first embodiment.

  An outline of the configuration of the image reading apparatus according to the third embodiment will be described with reference to a block diagram shown in FIG. In addition, the same code | symbol is attached | subjected to each part and circuit which have the function similar to 1st embodiment shown in FIG. 4, and description is abbreviate | omitted.

  As shown in FIG. 8, the third embodiment further includes an analog signal monitoring unit 801 that monitors an analog signal output by the CIS 401, and is configured so that the reading operation control unit 404 can directly detect the state of the CIS 401. Yes. Here, the analog signal monitoring unit 801 monitors the analog signal output from the CIS 401 and, when detecting that the level of the analog signal falls within a predetermined value, notifies the reading operation control unit 404 of the state. Note that the analog signal monitoring unit 801 may be configured with, for example, a comparator.

  The analog signal monitoring unit 801 monitors the analog signal output from the CIS 401, but may be configured to monitor the analog signal amplified by the amplifier circuit 402.

  Here, the operation of the image reading apparatus according to the third embodiment will be described with reference to the flowchart shown in FIG. First, in S <b> 901, when a scan start is instructed from the connected host PC or the like, the reading operation control unit 404 outputs a drive signal only to the CIS 401. In step S <b> 902, the reading operation control unit 404 determines whether the CIS 401 is in a normal operation state according to the analog signal output from the analog signal monitoring unit 801. When the reading operation control unit 404 determines that the output analog signal has reached a predetermined value, the reading operation control unit 404 advances the processing to S903 and outputs a drive signal to each unit and circuit other than the CIS 401.

  Note that the processing after S904 is the same as the processing after S504 shown in FIG. 1 described in the first embodiment, except that the processing at S915 and S917 is the same as the processing at S901 and S903.

  According to the third embodiment, the state of the CIS 401 can be detected without driving the amplifier circuit 402 and the A / D converter 403, and the power consumption can be further reduced as compared with the first embodiment.

[Fourth embodiment]
Next, a fourth embodiment according to the present invention will be described in detail with reference to the drawings. In the fourth embodiment, as shown in FIG. 10, the power control unit 601 of the second embodiment is added to the configuration of the image reading apparatus in the first embodiment shown in FIG. The analog signal monitoring unit 801 is provided.

  Here, the operation of the image reading apparatus according to the fourth embodiment will be described with reference to the flowchart shown in FIG. First, in S1101, when the start of scanning is instructed from the connected host PC or the like, the reading operation control unit 404 outputs a drive signal only to the CIS 401 as in the third embodiment. Next, in S1102 to S1113, the same processing as S902 to S913 shown in FIG. 9 described in the third embodiment is performed.

  Next, in S1114, the reading operation control unit 404 performs the same processing as S714 shown in FIG. 7 described in the second embodiment, that is, turns off the power supplied to each unit and circuit to the power supply control unit 601. Instruct. In response to this instruction, the power control unit 601 turns off the power supply to the CIS 401, the amplifier circuit 402, the A / D conversion unit 403, and the light source lighting unit 405.

  Next, in S1115, as in the second embodiment, the process waits until there is sufficient space in the buffer memory 407 by the transfer processing to the host PC, and the process proceeds to S1116 when there is space. This S1116 outputs the drive signal only to the same processing as S915 shown in FIG. 9 described in the third embodiment, that is, to the CIS 401 only. The subsequent processing (S1117 and subsequent steps) is the same as that of the third embodiment, and a description thereof will be omitted.

  According to the fourth embodiment, in addition to the effects in the first embodiment, the effects in the second and third embodiments can be obtained.

[Fifth embodiment]
Next, a fifth embodiment according to the present invention will be described in detail with reference to the drawings. In the fifth embodiment, a storage element for storing electric power supplied from an external power source is added to the configuration of the image reading apparatus in the first embodiment shown in FIG.

  An outline of the configuration of the image reading apparatus according to the fifth embodiment will be described with reference to a block diagram shown in FIG. In addition, the same code | symbol is attached | subjected to each part and circuit which have the function similar to 1st embodiment shown in FIG. 4, and description is abbreviate | omitted.

  In FIG. 12, the external power supply input unit 1201 converts an alternating voltage supplied from the external power supply into a direct current and sends the direct current to the current control unit 1202. The external power input unit 1201 may be outside the image reading apparatus such as an AC adapter. Further, the power may be supplied from the host PC via a universal serial bus (USB) or the like.

  The external power input unit 1201 includes an external input terminal (not shown), and supplies power to the CIS 401, the amplifier circuit 402, the A / D converter 403, the light source lighting unit 405, and a load (not shown) in the image reading apparatus. To do. In addition, a path for transmitting power from the storage element 1203 to each load is directly connected, and the charging voltage value of the storage element 1203 is supplied to the load as it is.

  In addition, the electric storage element 1203 is provided with, for example, an electric double layer capacitor having high charge / discharge durability. Note that the power storage element 1203 can temporarily store the power supplied from the external power supply input unit 1201.

  The current control unit 1202 can be controlled so that a certain current flows to the power storage element 1203. The voltage detection unit 1204 measures the power stored in the power storage element 1203 by monitoring the voltage of the power storage element 1203.

  Here, the operation of the image reading apparatus according to the fifth embodiment will be described with reference to the flowchart shown in FIG. Note that the processing in S1301 to S1313 and S1317 to S1320 shown in FIG. 13 is the same as the processing in S501 to S513 and S515 to S518 shown in FIG. 5 described in the first embodiment, and a description thereof will be omitted.

  In S1306, when the reading operation control unit 404 determines that there is no free space in the buffer memory 407, the reading operation control unit 404 shifts to the intermittent reading mode, and instructs the stop of the feed motor 3 (S1312) as in the first embodiment. Are all stopped (S1313). Accordingly, the CIS 401, the amplifier circuit 402, the A / D conversion unit 403, and the light source lighting unit 405 are not operated while the reading operation is stopped, and the power consumption is suppressed, so that the load connected to the power storage element 1203 is reduced. become.

  Therefore, in S1314, the current control unit 1202 controls the current so that the power storage element 1203 is charged with the power corresponding to the decrease in the operation described above, and starts charging. In step S1315, charging is continued until the free space is available in the buffer memory 407. If free space is available, the process proceeds to step S1316, and the control for charging the power storage element 1203 is terminated. Note that, when the voltage detection unit 1204 detects that the storage element 1203 has reached a certain voltage, the charging may be completed.

  According to the fifth embodiment, when the reading operation is stopped and the load is lightened, it is possible to use the external power input unit having a low supply capability by controlling the storage element 1203 to be charged. .

  The reading operation may be stopped not only when the buffer memory 407 has run out of space, but also when the voltage of the power storage element 1203 becomes low. Accordingly, when the remaining power of the power storage element 1203 decreases, the reading operation is stopped and the power storage element 1203 can be charged.

  Further, as in the third embodiment, an analog signal monitoring unit 801 may be provided, and the analog signal monitoring unit 801 may monitor whether or not the CIS 401 is in a normal operation state when the reading operation is resumed.

[Sixth embodiment]
Next, a sixth embodiment according to the present invention will be described in detail with reference to the drawings. In the sixth embodiment, as shown in FIG. 14, the power control unit 601 of the second embodiment is added to the configuration of the image reading apparatus in the fifth embodiment shown in FIG.

  Here, the operation of the image reading apparatus according to the sixth embodiment will be described with reference to the flowchart shown in FIG. The processes in S1501 to S1513, S1515 to S1517, and S1519 to S1522 shown in FIG. 15 are the same as the processes in S1301 to S1313, S1314 to S1316, and S1317 to S1320 shown in FIG. 13 described in the fifth embodiment. is there.

  In S1506, when the reading operation control unit 404 determines that there is no free space in the buffer memory 407, the reading operation control unit 404 shifts to the intermittent reading mode, and stops the feed motor 3 (S1512) and stops the drive signal (S1313). Next, in S1514, as in the second embodiment, the reading operation control unit 404 supplies power to the power control unit 601 to the CIS 401, the amplifier circuit 402, the A / D conversion unit 403, and the light source lighting unit 405. To turn off.

  In response to this instruction, the power control unit 601 turns off the power supply to each instructed unit and circuit. Accordingly, since power to the CIS 401, the amplification circuit 402, the A / D conversion unit 403, and the light source lighting unit 405 is turned off while the reading operation is stopped, power consumption is suppressed, and the load connected to the power storage element 1203 is reduced. Will be reduced.

  Therefore, in S1515, as in the fifth embodiment, the current control unit 1202 controls the current so as to charge the power storage element 1203 by the amount reduced by the above-described operation stop, and starts charging. In step S1516, charging is continued until the free space is available in the buffer memory 407. If free space is available, the process proceeds to step S1517, and the control for charging the power storage element 1203 is terminated. Note that, when the voltage detection unit 1204 detects that the storage element 1203 has reached a certain voltage, the charging may be completed.

  In step S <b> 1518, the reading operation control unit 404 instructs the power supply control unit 601 to turn on the power. In response to this instruction, the power control unit 601 resumes power supply to the CIS 401, the amplifier circuit 402, the A / D conversion unit 403, and the light source lighting unit 405.

  According to the sixth embodiment, in addition to the effect in the fifth embodiment described above, the effect in the second embodiment can also be obtained.

  Further, as in the fourth embodiment, an analog signal monitoring unit 801 may be provided, and the analog signal monitoring unit 801 may monitor whether or not the CIS 401 is in a normal operation state when the reading operation is resumed.

[Other Embodiments]
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

Claims (7)

An image reading device that irradiates a document with light from a light source, photoelectrically converts reflected light from the document, and reads an image of the document,
Having an intermittent reading mode for temporarily interrupting a reading operation of reading the image of the original;
Monitoring means for monitoring the analog signal converted by the photoelectric conversion;
When shifting to the intermittent reading mode under specific conditions during the reading operation, the signal to the drive system for moving the document, the signal to the reading system for reading an image by the photoelectric conversion, and the light source Stop means for stopping the supply of the signal to be lit,
When returning from the intermittent reading mode, the supply of signals to the drive system in a stopped state by the stop means, a signal to the reading system subjected sheet, said analog signal is equal to or less than a predetermined value Is detected by the monitoring means, resuming means for supplying a signal for turning on the light source and a signal to the drive system to resume the reading operation;
An image reading apparatus comprising: A power control means for controlling power supply to the reading system and the light source;
The power control means stops supplying power to the reading system and the light source when shifting to the intermittent reading mode, and supplies power to the reading system and the light source when returning from the intermittent reading mode. The image reading apparatus according to claim 1, wherein the image reading apparatus restarts. When returning from the intermittent reading mode, the signal to the reading system is supplied in a state where the supply of the signal to the driving system and the signal to turn on the light source is stopped by the stopping unit, and the analog signal is predetermined. 2. The reading operation is resumed by supplying a signal for turning on the light source and a signal to the driving system by the resuming unit when the monitoring unit detects that the value is lower than a value. 3. The image reading apparatus according to 2. A storage element that performs charging / discharging with power from an external power source and supplies power to the reading system and the light source;
Control means for controlling the power storage element to charge power when the intermittent reading mode is entered;
The image reading apparatus according to claim 1, further comprising:   The reading system converts an analog signal converted by the photoelectric conversion into digital data, and the restarting unit determines that the photoelectric conversion is in a normal operation state based on the digital data. Item 3. The image reading apparatus according to Item 1 or 2. A method for controlling an image reading apparatus that irradiates a document with light from a light source, photoelectrically converts reflected light from the document, and reads an image of the document.
Having an intermittent reading mode for temporarily interrupting a reading operation of reading the image of the original;
A monitoring step of monitoring an analog signal converted by the photoelectric conversion;
When the stopping unit is performing the reading operation and the mode is shifted to the intermittent reading mode due to a specific condition, a signal to the driving system for moving the document and a signal to the reading system for reading an image by the photoelectric conversion And a stopping step of stopping supply of a signal for turning on the light source,
Resuming means, when returning from the intermittent reading mode, the state in which the supply and stop of the signal to the drive system by stopping step, a signal to the reading system subjected sheet, the analog signal is below a predetermined value When it is detected by the monitoring step, a restarting step of restarting the reading operation by supplying a signal for turning on the light source and a signal to the drive system,
An image reading apparatus control method comprising:   A program for causing a computer to function as each unit of the image reading apparatus according to any one of claims 1 to 5.

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