Image reading device and image forming apparatus

Abstract

To provide an image reading device and an image forming device that reduce downtime during which users cannot use the device. [Solution] The image reading device includes at least one of an image sensor for reading an image and a light source for irradiating light, a carriage that scans back and forth in a one-dimensional direction, a position sensor for detecting the reference position of the carriage, a motor for driving the carriage, a motor drive device for generating a clock signal for the motor, and a motor driver for driving the motor according to the generated clock signal. If the motor drive device determines that there is an abnormality in the carriage based on the number of pulses counted by a pulse counter that counts the number of pulses of the generated clock signal and the logic of the position sensor, it performs a rescan operation, which is a scanning operation of the carriage in the direction in which the logic of the position sensor changes again, and performs a back-and-forth scanning of the carriage again for a travel distance equal to or greater than when the previous scanning operation of the carriage was performed normally.

Description

Technical Field

[0001] The present invention relates to an image reading apparatus and an image forming apparatus.

Background Art

[0002] In an image reading apparatus (scanner), there is a position sensor for detecting a reference position of a carriage that performs scanning during document reading, counts the number of pulses of the carriage to be scanned, and checks the on or off of the position sensor at a position where the carriage has moved by an arbitrary number of pulses to detect the presence or absence of an abnormality in the drive of the carriage (see Patent Document 1).

Summary of the Invention

Problems to be Solved by the Invention

[0003] However, the method for detecting an abnormality in the drive of the carriage can immediately notify the user of the abnormality when an abnormality occurs during the drive of the carriage. For example, when an error occurs during the reading of a reference white plate, even for an abnormality such as detuning that can be recovered, the abnormality is notified, the image reading apparatus is forcibly stopped and recovered, so the power of the image reading apparatus is turned off and on, and restarted, resulting in a long downtime (the time when the image reading apparatus cannot be used) for the user.

[0004] The present invention has been made in view of the above, and an object thereof is to provide an image reading apparatus and an image forming apparatus that can shorten the downtime during which the user cannot use the image reading apparatus.

Means for Solving the Problems

[0005] To solve the above-mentioned problems and achieve the objective, the present invention comprises an image sensor for reading an image of an object, a light source for irradiating the object with light, a carriage comprising at least one of the image sensor and the light source and performing a reciprocating scan in a one-dimensional direction, a position sensor for detecting the reference position of the carriage, a motor for driving the carriage, a motor drive device for generating a clock signal for the motor, a motor driver for outputting a motor drive signal to the motor to drive the motor according to the clock signal generated by the motor drive device, and a pulse counter for counting the number of pulses of the clock signal generated by the motor drive device. If the motor drive device determines that there is an abnormality in the carriage based on the number of pulses counted by the pulse counter and the logic of the position sensor, it performs a rescan operation, which is a scanning operation of the carriage, in the direction in which the logic of the position sensor changes, and the rescan operation performs a reciprocating scan of the carriage again with a travel distance equal to or greater than that when the previous scanning operation of the carriage was performed normally. [Effects of the Invention]

[0006] The present invention has the effect of reducing downtime during which users are unable to use the image reading device. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is an explanatory diagram of an image reading device (scanner) according to this embodiment. [Figure 2] Figure 2 is a diagram illustrating an example of the functional block of the image reading device according to this embodiment. [Figure 3] Figure 3 is an explanatory diagram of the carriage operation of the image reading device (scanner) according to this embodiment. [Figure 4] Figure 4 shows a method for determining errors in the operation of the carriage in the image reading device according to this embodiment. [Figure 5]Figure 5 shows an example of the error detection process for the carriage during the document scanning operation shown in Figure 4. [Figure 6A] Figure 6A is a flowchart showing an example of the error detection process for the carriage during document scanning according to this embodiment. [Figure 6B] Figure 6B is a flowchart showing an example of the retry process flow during document scanning according to this embodiment. [Figure 7A] Figure 7A is a flowchart showing an example of the error detection process for the carriage during the reference whiteboard reading operation according to this embodiment. [Figure 7B] Figure 7B is a flowchart showing an example of the retry process flow during the reference whiteboard reading operation according to this embodiment. [Figure 8] Figure 8 shows an example of the error log screen display according to this embodiment. [Figure 9] Figure 9 shows an example of the control panel screen according to this embodiment. [Figure 10] Figure 10 is a diagram illustrating an example of the effects according to this embodiment. [Figure 11] Figure 11 shows an example of an image forming apparatus equipped with an image reading device according to this embodiment. [Modes for carrying out the invention]

[0008] Embodiments of the image reading device and image forming device will be described in detail below with reference to the attached drawings.

[0009] Figure 1 is an explanatory diagram of an image reading device (scanner) according to this embodiment. The image reading device 101 is a scanner device mounted on an image forming device such as a digital copier, digital multifunction printer, or facsimile machine, or a standalone scanner device. That is, the image reading device 101 may have at least one of the following functions: copy printing, scanner transmission, and fax transmission. The image reading device 101 illuminates the original document with light emitted from the light source 3, receives the reflected light from the original document with the image sensor substrate 4, processes the signal output from the image sensor substrate 4, and reads the image data of the original document. That is, the image sensor substrate 4 is an example of an image sensor that reads the image of an object such as an original document. The light source 3 is an example of a light source that irradiates light onto an object.

[0010] As shown in Figure 1, the carriage 2 includes a light source 3 for exposure of the original document, an image sensor board 4 that receives reflected light from the light source 3 and converts it into a signal, and a reflective mirror 5 that sends the reflected light from the light source 3 to the image sensor board 4. The image sensor board 4 also has components such as a lens for forming an image and an AFE that converts the analog signal received by the image sensor board 4 into a digital signal.

[0011] The configuration of this carriage 2 can be either a reduction optical system using a CCD (Charge Coupled Device) sensor or a contact optical system using a CIS (Contact Image Sensor), but there is no particular limitation here. Also, in the image reading device 101 shown in Figure 1, the carriage 2 is an integrated unit in which components such as the light source 3, image sensor substrate 4, and reflective mirror 5 are assembled, but there is also a method in which the image sensor substrate 4 is fixed and only the light source 3 and reflective mirror 5 are scanned as the carriage 2. In other words, the carriage 2 only needs to include at least one of the image sensor substrate 4 and the light source 3.

[0012] Furthermore, the image reading device 101 places the original document on the contact glass 11 and causes the carriage 2 to reciprocate in the sub-scanning direction (an example of a one-dimensional direction). When reading an image using flatbed scanning, the image reading device 101 confirms the position of the carriage 2 using the position sensor 8, and the drive motor 6 rotates, causing the carriage 2 connected to the drive belt 7 to scan. The device reads the original document placed on the contact glass 11 and the reference whiteboard 10, which is used to correct various variations caused by the reading optical system, etc., and then the carriage 2 returns to its initial position. Here, the position sensor 8 is an example of a position sensor that detects the initial carriage position A (see Figure 3), which is an example of a reference position for the carriage 2. The reference whiteboard 10 is an example of a reference whiteboard used to adjust the image reading density by the image sensor substrate 4.

[0013] The image reading device 101 has an automatic document feeder (ADF) mounted on its upper part, and this ADF 102 is connected to the contact glass 11 via hinges or the like so that it can be opened and closed. The ADF 102 has a document tray that serves as a document tray on which a stack of multiple documents can be placed. The image reading device 101 also has a separation and feeding means, including a document feeding roller, that separates documents one by one from the stack of documents placed on the document tray and automatically feeds and transports them toward the document reading glass 9. The image reading device 101 may also have a configuration in which another sensor is installed on the ADF 102 to read both sides of a document in a single document transport. In this way, the image reading device 101 performs the operation of reading documents.

[0014] Figure 2 is a diagram illustrating an example of the functional block of the image reading device according to this embodiment. The image reading device 101 according to this embodiment has a scanner unit 201 and a control board 202, as shown in Figure 2. Inside the scanner unit 201 are a drive motor 6, a position sensor 8, a light source 3, and an image sensor board 4, as shown in Figure 1. A separate control board 202 is provided as an input / output interface for various signals to the scanner unit 201. The control board 202 may be located inside the image reading device 101, or it may be located separately on the main body side of a digital multifunction printer or copier, etc.

[0015] The drive motor 6 is an example of a motor that drives the carriage 2. The motor drive device 202a in the control board 202 inputs input signals such as a clock signal, enable signal, direction signal, and current adjustment signal to the motor driver 202b. In other words, the motor drive device 202a is an example of a motor drive device that generates the clock signal for the drive motor 6. The motor driver 202b outputs a motor drive signal that controls the speed, rotation direction, and drive current for operating the drive motor 6 according to each input signal. In other words, the motor driver 202b is an example of a motor driver that receives a clock signal from the motor drive device 202a and outputs a motor drive signal to drive the drive motor 6 according to that clock signal. Upon receiving this motor drive signal, the drive motor 6 rotates and controls the carriage 2.

[0016] In addition, the motor drive device 202a is equipped with a pulse counter 203 that counts the number of times a clock signal is input, and an interrupt detector 204 that generates an interrupt at an arbitrary distance. The pulse counter 203 is an example of a pulse counter that counts the number of pulses of the clock signal generated by the motor drive device 202a. The interrupt detector 204 is an example of an interrupt detector that generates an interrupt when the number of pulses (counter value) counted by the pulse counter 203 reaches an arbitrarily set number of pulses. Then, the motor drive device 202a determines and realizes the stop position of the carriage 2 and the detection of abnormalities in the operation of the carriage 2 by means of the interrupt detector 204 and the counting of the number of pulses by the pulse counter 203. The method of detailed abnormality detection will be described later.

[0017] The position sensor 8 often uses a general transmissive or reflective photosensor. Depending on the position of the carriage 2, the output of the position sensor 8 switches between Low and High, and the sensor detection unit 202c receives the logic to determine the location of the carriage 2.

[0018] The light source 3 often uses an LED (Light Emitting Diode) or a xenon lamp. It receives the light source ON / OFF signal from the light source control unit 205, turns on and off the light source 3, and inputs the reflected light to the image sensor substrate 4. The image sensor in the image sensor substrate 4 receives the reflected light, converts it from analog to digital within the image sensor substrate 4, transmits the reading level to the subsequent image processing unit 206, performs correction of various images, and outputs it as a read image.

[0019] In the present embodiment, the operation of the carriage 2 by the drive motor 6 is the detection target of the position sensor 8, and the details of the image generation method of the light source 3 and the image sensor substrate 4 are not mentioned here. In addition, the control board 202 is equipped with a non-volatile memory 207 so that various setting values, the usage status of devices, etc. can be saved. For example, information at the time of an abnormality can also be saved in the memory 207.

[0020] Figure 3 is an explanatory diagram of the carriage operation of the image reading device (scanner) according to this embodiment. Here, we will explain three general operations of the carriage 2 in the scanner unit 201 shown in Figure 2. The first operation, the home position movement operation, is the operation to return the carriage 2 to the carriage initial position A. In the reference whiteboard reading operation and document reading operation described below, if the carriage initial position A is misaligned, the values ​​on the reference whiteboard 10 may not be read correctly, or the document may be misread. Therefore, before these operations, the home position movement operation must always be performed to return the carriage 2 to the carriage initial position A.

[0021] In Figure 3, initially, when carriage 2 is in carriage initial position A, it is moved to position sensor OFF determination position b where position sensor 8 is turned OFF, then moved in the direction that turns position sensor 8 ON, and returned to carriage initial position A. The carriage initial position A is set in advance as a system by moving a fixed amount from position sensor ON position B, which is the position where position sensor 8 is turned ON, and this serves as the reference position for all movements of carriage 2.

[0022] Furthermore, when carriage 2 is to the right of position sensor OFF detection position b and the home position movement operation is performed, it performs only a return movement, not a round trip movement. As explained above, after position sensor 8 turns ON at position sensor ON position B, carriage 2 moves by a fixed amount and returns to carriage initial position A.

[0023] The second reference whiteboard reading operation involves moving carriage 2 directly below reference whiteboard 10 to acquire the whiteboard level (whiteboard data) and returning the carriage to its initial position A. The whiteboard level is read as a reference value for adjusting the reading level gain, or used as a reference level for shading correction to correct for uneven density in the original document.

[0024] During the document reading operation described below, the carriage 2 scans and reads the whiteboard level as it passes over the reference whiteboard 10 before reading the document. However, in other cases, such as when adjusting the light intensity and gain when the system is powered on, or when reading the reference whiteboard 10 during continuous reading of the ADF 102, the carriage 2 is moved to the reference whiteboard reading position C, as shown in the figure above, and the operation to read the reference whiteboard 10 is performed.

[0025] The third document scanning operation involves setting the document on the contact glass 11 and scanning it. The carriage 2 moves from its initial position A, passes through the reference whiteboard 10, and travels within a range corresponding to the document length (in this case, the range from the document scanning start position D to the document scanning end position E). After acquiring the document data, the carriage returns to its initial position A. The document scanning end position E may be variable depending on the document length. In this case, the whiteboard level at the reference whiteboard scanning position C is acquired by the carriage 2 while scanning, and a reference level for shading correction is obtained.

[0026] The above describes the operation of the three main carriages 2, and whether or not there is an abnormality in the operation of each carriage 2 is determined by the ON or OFF logic of the position sensor 8.

[0027] Figure 4 shows a method for determining errors in the operation of the carriage in the image reading device according to this embodiment. During the document reading operation shown in Figure 3, the carriage 2 performs a reciprocal scan. Specifically, during the document reading operation, the motor drive device 202a starts a forward scan of the carriage 2 from the initial carriage position A, and when it passes the position sensor ON position B, the position sensor 8 turns OFF. After that, the motor drive device 202a reads the reference whiteboard 10, which is the reference level for reading, starts reading the document at the document reading start position D, and finishes reading the document at the document reading end position E. After reading is complete, the motor drive device 202a performs a return scan (return operation) from the document reading end position E back to the initial carriage position A, returning the carriage 2 to the initial carriage position A.

[0028] Here, we will explain an example of how carriage 2 can detect errors. The motor drive device 202a has a predetermined count value for the pulse count of the drive motor 6, which is pre-programmed into the control software so that a judgment interrupt is performed by the interrupt detector 204 at the position sensor ON judgment position a and the position sensor OFF judgment position b. When carriage 2 is scanning in the forward direction (forward direction operation), it reaches the position sensor ON judgment position a immediately after the start of scanning. At this point, the motor drive device 202a determines that it is normal if the position sensor 8 is ON, and if the position sensor 8 is OFF, it considers it abnormal, stops the operation of carriage 2, and notifies the user of the error (error pattern (1)).

[0029] When carriage 2 successfully passes position sensor ON determination position a, it reaches position sensor OFF determination position b. Here, if the motor drive device 202a passes position sensor 8 and reaches position sensor OFF determination position b, it is considered normal if position sensor 8 turns OFF, but if position sensor 8 is ON, it is considered abnormal, stops the operation of carriage 2, and notifies the user of an error (error pattern (2)).

[0030] Similarly, during the return scan (return operation), when the motor drive device 202a returns to the position sensor OFF determination position b, and has not yet reached the position sensor 8, the position sensor 8 should be OFF. However, if the position sensor 8 is ON at the position sensor OFF determination position b, this is considered an abnormality, the operation of the carriage 2 is stopped, and an error notification is sent to the user (error pattern (3)).

[0031] The motor drive device 202a then checks that when the carriage 2 passes through the position sensor OFF determination position b normally and returns to the position sensor ON determination position a, the position sensor 8 should turn ON. However, if the position sensor 8 is OFF, the motor drive device 202a considers this an abnormality, stops the operation of the carriage 2, and notifies the user of the error (error pattern (4)). The motor drive device 202a performs the above check (detection of abnormalities in the operation of the carriage 2), and if all passes are normal, it returns the carriage 2 to the initial carriage position A and completes the operation.

[0032] Based on these four error patterns, the system determines whether carriage 2 is operating normally and often takes measures to notify the user if an abnormality occurs. Although Figure 4 describes the document reading operation shown in Figure 3, the above can also be applied to the home position movement operation and reference whiteboard reading operation shown in Figure 3. Various factors can cause an abnormality when determining the position sensor 8, including a malfunction of the position sensor 8 itself, a malfunction of the drive motor 6, a malfunction of the device that outputs the motor operation signal (motor driver 202b), a disconnection of the harness connecting the drive motor 6, and damage to the mechanical parts that operate the drive motor 6 (gears and belts).

[0033] Figure 5 shows an example of the error detection process flow for the carriage during the document reading operation shown in Figure 4. First, the motor drive device 202a moves the carriage 2 to the home position, which is the initial carriage position A (step S501). The home position movement shown in step S501 is the operation of returning the carriage 2 to the initial carriage position A, as explained in Figure 3, and the internal flow explanation is omitted here. Next, the motor drive device 202a starts driving the drive motor 6 and performs the forward scan (forward operation) of the carriage 2 (step S502). Next, the motor drive device 202a determines whether the position sensor 8 is ON at the position sensor ON determination position a (step S503). If the position sensor 8 is OFF at the position sensor ON determination position a (step S503: No), the motor drive device 202a stops driving the drive motor 6 (step S514), detects an abnormality in the carriage 2 (error pattern (1)) and issues an error notification (step S515).

[0034] If the position sensor 8 is ON at position sensor ON determination position a (step S503: Yes), the motor drive device 202a determines whether the position sensor 8 is OFF at position sensor OFF determination position b (step S504). If the position sensor 8 is ON at position sensor OFF determination position b (step S504: No), the motor drive device 202a stops driving the drive motor 6 (step S514), detects an abnormality in the carriage 2 (error pattern (2)) and issues an error notification (step S515).

[0035] If the position sensor 8 is OFF at position sensor OFF determination position b (step S504: Yes), the motor drive device 202a moves the carriage 2 to the reference whiteboard reading position C and acquires whiteboard data (step S505). Next, the motor drive device 202a determines whether the acquired whiteboard data is within the threshold range (step S506). If the acquired whiteboard data is at an abnormal level outside the threshold range (step S506: No), the motor drive device 202a stops the drive motor 6 at the reference whiteboard error carriage stop position c (step S516), detects the abnormality in the whiteboard data and issues an error notification (step S517).

[0036] If the acquired whiteboard data is within the threshold range and at a normal level (Step S506: Yes), the motor drive device 202a moves the carriage 2 from the document reading start position D to the document reading end position E to acquire the document data (image) (Step S507). Then, the motor drive device 202a stops the drive of the drive motor 6 at the document reading end position E (Step S508). Next, the motor drive device 202a starts the drive of the drive motor 6 and performs the return scan (return operation) of the carriage 2 (Step S509).

[0037] Next, the motor drive device 202a determines whether the position sensor 8 is turned OFF at the position sensor OFF determination position b (step S510). If the position sensor 8 is ON at the position sensor OFF determination position b (step S510: No), the motor drive device 202a stops driving the drive motor 6 (step S514), detects an abnormality in the carriage 2 (error pattern (3)) and issues an error notification (step S515).

[0038] If the position sensor 8 is OFF at position sensor OFF determination position b (step S510: Yes), the motor drive device 202a determines whether the position sensor 8 is ON at position sensor ON determination position a (step S511). If the position sensor 8 is OFF at position sensor ON determination position a (step S511: No), the motor drive device 202a stops driving the drive motor 6 (step S514), detects an abnormality in the carriage 2 (error pattern (4)) and issues an error notification (step S515).

[0039] If the position sensor 8 is ON at position sensor ON determination position a (step S511: Yes), the motor drive device 202a stops driving the drive motor 6 at the initial carriage position A (step S512) and completes the operation of the carriage 2 normally (step S513).

[0040] As explained in Figure 4, during the forward and return movements of carriage 2, error detection is performed at position sensor ON determination position a and position sensor OFF determination position b, with error patterns (1) to (4) being determined (steps S503, S504, S510, S511). Normally, if no error occurs, during the forward movement, carriage 2 acquires whiteboard data at the reference whiteboard reading position C while the carriage is moving, acquires document data from the document reading start position D to the document reading end position E, stops at the document reading end position E, and then returns to the carriage initial position A, which is the reference position, during the return movement, completing the process normally (steps S501 to S513).

[0041] If carriage 2 is determined to have an error in any of the error patterns (1) to (4), the drive of the drive motor 6 is stopped and an error notification is issued (steps S514, S515). At this time, in order to inform the user of the abnormality, an error notification will be displayed on the control panel screen, prompting the user to turn the machine's power OFF and then ON again, or to contact a service technician. Some machines are equipped with a reboot function that automatically turns the machine's power OFF and then ON to restore the system.

[0042] There is also a branch that determines whether the whiteboard data is within a threshold range (step S506). This determines whether the whiteboard data of the reference whiteboard 10 read when the carriage 2 passes the reference whiteboard reading position C is normal. If it is an abnormal value, the drive motor 6 is stopped and the user is notified of the abnormality (steps S516, S517). In this case, since the whiteboard data is acquired while the carriage 2 is in motion, there is a time lag to decelerate and stop the carriage 2 before it stops. Therefore, the stopping position of the carriage 2 is not the reference whiteboard reading position C shown in Figure 4, but the reference whiteboard error carriage stopping position c.

[0043] Possible causes of abnormal reference whiteboard data include an abnormality occurring after carriage 2 passes position sensor OFF detection position b during forward movement, preventing it from reaching below reference whiteboard 10 properly and resulting in data being read at a location other than directly below reference whiteboard 10, or a malfunction in the optical system, such as light source 3 and image sensor.

[0044] The flowchart shown in Figure 5 illustrates the typical error detection process during document scanning. However, a challenge here is that even for temporary errors caused by external factors (such as external impacts) that do not require repair by a service technician, the user may be forced to turn the machine back on or contact a service technician due to the error notification, resulting in downtime and causing stress.

[0045] Figure 6A is a flowchart showing an example of the error detection process for the carriage during document reading according to this embodiment. In the following description, the same process as in Figure 5 will not be explained. In this embodiment, if the position sensor 8 is OFF at position sensor ON determination position a (step S503: No), and if the position sensor 8 is ON at position sensor OFF determination position b (step S504: No), the motor drive device 202a sets the forward path abnormality flag, which indicates an abnormality in the forward path scanning of the carriage 2, to 1 (step S601). After that, the motor drive device 202a stops driving the drive motor 6 (step S514) and then executes a retry process (step S602).

[0046] Furthermore, in this embodiment, if the acquired whiteboard data is at an abnormal level outside the threshold range (step S506: No), the motor drive device 202a stops the drive motor 6 at the reference whiteboard error carriage stop position c (step S516), resets the pulse counter 203 (step S603), and moves the carriage 2 to the carriage initial position A (step S604). Next, the motor drive device 202a determines whether the number of pulses corresponding to the distance from the reference whiteboard error carriage stop position c to the carriage initial position A matches the number of pulses (counter value) from the pulse counter 203 (step S605).

[0047] Then, if the number of pulses corresponding to the distance from the reference whiteboard error carriage stop position c to the initial carriage position A matches the number of pulses (counter value) from the pulse counter 203 (step S605: Yes), the motor drive device 202a determines that the drive motor 6 is operating normally and notifies of an abnormality in the whiteboard data (step S607). On the other hand, if the number of pulses corresponding to the distance from the reference whiteboard error carriage stop position c to the initial carriage position A does not match the number of pulses (counter value) from the pulse counter 203 (step S605: No), the motor drive device 202a sets the forward path abnormality flag to 1, indicating an abnormality in the forward path scanning of the carriage 2 (step S606).

[0048] Compared to the general flowchart shown in Figure 5, the normal operation when no abnormality occurs in carriage 2 is exactly the same (steps S501 to S513). The difference from the flowchart shown in Figure 5 is that, when comparing the document scanning operation flowchart shown in Figure 6A, even if an error is detected in error patterns (1) to (4), the system does not immediately notify the user of the error. Instead, it enters the retry process flowchart shown in Figure 6B and performs the document scanning operation again, so that an error notification is not issued for a single error (step S602).

[0049] Figure 6B is a flowchart showing an example of the retry process flow during document scanning according to this embodiment. In the following description, the same process as in Figure 5 will not be explained. During the retry process for document scanning, if the acquired whiteboard data is within the threshold range (step S506: Yes), the motor drive device 202a determines whether the forward path abnormality flag is 1 or not (step S608). If the forward path abnormality flag is not 1 (step S608: No), the motor drive device 202a proceeds to step S508 and detects an abnormality in the carriage 2 on the return path. On the other hand, if the forward path abnormality flag is 1 (step S608: Yes), the motor drive device 202a moves the carriage 2 from the document scanning start position D to the document scanning end position E and acquires the document data (image) (step S507). After that, the motor drive device 202a stops driving the drive motor 6 at the document scanning end position E (step S508).

[0050] Furthermore, if the position sensor 8 is ON at position sensor ON determination position a (step S511: Yes), the motor drive device 202a stops driving the drive motor 6 at the carriage initial position A (step S512), clears the forward path abnormality flag (step S609), and then completes the operation of the carriage 2 normally (step S513).

[0051] The retry process flowchart shown in Figure 6B is designed to perform the document scanning operation again, which is the same as the general flowchart shown in Figure 5. However, steps S608 and S609 in Figure 6B are added. This allows the system to attempt recovery through the retry process even if a carriage error is initially detected, and if no error occurs, the document scanning operation can be performed. In other words, the motor drive device 202a determines whether there is an abnormality in the carriage 2 based on the number of pulses counted by the pulse counter 203 and the logic of the position sensor 8. If an abnormality is detected in the carriage 2, it performs a rescan operation, which is a scanning operation of the carriage 2, in the direction in which the logic of the position sensor 8 changes. Here, the rescan operation performs a back-and-forth scan of the carriage 2 again, traveling a distance equal to or greater than when the previous scanning operation of the carriage 2 was performed normally. Furthermore, the logic of the position sensor 8 may also be that it changes to ON when it detects that the carriage 2 is at the initial carriage position A, and changes to OFF when it detects that the carriage 2 has moved from the initial carriage position A.

[0052] As a result, in the method for detecting abnormalities in the carriage 2's drive, even if an abnormality occurs when scanning a document or the reference whiteboard 10, it is possible to distinguish whether the abnormality is in the optical system or the carriage 2's drive. Even if it is determined that the carriage 2's drive is abnormal, if the abnormality is recoverable, the system automatically determines whether recovery is possible without turning the image reading device 101's power off and on again, thereby reducing the downtime during which the user cannot use the image reading device 101.

[0053] In the document reading operation flowchart shown in Figure 6A, the process of determining whether the whiteboard data is within the threshold range (step S506) includes an additional step (steps S605 to S607) to determine whether the abnormality is in the carriage 2 or the optical system, even if an abnormality level is detected. The method for determining whether the abnormality is in the carriage 2 or the optical system is as follows: If there is an abnormality in the whiteboard data, the drive motor 6 is stopped at the reference whiteboard error carriage stop position c in Figure 4, the pulse counter 203 of the drive motor 6 is reset, and the carriage pulse count is performed until it returns to the home position (initial carriage position A). Since the distance from the reference whiteboard error carriage stop position c to the initial carriage position A is fixed, the ideal value for the number of pulses is known. Therefore, the number of pulses when the carriage 2 is actually returned is counted and compared with the ideal value. If they match, it can be determined that there is no particular problem with the carriage 2, and the abnormality is determined to be in the optical system, and the user is immediately notified of the error. However, if the pulse count does not match, it is determined that there is an abnormality in carriage 2, and the flowchart shown in Figure 6B initiates a retry process, which allows for recovery in the event of a sudden malfunction.

[0054] In other words, when reading the reference whiteboard 10, the motor drive device 202a, based on the whiteboard data of the reference whiteboard 10 (an example of the reading level), determines that the reference whiteboard 10 is at an abnormal level. If this is determined, it compares the number of pulses when returning the carriage 2 to its initial position A with the ideal value. If the carriage 2 is deemed to be abnormal, it performs a reciprocal scan of the carriage 2 again to determine if the carriage 2 is abnormal. This makes it possible to distinguish between an optical system abnormality and a carriage 2 abnormality, further reducing user downtime.

[0055] Furthermore, when an error occurs in carriage 2 due to error patterns (1) and (2), or an abnormality in the reference whiteboard data, a flag called a forward path abnormality flag is set (steps S601 and S607). This is to determine whether the abnormality in carriage 2 occurred during the forward path operation or the return path operation, and to decide whether or not to acquire the original data again during the retry process. When an error is detected in the forward path of carriage 2, the flowchart shown in Figure 6A has not yet acquired the original data. If there is no error in the retry process shown in Figure 6B, the original data is acquired at this point, allowing the user to perform the scanning operation without having to go through the original reading procedure again.

[0056] If an error is detected on the return journey of carriage 2 in error patterns (3) and (4), and the document reading operation is performed again, the acquisition of the document data will have already been completed in the flowchart shown in Figure 6A, and the system will have performed processing for scanning or copying, and in the case of copying, the copied image will have been generated. Generally, copies are often charged per page, so if the document data is acquired again in the flowchart shown in Figure 6B, there is a risk of unintentionally incurring charges. Therefore, to distinguish between abnormalities in the return journey operation of carriage 2, a branch (step S608) is deliberately set up based on whether the outward journey abnormality flag is 1 or not, and the flowchart is designed so that document data is not generated. When the operation is completed without problems in the retry process shown in Figure 6B, the outward journey abnormality flag is cleared (step S609).

[0057] In other words, the motor drive device 202a detects any abnormalities in the carriage 2 during the document scanning operation. If an abnormality is detected during the forward scan of the carriage 2, the device performs image scanning again when scanning the carriage 2 back and forth. If an abnormality is detected during the return scan of the carriage 2, the device does not perform image scanning again when scanning the carriage 2 back and forth. This allows the scanning operation to be performed without requiring the user to perform any further operations, and also prevents user charges by not performing scanning processing for errors that occur when scanning a document has already been performed.

[0058] Figure 7A is a flowchart showing an example of the error detection process flow for the carriage during the reference whiteboard reading operation according to this embodiment. Figure 7B is a flowchart showing an example of the retry process flow during the reference whiteboard reading operation according to this embodiment. In the following description, the same processes as those in Figures 5, 6A, and 6B will not be explained. As explained in the explanatory diagram of the carriage operation in Figure 3, the operation of the carriage 2 includes the operation of reading whiteboard data and a round trip operation to directly below the reference whiteboard 10 (reference whiteboard reading position C). In this embodiment, in particular, retry processing can be performed not only for the document reading operation shown in Figures 6A and 6B, but also for the scanning operation of the carriage 2 when the carriage 2 straddles the position sensor 8.

[0059] As shown in Figure 7A, during the reference whiteboard reading operation, if the position sensor 8 is OFF at position sensor OFF determination position b (step S504: Yes), the motor drive device 202a moves the carriage 2 to the reference whiteboard reading position C and stops the carriage 2 (step S701), and then proceeds to step S505. Also, if the acquired whiteboard data is at an abnormal level outside the threshold range (step S506: No), the motor drive device 202a proceeds to step S603 and resets the pulse counter 203.

[0060] Furthermore, as shown in Figure 7B, during the retry process when reading the reference whiteboard, if the acquired whiteboard data is at an abnormal level outside the threshold range (step S506: No), the motor drive device 202a proceeds to step S517 without stopping the carriage 2 at the reference whiteboard error carriage stop position c.

[0061] The only difference between Figures 6A and 6B and Figures 7A and 7B is that document scanning is not performed, and if the whiteboard data is outside the threshold range (step S606: No), the comparison of the optical system's count value (step S517) is performed from the reference whiteboard scanning position C to the initial carriage position A. This allows for a similar flowchart to be used to determine whether the problem is with carriage 2 or the optical system during the reference whiteboard scanning operation, and recovery can be expected in the case of a sudden malfunction. In other words, the operation to determine if carriage 2 is malfunctioning and to perform a reciprocal scan of carriage 2 is also applied to the reciprocal scan operation of carriage 2 up to the reference whiteboard 10.

[0062] Figure 8 shows an example of the error log screen display according to this embodiment. In the flowcharts shown in Figures 6A, 6B, 7A, and 7B, even if an error pattern or an abnormality on the reference whiteboard 10 occurs once, if it can be recovered through retry processing, it will appear to the user that nothing happened. However, an error has actually occurred once, and by counting the number of errors in the internal memory, it can be used as a predictive tool for analyzing potential failure causes, even if it has actually been recovered through retry processing. As shown in Figure 2, the control board is equipped with non-volatile memory, so it is possible to keep it as an error log. In other words, the motor drive device 202a saves the history of when an abnormality is detected in the carriage 2 to the memory 207. This makes it possible to check the frequency of abnormality detections in the market and use it for failure prediction and analysis.

[0063] Figure 9 shows an example of the control panel screen according to this embodiment. If a sudden error occurs and a retry process is performed, the user will see the image reading device 101, such as a scanner, behaving differently than usual, resulting in a waiting time of several seconds. To alleviate the user's anxiety in this situation, the control panel screen may display an "automatic recovery in progress" screen while the machine is performing the retry process. If recovery is not possible through the retry process, an error message will be displayed; if recovery is successful, a message indicating this will be displayed, thereby alleviating the user's anxiety. In other words, the image reading device 101 may have a control panel screen that displays a screen pattern to notify the user when an abnormality in the carriage 2 is detected. This allows the user to be presented with appropriate corrective actions.

[0064] Figure 10 illustrates an example of the effects of this embodiment. Recent machines such as multifunction printers have an automatic reboot function that attempts to recover by automatically turning the machine's power off and on when an error occurs. Conventionally, with machines that do not have an automatic reboot function, when a problem occurs, the customer must directly contact the manufacturer's maintenance by phone, and a maintenance person must visit or give instructions over the phone to restart the machine by turning the power off and on to check whether it will recover. This series of operations is troublesome as it requires the customer to contact maintenance at least once, and it takes several tens of minutes.

[0065] For machines with automatic reboot functionality, when an error occurs, the machine automatically shuts off and then on again, saving the customer the trouble of contacting maintenance. However, since it takes several minutes for the machine to shut off and then on again, copying or scanning cannot be performed immediately after an error, causing stress to the customer. In this embodiment, the above problem can be solved by retry processing, and since the time required for retry processing is only a few seconds, it is possible to minimize the time to recovery even when an error occurs.

[0066] Figure 11 shows an example of an image forming apparatus equipped with an image reading device according to this embodiment. Up to this point, it has been described as an image reading device, but any function that uses the reading operation with the image reading device according to this embodiment can be applied not only to scanning operations, but also to copying and faxing functions as an image forming apparatus. The image forming apparatus shown in Figure 11 is a device that can use copying, scanning, and faxing.

[0067] The image forming apparatus 100 basically consists of a paper feeding unit 103, an image forming apparatus body 104, a scanner (image reading device) 101, and an automatic document feeder (ADF) 102. The image forming apparatus body 104 is an example of an image forming unit that forms an image read by the scanner 101 onto recording paper. Inside the image forming apparatus body 104 are a tandem-type image forming unit 105, a registration roller 108 that supplies recording paper to the image forming unit 105 from the paper feeding unit 103 via a transport path 107, an optical writing device 109, a fuser and transport unit 110, and a double-sided tray 111.

[0068] The image-forming unit 105 has four photoreceptor drums 112 arranged in parallel, corresponding to the four YMCK colors. Around each photoreceptor drum 112, image-forming elements including a charger, developer 106, transfer unit, cleaner, and static eliminator are arranged. An intermediate transfer belt 113 is positioned between the transfer unit and the photoreceptor drums 112, stretched between the drive roller and the driven roller, and held between the nips of both.

[0069] In the tandem-type image forming apparatus 100 configured in this way, light is written to the photosensitive drum 112 corresponding to each color (Y, M, C, K), and each toner is developed in the developer unit 106. These are then primary-transferred onto the intermediate transfer belt 113 in the order of, for example, Y, M, C, K. After the four superimposed full-color image from the primary transfer is secondary-transferred onto recording paper, the paper is fixed and ejected to form a full-color image on the recording paper. By equipping the image reading device according to this embodiment in the image forming apparatus 100, it is possible to provide an image forming apparatus that can reduce downtime compared to conventional machines.

[0070] Thus, according to the image reading device 101 of this embodiment, in the method for detecting abnormalities in the carriage 2 drive, even if an abnormality occurs when reading a document or a reference whiteboard 10, it is possible to distinguish whether the abnormality is in the optical system or the carriage 2 drive. Even if it is determined that the carriage 2 drive is abnormal, if the abnormality is recoverable, the device automatically determines whether recovery is possible without turning the power of the image reading device 101 off and on again, thereby reducing the downtime during which the user cannot use the image reading device 101.

[0071] Examples of the present invention are as follows: <1> An image sensor that reads an image of an object, A light source that irradiates the aforementioned object with light, A carriage comprising at least one of the image sensor and the light source, which reciprocates and scans in a one-dimensional direction, A position sensor for detecting the reference position of the carriage, A motor for driving the carriage, A motor drive device that generates a clock signal for the motor, A motor driver that outputs a motor drive signal to the motor to drive the motor according to the clock signal generated by the motor drive device, A pulse counter that counts the number of pulses of the clock signal generated by the motor drive device, Equipped with, If the motor drive device determines that there is an abnormality in the carriage based on the number of pulses counted by the pulse counter and the logic of the position sensor, it will perform a rescan operation, which is a scanning operation of the carriage, in the direction in which the logic of the position sensor changes. The image reading device performs the aforementioned rescan operation by again scanning the carriage back and forth over a distance equal to or greater than the distance traveled when the previous scanning operation of the carriage was performed normally. <2> The system includes a reference whiteboard for adjusting the reading density of the image by the image sensor, When reading the reference whiteboard, the motor drive device, based on the reading level of the reference whiteboard, determines that the reference whiteboard is at an abnormal level. If this is determined, it compares the number of pulses when the carriage is returned to the reference position with the ideal value. If the carriage is deemed abnormal, it performs a reciprocal scan of the carriage again to determine if the carriage is abnormal. <1> The image reading device described. <3> The motor drive device determines if there is an abnormality in the carriage during the document reading operation. If an abnormality is determined during the forward scanning of the carriage, it performs image reading when the carriage is scanned back and forth again. If an abnormality is determined during the return scanning of the carriage, it does not perform image reading when the carriage is scanned back and forth again. <1> or <2> The image reading device described. <4> The operation of detecting an abnormality in the carriage and performing a reciprocal scan of the carriage again is also applied to the reciprocal scan of the carriage to the reference whiteboard. <2> The image reading device described above. <5> The motor drive device stores in memory a history of when an abnormality is detected in the carriage. <1> from <4> An image reading device as described in any one of the following. <6> The control panel has a screen that displays a notification pattern to the user when an abnormality in the carriage is detected. <1> from <5> An image reading device as described in any one of the following. <7> It has at least one of the following functions: copy printing, scan transmission, and fax transmission. <1> from <6> An image reading device as described in any one of the following. <8> <1> from <7> An image forming apparatus comprising an image reading device as described in any one of the above, and an image forming unit that forms an image read by the image reading device on recording paper. [Explanation of symbols]

[0072] 2 carriages 3 light source 4 Image sensor board 5 Reflective mirror 6. Drive motor 7. Drive belt 8 Position Sensors 9. Document transport glass 10 Standard white board 11 Contact Glass 100 Image forming apparatus 101 Image reading device 102 ADF 201 Scanner Unit 202 Control board 202a Motor drive device 202b Motor Driver 202c Sensor detection unit 203 Pulse Counter 204 Interrupt Detector 205 Light source control unit 206 Image Processing Unit 207 memory [Prior art documents] [Patent Documents]

[0073] [Patent Document 1] Japanese Patent Publication No. 2007-279256

Claims

1. An image sensor that reads an image of an object, A light source that irradiates the aforementioned object with light, A carriage comprising at least one of the image sensor and the light source, which reciprocates and scans in a one-dimensional direction, A position sensor for detecting the reference position of the carriage, A motor for driving the carriage, A motor drive device that generates a clock signal for the motor, A motor driver that outputs a motor drive signal to the motor to drive the motor according to the clock signal generated by the motor drive device, A pulse counter that counts the number of pulses of the clock signal generated by the motor drive device, Equipped with, If the motor drive device determines that there is an abnormality in the carriage based on the number of pulses counted by the pulse counter and the logic of the position sensor, it will perform a rescan operation, which is a scanning operation of the carriage, in the direction in which the logic of the position sensor changes. The image reading device performs the aforementioned rescan operation by again scanning the carriage back and forth over a distance equal to or greater than the distance traveled when the previous scanning operation of the carriage was performed normally.

2. The system includes a reference whiteboard for adjusting the reading density of the image by the image sensor, The image reading device according to claim 1, wherein, when reading the reference whiteboard, if the reference whiteboard is determined to be at an abnormal level based on the reading level of the reference whiteboard, the motor drive device compares the number of pulses when the carriage is returned to the reference position with an ideal value, and if the carriage is determined to be abnormal, the carriage is scanned back and forth again to determine if the carriage is abnormal.

3. The image reading device according to claim 1 or 2, wherein the motor drive device determines if there is an abnormality in the carriage during document reading operation, and if an abnormality is determined during the forward scanning of the carriage, it performs image reading when the carriage is scanned back and forth again, and if an abnormality is determined during the return scanning of the carriage, it does not perform image reading when the carriage is scanned back and forth again.

4. The image reading device according to claim 2, wherein the operation of determining an abnormality in the carriage and performing a reciprocal scan of the carriage again is also applied to the operation of reciprocal scanning of the carriage to the reference whiteboard.

5. The image reading device according to claim 1 or 2, wherein the motor drive device stores in memory a history of when an abnormality is determined in the carriage abnormality detection.

6. The image reading device according to claim 1 or 2, further comprising an operation screen that displays a screen pattern for notifying the user when an abnormality in the carriage is detected.

7. The image reading device according to claim 1 or 2, comprising at least one of the functions of copy printing, scanner transmission, and fax transmission.

8. An image forming apparatus comprising: an image reading device according to claim 1 or 2; and an image forming unit for forming an image read by the image reading device on recording paper.

Images