JP2006243348A - Fault location detecting method for image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce time and effort needed for repair in service work by separately specifying a malfunction in a communication line/a malfunction in a loaded drive signal generating section/a malfunction in load, in a composition in which the load of a printer main body is distributively driven by a drive unit connected to a D control substrate connected by serial communication. <P>SOLUTION: In a fault location detecting method, as shown in Fig. 2, a plurality of drive substrates 123 on which drivers for various drive components are mounted and a control substrate 301 composed of a CPU 302 and so on are separated. The drive substrates 123 and the control substrate 301 are connected by the serial communication. The drive substrates are provided with means for independently detecting an abnormal state in the communication line, an abnormal state within the substrates, and an abnormal state in each component that is driven. This makes it possible to exactly specify a fault location in fewer steps. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus that operates by driving a driving load such as a large number of motors and solenoids, and a failure detection method for the driving unit.

  In an image forming apparatus to which the present invention is applied, for example, in an electrophotographic image forming apparatus such as a copying machine or a page printer, a latent image is formed on a photoconductor by converting image information into an optical signal. In general, the image is visualized and a paper sheet is conveyed, and the formed image is transferred and formed on the paper. In these devices, multiple drive motors, solenoids, and clutches are used to move the image forming body and transport the paper. In addition, the image forming position is optimized by accurately transporting the paper and synchronizing with the image forming body. In order to achieve this, a plurality of position detection sensors are generally provided.

  Furthermore, in recent years, a microcomputer (CPU) capable of programming a series of operations is exclusively used as a sequence control means for executing the image forming operation.

  In addition, when the CPU controls the image forming operation as described above and determines that the operation cannot be continued normally for some reason, the CPU notifies the operator of the fact on the display unit or the like, thereby confirming whether the device has failed. It is programmed to be able to inspect whether and to safely terminate the device. The abnormal operation is recorded in a non-volatile memory or the like, and is used as a judgment material for parts replacement when a serviceman performs maintenance on the apparatus.

As a conventional example, for example, Patent Document 1 can be cited.
JP 2001-150773 A

  However, in recent years, since the required functions are increasing, the components constituting the apparatus are required to have severe performance and the total number of components tends to increase.

  In addition, the conventional method displays and records only the abnormal operation phenomenon. For example, even if “paper jam” remains, which part is abnormal or which component (motor, sensor) Since it was not possible to determine whether it was abnormal, etc., there was a waste of replacing even normal parts because there was a method of sequentially replacing possible parts. In addition, since a plurality of drive drivers composed of transistors for driving the motor and solenoid are mounted on the same control board as the CPU, the control board can be used even when one of the drivers fails. There was a drawback that additional waste was generated because everything had to be replaced.

  In order to solve the above-described problems, the present invention separates a plurality of drive boards loaded with drivers for each drive component from a control board composed of a CPU and the like, and connects the drive board and the control board by serial communication. At the same time, the drive board is provided with means capable of independently detecting abnormalities in the communication line, abnormalities in the board, and abnormalities in the driven parts, so that the failure location can be accurately identified with fewer procedures. .

  As described above, the configuration in which the signal at each stage of the drive unit can be verified via the reception signal line enables the failure location at the single component level to be identified with a simple configuration, and the replacement / repair of components. Work load can be reduced.

(First embodiment)
[Entire configuration of image forming apparatus main body]
First, the overall configuration of the image forming apparatus main body will be described with reference to FIG. In FIG. 1, an image forming apparatus main body A has a scanner unit B that is an image reading unit that reads image information of a book document at an upper portion thereof, and an image forming unit C that is an image forming unit at a lower portion thereof. The seat deck D is assembled to the lower part thereof.

  The scanner section B includes a scanning light source 201, a platen glass 202, a document pressure plate 203 that can be opened and closed with respect to the scanning body A, a mirror 204, a lens 205, a light receiving element (photoelectric conversion element) 206, an image processing section, and the like. Configured. Then, a book document such as a book, cardboard, or curl paper or a sheet-like document is placed on the platen glass 202 with the document surface facing downward, the back surface is pressed by the document pressure plate 203, set in a stationary state, and reading starts. When the key is pressed, the scanning optical source 201 scans the lower part of the platen glass 202 in the direction of arrow a to read image information on the original surface. Image information of the original read by the scanning light source 201 is processed by an image processing unit, converted into an electrical signal, and transmitted to the laser scanner 111.

  Here, the image forming apparatus main body A functions as a copying machine when a processing signal of the image processing unit is input to the laser scanner 111, and functions as a printer when an output signal of the computer is input. Further, if a signal from another facsimile apparatus is received or a signal from the image processing unit is transmitted to another facsimile apparatus, the apparatus functions as a facsimile apparatus.

  On the other hand, a sheet cassette 1 is mounted at the lower part of the image forming section C. The sheet cassette 1 is configured as one feeding unit with two cassettes, a lower cassette 1a and an upper cassette 1b. In this conventional example, two feeding units U1 and U2 are mounted, and four cassettes are mounted. One feeding unit U1 positioned above is detachably attached to the apparatus main body A, and the lower feeding unit U2 is detachably attached to the seat deck D.

  As will be described later, the sheets stored in the cassettes 1a and 1b are fed out by a pickup roller 3 serving as a feeding rotating body, and are separated and fed one by one by the cooperative action of the feed roller 4 and the retard roller 5. After that, it is transported by the transport rollers 104 and 105, guided to the registration roller 106, and fed to the image forming unit C by the roller 106 so as to be synchronized with the image forming operation.

  Separately from the sheet cassette 1, a manual feed tray 10 is disposed on the side surface of the apparatus main body A, and the sheet S on the tray 10 is fed out to the registration roller 106 by the manual feed roller 11.

  The image forming unit C includes an electrophotographic photosensitive drum 112, an image writing optical system 113, a developing device 114, a transfer charger 115, and the like. A laser beam corresponding to the image information emitted from the laser scanner 111 is scanned by the image writing optical system 113 on the surface of the photosensitive drum 112 uniformly charged by the charger to form a latent image. A toner image is formed on the image by the developing device 114, and the toner image is transferred onto the first surface of the sheet by the transfer charger 115 onto the sheet conveyed in synchronization with the rotation of the photosensitive drum 112 by the registration roller 106.

  Reference numeral 117 denotes a conveyance unit that conveys a sheet on which a toner image is formed, 118 denotes a fixing device, and 119 denotes a discharge roller. The sheet on which the toner image is formed is conveyed to the fixing device 118 by the conveying unit 117 and is heated and pressed to fix the toner image on the surface of the sheet. Then, the sheet is placed on the sorter 120 disposed outside the apparatus by the discharge roller 119. Discharged and loaded.

  When images are recorded on both sides of the sheet, the sheet discharged from the fixing device 118 is sandwiched between the discharge rollers 119, and when the rear end of the sheet passes through the branch point 207, the discharge roller is reversed and the sheet is reversed. After the sheet is once placed on the double-sided tray 121, the sheet is conveyed by the conveying rollers 104 and 105, reaches the registration roller 106, and the inverted sheet is formed with an image on the second surface in the same manner as described above. It is configured to be discharged and loaded on the sorter 120.

  As an example, the paper discharge roller 119 and the conveyance branching unit 207 are connected to a stepping motor 121 and a solenoid 122 for driving, respectively, and driven according to a drive current from the drive driver board 123.

  The substrate 123 is connected to a control unit (not shown) through a communication line, and is driven so that the motor 121 or the solenoid 122 operates appropriately according to the operation of the main body A.

  Accordingly, if there is an abnormality in at least one of the motor 121, the solenoid 122, or the driver board 123, the above-described sheet conveying operation is not performed normally, and an abnormal operation such as a paper jam or tearing occurs. However, even if an abnormal operation as described above occurs, it is highly possible that any (or all) of 121 to 123 is likely to have an abnormal location. Is difficult to do.

(Details of failure detection method)
FIG. 2 is a diagram for explaining the connection between the drive board 123 and the controller board as the control unit.

  Reference numeral 301 is a controller board, 302 is a CPU, 322 is a drive board control IC, and 302 and 322 are connected by an IF bus 325, and a condition for driving a driven part by the CPU 302 is set to 322 via 325.

  Reference numerals 303 to 305 denote communication lines for connecting the driving board and the controller board, 303 denotes a driven part, that is, a transmission line for transmitting data for driving the motor 121 and solenoid 122, and 304 denotes a receiving line for receiving data from the board 123. Data is exchanged as asynchronous serial data in synchronization with the trigger 305.

  A reception buffer 306 receives the data from 303 and branches to the output 313, and 307 drives the drive drivers 312A, B,... By converting the reception data via 306 from serial to parallel in synchronization with CLK321. , 308 is a first PS converter that converts 307 outputs 317 -A, B,... Again from parallel to serial and outputs them to output 314. The final outputs 318-A, B,... For driving the drive units 121 and 122 are output. 318 is a non-logic waveform generally based on the power supply Vdd. 309 converts the low voltage signals 319-A, B,..., 318 and Vdd converted by the voltage converter 320 formed of a Zener diode, etc., into serial again in synchronization with the CLK 321 and outputs it to the output 315. PS conversion unit. 310 is a third PS converter that outputs a plurality of detection means inputs (323, 324) such as SW and sensors to the serial signal 316 in synchronization with 321. 311 is transferred to 304 according to the switching signal 326 to 313-316. A signal selection unit that selectively outputs one of them is configured so that the control IC 322 can detect the signals of the sensors 323 and 324 as serial signals by connecting 316 to 304 during normal operation.

  The time chart when these circuits are operating normally is as shown in FIG.

  The drive control IC 322 outputs a start trigger 305-a in response to the communication start signal 305, and then transmits a serial signal corresponding to the parallel drive signals 317-A, B,. Here, it is assumed that signals of 1 → 0 → 1.

  First, the output 313 of the branch buffer unit 306 outputs a similar waveform almost simultaneously when 303 is received.

  Further, the serial-to-parallel conversion unit 307 determines and outputs the outputs to a plurality of signals 317-A, B... When the final data is received. 308 outputs a signal obtained by directly converting 317 into parallel-to-serial using 305-B as a start signal.

  309 converts the load drive signal 318 output from the driver 312 and Vdd to the logical signal level via the Zener diode 320 in accordance with 317, and converts 319 to 305-B as a start signal and outputs 315.

  FIG. 4 is a flowchart of a procedure for identifying a fault location, and FIGS. 5 to 7 are schematic diagrams of signals at the time of abnormality.

  Next, the operation of the present invention will be described with reference to these drawings.

First, when an abnormal operation such as a paper jam related to the motor 121 or the solenoid 122 occurs, the operator starts the failure specifying operation by a certain operation. (401)
As a first step, the selection output unit 311 connects the output 313 of the branch buffer 306 to the return line 304. After that, a waveform having a changing point where data 501 changes as 1 → 0 and 0 → 1 is output to 303. (402)
At this time, if there is a short circuit to GND in the communication lines 303 and 304 and the branch buffer 306, the reception 304 in the control IC is fixed to 0 level as in 502.

  Similarly, when shorting to HIGH level, 503 is obtained. Alternatively, an abnormality in which the waveform is disturbed as in 504 may occur.

At this time, the control IC compares the output waveform 501 with the output waveform, and determines that the communication unit is normal if they are the same. (403)
If different waveforms such as 502, 503, and 504 are recognized, it is notified that there is an abnormality in the communication unit, and the test mode is terminated. (404)
If it is determined that the communication unit is normal, 311 connects 314 to 304. Thereafter, the control IC outputs a test pattern to 303 as in (402). (405)
At this time, as described in FIG. 3, the control IC 322 outputs the result obtained by reconverting the waveform 317 obtained by serial-to-parallel conversion of the output 303 at 307 in the first parallel-to-serial conversion unit 308 as described with reference to FIG. Compares the reception results after one cycle to determine whether they are the same. (406)
Specifically, as shown in FIG. 6601, the data corresponding to each 317 terminal is transmitted twice so as to inspect both the case of 1 and the case of 0, and the result is inspected.

As shown in FIG. 6 602, if the same pattern is returned twice, it is determined to be normal, and if a mismatch is found in either the first time or the second time of data corresponding to 317-A as in 603, “ 317-A "Anomaly is notified and the test mode is terminated. (407)
If normal at 406, 311 connects 315 to 304 and outputs a test pattern to 303. (408)
In this case, since the parallel output 317 converted by 303 at 307 is the motor / solenoid drive signal 318 converted by the driver 312 and Vdd not transmitted serially as shown in FIG. The serial signal 315 obtained by converting the converted 319 by the second parallel / serial conversion unit 309 does not necessarily match 303.

Therefore, as shown in FIG. 7A, the control IC 322 creates a check pattern CP that is expected to be returned when everything corresponding to the test pattern 303 is normal, and compares it with the reply 304 from the drive substrate 123. (409)
At this time, if a pattern that matches all the CPs is returned via 304, the unit 123 passes all tests and ends the test mode as normal. (410)
However, as shown in FIG. 7B, for example, if a mismatch is detected in the data corresponding to 318 (319) -E, “318-E abnormality, driver 312B, solenoid 122 failure”
Then, identify the load and driver that may cause the failure and finish the test. (411)
The above test mode is executed to identify the faulty part, and the operator restores the apparatus by exchanging and repairing the corresponding part.

(Second embodiment)
FIG. 8 is an explanatory diagram as a second embodiment of the present invention. The same elements as in the previous figure are given the same numbers.

  Reference numerals 804 and 805 denote selectors that count the activation trigger 305 and connect one of a plurality of input signals to the output.

  Specifically, as shown in FIG. 9, the inputs 317-N and 319-N (N: natural number) are added to the outputs 802 and 803 every two cycles of 305, and N is switched and connected.

The parallel-to-serial converter 310 converts the output signals of 306, 804, 805 and the output signals of the sensors 323, 324... Into a serial signal in synchronization with the CLK 321, and outputs it to 304. (Fig. 10)
The failure location identification procedure is (TEST1)
1. Transmit 303 such that 801 becomes 1 in the first cycle. Transmit 303 such that 801 becomes 0 in the second cycle, and inspect the portion corresponding to 306 of the received signal 304 (TEST2).
1. Send 303 in which 802 (317-1) becomes 1 in the first cycle. Send 303 in which 802 (317-1) becomes 0 in the second cycle, and find the location corresponding to 804 in the received signal 304. Inspection
...
Is repeated N times (N: number of bits to be tested).

  This allows all bits of 317-N to be tested.

(TEST3)
1. Send 303 in which 803 (319-1) becomes 1 in cycle 1.1 Send 303 in which 803 (319-1) becomes 0 in 2.2 cycle, and find the location corresponding to 306 in received signal 304 Inspection
...
Is repeated N times (N: number of bits to be tested).

This allows all bits of 319-N to be tested.
In this order, the control IC identifies the failure location depending on whether or not the corresponding bit of the received signal 304 matches the expected value.

(Third embodiment)
In the first embodiment, a parallel-to-serial converter is used for returning a signal after parallel conversion, and in the second embodiment, a selector is used, but these may be mixed depending on the TEST location.

  Further, a Zener diode is used for the conversion from the load drive signal (318) to the detection signal (319), but it is needless to say that other means such as voltage division by a resistor may be used.

1 is a schematic sectional view of an image forming apparatus according to an embodiment of the present invention. Configuration block diagram of the first embodiment FIG. 1 is a signal transition diagram illustrating the first embodiment. Operation explanatory flowchart of the first embodiment FIG. 2 is a signal transition diagram for explaining the operation in the first embodiment. FIG. 3 is a signal transition diagram for explaining the operation in the first embodiment. Operation block diagram (A) and signal transition diagram (B) in the first embodiment Configuration block diagram of the second embodiment Flow chart explaining operation of signal switcher in the second embodiment Signal transition diagram for explaining the operation of the second embodiment

Explanation of symbols

119 Paper discharge roller 121 Stepping motor 122 Solenoid 123 Load drive unit 207 Conveyance branch member 301 Control board 303 Serial transmission signal 304 Serial reception signal 305 Serial timing signal 307 Serial parallel converter 308, 309, 310 Parallel serial converter 311 switching SW
320 Zener diode (voltage conversion)
804, 805 Signal selection connector

Claims (4)

  In an image forming apparatus that conveys a cotyledon-like member to a recording unit by controlling a plurality of driving loads such as a motor and a solenoid, and forms an image on the member, at least one driving means and an inside of the apparatus for driving the driving load A plurality of drive units having input means for receiving at least one signal of a plurality of detection means for detecting the state of the signal, a transmission signal line for transmitting the drive signals of the drive units and the drive means in time series, and a time series signal Connected to the reception signal line for receiving the image signal, and has a control means for controlling the drive unit in accordance with the operation mode of the image forming apparatus or the detection result of the detection means, and the drive unit outputs a transmission signal from the control means. A first conversion means for converting the output of the return means, the first conversion means for converting the transmission signal into a drive means drive signal, and the output of the first conversion means into a time-series signal again; Means, a second reconversion means for converting the output signal of the driving means into a time series signal, a detection signal conversion means for converting the signal of the detection means into a time series signal, the reply means, and the first and second reconversion means And a switching means for selectively outputting the output of the detection signal conversion means to the reception signal line, and the control means verifies the specific signal output to the transmission signal line and the reply from the reception signal line to thereby verify the failure location in the drive unit. Fault location detection method that identifies   2. The failure location detection method according to claim 1, wherein the detection means executes an inspection mode in which the switching means sequentially outputs the return means, the first and second reconversion means, and the detection signal conversion means to the reception signal line.   In an image forming apparatus that conveys a cotyledon-like member to a recording unit by controlling a plurality of driving loads such as a motor and a solenoid, and forms an image on the member, at least one driving means and an inside of the apparatus for driving the driving load A plurality of drive units having a function of receiving at least one signal of a plurality of detection means for detecting the state of the signal, a transmission signal line for transmitting the drive signals of the drive units and the drive means in time series, and a time series signal. Connected by a reception signal line for receiving, and has a control means for controlling the drive unit according to the operation mode of the image forming apparatus or the detection result of the detection means, and the drive unit returns a transmission signal from the control means And a first selection means for selectively outputting one of the outputs of the first conversion means and a first conversion means for converting the transmission signal into a plurality of drive means drive signals. Second selection means for selectively outputting one of a plurality of output signals of the drive means and second conversion for converting the signals of the return means, the first and second selection means, and the detection means into one time-series signal A failure location detection method in which a failure location in the drive unit is identified by verifying a specific signal output to the transmission signal line and a reply from the reception signal line.   4. The failure location detection method according to claim 3, wherein the selection switching in the first and second selection means is performed by a synchronization signal of the transmission signal.

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