The invention relates to image marking machines and more parti~
cularly, to the use OI diagnostics in image marking machines.
It is important to the maintenance of complex electronic equi~
5 ment such as reproduction machines to reduce the service calls and time spent in monitoring and maintaining the machine operation, in particular reducing the cost of maintenance and service. Part of the problem is the lack of similarity of diagnostic procedures and codes between various machines.
Often diagnostic procedures and trouble shooting codes ïor a particular 10 machine are totally unique to that machine, and the Service Representative must learn each machine's diagnostic procedures and codes separately. It would be desirable, therefore, to provide standardized diagnostic procedures and codes for use in many machines which the Service Represen~ative can use to correct malfunctions and maintain operation without the need for extensive 15 retraining.
Reproduction machines comprise several interrelated subsystems (often referred to as stations or chains) such as the paper path station, the exposure/scan station, the xerographic station, the document handler station and the fuser station. Checking the operation of the machine, it is often 20 necessary for the Service Representative to isolate on one of the stations orchains to the exclusion of the others. In doing so, the Service Representative is aided by status and maintenance codes displayed on a machine control panel to assist him or her in proper diagnosis and correction of machine malfunction.
ln prior art machines, however, there is generally no correlation or relation-25 ship between the codes and the particular chain being examined or diagnosed,nor was there any relationship in the sequence Oe codes that were displayed.
This necessitated the resort by the Service Representative to ex~ensive fault trees, charts and trouble shooting procedures to interpret the various codes into corrective procedures. It would be desirable, therefore, to eliminate the 30 need for resort to extensive trouble shooting procedures during machine diagnostics, and it would be desirable to provide a diagnostic system in which the displayed codes are related to various chains and are d;splayed in a predetermined sequence.
It is well known in prior art reproduction machines to display 35 various status and maintenance codes to assist the operator and service
representative in correcting malfunctions. In prior art maehines, diagnostic procedures were generally of a predictive nature. That is, the various status and maintenance codes that were displayed predicted the malfunction. The codes did not precisely monitor machine events. By machine events are meant 5 sequential exchanges of hardware related input or output information within a microprocessor controller subsystem. When a successful event has occurred, the chain or subsystem itself or a relate~ chain or su~system is allowed to advance to the next event. The status and mairltenance codes indicated corrective procedures. The Service Representative did not know the precise 10 condition of ~LI the various components in a particular chain c3r subsystem in the machine at the speciIic time that the ~ault occurred. This is ~ more direct rather than predictive method o~ trouble shooting. It would be desirable, therefore, to provide the Service Representative with fault code information and in addition, information on the precise status of each event or component 15 of the machine.
These prior art diagnostic procedures, as well as procedures for exercising various components in a reproduction machine including error and timing checks are disclosed in U.S. Patents 4,035,072 and 4,156,133, assigned tothe same assignee as the present invention. In addition, U. S. Patent
4, 305,653 teach~s sc~n carriage ~imin~ diagnostics.
Therefore, it is a primaIry object of the present invention to provide a new and improved diagnostic system for a reproduction machine, in 25 particular to provide a directive diagnostic system rather than a predictive diagnostic system. It is a further object of the present invention to be able totrack events in a sequential manner to provide the Service Representative with the l~st successful event completed, rather than to determine conditions in retrospect. It is another object of the present invention to correlate display 30 codes with events and chains in a variety of reproduction machines.
Briefly, the present invention is a control and diagnostic system that monitors all possible maehine events and activities that pass through microprocessor control. In case a fault is detected, the control will display the particular chain (subsystem~ of the machine and the last success~ully 35 completed event which occurred in that chain and on the copy which caused the shutdown. These chain (subsystem) and event numbers are common to the ,5 Y
5~3 components in a wide variety of machines and lmmediately provides a lower entry point in the usual fault isolation procedure. In another feature, subsystem sequencing, the Service Representative can select a chain number and then press start prin~. The machine will then display in sequence the numbers for the events in the selected chain as they occur and allow the Service Representative to selectively exercise the components. This feature can be provided for training purposes to aid in understanding sequence of subsystem operation. ~nother feature of the present invention is the use of dedicated regi.sters in the controller to record completed events for the various chains and components in the reproduction machine. At shutdown the contents of the registers can be displayed to indicate the last completed event for a particular chain(subsystem) or for each of the chains(subsystems).
In accordance with the present teachings, a method of diagnosing operation of a machine i5 provided wherein the machine has a plurality of subsystems, each oE the subsystems beIng divided into a plurality of processing events, the processing events being a sequence of operations relating to specific hardware components in the subsystem for controlling machine operation, a controller and a control panel for use in the machine diagnostics. The method which is provided comprises the steps of continuously monitoring each completed processing event in each subsystem, recognizing a machine malfunction in any of the subsystems, identifying the particular subsystem manifestlng the malfunction, responding to the machine malfunction, and indicating the completed processing events in the particular subsystem up to the point of malfunction in the subsystem in response to the machine malfunction.
In accordance with a further embodiment, a method of machine diagnostics is provided with respect to ~ printing machine which has an operator console and a plurality of components such as an optics component, a document handling component, a photoreceptor compolent and a copy sheet handling component, each of the components comprising a plurality of processing events to be completed in cooperation with the other components in the operation o~ the machine, each of the processing events being a sequence of the operation. The method which is provided includes the steps of monitoring the processing event of each machine component, counting the processing events in each component unon completiong storing an indication of each completed processing event in each component, and manifesting each completed processlng event whereby a record of :' 5~
-3a-completed processing events is maintained for machine diagnostics.
In accordance with yet a Eurther embodlment of the present teachings, a reproduction machine is provided which has a controller including an operator panel, a photoreceptor, and a plurality of operation components cooperating with one another and the photoreceptor to produce reproduc~ions, each of the processing components comprising a sequence of processing events to be completed in the operation of the machine, the controller coordinating the sequence of events to be completed in the operation of the machine and comprising a plurality of counters, each of the counters associated with at least one operating component, means to count the number of completed processing events in each operating component, means to record the last completed processlng event in a particular operationing component, means to detect machine malfunction, and means to display the last completed event in each of the components upon detection of a machine ~alfunction.
Other objects and advantages of the present invention will become apparent upon reading the following detailed description and upon reference to the drawings wherein the same reference numerals have been applied to like parts and wherein:
Figure 1 is an elevational view of a reproduction machine incorporating the present invention;
Figure 2 illustrates the control panel of the machlne shown in Figure l;
Figure 3 is a block diagram illustrating the controller of the reproduction machine of Figure l;
Figure 4 is a detailed schematic of the paper handling subsystem of the reproduction machine in accordance with the present invention;
Figure 5 illustrates a timing diagram, and Figures 6(.a), 6(b), 7(.a~ and 7(b~ are typical prior art fault isolation procedures for troubleshooting the paper subsystem and the scan drive s~bsystem.
Referring now to Figure 1, there i8 shown by way of example a reproducLion machine 10 including an image recording drum-like member 12, its outer pe~i-phery coated with a suitable photoconductive surface. The drum 12 moves the photoconductive surface in the direction of arrow 15 through a charging station 17 providing an electrostatic charge uniformly over the photoconductive surface.
3~iY3~3 - -3~-ThereaEter, the drum 12 is rotated to exposure station 18 and the charged photoconductive surface is exposed to a light image of the original document t.o be reproduced. 'rhe charge ls selectively dissipated in the llght exposed regions to record the origlnal document ln the form of an electro-i 7, ~
static latent image. After exposure ~rum 12 rotates the electrostatic latent image recorded on the photoconductive surface ~o development station 19 wherein a conventional developer mix is applied to the photoconductiYe surface of the drum 12 rendering the latent image visible.
Copy sheets 16 of the final support material are supported in a stack arrangement on either elevating stack main tray 20a or auxiliary tray 20b. With the stack at its elevated position, a sheet separator 21 feeds individual sheets therefrom to a registration system. The registration system includes r egistration switch 13 and registration rolls 14a and 14b. A copy sheel:
10 16 is registered in the nip of register rolls 14a and lD~b before transfer.
The sheet is then forwarded to the transfer station in proper registration with the image on the drum 12. The developed image on the photoconductive surface is brought into contact with a copy sheet 16 and the toner image is transferred from the photoconductive surface to the conta~ting 15 side of the copy sheet 16. Following transfer of the image the final support material is transported through a detack station where detack corotron 23 uniformly charges the support material to separate it from the drum 12.
The copy sheet 16 i5 then advanced to a suitable fusing station 24 for coalescing the transferred powder image to the support material. After 20 the fusing process, the copy sheet 16 is advanced to a suitable output device such as tray 25.
The original document to be reproduced is placed image side down upon a horizontal transparent pla~e 3û and scannecl by means of a moving optical system. The scanning system includes a stationary lens 21 and a pair of 25 cooperating movable scanning mirrors. The scanning mirrors include a half rate mirror 31 and full rate mirror 32 supported upon carriages (not illus-trated). Disposed along the platen 30 are a scan switch 33a and an end of scan switeh 33c.
A document handler is also provided including a registration assis-t 30 roll 35 activated when a document is inserted. Pinch rolls 38 are activated to feed the document around 180 de~ree curved guides 42~ The document is driven onto the platen 30 by a platen belt transport 3~. After copying, the platen transport 39 is activated and the document is driven off the platen by the output pinch roll 48 into the document cateh tray 49.
With reference to Figure 2, there is shown the machine control panel 23 including a keyboard with a two digit display 77, a start switch, a stop 5`~
switch, a copy lighter (CL) switch with indicator lamp, and a copy dark2r (CD) switch with indicator lamp. The control panel switches and inàicators are connected to the machine ccntrol as shown in ~igure 3.
With reference to Figure 3, there is shown a controller including microprocessor 50 with four dedicated registers, a scan register 51, a docu-ment handler register 52, and a pair of paper path registers 53 and 55. The reproduction machine also includes other, not shown, power supplies and distribution circuitry. A bidirec~ional bus 62 interconnects the microprocessor 50 an~ the reproduction machine and g~nerally conveys ~ignals from sensors 56 ~nd switches 54 of the reproduction machine to microprocessor 50 and conveys control signals from microprocessor 50 to the reproduction machineO
The signals of various reproduction maehine switches 54 and sensors 56 are conveyed through R resist~nce network 58 and suitable buffers 60 to the 8 bit external data bus 62 connected to microprocessor 50. The 8 bit lS d~ta bus 62 is also connected to a sui~able memory device such as EP~OM 64interconnected to microprocessor S0 through suiteble address lines ~8. It should be noted that the EP~OM device 64 can be replaced by a suitable read only memory ROM internal to the microprocessor 50.
Outputs to the reproduction rnachine controlled elements are conveyed from the microprocessor 50 Plong the external data bus 62 to various latches 68a, 68b and 68c. The latches are interconnected to various drivers 70, 71 and 72, or transistors 73 to activate various clutches, solenoids, motor drives, triacs and power supplies in the reproduction mAchine. For a more detailed description of the control, reference is made to u. s. Patent 4, 340, 807 .
In accordance with the present invention, for purposes of diagnos-tics, the reproduction machine is divided into separa~e stations or chains (subsystems) and individual components within each chain.
Chain Component Process Number Number Inputs Outputs Document 5 0 Prefeed Processing 5 1 5kuffer Motor 2 F eed 3 F orward Motor 8 Reverse Motor _. _ _ _ lQ Vptics 6 I Scan Clutch
6 2 Scan Switch Paper 8 1 Paper Feed Clutch Processing (selected tray) 8 2 Feed-in Switch 8 5 Feed-out Switch ~ or example, with reference to Table I, aboveg document pr~
cessing in the document handler is referred to as chain number 5 and includes an input prefeed switch, component number 0, an input feed switch, number 2~
20 an output skuffer motor, number 1 and output forward and reverse motors9 numbers 3 and 8.
The optics station is number 5 and includes scan clutch, component number 1 and scan switch, componen~ number 2. The copy sheet processing is chain 8 and includes the feed-in switch, component number 2, the fee~out 25 switch, number 5, and paper feed clutch, number 1.
To enter the diagnostic state, preferably, the following procedure is used. While activating the number tlO-- on the keyboard (see Figur e 2), a (not shown) power on switch is activated. If the system is in diagnosties, a predetermined number appears in display 77 on the reproduction machine 30 operator console or control panel. With the main power off, the system exits diagnostics. To access a diagnostic routine or procedureg it is necessary to enter the proper test code number (chain number and test number) using the panel keyboard on the operator console. To exit a particular routine~ enter another test number. To exit the chain, it is necessary to press a keyboard 35 switch (i.e. clear~ on the panel.
To test or exercise a particular component while in the diagnostic state, it is first necessary to enter the chain number and component or test number from the control panel. Once chain number is entered, any tests within that chain can be performed withou~ re-entering the chain number. For 5 component input tests, activating the input component selected will activate the component conlrol. The test wiU track the logic level at the printecl wiring board assembly (PWBA). That is, the indicators ti.e. copy lighter/darker LEDs are off) if the input is ground. The indicator LEDs are on if the input is high. For component output tests, entering the outpu~ component number 10 selected will activate the component control. Pressing a control switch (i.e.start print) will energize the particular component. Pressing a control switch (i.e. stop print) will de-energize the particular component.
To test process timing while in the diagnostic state, it is necessary to enter a chain number, then a given test number. The display will indicate 15 the time in real time (seconds/milleseconds). To start the test, "start print" is pressed. To stop the test, "stop print" is pressed. For example, Table II lists various tests in paper processing:
Test Time Chain No. Measurement -8 51 Paper Eieeder ON ~o Feed-in Switch Actuation 8 52 Scan Clutch ON to Feed-in Switch Deactuation 8 53 Feed-in Switch Deactuate to Feed-out Switch Actuation 8 54 Feed-out Switch Actuation to Feed-out Switch Deactuation With reference to Figure a" in accordance with the present invention, there is shown a transfer station in detail. As exemplary of the present invention, the sequence in the transfer of the image to a copy sheet (chain 8) can be broken down into six distinct events as identified in Table Ill~
The six events relate to activity of three components listed in Table I~
35 specifically, the actuation/deactuation or energized/de-energized status of these components.
-Sequence Event Number ~ =
Start Sequence 2 Paper F eed Clutch Energi~es 3 Feed-in Switch Actuation 4 Paper Feed Clu~ch De-energize Feed-in Switch Ve-actuates 6 F eed-out Switch Actuates 10 7 F eed-out 5witch Ve-actuates (Indicates Completion of Subsystem) In ac~ordance with the present invention, this is a breakdown of 15 the paper processing (ehain 8) into i~s most elemental steps or events which the microprocessor controls. Chain 8 is typical of the breakdown of all the chains or stations (subsystems) of the reproduction machine into elemental events for diagnostics.
In particular, there is the start o~ sequence, the paper feed clutch 20 energization to feed a copy sheet from trays 2na, 20b, and the lead edge of the copy sheet actuating the registration or feed in switch 13. Then7 the paper feed clu~ch is de-energized, a not shown scan controlled paper gate lifts and the trail edge of a sheet deactuates the switch 13. Finally~ the lead edge of the sheet actuates the exit or feed out switch 75, and the trail edge of the 25 sheet deactuates the swi-tch 75.
The indicators 8.1 ~ 8.7 arc displayed to indîcate completed events.
For example, an 8.2 shows that the paper feed clutch has been energized. It should be understood, however, that a display sequence 8.0 - 8.6 could be used.
With this type of display format, the display would indicate the nex$ event to 30 be completed rather than a completed event. In other words, an 8.2 display would indicate that a feed in switch actua~ion signal was not recorcled.
A typical timing diagram is illustrated in Figure 5. For example, at A the paper feed clutch is energized. The time period B is the time or the paper to reach the feed in swits~h 13. At C, the paper activates the feéd in 35 switch 13. The time period D is the time that the paper is under the feed in switeh. At point E, the paper leaves the feed in switch and the time period F
is the time that the paper is sensed at the feed out switch 75.
In accordance with the present inven tion, consider that the copy sheet does not reach tlle registration switch. Therefore, event 83 has not yet been completed and will result in a jam.
The jam will cause a "C4" code to be displayed. It is well known in the prior art to d;splay suitable codes representing jam conditions. In a typical prior art machine, the jam code "C4" would signify an out of paper condition or a paper misfeed. In accordance with the present invention, however, an additional chain and event number can be displayed after the jam code. The chain and event number, in this case 82, indicating the last successfully completed event, provides additional information to the Service Represen-tative and in many instances simplifies trouble-shooting.
The last successful event in the sequence would be an 82, or the energization of a paper feed clutch. The Service Representative will then be directed in the trouble-shooting procedure to test the registration switch, thatis the component control for the switch agrees Wit}l the maintenance code displayed, in this case "82". If appropriate, the cluteh would be checked. If the last event displayed was an 81, and there was also a C4 jam condition, the implic~tion would be that the paper feed clutch was not energized. That is, a signal was not sent to activate the clutch. Since this is not a likely result, the conclusion is that the microprocessor, in fact, did not provide the proper signal. This would indicate an erratic condition possibly caused- by an intermittent sensing component in another subsystem. The 80 maintenance eode associated with an E2 or E4 status code would also indicate a power problem which may have reset the microprocessor.
There is an order or hierarchy of problems that are handled. For first order type problems such as normal operating conditions and simple jams, only certain sequence numbers related to the components in a chain would occur. For example, 82, 84, 85, and 86 are directly related to jam conditions and prior art jam codes. If the diagnostlc package dealt only with the iirst order type problems, then these numbers could be eliminated using jam code numbers where a specific malfunction is related~ This is basically what is done in the prior art.
In accordance with the present invention, however, a hierarchy of problems can also be analyzed and monitored using ths~ chain and event numbers.
For example, consicler the condition of the feed-in switch 13 remaining closed after a copy sheet passes~ The display would provide a jam indication, for example, an E2 eode. The display would also provide an 84 indicating that the last completed event was the paper feeder clutch de-5 energiæed. ~faving this information avallable7 irl particular, the jam conditionas well as the last completed event5 it can be concluded ~hat there is a defective switch and/or a multifeed. Thus the code 84 provi~es more detail for problem resolution. In this case, the operator or Service Representative can quickly determine the multifeed status.
For another example, consider an intermittent feed-in switch or momentary deactuation with paper under the switch. The display would be an E3/83. The 83 indicates that the fee~in switch actuated a second time before the trail edge left the switch 13. With the use of the code 83, it is much easier to diagnose this type of intermittent fault. In particular~ in this case, it could 15 be caused by a false trail edge signal.
Other problems are extreme conditions causing the controller to operate out of sequence. For example, during operation, conditions can occur such as an open door, a power monitor trip, an auditron removal condition, or hitting stop print. These are often problems that are intermittent and 20 asynchronous in nature and can cause the processor to operate in an unpr~
dictable manner. The chain and event numbers can provide the pattern which is needed to isolate the contributing Factors.
With respect to Figures 6 and 7, there are illustrated typical prior art fault isolation procedures. For example, the Service Representative would 25 follow through the fault trees beginning with the first block. For example, (see Figure 7~ if a particular fault L9 was indicated, the Service Represen-tative would clear the paper path7 select one copy and press print. If the scan carriage started to move, then the Service Representative would check the paper feed clutch. If the scan carriage did not move, then the ~ervice 30 Representative would cheek to see if the proper voltage was available during standby. No matter what the particular fault, ~he Service Representative would proceed through the step by step procedure to isolate the problern. For example, if there was a noisy or intermittent scan switeh, the Service Represenl:ative would proceed through all the steps until reaching the point at 35 the end of the flow chart concerning possible intermittent or noisy switches.
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In accordance with the present invention, however, a much simpler procedure for trouble shooting is available. With reference to Table IV, there is shown a simplified procedure for an L9 fault code using the ehain and event codes in combination with the usual fault identification codes, Example:
With reference to Table V, the first column indicates the main-tenance code. The last successful controller event is the key to enter the chart. The chart provides the correcti~re action for the next event which failed to occur.
In particular, the procedure column gives a direct action to be performed in order of importance and the testing results. In most cases, it recommends the use of either an input or output component control test. For example, with an 8-2 maintenance code ancl a C4 status code, the procedure is to first check the paper trays, then test paper feed clutch output component i5 control, and then to operate the copier and observe the paper feed drive.
The normal indication column indicates the successful results of the recommended testing given in the procedure column. If a test is correct, then the Service Representative goes to the next recommended test or procedure. If the test is unsatisfactoryt then the Service Representative 20 would go to the recommended corrective action column.
The corrective action column gives the fault isolation method for any unsatisfactory test and is followed only when the test is unsatisfactory. Itprovides an exit from the chart to either service data or to more detailed trouble shooting methods covering a circuit or suspected component.
For example9 assuming 6 sequential events have to occur within the chain, if event 2 appeared in the display 77, i.e. 82, this would identify that chain 8 proceeded successfully only to event 2. The Service Representative would enter the chart or Table V troubleshooting proeedure at event 2. The chart indicates the activities that did not occur. This is the point where the 30 fault isolation begins.
In addition, the controller is monitoring all the other chains or su~
systems in the copier. If an additional fault occurs in another chain or subsystem, the controller will flash a new status code on display 77 indicating a new priority. It will be then necessary for the Service Representative to fix 35 the new problem before continuing with the original fault. For example, if troub]e shooting at the copy feed station and next7 a document handling problem is flashed, (Example: Al status cocle) the Service Representative would proceed next to the document handling trouble shooting charts.
An 80 chain or event code on the other hand~ indicates that the sequcnce did not start. In combination with an E4 fault code, the Service 5 Representative would be instructed to test the feed out switch if the status code oceured during power up. The normal indication in checking the test ~eed out switch is that the copy light/dark indicators are on when the feed out switch is deactuated. Appropriate corrective action would be to check for an actuatecl feed out switch or a short in the feed out switch circuit. If ~4/80 10 occured in the middle of a run, this would indicate a power problem and tirne trip circuitry which reset the controller.
In operation, as each event in the subsystem occurs, a real time event number will be monitored by the microprocessor 50 and available for display. In particular, the real time event number will be stored in scan 15 register 51, document handler registers 52~ or one of the paper path registers 53, 55, depending on which chain is appIopriate.
When a fault is detected, the readout on display ~ will provide the last successfully completed event or the first unsuccessful event processed by the controller prior to the fault. The event number will be the key to the 20 Serviee Representative in starting the trouble shooting. The diagnostic procedure incorporates the chain and event code with a jam status eode. The jam status codes are the typical jam status codes used in the prior art. When a jam shutdown occurs, the quantity select display will flash the jam status code associated with the rnalfunction. The last successfully completed event will 25 be available by pressing the "0" key on the control panel. Thus, the Service Representative with the use of the two codes can immediately focus on the malfunction or problem without having to go through a complex flow chart trouble shooting procedure.
Another featllre of the use of the chain and event codes is to 30 facilitate the testing of the various hardware components. For example~ the first hardware component to operate in chain 8 is the paper feed clutch. To exercise or test the paper feed clutch, the Service Representative would then enter code 81, 8 for chain 8 and 1 for the first component or event in the chain8 sequenee. Then the Service Representative would press start print to 35 energize the clutch and stop print to de-energize the clutch. The second event in chain 8 is the feed in switch. To exercise the feed in switch, the Service Represenative would enter the code 82. Activating the switch would track the logic level at the pr;nted wiring board, with the ground indicated by the copy lighter/darker LEDs off and high indicated by the copy lighl:er/darker LEDs on.
Another feature when in the hardware component exercising pr~
cedure is to be able to check critical intervals such as t;me intervals. For example, in chain 8, the time for the paper lead edge to actuate the feed-in switch 13 after print is critical. Entering a suitable code such as 8-51 will initiate a procedure to determin~ the time interval for the paper lead edge to 10 actuate the feed-in switch 13 aïter printO This interval will be provided in a real time readout form (in seeonds/milliseconds).
While tilere has been ;Llustrated and described what is at present considered to be a preferred embodiment of the present invention, it will be appreciated that numerous changes and modifications are likely to occur to 15 those skilled in the art3 and it is intended in the appended claims to cover all those changes and modifications wh;ch fall within the true spirit and scope of the present invention.