JP2009028908A - Processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent decrease of a processing efficiency by avoiding processing stop by making a detecting means other than an abnormal detecting means a substitute even if a part of the detecting means is abnormal. <P>SOLUTION: A plurality of sensors 32 for detection of recording papers are arranged scattering on a conveyance route of the recording paper 30. A reach time between the adjacent sensors 32 is estimated. A conveyance state is monitored by comparing the estimation with an actual measurement. In this configuration, other sensors 32 are made substitutes even if any of the sensors 32 is abnormal, and the reach time to the substitute sensor is estimated. A monitoring task is thus made changeable to compare the estimated time with an actually measured value, and therefore unnecessary processing stop can be avoided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a processing apparatus that arranges a detection unit along a conveyance path along which a medium is conveyed, and executes a predetermined process on the medium based on a detection result of the medium by the detection unit.

  Sensors are installed at various locations on the transport diameter of the image forming apparatus. By detecting the leading edge of the paper, it is checked whether the transport is normal. The detection by the downstream sensor is awaited.

  This detection waiting time can be predicted to some extent depending on the sheet conveyance speed. If the sheet does not reach the estimated time, a conveyance error occurs.

  However, as an element that cannot detect the paper due to a sensor failure, there are cases where the function is completely stopped (failure), or paper dust adheres to the detection surface, and there are cases where the function can be restored with simple maintenance, Regardless of the reason for the function stop, the image forming process itself stops because of productivity.

Japanese Patent Application Laid-Open No. 2004-228620 proposes to accurately grasp a jam trouble occurrence state and enable accurate and efficient maintenance. In this patent document 1, it is disclosed to obtain a customer's approval for a sensor required for maintenance so that the sensor can be continued.
JP 2004-322650 A

  However, in the conventional technology such as Patent Document 1, since there is a period in which the image forming process is not stopped, it is not possible to maintain the processing efficiency equivalent to a normally functioning state.

  In consideration of the above facts, the present invention can prevent processing stoppage and prevent a decrease in processing efficiency by detecting a part other than the abnormality detecting means, even if part of the detecting means is abnormal. The object is to obtain a processing device that can be used.

  The present invention provides a plurality of detections provided along a transport path along which a medium is transported, mainly having a main detection function for detecting the presence or absence of the medium, and a sub-detection function for detecting the presence or absence of the medium as a substitute. Means, a conveyance control means for controlling the conveyance of the medium based on the detection result by the detection means, and a process execution means for executing a predetermined process on the medium based on the medium conveyance control by the conveyance control means When the execution of the main detection function in the detection means becomes impossible, a detection means different from the detection means incapable of executing the main detection function is designated as a substitute, and detection of this substitute And a proxy control means for causing the means to execute the main detection function and the sub-detection function in parallel.

According to the present invention, when the execution of the main detection function in the detection means becomes impossible, the detection means different from the detection means incapable of executing the main detection function is designated as a substitute. By causing the substitute detection means to execute the main detection function and the sub-detection function in parallel, it is possible to avoid the stop of the processing apparatus and maintain the processing efficiency.
Processing equipment.

  In the present invention, the predetermined process is a process related to a part of another process, and the predetermined process is performed in a state in which the state of conveyance of the medium is synchronized with the another process state. The process is executed, and a relative comparison value that is most important for the detection means for achieving this synchronization is given to each detection means.

  If the detection means for synchronizing is out of function, there may be a decrease in the accuracy of conveyance for synchronization.For example, the importance of the detection means such as changing the degree of warning with other detection means It is preferable to give superiority (relative comparison value). Hereinafter, the “relative comparison value” may be replaced with “importance” as necessary.

  Further, in the present invention, the another process is an image forming process in which an electrostatic latent image is formed on an image holding member and then developed by deflecting and scanning a light beam based on image data, and then developing the image. The predetermined process is an image transfer process to the medium which is a part of the image forming process.

  In the image forming process, the timing for transferring the image held on the image holding member to the medium conveyed along the conveyance path is important. That is, the predetermined process is an image transfer process to the medium, which is a part of the image forming process, and the transfer timing is obtained based on the detection by the detection means.

  By increasing the importance of the detection means for obtaining the transfer timing, the influence on the image quality can be minimized even if processing efficiency is prioritized.

  As described above, according to the present invention, even when a part of the detection unit is abnormal, the detection unit other than the abnormality detection unit can substitute for the processing stop and prevent the processing efficiency from being lowered. It has an excellent effect.

  FIG. 1 is a schematic configuration diagram mainly showing a sheet conveying unit 12 in an image processing apparatus 10 according to the present embodiment.

  In the image processing apparatus 10, an image forming unit 14 is disposed so as to be adjacent to the paper transport unit 12.

(Image forming unit 14)
The image forming unit 14 is provided with an endless loop-shaped transfer belt (image carrier) 16. The transfer belt 16 is wound around a plurality of rollers 18 and rotates in a substantially rectangular shape in the direction of arrow A in FIG. 1 (counterclockwise direction in FIG. 1) by a driving force of a driving motor (not shown). ing.

  On the upper side of the transfer belt 16 (upper side of the horizontal conveyance area), a charging device 20 is disposed on the upstream side in the conveyance direction of the transfer belt 16, and an optical scanning device 22 is disposed on the downstream side.

  In the charging device 20, the surface of the transfer belt 16 is uniformly charged.

  On the other hand, the optical scanning device 22 controls turning on / off of a laser as a light source based on input image data (hereinafter referred to as “lighting control”), and repeats the light beam whose lighting is controlled in one direction. Deflection to scan. This deflection direction is the main scanning direction, which is the depth direction in FIG. 1 (a direction perpendicular to the conveyance direction of the transfer belt 16).

  For this reason, the conveyance direction of the transfer belt 16 can be referred to as a sub-scanning direction with respect to the main scanning direction.

  That is, by rotating the transfer belt 16 uniformly charged by the charging device 20 at a predetermined conveyance speed, the main scanning light beam is output from the optical scanning device 22 (see arrow B in FIG. 1). An electrostatic image can be formed in a predetermined plane area on the transfer belt 16.

  A developing device 24 that develops toner by supplying toner as a developer to the electrostatic latent image is provided at the lower side of the transfer belt 16 (below the horizontal conveyance region).

  An image (toner image) developed and visualized by the developing device 24 is sent to the transfer unit 26 on the right side (on the right side of the vertical conveyance region) in accordance with the conveyance of the transfer belt 16. In the transfer unit 26, a toner image is transferred to a recording sheet 30 to be described later, and then the transfer belt 16 returns to the charging device 20 through a cleaning unit (not shown) (completion of one round).

  In the image forming unit 14, the image forming process is repeated by rotating the transfer belt 16.

(Paper transport unit 12)
As shown in FIG. 1, an upper and lower two-stage tray 28 </ b> A and a tray 28 </ b> B are provided at the center of the paper transport unit 12. Hereinafter, the tray 28A and the tray 28B are collectively referred to as “tray 28”.

  The tray 28 is accommodated, for example, in a state where recording sheets (mediums) 30 having different sizes are stacked.

  In addition, the tray 28 has a right side in FIG. 1 as a recording paper collecting side, and each has a tray sensor 32A-1 (for the tray 28A) for detecting the leading edge of the recording paper 30 immediately after being taken out. 32A-2 (for tray 28B) is provided.

  The recording paper 30 taken out from the tray 28 is guided by a plurality of rollers 34 and is turned approximately 90 ° in the clockwise forward direction of FIG. 1 to be conveyed downward in FIG.

  A downward conveyance sensor 32B is provided at a predetermined position when the downward conveyance is performed. The downward conveyance sensor 32B has a function of detecting the recording paper 30 conveyed from the tray 28 or a double-sided printing conveyance unit 36 described later.

  A plurality of rollers 38 are provided on the downstream side of the downward conveyance sensor 32B, and the recording paper 30 is guided by the plurality of rollers 38 and is turned in the forward direction of about 90 ° in the clockwise direction of FIG. It is conveyed almost horizontally.

  A transfer synchronization detection sensor 32C is provided on the downstream side of the horizontal conveyance region. The transfer synchronization detection sensor 32C has a function of synchronizing (timing) for normal transfer of the toner image to a predetermined area of the recording paper 30, and the recording paper 30 is transferred to the transfer synchronization detection sensor as necessary. It stops in a state where the tip is detected by 32C, and waits.

  A plurality of rollers 40 are provided on the downstream side of the transfer synchronization detection sensor 32C, and the recording paper 30 is guided by the plurality of rollers 40 and turned in the forward direction of about 90 ° in the clockwise direction in FIG. It will be transported upward.

  The transfer unit 26 described above is disposed in the middle of the upward conveyance path. In the transfer unit 26, the recording paper 30 is brought into close contact with the transfer belt 16 with a predetermined pressure, and toner is transferred from the transfer belt 16 to the recording paper 30 by electrostatic action. As a result, an image is transferred onto the recording paper 30. .

  A fixing unit 42 constituting a part of the image forming unit 14 is provided on the downstream side of the transfer unit 26 (upward in the upward conveyance direction). The recording sheet 30 onto which the image has been transferred in the transfer unit 26 is received, and is predetermined. The toner image is fixed on the surface of the recording paper 30 by applying heat and pressure.

  A pre-fixing detection sensor 32D is provided on the conveyance path between the fixing unit 40 and the transfer unit 26. The pre-fixing detection sensor 32D detects the leading edge of the recording paper 30 that is received by the fixing unit 40, and controls, for example, the temperature in the fixing unit 40 or the start timing of a mechanical operation for pressurization. I am doing so.

  A post-fixing detection sensor 32E is provided downstream of the fixing unit 40 in the recording paper conveyance direction. The post-fixing detection sensor 32E recognizes the end of the fixing process in the fixing unit 40.

  A plurality of rollers 44 are provided on the downstream side of the post-fixing detection sensor 32E, and the recording paper 30 is guided by the plurality of rollers 44 and is turned approximately 90 ° in the clockwise forward direction of FIG. It becomes a substantially horizontal conveyance.

  A print surface discrimination sensor 32F is provided on the transport path immediately after the substantially horizontal transport. This print surface discriminating sensor 32F has a role of detecting single-sided / double-sided print instruction information previously given to the recording paper 30. The detection result by the print surface discrimination sensor 32F is applied as a requirement for conveyance direction switching (point switching) at a branch portion of the conveyance path described later.

  The transport path for transporting the recording paper 30 in a substantially horizontal state by the transport roller 42 is provided with a first branch portion 46 on the downstream side of the print surface discrimination sensor 32F. The first branching unit 46 includes a plurality of transport rollers 48 and a switching point 50.

  Based on the information obtained by the print surface discriminating sensor 32F, the recording paper 30 currently being conveyed is (mode 1) a duplex printing instruction and printing on only one side has been completed (mode 2). ) It is classified as a case where a double-sided print instruction is given and double-sided printing is completed.

  In the case of (Mode 1), the recording paper 30 is turned approximately 90 ° by the conveyance roller 48 in the clockwise forward direction of FIG.

  In the case of (Mode 2), the recording paper 30 is maintained substantially horizontally conveyed by the conveying roller 48 by switching control of the point 50.

  The recording paper 30 whose direction has been changed by approximately 90 ° in the (mode 1) is sent to the duplex printing conveyance unit 36. The double-sided printing conveyance unit 36 is changed in direction by a plurality of conveyance rollers 49, and the conveyance timing is controlled based on the double-sided printing recording sheet detection sensor 32 </ b> G, and the conveyance path of the recording sheet 30 taken out from the tray 28. To join.

  A pass / fail judgment sensor 32H is provided in the transport path when substantially horizontal transport is maintained in the (mode 2). The pass / fail judgment sensor 32H reads the pass / fail judgment result related to the print processing.

  For example, when the amount of toner is not appropriate, when fixing is insufficient, when there is a problem in conveyance (diagonal conveyance, parallel movement, double feed, etc.), and when there is such a problem What is necessary is just to make it detect with the quality determination sensor 32H by marking. Alternatively, it may be a sensor unit having a control function for directly detecting and determining image density, paper position, and the like.

  A second branch portion 52 is provided in a substantially horizontal conveyance path on the downstream side of the quality determination sensor 32H. The second branch unit 52 includes a switching point 54.

  Based on the information obtained by the pass / fail judgment sensor 32H, the currently transported recording paper 30 is classified into (non-defective product judgment) and (defective product judgment).

  In the case of (non-defective product determination), the recording paper 30 is guided to the tray 56 on the upstream side in the conveyance direction (left side in FIG. 1) by switching control of the point 50. The number of recording sheets 30 discharged to the tray 56 is counted by a count sensor 32I.

  In the case of (defective product determination), the recording paper 30 is guided to the downstream side in the transport direction (the right side tray 58 in FIG. 1 by switching control of the point 50. The recording paper 30 discharged to the tray 58 is counted. The number of sheets is counted by the sensor 32J.

  A plurality of sensors 32 (A-1, A-2, B, C, D, E, F, G, H, I, J) are provided on the transport path of the paper transport unit 12 of the image processing apparatus 10 having the above configuration. However, if one of these fails and does not function, the image forming process itself has to be stopped (hereinafter referred to generically or when two or more sensors are indicated. 32 ”).

  That is, each sensor starts timing with the detection by the upstream sensor as a trigger, and even if it exceeds the allowable range of the arrival time predicted in advance from the conveyance speed and the conveyance distance (even if timed out) When 30 does not reach, there is a program for determining that a paper jam (jam) or the like has occurred. Since it was not possible to determine whether such a timeout was due to a sensor failure or whether a jam actually occurred, the image forming process is stopped.

  On the other hand, in this embodiment, when one of the sensors has a failure (including a temporary failure due to adhesion of paper dust or the like), a substitute for the failure is determined in advance and the functions are mutually compensated. We built a system that fits.

  FIG. 2 shows functional blocks of a transport system management control unit 60 that manages the transport state of the recording paper using the sensor 32 in the paper transport unit 12. In addition, each block which comprises the conveyance system management control part 60 does not limit the hardware structure of the conveyance system management control part 60, but is classified functionally.

  A UI (user interface) 62 mounted on the image forming apparatus 10 is connected to the conveyance simulation unit 64. In addition, a timer 66 is connected to the transport simulation unit 64.

  Here, when there is a print instruction from the UI 62, the conveyance simulation unit 64 takes out the recording paper 30 shown in FIG. 1 from the trays 28A and 28B, and even the conveyance along a predetermined conveyance path is the transfer process and the fixing process. The simulation is started with reference to the mounting position of each sensor 32 until the trays 56 and 58 are discharged.

  Since the conveyance speed of the recording paper 30 on the conveyance path is constant (with a temporary stop) and the conveyance distance between the sensors 32 is known, a conveyance simulation can be performed by simple four basic calculations (conveyance time). t = conveyance distance (distance) L / conveyance speed v).

  The simulation result in the conveyance simulation unit 64 is sent to the comparison unit 68.

  The comparison unit 68 is connected to the target sensor selection unit 70. Each sensor 32 (A-1, A-2, B, C, D, E, F, G, H, I, J) described above is connected to the target sensor selection unit 70, and from the designated sensor 32 The signal (detection / non-detection signal of the recording paper 30) can be sent to the comparison unit 68.

  The transport simulation unit 64 is connected to the target sensor selection unit 70. The transport simulation unit 64 sends print start time information to the target sensor selection unit 70 when a print instruction is issued from the UI 62.

  As a result, the target center selection unit 70 first selects the sensor 32 (A-1 or A-2) on the conveyance path through which the recording paper passes, and the signal is sent to the comparison unit 68 ( At the start of printing).

  Further, at the start of printing, the conveyance simulation unit 64 is connected to the timeout time instruction unit 72. The timeout time instruction unit 72 is also connected to the target sensor selection unit 70.

  The time-out time instruction unit 72 instructs the time measurement unit 74 to start measurement when the print start time information is received from the conveyance simulation unit 64 or when the target sensor information is received from the target sensor selection unit 70. . If this instruction is not given, it can be determined that there is an abnormality in the upstream sensor.

  That is, at the start of printing, the estimated time from when the print instruction is given until the recording paper 30 is taken out of the tray 28 to reach the transport path sensor 32A-1 or 32A-2 is measured. Moreover, after that, the estimated time between each sensor (for example, sensor 32A-1 to sensor 32B, sensor 32B to sensor 32C, etc.) is measured.

  When the time measuring unit 74 reaches the time-out time, a time-out signal is sent to the comparing unit 68.

  At this time, in the comparison unit 68, recording from the next sensor on the recording paper conveyance path (for example, the sensor 32B follows sensor 32A-1, 32A-2, and the sensor 32C follows sensor 32B). Waiting for a paper detection signal, a comparison is made as to whether or not the recording paper detection signal is input within a predetermined allowable range based on the timeout signal, and the result is sent to the pass / fail judgment unit 76.

  In the pass / fail judgment unit 76, if the result of the judgment as to whether or not the input is within the predetermined allowable range is OK, an OK signal is sent to the target sensor selection unit 70 and the timeout time instruction unit 72. Note that an NG signal is also sent to the timeout time instruction unit 72 (described later).

  With this OK signal, the target sensor selection unit 70 sets the next sensor as a detection target, and the timeout time instruction unit 72 sets the transport time to the next sensor as the timeout time.

  If the pass / fail determination unit 76 is NG, an NG signal is sent to the sensor substitute availability determination unit 78 and the timeout time instruction unit 72.

  The sensor substitute determination unit 78 identifies a sensor that has become NG, and determines whether another sensor can be used as a substitute. For example, when the sensors 32 (A-1), (B), and (C) are arranged in the order of (A-1) → (B) → (C) along the transport path, , (A-1) → (B) and (B) → (C) are monitored, but if the sensor 32B fails, the sensor 32C is used instead of the sensor 32B, and (32A-1) → ( 32C) refers to monitoring the state of conveyance between the two.

  Here, the transfer synchronization detection sensor 32 </ b> C is applied to a severe process of accuracy called transfer, and is set in advance as a highly important sensor.

  This importance setting is specified by the user by setting the importance in advance when, for example, letting the user set in advance whether or not to apply another sensor as a substitute. A sensor that includes a sensor that is more important than this sensor may not be substituted. On the other hand, a sensor having a lower importance than this sensor other than the designated sensor can be substituted. In the present embodiment, all sensors can be substituted by other sensors.

  The sensor substitute availability determination unit 78 is connected to the substitute designation unit 80, the image processing stop instruction unit 82, and the UI 62.

  A “possible” signal is sent to the substitute designation unit 80 when the sensor substitution is possible. As a result, the substitute designation unit 80 designates a substitute sensor based on the substitute sensor correlation data (see Table 1) stored in the substitute sensor correlation data memory 84 and sends it to the target sensor selection unit 70.

  Further, a “No” signal is sent to the image processing stop instruction unit 82 and the UI 62 when the sensor substitution is not possible. As a result, the image processing stop instruction unit 82 sends a processing stop signal to each control unit of the image forming unit 14 and the paper transport unit 12 and notifies (warns) that a sensor abnormality has occurred in the UI 62.

  On the other hand, when an NG signal is input to the timeout time instruction unit 72, the monitoring task is changed so as to indicate the timeout time until the sensor (information acquisition from the target sensor selection unit 70) determined as a substitute.

  For example, as shown in FIG. 3, normally, the recording paper 30 is detected by the sensor 32B after being detected by the sensor 32A-1, but if the sensor 32B is abnormal (failure), the sensor 32C is substituted. It becomes. As a result, the timeout time depends on the transport distance from the sensor 32A-1 to the sensor 32C.

  The operation of the present embodiment will be described with reference to the flowchart of FIG.

  In step 100, it is determined whether or not there has been a print instruction. If the determination is negative, this routine ends.

  If an affirmative determination is made in step 100, the process proceeds to step 102. In step 102, an initial sensor is selected. That is, the selected sensor (32A-1 or 32A-2) differs depending on the designated tray 28A or 28B.

  In the next step 104, a time-out period is indicated. For example, at the initial stage, the transport time t is calculated based on the transport distance (distance) L from the sensor 32A-1 (or 32A-2) to the sensor 32B and the transport speed v, and the timeout time is set based on the transport time t. To do.

  In the next step 106, measurement is started by the instructed timeout time, and the process proceeds to step 108.

  In step 108, it is determined whether or not the recording paper 30 (the leading edge) has been detected based on the signal from the selected sensor 32. If an affirmative determination is made, the process proceeds to step 110 and the measurement is terminated. Then, it is determined whether or not the arrival time of the recording paper 30 to the selected sensor 32 is within an allowable range (setting based on the transport time t), that is, whether the recording paper 30 is acceptable or not is determined.

  If the result of step 112 is OK, the process proceeds to step 114, where it is determined whether there is a next sensor (whether the conveyance of the recording paper 30 is continued). The next sensor 32 is selected at 116 and the process returns to step 104.

  If the determination in step 114 is negative, this routine ends.

  When it is determined as NG in step 112, the process proceeds to step 118. In step 118, it is determined whether or not substitutes are possible. In the present embodiment, since all the sensors 32 can be substituted by other sensors, basically, only “OK” determination is made. However, for example, two or more sensors 32 cause an abnormality. If yes, it may be determined as “No”.

  If “Yes” is determined in step 118, the process proceeds to step 120, the substitute sensor 32 is designated (selected), the process returns to step 104, and the above process is repeated.

  If “NO” is determined in step 118, the process proceeds to step 122 to execute error processing.

  As the error processing, an instruction to stop image processing is issued, a display indicating that the sensor is abnormal is displayed on the display surface of the UI 62, and an alarm is given through hearing.

  As described above, in the present embodiment, a plurality of recording paper detection sensors 32 are distributed on the conveyance path of the recording paper 30, and arrival times between adjacent sensors 32 are predicted, and prediction and actual measurement are performed. In the configuration in which the conveyance state is monitored by comparison with the other, even if any of the sensors 32 is abnormal, another sensor 32 is used as a substitute, and the arrival time to the substitute sensor is predicted and compared with the actual measurement value. Since the monitoring task can be changed as described above, unnecessary processing stop can be avoided.

  In the present embodiment, when the sensor 32 is abnormal, the substitute sensor 32 is automatically designated so that the operation of the processing apparatus is not stopped. However, when the sensor is abnormal, the process is temporarily stopped. Depending on the user's judgment, the user may select whether to request maintenance while continuing operation or to request maintenance in a stopped state.

  Further, in the present embodiment, it is possible to establish a substitute sensor for the abnormality of all the sensors 32 regardless of the relative importance set for the sensor 32. It may be possible to set whether or not. Moreover, it may be possible to set whether or not to substitute independently regardless of the importance.

Listed below are examples of substitute execution when a specific sensor fails based on Table 1.
(1) Failure of sensor 32A-1 or 32A-2 A sensor 32B (Vertical Transport Sensor) takes the place. If the start instruction information is not received, the sensor 32B determines that the sensor 32A-1 or 32-B has failed and acts as a substitute.
(2) Failure of sensor 32B A sensor 32C (Registration Sensor) takes the place.
(3) Failure of sensor 32C For example, when the conveyance speed is fast, the recording paper is delayed, and when it is slow, it becomes a trigger for increasing the conveyance speed. In the case of the sensor 32B, since the distance to the transfer is long, the problem is that the adjustment cannot be performed with high accuracy. However, the condition is that until the maintenance of the sensor 32C is performed.
(4) Failure of sensor 32D When this sensor 32D fails, the sensor 32C acts as a substitute. However, the period until the maintenance of the sensor 32D is performed is a substitute execution condition. This is because the life of the fixing unit is shortened if it is continuously used as it is.
(5) Failure of sensor 32E When this sensor 32E fails, the sensor 32F acts as a substitute. However, the period until the maintenance of the sensor 32E is performed is a substitute execution condition.
(6) Failure of sensor 32F When this sensor 32F fails, the sensor 32E acts as a substitute. However, the period until the maintenance of the sensor 32F is performed is a substitute execution condition.
(7) Failure of sensor 32G When this sensor 32G fails, the sensor 32F acts as a substitute. However, the period until the maintenance of the sensor 32G is performed is a substitute execution condition. This is because, if the printer is continuously used as it is, the double-sided print timing may not be obtained with high accuracy.
(8) Failure of sensor 32H When this sensor 32H fails, sensor 32F acts as a substitute. However, the period until the maintenance of the sensor 32H is performed is a substitute execution condition. This is because if it continues to be used as it is, it may not be possible to accurately obtain the discharge destination switching operation timing.
(9) Failure of sensor 32I When this sensor 32I fails, the sensor 32H acts as a substitute. However, the period until the maintenance of the sensor 32I is set as a substitute execution condition. This is because the normal discharge recording paper 30 may not be accurately counted if it is continuously used as it is.
(10) Failure of sensor 32J When this sensor 32J fails, the sensor 32H acts as a substitute. However, the period until the maintenance of the sensor 32I is set as a substitute execution condition. This is because the abnormally discharged recording paper 30 may not be accurately counted if it is continuously used as it is.

1 is a schematic configuration diagram of an image forming apparatus according to the present embodiment. FIG. 6 is a functional block diagram of a transport system management control unit that manages a transport state of recording paper in a paper transport unit. It is a transition diagram of the change of the monitoring task when the sensor is normal or abnormal. 6 is a flowchart showing a recording paper transport monitoring control routine using a sensor according to the present embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image processing apparatus 12 Paper conveyance part 14 Image formation part (process execution means)
16 Transfer belt (image carrier)
18 Roller 20 Charging Device 22 Optical Scanning Device 24 Development Device 26 Transfer Section 28 Tray 28A Tray 28B Tray 30 Recording Paper (Media)
32 sensor (detection means)
32A-1 Tray sensor (detection means)
32A-2 Tray sensor (detection means)
32B Downward conveyance sensor (detection means)
32C transfer synchronization detection sensor (detection means)
32D Pre-fixing detection sensor (detection means)
32E Detection sensor after fixing (detection means)
32F Print surface discrimination sensor (detection means)
32G Double-sided print recording paper detection sensor (detection means)
32H pass / fail judgment sensor (detection means)
32I count sensor (detection means)
32J count sensor (detection means)
34 Roller 36 Carrying part for double-sided printing 38 Roller 40 Roller 42 Fixing part 44 Roller 46 First branching part 48 Carrying roller 50 Switching point 49 Carrying roller 52 Second branching part 54 Switching point 56 Tray 58 Tray 60 Carrying system management control (Transport control means)
62 UI
64 Transport simulation unit 66 Timer 68 Comparison unit 70 Target sensor selection unit (substitute control means)
72 Time-out Time Instructing Unit 74 Time Measuring Unit 76 Pass / Fail Judgment Unit 78 Sensor Substitute Availability Judgment Unit 80 Proxy Designation Unit (Substitute Control Unit)
82 Image processing stop instruction section (substitute control means)
84 Proxy sensor correlation data memory (proxy control means)

Claims (3)

A plurality of detection means provided along a transport path along which the medium is transported, having a main detection function for mainly detecting the presence or absence of the medium, and a sub-detection function for detecting the presence or absence of the medium as a substitute;
Transport control means for controlling transport of a medium based on a detection result by the detection means;
A process executing means for executing a predetermined process on the medium based on the transport control of the medium by the transport control means;
When the execution of the main detection function in the detection means becomes impossible, a detection means different from the detection means in which the execution of the main detection function is disabled is designated as a substitute, and the substitute detection means Proxy control means for executing the main detection function and the sub detection function in parallel;
A processing apparatus.   The predetermined process is a process related to a part of another process, and the predetermined process is executed in a state in which the conveyance status of the medium is synchronized with the other process status. 2. The processing apparatus according to claim 1, wherein a relative comparison value in which the detection means for achieving this synchronization is most important is assigned to each detection means.   The another process is an image forming process for forming an image by forming an electrostatic latent image on an image holding body by deflecting and scanning a light beam based on image data, and developing the electrostatic latent image. 3. The processing apparatus according to claim 2, wherein the processing is image transfer processing to the medium, which is a part of the image forming processing.

Images