JPS63279177A - Checking device for photosensor - Google Patents

Abstract

PURPOSE:To facilitate the checking of a photo sensor, by reducing current flowing through a light emitting element below that in the normal operation to detect whether the drop in the level of the light receiving element is lower than a fixed level or not. CONSTITUTION:When a sensor checking signal S1 is H, normal light emitting operation is performed in such a manner that current flowing through light emitting elements of sensors 33-37 is only limited with respective resistances R1, R3 and R5. For checking, when the sensor checking signal S1 is turned to an L level, current flowing through the light emitting elements is limited with respective combined resistances R1+R7, R3+R8 and R5+R9. Under such a condition, the output level of output signals S2-S6 of light receiving elements is checked whether to exceeds a fixed value or not. When it is below the fixed level, a photo sensor is determined to be polluted to drive an alarm circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an optical sensor checking device having a light emitting element and a light receiving element, and is used as, for example, a sensor checking device of a copying machine.

[Conventional technology and its problems]

Copying machines use many optical sensors to detect the presence or absence of copying paper and the status of each part. In copying machines, paper dust is generated because a large amount of paper is handled, and toner powder often scatters and adheres to the optical sensor. In an optical sensor, light is blocked or reflected by a detection target existing in the optical path from a light emitting element to a light receiving element, and the presence or absence of the detection target is thereby detected. If the sensor becomes dirty with dirt or dust, the amount of light transmitted decreases, making operation unstable and causing detection failure or false detection.

However, in conventional copying machines, abnormalities are detected only when the optical sensor becomes extremely dirty and cannot be detected. It was not designed to prevent this. For this reason, for example, copying machine service personnel would clean the optical sensor to remove dirt during periodic inspections, but this was not reliable since optical sensors are usually installed in small spaces that are difficult to clean.

As a result, abnormalities may be detected due to dirt on the optical sensor.
Copying machines often stop working, take a long time to recover, and become unusable during this time.

[Technical means for solving the problem] In view of the above-mentioned problem, the present invention aims to check the state of dirt before the optical sensor used in copying machines becomes undetectable. The technical means for this purpose is a checking device for an optical sensor including a light emitting element and a light receiving element, comprising: current control means for reducing the current flowing through the light emitting element during checking compared to during normal operation; It is characterized by comprising a level detection means for detecting whether the output level of the light receiving element is above a certain level at the time of the check, and an alarm means for issuing an alarm when the output level of the light receiving element is not above the certain level. do.

[For production]

By reducing the current flowing through the light emitting element by the current control means compared to that during normal operation, the amount of light emitted by the light emitting element is reduced, and therefore the output level of the light receiving element is reduced. The level detection means detects whether the output level at this time falls below a certain level, and if the output level falls below the certain level, the alarm means issues an alarm.

〔Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front sectional view showing the general structure of a copying machine A. FIG. In the figure, a photoreceptor drum l that can be rotated counterclockwise is arranged approximately in the center of the copying machine body, and around it are an eraser lamp 2, an inter-image eraser lamp 4, a charger 5, and a developing device. A device 6, a transfer charger 7, and a blade type cleaning device 9 are provided. The photoreceptor drum 1 has a photoreceptor layer provided on its surface, and is uniformly charged by passing through an eraser lamp 2 and a charger 5, and then subjected to image exposure from an optical system 10.

The optical system 10 is installed below the original glass 16 so as to be able to scan the original image, and includes a light source 11a, a movable mirror 11.
12, 13, a lens 14, and a mirror 15. The light 1alla and the movable mirror 11 are driven by a scan motor M3 so as to move at a speed that is a constant ratio to the circumferential speed of the photoreceptor drum 1.

On the other hand, there are paper feed rollers 21 on the left side of the copying machine body.
．． An overprint paper section 20 and an underprint paper section 22 are installed, and the copy paper conveyance path is composed of rollers 24 and 25, a timing roller 26, a conveyance belt 27, a fixing device 28, and a pair of discharge rollers 29. There is. Note that 31 is a manual paper feed unit, 32 is an output tray, and 33 is a timing roller 2.
This sensor detects the presence or absence of paper (transfer paper) at position 6.

Also, in the scan path of the optical system 10, there is a registration sensor 33 for accurately imprinting an image on paper, a fixed position sensor 34 for detecting the standby position of the optical system 10 before starting scanning, and a position sensor 34 for detecting the waiting position of the optical system 10 before starting scanning. A maximum scan sensor 35 is provided for detecting the position and preventing collision of the optical system 10, and the overprint paper section 2
0 and the sketch paper section 22 are provided with paper detection sensors 36 and 37, respectively, for detecting the presence or absence of paper. These sensors 33 to 37 each include a light sensor having a light emitting element and a light receiving element.

FIG. 2 shows the arrangement of the operation keys and the display on the operation panel of the copying machine A. The operation panel 70 includes a print start key 71.7 for starting the copying operation.
A display device 72 consisting of segment LEDs and displaying the number of copies and a warning to be described later, 1, 2, . ...9
．． A numeric keypad 80 corresponding to the value 0, a clear/stop key 91, a density setting knob 93 for continuously changing and specifying the density of the copied image, and a paper empty display that indicates when the paper in the paper feed section is empty. 94,) A toner empty display section 95, a toner full display section 96, a jam trouble display section 97, and a sensor cleaning display section 98 that warns that the sensor is dirty and requires cleaning are arranged.

FIG. 3 shows a control circuit for each of the aforementioned sensors 33-37. In the figure, switching elements Ql, Q2 . Q3 is a knot element with open collector output, and when each input is “L”, the output is ° “■1” and the input is “H”
When , the output becomes "L".

In other words, when the sensor check signal sl is "H" (off), both ends of resistors R7, R8 and R9 are short-circuited, and when the sensor check signal S1 is "°L" (when on), Each resistor R7°R8, R9 is connected in series with a resistor R1, R3, R5, respectively.

Therefore, when the sensor check signal S1 is "H", the current flowing through the light emitting elements of each sensor 33 to 37 is limited only by the resistors R1, R3, and R5, and normal light emitting operation is performed. However, when the sensor check signal S1 becomes "off", the current flowing to the light emitting element is connected to the combined resistances R1+R7 and R3+R8, respectively.
, R5+R9, which reduces the current. The sensor check signal S1 is "H" in the normal copying operation state, and the sensor check signal S1 is "H" in the normal copying operation state.
When checking for dirt in sensors 3 to 37, the current goes to "L" and reduces about 20% of the current flowing to sensors 33 to 37, and in this state, the output level of the output signals 32 to S6 of the light receiving elements is equal to or higher than a certain level. It detects whether or not it is. Although the circuit for level detection is omitted here, it is also used as the detection circuit during normal operation. In other words, the output signals 52 to S6 are each determined to be "H" or "L" by a comparator, but the output signals S2 to S6 in the "H" state during normal operation of the copying machine are lower than the threshold level of the comparator. Since the level is sufficiently high, even when the output signals 32 to S6 are lowered by the sensor check signal Sl, detection is made based on whether or not they are still held at the "H" level.

Next, the processing procedures of the copying operation of the copying machine and the checking operation of the sensors 33 to 37 will be explained according to the flowcharts of FIGS. 4 to 9.

Figure 4 schematically shows the copying operation of the copying machine. When the power is turned on and the program starts, first, in step #1, the initial state of the CPU is set, and the number of copies per copy is initialized to 1. In step #2, an internal timer is set to define the length of the l routine. After that, input processing, output processing, and a series of other processes are performed from step #3 onwards, including the one-digit display routine in step #5, the tens-digit display routine in step #9, and the trouble display routine in step #13. , and the sensor check routine of step #14,
will be explained in detail next.

FIG. 5 shows a sensor check routine. First, in step #21, it is determined whether or not the copying machine is on standby. If it is not on standby, that is, when copying is in progress, the sensor is checked in step #26. Turn off the signal Sl (in other words, set it to H") and clear the sensor check timer in step #27. If it is on standby, it is determined whether or not there is a trouble in step #22, and if it is not in trouble, the sensor check timer is cleared. Step #23 determines whether the sensor check timer is cleared or not.This sensor check timer is used to cover the delay in the rise time of sensors 33 to 37 and obtain the sensor check timing. It is about several hundred μs.

If YES in step #23, the sensor check signal S1 is turned on (ie, set to L') in step #24, and the sensor check timer is set in step #25. Also, since the sensor check timer has already been set, if no in step #23, the sensor check timer is already set.
7 Determine whether the timer has ended in step #28,
If the process has not ended, a count process is performed in which the timer is decremented in step #32.

If yes to step #28, step #29
At step #30, each sensor 33-37 is checked by the output signal 52-S6, and at step #30, the output signal 32-S
If all of 6 are above a certain level (if normal)
Proceeding to step #26, if any of the output signals S2 to S6 is below a certain level (if there is an abnormality), a flag is set to display sensor dirt in step #31, and the type of the sensor is set. set.

FIG. 6 shows a trouble display routine. First, check the state of the toner empty flag in step #33, and if the toner empty flag is set, turn on the LED of the toner empty display section 95 in step #35, and if it is cleared, turn it off in step #34. Make it. Check the state of the toner full flag in step #36, and if the toner full flag is set, step #36
At step #38, the LED of the toner full display section 96 is turned on, and if it has been cleared, it is also turned off at step #37. Hereinafter, the same processing as described above is performed for the vapor empty display section 94 and the jam trouble display section 97 in steps #39 to #44.

Then, in step #45, the state of the sensor dirt display flag is checked, and if the sensor dirt display flag is set, the LED of the sensor cleaning display section 98 is turned on, and if it is cleared, it is turned off in step #46. do.

FIG. 7 shows a display routine for the tens digit of the LED display section consisting of seven segments of the display section π72. First step #
Check the jam trouble flag at step 48, and if the jam trouble flag is set, a jam trouble code is displayed at step #51, and if it is cleared, step #4
Check the sensor dirt display flag at step 9. If the sensor dirt display flag is set, the sensor dirt display code is displayed in the tens digit in step #52. The jam trouble code and sensor dirt display code are selected from among the seven segments of the LED. For example, the former is "J" or "
The latter displays "C", and the latter displays "d". If the flag is cleared in step #49, step #50
Displays the tenth digit of the number of copies as usual.

FIG. 8 shows a routine for displaying the first digit on the seven-segment LED display section of the display device 72. First step #
The jam trouble flag is checked in step 53, and if the jam trouble flag is set, the jam trouble type code is displayed in step #56, and if it is cleared, the sensor dirt display flag is checked in step #54. If the sensor dirt display flag is set, the sensor type code is displayed in the first digit in step #57. These type codes display numerical values by seven segments of LEDs, for example, the former displays 1 to 6, and the latter displays 1 to 5, respectively. If the flag is cleared in step #54, the first digit of the number of copies is displayed as usual in step #55.

In step #57, the sensor type code 1 to 5 is
There is a one-to-one correspondence between the register sensor 33 and the sensors 33 to 37. For example, if the registration sensor 33 is dirty, it is displayed in "dbi" including the display of the tens digit mentioned above.

FIG. 9 shows the sensor check timer count routine in step #32. In step #58, it is determined whether the sensor check timer is set. If it is set, the timer is counted down in step #59. If the timer has ended in step #60, a timer end flag is set in step #61.

According to the above-described embodiment, even when the sensors 33 to 37 are operating normally, the sensor 33 detects dirt on the sensors 33 to 37 and displays an alarm indicating that cleaning is necessary. It is possible to prevent the copying machine from stopping its operation due to abnormality detection due to contamination in items 37 to 37, and it is possible to avoid a situation where it takes a long time to restore the copying machine and becomes unusable during this period. In other words, sensor 3
By detecting that sensors 3 to 37 will become undetectable in the near future before they become undetectable, and cleaning the sensors 33 to 37 at this point, it is possible to prevent the copying machine from stopping for a long time. It can be avoided.

In the above-described embodiment, the levels of the output signals S2 to S6 at the time of sensor check are detected by the detection circuit during normal operation, but the output signal 3 at the time of sensor check is
A dedicated comparator or the like for detecting the levels of S2 to S6 may be used to adjust the detection level.Also, as a means for controlling the current of the light emitting element,
Various integrated circuits, relays, transistors, etc. may be used. The voltage applied to the light emitting element may be varied. As a means for warning that the sensors 33 to 37 are dirty, a display device other than those described above or a sounding device such as a buzzer may be used.

〔Effect of the invention〕

According to the present invention, with a simple configuration, it is possible to check the state of dirt on the optical sensor before it becomes undetectable, thereby cleaning the optical sensor and keeping equipment such as a copying machine in the best condition. becomes possible. Therefore, it is possible to prevent the operation of a device such as a copying machine from being stopped due to abnormality detection due to dirt on the optical sensor, and to avoid a situation where it takes a long time to recover and becomes unusable during this period. Can be done.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; FIG. 1 is a front cross-sectional view showing the general structure of a copying machine, FIG. 2 is a plan view showing the structure of the operation panel of the copying machine, and FIG. 3 is a sensor inside the copying machine. FIG. 4 is a flowchart showing the overall operation processing of the copying machine, and FIGS. 5 to 9 are flowcharts showing subroutines in the flowchart of FIG. 4 in detail. 33-37...Sensor (light sensor), 72...
Display section R (alarm means), 98...Sensor cleaning display section (alarm means), Q1-Q3...Switching element (current control means), Sl...Sensor check signal, 82-S6...Output Signal S. Applicant Minolta Camera Co., Ltd. Agent Patent Attorney Yukio Kubo Figure 7 Figure 8 Figure 9 S ES〉 #59 #6゜〉 #61

Claims (1)

[Claims] A checking device for an optical sensor comprising a light emitting element and a light receiving element, the apparatus comprising: current control means for reducing a current flowing through the light emitting element during checking compared to during normal operation; A light sensor checking device comprising: a level detection means for detecting whether an output level is above a certain level; and an alarm means for issuing an alarm when the output level of the light receiving element is not above a certain level.