JPH02221980A - Detector for magnetic developer quantity - Google Patents

Abstract

PURPOSE:To prevent misdetection just after the start of the quantity detection of storing magnetic developer by providing a means which stops the detection of storing quantity of the magnetic developer within a definite time after the start of the operation of a stirring part. CONSTITUTION:The storing quantity of magnetic developer in a developing device is detected according to the outputs from a sensor part. When the developer is insufficient, a signal output part generates a forcedly stopping signal. Driving signals to a stirring member driving part are also inputted to a detection stopping means. The detection stopping means outputs detection starting signals to a detection part after the definite time lapses since the driving signals are inputted. Consequently, after the way that magnetic developer is stored in the developing device is uniformized by the action of the stirring member, the storing quantity detection of the magnetic developer starts. Thereby, under condition where developer is irregularly stored, no quantity detection is performed.

Description

Detailed Description of the Invention (a) Industrial Application Field This invention is used in an image forming apparatus using electrophotography to detect the amount of magnetic developer stored in a developing device. Regarding equipment.

(bl) Conventional technology In order to maintain a good image forming state in an image forming apparatus using electrophotography, it is necessary to store a sufficient amount of developer in the developing device. The amount of developer in the device is detected, and when the remaining amount of developer is low, a warning is displayed on the operation panel to urge replenishment of developer.In the developing device that stores magnetic developer as this developer, As shown in FIGS. (A) and CB), there is one in which a magnetic developer amount detecting device 8 is provided on the outer wall of the developing device 1 on the developer storage chamber 5 side. The magnetic developer amount detecting device 8 is provided with a detecting member 9 therein so as to be swingable with its upper end as a fulcrum. A magnet 10 is fixed to a part of the detection member 9 so as to be able to come into contact with the outer wall surface of the developing device 1 .

As shown in FIG. 9(A), the developer storage chamber 5 of the developing device 1
When a sufficient amount of magnetic developer 7 is stored, the magnet 10 is attracted to the magnetic developer 7, and the detection member 9 swings to a position where the magnet 10 contacts the outer wall surface of the developing device 1. When the storage amount of the magnetic developer 7 in the developing device 1 decreases, the magnet 10 stops magnetically attracting the magnetic developer 7 as shown in FIG. 9(B), and the detection member 9 moves to the position shown in the figure due to its own weight. Move up to. The displacement of the detection member 9 due to the storage amount of the magnetic developer 7 is measured by the phototransistor 1.
) etc., and the amount of magnetic developer 7 stored in the developing device 1 is known.

When the amount of magnetic developer 7 stored in the developing device l decreases, if the magnetic developer 7 remains attached to the inner wall surface of the storage chamber 5, the magnet 10 will remove the magnetic developer 7 attached to the inner wall surface.
Since the detection member 9 is displaced to the position shown in FIG. 9(A), the storage amount of the magnetic developer 7 cannot be accurately detected. 4 is rotatably provided to scrape off the magnetic developer 7 adhering to the inner wall surface of the storage chamber 5.

When a sufficient amount of magnetic developer 7 is stored in the storage chamber 5, the magnetic developer 7 easily flows into the detection device B side of the storage chamber 5 even when the stirring member 4 rotates. )
10 remains magnetically attracted to the wall surface of the developing device 1. As the amount of magnetic developer 7 stored in the storage chamber 5 decreases, the magnetic developer 7 adhering to the inner wall surface of the storage chamber 5 is scraped off by the stirring member 4, and then new magnetic developer 7 is added. Sufficient time is required for the magnetic developer 7 to flow into the detection device 8 side of the storage chamber 5, and immediately after the stirring member 4 passes the inner wall surface on the detection device 8 side, it separates from the outer wall surface of the developing device 1, and the magnetic developer 7 flows into it. Later, it will stick to the outer wall again. Furthermore, when the magnetic developer 7 is almost completely exhausted in the storage chamber 5, the magnetic developer 7 does not flow into the detection device 8 side of the storage chamber 5 (and the magnet 10 remains separated from the outer wall surface of the developer bag y1). When the magnet 10 approaches and separates from the outer wall surface of the developing device 1 in this way, the ratio of the on/off time of the phototransistor 1) in a certain period of time changes depending on the amount of magnetic developer 7 stored in the storage chamber 5. Change. This phototransistor 1)
storage chamber 5 by measuring the on/off time ratio of
Therefore, the conventional magnetic developer amount detection device detects when the amount of magnetic developer 7 stored in the storage chamber 5 falls below a certain amount. At this time, it is considered that a warning prompting the replenishment of magnetic developer is displayed, and the operation of the image forming apparatus is forcibly stopped when almost all the magnetic developer 7 in the storage chamber 5 is used up.

(C) Problems to be Solved by the Invention However, in the developing device equipped with the above-mentioned conventional magnetic developer amount detection device, the magnetic developer is uniformly distributed in the storage chamber when the stirring member is stopped in the developing device. It may not be possible to replenish. For example, if the replenished magnetic developer is not on the detection device side of the storage section, the replenished magnetic developer will not move to the detection device side until the stirring member rotates. In such a case, even if the magnetic developer is replenished into the storage chamber, the magnet will not be able to attract the outer wall of the developing device until the stirring member starts rotating, resulting in a state where no magnetic developer is stored. Since the machine is forcibly stopped when it is determined that the machine is not working properly, there is a problem in that even if the magnetic developer is replenished, the image forming operation cannot be performed.

An object of the present invention is to start detecting the amount of magnetic developer stored after the storage state of the magnetic developer is made uniform in the developing device after power is turned on to the image forming apparatus. (d) Means for Solving the Problem The magnetic developer amount detecting device of the present invention provides a magnetic developer amount detecting device that can prevent detection. A magnetic developer amount detection device for detecting the amount of magnetic developer is characterized in that a detection stop means is provided for stopping detection of the amount of stored magnetic developer until a predetermined period of time has elapsed after the start of operation of the stirring member.

(e) Function The function of the present invention will be explained using FIG. 1. The magnetic developer amount detection device detects the amount of magnetic developer stored in the developing device according to the output of the sensor section, and detects the amount of magnetic developer stored in the developing device. When the magnetic developer runs out, a forced stop signal is output from the signal output section. The drive signal supplied to the stirring member drive unit is also input to the detection and stop means. The detection stop means measures a certain period of time from the time when this drive signal is input, and outputs a detection start signal to the detection section when the certain period of time has elapsed. In other words, since a detection start signal is supplied to the detection unit after a certain period of time has elapsed after a drive signal is supplied to the stirring member drive unit, the storage state of the magnetic developer in the developing device is determined by the operation of the stirring member. After the amount of magnetic developer is made uniform, detection of the amount of stored magnetic developer is started. Therefore, the amount of magnetic developer stored in the developing device is not detected even if the magnetic developer is not stored uniformly, and a forced stop signal is not outputted from the signal output section after replenishing the magnetic developer.

('') Embodiment FIG. 2 is a schematic diagram showing the configuration of a copying machine equipped with a magnetic developer amount detection device according to an embodiment of the present invention.

A photosensitive drum 22 is pivotally supported in the center of the interior of the copying machine 21, and constitutes a copying process section 26 together with the developing device 1, the charger 23, the transfer charger 25, etc. provided on the outer periphery of the photosensitive drum 22. A document table 27 is provided on the top surface of the copying machine 21, and an optical system device including a copy lamp 28 is provided below the document table 27.

Further, a paper cassette 18 is attached to one side of the copying machine 21, and together with a paper feed roller 17, constitutes a paper feed section 15. From this paper feed section 15 to the copying process section 26
Rollers 12 and 13 are provided between the two, and a paper conveyance path 16 is formed.

The developing device 1 includes a photosensitive drum 22 that is charged and exposed to light.
A magnetic developer is supplied from a magnet roller 2 onto the surface of the magnetic roller. Further, a stirring member 4 is provided inside the developing device 1 , and this stirring member 4 receives rotational force from a stirring motor 42 . The photosensitive drum 22 receives rotational force from the main motor 41 . The rotational force of the main motor 41 is also transmitted to the rollers 12, 13 and the paper feed roller 17 via a transmission mechanism (not shown).

Furthermore, as will be described later, a developer detection device 8 is attached to the developing device 1, which includes a developer detection member 9 and a photosensor including a phototransistor and an LEolo. This detection device 8 detects that when there is sufficient developer in the developing device, the phototransistor outputs "LO" (see FIG. 9 (A)), and when there is not enough developer, the phototransistor outputs "LO". In reality, the stirring member 4
As the detection member rotates, the detection member swings, so it is possible to determine how low the output of the phototransistor is within a certain period of time.

The amount of developer is determined by calculating whether it is in the "°" state or the "Hi" state (in this embodiment, the ratio of the two is looked at).

FIG. 3 is a block diagram of the main parts of the control section of the copying machine.

Drivers 35 to 39 are connected to the CPU 31 via an I10 interface 34. This driver 35~
39 includes a main motor 41 charger 23
．． 25. Developing device 1) A copy lamp 28 and a stirring motor 42 are connected. The CPU 31 executes the drivers 35 to 39 according to the program written in the ROM 32 in advance.
The drivers 35 to 39 drive each device based on this control data. Further, the result of comparing the output of the phototransistor 1) with a reference value is input to the CPU 31 via the I10 interface 34.

In addition, as shown in the memory map of FIG.
Memory areas MAI to MA6 of RAM33 connected to
are assigned an interrupt counter CNT, a low level counter LC, a high level counter HC, a replenishment warning counter TNEC, a replenishment warning flag TNEF, and a forced stop counter TEC.

FIG. 5 is a diagram showing the configuration of some circuits attached to the CPU 31. The flip-flop 53 is set or reset by a set signal or a reset signal output from the CPU 31, holds its output, and inputs it to the AND gate 51. Further, the timer 52 outputs a signal to the AND gate 51 at a constant cycle. The AND gate 51 performs a logical product of the signal of the timer 52 and the output of the flip-flop 53, and outputs the result to the CPU 31 as a timer interrupt signal S1.

6 and 7 are flowcharts showing the processing procedure of the control section of the copying machine, with FIG. 6 showing the main routine and FIG. 7 showing the timer interrupt routine.

When the power is turned on to the copying machine 21, initialization is performed such as clearing each memory area of the RAM 33 (
nl), drives the stirring motor 42 at a predetermined timing (n2), and starts a timer T1 allocated to the memory area MAY of the RAM 33 (n3) - the timer 'r1 measures a time t1 to be described later. When this time t1 has elapsed, the storage amount of magnetic developer is detected. This time t1 corresponds to the fixed time of the present invention. This timer T
1 times up, the CPU 3t outputs a set signal to the flip-flop 53 (n4 to n5).

Next, warming-up is performed, including a process to raise the temperature of the fixing device (not shown) (n6), and when the warming amplifier is completed, the printer waits for the print switch to be operated (n7).
When the print switch is operated, the main motor 41 charger 23.25 is driven, and a developing bias is applied to the developing device 1 (n8 to n1O). After that, the paper is fed from the paper feed section at a predetermined timing (n1l). ), the copy lamp 28 is turned on and the optical system device is moved to the lower surface of the document table 27 (n12, n13), and the timing roller 13 is driven at a predetermined timing to move the fed paper into the copy process section 26. (n14) - The developer image formed on the photoreceptor drum 22 is transferred to the surface of the paper transported to the copying process section 26 at the position of the transfer charger 25, and then transferred to the paper ejection section via the fixing device. is discharged. When the optical system device reaches the end of the document, it moves back and forth on the lower surface of the document table 27 (n15), and at the same time, the copy lamp 28 is turned off (n16). Above n8~n
16 is executed continuously for the set number of sheets, and when the processing of the set number of sheets is completed, the supply of the developing bias to the developing device 1 is stopped, and the driving of the charger 23, 25 and the main motor 41 is stopped. 17→n
18-n 20), returns to the print switch operation standby state.

During the processing of the above main routine, when a set signal is output to the flip-flop 53 at n5, the timer 52 (
5) is output from the AND gate 51 as a timer interrupt signal S1, and the timer interrupt routine shown in FIG. 7 is entered. In this timer interrupt routine, first the RAM
The interrupt counter CNT assigned to the memory area MAL of No. 33 is decremented and its contents are checked (n31, n32). This counter counts the number of times there has been an interrupt. In other words, this counter monitors the elapse of a certain period of time necessary for detecting the developer storage amount. If the content of the interrupt counter CNT is not O, the output state of the comparator 40 is read (n33). When the output of the comparator is "LO", that is, in the state shown in FIG. In that case,
In other words, in the state shown in FIG. 9(B), the memory area MA
The high level counter HC assigned to 3 is incremented (n34 to n36), and the process returns to the main routine.

The interrupt counter CNT has a fixed number (255 in this embodiment) corresponding to a fixed time in the nl initialization process.
is stored, and when the contents of the 0 interrupt counter CNT which executes the above-mentioned processes n31 to n36 a certain number of times reaches 0, the certain measurement time has ended, so the high level counter HC corresponding to the contents of the low level counter LC is Find the ratio K of the contents (n32→n37), this ratio K is the reference value A
Replenishment is not necessary if it is below. In this case, RAM
The value 10 is sent to the replenishment warning counter TNEC assigned to the memory area MA4 of 33 (n38→n
39). Setting the same counter to 10 means
This means that the TNEC has been initialized, which means that replenishment is not necessary. Next, the replenishment warning flag TNEF assigned to the memory area MA5 is reset, and the value 5 is set to the forced stop counter TEC assigned to the memory area MA6 (n
40. n41), adding 5 cents to this TEC also means initializing the TEC. Please clear the low level counter LC and high level counter HC n42. n43), the value 255 is set in the interrupt counter CNT.
(n44) and returns to the main routine.

If the ratio K obtained in n37 exceeds the reference value A, the replenishment warning counter TNEC is decremented (n45), and if the content of this replenishment warning counter TNEC is not 0, the above processes n4O-n44 are executed. Return to main routine. The lower the content of TNEC, the lower the amount of developer. However, development work is still possible.

In n46, the content of the replenishment warning counter TNEC is 0.
If so, the replenishment warning flag rNEF is set and the content of the forced stop counter TEC is decremented (n
47. n4B), a decrease from the contents of this TEC indicates that the amount of developer has decreased considerably. Then, check the contents of the forced stop counter TEC n4
9) If the content of the forced stop counter TEC is not 0, the process returns to the main routine from n42 to n44, but if the forced stop counter TEC is 0, a reset signal is output and interrupt processing is prohibited. n50), the drive of the main motor 41, etc. is forcibly stopped. At this stage, it is no longer possible to guarantee the quality of development.

In the above, the processes n3 to n5 together with the configuration shown in FIG. 5 correspond to the detection stop means in FIG. 1.

As described above, according to this embodiment, as shown in FIG. 8, driving of the stirring motor 42 is started when time ta has elapsed after the copying machine 21 is powered on. As a result, the stirring member 4 shown in FIG. 9(A) starts rotating, and the magnetic developer 7 is housed in a uniform state inside the developing device 1).

When a predetermined time t1 measured by a timer Tl has elapsed from the start of driving of the stirring motor 42, a cent signal is outputted to a flip-flop 53 shown in FIG. By outputting this set signal, the signal of the timer 52 becomes an interrupt signal to the CPU, and the timer interrupt routine shown in FIG. 7 is executed.

As is clear from FIGS. 9(A) and 9(B), when a sufficient amount of magnetic developer 7 is stored inside the developing device 1, the detection member 9 blocks the light receiving path of the phototransistor. , its output goes to low level. On the other hand, as the amount of magnetic developer 7 stored in the developing device 1 decreases, the detection member 9 no longer blocks the light receiving path of the phototransistor, and its output becomes high level. In the timer interrupt routine shown in FIG. 7, the output level from the phototransistor 1) is read for a negative number of times (255 times), and the ratio between the high level and the low level is calculated using the low level counter LC and high level counter HC. seek. As shown in FIG. 8, the output of the phototransistor 1) changes from a state where a sufficient amount of magnetic developer 7 is stored in the developing device 1 to A-+B-C as the amount of the magnetic developer 7 gradually decreases. , the high level output time for a certain period of time gradually becomes longer.

A replenishment warning counter TNEC and a forced stop counter TEC detect changes in the output level of this phototransistor 1).
When the storage amount of the magnetic developer 7 in the developing device 1 falls below a certain amount, a replenishment warning flag TNEF is set and a display prompting replenishment of the magnetic developer 7 is displayed on the display panel. Do it like this. Further, when it is detected that the remaining amount of the magnetic developer 7 in the developing device 1 is almost gone, the driving of devices such as the main motor 41, charger 23, 25, copy lamp 28, etc. is forcibly stopped, and the magnetic developer 7 is Waiting for replenishment.

Note that after the forced stop process is performed, when the magnetic developer 7 is replenished and a reset button (not shown) is operated, the process is executed from the first address of the main routine. Therefore, even after replenishing the magnetic developer, the stirring motor 42 rotates for a certain period of time tl, and after the stirring member 4 makes the storage state of the magnetic developer side 7 in the developing device 1 uniform, the seventh
The timer interrupt routine shown in the figure is executed.

(g1 Effect of the invention According to this invention, the stirring member operates for a certain period of time in the developing device, and the storage amount is detected after the storage state of the magnetic developer in the developing device becomes uniform. No false detection occurs immediately after the start of detection.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the operation of the present invention, Fig. 2 is a schematic diagram showing the configuration of a copying machine equipped with a magnetic developer amount detection device according to an embodiment of the invention, and Fig. 3 is a control section of the copying machine. 4 is a memory map of the main part of the RAM that constitutes a part of the control section of the copier, FIG. 5 is a diagram showing a part of the circuit of the control section, and FIG. FIG. 7 is a flowchart showing the processing procedure of the main routine of the control section, FIG. 7 is a flowchart showing the processing procedure of the timer interrupt routine of the control section of the copying machine, and FIG. 8 is the developing device and magnetic developer amount detection of the copying machine. Timing chart of the device, Figure 9 (A) and (B)
) is a diagram showing a developing device provided in a copying machine to which the present invention is applied. 1-developing device, 4-stirring member, 7-magnetic developer 8-detecting device.

Claims (1)

[Claims] (1) In a magnetic developer amount detection device that detects the amount of magnetic developer stored in a developing device equipped with a stirring member, the amount of stored magnetic developer is detected within a certain period of time after the stirring member starts operating. A magnetic developer amount detecting device characterized by being provided with a detection stopping means for stopping detection.