JPS60196786A - Recorder - Google Patents

Abstract

PURPOSE:To control automatically the density of a developer in accordance with degradation of the developer by changing a set density level in accordance with elapse to control toner supply. CONSTITUTION:When a driving signal is supplied to an agitator driving motor of a developing device, integrating circuits 50-1-50-4 having set times TA, TB, TC, and TD (TA<TB<TC<TD) integrate elapse. Outputs of these circuits 50-1-50-4 are connected to AND gates 52-1-52-4, etc. through inverters 53-1-53-4, 51-1- 51-4, etc., and outputs of gates 52-1-52-4 go to the high level when the elapsed time is shorter than the time TA, equal to or longer than the time TA and shorter than the time TB, equal to or longer than the time TB and shorter than the time TC, equal to or longer than the time TC and shorter than the time TD, and equal to or longer than the time TD respectively, and a comparison reference value which is reduced in accordance with elapse is set to an operational amplifier 31, to which a toner density signal is supplied through a photodetector 29 and from which a toner supply signal is outputted, through resistances R1- R5. Consequently, the developer density is automatically controlled so that it is always constant in accordance with degradation of the developer accompanied with elapse.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording device using a developer,
Furthermore, the present invention relates to a recording apparatus that detects deterioration of developer and is controlled based on the detected output.

The developer used in recording devices such as electrostatic copying materials is a mixture of toner and carrier, and the toner is gradually consumed during development depending on the type and number of documents to be copied, and the toner concentration in the developer increases. That is, the developer concentration decreases.◇As a result, the image density on the copy paper becomes thinner. Therefore, toner is replenished, but in this case, if the toner concentration exceeds the appropriate level, the image density on the copy paper becomes too low, and at the same time, staining occurs.

Therefore, in order to continuously obtain copy images of good density, it is necessary to keep the mixing ratio of toner to carrier, that is, the density of the developer constant.

When the number of copies to be paid is small, copy images with good density can be obtained by keeping the developer concentration constant, but even if the developer concentration is kept constant, the cumulative number of copies increases. Accordingly, it becomes impossible to obtain a copy image with good density.

This is considered to be due to a deterioration phenomenon occurring in the developer. Various causes can be considered for the deterioration phenomenon of the developer, but the following are as follows.
The above causes will be explained together with a description of the reconnaissance device to which the present invention is applied.

In FIG. 1, an original glass stand 2 is provided on the upper surface of a copying apparatus 1, and an original 3 placed thereon is pressed onto the original glass stand 2 by a document presser 4 that can be opened and closed.

The original 3 is irradiated by the lamp 5, and the reflected light is imaged on the photosensitive drum 11 by the imaging lens 10 while the optical path is changed by mirrors 6.7 and 8.9.

The lamp 5 and mirror 6 move at a speed V in the direction of arrow S, the mirror 7 moves at a speed V/2 in the direction of arrow T, and the multi-purpose optical drum 11 rotates at a speed V in the direction of arrow U. Therefore, the image information on the document can be directly projected onto the photosensitive drum 11.

The photosensitive drum 11 is basically composed of a 4'JL support, a 4-layer optical layer, and an insulating layer, and has a corona charger 12.
The entire surface is uniformly charged in advance, and then subjected to the photoimage exposure and AC corona charge removal is performed by the AC frona discharger 13.Furthermore, the entire surface is uniformly exposed to light by the entire surface exposure lamp 14, and is statically charged according to the optical image. A latent image is formed. This electrostatic latent image is developed in a developing device 15 having a developer mainly composed of a predetermined charge and colored particles, and the developed image is transferred to a transfer paper 18 or 1 which is fed out from a cassette 16 or 17.
9, the image is transferred using the electric field generated by the transfer belt rd device 2o.

The image on the transfer paper 18 or 19 is fixed to the transfer paper by a fixing device 2, and the paper is discharged onto a tray 22. On the other hand 1 photosensitive drum. Flood particles remaining on the photosensitive drum xxli are removed and cleaned by a cleaning charge 23, and the photosensitive drum xxli is used repeatedly.

FIG. 2 shows the developing device 15 and its surroundings in J6 in FIG. 1, and shows the magnetic sleeve y1. 3 is a schematic diagram of developing an electrostatic latent image on a photosensitive drum 11 by an imager 15. FIG. Developer is supplied onto the photosensitive drum 11 by a fixed magnet 24 and a sleeve 25 rotating around it.
The electrostatic latent image is developed and visualized.

The carrier for the developer is, for example, pig iron powder F made by Nippon Iron Powder KK.
A magnetic material with low diffuse reflectance such as V250-400 is used, and the toner is made by melting and mixing a transparent resin such as polyester or polystyrene with an organic pigment or dye and, if necessary, a small amount of a control agent. A material with a high diffuse reflectance for moderately pulverized infrared rays (light from the lamp 27) is used.

The concentration of the developer layer consisting of carrier and toner as described above is detected on the developing sleeve by means of diffused radiation.

Of course, the detection may be performed at the developer falling portion A instead of on the sleeve as shown in the figure.

The developer moves in the direction of arrow P, and a transparent window 26 is provided so as to face the developer on the sleeve.
A lamp 27 (its power source is 27-1
) to irradiate the developer layer.

Since there is reflection from the developer depending on the appearance of the toner (when there is a lot of toner, there is a lot of reflected light), this reflected light is introduced into the light receiving element 29 via the infrared transmission filter 28 and converted into an electrical signal. .

This light-receiving element 29 may be any light-receiving element that is sensitive to infrared rays, such as a silicon light-receiving element or a PBS light-receiving element. A voltage source (3O) is applied to the other input of the arithmetic unit 31, and the arithmetic unit 31 forms an output signal corresponding to the difference between the reflected light signal and the reference signal.

Such an output signal is transmitted to the hopper 3 storing the replenishment toner 32.
3 is used as a signal for controlling the rotation of the motor 35 that rotates the screw 34 that replenishes toner to the developing device 15.

That is, when the toner density is high and the toner receives reflected light 1 exceeding a predetermined reflection value or within a predetermined range,
When the rotation of the motor 35 is stopped and the toner density is low and the reflected light is below the predetermined level, the signal line 31
-1 to rotate the motor 35 and replenish the developer 15 with the toner 32.

Further, the stirrers 36, 37 and the sleeve 25 are driven by a motor 38, which is driven by a drive signal derived on signal lines 39 to 1 of a control circuit 39. It is driven during the current appearance sequence of Soshiro. Further, the arithmetic unit 31 is controlled by the operation of the control circuit 39 so as to operate only while the motor 38 is being driven.

As described above, the developer is stirred during development.

Initially, the surface of the carrier is in the shape of a ridge, but as the 4-1-layer is agitated, the surface shape of the carrier changes and the resistance of the developer increases. Furthermore, since the toner is resin-based, it tends to adhere to the carrier.

Due to the above-mentioned factors, even if the developer concentration is kept constant, the copy density changes due to agitation of the developer.

Therefore, in the recording apparatus according to one embodiment of the present invention, the time period during which developer is supplied to the photosensitive drum (signal line 39
-1, the time during which the drive signal of the motor 38 is derived) is integrated, and when this integrated time reaches the set value, the copying machine is stopped, and the developer replacement lamp is turned on to prevent deterioration of recorded image quality. It is intended to prevent

FIG. 3 shows a control circuit applied to such a recording apparatus, and the terminal 40 is connected to the signal line 39-1 in FIG.
and apply a drive signal. The drive signal is applied to the pace electrode of the transistor 42 through the inverter 41, and the transistor 42 is set to OB'F.
The one shown in 3 is the Ir:C element (for example, Matsushita Electric KK's "O-A T 53 V", and clp = engineering px'
It has the characteristics of i'p.

Here, QT is the amount of charge charged to the integrating element, P is the current flowing through the integrating element, and the time during which the Tpid'ili current flows. The probe nX has a unique cent charge QS, and when time TS passes and Qp=qS, its impedance increases.

FIG. 4 shows the characteristics of the integration element for 1 degree. When q p =Q, S at time TS, the impedance of the integration element increases, so that the terminal voltage of V → to H.

When the transistor 42 is off, a current of IP--v--Ry flows through the integration element 43.

Therefore, in FIG. 2, the time during which the drive signal is derived onto the signal line 39-1 is changed to T1°T2. as shown in FIG. T
, 3.・・−= T= (T1+T2斗T3+−・・
-1Tn = TI), when TN-YL, the power of the integrating element increases and the transistor 44. Wow
,N,? A glance signal is derived from 1",', 1 child/15.

At the same time, the lamp 46 with a display of ``Current cum agent replacement'' is turned on, and a signal 1) is sent on the signal line 47 indicating the copying operation.

The double stop signal shown in Figure 1 is exactly the same type of stop signal that is derived when the full copy stop JJ button is pressed on a well-known ordinary copying machine. This voltage is applied to the recording device shown in FIG.

Therefore, if the alarm signal is derived as described above, then
This function not only displays the "developer replacement indication" but also stops the copying operation.

In the embodiment described above, the signal line 3 in FIG.
By applying the drive signal on 9-1 to the terminal 40,
Although the time taken to supply the developer to the photosensitive drum 11 is measured, in another embodiment, the time taken to supply the replenishment toner 32 from the hopper 33 to the developing device 15 may be measured.

To measure this time, it is sufficient to apply a drive signal on the signal line 31-1 to the terminal 40 in FIG. 3.

In yet another embodiment of the present invention, the set level of the developer concentration adjusting device may be changed over time.

No. G [>ff indicates such an embodiment, and 50
3 shows an integrating circuit similar to the integrating circuit surrounded by dotted lines in FIG. 3.
The integration time of integration circuit 50-2 is set to TA, the integration time of integration circuit 50-2 is set to TBjC, the integration time of integration circuit 50-3 is set to To, and the integration time of integration circuit 50-4 is set to TBjC.
111Jlt TD K Setting L Te, IH & Le 4
Q) There is a T.

These set times are set in advance to be TA, (TB(TO(TD).

The outputs of the integration circuits 50-1 to 50-4 are applied to AND gates 52-1 to 52-4 via inverters 5j-1 to 53 4, 51 1 to 51-4, respectively, and the 7B power of the AND gates is applied to the AND gates 52-1 to 52-4. , or the output of the input (-) 53-4 is connected to the resistors R1-R5 (
R3).

One input terminal 3 of the operational amplifier 31-4 is connected by a resistor R8 and a resistor R7 inserted between the point 54 and the power supply VCC.
Since the reference voltage applied to 1-3 is determined, and the resistor R7 is set to a constant value, the reference voltage BE is determined by the resistor R8.

Note that the input terminal 31-2 of the operational amplifier 31-4 has a 1
The impedance of the light receiving element 29 and the component of the power supply voltage VCC divided by the resistor R8 are applied.

Therefore, if the drive signal on the signal line 39-1 in FIG. Vcc) and the outputs of the other AND gates 52 become low level (0), so a voltage El obtained by dividing the voltage Vcc by the resistors R1 and R7 is applied to the point 54.

After the cumulative time of the drive signal reaches TA until it reaches TE, only the output of the AND gate 52-2 is at a high level, and the outputs of the other AND gates 52 are at a low level, so the voltage Vcc is connected to a resistor. Voltage E divided by R2 and R7
2 is applied at point 54Fc.

After the cumulative time of the drive signal reaches TB until it reaches To, only the output of the AND gate 52-3 is at a high level and the outputs of the other AND gates 52 are at a low level, so the voltage Vcc is connected to the resistor. A voltage E3 divided by R3 and R7 is applied to a point 54. After the cumulative time of the drive signal reaches To and until it reaches TD, only the output of the controller 52-4 is at a high level, and the other Since the output of the AND gate 52 is at a low level, the voltage E obtained by dividing the voltage Vcc by the resistors R4 and R7
4 is applied to the point 54.0 After the cumulative time of the drive signal reaches TD, the outputs of all the AND gates 52 become low level, and a high level (Vcc) is applied only to the resistor R5, and the voltage 7cc is applied to the resistor. R5
A voltage E5 divided by and R7 is applied to point 54.

The voltage I is as shown in FIG.
IC4) The said resistance is R1<R2<R3(
R4 (R5), so the concentration of the developer controlled by the automatic concentration adjustment device is determined by the time T.
A, TE, etc. are controlled to increase sequentially as the values progress.

That is, the operational amplifier 31 derives a drive signal (toner replenishment signal) onto the signal line 31-1 when the voltage applied to the terminal 31-2 becomes higher than the voltage applied to the terminal 31-3. , the developer concentration is controlled to increase as the reference voltage applied to the terminal 31-2 decreases.

In addition, in the embodiment shown in FIG. 6, a case has been described in which the drive signal on the signal line 39-1 in FIG. 2 is applied to the terminal 55, but instead of applying such a drive signal, the terminal 55 is A drive signal on the signal line 31-1 may be applied to the signal line 31-1.

As described above, according to the present invention, the deterioration of the developer can be automatically detected, so that a deterioration in recording quality can be notified before it occurs.

Further, according to the embodiment of the present invention, since the concentration of the developer can be automatically controlled according to the deterioration of the developer, it is possible to obtain good recording even after the developer has deteriorated. It is.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a recording apparatus to which the present invention is applied, FIG. 2 is a cross-sectional view showing the developing device in FIG. 1 in more detail, and FIG.
4 is a characteristic diagram of an integrating element, FIG. 5 is a waveform diagram showing drive signals, FIG. 6 is an automatic density adjustment circuit diagram to which the present invention is applied, and FIG. The figure is number 6
FIG. 4 is a density setting level characteristic diagram for explaining the operation of the figure. Here, D is a developer, 11 is a photosensitive drum, 15 is a developing device,
27 is a lamp, 29 is a light receiving element, 30 is a reference voltage source, 3
1 is a computing unit, 32 is a replenishment toner, 35.38 is a motor,
39 is a control circuit, 42 and 44 are transistors, 43 is an integrating element, and a 55-digit integrating circuit. η D9 7C Procedural Amendment (Buwi) April 2, 1985 1, Indication of the case 1982 Patent Application No. 124948 2, Invention title recording device 3, Person making the amendment Related Patent applicant address 3-30-2 Shimomaruko, Ota-ku, Tokyo Name (100
) Canon Co., Ltd. Representative Kaku 11i2 3 Part 4, Agent address: 3-30-25 Shimomaruko, Ota-ku, Tokyo 146, Date of amendment order (shipment date) March 26, 1985 6, Maps subject to amendment Side 7, Contents of amendment: Engraving of the drawing originally attached to the application, as shown in the attached sheet (no change in content)

Claims (1)

[Claims] In a recording apparatus having a developer concentration adjustment device that replenishes toner when the developer concentration decreases below a predetermined concentration level and controls the developer concentration so that the developer concentration matches a predetermined set concentration level, the settings are adjusted over time. A recording device characterized by changing density levels.