JPS6129502B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrostatic device control device that reads out an electrostatic latent image formed on a photoconductor of a device having a photoconductor and controls the formation of the electrostatic latent image on the photoconductor. It is something.

Electrostatic devices such as electronic copiers or electrostatic printers use corona discharge, Se, Cds, etc. photoreceptors, but these are directly affected by temperature, humidity, changes over time, etc. The electrostatic latent image formed varies considerably even if the exposure amount, the voltage applied to the corona discharger, etc. are constant.

Therefore, even when such an electrostatic latent image is visualized using toner, the image obtained by visualization is unstable.

In order to stabilize the image obtained by visualization in this way, it is necessary to stabilize the electrostatic latent image, and for this purpose it is necessary to stabilize the electrostatic latent image formed on the photoreceptor. The electrostatic latent image can be controlled by detecting the image and controlling a corona charger or the like according to the detection output.

The present invention provides a recording apparatus that forms a charge image on an electrostatic latent image forming member and then visualizes the charge image.
A first charge image in a bright area and a second charge image in a dark area are formed by irradiating the electrostatic latent image forming member with light having a predetermined intensity, and the first charge image and the second charge image are formed on the electrostatic latent image forming member. A first signal corresponding to a charge image of two and a second signal corresponding to a charge image of
The second signal corresponding to the dark area controls the charging conditions for the electrostatic latent image forming member, and the first signal corresponding to the bright area controls the exposure conditions for forming the latent image or the latent image microscope. The present invention provides an image stabilizing device characterized by controlling development conditions for imaging.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1A is a side view showing the main parts of an electrostatic copying apparatus. It is composed of three layers: an insulating layer 12, a photoconductive layer 13, and a conductive substrate 14, and the photosensitive drum 11 is charged positively when the photoconductive layer 13 is N type and negatively charged when it is P type. It is something. Incidentally, FIGS. 2A and 2B show the cross section of the photosensitive drum and its equivalent circuit, and the insulating layer 12 is connected to the parallel circuit of the resistor R12 and the capacitor C12, and the photoconductive layer 13
are resistor R13, capacitor C13, and diode D13
(However, when no light is irradiated) it can be replaced with a parallel circuit.

Therefore, if the DC voltage obtained from the DC power supply 15 is applied to the corona charger 16 via the switch SW1, the photoreceptor 1 will be charged at the end of the primary charging.
Charges exist on 1 as shown in FIG. 3A.

If we describe it in terms of an equivalent circuit, primary charging is shown in Figure 3B.
As shown in the figure, this is equivalent to connecting the DC power supply 15 between the terminals T and T', and is equivalent to charging the capacitors C12 and C13.

Next, a DC voltage with a polarity opposite to that during the primary charging is applied from the power supply 18 to the corona static eliminator 17 via the switch SW2, and light 20 obtained from the light source 19 is irradiated via the half mirror 21. do.
(The state at this time is shown in FIG. 8A) Such a light source 19
has a lamp 22 and an optical system 23 that forms the light from the lamp 22 into a slit shape, and a current from a DC power source 24 is applied to the lamp 22 via a gate 25 to turn the lamp 22 on. It is what is being driven.

The gate 25 as described above is controlled by the output of an oscillator 26 which oscillates a rectangular wave of a constant frequency via a switch SW6.
When the rectangular wave is at a high level, the gate 25 is closed and the lamp 22 is turned off, and when the rectangular wave is at a low level, the gate 25 is opened and the lamp 22 is turned on. Therefore, if the duty of the rectangular wave is 50%, there will be stripes across the area D on the photoreceptor 11 as shown in FIG. 8B (the shaded area is the area irradiated with the light 20). Simultaneous exposure is performed in a similar manner. Note that the light intensity of the light 20 is determined by the original platen 2, which will be described later.
It is preferable that the light intensity be approximately equal to the light having the strongest light intensity among the light 29 reflected from the document 30 on the document table 27 when the light 7 is irradiated by the lamp 28.

By performing the charge removal and light irradiation as described above, the charge on the portion irradiated with light disappears, and the charge remains on the portion that is not irradiated with light, as shown in FIG. 4A.

If we explain it using an equivalent circuit, the part where only static electricity has been removed is the terminal T, as shown in Figure 4B.
It is equivalent to a short circuit between T' and the capacitance C12
A part of the charge moves to the capacitor C13, which is equivalent to being charged as shown in the figure.

On the other hand, the area where the static electricity was removed and where the light was irradiated is further connected to the diode D1 as shown in Figure C.
3 is short-circuited, and the capacitance C12, C
This is equivalent to all 13 charges becoming zero.

Next, when the entire surface is exposed using the lamp 32 to which DC is applied from the DC power supply 31 via the switch SW3, as shown in FIG. The area hit will remain in that state.

Explaining this using an equivalent circuit, full-surface exposure is equivalent to short-circuiting the diode D13, so in areas that are not exposed to light, the charge in the capacitor C13 is discharged as shown in FIG. 5B, and in areas that are exposed to light, As shown in FIG. 5C, the state remains unchanged.

Therefore, in FIG. 4B, the surface potential of the photosensitive drum with respect to the conductive substrate 14 was close to zero, but in FIG. 5B, the surface potential increases by the amount of charge stored in C12, and the contrast improves. .

In this way, an electrostatic latent image is formed on the photoreceptor 11, but in the above explanation, it is well known that AC static elimination may be performed instead of DC static elimination. be.

Reference numeral 33 designates a corona static eliminator which has the same configuration as that shown at 17 and is irradiated with light from a lamp 35, and includes the aforementioned electrostatic latent image forming means (corona charger 16, corona static eliminator 17, light 20, lamp 3
The electrostatic latent image formed on the photoreceptor 11 by 2) is
The electrostatic latent image is read out by discharging the latent image charge and leading it to the terminal 39 as a potential between the conductive substrate 14 and the resistor 38 connected between the conductive substrate 14 and the ground.

A static eliminating voltage is applied to the static eliminator 33 from the DC power source 34 via the switch SW4, and the lamp 35 applies current from the DC power source 37 to the static eliminator 33 via the switch SW5.
The voltage is applied via the .

If such static elimination is explained using an equivalent circuit, it will be as shown in FIG. 6. In the area where no light hits, the charge in the capacitor C12 is discharged as shown in FIG. 6B, and a current C1 flows through the resistor 38. This allows terminal 3
A voltage of 39 can be obtained at 9.

On the other hand, in the area exposed to the light, as shown in FIG. 6C, no charge is held in the capacitor C12, so no discharge current flows.

The switches SW4 and SW5 are turned on after a certain period of time t1 after the electrostatic latent image is formed on the photoreceptor 11 by the electrostatic latent image forming means, and the switches SW1 and SW5 are turned on at the same time as this turning on or a minute period in advance.
Turn SW2 and SW3 OFF, and switch SW6
is turned OFF to stop applying the oscillation output of the oscillator 26, and the gate 25 is closed to stop the lamp 22 from emitting light.

During the time t1, at least one striped latent image is formed on the photoreceptor 11 rotating in the direction of arrow S at a constant circumferential speed.
Since the time required to form a period equal to or longer is set, if the striped latent image formed on the photoreceptor 11 in this way arrives at the position corresponding to the static eliminator 33, the static electricity is removed and the light is removed. Since the irradiations are performed simultaneously, the charges on the photoreceptor 11 are discharged, and this discharge current flows through the resistor 38.

Therefore, a rectangular voltage signal can be obtained at the terminal 39, for example as shown in FIG. 9A, which has a rectangular shape and changes between voltage levels V1 and V2.

Incidentally, V1 is the charge image formed in the area irradiated with the light 20 (theoretically it should be OV, but in reality, a charge is formed in the area irradiated with the light 20 like this, so it is is called the bright charge image) V2
corresponds to a charge image formed in an area not irradiated with light 20 (referred to as a dark charge image). Therefore, by controlling the voltage of the power source 15 using the voltage V2 and controlling the intensity of light irradiated onto the photoreceptor 11 using the voltage V1 (reflected light 29
The most preferable electrostatic latent image can be formed on the photoreceptor 11 by controlling a diaphragm 46 inserted in a part of the optical path of the photoreceptor 11 with a servo motor 47.

After reading out the electrostatic latent image necessary for control in this way, switch SW1, SW2, and SW3 are turned on again.
CN, and switch SW7, which controls the lamp 28 that illuminates the document table 27, is turned on, and the power source 41 is turned on.
A current is applied to the lamp 28 to turn it on. When the area on the photoreceptor 11 charged by the charger 16 (the voltage for this area has already been determined to perform the most preferable charging) reaches at least a position facing the static eliminator 17, the document platen drive motor is activated. By moving the document table 27 on which the document is placed in the direction of the arrow M by driving M with the switch SW11, the light 29 reflected by the document (of course it may be transmitted) is reflected by the mirror 42. let me,
In addition, the aperture 46, which has already been controlled to pass an appropriate amount of light, and the half mirror 21 circle are used to irradiate the static electricity removal position as the slit light SU shown in FIG. It is something that can be entered. Further, when the document table 27 starts to move, the switches SW4 and SW5 are also turned off to stop the static elimination for reading out the latent image.

Therefore, as is well known, the information latent image formed on the photoreceptor 11 by the light 29 is transferred to the developing device 43.
After being visualized with toner in the transfer device 4
4, transfer the toner image onto a transfer paper (not shown),
The remaining toner on the photoreceptor is removed by a cleaning blade in preparation for forming a reproduced image on the photoreceptor 11.

The control of each switch as described above is carried out, for example, by the 10th switch.
This can be realized by a circuit as shown in the figure.

50 to 53 indicate times T1, T2, and T, respectively.
3, T4, and outputs a high level signal to the signal lines L1 to L4 during the time period. Such signal lines L1 to L4 are signal lines C1 to
They are formed in a matrix with C7 and C11, and the areas indicated by circles in the figure are signal lines L and C11.
are diode-coupled points.

Signal lines C1 to C7 and C11 are each switch SW
This is a signal line for controlling SW1 to SW7 and SW11.When a high level signal is derived from signal line C, the switch SW is turned ON, and when a low level signal is derived, it is turned OFF. .

The terminal 54 is a terminal that applies an initial signal derived by the first operation of the copy start button after the main switch of the copying machine is turned on, and the level is higher than that of the clock circuit 50 for a time T1 from the application of the initial signal. A signal (the other clock circuits 51 to 53 are low level signals) is derived.

Therefore, for the time T1 after the application of the initial signal, the switches SW1, SW2, SW3, and SW6 are turned on, and the other switches are turned off. However, switches SW4 and SW5 may be left ON if necessary.

This time T1 is the time to form a striped latent image for measurement, and the time t1 is the time required for the area of the photoreceptor 11 that corresponds to the charger 16 to face the lamp 32. The latent image formed by the lamp 22 after the elapse of the time T1 is located at least between the lamp 32 and the static eliminator 33.

Due to the fall of the output signal of the clock circuit 50,
The clock circuit 51 is driven, and a high level signal (other signal lines L1, L3,
L4 derives a low level signal).

Therefore, for T2 time, switches SW4 and SW5 are
It turns ON and other switches turn OFF.

This time T2 is the time to read out the latent image for measurement, and it is sufficient that it is sufficient time to obtain signals for reading out the bright latent image and the dark latent image formed by the lamp 22 on the terminal 39. be.

Due to the rise of the output signal of the clock circuit 51,
The clock circuit 52 is driven, and a high level signal is sent to the signal line L3 (other signal lines L1, L
2, L4 is a low level signal).

Therefore, for T3 time, switches SW1 to SW5, SW
7 is turned ON, and switches SW6 and SW11 are turned OFF.

Since the time T3 is the time for the next charging to form an information latent image, it is sufficient that the time T3 is equal to or longer than the time required for the area of the photoreceptor 11 facing the charger 16 to face the static eliminator 17. It is something.

Due to the rise of the output signal of the clock circuit 52,
The clock circuit 53 is driven, and a high level signal (other signal lines L1 to L3) is sent to the signal line L4 over time T4.
is a low level signal).

Therefore, during T4 time, switches SW1 to SW3, SW7, and SW11 are ON, and switch SW
4, SW5 and SW6 are turned OFF.

Since the time T4 has already entered the normal copying process, it may be sufficient time to carry out the well-known normal copying process.
The reflected light from the document table 27 is irradiated onto the photoreceptor 11 with a width of area D (FIG. 8A). Note that it is not necessary to measure the latent image and control the formation of the latent image based on the measurement results each time the document table 27 is moved, but after turning on the main switch that controls all the power supplies of the copying machine as described above. It may be performed only when the copy button is operated for the first time, only when a predetermined button is manually operated, or every time a predetermined number of copies are completed.

In the above embodiments, a photoreceptor having a three-layer structure was exemplified, but the present invention can also be applied to a photoreceptor having an insulating layer 12 removed from the photoreceptor 11 in FIG. 1, that is, a photoreceptor having a two-layer structure. It can be implemented similarly.

In this case, in order to form the electrostatic latent image shown in FIG. A circuit as shown in Figure B may be used,
The structure is extremely simple compared to the case where the three-layered photoreceptor shown in FIG. 1A is used.

The control circuit having such a two-layer structure as shown in FIG. 10 can also be used. However, signal line C
2, C3, and C5 are unnecessary.

In the embodiment shown in FIG. 1A, a case has been described in which a static eliminator 33 and a lamp 35 are newly added in addition to a normal copying machine. , the lamp 22 can also be used as is.

FIG. 7 shows such an embodiment, and the members labeled with the same numbers as in FIG. 1A are the same members as in FIG. 1A, and perform the same functions.

In this embodiment, switches SW8, SW9, and SW10 are newly added to serve as a static eliminator for forming an electrostatic latent image and a static eliminator for reading.

That is, when switch SW8 is turned on, gate 25 is turned on.
The current of the power supply 24 is applied to the lamp 22 regardless of the operation of the lamp 22.
, so the switch SW8
When the photoreceptor is turned on, a slit-shaped light SL is always irradiated onto the photoreceptor as shown in FIG. 8A.

Also, switches SW9 and SW10 are connected to developer unit 4, respectively.
3. This is a switch for stopping the function of the transfer device 44. When this switch is turned ON, the developing device and transfer device perform their original functions, and when turned OFF, their functions are stopped.

FIG. 11 shows in more detail the switch control circuit that controls each switch SW in the device shown in FIG. 7, and as explained in FIG. The lines cl1 to cl9 are diode-coupled at the points indicated by circles, and when a high level signal is derived to the signal lines cl1 to cl9, the corresponding switch SW is turned on.

Now, when a trigger signal is applied to the terminal 60, the clock circuit 61 is activated, a high level signal is derived to the signal line l1 for a time t1, the switches SW1 to SW3, and SW6 are turned on, and the switch SW7 is turned on. ~SW11 is turned OFF. Such time t1
is the time it takes to form a latent image of a striped pattern for measurement, so after the position on the photoreceptor 11 facing the charger 16 passes the position facing the lamp 32, the position on the photoreceptor 11 is changed slightly (at least one set). It is sufficient that the time is sufficient for the process to proceed until the above-mentioned bright area charge image and dark area charge image are formed, and the trigger signal may be generated by pressing the copy button after turning on the main switch of the copying machine (not shown). By pressing , a notification signal can be used to notify that the pre-rotation of the photoreceptor has been completed by a predetermined amount prior to the movement of the document.

The falling of the output signal of the clock circuit 61 drives the clock circuit 62, and a high level signal is derived only to the signal line l2 over time t2.

Therefore, during this time period t2, the switch SW
2. Only SW8 is ON, other switch SWs are
It becomes OFF.

Since this time t2 is the time to read out the measurement latent image, the tip of the striped electrostatic latent image formed on the photoreceptor 11 (the photoreceptor 11 is assumed to rotate at a constant speed in the direction of arrow S) It is sufficient if the time is sufficient for a sufficient amount of the light to pass through the static eliminator 17 to be read by the static eliminator 17. Due to this static elimination, terminal 3
9, a bright signal and a dark signal corresponding to the bright charge image and the dark charge image are obtained.

Due to the fall of the output signal of the clock circuit 62,
The clock circuit 63 is driven, and a high level signal is derived only from the signal line l3 over time t3.

Therefore, during the time period t3, the switch SW1~
SW3, SW7, SW9, and SW10 are turned on, and the other switches are turned off. This time t3 is a time for performing primary charging, and is sufficient as long as it is sufficient time for the portion facing the charger 16 to pass through the static eliminator 17.

Due to the fall of the output signal of the clock circuit 63,
The clock circuit 64 is driven, and a high level signal is derived only from the signal line l4 over time t4.

Therefore, during the time period t4, the switch SW
6. SW8 is turned off, the other switches are turned on, and the document table 27 starts moving.

Since the time t4 has already entered the normal copying process, it is sufficient that the time t4 is sufficient time to carry out the well-known normal copying process.

With the above configuration, bright area charges can be read out as voltage signals, and such voltages can be applied to a circuit as shown in FIG. 12 to control primary charging and exposure amount.

That is, since the terminal 39 in FIG. 12 is the terminal shown in FIGS. 1 and 7, a signal as shown in FIG. 13A is applied thereto as described above.

These signals are applied to the gate circuits 70 and 71, respectively, and the gate signal application terminal 3 of the gate circuit
9-2 are connected to the terminals 39-1 of the oscillator 26, respectively, and gate signals as shown in FIGS. 13B and 13C (however, the signal shown in FIG. 13C is inverted by the inverter 72) are applied. It is something. However, when the phases are not aligned as shown in FIG. 13, a delay circuit or a phase control circuit is inserted between the terminals 39-1 and 39-2 to make the phases coincide.

Since such gate circuits 70 and 71 derive the signals applied to their inputs to output lines 73 and 74 when high-level gate signals are applied, respectively,
The signals obtained on output lines 73 and 74 are respectively
It will look like Figures D and E. Therefore, if such signals are applied to the peak hold circuits 75 and 76 and held, level signals of V2 and V1 can be obtained on the output lines 77 and 78, respectively.

These level signals are applied to voltage comparators 79 and 80 and compared with the voltages applied by reference voltage applicators 81 and 82, respectively, and outputs corresponding to the difference are derived to output lines 83 and 84. .

The signal obtained on the output line 83 is used as a signal for controlling the power supply 15, and the signal obtained on the output line 84 is used to control the servo motor 47 to control the throttle 46. For example, the primary charging can be controlled by the dark charge on the photoreceptor, and the exposure amount can be controlled by the bright charge.

The output signal obtained on the output line 81 is sent to the decoder 8
3 to the output line 83-1 of the decoder 83.
- 83-7, any one output line is selected according to the applied signal.

Similarly, the output signal obtained on output line 82 is applied to a decoder 84, which output line 84-
Any one of output lines 1 to 83-7 is selected according to the applied signal.

Such output lines 83-1 to 83-7, 84-1 to 8
4-7 are applied to the power supply 15 and the servo motor 47, respectively, so if the power supply 15 is configured so that its output voltage changes according to the selected output line 83-1 to 83-7. For example, if the servo motor 47 is configured to rotate to a predetermined position according to the selected output line, the primary charging and the exposure amount can be automatically controlled.

As described above, according to the present invention, the dark area charge and the bright area charge are measured, and the charging condition is controlled by the former, and the exposure condition or development condition is controlled by the latter, so that image control can be performed extremely accurately. It is something.

In the above embodiment, only the exposure amount is controlled by the detection output of the bright charge image, but the bias voltage applied to the developing device 43 is controlled by the detection output to visualize the latent image. It is also possible to control the

In such a case, the developing bias voltage may be set based on the output of the decoder 84.

In addition, in the above embodiment, the circumferential speed of the photoreceptor was set to vcm/
sec, the distance between the latent image forming means and the measuring static eliminator.
dcm, and when one period of the oscillation signal of the oscillator is TDsec, by setting v/d>TD, the time required for measurement can be extremely shortened.

[Brief explanation of the drawing]

FIGS. 1A and 1B are block diagrams showing the main parts of the electrostatic device control device according to the present invention, and FIGS. 2A, 3A, 4A, 5A, and 6A are photosensitive 2nd cross-sectional view of a photoreceptor for explaining the formation of a latent image on a body
Figure B, Figure 3 B, Figure 4 B, C, Figure 5 B, C,
6B and 6C are equivalent circuit diagrams of a photoreceptor for explaining the formation of a latent image on the photoreceptor, and FIG. 7 is a block diagram showing the main parts of an electrostatic device control device according to another embodiment of the present invention. 8A and 8B are a top view and a front view of a photoconductor on which a latent image for measurement is formed according to the present invention, and FIG. 9 is a readout latent image signal voltage waveform diagram, and FIG.
11 is a command signal circuit diagram for instructing the operation of the apparatus shown in FIG. 1 and FIG. 7, respectively. FIG. 12 is a block diagram of a processing circuit for the read latent image signal.
FIG. 3 is a waveform diagram for explaining the operation of the processing circuit shown in FIG. 12. Here, 11 is a photoreceptor, 15 is a power source, 16 is a charger, 17 and 33 are static eliminators, 19 is a source, 22 is a lamp, 25 is a gate, 26 is an oscillator, 27 is a document table, 28, 32, 35 is a lamp, 38 is a resistor, 4
3 is a developing device, 44 is a transfer device, 46 is a squeezer, 47
is a servo motor, 70 and 71 are gate circuits, 7
5 and 76 are peak hold circuits, and 79 and 80 are comparators.

Claims (1)

[Claims] 1. After forming a charge image on an electrostatic latent image forming member,
In the recording device that visualizes the charge image, a first charge image in a bright area and a second charge image in a dark area are created by irradiating the electrostatic latent image forming member with light having a predetermined intensity. , obtain a first signal and a second signal corresponding to the first charge image and the second charge image, and set the charging conditions for the electrostatic latent image forming member using the second signal corresponding to the dark area. An image stabilizing device characterized in that it controls exposure conditions for forming a latent image or developing conditions for developing a latent image using the first signal corresponding to a bright area. 2. In claim 1, the first charge image consists of a bright charge image obtained by irradiating light of a constant intensity on an electrostatic latent image forming member, and the second charge image An image stabilizing device comprising a dark charge image obtained by not irradiating the image.