JPH0315182B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an electrostatic recording device.

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

Therefore, even when the electrostatic latent image toner is used to visualize the image, the resulting image is unstable.

In order to eliminate such defects, the latent image or visible image is measured, and based on the measurement results, temporary charging,
It is sufficient to control exposure, development bias, etc. As mentioned above, the control cycle may be performed all the time, but if it is attempted to be performed all the time, the area where the image for measurement is to be formed will be generated in the area of the member where the electrostatic latent image is formed, other than the area where the electrostatic latent image is created. Therefore, even the member on which the electrostatic latent image is formed must be changed for the control cycle, and the apparatus becomes larger. Furthermore, even when there is no need to perform a control cycle, time is wasted and the time required for image formation becomes longer.

The present invention aims to eliminate the above-mentioned drawbacks.

That is, the present invention provides an electrostatic recording device in which an electrostatic latent image for recording is formed on a member on which an electrostatic latent image is formed by a latent image forming means, and the electrostatic latent image for recording is developed by a developing means. A process cycle in which the developed image is transferred to a transfer material, and a light image for measurement, which is different from that for recording, is irradiated for a certain period of time in the electrostatic formation area that contributes to the transfer of the electrostatic latent image forming member. Measuring the surface potential of a measurement image formed on a member on which an electrostatic latent image is formed, controlling the latent image forming means based on the measurement result, and having a measurement cycle independent of the process cycle,
A first step of executing the process cycle after executing the measurement cycle by applying a recording start command.
mode, and a second mode in which the process cycle is executed without executing the measurement cycle upon application of a recording start command, for a predetermined period of time after the previous recording start command to execute the first mode was applied. a second period until the number of applications of the recording start command reaches a predetermined number after the application of the recording start command to execute the first mode described above reaches a predetermined number of times, and the first period elapses. In either one of the third period until the number of applications of the subsequent recording start command reaches a predetermined number, or the fourth period which is the longer of the first period and the second period, control means for executing the second mode when the recording start command is applied, and executing the first mode when the next recording start command is applied after any one of the periods has elapsed; Furthermore, the control means provides an electrostatic recording device that inhibits transfer to the transfer material during execution of the measurement cycle.

Thereby, a measurement cycle can be performed as necessary, so that an increase in the time required for image formation can be prevented as much as possible, and a good image can be formed.

In addition, since the latent image for measurement can be created in the same area as the electrostatic latent image for recording, it is possible to create a latent image for measurement in the same area as for creating an electrostatic latent image for recording. This can prevent the device from becoming larger.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

First, the formation of a latent image for measurement in an electrostatic copying apparatus and the reading of the latent image for measurement will be described in detail with reference to FIGS. 1 to 6.

FIG. 1A is a side view showing the main parts of an electrostatic copying apparatus. When the photoconductive layer 13 is of N type, the photosensitive drum 11 is charged positively, and when it is of P type, the photosensitive drum 11 is charged negatively.

Incidentally, FIGS. 2A and 2B show the cross section of the photosensitive drum and its equivalent circuit, and the insulating layer 12 has a resistor R.
The photoconductive layer 13 can be replaced with a parallel circuit of a resistor R13, a capacitor C13, and a diode D13 (when no light is irradiated).

Therefore, if the DC voltage obtained from the DC power source 15 is applied to the corona charger 16 via the switch SW1, the photoreceptor 11 will be charged at the end of the primary charging.
There are charges on the top 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 to 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 source 18 to the corona static eliminator 17 via the switch SW2, and at the same time, light 20 obtained from the light source 19 is irradiated via the half mirror 21. (The state at this time is shown in FIG. 8A) The light source 19 has a lamp 22 and an optical system 23 that forms the light from the lamp 22 into a slit shape. The lamp 22 is driven by applying current from the power source 24 to the gate 25.

The gout 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, and for example,
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%, a striped pattern will be formed on the photoreceptor 11 over the area D as shown in FIG. 8B (the shaded area is the area irradiated with the light 20). Simultaneous exposure will be performed. 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 charge removal and light irradiation as described above, the charge in the light irradiated portion disappears, and the charge remains in the light irradiated portion, 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 also 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, the electric charge of the insulating layer 12 in the area that is not exposed to the light is stored, 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 is improved.

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

Reference numeral 33 designates a corona static eliminator having the same configuration as that shown at 17, which 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
By removing the static electricity from the electrostatic latent image formed on the photoreceptor 11 in step 2), the current caused by the discharge of the latent image charge is led out to the terminal 39 as a potential between the resistor 38 connected between the conductive substrate 14 and the ground. This is to read out the electrostatic latent image.

A static eliminating voltage is applied to the static eliminator 33 from the DC power source 34 via the switch SW4, and the lamp 3
5, a current from a DC power source 37 is applied via a switch SW5.

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 SW4 and SW5 are turned on at the same time as this turning on or a short time in advance.
1. Turn off SW2 and SW3, and switch SW
6 is turned OFF to stop applying the oscillation output of the oscillator 26, and the gate 25 is closed and the lamp 22 is turned OFF.
stops emitting light.

The time t1 is set to a time necessary to form at least one cycle of a striped latent image on the photoreceptor 11 rotating at a constant speed in the direction of arrow S. When the striped latent image formed thereon arrives at a position corresponding to the static eliminator 33, static elimination and light irradiation are performed at the same time, so the charge on the photoreceptor 11 is discharged, and this discharge current flows through the resistor 38. flows.

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

Note that V1 is the charge image formed in the area irradiated with the light 20 (theoretically it should be OV, but
Actually, charges remain in the area irradiated with the light 20 in this way, so such area is called a 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).

The above cycle is a measurement cycle, and in this way, the controlled member can be controlled while executing the measurement cycle.

That is, 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 (the aperture 46 inserted in a part of the optical path of the reflected light 29) The most preferable electrostatic latent image can be formed on the photoreceptor 11 by controlling the servo motor 47.

After the control cycle as described above is completed,
This is a switch that enters the normal copying process (process cycle), turns on switches SW1, SW2, and SW3 again, turns off SW4 and SW5, and also controls the lamp 28 that illuminates the document table 27.
SW7 is turned on and current from the power source 41 is applied to the lamp 28 to turn it on. After that, the area on the photoreceptor 11 is charged by the charger 16 (this area has already been charged in the most preferable manner).
When the document platen drive motor M reaches at least a position facing the static eliminator 17, switch SW11
By moving the original platen 27 on which the original is placed in the direction of arrow M, the light 29 reflected by the original (of course it may be transmitted) is reflected by the mirror 42, and the light 29 that has already been properly The slit light SL shown in FIG. 8A is irradiated onto the charge removal position by passing through the aperture 46 and the half mirror, which are controlled to pass the amount of light. After being visualized with toner in step 43, the toner image is transferred onto a transfer paper (not shown) by a transfer device 44, and residual toner on the photoreceptor is removed by a cleaning blade, in preparation for re-formation of a latent image on the photoreceptor 11. It is.

Control of each switch as described above (in other words, execution of two cycles) can be realized, for example, by a circuit as shown in FIG.

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 a copy signal (recording start command) derived by operating the copy command button, and a higher level signal than the clock circuit 50 (other clock circuits 51 to 53 derives a low level signal).

Therefore, switches SW1, SW2, SW3, and SW6 are ON for time T1 after the application of the copy signal.
The other switches are turned OFF. however,
If necessary, switches SW4 and SW5 may be left ON.

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

The fall of the output signal of the clock circuit 50 drives the clock circuit 51, and a high level signal (other signal lines L1, L3, L
4 is 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 as long as it is enough 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.

A cycle caused by driving the timer circuits 50 and 51 is a measurement cycle.

Due to the fall of the output signal of the clock circuit 51,
The clock circuit 52 is driven, and a high level signal (other signal lines L1, L2,
L4 derives 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 this time T3 is a part of the normal copying process and is the time for primary charging to form an information latent image, the period T3 is a period of time until the area of the photoreceptor 11 that was facing the charger 16 faces the static eliminator 17. It is good if the time is longer than the time required for this.

Due to the fall of the output signal of the clock circuit 52,
The clock circuit 53 is driven and outputs a high level signal to the signal line L4 (the other signal lines L1 to L3 are low level signals) for a period of time T4.

Therefore, during T4 time, switches SW1 to SW3 and SW7, SW11 are ON, and switches SW4, SW11 are ON.
SW5 and SW6 are turned OFF.

Since this time T4 is the remaining portion of the time T3 in the normal copying process, the document table 27
The reflected light from the photoreceptor 1 is reflected from
It is sufficient as long as the time is sufficient for development and transfer of the irradiation to 1.

Therefore, the cycle caused by the driving of the clock circuits 52 and 53 is a process cycle.

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

In this case, the static eliminator 17 and lamp 32 are not required to form the electrostatic latent image shown in FIG. 1A.
In addition, since the lamp 35 for eliminating static electricity is unnecessary, a circuit as shown in FIG. 1B may be used instead of the circuit shown in FIG. 1A.
The structure is extremely simple compared to the case of using a photoreceptor having a three-layer structure as shown in FIG.

Such a two-layer control circuit 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 shows the first
Components labeled with the same numbers as in FIG. 1A are constructed of the same components as in FIG. 1A, and perform the same functions.

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

In other words, when switch SW8 is turned on, gate 2
The current of the power supply 24 is applied to the lamp 2 regardless of the operation of the lamp 5.
2, so the switch SW
8, the photoreceptor is always irradiated with slit-shaped light SL as shown in FIG. 8A.

Also, the switches SW9 and SW10 are the developer unit 43,
This is a switch for stopping the function of the transfer device 44. When the switch is turned ON, the developing device and the transfer device perform their original functions, and when turned OFF, the 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 timer circuit 61 is activated and a high level signal is derived to the signal line l1 over time t1, switches SW1 to SW3 and SW6 are turned on, and the switch
SW7 to SW11 are turned OFF.

This time t1 is the time to form a striped latent image for measurement, so after the position on the photoreceptor 11 facing the charger 16 passes the position facing the lamp 32, the position ( It is sufficient if the time is sufficient for the process to proceed until at least one set of bright charge images and dark charge images are formed.

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 the time period t2, the switches SW2,
Only SW8 is ON, other switch SWs are OFF
becomes.

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. The driving period of the clock circuits 61 and 62 is a measurement cycle. The fall of the output signal of the clock circuit 62 drives the clock circuit 63, and a high level signal is output only to the signal line 13 over time t3.

Therefore, during the time period t3, the switch SW1~
SW3, SW7, SW9, SW10 are turned on,
The other switches are set to OFF.

This time t3 is the time for performing primary charging in a normal copying process, 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 switches SW6,
SW8 turns OFF, other switches turn ON,
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.

Since this is the remaining portion of the time t3 in the normal copying process, the reflected light from the document table 27 is irradiated onto the photoreceptor 11 in the width of the area D (FIG. 8A).
Any time is sufficient as long as it is sufficient for development and transfer.

With the above configuration, it is possible to read out the bright area charge and the dark area charge as a voltage signal, but this voltage can be applied to a circuit as shown in Fig. 12 to control the primary charging and the amount of exposure. It is.

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.

Such a signal is 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. C 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 align the phases.

Since the gate circuits 70 and 71 respectively derive the signals applied to the inputs to the output lines 73 and 74 when a high-level gate signal is applied, the signals obtained on the output lines 73 and 74 are as follows. The results are as shown in FIGS. 13D and E, respectively.

Therefore, such signals are transferred to peak hold circuits 75, 7.
6 and hold it, output lines 77 and 78
It is possible to obtain level signals of V2 and V1, 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 output to output lines 83 and 84.

The signal obtained on the output line 83 is used as a signal to control the power supply 15, and the signal obtained on the output line 84 is used to control the servo motor 47 to control the aperture 4.
6, 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 84-7, 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 in accordance with the selected output line, the primary charging and exposure amount can be automatically controlled.

The clock circuit 52 and the clock circuit 63 are further provided with other input terminals 55 and 65, and these terminals are required to execute a measurement cycle when a recording start command is issued by operating the copy button. If there is no recording start command, it is possible to apply this recording start command as a trigger signal to the terminal 55 or 65 to omit the measurement cycle and directly start execution of the process cycle.

In a normal electrostatic copying machine, once the control cycle is executed to control the latent image forming means and the developing means, there is no need to execute the control cycle for a while (if the usage pattern or environment suddenly changes). In such a case, only the process cycle may be executed continuously for a predetermined period as described above.

FIG. 14 shows a circuit that executes a measurement cycle every predetermined time (for example, 30 minutes), and 90 is a command signal generator that commands the copier to start copying. The signal generated by the signal generator is applied to a waveform shaping circuit 91 and shaped into a pulse signal (command pulse). The command pulse (FIG. 15A) is applied to the timer circuit 92 as a trigger signal to instruct the timer circuit 92 to start operating, and is also applied to the AND gate 94.

The timer circuit 92 changes to a high level by the first command pulse P1 as shown in FIG. 15B,
This state is maintained until a predetermined time T1 has elapsed (the clocked time is not affected by the command pulse applied during this T1 period), and after the elapse of time T1 it changes to a low level and the command Timing starts again by applying pulse P6.

Reference numeral 93 indicates a one-shot multi which is triggered by the rise of the output of the timer circuit 92 and generates a pulse (FIG. 15C) wider than the command pulse P, and this output is led out to a terminal 95. . On the other hand, since the command pulse P and the output of the one-shot multi 93 are applied to the AND gate 94, a pulse signal as shown in FIG. 15D is obtained at the output terminal 96.

Therefore, the terminal 95 is replaced with the terminal 5 in FIG.
4 or to terminal 60 in FIG. 11, and if terminal 96 is connected to terminal 55 in FIG. 10 or terminal 65 in FIG. After that, during the predetermined time T1, when a command pulse is applied, only a process cycle is executed without executing a measurement cycle, and when the first command pulse is applied after a predetermined time period, the measurement cycle and process cycle are restarted. It is intended to carry out the following.

FIG. 16 shows still another embodiment,
Here, we measure the number of times the command pulse is applied,
When this number of times reaches a predetermined number, a measurement cycle is executed in addition to a process cycle by applying a command pulse.

That is, the command pulse (FIG. 17A) obtained from the waveform shaping circuit 91 is applied to the counter 97, and
This is applied to AND gates 99 and 98.

As shown in FIG. 17B, this counter 98 derives a low level signal until a predetermined number (N) of command pulses are applied (N=7 in FIG. 16).
After counting a predetermined number of command pulses, the ring counter derives a high level signal and returns to the initial state upon application of the next command pulse P8.

Therefore, when the command pulse P1 is applied in the initial state of the counter (output is at a low level), the counter starts operating, and until the counted value reaches N=7, the output terminal 101 of the AND gate 99 as shown in FIG. When the count value reaches N, an output as shown in FIG. 17C is obtained from the output terminal 100 of the AND gate 98.

Therefore, if the terminal 101 is connected to the terminal 55 or 65 and the terminal 100 is connected to the terminal 54 or 60, after applying the command pulse and executing the measurement cycle and the process cycle, the predetermined number of times (N
times) While the command pulse is applied, the measurement cycle is not executed even if the command pulse is applied, only the process cycle is executed, and after counting the predetermined number of times, the measurement cycle and the process cycle are restarted by applying the first command pulse. It executes the process cycle.

FIG. 18 shows still another embodiment,
Here, a measurement cycle is executed each time a command pulse is applied a predetermined number of times after a predetermined time has elapsed.

The command pulse obtained by the waveform shaping circuit 91 is applied to the timer circuit 102;
2, time measurement starts when a command pulse is applied in the initial state, and after a predetermined time T1 has elapsed, the output becomes high level, and this high level state is maintained until a reset signal is applied. This returns to the initial state again, and the output becomes low level.

Therefore, from the AND gate 103 to which the command pulse and the output of the timer circuit 102 are applied, the predetermined time T
No output signal is obtained until 1 has elapsed. Reference numeral 104 indicates a counter that counts a predetermined number N. In the initial state, the counter 104 starts counting only when a command pulse is applied, and after counting the predetermined number N, its output becomes a high level. This high level state is maintained until a reset signal is applied, and the application of the reset signal returns to the initial state again and the output becomes low level.

Therefore, from the AND gate 106, the predetermined time T
1 has elapsed and the command pulse has been applied a predetermined number of times, an output is obtained for the first time, and an output is obtained from the AND gate 107 at a time other than when an output is obtained from the AND gate 106.

The output of the AND gate 106 is sent to the delay circuit 10.
8 (the delay time is at least the pulse width of the command pulse) and is applied to the timer circuit 102 and counter 104 as a reset signal.

When one command pulse is obtained from the AND gate 106 by such a reset circuit, the timer circuit 102 and counter 104 are set to the reset initial state.

Therefore, in the circuit shown in FIG.
09 to the terminal 54 or 60, and connect the terminal 11 to the terminal 54 or 60.
0 is connected to the terminal 55 or 65, after the command pulse is applied and the measurement cycle and the process cycle are executed, the constant time T1 is counted and in addition, the number of times N is counted. Even if a command pulse is applied, only the process cycle is executed, and after the predetermined time T1 has been counted, the measurement cycle and the process cycle are executed by applying the first command pulse after counting the number of times N. .

FIG. 19 shows still another embodiment,
Here, a measurement cycle is executed every time a predetermined time T1 or more has elapsed since the command pulse P1 was applied and a predetermined number N or more of command pulses have been applied since the command pulse P1 was applied.

The command pulse obtained by the waveform shaping circuit 91 is applied to a timer circuit 111 having the same configuration as the timer circuit 102 and a counter 113 having the same configuration as the counter 104.

Therefore, from the AND gate 112, the predetermined time T
A command pulse, which is an output, is obtained only after 1 has elapsed, and an output is obtained from the AND gate 114 only after a predetermined number of command pulses have been counted.

AND gate 115, to which the outputs of AND gates 112 and 114 are applied, outputs AND gate 1.
An output is obtained only when outputs are derived from both 12 and 114, and an output is obtained from AND gate 116 when no output is obtained from AND gate 115.

The output of the AND gate 115 is sent to the timer circuit 11 as a reset signal via a delay circuit 117 having the same configuration as the delay circuit 108.
1 is applied to the counter 113.

Therefore, by connecting the terminal 119 to the terminal 54 or 60 and connecting the terminal 118 to the terminal 55 or 65, after applying the command pulse and executing the measurement cycle and the process cycle, the fixed time T1 and the Before both counts N are achieved, only the process cycle is executed without executing the predetermined cycle even if a command pulse is applied, and after the certain time T1 has elapsed and the count N has been counted. By applying the first command pulse, the measurement cycle and process cycle are executed again. In addition, in Figures 14, 16, 18, and 19,
Parts with the same number are composed of the same parts,
They have the same function.

In FIGS. 14, 16, 18, and 19, the timer circuit and the counter have been described as measuring a predetermined time T1 and a number N, respectively, but the time T1 or the number N may be changed depending on, for example, temperature changes. Of course, you can do it like this.

Furthermore, although the measurement cycle has been described as being executed before the process cycle, such a measurement cycle may also be executed after the process cycle.
If such a measurement cycle is performed during the pre-rotation of the photoreceptor, which precedes the process cycle, or during the post-rotation, which follows the process cycle, it is necessary to provide a separate time for the measurement cycle. It's nothing.

As explained above, according to the present invention, since a measurement cycle is executed as necessary before a process cycle, it is possible to prevent an increase in the time required for image formation as much as possible, and Good images can be formed.

In addition, since the latent image for measurement can be created in the same area as the electrostatic latent image for recording, it is possible to create a latent image for measurement in the same area as for creating an electrostatic latent image for recording. This can prevent the device from becoming larger.

[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 essential parts of an electrostatic device control device according to another embodiment of the present invention. 8A and B are a top view and a front view of a photoreceptor on which a latent image for measurement is formed according to the present invention, and FIG.
The figure is a readout latent image signal voltage waveform diagram, Fig. 10,
11 is a command signal circuit diagram for instructing the operation of the devices shown in FIG. 1 and FIG. 7, respectively. FIG. 12 is a block diagram of a processing circuit for a read latent image signal. FIG. 3 is a waveform diagram for explaining the operation of the illustrated processing circuit. Figure 14 is a block diagram of a selection circuit that determines whether to select a process cycle or measure a measurement cycle, Figure 15 is a waveform diagram to explain the operation of the selection circuit in Figure 14, and Figure 16 is a process cycle diagram. A block diagram of another embodiment of a selection circuit for determining whether to select or measure a measurement cycle, FIG. 17 is a waveform diagram for explaining the operation of the selection circuit in FIG. 16, and FIGS. 18 and 19. 2 is a block diagram of another embodiment of a selection circuit for determining whether to select a process cycle or measure a measurement cycle; FIG. Here, 11 is a photoreceptor, 15 is a power source, 16 is a charger, 17 and 33 are static eliminators, 19 is a light 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,
43 is a developing device, 44 is a transfer device, 46 is an aperture, 47
is a servo motor, 70 and 71 are gate circuits, 7
5, 76 are peak hold circuits, 79, 80 are comparators, 90 is a command signal generator, 91 is a waveform shaping circuit, 92, 102, 111 are timer circuits, 93
is one shot multi, 97, 104, 113 is counter, 94, 98, 99, 106, 107,
112, 114, 115, and 116 are AND gates.

Claims (1)

[Scope of Claims] 1. In an electrostatic device for recording, an electrostatic latent image for recording is formed on a member on which an electrostatic latent image is formed by a latent image forming means, and the electrostatic latent image for recording is formed by a developing means. A process cycle in which the developed image is visualized and transferred to a transfer material, and a light image for measurement different from that for recording is irradiated for a predetermined period of time in the latent image forming area that contributes to the transfer of the electrostatic latent image formed member. measuring the surface potential of a measurement image formed on the electrostatic latent image forming member, controlling the latent image forming means based on the measurement result, having a measurement cycle independent of the process cycle, and starting recording. A first mode in which the process cycle is executed after the measurement cycle is executed by application of a command, and a second mode in which the process cycle is executed without executing the measurement cycle by application of a recording start command. However, during a first period until a predetermined time has elapsed since the previous recording start command to execute the first mode was applied, the recording start command after the previous recording start command to execute the first mode was applied. a second period until the number of applications of the recording start command reaches a predetermined number, a third period after the first period until the number of applications of the recording start command reaches a predetermined number, or the first period and the second period.
If the recording start command is applied during any one of the fourth periods, which is the longer period of the periods, the second mode is executed, and after one of these periods has elapsed, the next mode is executed. The recording apparatus further comprises a control means for executing the first mode when a recording start command is applied, and further, the control means prohibits transfer to the transfer material during execution of the measurement cycle. electrostatic device.