JPS592897B2 - Multi-process control device for electrostatic copying machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrostatic copying machine, and more particularly to an apparatus for controlling various processing stations provided within the electrostatic copying machine.

To explain the process of electrostatic copying, first a photoconductive surface is uniformly charged, then a light image of an original image is projected onto this charged surface, and an electrostatic latent image corresponding to the original image is formed on this photoconductive surface. be done.

Next, when toner particles are electrostatically attached to this electrostatic latent image, the latent image changes to a visible image. This toner image is then transferred onto a sheet-like image support, and the toner image on the image support is permanently fixed to the support to obtain a copy of the original image. Such a copying method is described in Carlson U.S. Patent No. 229,767.
It is stated in No. 1. In electrostatography, the electrical characteristics of the photoconductive surface at each processing station are subject to change and are difficult to adjust.

Furthermore, the electrical characteristics of the photoconductive surface must be repeated periodically, but since the electrical characteristics of the photoconductive surface change due to temperature changes, usage time, ie dark decay, etc., electrostatic copying machines It is difficult to continuously reproduce the potential of the photoconductive surface at each processing station, and for this reason, electrometers have been used to measure the electrical properties of the photoconductive surface. The use of electrometers in electrostatographic copiers is well known to those skilled in the art, the advantage of which is the ability to directly measure the amount of charge on a particular surface as it passes under the electrometer's probe. Therefore, if a probe is placed immediately after one of the processing stations, the signals sent from the probe can be used to control the processing station.
In the past, it was common practice to control only one electrostatic imaging station with one electrometer, but in order to control all processing stations, one probe was used immediately after each processing station. It is necessary to provide
The entire device becomes difficult to handle, and it is not suitable for installation in a commercially available copying machine. Various types of electrometer devices are known for measuring the electrical characteristics of a photoconductive surface. For example, U.S. Pat.
No. 6487, No. 3013203, No. 3068056, No. 3321307, No. 3406334, No. 343
US Pat.
In this issue, the average charge of the photoconductive layer during exposure is measured using an electrometer to automatically control the exposure equipment. In this copier, a sheet of paper coated with zinc oxide is sandwiched between a transparent conductive sheet and a grounded conductive plate, and this paper coated with zinc oxide acts as a photoconductive layer. I'm starting to do that. After the electrostatic latent image is formed on the photoconductive layer, the sheet is removed for development by conventional electrostatographic techniques. In this process, the above-mentioned clamping body is charged and then a light image of the original image is projected onto it. This support is... It operates as an electrometer with a high input impedance amplifier, producing an output signal proportional to the average charge on the zinc oxide paper. This signal controls the exposure time after passing through an amplifier combined with electrical circuitry. Therefore, in the above patent, a light image is projected onto the zinc oxide plate until the charge on the plate reaches a predetermined potential, and the projection time is also varied. The use of electrometers in electrostatographic copiers was developed in the commercial rather than research field, but development was hampered by the high cost, complexity, and instability of the equipment.

The above equipment uses tipper or vibration probes, expensive high voltage amplifiers and feeds. A back circuit is required. Other references to this electrometer device include U.S. Pat.
No. 370225 and No. 3449668, and these electrometer devices are used for various tests. ``Electrophotography'' by Mr. Shaffert and Mr. Dessauer.
The academic book ``Zerogly-1 and Related Processes'' co-authored by Messrs. R) and Clark specifically mentions electrometers. However, none of the above references describe a relatively simple, low cost, and accurate electrometer device that allows easy control of all of the various processing stations in an electrostatographic reproduction machine. Accordingly, it is a primary object of the present invention to improve the electrostatographic process by sequentially controlling each electrostatic imaging station using an electrometer device.

According to the present invention, an electrostatic copying machine is provided that includes a plurality of image processing stations. In this example, the copying machine includes a photoconductive member and means for simulating the photoconductive member;
The photoconductive member is adapted to pass through each processing station, and the simulating means is attached to and moves with the photoconductive member.

As the photoconductive member passes each processing station, simulating means generates an electrical signal representative of the instantaneous condition of the photoconductive member immediately after passing the processing station. The electrical characteristics of the processing station are thus easily controlled. Other objects and advantages of the present invention will become more apparent from the detailed description based on the accompanying drawings.

Although the present invention will now be described in the context of a color electrostatic copying machine, reference will always be made to the accompanying drawings for an understanding of the general principles of operation of the machine. The same numbers in the attached drawings represent the same parts. In the following description, the overall process of making a multicolor copy will first be described, and then the structure of the various subassemblies in the copier according to the invention will be explained in detail. Although the invention is particularly suitable for color electrostatographic reproduction machines, it will become clearer from the following description that it is not limited only to the embodiments described herein, but is also suitable for other electrostatic reproduction machines. As shown in FIG.
0 is rotatably attached to the photoconductive member, and the outer peripheral surface of the drum 10 is a photoconductive surface 12.

Suitable photoconductors are those described in US Pat. No. 3,655,377. Generally, an aluminum substrate coated with selenium is used for such photoconductive members. A series of imaging processing stations are provided around the circumference of the drum 10 such that as the drum 10 rotates in the direction indicated by arrow 14, the surface of the drum 10 passes through one processing station after another. There is. The present invention employs a closed loop system to control each processing station. The operation of each processing station is substantially optimized taking into account the properties of the photoconductive surface and the changes occurring therein during image processing, and a simulating means according to the invention is installed at a predetermined position along the length of the drum 10. That is, a probe 16 is provided. However, it will be readily apparent to those skilled in the art that the probe could be movably mounted on the drum to measure variations in electrical properties along the length of the drum. The probe 16 generates an electrical signal that simulates and is indicative of the properties of the photoconductive surface. The probe 16 according to the present invention will be described below as attached to a photoconductive member, but the present invention is not limited to this embodiment. For example, the probe 16 may not be attached to the photoconductive member but may be adjacent to the photoconductive member immediately after the processing station being controlled. The structural configuration of drum 10 and probe 16 will be discussed in detail in the discussion of FIGS. 2 and 3. A timing disk is attached to one end of the shaft of the drum 10, and this disk is designed to synchronize the rotation of the drum 10 and various operations in conjunction with the logic circuit of the copying machine. In this way, correct sequence control is performed at each processing station. First drum 1
As 0 rotates, the photoconductive surface passes through charging station A.

At charging station A, a corona generating device 18 traverses the photoconductive surface 12 in the longitudinal direction. Therefore, the photoconductive surface 12 can be charged substantially uniformly to a relatively high potential by the corona generating device 18. At this time, please be aware that the probe 16 will also be charged. Preferably, the corona generating device 18 is of the type described in U.S. Pat. and photoconductive surface 12
and a conductive shield body in close contact with the conductive shield body. This shield generally surrounds the corona electrode wire except for the opening where the charge is radiated. Preferably, the shield is mounted so as to attract excess radiation from the corona electrode wire. When a high voltage is applied to this corona electrode wire, corona is generated along the surface of the electrode wire, and ions adhere to the adjacent photoconductive surface 12 and probe 16. The structural configuration of this corona generating device 18 and its associated probe 16 will be explained in detail in the description of FIG. Returning again to FIG. 1, once photoconductive surface 12 and probe 16 are charged to a substantially uniform potential, drum 10 rotates and enters exposure station B. Referring again to FIG. In this exposure station B, a charged photoconductive surface 12 and a probe 1 are connected to each other.
An optical image of the original image 20 that has passed through the colored filter is projected onto the color filter 6 .

This exposure station B consists of a movable lens system 22, a color filter mechanism 24, and a scanning lamp 26. An original image 20, such as a sheet of paper, a book, or the like, is placed face down on a transparent platen 28. The lamp 26 moves in synchronization with the lens 22 and filter mechanism 24, and the platen 2
The light is scanned from one end of the original image 20 placed on the screen 6 to the other end. The movement operation at this time is to move the drum 10 indicated by the arrow 14.
Therefore, the optical image of the original image 20 is correctly projected onto the photoconductive surface 12 without deviation. At this time, a predetermined color filter is interposed in the optical path by the filter mechanism 24. This color filter is lens 2
2 forms an electrostatic latent image on photoconductive surface 12 and partially discharges probe 16. The electrostatic latent image formed on the photoconductive surface 12 corresponds to a predetermined region in the electromagnetic wave spectrum, and is hereinafter referred to as a monochromatic electrostatic latent image. A method of controlling the exposure apparatus will be described when explaining FIG. 6. A monochrome electrostatic latent image formed on photoconductive surface 12 by exposure and partially discharged probe 16 enters development station C.

This developing station C consists of three independent units 3
0, 32 and 34. All development units are preferably of the type known as magnetic brush development units. A typical magnetic brush device uses a magnetic developer consisting of carrier particles and toner particles, and the toner particles generally have heat-fusible properties. This developer stands upright continuously along the lines of magnetic force,
It becomes brush-like. When the electrostatic latent image on photoconductive surface 12 and the partially discharged probe 16 come into contact with a brush of developer material, toner particles in the developer are attracted to the latent image and probe 16. Each developing unit contains toner particles colored in a predetermined color. For example, an electrostatic latent image formed by a green filter is developed by attaching magenta toner that absorbs green, and an electrostatic latent image formed by blue and red filters is developed by yellow and cyan, respectively. toner particles are attached and developed. As toner particles decrease, more toner particles are added to this unit.
Each of these units is provided with a toner particle distributor for storing toner particles to be supplied, and the probe according to the present invention distributes one toner particle to each developer unit to maintain a substantially constant concentration of toner particles in the developer. used to maintain. This operation ensures that the quality of the copy remains good over a long period of time. The developing device in the copying machine and the relationship between this developing device and the probe 16 shown in FIG.
The toner dispensing device and the relationship between the toner dispensing device and the probe 16 will be described with reference to the figures and also with reference to FIG. Next, the drum 10 is transferred to the transfer station D.
At this station, the toner image electrostatically adhered to the photoconductive surface 12 and the probe 16 is transferred onto a final image support 36 in the form of a sheet.

The image support 36 is a conventional paper or thermoplastic sheet material. A bias voltage is applied to transfer roll 38, which causes image support 36 to circulate in the direction indicated by arrow 40. The transfer drum 38 is the drum 10
The drum 38 rotates in synchronization with the drum 10, that is, at the same speed as the drum 10, and a voltage is applied to the drum 38 from a variable power source. An image support member 36 is removably secured on a transfer drum 38 for movement into a recirculation path so that a series of toner images can be registered and superimposed on this support. Since the probe 16 is connected to a power source that applies a bias voltage to the transfer drum 38,
The magnitude of the bias voltage applied to is properly adjusted to optimize the transfer process. This feature of the invention will be discussed in detail later in the discussion of FIG. Before explaining the rest of the electrostatographic process, a brief mention of sheet feeding equipment is provided.

The image support 36 is fed from a stack 42 in a tray 44 by a feed roll 46, which cooperates with a brake roll 48, to separate and advance the topmost sheet of the stack 42 one after another. The uppermost sheet sent out in this way moves within the chute 50 and moves to the aligning roll 5.
It passes through the nip area between the two. The support is then removably secured by gripping fingers 54 mounted on the transfer roll 38 and moved through the recirculation path. When a plurality of toner images (three toner images in this example) are transferred onto the support 36, the grip fingers 54 release the support 36. The support 36 is then separated from the transfer roll 38 by a peeling bar 56, and the support 36 is separated from the transfer roll 38 by a peeling bar 56. The image is placed on the belt conveyor 58 and enters the fixing station F. At this fixing station F, the multilayered toner image is permanently fixed onto the image support by a fuser.

A suitable fuser is of the type described in US Pat. No. 3,498,592. After fixing the toner image, the support 36 is used for endless printing. belt. Since it is delivered to a tray 66 by the conveyor 62, the operator of the copying machine can take it out. The final image processing station in the direction of drum rotation indicated by arrow 14 is
It is designated as cleaning station E.

Although most of the toner particles on photoconductive surface 12 are transferred onto support 36, toner particles often remain on photoconductive surface 12 and probe 16 after transfer. The cleaning station E is intended to remove residual toner particles on the photoconductive surface 12 as the photoconductive surface 12 passes through the station E. The residual toner particles are first removed by a cleaning corona generating device (FIG. (not shown). Photoconductive surface 12 is then contacted by a rotatably mounted fiber brush 68 to remove toner particles on probe 16 and photoconductive surface 12. This brush type cleaning device is described in US Pat. No. 359
The one described in No. 0412 is suitable.

The above description should provide a thorough understanding of the general operating principle of an electrostatic copying machine using the apparatus according to the present invention. We now turn to the subject matter of the invention.

FIG. 2 shows drum 10 with probe 16 mounted thereon.
A portion of the probe 16 consists of a photoconductive layer or selenium layer and an aluminum substrate. The structural shape of this probe 16 will be described in detail when describing FIG. A small hole is passed through the circumferential surface of the drum 10, and a probe 16 is provided in the small hole. Further, the probe 16 may be installed by cutting a slot in the drum 10 so that it can slide on the drum 10, and may be provided at any position in the longitudinal direction of the drum, or may be fixed as shown in FIG. .
Similarly, the probe 16 may be moved within the reproduction machine to measure the charge distribution along the length of the mounted photoconductive surface 12. The shaft 70 of the drum 10 is
The hollow center is a tubular member through which wiring can be connected to an external probe and associated electrical circuit. This electric circuit will be explained in detail later in the explanation of FIG. 4. Sliding ring 72 is operative to conduct electrical signals from probe 16 to an electrical circuit as shown in FIG. The electrical circuitry described above processes the electrical signals from the probe 16 and converts them into control signals that are sent to the processing stations of Tanigana to adjust the individual stations. Next, referring to FIG. 3, this figure shows the probe 16 and the drum 10.
FIG. 7 is a partial cross-sectional view of a portion of the photoconductive surface 12, as shown in which a transparent, generally conductive sheet 73 is secured to the photoconductive surface 12. FIG.

A bore is formed in the photoconductive surface 12 and a conductive substrate 74 bonded thereto. This bore 76 corresponds to the transparent sheet 7
A tubular insulating member 78 through which a conductive member, ie, a wire 81 connected to the wire 81 is passed, is positioned. A transparent conductive sheet 73 is secured to the photoconductive surface by an insulating cement 80, and a wire 81 is secured to the transparent conductive sheet 73 by a conductive cement 82. Thus, the sum of the voltages across the two insulators, ie, the photoconductor 12 and the insulating layer, or cement 80, is continuously monitored. The only change in the characteristics of the photoconductor 12 is that caused by the voltage displayed by the sensor. Since the voltage across the insulating layer 80 is approximately constant, the voltage characteristics of the photoconductive surface can be readily determined by subtracting the constant voltage across the insulating layer using an electrical circuit. The probe according to the present invention is a photosensitive capacitive device having three thin films on an aluminum substrate, and is mounted flat on the surface of the photoconductor. The output of this device is a voltage that increases or decreases in value, measuring the condition of the photoconductive surface as it passes through each adjacent processing unit. The output of this probe is similar to the state when the photoconductive surface passes through the processing unit, and this signal is electronically processed and converted into a control signal that controls the desired state of the processing station. . A feedback circuit is provided to each processing station to control the electrical characteristics of the processing station in response to the measured characteristics of the photoconductive surface. The transparent conductive sheet 73 may be made of a conductive glass sold by Pittsburgh Plate Glass Co. under the trademark NESA, or a glass sold by Corning Glass Co. under the trademark Electroconductive. It may be manufactured by The conductive sheet 73 preferably has a thickness of about 25 microns or less, and the transparent adhesive dielectric 80 similarly preferably has a thickness of about 25 microns or less, with the photoconductive surface having a thickness of about 60 microns or less. It is preferable to make it thick. The tubular member 78 is provided with a flange 76a which allows the member to be properly positioned within the stoma or bore 76. The tubular member 78 is preferably constructed from a suitable insulating plastic such as Teflon.
Next, FIG. 4 will be explained.

The voltage signal from probe 16 is passed through one gain amplifier 84.
will be processed. If the amplifier has high impedance,
It can be used in combination with the probe according to the invention. The electrical output of amplifier 84 is further amplified by two stage amplifiers 86 and 88 and sent to a hold circuit consisting of a high impedance unit gain amplifier 90 and a capacitor 92. However, due to the normally open contact 94, the signal from the amplifier is not always applied to this hold circuit. The copier logic includes circuitry that operates to close contact 94 at predetermined times so that a sample voltage is applied across high impedance unitary gain amplifier 90. Closing of contact 94 results in two separate states. The first is that the voltage of the probe is applied to the high impedance amplifier 90, and the second is that the capacitor 92 in the hold circuit is charged with the same voltage as the probe. Once the curve has passed through each processing station, a signal is sent from the copier's logic circuitry to open contact 94. However, the probe voltage has been charged to capacitor 92, and the voltage across capacitor 92 continues to be applied to amplifier 90. The impedance of this amplifier is high so that the output is relatively constant until the next time contact 94 is closed and a new voltage is applied.
This output voltage remains approximately constant until the next sample signal is applied to each processing station. If the magnitude of the voltage of the next sample signal is different from the voltage of the first sample signal, capacitor 92 connects contact 94
and is recharged to this new voltage through the amplifier 88 circuit. Once capacitor 92 has recharged to this new voltage, the output voltage from amplifier 90 is applied to supply voltage operational amplifier 96, which holds the output voltage from the valley processing station at a substantially constant voltage until the next signal is sent. At the end of the sample period, contact 94 opens again and all circuits are ready for the next sample signal. This type of device therefore allows the probe according to the invention to detect increases and decreases in voltage and, at about the same time, generate continuous control signals for adjusting the voltage applied to the processing station. The circuit explained based on FIG. 4 is shown below with reference numeral 9.
8. Next, FIG. 5 will be explained. This figure shows the corona generator 18 and the circuitry that cooperates with it to adjust the charging voltage. The structure of the corona generator 18 consists of a conductive shield 100 constructed from aluminum or stainless steel and generally having an inverted U-shaped cross section. The corona generating device includes a corona electrode wire that acts as a discharge electrode and is made of a tungsten oxide coating on a non-corrosive material such as stainless steel, platinum or tungsten. preferable. The electrode wire 102 has an outer diameter of about 0.089 mm (0.0035 inches) and a substantially uniform thickness. This corona electrode wire 102 extends along the longitudinal direction of the shield body 100,
Both ends are connected to suitable insulator blocks. This insulation block is made of an insulator, and the end opposite to the end connected to the corona electrode wire is connected to the end of the shield 100. As previously mentioned, when probe 16 passes charging station A, it produces an electrical output signal. This signal is sent to circuit 98 and converted to an output signal that is processed by logic circuit 104. Preferably, logic circuit 104 includes a discrimination circuit for comparing output signals from circuit 98. This discrimination circuit can be a thyristor switch that is activated to turn on and remain in this state when the output signal becomes greater than a reference voltage. The state of the flip-flop circuit is changed by the signal from this discrimination circuit,
An output signal is generated from here. This output signal, after being amplified by a suitable amplifier, energizes the input controller.
The output signal from this input controller regulates the high voltage power supply 106. For example, the high voltage power supply 106 may be connected to the corona electrode wire 10
2 by applying a voltage of about 7000 volts to 400! It is preferable to use a constant current power supply that allows the current of TA to flow. Corona electrode wire 102 thus charges photoconductive surface 12 to a substantially uniform voltage of approximately 900 volts. Corona electrode wire 102
The output from the probe 16 is regulated by the electrical signal from the probe 16, so that the corona electrode wire 102 remains at the probe 1 regardless of changes in ambient conditions or chronological changes in the photoconductive surface.
6 to approximately 900 volts. Next, FIG. 6 will be explained.

In this figure, a probe 16 electrically interlocked with a scanning lamp is shown.
is shown. Once again, when probe 16 is partially discharged at exposure station B, electrical circuit 98 generates an output signal. This output signal is processed by logic circuit 108. This logic circuit 108 is preferably a discrimination circuit that compares the output signal sent from the circuit 98 with a reference value. This discrimination circuit can use a thyristor switch that remains on when an output signal greater than a reference level is input. The signal from the discrimination circuit changes the state of the flip-flop, from which an output signal is generated. The output signal from this flip-flop is an error voltage corresponding to the lamp voltage change required to discharge probe 16 to the desired level. This error signal is amplified with a suitable amplifier and sent to an input controller that regulates the voltage of the high voltage power supply 110 that energizes the scanning lamp 26. The intensity of the light beam emitted by lamp 26 is thus adjusted by the error signal. Preferably, lamp 26 is lit at a nominal value to provide the best exposure. When an error signal is generated, the voltage applied to the lamp varies around its nominal value to compensate for changes in photoconductor properties. Next, the developing device will be explained with reference to FIG.

When probe 16 is developed with toner particles, the output signal from circuit 98 changes again to represent the current state of the photoconductive surface. The output signal from this circuit 98 is processed by logic circuit 112. Each developing unit 3
0, 32 and 34 are magnetic developing rolls 115, 117 and 119 to which a bias voltage is applied as shown in FIG.
These rolls develop only electrostatic latent images on photoconductive surface 12 that are charged to a voltage greater than the bias voltage applied to the rolls. Circuit 98 processes electrical signals from probe 16 as it passes exposure station D. The output signal from circuit 98 is processed by logic circuit 112. This logic circuit 112 is preferably a discrimination circuit that compares the output signal from the circuit 98 with a reference value, and when an output signal larger than this reference value is input to this discrimination circuit, the logic circuit 112 turns on. A thyristor switch can be used to continue the operation. , the signal from this discriminator circuit changes the state of the flip-flop and generates an output signal therefrom. The output signal from a given developer unit operates an AND gate and is then amplified by a suitable amplifier to energize the input controller. This input controller includes the developing rollers 115 and 117.
and the high voltage power supply that energizes 119. The logic circuit 112 has three channels, one for each of the developing units 30, 32 and 34. The copier logic generates another signal to the AND gate to activate the channel corresponding to the developer unit being energized. It will be clear to those skilled in the art that if only one developer unit is used in a monochromatic copying machine, then only one channel is required. A developing device using multiple developing units is disclosed in U.S. Patent Application No. 255
No. 259 is described, and its content is related to the present application. The power supply 114 connects the developing rolls 115 and 11.
7 and 119 to a voltage of approximately 500 volts. Next, FIG. 8 will be explained.

This figure shows the probe 16 interlocking with the transfer drum 38. This transfer drum 38 is connected to the aluminum tube 11
It is preferable to apply urethane 118 of approximately 63 mm (% inch) thickness to the circumferential surface. It is also preferred to spray polyurethane 120 to a thickness of about 1 mil over the cast urethane 118 layer. The hardness of the transfer drum 38 is preferably about 10 to 30 on the shore-τ A scale, and the low resistivity is preferably about 108 to about 1011 ohm-cm. Power supply 122; applies a DC voltage O to aluminum tube 116 by means such as a carbon brush and brass ring assembly (not shown). This bias voltage can vary between about 1500 volts and about 4500 volts;
The correct adjustment is made in response to the signal generated by the probe 16. The force applied at the point of contact between photoconductive surface 12 of drum 10 and transfer drum 38 with intervening support 36 is approximately 453 y at most.
(1 pound) or less.
The main synchronous drive motor rotates the transfer drum 38, and this drive is coupled directly to the transfer drum 38 by a flexible metal bellows that raises and lowers the transfer drum 38.
Synchronization of transfer drum 38 and drum 10 is accomplished by precision gearing that connects the main drive motor to transfer drum 38 and drum 10. After transferring the toner image, circuit 98
processes the signal from probe 16. This processed signal is sent to logic circuit 124. This logic circuit 124 is preferably a discrimination circuit that compares the output signal sent from the circuit 98 with a reference value, and this discrimination circuit includes:
A thyristor switch can be used that turns on when an input signal greater than a reference value is applied. The signal from this discrimination circuit changes the state of the flip-flop and generates an output signal therefrom. This output signal, after being amplified with a suitable amplifier, is applied to an input controller that adjusts the power supply 122 applying a bias voltage to the transfer roll 38. Therefore, the bias voltage of the transfer roll 38 is
Since it depends on the state of the probe 16, the transfer state can be almost the best. This means that probe 16
This is possible by detecting the state of This method is a closed-loop and automatic correction method because the bias voltage changes on the next transfer and corrects for the errors displayed in the previous cycle. Next, FIG. 9 will be explained.

This figure shows a structure for controlling the distribution of toner particles to each developer unit. developing unit 30,
32, 34 are toner particle storage containers 126, 128,
130, and each toner particle storage container contains predetermined colored toner particles. All of the above containers are the same, so only one will be explained below. Therefore, in this example, the toner particle storage container 12
Touch 6. The toner particle storage container 126 is a tubular cylinder 132 closed at both ends, and a screen 134 is provided at the bottom of the tubular cylinder 132.
Toner particles 136 are stored within the tubular member 132;
Toner particle storage container 126 rotates about a longitudinal axis. Vibrating motor 138 rotates the toner particle housing about its longitudinal axis, so that the toner particles are delivered in portions into the developer material in developer unit 30. The signal from probe 16 is passed through a commutator to circuit 98, which generates an output signal that is processed by logic circuit 140. Logic circuit 140 serves as a discrimination circuit that compares the output signal from circuit 98 with a reference value. This discrimination circuit can use a thyristor switch that operates to remain on when an electrical signal larger than a reference value is input. The signal from the discrimination circuit changes the state of the flip-flop and produces an output signal from the flip-flop. The output signal from a given development unit operates on an AND gate;
The AND gate sends a control signal to the vibration motor 138 of the toner particle container associated with this developer unit. This control signal simultaneously resets the flip-flop so that the output signal from probe 16 determines the concentration of toner particles in the developer material. Since the amount of charge on the probe 16 varies depending on the charge remaining on it after exposure and the charge possessed by the toner particles, the output signal of the probe 16 depends on the concentration of toner particles on the probe 16. It's going to change. The output signal from probe 16 is processed by the electrical circuitry previously described and converted into a signal that activates a vibration motor that rotates one of the toner particle containers about a longitudinal axis. As a result, a predetermined amount of toner particles are dispersed into the developer, and the concentration of toner particles in the developer is maintained substantially constant. In this way, the quality of the copy is maintained at the desired level. To summarize the foregoing description, in an electrostatic copying machine according to the present invention, a simulating means is mounted on a photoconductive member and is adapted to simultaneously pass through a processing station through which the photoconductive member passes. The simulating means is also operative to simulate the photoconductive member and to generate an electrical signal representative of the condition of the photoconductive member. This electrical signal is thus representative of the condition of the photoconductive surface as it passes through each processing station and is used to adjust each processing station. In fact, this operation allows complete control of each processing station within the electrostatic copying machine and substantially optimizes the various parameters within the machine that are related to the quality of the copies. Accordingly, the present invention provides an apparatus for simulating a photoconductive surface and generating an output signal representative of the condition of the photoconductive surface at a processing station. The signals at each processing station are sent to a closed loop control system and utilized to adjust the various processing stations within the copier. Although the present invention has been described above based on the embodiments shown in the attached drawings, the present invention is not limited to these embodiments in any way, and various design changes can be made within the scope of the attached claims. It is.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of a color electrostatic copying machine according to the present invention. FIG. 2 is a schematic perspective view of a photoconductive drum used in the copying machine shown in FIG. 1 and equipped with a probe according to the invention. FIG. 3 is a partial cross-sectional view of a probe used to simulate a photoconductive member. Figure 4 is a block diagram of a circuit that periodically samples the electrical signals sent from the probe. Figure 5 is a block diagram of the circuit that controls the corona generator. FIG. 6 is a block diagram of a circuit that adjusts the intensity of the light beam that exposes the photoconductor drum during charging. FIG. 7 is a block diagram of a circuit for adjusting the bias voltage of the developing device. FIG. 8 is a block diagram of a circuit for adjusting the bias voltage of the transfer drum. FIG. 9 is a block diagram of a circuit for controlling delivery of toner particles to the developer used in the developing device shown in FIG. 10...Photoconductive drum, 16...Simulating means.

Claims (1)

[Scope of Claims] 1. A photoconductive member movably mounted within an electrostatic copying machine and adapted to pass through each processing station;
means mounted on the photoconductive member for simulating the photoconductive member and generating electrical signals representative of the momentary state of the photoconductive member; and means for mounting the simulating means on the photoconductive member. Consisting of a small hole provided,
An electrostatographic copier with multiple processing stations. 2. The method of claim 1 further comprising means electrically connected to the simulating means and each processing station for generating an electrical control signal operative to adjust the electrical output from each processing station. Copy machine. 3 means for generating a reference signal representative of a desired moment-to-moment state of the photoconductive member; comparison means for comparing the electrical signal with the reference signal and generating an error signal corresponding to the difference between the two; and said error signal. 3. The reproduction apparatus of claim 2, further comprising means for controlling one of the processing stations in response to. 4. A processing station includes means for charging the photoconductive member and the simulating means to a substantially uniform potential, and exposing the charged photoconductive member and the simulating means to an optical image to form an electrostatic latent image on the photoconductive member. means for forming and partially discharging said simulating means; means for generating a reference signal representative of a desired potential on said photoconductive member after exposure of a light image; and an electrical signal from said simulating means and a reference signal. a comparison means for generating an error signal by comparing the
2. A copying machine according to claim 1, further comprising means for controlling said exposure means in response to said error signal. 5. A processing station comprising: means for charging the photoconductive member and the simulating means to a substantially uniform potential; exposing the charged photoconductive member to a light image to form an electrostatic latent image thereon; means for partially discharging the means; means for developing the electrostatic latent image and the partially discharged simulating means with toner particles; means for applying a bias voltage to the developing means; 2. A copying machine according to claim 1, further comprising means for controlling said bias voltage applying means, which is connected to said bias voltage applying means.