JPS592898B2 - Detection device that simulates photoconductive members used in 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 electrostatic copying, the optical and electrical characteristics of the conductive 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 electrostatic copiers is well known to those skilled in the art, and its advantage lies in the ability to directly measure the amount of charge on a particular surface as it passes under the electrometer probe. be. Therefore, by placing a probe immediately after one of the processing stations, the signals sent from the probe can be used to control the processing station.

Up until now, it has been common practice to use one electrometer to support only one electrostatic imaging station, but is it possible to support all processing stations? In order to do this, one probe must be placed immediately after each processing station.
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, US Pat. No. 2,781,705, US Pat.
No. 1, No. 2956487, No. 3013203, No. 3
No. 068056, No. 3321307, No. 340633
No. 4, No. 3438705, No. 3611982, No. 3
No. 654893, No. 3674353, No. 374948
No. 8 describes the advantages of using an electrometer to measure the charge of a photoconductor, and in particular, the last U.S. Pat. Measurements are taken 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 Sanderch structure is charged and then projected with a light image of the original image. The Sandersch structure, along with a high input impedance amplifier, operates as an electrometer and produces 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 devices require chopper or vibrating probes, expensive high voltage amplifiers, and feed back circuits. 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 Dessdue
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 principal object of the present invention to improve electrostatography by using an electrometer device to sequentially mount each electrostatic imaging station.

According to the present invention, an electrostatic copying machine is provided that includes a plurality of image processing stations. In one example of the invention, a copying machine includes:
a photoconductive member and a detection device for simulating the electrical state, e.g., charge, of the photoconductive member; the photoconductive member is adapted to pass through each processing station; the detection device is attached to the photoconductive member; The lever moves together with the photoconductive member.

As the photoconductive member passes each processing station, a detection device generates an electrical signal representative of the instantaneous condition of the photoconductive member just after passing the processing station. In this way, the electrical characteristics of the processing station can be easily compromised. 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. 1, this electrostatic copying machine uses a photoconductive member in the shape of a drum 10 rotatably mounted within the frame (not shown) of the copying machine, and the outer peripheral surface of the drum 10 is , a photoconductive surface 12.

Suitable photoconductive members include 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. . The present invention employs a closed loop system to control each processing station. The operation of each processing station is approximately optimal, taking into account the properties of the photoconductive surface and the changes occurring therein during image processing, with a probe 16 according to the invention at a predetermined position along the length of the drum 10. is provided, which constitutes a detection device. 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. Probe 1 according to the present invention
6 will be described below as being 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, as drum 10 rotates, the photoconductive surface passes 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 note that the probe 16 is similarly charged. Corona generating device 18 is preferably of the type described in U.S. Pat. No. 2,836,725;
This type of corona generator consists of a corona electrode wire connected to a high-voltage power source, a photoconductive surface accommodating the corona electrode wire, and a photoconductive surface
2 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. This shield body is
Preferably, it is mounted 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 detailed structure of this corona generating device 18 and the relationship between it and the probe 16 will be explained in detail when referring to FIG. 5. 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 scans the light from one end of the original image 20 placed on the platen 26 to the other end. At this time, the moving operation is performed on the drum 1 indicated by the arrow 14.
0, and 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 acts on the light beam passing through lens 22 to form an electrostatic latent image on photoconductive surface 12 and partially discharge 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 includes three independent units 30,
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 overflows the lines of magnetic force and stands upright, forming a brush-like shape. When the electrostatic latent image on the photoconductive surface 12 and the partially discharged probe 16 come into contact with a brush-like developer,
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 toner, respectively. It is developed by attaching it to toner particles. 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 invention
Each developer unit is used to dispense one particle of toner to maintain a substantially constant concentration of toner particles in the developer. This operation maintains the quality of the copy at a satisfactory level. The developing device used in the copying machine shown in FIG. 1 and the relationship between it and the probe 16 will be explained later with reference to FIG. Similarly, the toner dispensing device and its relationship to probe 16 will be described later with reference to FIG. Drum 10 then rotates toward transfer station D where the powder image electrostatically adhered to photoconductive surface 12 and probe 16 is transferred to final support sheet 3.
Transferred to 6.

This support 36 can be of various types, but may be a sheet of plain paper or thermoplastic material. Transfer roll 3
8 is electrically biased and supports 36 in the direction of arrow 40
recirculate in the direction of 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.

Image support 36 is releasably secured on transfer drum 38 for movement into the recirculation path so that a series of toner images can be registered and superimposed thereon. 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 the drum 38 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. Next, the support 36 is removed from the transfer roll 38 by a peeling bar 56.
The image is separated from the image forming apparatus, and is placed on an endless 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 delivered to a tray 66 by an endless belt conveyor 62, and can be removed by the copying machine operator. 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 the photoconductive surface 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 generator (not shown) which is operative to neutralize the static charge remaining on the photoconductive surface 12 and the static charge on the residual toner, as well as the static charge on the probe. ). 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 disclosed in U.S. Patent No. 3,690,412.
The one listed in the number is appropriate. The above explanation should provide a sufficient understanding of the general operating principle of an electrostatic copying machine using the apparatus according to the present invention.

Turning now to the subject matter of the present invention, FIG. 2 shows the drum 10 with the 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 spaced apart from the photoconductive surface so that it can be moved within the copying machine to measure the charge distribution along the length of the mounted photoconductive surface 12. drum 10
The shaft 70 is a tubular member through which wiring can pass through the hollow center for connection to an external probe and associated electrical circuit. This electric circuit will be explained in detail later in the explanation of FIG. 4. The sliding ring 72 is
It operates to transmit electrical signals from the 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 various processing stations to adjust the individual stations. Referring now to FIG. 3, this is a partial cross-sectional view of probe 16 and portions of drum 10, with a transparent, generally conductive sheet 73 secured to photoconductive surface 12 as shown. There is.

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 transparent insulating member 78 is positioned through which a conductive member or wire 81 connected to the wire 81 is passed. 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, i.e. the photoconductor 12
The sum of the voltages across 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 type device having three thin films on an aluminum substrate, and is mounted flat on the contact surface of the surface of a photoconductive member. 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 so that the electrical characteristics of the processing station can be adjusted 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 γ3 preferably has a thickness of about 25 microns or less, and the transparent adhesive dielectric 80 also has a thickness of about 25 microns or less.
Preferably, the thickness is less than 5 microns, and photoconductive surface 12 is preferably about 60 microns 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 processed by one gain amplifier 84. Any amplifier with high impedance can be used in combination with the probe according to the present invention. The electrical output of amplifier 84 is further amplified by two-stage amplifiers 86 and 88, including a high impedance unit gain amplifier 90 and a capacitor 9.
The signal is sent to a hold circuit consisting of 2 and 2. However, due to the normally open contact 94, the signal from the amplifier is not always applied to this hold circuit. The logic circuit of a copying machine has
A circuit is provided that operates to close contact 94 at predetermined times so that high impedance unit gain amplifier 90
A sample voltage is applied across the . 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 probe has passed through each processing station, a signal is sent from the copying machine's logic circuit 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
The output is then relatively constant until 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 voltage magnitude of the next sample signal is different from the voltage of the first sample signal, capacitor 92 is recharged to this new voltage through contact 94 and amplifier 88 circuitry. 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 each 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 thus 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 each processing station. The circuit described above based on FIG. 4 will be referred to as number 98 hereinafter. Next, FIG. 5 will be explained. This figure shows a corona generating device 18 and a corona generating device 18,
A circuit for regulating the charging voltage is shown. 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 the corona electrode wire is made of stainless steel,
A coating of tungsten oxide on a non-corrosive material such as platinum or tungsten is preferred. This electrode wire 102 has an outer diameter of approximately 0.089 mm (0.08 mm).
．． It has a substantially uniform thickness of 0.035 inch). This corona electrode wire 102 extends along the longitudinal direction of the shield body 100, and both ends are connected to appropriate insulator protrusions. 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 generates an electrical output signal. This signal is sent to circuit 98 and converted to an output signal that is processed by logic circuit 104. It is preferable that the logic circuit 104 include a discrimination circuit for comparing the output signals from the circuit 98. This discrimination circuit may include a thyristor switch which is activated and remains in an on state when the output signal becomes greater than a reference voltage. A signal from the discrimination circuit changes the state of a flip-flop circuit, from which an output signal is generated. This output signal, after being amplified by a suitable amplifier, energizes the input controller. The output signal from this input controller is
Adjust the high voltage power supply 106. For example, the high voltage power supply 106 is preferably a constant current power supply that applies a voltage of about 7000 volts to the corona electrode wire 102 and flows a current of 400 ttA. Corona electrode wire 102 thus charges photoconductive surface 12 to a uniform voltage of approximately 900 volts. The output from the corona electrode wire 102 is regulated by the electrical signal from the probe 16, so that the output from the corona electrode wire 10
2 charges the probe 16 to approximately 900 volts despite changes in ambient conditions and aging of the photoconductive surface. 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 conductive 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 occurs, the voltage applied to the lamp changes around its nominal value to compensate for the change 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 and is representative of the current state of the photoconductive surface. The output signal from this circuit 98 is processed by logic circuit 112. Each developing unit 30
, 32 and 34 consist of magnetic developing rolls 115, 117 and 119 to which a bias voltage is applied as shown in FIG. Only the electrostatic latent image on photoconductive surface 12 that is present is developed. 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, conduction occurs. A thyristor switch can be used to continue the operation. The signal from this discrimination 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 is adapted to adjust the high voltage power supply that energizes developer rollers 115, 117 and 119. A total of three channels are provided, one for each of the logic circuit 112 and the ζ development units 30, 32 and 34. Generates another signal to the logic circuit &ζAND gate of the copier to activate the channel corresponding to the developer unit to be energized. It will be clear to those skilled in the art that if only one developer unit is used in a monochromatic copying machine, only one channel is required. A developing device using multiple developing units is disclosed in U.S. Patent Application No. 2,552.
No. 59 is mentioned, and its contents are related to the present application. The power supply 114 connects the developing rolls 115 and 117.
and 119 to apply 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
6 and about 6.3 mm (1/4 inch) thick urethane 118 is preferably casted on the circumferential surface. Moreover, on top of this cast urethane 118 layer, polyurethane 12
0 to a thickness of about 1 mil. The hardness of the transfer drum 38 is preferably about 10 to 30 on the shore A scale, and the resistivity is preferably about 108 to about 1011 ohm-cm. Power supply 122 applies a DC voltage to aluminum tube 116 by means such as a carbon brush and brass ring assembly (not shown). This bias voltage can vary from about 1500 volts to about 4500 volts and is properly adjusted depending on the signal generated by the probe 16.
The maximum force applied to the contact point between the photoconductive surface 12 of the drum 10 and the transfer drum 38 with the support 36 interposed is approximately 453 y (
(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 transfer of the toner image, circuitry 98 processes the signals from probe 16. This processed signal is sent to logic circuit 124. This logic circuit 124 is
It is preferable to use a discrimination circuit that compares the output signal sent from the circuit 98 with a reference value, and uses a thyristor switch that turns on when an input signal larger than the reference value is input to this discrimination circuit. can. 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 by a suitable amplifier, is applied to an input controller that adjusts the power supply 122 applying a bias voltage to the transfer monolith 38. Therefore, since the bias voltage of the transfer roll 38 changes depending on the state of the probe 16, it is possible to substantially optimize the transfer state. This is made possible by detecting the state of the probe 16. This method is a closed loop and automatic correction method since the bias voltage is changed on the next transfer and the errors displayed in the previous cycle are corrected. 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 11ζ predetermined colored toner particles.
All of the above containers are the same, so only one will be explained below. Therefore, in this example, toner particle storage container 1
It only touches on 26. This toner particle storage container 126 is
It is a tubular cylinder 132 with both ends closed, and a screen 134 is provided at the bottom of the tubular cylinder 132. Toner particles 136 are stored within tubular member 132 and rotate about a longitudinal axis of toner particle storage container 1261ζ. 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 connects logic circuit 14.
Generates an output signal that is processed with zero. 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 developer unit operates the yΦ gate, and the AND gate sends a control signal to the vibration motor 138 of the toner particle container corresponding to that 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. The amount of charge on the probe 16 is
The output signal of the probe 16 will vary depending on the concentration of the toner particles on the probe 16 since it will vary depending on the charge remaining on it after exposure and the charge the toner particles have. 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 approximately constant. In this way, the quality of the copy is maintained at the desired level. To summarize the foregoing description, an apparatus according to the present invention is adapted to be mounted on a photoconductive member and simultaneously passed through a processing station through which the photoconductive member passes.

The invention also operates to simulate a photoconductive member and generate electrical signals 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 each 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. For example, in the above embodiment, the probe 16 is described as being attached in principle through the bore 76 of the photoreceptor drum, but instead of this bore, a slot cut in the width direction of the drum 10 is used. A slot may be provided and the probe 16 may be placed within the slot. In this way, the probe 16 can be moved in the width direction of the drum 10, thereby making it possible to measure the amount of charge at various points on the drum 10. Separately, a photoconductive member surface 1 facing the probe 16 is provided with the probe 16 supported externally of the drum 10.
The amount of charge on 2 may be measured. For this purpose, probe 16 may be fixed to the frame of the copying machine, for example at a location downstream of charging station A, downstream of exposure station B, downstream of development station C or downstream of transfer station D.

[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. FIG. 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 photoconductive 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. 12...Photoconductive layer, 73...Transparent conductive layer, 74...
Conductive layer, 81... Conductive member.

Claims (1)

[Claims] 1. In a detection device for simulating a photoconductive member used in an electrostatic copying machine having a plurality of processing stations,
a conductive layer 74; a photoconductive layer 12 fixed to the conductive layer; a substantially transparent conductive layer 73 fixed to and insulated from the photoconductive layer; and insulated from the conductive layer and the photoconductive layer. A detection device comprising a conductive member 81 electrically connected to the transparent conductive layer. 2. The conductive member is supported together with the photoconductive layer, the conductive layer, and the transparent conductive layer, and is mounted at a position facing the photoconductive member at the rear of a processing station for charging the photoconductive member of a copying machine. The detection device of claim 1 further comprising support means 78 adapted to provide an integral detection device for measuring the amount of charge on the member. 3. The detection device according to claim 1, wherein a small hole is provided in a photoconductive member of an electrophotographic copying machine for attaching the photosensitive device, thereby detecting the amount of charge on the photoconductive member. 4 A slot extending in a direction intersecting the moving direction of the photoconductive member is provided in a portion of the photoconductive member, and a detection device is slid along the slot to detect the charge distribution in the longitudinal direction of the photoconductive member. The detection device according to claim 1, which is adapted to detect.