CA1098164A - Apparatus and method for noise immunity for control signals in electrostatographic processing machines - Google Patents
Apparatus and method for noise immunity for control signals in electrostatographic processing machinesInfo
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- CA1098164A CA1098164A CA275,363A CA275363A CA1098164A CA 1098164 A CA1098164 A CA 1098164A CA 275363 A CA275363 A CA 275363A CA 1098164 A CA1098164 A CA 1098164A
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/50—Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control
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- Microelectronics & Electronic Packaging (AREA)
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- Selective Calling Equipment (AREA)
- Signal Processing For Digital Recording And Reproducing (AREA)
- Arrangements For Transmission Of Measured Signals (AREA)
- Control Or Security For Electrophotography (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A system for controlling processing stations in an electrostatographic reproduction machine is provided. It includes a data processing unit that is shielded against electromagnetic radiation. Signals are transmitted through the shielding by means of electro-optic couplers. Means for determining a probable logic state of input signals includes at least one remote interface unit that is adapted to receive and store instruction signals periodically transmit-ted from the data processing unit. The interface unit provides control signals processor stations that are deter-mined by the instruction signals.
A system for controlling processing stations in an electrostatographic reproduction machine is provided. It includes a data processing unit that is shielded against electromagnetic radiation. Signals are transmitted through the shielding by means of electro-optic couplers. Means for determining a probable logic state of input signals includes at least one remote interface unit that is adapted to receive and store instruction signals periodically transmit-ted from the data processing unit. The interface unit provides control signals processor stations that are deter-mined by the instruction signals.
Description
This invention relates generally to electrostato-graphic reproduction machines and more particularly to apparatus for improving the integrity of control signals developed in a data processing unit and transmitted to the processing stations of the electrostatographic machine.
As electrostatographic reproduction machines have become larger and more complex, it has become advantageous to the control the processing stations with a data processing unit. The use of a central processing unit has provided numerous advantages in adaptability and flexibility in the electrostatographic machine operation. Typically, the data processing unit, in response to appropriate clocking and sensor input signals, can generate control signals. The logic signals from the data processing unit actuate control circuits for the processing station apparatus. The data pro-cessing unit transmits the control signals to a location which is typically remote. Moreover, it is possible during the transmission of the logic signals that noise can jeopardize the integrity of the transmission of the control signals.
Moreover, the electrostatographic reproduction machine can be a rich source of noise. For example, the corotron devices produce a varied noise spectrum as will the flash lamp current pulse.
It is known in the prior art to provide shielding for cables transmitting the logic control signals. This shielding can be both expensive and only partially successful for most practical shielding structures.
It is further known that logic signals can be encoded with additional information in the form of an error-correcting code such that the original logic signal can be reconstructed ~)9~
after transmission. However, such encoding techniques typically involve extensive electrical apparatus to implement and can provide an unacceptable complication.
In the presence of a potentially noisy environment, sampling techniques and multiple processing of the same infor-mation with decision logic to determine statistically the most probably correct logic state resulting from a signal manipula-tion operation may be used. The duplication of processing operations as well as the statistical decision information apparatus can provide unacceptable complications.
The pres2nt invention provides groups of instruction signals to be transmitted periodically to the remote interface units for controlling the performance of the electrostatographic processing operations. The instruction signals can be periodi-cally updated in a data processing unit on the basis of input signal information, or on the basis of a predetermined time sequence of the instruction signals. The control signals, transmitted from the data processing unit, are received in the remote interface unit and stored therein. Logic apparatus ~o examines the contents of the stored information and provides, in response to predetermine the combination of instruction logic signals, appropriate signals for control of the image processing apparatus associated with the remote processing station, In the event that activation of a remote image pro-cessing device is to be performed at a predetermined time, the control signal activating the processing apparatus is transmitted following a transmission of the preselected sensitizing signal. When the sensitizing and control signals are transmitted in a pre-established time relationship, an 1~98~64 appropriate image processing device activation signal is thereafter generated.
Apparatus is included at the remote station inter-face unit for automatically inactivating the remote station processing apparatus in the event that a control signal is not transmitted within a predetermined time. In addition, a return path is provided for the transmitted signals as a check against systematic errors.
In addition to shielding around the data processing unit, other devices are incorporated to aid in rejection of noise signals. The data processing unit is accessible only through elbctro-optic couplers. Input signals are sampled to enhance the logic state identification reliability.
Thus, in accordance with one aspect of this invention there is provided a method for operating the processing stations of an electrostatographic reproduction unit under control of a data processing unit comprising the steps of: periodically send-ing a block of control information signals from said data pro-cessing unit to a remote unit; storing said block of control information signals in said remote unit; removing said block of control information signals and decoding said control informa-tion signals to provide control signals for the processing stations of said reproduction unit associated with said remote unit; and applying said control signals to said process-ing stations of said reproduction unit associated with saidremote unit.
In accordance with another aspect of this invention there is provided a system for controlling processing stations of an electrostatographic machine comprising: at least one remote interface unit, said interface unit applying control ~ ?
~981G4 signals from instruction signals to processing stations asso-ciated with said remote interface unit and including signal storing means for storing a preset block of said instruction sic~nals for application as said control signals; and a data processing unit, said data processing unit in at least partial response to an operational status of said electrostatographic machine periodically transmitting said preset block of instruction signals to said remote interface unit, said remote interface unit including apparatus for deriving said control 10 signals from said instruction signals stored in said remote interface unit.
These and other features of the invention will be understood upon reading the following description in conjunction with the figures which include:
Figure 1 is a schematic diagram of the apparatus controlling the processing stations of an electrostatographic machine according to the prior art.
Figure 2 is a schematic diagram of the apparatus controlling the processing stations of an electrostatographic 20 machine according to the present invention.
Figure 3 is a schematic diagram of the remote inter-face unit utilized in controlling processing stations of an electrostatographic machine.
Figure 4 is a schematic diagram of apparatus associated 25 with the data processing unit to enhance the lmmunity against noise.
-4a-1098~64 Referring now to Figure 1, a schematic diagram of, a system for controlling the processing stations of an electro-statographic reproduction machine by means of a data processing uni.t, according to the prior art is shown. A data processing unit 20 receives input signals from the electrostatographic machine sensors 10. The input signals can be status signals, signals identifying a position of a copy sheet, clocking signals derived from the machine components, fault condition signals or any other signal which can be utilized to control the machine processing stations. On the basis of the input signals, the data processing unit 20 produces appropriate control signals which are applied to signal actuated apparatus 31 through 34 of the electrostatographic machine processing stations. The signal actuated apparatus 31 through 34 can include solenoids, flash lamps, etc., and the electronic cir-cuits actuating these components. The processing stations can include sorter, paper handling devices and devices for which the operation should be determined by the actual image pro-cessing of the electrostatographic machine.
As discussed above, certain components of electro-statographic reproduction machine such as the corotrons and the flash lamps, provide a rich source of electromagnetic noise. This noise can enter the system shown in Figure 1 by several paths, The machine sensors 10 can provide erroneous output signals in the presence of noise and the integrity of the sensor output signals as applied to data processing unit 20 can be jeopardized by noise entering the electrical connections coupling the sensors and the data processing unit.
Similarly, the integrity of the control signals applied from the data processing unit 20 to the signal actuated apparatus 31 ~L~9816~
through 34 can be impaired. But more importantly, the integrity of the data processing unit can be jeopardized by electromagnetic noise. For example, the logical mini-pulation by the data processing unit of the input signals necessary for determination of the processing station operation can be vulnerable to noise. And as the data processing unit becomes increasingly dependent on stored programs capable of being electrically altered for greater operational flexibility, the accuracy of the stored control program can be impaired.
Referring next to Figure 2, a schematic diagram of a system for controlling the processing stations of an electro-statographic reproduction machine by means of a data processing unit, according to the present invention is shown. The data processing unit 20 receives input signals from the electro-statographic machine sensors 10. However, instead of delivery control signals directly to the signal actuated apparatus, instruction signals are delivered to remote interface units 21 through 22. The instruction signals are decoded by the apparatus of the remote interface unit, thereby obtaining control signals which are applied to the signal actuated apparatus of the electromagnetic machine.
In this system, the data processing unit 20 can be shielded from the electromagnetic noise generated by components of the reproduction machine. This shielding can take the form of an appropriate material (indicated by covering 19 in Figure 2). The coupling of logic signals into and out of data processing unit 20 can be accomplished by electro-optic elements, thereby eliminating direct electrical coupling to the data processing unit. Shielding can also be accomplished by removing the data processing unit to a distance from the .
~9~3~64 reproduction components for which the resulting electro-magnetic noise is sufficiently diminished for accurate operation of the data processing unit. In this manner, the operation of the data processing system can be rendered more reliable.
In an effort to increase the accuracy of the input signals, the data processing unit can sample the input signals and by appropriate logic apparatus, can statistically determine the most probably logical state of an input signal.
The remote interface unit can be equipped with apparatus to store the instruction signals. Accurate transfer of the instruction signals between the data processing unit 20 and the remote interface units can be enhanced by several methods. The electrical couplings between the data processing unit and the remote interface units 21 through 22 can be shielded as by shield material 18. The accuracy of instruction signal transfer can be enhanced by having the instruction signals encoded by the data processing unit in a format which can tolerate the presence of noise, i.e., in an error-correcting code, and by having appropriate decoding apparatus in the remote interface units. Accuracy of instruction signal transfer can be enhanced by the addition of electrical couplings from the remote interface unit to the data processing unit and the addition of apparatus for periodically integrating the instruction signals stored in the remote interface unit. A
still further method of enhancing the accuracy of the instruc-tion signals stored in the remote interface unit is to refresh these instruction signals periodically, thereby correcting and errors which can occur due to noise. Finally, the remote interface units themselves can be shielded, if necessary to ~9~64 increase the reliability of signals entered into the remote interface units, Because the remote interface units are located in the preferred embodiment relatively close to the related signal actuate apparatus, the shortened electrical couplings provide relative immunity to noise induced by electromagnetic radiation as compared to the longer electrical couplings.
Referring next to Figure 3, a schematic diagram of the apparatus comprising the remote interface unit accord-ing to the preferred embodiment is shown. The data processingunit applies two sets of signals to a remote interface unit (21), a clocking signal and the instruction signal. The instruction signals contain logical signals which have encoded information containing the control of the signal actuated reproduction machine. Each clocking signal is sent with a slight delay after the transmission of an instruction signal.
The clocking signal sequence has a precursor signal applied to clock signal decoder 42. The precursor signal applies an enabling logic signal to a first input terminal of logic AND
gate 49, an enabling logic signal to a first input terminal of logic AND gate 46 and a logic signal to timer 45.
~ Timer 45 is a safety device and a negative logic signal is normally applied to the output terminal of timer 45. A signal inverting stage associated with a second terminal of logic AND gate 46 enables gate 46. However, should a clocking pulse not be applied to an input terminal of timer 45, a positive pulse will be applied to the output terminal of timer 45, disabling gate 46 and resetting shift register 43. Timer 46 must be reactivated before data can be entered 31ti4 in the latch circuits.
After the precursor pulse, positive logic (clocking) signals are transmitted, Immediately before each of the clocking signais an instruction signal is applied to the data processing unit signal decoder 41. The data decoding unit, after determining whether the applied signal indicates a positive or negative logic signal, applies the appropriate logic signal to an input terminal of shift register 93. The delayed clocking signal is applied through clock signal decoder 10 42, through enabled gate 49 to the clock terminal of shift register 43. Thus, the logic instruction signals are entered and shifted in the shift register. In the preferred embodiment, the instruction signal contains information relating to 40 logic signals and shift register 43 has 40 elements. During the loading of the logic signals in shift register 43, gate 46 applies a logic signal to latch circuits 44. Latch circuits 44 then receive the signals from the shift register 43 and after the transmission of the group of instruction signals, the positive logic signal is removed from the first input 20 terminal of gate 46, thereby storing the logic signals of register 43 in the latch circuits 44.
The logic signals stored in latch circuits 44 are fed via electrical couplings 51 through 53 to transmitted signal decoder 47. The signal decoder identifies predetermined patterns of logic signals in the latch circuits and in response provides appropriate signals to electrical couplings 61 through 63. The signals applied to couplings 61 through 63 control the associated signal actuated apparatus.
To provide partial verification of the integrity of 30 the transmitted logic signals, the logic signals from two data ~98~
positions, indicated in Figure 3 by latch circuit electrical couplings 52 and 53, are returned to the data processing unit via electrical coupling 48. These two data positions are dedicated in the preferred e~bodiment to this checking function. One position 52 is arbitrarily, selected to pro-vide a negative logic signal while the other checking location 53 is ch~sen because the logic signal associated therewith was shifted the length of shift register 43.
As described, the transmitted signal decoder 47 controls one or more of the copy processing components of the electrostatographic machine. These components comprise mechan-ical devices, the inertia of which prohibits response to occa-sional errors in the signal. Thus, even in the presence of noise, sufficient to generate errors in the control signals, these errors will have minimal effect on operation. The use of synchronized clocking signals with instruction signal trans-mission also enhances noise immunity.
It will be further understood that for the devices, such as a flash lamp in which relatively precise activation is required, the present apparatus envisions a two stage process. A series of sensitizing signals is first transmitted to the apparatus. The sensitizing signals prepare the apparatus to be triggered by a succeeding trigger signal. In fact a plurality of trigger signals are utilized. In the presence of noise, the operation is as follows. The series of sensiti-zing signals will prepare the apparatus for response to the trigger signals. Only one of the series of sensitizing signals has to be error free to sensitize the apparatus. Error free trigger signals will provide an accurate device activation.
In the presence of noise, the device activation can be early 1(~98~6~
or late. However, because the number and repetition rate of the sensitizing signals and trigger signals, the resulting copy will be acceptable. For example, in the case of the flash lamp excitation, the registration of the copy on the copy sheet will have a displacement, which except in critical circumstances will not be noticeable.
Referring now to Figure 4, a schematic diagram of data processing unit 20 is there shown. In the preferred embodiment, an appropriate shielding material 19 completely encloses the data processing unit. To enter or extract signals from the shielded data processing unit, three groups of electro-optic elements 63, 64 and 66 are utilized. Each electro-optic element is comprised of a light emitting diode 71 and a light sensitive element 72. A positive logic can be defined as a signal of sufficient amplitude to cause diode 71 to generate light 73 of sufficient intensity diode to activate the light-sensitive element 72. A negative logic signal can be defined as signal of insufficient amplitude to produce a light above the threshold level in the light sensitive element 72. Thus, logic signals can be optically transferred between elements 71, 72 eliminating direct electrical coupling and the attendant possibility for the introduction of noise.
Input signals from the sensor elements are applied to predetermined matrix locations in input signal matrix 62.
It will be clear to those skilled in the art that analog signals can be reduced to a digital format, for example, by analog-to-digital converters. In the preferred embodiment, a thirty-two column and eight row matrix is utilized. The data processing unit applies preselected logic signals to a group of five electro-optic elements 63. The five logic lW83~6~
signals transferred through the shielding l9 are applied to address decoding apparatus 61. Output signals of apparatus 61 activate one of the thirty-two matrix column, the particular activated column determined by the transferred logic signals.
The eight input signals associated with the rows of the addressed column are applied to the eight electro-optic elements 66. Within the shielding l9, a decision process indi-cated schematically by elements 64 through 65 determine, in the presence of noise, the nature of the logic computer, i.e., whether the logic signal is positive or negative. It is clear that several algorithms can be utilized to increase confidence in the identification of the logic signal. For example, a time averaging system can be utilized. In the preferred embodiment, the input signal is sampled during a first clock signal by sample and hold circuit 81. A second clock signal activates compare circuit 82 to compare the output of circuit 81 with the input signal. When the two samples measure the same logic rate, amplifier gate 84 is activated, applying to an output terminal the logic state of circuit 81. When, however, the two samples differ, a signal is applied to delay circuit 83.
An output signal from the delay circuit 83 cause the sample and hold circuit 81 to determine the logic state of an input signal during another sample period. The delay circuit also actuates amplifier gate 84 causing the stored change state to be applied to the output terminal. The sampling technique can be implemented by comparing the output signal of a sample and hold circuit (first sample) with the second sample via logic circuits. In case of logic signal identity, the identified logic state is the signal utilized. When the output signal of the sample and hold circuit is different from the second sample, the ~1398~4 logic circuit selects the state identified by the third sample, The data processing unit responsible for the particular input signals entared into the data processing unit, can then proceed with appropriate manipulation.
This manipulation eventually results in eight forty-bit instruction signal groups stored in a scratch pad memory of the data processing unit. Each forty-bit instruction signal group is associated with a remote interface unit and can be decoded by the remote interface unit to provide control signals for controlling apparatus of the electrostatic machine associated with each remote interface unit, The eight instruc-tion signals are periodically applied to the associated eight remote interface units along with clocking signals, The instruction signal groups and the clocking signals are extracted from the shielding data processing unit via electro-optic elements 67, The instruction signal groups along with clocking signals are delivered to the remote interface units approximately every millisecond, or when an instruction signal change results in a control signal which must be executed immediately, The instruction signal groups are updated in the scratch pad memory by the data processing unit in response to input and timing signals, The above description is intended to illustrate the operation of the preferred embodiments and is not meant to limit the scope of the invention, Scope of the invention is to be limited only by the following claims, Many variations will be apparent to one skilled in the art that would yet be encompassed by the spirit and scope of the invention,
As electrostatographic reproduction machines have become larger and more complex, it has become advantageous to the control the processing stations with a data processing unit. The use of a central processing unit has provided numerous advantages in adaptability and flexibility in the electrostatographic machine operation. Typically, the data processing unit, in response to appropriate clocking and sensor input signals, can generate control signals. The logic signals from the data processing unit actuate control circuits for the processing station apparatus. The data pro-cessing unit transmits the control signals to a location which is typically remote. Moreover, it is possible during the transmission of the logic signals that noise can jeopardize the integrity of the transmission of the control signals.
Moreover, the electrostatographic reproduction machine can be a rich source of noise. For example, the corotron devices produce a varied noise spectrum as will the flash lamp current pulse.
It is known in the prior art to provide shielding for cables transmitting the logic control signals. This shielding can be both expensive and only partially successful for most practical shielding structures.
It is further known that logic signals can be encoded with additional information in the form of an error-correcting code such that the original logic signal can be reconstructed ~)9~
after transmission. However, such encoding techniques typically involve extensive electrical apparatus to implement and can provide an unacceptable complication.
In the presence of a potentially noisy environment, sampling techniques and multiple processing of the same infor-mation with decision logic to determine statistically the most probably correct logic state resulting from a signal manipula-tion operation may be used. The duplication of processing operations as well as the statistical decision information apparatus can provide unacceptable complications.
The pres2nt invention provides groups of instruction signals to be transmitted periodically to the remote interface units for controlling the performance of the electrostatographic processing operations. The instruction signals can be periodi-cally updated in a data processing unit on the basis of input signal information, or on the basis of a predetermined time sequence of the instruction signals. The control signals, transmitted from the data processing unit, are received in the remote interface unit and stored therein. Logic apparatus ~o examines the contents of the stored information and provides, in response to predetermine the combination of instruction logic signals, appropriate signals for control of the image processing apparatus associated with the remote processing station, In the event that activation of a remote image pro-cessing device is to be performed at a predetermined time, the control signal activating the processing apparatus is transmitted following a transmission of the preselected sensitizing signal. When the sensitizing and control signals are transmitted in a pre-established time relationship, an 1~98~64 appropriate image processing device activation signal is thereafter generated.
Apparatus is included at the remote station inter-face unit for automatically inactivating the remote station processing apparatus in the event that a control signal is not transmitted within a predetermined time. In addition, a return path is provided for the transmitted signals as a check against systematic errors.
In addition to shielding around the data processing unit, other devices are incorporated to aid in rejection of noise signals. The data processing unit is accessible only through elbctro-optic couplers. Input signals are sampled to enhance the logic state identification reliability.
Thus, in accordance with one aspect of this invention there is provided a method for operating the processing stations of an electrostatographic reproduction unit under control of a data processing unit comprising the steps of: periodically send-ing a block of control information signals from said data pro-cessing unit to a remote unit; storing said block of control information signals in said remote unit; removing said block of control information signals and decoding said control informa-tion signals to provide control signals for the processing stations of said reproduction unit associated with said remote unit; and applying said control signals to said process-ing stations of said reproduction unit associated with saidremote unit.
In accordance with another aspect of this invention there is provided a system for controlling processing stations of an electrostatographic machine comprising: at least one remote interface unit, said interface unit applying control ~ ?
~981G4 signals from instruction signals to processing stations asso-ciated with said remote interface unit and including signal storing means for storing a preset block of said instruction sic~nals for application as said control signals; and a data processing unit, said data processing unit in at least partial response to an operational status of said electrostatographic machine periodically transmitting said preset block of instruction signals to said remote interface unit, said remote interface unit including apparatus for deriving said control 10 signals from said instruction signals stored in said remote interface unit.
These and other features of the invention will be understood upon reading the following description in conjunction with the figures which include:
Figure 1 is a schematic diagram of the apparatus controlling the processing stations of an electrostatographic machine according to the prior art.
Figure 2 is a schematic diagram of the apparatus controlling the processing stations of an electrostatographic 20 machine according to the present invention.
Figure 3 is a schematic diagram of the remote inter-face unit utilized in controlling processing stations of an electrostatographic machine.
Figure 4 is a schematic diagram of apparatus associated 25 with the data processing unit to enhance the lmmunity against noise.
-4a-1098~64 Referring now to Figure 1, a schematic diagram of, a system for controlling the processing stations of an electro-statographic reproduction machine by means of a data processing uni.t, according to the prior art is shown. A data processing unit 20 receives input signals from the electrostatographic machine sensors 10. The input signals can be status signals, signals identifying a position of a copy sheet, clocking signals derived from the machine components, fault condition signals or any other signal which can be utilized to control the machine processing stations. On the basis of the input signals, the data processing unit 20 produces appropriate control signals which are applied to signal actuated apparatus 31 through 34 of the electrostatographic machine processing stations. The signal actuated apparatus 31 through 34 can include solenoids, flash lamps, etc., and the electronic cir-cuits actuating these components. The processing stations can include sorter, paper handling devices and devices for which the operation should be determined by the actual image pro-cessing of the electrostatographic machine.
As discussed above, certain components of electro-statographic reproduction machine such as the corotrons and the flash lamps, provide a rich source of electromagnetic noise. This noise can enter the system shown in Figure 1 by several paths, The machine sensors 10 can provide erroneous output signals in the presence of noise and the integrity of the sensor output signals as applied to data processing unit 20 can be jeopardized by noise entering the electrical connections coupling the sensors and the data processing unit.
Similarly, the integrity of the control signals applied from the data processing unit 20 to the signal actuated apparatus 31 ~L~9816~
through 34 can be impaired. But more importantly, the integrity of the data processing unit can be jeopardized by electromagnetic noise. For example, the logical mini-pulation by the data processing unit of the input signals necessary for determination of the processing station operation can be vulnerable to noise. And as the data processing unit becomes increasingly dependent on stored programs capable of being electrically altered for greater operational flexibility, the accuracy of the stored control program can be impaired.
Referring next to Figure 2, a schematic diagram of a system for controlling the processing stations of an electro-statographic reproduction machine by means of a data processing unit, according to the present invention is shown. The data processing unit 20 receives input signals from the electro-statographic machine sensors 10. However, instead of delivery control signals directly to the signal actuated apparatus, instruction signals are delivered to remote interface units 21 through 22. The instruction signals are decoded by the apparatus of the remote interface unit, thereby obtaining control signals which are applied to the signal actuated apparatus of the electromagnetic machine.
In this system, the data processing unit 20 can be shielded from the electromagnetic noise generated by components of the reproduction machine. This shielding can take the form of an appropriate material (indicated by covering 19 in Figure 2). The coupling of logic signals into and out of data processing unit 20 can be accomplished by electro-optic elements, thereby eliminating direct electrical coupling to the data processing unit. Shielding can also be accomplished by removing the data processing unit to a distance from the .
~9~3~64 reproduction components for which the resulting electro-magnetic noise is sufficiently diminished for accurate operation of the data processing unit. In this manner, the operation of the data processing system can be rendered more reliable.
In an effort to increase the accuracy of the input signals, the data processing unit can sample the input signals and by appropriate logic apparatus, can statistically determine the most probably logical state of an input signal.
The remote interface unit can be equipped with apparatus to store the instruction signals. Accurate transfer of the instruction signals between the data processing unit 20 and the remote interface units can be enhanced by several methods. The electrical couplings between the data processing unit and the remote interface units 21 through 22 can be shielded as by shield material 18. The accuracy of instruction signal transfer can be enhanced by having the instruction signals encoded by the data processing unit in a format which can tolerate the presence of noise, i.e., in an error-correcting code, and by having appropriate decoding apparatus in the remote interface units. Accuracy of instruction signal transfer can be enhanced by the addition of electrical couplings from the remote interface unit to the data processing unit and the addition of apparatus for periodically integrating the instruction signals stored in the remote interface unit. A
still further method of enhancing the accuracy of the instruc-tion signals stored in the remote interface unit is to refresh these instruction signals periodically, thereby correcting and errors which can occur due to noise. Finally, the remote interface units themselves can be shielded, if necessary to ~9~64 increase the reliability of signals entered into the remote interface units, Because the remote interface units are located in the preferred embodiment relatively close to the related signal actuate apparatus, the shortened electrical couplings provide relative immunity to noise induced by electromagnetic radiation as compared to the longer electrical couplings.
Referring next to Figure 3, a schematic diagram of the apparatus comprising the remote interface unit accord-ing to the preferred embodiment is shown. The data processingunit applies two sets of signals to a remote interface unit (21), a clocking signal and the instruction signal. The instruction signals contain logical signals which have encoded information containing the control of the signal actuated reproduction machine. Each clocking signal is sent with a slight delay after the transmission of an instruction signal.
The clocking signal sequence has a precursor signal applied to clock signal decoder 42. The precursor signal applies an enabling logic signal to a first input terminal of logic AND
gate 49, an enabling logic signal to a first input terminal of logic AND gate 46 and a logic signal to timer 45.
~ Timer 45 is a safety device and a negative logic signal is normally applied to the output terminal of timer 45. A signal inverting stage associated with a second terminal of logic AND gate 46 enables gate 46. However, should a clocking pulse not be applied to an input terminal of timer 45, a positive pulse will be applied to the output terminal of timer 45, disabling gate 46 and resetting shift register 43. Timer 46 must be reactivated before data can be entered 31ti4 in the latch circuits.
After the precursor pulse, positive logic (clocking) signals are transmitted, Immediately before each of the clocking signais an instruction signal is applied to the data processing unit signal decoder 41. The data decoding unit, after determining whether the applied signal indicates a positive or negative logic signal, applies the appropriate logic signal to an input terminal of shift register 93. The delayed clocking signal is applied through clock signal decoder 10 42, through enabled gate 49 to the clock terminal of shift register 43. Thus, the logic instruction signals are entered and shifted in the shift register. In the preferred embodiment, the instruction signal contains information relating to 40 logic signals and shift register 43 has 40 elements. During the loading of the logic signals in shift register 43, gate 46 applies a logic signal to latch circuits 44. Latch circuits 44 then receive the signals from the shift register 43 and after the transmission of the group of instruction signals, the positive logic signal is removed from the first input 20 terminal of gate 46, thereby storing the logic signals of register 43 in the latch circuits 44.
The logic signals stored in latch circuits 44 are fed via electrical couplings 51 through 53 to transmitted signal decoder 47. The signal decoder identifies predetermined patterns of logic signals in the latch circuits and in response provides appropriate signals to electrical couplings 61 through 63. The signals applied to couplings 61 through 63 control the associated signal actuated apparatus.
To provide partial verification of the integrity of 30 the transmitted logic signals, the logic signals from two data ~98~
positions, indicated in Figure 3 by latch circuit electrical couplings 52 and 53, are returned to the data processing unit via electrical coupling 48. These two data positions are dedicated in the preferred e~bodiment to this checking function. One position 52 is arbitrarily, selected to pro-vide a negative logic signal while the other checking location 53 is ch~sen because the logic signal associated therewith was shifted the length of shift register 43.
As described, the transmitted signal decoder 47 controls one or more of the copy processing components of the electrostatographic machine. These components comprise mechan-ical devices, the inertia of which prohibits response to occa-sional errors in the signal. Thus, even in the presence of noise, sufficient to generate errors in the control signals, these errors will have minimal effect on operation. The use of synchronized clocking signals with instruction signal trans-mission also enhances noise immunity.
It will be further understood that for the devices, such as a flash lamp in which relatively precise activation is required, the present apparatus envisions a two stage process. A series of sensitizing signals is first transmitted to the apparatus. The sensitizing signals prepare the apparatus to be triggered by a succeeding trigger signal. In fact a plurality of trigger signals are utilized. In the presence of noise, the operation is as follows. The series of sensiti-zing signals will prepare the apparatus for response to the trigger signals. Only one of the series of sensitizing signals has to be error free to sensitize the apparatus. Error free trigger signals will provide an accurate device activation.
In the presence of noise, the device activation can be early 1(~98~6~
or late. However, because the number and repetition rate of the sensitizing signals and trigger signals, the resulting copy will be acceptable. For example, in the case of the flash lamp excitation, the registration of the copy on the copy sheet will have a displacement, which except in critical circumstances will not be noticeable.
Referring now to Figure 4, a schematic diagram of data processing unit 20 is there shown. In the preferred embodiment, an appropriate shielding material 19 completely encloses the data processing unit. To enter or extract signals from the shielded data processing unit, three groups of electro-optic elements 63, 64 and 66 are utilized. Each electro-optic element is comprised of a light emitting diode 71 and a light sensitive element 72. A positive logic can be defined as a signal of sufficient amplitude to cause diode 71 to generate light 73 of sufficient intensity diode to activate the light-sensitive element 72. A negative logic signal can be defined as signal of insufficient amplitude to produce a light above the threshold level in the light sensitive element 72. Thus, logic signals can be optically transferred between elements 71, 72 eliminating direct electrical coupling and the attendant possibility for the introduction of noise.
Input signals from the sensor elements are applied to predetermined matrix locations in input signal matrix 62.
It will be clear to those skilled in the art that analog signals can be reduced to a digital format, for example, by analog-to-digital converters. In the preferred embodiment, a thirty-two column and eight row matrix is utilized. The data processing unit applies preselected logic signals to a group of five electro-optic elements 63. The five logic lW83~6~
signals transferred through the shielding l9 are applied to address decoding apparatus 61. Output signals of apparatus 61 activate one of the thirty-two matrix column, the particular activated column determined by the transferred logic signals.
The eight input signals associated with the rows of the addressed column are applied to the eight electro-optic elements 66. Within the shielding l9, a decision process indi-cated schematically by elements 64 through 65 determine, in the presence of noise, the nature of the logic computer, i.e., whether the logic signal is positive or negative. It is clear that several algorithms can be utilized to increase confidence in the identification of the logic signal. For example, a time averaging system can be utilized. In the preferred embodiment, the input signal is sampled during a first clock signal by sample and hold circuit 81. A second clock signal activates compare circuit 82 to compare the output of circuit 81 with the input signal. When the two samples measure the same logic rate, amplifier gate 84 is activated, applying to an output terminal the logic state of circuit 81. When, however, the two samples differ, a signal is applied to delay circuit 83.
An output signal from the delay circuit 83 cause the sample and hold circuit 81 to determine the logic state of an input signal during another sample period. The delay circuit also actuates amplifier gate 84 causing the stored change state to be applied to the output terminal. The sampling technique can be implemented by comparing the output signal of a sample and hold circuit (first sample) with the second sample via logic circuits. In case of logic signal identity, the identified logic state is the signal utilized. When the output signal of the sample and hold circuit is different from the second sample, the ~1398~4 logic circuit selects the state identified by the third sample, The data processing unit responsible for the particular input signals entared into the data processing unit, can then proceed with appropriate manipulation.
This manipulation eventually results in eight forty-bit instruction signal groups stored in a scratch pad memory of the data processing unit. Each forty-bit instruction signal group is associated with a remote interface unit and can be decoded by the remote interface unit to provide control signals for controlling apparatus of the electrostatic machine associated with each remote interface unit, The eight instruc-tion signals are periodically applied to the associated eight remote interface units along with clocking signals, The instruction signal groups and the clocking signals are extracted from the shielding data processing unit via electro-optic elements 67, The instruction signal groups along with clocking signals are delivered to the remote interface units approximately every millisecond, or when an instruction signal change results in a control signal which must be executed immediately, The instruction signal groups are updated in the scratch pad memory by the data processing unit in response to input and timing signals, The above description is intended to illustrate the operation of the preferred embodiments and is not meant to limit the scope of the invention, Scope of the invention is to be limited only by the following claims, Many variations will be apparent to one skilled in the art that would yet be encompassed by the spirit and scope of the invention,
Claims (5)
1. A method of operating the processing stations of an electrostatographic reproduction unit under control of a data processing unit comprising the steps of: periodically sending a block of control information signals from said data processing unit to a remote unit; storing said block of control information signals in said remote unit; removing said block of control information signals and decoding said control information signals to provide control signals for the processing stations of said reproduction unit associated with said remote unit; and applying said control signals to said processing stations of said reproduction unit associated with said remote unit.
2. The method of claim 1 including the steps of stor-ing control information signals in said remote unit in response to clocking signals, and alternating said control information signals with said clocking signals when sending control infor-mation signals to said remote unit.
3. The method according to claim 2 including the step of sending a precurser signal before said control information signals to ready said remote unit for receipt of the next block of said control information signals.
4. A system for controlling processing stations of an electrostatographic machine comprising: at least one remote interface unit, said interface unit applying control signals from instruction signals to processing stations associated with said remote interface unit and including signal storing means for storing a preset block of said instruction signals for application as said control signals; and a data processing unit, said data processing unit in at least partial response to an operational status of said electrostatographic machine periodically transmitting said preset block of instruction signals to said remote interface unit, said remote interface unit including apparatus for deriving said control signals from said instruction signals stored in said remote inter-face unit.
5. The system for controlling an electrostatographic machine in claim 3 including timing means for inactivating said signal storing means on a predetermined interruption during transmittal of said instruction signals.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US67710976A | 1976-04-15 | 1976-04-15 | |
| US677,109 | 1976-04-15 | ||
| US05/677,110 US4111544A (en) | 1976-04-15 | 1976-04-15 | Apparatus and method for noise immunity for control signals in electrostatographic processing machines |
| US677,110 | 1976-04-15 | ||
| US05/677,108 US4111543A (en) | 1976-04-15 | 1976-04-15 | Apparatus and method for noise immunity in distributing control signals in electrostatographic processing machines |
| US677,108 | 1976-04-15 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1098164A true CA1098164A (en) | 1981-03-24 |
Family
ID=27418315
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA275,363A Expired CA1098164A (en) | 1976-04-15 | 1977-04-01 | Apparatus and method for noise immunity for control signals in electrostatographic processing machines |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS52127339A (en) |
| BR (1) | BR7702289A (en) |
| CA (1) | CA1098164A (en) |
| DE (1) | DE2710479C2 (en) |
| FR (1) | FR2348513A1 (en) |
| GB (1) | GB1532106A (en) |
| NL (1) | NL7703987A (en) |
| SE (1) | SE415302B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2377660A1 (en) * | 1977-01-12 | 1978-08-11 | Xerox Corp | Computerised copying machine optical coupler control - has master with transmitter and receiver linked to counter-parts on units via cable |
| JPS56151947A (en) * | 1980-04-26 | 1981-11-25 | Canon Inc | Image former having diagnosis function |
| JPS59210455A (en) * | 1983-05-02 | 1984-11-29 | ゼロツクス・コ−ポレ−シヨン | Control system for electrophotographic printer |
| JPS6031156A (en) * | 1983-07-29 | 1985-02-16 | Sharp Corp | Copying machine |
| JPH0644165B2 (en) * | 1984-08-13 | 1994-06-08 | 富士ゼロックス株式会社 | Electronic copier control device |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3493760A (en) * | 1966-12-14 | 1970-02-03 | Us Army | Optical isolator for electric signals |
| US3680045A (en) * | 1969-09-10 | 1972-07-25 | Applied Digital Data Syst | Data transmission echoing unit |
| FR2205224A5 (en) * | 1972-09-29 | 1974-05-24 | Materiel Telephonique | |
| US3914047A (en) * | 1973-10-01 | 1975-10-21 | Eastman Kodak Co | Synchronizing control apparatus for electrophotographic apparatus utilizing digital computer |
| US3944360A (en) * | 1974-08-12 | 1976-03-16 | Xerox Corporation | Programmable controller for controlling reproduction machines |
| US3940210A (en) * | 1974-08-12 | 1976-02-24 | Xerox Corporation | Programmable controller for controlling reproduction machines |
| US3936600A (en) * | 1974-08-21 | 1976-02-03 | World Computer Corporation | Keyboard-printer terminal interface for data processing |
| FR2284928A1 (en) * | 1974-09-16 | 1976-04-09 | Honeywell Bull Soc Ind | Data connection interface for computer - enables two-way traffic between fast acting central processor and slow speed peripheral units |
| JPS6039232A (en) * | 1983-08-12 | 1985-03-01 | Nippon Telegr & Teleph Corp <Ntt> | Tablet |
-
1977
- 1977-03-10 DE DE19772710479 patent/DE2710479C2/en not_active Expired
- 1977-04-01 CA CA275,363A patent/CA1098164A/en not_active Expired
- 1977-04-06 SE SE7704047A patent/SE415302B/en not_active IP Right Cessation
- 1977-04-08 JP JP4128977A patent/JPS52127339A/en active Pending
- 1977-04-12 NL NL7703987A patent/NL7703987A/en not_active Application Discontinuation
- 1977-04-12 BR BR7702289A patent/BR7702289A/en unknown
- 1977-04-14 GB GB1548077A patent/GB1532106A/en not_active Expired
- 1977-04-15 FR FR7711517A patent/FR2348513A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| DE2710479A1 (en) | 1977-10-27 |
| FR2348513A1 (en) | 1977-11-10 |
| FR2348513B1 (en) | 1983-10-07 |
| NL7703987A (en) | 1977-10-18 |
| SE415302B (en) | 1980-09-22 |
| JPS52127339A (en) | 1977-10-25 |
| SE7704047L (en) | 1977-10-16 |
| GB1532106A (en) | 1978-11-15 |
| BR7702289A (en) | 1978-01-17 |
| DE2710479C2 (en) | 1986-09-25 |
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| MKEX | Expiry |