US3705289A - Electronic copying equipment with controlled heater - Google Patents

Electronic copying equipment with controlled heater Download PDF

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Publication number
US3705289A
US3705289A US182986A US3705289DA US3705289A US 3705289 A US3705289 A US 3705289A US 182986 A US182986 A US 182986A US 3705289D A US3705289D A US 3705289DA US 3705289 A US3705289 A US 3705289A
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US
United States
Prior art keywords
signal
output terminal
energizing
electrostatic copying
set forth
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US182986A
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English (en)
Inventor
Roland Szostak
Karl Hartwig
Gunter Maurischat
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Agfa Gevaert AG
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Agfa Gevaert AG
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Filing date
Publication date
Priority claimed from DE19702048076 external-priority patent/DE2048076C3/de
Application filed by Agfa Gevaert AG filed Critical Agfa Gevaert AG
Application granted granted Critical
Publication of US3705289A publication Critical patent/US3705289A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00—Control of temperature
    • G05D23/19—Control of temperature characterised by the use of electric means
    • G05D23/20—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature
    • G05D23/24—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature the sensing element having a resistance varying with temperature, e.g. a thermistor
    • 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
    • G03G15/20—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat
    • G03G15/2003—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat using heat

Definitions

  • ABSTRACT A temperature varying resistor is in one branch of a bridge circuit.
  • the voltage across the diagonal of the 30 l 1 Forelgn Application Emmy Data bridge controls the .heater cut in and cut off under Sept. 30, 1970 Germany ..P 20 48 076.6 normal operation,
  • the voltage across the temperature I varying resistor is applied to two threshold circuits and US. C.- .Q 19, the lamp motor and heater are disconnected from the 250/65 263/6 E power supply the ventilator remains connected, if the [5 1] Int. Cl. ..H05b 3/00 voltage across the temperature varying resistance is [58] Field of Search ..2l9/216, 481 -482,
  • the heater is thus controlled in such a manner that an excessively low operating temperature results, causing the reproductions to be insufficiently fixed.
  • :It is a further object of this invention to accomplish the above-mentioned objective with a minimum of equipment.
  • the present invention is a heater control circuit in electrostatic copying equipment which has heating means for providing the heat required for the fusing of the powder image on the transfer material. It comprises bridge circuit means having a first and second branch. A first and second bridge output terminal are located, respectively, in said first and second branch, said first branch further comprising means varying the signal at said first bridge output terminal as a function of temperature. Energizing means are provided for energizing.
  • First control means are connected to said bridge circuit means and connect and disconnect said heating means from said energizing means in dependence upon the difference and signal at said first and second bridge output terminal.
  • second control means are connected to said first bridge output terminal for disconnecting said heating means from said energizing means when said signal at said first bridge output terminal is outside of a predetermined signal range.
  • the heating means are disconnected from the energizing means whenever the resistance of the temperature varying resistance means is outside of the limits determined by the range of possible operating temperature of the equipment, that is, substantially between room temperature and a temperature lying somewhat above the highest permissible operating temperature.
  • the remainder of the copying apparatus, namely the lamp and the motor driving the drum carrying the transfer material is also deenergized.
  • the ventilator remains energized even after the first and second control means have operated.
  • the first and second control means comprise a relay whose contacts disconnect and connect the equipment from the energizing source upon receipt of corresponding operating signals.
  • This relay may be energized or deenergized (furnished operating signals) as a function of the state of a flip-flop (bistable means).
  • the flip-flop may, for example, be set by the output signal of two threshold circuits. Thereby the equipment will remain disconnected until the operator presses a switch provided for resetting of the flip-flop.
  • the first control means which function under normal conditions within the temperature varying resistor connect and disconnect only the heating coil from the energizing source.
  • the second control means which operate when a fault exists in the temperature varying resistance means disconnect also the motor driving the drum and the lamp.
  • the ventilator remains energized under all conditions so that any possible overheating of either the heating coil, the drum or-the transfer material will be removed as soon as possible.
  • FIGURE shows a preferred embodiment of the heater control arrangement of the present invention.
  • the bridge circuit means have a first branch comprising a resistance R, connected in series with the temperature varying resistance means, here a resistance labelled P,.
  • the first bridge circuit output terminal is labelled 25 and is the common point of resistor R, and P
  • the second branch of the bridge circuit means comprises a resistance R, series connected to a variable resistance R;,.
  • the common point of resistors R and R constitutes the second bridge output terminal and is connected to a line labelled 1 in the FIGURE.
  • the bridge is energized by a 24 volt source, one side of which is at ground potential.
  • the first control means comprise an amplifier 3 which may for example be a differential amplifier and which has an input connected to line 1 and a second input connected to terminal 25.
  • the output of amplifier 3 energizes first relay means, 4, whose contacts 5 serve to connect 1 and, 6, of heating coil 23 to energizing means, here an AC voltage of 220 volts.
  • the other side, 7, of the heating coil is directly connected to the 220 volt source.
  • the first bridge output terminal is further connected via line 2, 7 and 8 to the input of first threshold means, 10, and the lines 2, 7 and 9 to the input of second threshold means, 11.
  • the reference voltages to the threshold means are respectively provided by a variable DC voltage U and a variable DC voltage U respectively.
  • the output of the first threshold means is furnished on a line 13, that of the second threshold means on a line 14.
  • Lines 13 and 14 are connected in common to a line 12 which is in turn connected to-the input of a bistable stage 30.
  • the output of the bistable stage serves to control a relay 15 (second relay means).
  • Relay 15 in turn controls a switch 16 which, when closed connects motor 19, lamp 20 and heating coil 23 to the 22 0 volt source and when open disconnects thesefromsaid source.
  • the bistable circuit 30 is set by'the signal on the above-described line 12, then the reset input is activated by the depression of a key 21 which, when closed, connects said reset to a line 22 which in turn is connected to the 24 volt side of the battery energizing the bridge circuit.
  • the ventilator or fan 24 is directly connected to the 220 volt source without passing through the contacts of relay 15. This ventilator thus remains energized even after the remainder of the equipment is disconnected. The temperature of the equipment, if it has excessively increased, is thus brought to safe values as soon as possible.
  • the above-described equipment operates as follows:
  • the bridge circuit is adjusted via resistance 3 so that no voltage exists between the first and second bridge output terminals (lines 1, 2) when the resistance of the temperature varying resistor P, corresponds to. the desired operating temperature of heating coil 23.
  • amplifier 3 energizes relay 4 causing contacts 5 to be closed.
  • the heater coil is now energized and continues to operate until the upper temperature limit of the desired operating temperature is reached and the resistance of resistor P, exceeds the value for which the bridge was balanced. If a malfunction develops in resistor P, its resistance value and therefore the voltage across it exceeds the voltage appearing across it under normal operating conditions.
  • the voltage across the resistor will decrease to substantially zero in case of a short-circuit, thereby being less than the voltage U, constituting the reference voltage for the first threshold circuit 10.
  • a signal will then appear on line 13 which will set flip-flop 30, operating relay 15 to open contact 16.
  • the voltage at the first bridge output terminal will increase beyond the second reference voltage U; thereby causing a signal to appear on line 14 at the output of the second threshold means.
  • the signal at the output of the second threshold means will operate to open contacts 16 in exactly the same manner as the signal appearing at the output of the first threshold means.
  • a-signal at the output of either the first or second threshold means will cause the lamp, motor and heater coil to be de-energized while the ventilator 24 continues to operate.
  • the operator pushes key 21 causing flip-flop to be reset, operating relay 15 to close contact 16 and the normal operation of the equipment continues.
  • a control arrangement for said heating means comprising, in combination, bridge circuit means having a first and second branch and a first and second bridge output terminal in said first and second branch respectively, said first branch comprising means varying the signal at said first bridge output terminal as a function of temperature; energizing means for energizing said heating means; first control means connected between said first and second bridge output terminal for connecting said heating means to said energizing means and disconnecting said heating means from said energizing means in dependence upon the difference in signal at said first and second bridge output terminal; and second control means connected to said first bridge output terminal for disconnecting said heating means from said energizing means when said signal at said first bridge output terminal is outside of a predetermined signal range.
  • Electrostatic copying means as set forth in claim 1, wherein said means varying said signal at said first bridge output terminal as a function of temperature comprise temperature varying resistance means.
  • Electrostatic copying means as set forth in claim 2, wherein said first control means comprise amplifier means, and first relay means having a coil connected to the output of said amplifier means and first relay contact means interconnected between said heating means and said energizing means.
  • Electrostatic copying means as set forth in claim 3, wherein said amplifier means comprise differential amplifier means.
  • Electrostatic copying means as set forth in claim 1, wherein said second control means comprise first and second threshold means, each having an input connected to said first bridge output terminal, said first and second threshold means respectively furnishing a first and second threshold output signal in response to a signal at said first bridge output terminal respectively exceeding a predetermined maximum signal and less than a predetermined minimum signal.
  • Electrostatic copying means as set forth in claim 5, wherein said second control means further comprise bistable means connected to said first and second threshold means for furnish a bistable output signal in response to' said first or second output signal; and second relay means disconnecting said heating means

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Fixing For Electrophotography (AREA)
  • Control Of Temperature (AREA)
  • Control Of Resistance Heating (AREA)
US182986A 1970-09-30 1971-09-23 Electronic copying equipment with controlled heater Expired - Lifetime US3705289A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19702048076 DE2048076C3 (de) 1970-09-30 Elektrostatisches Kopiergerat

Publications (1)

Publication Number Publication Date
US3705289A true US3705289A (en) 1972-12-05

Family

ID=5783808

Family Applications (1)

Application Number Title Priority Date Filing Date
US182986A Expired - Lifetime US3705289A (en) 1970-09-30 1971-09-23 Electronic copying equipment with controlled heater

Country Status (6)

Country Link
US (1) US3705289A (enrdf_load_stackoverflow)
JP (1) JPS514860B1 (enrdf_load_stackoverflow)
BE (1) BE772962A (enrdf_load_stackoverflow)
FR (1) FR2108275A5 (enrdf_load_stackoverflow)
GB (1) GB1369631A (enrdf_load_stackoverflow)
IT (1) IT939482B (enrdf_load_stackoverflow)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3778222A (en) * 1972-09-18 1973-12-11 Xerox Corp Fire prevention apparatus
US3795787A (en) * 1971-08-19 1974-03-05 T Nogaito Heat fixing system in an electrophotographic copying machine having a temperature control device
US4109134A (en) * 1975-08-08 1978-08-22 Oce-Van Der Grinten N.V. Power control circuit and electro(photo)graphic apparatus employing same
US4118178A (en) * 1977-07-21 1978-10-03 Pitney-Bowes, Inc. Xerographic fusing apparatus
US4318612A (en) * 1980-07-10 1982-03-09 International Business Machines Corporation Hot roll fuser temperature control
EP0074840A3 (en) * 1981-09-16 1983-04-20 Nordson Corporation Control circuit
US4565455A (en) * 1983-01-21 1986-01-21 Hotfoil Limited Heat regulating sensor tape
US5300981A (en) * 1990-07-27 1994-04-05 Tokyo Electric Co., Ltd. Electrophotographic printing apparatus with fire prevention
US5369246A (en) * 1993-08-16 1994-11-29 General Binding Corporation Temperature control for laminator
US20140356013A1 (en) * 2013-05-31 2014-12-04 Kyocera Document Solutions Inc. Image forming apparatus and electric charge eliminating method

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2262691C3 (de) * 1972-12-21 1982-02-11 Vdo Adolf Schindling Ag, 6000 Frankfurt Elektronischer Temperaturschalter
US4056708A (en) * 1975-07-22 1977-11-01 Baxter Travenol Laboratories, Inc. Digital temperature controller
US5520327A (en) * 1994-09-23 1996-05-28 Carrier Corporation Electronic thermostat having safety feature
FR2727533B1 (fr) * 1994-11-28 1997-01-17 Seb Sa Dispositif de detection et de securite pour appareil de cuisson

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3505497A (en) * 1966-04-28 1970-04-07 Arlside Ltd Reprographic apparatus heater unit control

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS443031Y1 (enrdf_load_stackoverflow) * 1966-04-19 1969-02-04

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3505497A (en) * 1966-04-28 1970-04-07 Arlside Ltd Reprographic apparatus heater unit control

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3795787A (en) * 1971-08-19 1974-03-05 T Nogaito Heat fixing system in an electrophotographic copying machine having a temperature control device
US3778222A (en) * 1972-09-18 1973-12-11 Xerox Corp Fire prevention apparatus
US4109134A (en) * 1975-08-08 1978-08-22 Oce-Van Der Grinten N.V. Power control circuit and electro(photo)graphic apparatus employing same
US4118178A (en) * 1977-07-21 1978-10-03 Pitney-Bowes, Inc. Xerographic fusing apparatus
US4318612A (en) * 1980-07-10 1982-03-09 International Business Machines Corporation Hot roll fuser temperature control
EP0074840A3 (en) * 1981-09-16 1983-04-20 Nordson Corporation Control circuit
US4565455A (en) * 1983-01-21 1986-01-21 Hotfoil Limited Heat regulating sensor tape
US5300981A (en) * 1990-07-27 1994-04-05 Tokyo Electric Co., Ltd. Electrophotographic printing apparatus with fire prevention
US5369246A (en) * 1993-08-16 1994-11-29 General Binding Corporation Temperature control for laminator
US20140356013A1 (en) * 2013-05-31 2014-12-04 Kyocera Document Solutions Inc. Image forming apparatus and electric charge eliminating method
US9213298B2 (en) * 2013-05-31 2015-12-15 Kyocera Document Solutions Inc. Image forming apparatus and electric charge eliminating method

Also Published As

Publication number Publication date
BE772962A (nl) 1972-03-23
FR2108275A5 (enrdf_load_stackoverflow) 1972-05-19
IT939482B (it) 1973-02-10
DE2048076B2 (de) 1977-02-10
DE2048076A1 (de) 1972-04-06
JPS514860B1 (enrdf_load_stackoverflow) 1976-02-16
GB1369631A (en) 1974-10-09

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