EP0251725A2
Expired / Lapsed
EP
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Method of and apparatus for preventing overheating of heating element
Assignee: Oki Electric Industry Co Ltd
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Filing: 1987-06-26
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Granted: —
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Expires: 2007-06-26
Abstract
Abstract An element which in use emits heat, e.g. a line feed motor (LF) for a printer, is prevented from overheating. Normally, the printer increments the LF motor line by line at a rate which does not overheat the LF motor. However, if the motor is driven substantially continuously, overheating may occur. To prevent this, a first timer TM 1 is set to count a first time interval ti. The number of line feed increments is counted during t 1 to provide a first heat release signal P indicative of the heat generated by the motor. If P exceeds a prescribed value (i.e. if overheating occurs) a timer TM 2 is started. During the time that TM 2 is operative, the LF motor can only be incremented at a slower rate that would be correspondingly possible during the period ti, for causing cooling of the motor. A second heat release signal P is determined for the period t 2 of the time TM 2 . If the second heat release signal is less than a prescribed value the motor returns to normal operation under the control of timer TM 1 ; otherwise it is controlled for a further period under timer TM 2 to promote cooling.
Inventors
- 👤 Toshikazu Oki Electric Industry Co. Ltd. Itoh
- 👤 Toshiroh Oki Electric Industry Co. Ltd. Suemune
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 10:00
CPC Classifications
B; B41; B41J; B41J29/00; B41J29/38; B41J29/377
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
169 words
(1) A method of controlling operation of an element which in use emits heat, characterised by the steps of: providing a first heat release signal indicative of the amount of heat generated by the element as a result of operation thereof during a first period; determining whether said first heat release signal is in a prescribed relationship to a reference value therefor; controlling operation of said element for a second period such that it can only be operated at a slower rate than would be correspondingly permissible during the first period, if said first heat release signal is not in said prescribed relationship with said reference value; providing a second heat release signal indicative of the amount of heat generated by the element during the second period; determining whether said second heat release signal assumes a desired relationship with a reference value therefor; and carrying out a said controlling operation at a said slower rate for a further period unless said second heat release signal assumes said desired relationship.
Claim 2
Dependent Claim
236 words
(2) A method of preventing overheating of a heating element comprising the steps of: (a) setting the total of a heat release value to "0" after powering a first timer to start it, said first timer (TM 1 ) serving to count a prescribed first time interval (ti); (b) subtracting an allowable heat release value of the heating element for the first time interval (P i ) from the total of the heat release value (P) as said first timer counts the prescribed time and setting the total of the heat release value to "0" when the remainder of said subtraction is "0" or a negative value, while starting a second timer when said remainder is any value other than "0" of negative values: (c) subtracting an allowable heat release value of the heating element for a prescribed second time interval (t 2 ) from the total of the heat release value when said second timer (TM 2 ) counts the prescribed time, and setting the total of the heat release value to "0" when the remainder of said subtraction is "0" or a negative value to start said first timer, while starting said second timer (TM 2 ) when said remainder is any value other than "0" or negative values; and (d) providing a prescribed pause time before driving the heating element only during the time interval counted by said second timer (TM 2 ).
Claim 3
Dependent Claim
234 words
(3) An apparatus for preventing overheating of a heating element comprising: (a) a first timer (TMi) for counting a prescribed first time interval (ti); (b) a second timer (TM 2 ) for counting a prescribed second time interval (t 2 ); (c) evaluation means for evaluating a heat release value of the heating element within said prescribed time counted by any of said first and second timers (TM 1 , TM 2 ),on the basis of the number of times of driving of the heating element whilst said both timers (TM 1 , TM 2 ) are respectively counting said prescribed times and further adding the total of the heat release value up to that time to said heat release value evaluated previously to evaluate the total of a new heat release value; (d) first means for subtracting an allowable heat release value (P i ) of the heating element for said first time interval from the total of the heat release value (P) and storing the remainder (P-Pi) of said subtraction as the total of a new heat release value; and (e) second means for subtracting an allowable heat release value (P 2 ) of the heating element for said second time interval (t 2 ) from the total of the heat release value and storing the remainder (P-P 2 ) of the subtraction as the total of a new heat release value.
Claim 4
Dependent Claim
28 words
(4) A method of preventing overheating of a heating element according to claim 1, wherein said heating element is a line feed motor for use in a printer.
Claim 5
Dependent Claim
28 words
(5) An apparatus for preventing overheating of a heating element according to claim 2, wherein said heating element is a line feed motor for use in a printer.
Claim 6
Dependent Claim
32 words
(6) An apparatus for preventing overheating of a heating element according to claim 2, wherein said evaluation means for evaluating a heat release value of the heating element is a CPU (1).
Claim 7
Dependent Claim
22 words
(7) An apparatus for preventing overheating of a heating element according to claim 2, wherein said first means is a register (Pi).
Claim 8
Dependent Claim
24 words
(8) An apparatus for preventing overheating of a heating element according to claim 2, wherein said second means is a register (P 2 ).
Claim 9
Dependent Claim
21 words
(9) An apparatus for preventing overheating of a heating element according to claim 2, wherein said apparatus further includes a ROM
Claim 10
Dependent Claim
92 words
(2) for storing a program for execution of the present method of preventing overheating of a heating element and for storing fixed data for use in the execution of the present method, a RAM (3) for storing any received data in need of the execution of the present method of preventing overheating of a heating element and received from the outside, an I/O driver (5) for driving the heating element, etc., in conformity with an instruction from said CPU (1), and a bus line for connection said CPU (1), ROM (2), RAM
Claim 11
Dependent Claim
15 words
(3), timers (TM 1 , TM 2 ), and I/O driver (5) in this order.
References Cited (Backward Citations)
No citation records indexed.
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