Fan Controller and Image Forming Apparatus

Abstract

A fan controller and an image forming apparatus are provided. The fan controller includes a rotational frequency instructing unit configured to output driving instructions to a fan driving unit that is configured to control a rotational frequency of a fan, the driving instructions including a target value of the rotational frequency of the fan; a rotational frequency detection unit configured to detect an actual measurement value of the rotational frequency of the fan; a storage unit configured to store consecutively at given time intervals a plurality of parameters indicating a correspondence relationship between the driving instructions output by the rotation frequency instructing unit and the rotational frequency detected by the rotational frequency detection unit; and a notification unit configured to notify a condition of the fan on the basis of the plurality of parameters. The image forming apparatus includes a fan, a fan driver and the fan controller.

1 . A fan controller comprising:
 a rotational frequency instructing unit configured to output driving instructions to a fan driving unit that is configured to control a rotational frequency of a fan, the driving instructions comprising a target value of the rotational frequency of the fan;   a rotational frequency detection unit configured to detect an actual measurement value of the rotational frequency of the fan;   a storage unit configured to store consecutively at given time intervals a plurality of parameters indicating a correspondence relationship between the driving instructions output by the rotation frequency instructing unit and the rotational frequency detected by the rotational frequency detection unit; and   a notification unit configured to notify a condition of the fan on the basis of the plurality of parameters.   
   
   
       2 . The fan controller according to  claim 1 , wherein when each of a given number of consecutively stored parameters of the plurality of parameters indicates that the actual measurement values are greater than the target value, the notification unit notifies an error corresponding to the condition thereof. 
   
   
       3 . The fan controller according to  claim 2 , wherein when each of a given number of consecutively stored parameters of the plurality of parameters indicates that the actual measurement values are less than the target value, the notification unit notifies an error corresponding to the condition thereof. 
   
   
       4 . The fan controller according to  claim 1 , wherein when each of a given number of consecutively stored parameters of the plurality of parameters indicate that the actual measurement values are less than the target value, the notification unit notifies an error corresponding to the condition thereof. 
   
   
       5 . The fan controller according to  claim 1 , wherein when one parameter of the plurality of parameters indicates that the actual measurement value is lower than the target value and also when a value of the one parameter indicates that a difference between the actual measurement value and the target value is greater than a threshold value, the notification unit notifies an error corresponding to the condition thereof. 
   
   
       6 . The fan controller according to  claim 1 , wherein the driving instructions are a voltage applied to the fan driving unit, and
 the parameter is a value obtained by dividing the actual measurement value by the voltage.   
   
   
       7 . The fan controller according to  claim 1 , wherein the driving instructions are a pulse width modulated (PWM) signal, and
 the parameter is a value obtained by dividing the actual measurement value by a duty ratio of the PWM signal.   
   
   
       8 . An image forming apparatus comprising:
 a fan;   a fan driver configured to control a rotation frequency of the fan; and   a fan controller comprising:
 a rotational frequency instructing unit which outputs driving instructions to the fan driver, the driving instructions comprising a target value of the rotational frequency of the fan; 
 a frequency detector which detects an actual measurement value of the rotational frequency of the fan; 
 a memory which consecutively at given time intervals stores a plurality of parameters indicating a correspondence relationship between the driving instructions output by the rotational frequency instructing unit and the rotational frequency detected by the frequency detector; and 
 a notification unit which indicates a condition of the fan on the basis of the plurality of parameters. 
   
   
   
       9 . A fan controller comprising:
 an integrated circuit comprising:
 a rotational frequency instructing circuit which outputs driving instructions to a fan driver that is configured to control a rotational frequency of a fan, the driving instructions comprising a target value of the rotational frequency of the fan; 
 a frequency detector which detects an actual measurement value of the rotational frequency of the fan; 
 a memory circuit which consecutively at given time intervals stores a plurality of parameters indicating a relationship between the driving instructions output by the rotational frequency instructing circuit and the rotational frequency detected by the frequency detector; and 
 a notification circuit which indicates a condition of the fan on the basis of the plurality of parameters. 
   
   
   
       10 . The fan controller according to  claim 9 , wherein the fan driver comprises an external driving circuit which comprises a high voltage output circuit, a medium voltage output circuit, and a low voltage output circuit,
 wherein the rotational frequency instructing circuit is coupled to the external driving circuit and controls the external driving circuit to output a high voltage, a medium voltage, or a low voltage, as the driving instructions, to the fan based on an output from the fan driver circuit.   
   
   
       11 . The fan controller according to  claim 9 , wherein the driving instructions comprise a pulse width modulated signal. 
   
   
       12 . The fan controller according to  claim 11 , further comprising a controller,
 wherein when a value of the plurality of parameters exceeds a first threshold range, the controller controls the notification circuit to indicate a first error and halts a rotation of the fan,   when consecutive values of the plurality of parameters are within the first threshold range but exceed an upper limit of the target value for a given number of times, the controller controls the notification circuit to indicate a second error and halts the rotation of the fan, and   when consecutive values of the plurality of parameters are within the first threshold range but decrease below a lower limit of the target value for a given number of times, the controller controls the notification circuit to indicate a third error and halts a rotation of the fan.