IMAGE FORMING APPARATUS

• US 20140126922A1
• Filed: 05/15/2013
• Published: 05/08/2014
• Est. Priority Date: 11/02/2012
• Status: Active Grant

• Current Assignee: Fujifilm Business Innovation Corp. (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Xerox Company Limited (Fujifilm Holdings Corporation)
• Inventors: SATO, Nobuyuki, IMAHORI, Kazuki
• Granted Patent: US 9,304,453 B2
• Time in Patent Office: Days
• US Class Current: 399/33
• CPC Class Codes: G03G 15/2039 with means for controlling the fixing temperature

Abstract

An image forming apparatus includes a heating element that generates heat, a temperature detector that detects a temperature of the heating element, a resistor that divides a detection result of the temperature detector and a predetermined reference voltage, a disconnection detector that detects a disconnection of the temperature detector, a converter that converts the divided voltage value into a digital signal and outputs the digital signal to a controller, a comparing unit that inverts its output on the basis of a predetermined threshold, a delay circuit that delays an increase in an output voltage of the comparing unit, a discharge circuit that quickly discharges the output voltage of the comparing unit, a latch circuit connected to an output of the discharge circuit, and a power supply path connecting and disconnecting unit that is connected to the latch circuit and connects and disconnects a power supply path to the heating element.

Claims

1. An image forming apparatus comprising:

a heating element that generates heat when a current is applied thereto;

a temperature detector that is disposed in the vicinity of the heating element and detects a temperature of the heating element;

a resistor that divides a detection result of the temperature detector and a predetermined reference voltage;

a disconnection detector that is connected in parallel to the resistor, and detects a disconnection of the temperature detector;

a converter that converts the divided voltage value into a digital signal and outputs the digital signal to a controller;

a comparing unit that inverts an output thereof on the basis of a predetermined threshold;

a delay circuit that delays an increase in an output voltage of the comparing unit;

a discharge circuit that quickly discharges the output voltage of the comparing unit;

a latch circuit that includes a flip-flop connected to an output of the discharge circuit; and

a power supply path connecting and disconnecting unit that is connected to the latch circuit, and connects and disconnects a power supply path to the heating element.

2. The image forming apparatus according to claim 1, wherein a delay time of the delay circuit and the discharge circuit is greater than time taken to switch from temperature detection to disconnection detection.

3. The image forming apparatus according to claim 1, wherein the delay circuit and the discharge circuit include a capacitor and a resistor.

4. The image forming apparatus according to claim 1, wherein the delay circuit and the discharge circuit include a reset circuit.