Image forming apparatus having a processor circuit that controls an amount of discharge of ultra fine particles discharged from the image forming apparatus, and related method

An image forming apparatus comprising:

• (A) a fixing device configured to fix, by adding heat and pressure to a toner image formed on a sheet, the toner image to the sheet;
• (B) a temperature sensor configured to detect a temperature of an end of the fixing device in a direction perpendicular to a sheet conveyance direction;
• (C) a cooling fan configured to supply air to the end of the fixing device to cool the end of the fixing device;
• (D) a shutter provided at an exit of the cooling fan, and configured to be opened and closed;
• and
• (E) a processor circuit configured:
• (a) to control a cooling level by the cooling fan in accordance with the temperature of the end of the fixing device detected by the temperature sensor;
• (b) to predict an ambient temperature of the fixing device based on the cooling level, wherein the processor circuit predicts the ambient temperature at regular intervals, and is configured to predict the ambient temperature of the fixing device by multiplying a temperature coefficient by a difference between a convergence temperature, obtained based on an opening amount of the shutter, and a predicted ambient temperature for a previous interval, which is a set initial ambient temperature and is replaced by the predicted ambient temperature for each subsequent interval, and then adding the predicted ambient temperature for the previous interval;
• (c) to predict, based on the ambient temperature, a discharge amount of ultra fine particles that are discharged from the image forming apparatus;
• and
• (d) to control an image forming operation by the image forming apparatus such that the discharge amount of ultra fine particles is reduced in accordance with the discharge amount predicted by the processor circuit.

An image forming apparatus comprising:

• (A) a fixing device configured to fix, by adding heat and pressure to a toner image formed on a sheet, the toner image to the sheet;
• (B) a temperature sensor configured to detect a temperature of an end of the fixing device in a direction perpendicular to a sheet conveyance direction;
• (C) a cooling fan configured to supply air to the end of the fixing device to cool the end of the fixing device;
• and
• (D) a processor circuit configured:
• (a) to control a cooling level by the cooling fan in accordance with the temperature of the end of the fixing device detected by the temperature sensor;
• (b) to obtain an ambient temperature of the fixing device based on the cooling level;
• (c) to predict, based on the ambient temperature, a discharge amount of ultra fine particles that are discharged from the image forming apparatus;
• and
• (d) to control an image forming operation by the image forming apparatus such that the discharge amount of ultra fine particles is reduced in accordance with the discharge amount predicted by the processor circuit,
• wherein the processor circuit is configured to operate in a first mode, in which the discharge amount of ultra fine particles is reduced by controlling a conveyance speed of a sheet, and a second mode, in which the discharge amount of ultra fine particles is reduced by controlling a conveyance interval of two adjacent sheets, and, based on at least one of the ambient temperature and the discharge amount of ultra fine particles predicted by the processor circuit, the processor circuit selects one of the first mode and the second mode.

A method of controlling an image forming apparatus comprising a fixing device configured to fix, by adding heat and pressure to a toner image formed on a sheet, the toner image to the sheet, a temperature sensor configured to detect a temperature of an end of the fixing device in a direction perpendicular to a sheet conveyance direction, a cooling fan configured to supply air to the end of the fixing device to cool the end of the fixing device, and a shutter provided at an exit of the cooling fan, the shutter being configured to be opened and closed, the method comprising:

• controlling a cooling level by the cooling fan in accordance with the temperature of the end of the fixing device detected by the temperature sensor;
• predicting, based on at least one parameter depending on the cooling level, a discharge amount of ultra fine particles that are discharged from the image forming apparatus, thereby producing a predicted discharge amount;
• and
• controlling an image forming operation by the image forming apparatus such that the discharge amount of ultra fine particles is reduced in accordance with the predicted discharge amount,
• wherein the predicting comprises predicting the discharge amount of ultra fine particles by using an air flow amount of the cooling fan and an opening amount of the shutter as parameters depending on the cooling level.