Image forming apparatus determining order for starting first motor and second motor by using temperature of fixing device

An image forming apparatus comprising:

• a polygon mirror configured to reflect light emitted from a light source;
• a first motor configured to rotary drive the polygon mirror;
• a photosensitive member having an outer peripheral surface to which the light reflected by the polygon mirror emits;
• a fixing device having a heater, a first member, and a second member, wherein the first member and the second member are configured to convey a sheet interposed therebetween, the fixing device being located downstream of the photosensitive member in a conveying direction of the sheet;
• a second motor configured to rotary drive the first member;
• a sensor configured to output a signal depending on temperature of the fixing device;
• and
• a controller operatively connected to the first motor, the second motor, and the heater, the controller being configured to:
• start the heater to heat up in response to a print command;
• estimate a first time period starting at a timing when the heater starts heating up and ending at an estimated timing when the second motor starts rotation;
• in a first case where the first time period is longer than a second time period, set a first-motor-start timing prior to a second-motor-start timing, wherein the first-motor-start timing is a timing at which the first motor starts rotation and the second-motor-start timing is a timing at which the second motor starts rotation, the second time period including an estimated preparation time period for the first motor from a rotation start timing of the first motor to a timing at which rotation of the first motor reaches a first target rotational speed, and
• in a second case where the first time period is shorter than the second time period, set the second-motor-start timing prior to the first-motor-start timing.

A non-transitory computer readable storage medium storing a set of program instructions installed on and executed by a computer for controlling an image forming apparatus including:

• a polygon mirror configured to reflect light emitted from a light source;
• a first motor configured to rotary drive the polygon mirror;
• a photosensitive member having an outer peripheral surface to which the light reflected by the polygon mirror emits;
• a fixing device having a heater, a first member, and a second member, wherein the first member and the second member are configured to convey a sheet interposed therebetween, the fixing device being located downstream of the photosensitive member in a conveying direction of the sheet;
• a second motor configured to rotary drive the first member;
• a conveyance device having a roller configured to convey the sheet;
• a sensor configured to output a signal depending on temperature of the fixing device;
• and a controller operatively connected to the first motor, the second motor, the heater, and the conveyance device, the set of program instructions comprising:
• starting the heater to heat up in response to a print command;
• in a first case where the signal indicates that the temperature of the fixing device at a timing of reception of the print command is lower than a first threshold value, starting rotating the first motor before the temperature of the fixing device reaches a target temperature, and subsequently starting rotating the second motor before the conveying device conveys the sheet according to the received print command wherein the first threshold value is lower than the target temperature;
• and
• in a second case where the signal indicates that the temperature of the fixing device at the timing of reception of the print command is higher the first threshold value, starting rotating the second motor before the temperature of the fixing device reaches the target temperature, and subsequently starting rotating the first motor before the conveying device conveys the sheet according to the received print command

A non-transitory computer readable storage medium storing a set of program instructions installed on and executed by a computer for controlling an image forming apparatus including:

• a polygon mirror configured to reflect light emitted from a light source;
• a first motor configured to rotary drive the polygon mirror;
• a photosensitive member having an outer peripheral surface to which the light reflected by the polygon mirror emits;
• a fixing device having a heater, a first member, and a second member, wherein the first member and the second member are configured to convey a sheet interposed therebetween, the fixing device being located downstream of the photosensitive member in a conveying direction of the sheet;
• a second motor configured to rotary drive the first member;
• a sensor configured to output a signal depending on temperature of the fixing device;
• and a controller operatively connected to the first motor, the second motor, and the heater, the set of program instructions comprising:
• starting the heater to heat up in response to a print command;
• estimating a first time period starting at a timing when the heater starts heating up and ending at an estimated timing when the second motor starts rotation;
• in a first case where the first time period is longer than a second time period, setting a first-motor-start timing prior to a second-motor-start timing, wherein the first-motor-start timing is a timing at which the first motor starts rotation and the second-motor-start timing is a timing at which the second motor starts rotation, the second time period including an estimated preparation time period for the first motor from a rotation start timing of the first motor to a timing at which rotation of the first motor reaches a first target rotational speed, and
• in a second case where the first time period is shorter than the second time period, setting the second-motor-start timing prior to the first-motor-start timing.