Image forming apparatus

An image forming apparatus, comprising:

• an optical scanning device including
• a light source unit that is configured to emit a laser beam,
• a polygonal mirror that is configured to reflect the emitted laser beam from the light source unit by being rotated about a rotation axis extending in an upper-and-lower direction, whereby a peripheral surface of an image bearing member is scanned in a main scanning direction,
• a scanning lens that is configured to form the laser beam reflected by the polygonal mirror into an image on the peripheral surface of the image bearing member,
• a casing that is configured to house
• the light source unit,
• the polygonal mirror, and
• the scanning lens, and
• a temperature sensor that is configured to detect a temperature in the casing;
• the image bearing member that includes an at least one image bearing member having a surface on which a photosensitive layer is formed;
• a charging device that is configured to charge the image bearing member with a predetermined surface potential;
• a developing device
• that is arranged to face the image bearing member,
• that includes a developer carrying member which is configured to carry a developer, and
• that is configured to form a toner image by applying predetermined developing voltage to the developer carrying member to cause a toner to adhere to an electrostatic latent image formed on the image bearing member;
• and
• a control unit that is configured to control
• the optical scanning device, and
• the developing device,
• the temperature sensor detecting a temperature of the developing device,
• the control unit
• controlling the optical scanning device on a basis of the temperature in the casing, the temperature in the casing being detected by the temperature sensor, and
• controlling the developing device on a basis of the temperature of the developing device, the temperature of the developing device being detected by the temperature sensor,
• the image forming apparatus further comprising:
• an IC driver that is configured to control the light source unit;
• and
• a circuit board
• to which the IC driver is mounted and
• which is housed in the casing,
• wherein the temperature sensor is mounted to the circuit board, and
• wherein, on the circuit board, the temperature sensor is arranged on a side that is opposite to a side where the IC driver is present with an external connection terminal interposed between the temperature sensor and the IC driver.