Heater with a protective layer continuously covering a heat generating member and having a pluralipfy of recesses provided at intervals on a substrate. heating device and image forming apparatus

A heater comprising:

• a substrate;
• a heat generating member provided on the substrate;
• and
• a protective layer configured to continuously cover a region in the substrate where the heat generating member is provided and on a surface of which a plurality of recesses are formed,
• wherein when a direction of a longer side in a face of the substrate on which the heat generating member is provided is defined as a longitudinal direction, a direction perpendicular to the longitudinal direction in the face is defined as a short direction, and a direction perpendicular to the longitudinal direction and the short direction is defined as a thickness direction, a first region where the heat generating member is provided and a second region where the plurality of recesses are formed are not overlapped with each other as the protective layer is viewed in the thickness direction, and
• wherein the plurality of recesses
• have a predetermined width, a predetermined length, and a predetermined depth, respectively,
• are arranged at predetermined intervals in the longitudinal direction at positions not overlapped with the heat generating member in the short direction, and
• are formed in an inclined line shape with respect to the short direction,
• wherein one recess of the plurality of recesses and a recess adjacent to the one recess are overlapped with each other in the longitudinal direction,
• wherein the heat generating member includes two heat generating portions spaced apart in the short direction, and
• wherein the plurality of recesses are formed in a region between the two heat generating portions in the short direction.