Sleeve, developer carrying member, and developing device

A developer carrying member comprising:

• a rotatable sleeve;
• and
• a magnet provided inside the sleeve,
• wherein the sleeve includes a developer carrying and conveying portion which is configured to carry and convey a developer containing toner and a carrier to a developing position and which includes a groove portion which is a portion where a groove is formed and a non-groove portion where the groove is not formed,
• wherein in a case where a depth of the groove is D, a radius of the carrier is R, and a width of the groove in a rotational direction of the sleeve is W, D>R and W>2R are satisfied, and
• wherein the non-groove portion includes a chromium layer on an outer surface of the sleeve, and the chromium layer is 1 μm or more and 5 μm or less in thickness.

A developer carrying member comprising:

• a rotatable sleeve;
• and
• a magnet provided inside the sleeve,
• wherein the sleeve includes a developer carrying and conveying portion which is configured to carry and convey a developer containing toner and a carrier to a developing position and which includes a groove portion which is a portion where a groove is formed and a non-groove portion where the groove is not formed,
• wherein in a case where a depth of the groove is D, a radius of the carrier is R, and a width of the groove in a rotational direction of the sleeve is W, D>R and W>2R are satisfied, and
• wherein each of the groove portion and the non-groove portion includes a chromium layer on an outer surface of the sleeve.

A developing device comprising:

• a developing container configured to accommodate a developer containing toner and a carrier;
• and
• a developer carrying member including a rotatable sleeve and a magnet provided inside the sleeve,
• wherein the sleeve includes a developer carrying and conveying portion which is configured to carry and convey the developer to a developing position and which includes a groove portion which is a portion where a groove is formed and a non-groove portion where the groove is not formed,
• wherein in a case where a depth of the groove is D, a radius of the carrier is R, and a width of the groove in a rotational direction of the sleeve is W, D>R and W>2R are satisfied, and
• wherein the non-groove portion includes a chromium layer on an outer surface of the sleeve, and the chromium layer is 1 μm or more and 5 μm or less in thickness.

A developing device comprising:

• a developing container configured to accommodate a developer containing toner and a carrier;
• and
• a developer carrying member including a rotatable sleeve and a magnet provided inside the sleeve,
• wherein the sleeve includes a developer carrying and conveying portion which is configured to carry and convey the developer to a developing position and which includes a groove portion which is a portion where a groove is formed and a non-groove portion where the groove is not formed,
• wherein in a case where a depth of the groove is D, a radius of the carrier is R, and a width of the groove in a rotational direction of the sleeve is W, D>R and W>2R are satisfied, and
• wherein each of the groove portion and the non-groove portion includes a chromium layer on an outer surface of the sleeve.