Image forming apparatus and belt unit therefor, and image forming system

An image forming apparatus comprising:

• at least one image bearing member on which a visible image is formed;
• an intermediary transfer member onto which visible images of different colors formed on the at least one image bearing member are transferred to be superimposed one upon another, thereby forming a first image thereupon;
• and
• an installing part provided in a main body housing of the apparatus and configured such that any of at least two intermediary image bearing members different in size is easily installed or removed, wherein each of the intermediary image bearing members different in size is configured such that when installed in the installing part of the main body housing of the apparatus, the intermediary image bearing members different in size will have the first image transferred thereupon,
• wherein the image forming apparatus is configured such that when the any of at least two intermediary image bearing members different in size is installed in the installing part of the main body housing of the apparatus, the first image on the installed any of at least two intermediary image bearing members is transferred onto one side of a recording medium and a second image formed on the installed any of at least two intermediary image bearing members different in size member by other visible images subsequently transferred from the at least one image bearing member being superimposed one upon another is transferred onto the other side of the recording medium.

An image forming apparatus comprising:

• at least one image bearing member on which a visible image is formed;
• an intermediary transfer member onto which visible images of different colors formed on the at least one image bearing member are transferred to be superimposed one upon another, thereby forming a first image thereupon;
• and
• an installing part provided in a main body housing of the apparatus and configured to easily install or remove either of a transfer device configured such that when installed in the installing part of the main body housing of the apparatus, the first image formed on the intermediary transfer member is transferred onto a recording medium, or an intermediary image bearing member configured such that when installed in the installing part of the main body housing of the apparatus, the first image formed on the intermediary transfer member is transferred thereupon,
• wherein the image forming apparatus is configured such that when the intermediary image bearing member is installed in the installing part of the main body housing of the apparatus, the first image transferred onto the intermediary image bearing member from the intermediary transfer member is transferred onto a first side of the recording medium and a second image formed on the intermediary transfer member by other visible images of different colors, subsequently transferred from the at least one image bearing member being superimposed one upon another, is transferred onto a second side of the recording medium.

An image forming apparatus comprising:

• at least one image bearing member on which a visible image is formed;
• and
• an installing part provided in a main body housing of the apparatus and configured to easily install or remove either of a transfer device configured such that when installed in the installing part of the main body housing of the apparatus, the visible image formed on the at least one image bearing member is transferred onto a recording medium, or an intermediary image bearing member configured such that when installed in the installing part of the main body housing of the apparatus, visible images formed on the at least one image bearing member are transferred thereon to be superimposed one upon another, thereby forming a first image thereupon,
• wherein the image forming apparatus is configured such that when the intermediary image bearing member is installed in the installing part of the main body housing of the apparatus, the first image on the intermediary image bearing member is transferred onto a first side of the recording medium and a second image formed by other visible images subsequently formed on the at least one image bearing member is transferred onto a second side of the recording medium.