Image forming apparatus

An image forming apparatus comprising:

• an image forming portion configured to form a toner image on a recording material;
• a fixing portion including a tubular film and a heating portion configured to heat the film, configured to form a nip portion to nip the recording material, and configured to fix the toner image to the recording material by heating the toner image with the film;
• a housing configured to accommodate the image forming portion and the fixing portion and having an opening portion through which an outside of the housing and an inside of the housing communicate with each other, the opening portion being positioned above the nip portion in a vertical direction;
• and
• a filter covering the opening portion,
• wherein a maximum particle diameter of particles capable of passing through the filter is smaller than a thickness of the film.

An image forming apparatus comprising:

• an image forming portion including a photosensitive member and an intermediate transfer belt and configured to transfer a toner image formed on the photosensitive member onto the intermediate transfer belt through primary transfer and then transfer the toner image from the intermediate transfer belt onto a recording material through secondary transfer;
• a fixing portion configured to form a nip portion to nip the recording material, and configured to fix the toner image to the recording material by heating the toner image while conveying the recording material with the nip portion;
• a housing configured to accommodate the image forming portion and the fixing portion and having an opening portion through which an outside of the housing and an inside of the housing communicate with each other, the opening portion being positioned above the nip portion in a vertical direction;
• and
• a filter covering the opening portion,
• wherein the intermediate transfer belt includes a base layer and a surface layer formed on an outer periphery of the base layer, the surface layer being configured to bear the toner image, and
• wherein a maximum particle diameter of particles capable of passing through the filter is smaller than a thickness of the surface layer.

An image forming apparatus comprising:

• an image forming portion including a photosensitive member and configured to form a toner image on a recording material by using the photosensitive member;
• a fixing portion configured to form a nip portion to nip the recording material, and configured to fix the toner image to the recording material by heating the toner image while conveying the recording material with the nip portion;
• a housing configured to accommodate the image forming portion and the fixing portion and having an opening portion through which an outside of the housing and an inside of the housing communicate with each other, the opening portion being positioned above the nip portion in a vertical direction;
• and
• a filter covering the opening portion,
• wherein the photosensitive member includes a conductive base body and a surface layer portion formed on an outer periphery of the base body, and
• wherein the filter is formed from a plastic foam of an open cell type, and
• wherein α/(β/γ)<δ is satisfied in a case where α (μm) represents an average value of cell diameters of the plastic foam in a plane orthogonal to a thickness direction of the filter, β (μm) represents a thickness of the filter, γ (μm) represents an average value of cell diameters of the plastic foam in the thickness direction of the filter, and δ (μm) represents a distance from an outer peripheral surface of the base body to a surface of the photosensitive member.