An optional device is for an electrical machine. The optional device is mountable to the electrical machine without electrical connection to the electrical machine. The optional device includes a duct, an air flow sensor, an air purifier, and a controller. Through the duct, an air flow containing an exhaust gas from the electrical machine is guided. The air flow sensor is configured to detect presence or absence of the exhaust gas from the electrical machine. The air purifier is configured to purify the exhaust gas and discharge the purified exhaust gas into an atmosphere. The controller is configured to control an operation of the air purifier based on an output from the air flow sensor.

A feeding apparatus comprises a locking unit for locking a connected state between an image forming apparatus and the feeding apparatus; an operating unit to which a force is applied in a separating direction in order to separate the feeding apparatus from the image forming apparatus and configured to perform an unlocking operation of unlocking the locking unit by being operated upon application of the force in the separating direction; and a handgrip unit provided at a position different from a position of the operating unit and to which a force is applied in the separating direction in order to separate the feeding apparatus from the image forming apparatus. The handgrip unit extends in a second horizontal direction perpendicular to a first horizontal direction and is arranged at a position at least partially overlapping a position where the operating unit is arranged with respect to the first horizontal direction.

An image forming apparatus includes a housing unit that includes an intermediate plate, a lift-up unit, a first detection unit, a second detection unit, a feeding unit, a control unit, a first acquisition unit that acquires a first driving amount, a storage unit that stores a threshold, a determination unit that determines that a recording material is overloaded on the intermediate plate when the first driving amount is smaller than the threshold, a second acquisition unit that acquires a second driving amount, a correction unit that obtains a differential amount by subtracting a predetermined driving amount from the second driving amount acquired by the second acquisition unit, and corrects, on a basis of the differential amount, the threshold stored in the storage unit or the first driving amount acquired by the first acquisition unit.

An image forming apparatus includes a height determining member that performs the positioning of a holder in a height direction. When the holder is not mounted, the height determining member is assembled to a predetermined frame member to serve as a part of the predetermined frame member.

A sheet conveyor device is to be attachably and detachably mounted to an external apparatus which forms an image on a sheet. The sheet conveyor device includes a judgement section, a speed determining section, and a conveyance controller. The judgement section determines which of a plurality of model groups the external apparatus belongs to based on specification information indicating specifications of the external apparatus. The speed determining section determines a conveyance speed at which the sheet is to be conveyed based on the determined model group. The conveyance controller directs conveyance of the sheet at the determined conveyance speed.

An accessory mating system for mating a print engine to an accessory may include a pin and a pin receiving detent. The pin has a collar having a pin vertical axis datum surface and a shaft extending from the collar. The shaft provides left-right axis datum surfaces and second opposite sides providing fore-aft axis datum surfaces. The pin receiving detent receives the pin. The pin receiving detent may include a detent perimeter providing a detent vertical axis datum surface, first opposite internal sides providing first detent left-right axis datum surfaces facing the pin left-right axis datum surfaces and second opposite internal sides providing detent fore-aft axis datum surfaces.

An attachment unit for attaching a second device to a first device includes a first attachment member and a second attachment member. Each of the first attachment member and the second attachment member has first to Nth engagement sections. N is an integer of at least 2. The first to Nth engagement sections of the first attachment member respectively have the same shape as the first to Nth engagement sections of the second attachment member. The nth engagement section of the first attachment member is engageable with the (Nn+1)th engagement section of the second attachment member. n is an integer of at least 1 and no greater than N. At least one of the first device and the second device is an image forming apparatus or an extension device.

An image forming apparatus includes a height determining member that performs the positioning of a holder in a height direction. When the holder is not mounted, the height determining member is assembled to a predetermined frame member to serve as a part of the predetermined frame member.

An image forming apparatus includes a main body, a post-printing processing device, and a paper exit part. The main body forms an image on paper. The post-printing processing device is located above the main body and performs post-printing processing on paper. The paper exit part is located on a side surface of the post-printing processing device. Paper is ejected to the paper exit part. The post-printing processing device includes a paper inlet port and a conveyance device. The paper inlet port is located in a rear part of a lower surface of the post-printing processing device. The conveyance device conveys paper conveyed via the paper inlet port into the post-printing processing device in a forward direction thereof to a paper loading tray and conveys the paper therefrom leftward to eject the paper to the paper exit part located on the left side of the post-printing processing device.

An image forming apparatus includes, an image forming portion configured to form a toner image on a sheet using printing toner and apply powder adhesive on the sheet, a fixing portion configured to heat the toner image formed on the sheet and the powder adhesive applied on the sheet by the image forming portion and fix the toner image and the powder adhesive to the sheet, and a bonding portion configured to bond the sheet with the powder adhesive by reheating the sheet having been heated by the fixing portion. The bonding portion is arranged above the image forming portion.