A printing device includes: a first storage device; a second storage device; a coupling board having a first connector to which the first storage device is directly coupled from a first direction and a second connector to which the second storage device is directly coupled from a second direction that is different from the first direction, the coupling board being a rigid board; a printing mechanism executing print processing; a control board where a control circuit controlling the printing mechanism is provided; and a coupling mechanism to which the control board and the coupling board are coupled.

A holder holds a heater. A connector includes a connection terminal. The connector is configured to be attached to the holder by sandwiching a part of the holder and a part of the heater. The connection terminal is configured to be connected to a power supply terminal in a state where the connector is attached to the holder. The connector includes a body part and a claw. The body part sandwiches the part of the holder and the part of the heater in a state where the connector is attached to the holder. The claw protrudes in a direction away from the body part. The holder includes an engagement part. The engagement part is configured to engage with the claw from an upstream side in an attaching direction. The attaching direction is a direction in which the connector is attached to the holder.

A power source apparatus including: a transformer including a primary coil, a secondary coil, and an auxiliary coil, and has a primary side and a secondary side which are insulated from each other; a rectifier circuit including a first output terminal and a second output terminal; a smoothing capacitor; a switching element; a first series circuit having a capacitor and a first rectification element connected in series; and a second series circuit having a second rectification element and the auxiliary coil connected in series. The number of turns of the auxiliary coil is smaller than the number of turns of the primary coil. A product a ratio between the number of turns of the auxiliary coil and the number of turns of the secondary coil and an output voltage on the secondary side of the transformer is equal to or lower than a voltage of the smoothing capacitor.

Power to an electrical device is controlled using a phase control that changes a cutoff phase of an alternating current (AC) electrical signal delivered to the electrical device. The power delivered to the electrical device is increased to an operational level using the phase control. A level of the power delivered to the electrical device is maintained at the operational level using an integral half cycle control that selectively removes a plurality of half cycles from the AC electrical signal delivered to the electrical device such that a plurality of remaining half cycles in the AC electrical signal delivered to the electrical device have a frequency outside a range of sub-harmonic frequencies.

An image forming apparatus includes an image bearing member, an optical sensor configured to detect a pattern image formed on the image bearing member, and an attachment member to which the optical sensor is attached. The optical sensor includes a circuit board, a light emitting element and a light receiving element which are provided on a first side of the circuit board, and a connector provided on a second side opposite to the first side of the circuit board. The attachment member has a surface contacting the second side of the circuit board. In an insertion/removal direction of a cable to be connected to the connector, a first thickness, from the surface, of a part of a portion, contacting the second side, of the attachment member is smaller than a second thickness, from the surface, of a portion, not contacting the second side, of the attachment member.

A control circuit of an image forming apparatus outputs a pulse signal. A clock signal generation circuit generates a clock signal, based on the pulse signal. A pulse signal conversion circuit generates a pulse conversion control signal of a voltage value associated with a duty ratio of the pulse signal. An AC voltage generation circuit generates an AC voltage of a frequency based on the clock signal. Either the AC voltage generation circuit or a DC voltage generation circuit generates a voltage whose amplitude or voltage value increases as a voltage value of the received pulse conversion control signal increases, and whose amplitude or voltage value decreases as a voltage value of the pulse conversion control signal decreases.

A power supply apparatus includes a transformer, an electrolytic capacitor provided in primary circuitry of the transformer, a board, and a heat sink having a protruding portion and a cover portion. The electrolytic capacitor includes an explosion-proof valve that opens to cause an electrolytic solution to be jetted from the electrolytic capacitor. The electrolytic capacitor is placed on the board so that a surface of the electrolytic capacitor opposite to a surface on which the explosion-proof valve is provided faces the board. The cover portion has a hole formed in the cover portion and, when the cover portion is viewed in a direction vertical to the surface of the electrolytic capacitor on which the explosion-proof valve is provided, at least the explosion-proof valve and the hole formed in the cover portion do not overlap each other and the cover portion encompasses the explosion-proof valve.

An image forming apparatus includes a housing, a door, an inlet, a primary power source, a secondary power source, a primary interlock switch, and a secondary interlock switch. The housing has an opening. The door is hinge-coupled to the housing by a hinge, and opens and closes the opening. The inlet is provided near the hinge. The secondary power source is provided farther from the inlet than the primary power source. The primary interlock switch is provided on a primary electric circuit between the inlet and the primary power source, and is turned off when the door is opened. The secondary interlock switch is provided on a secondary electric circuit between the primary power source and the secondary power source, and is turned off when the door is opened. The primary interlock switch is disposed closer to the inlet than the secondary interlock switch.

A sheet feeding apparatus includes an upper support portion formed integrally with a side plate and configured to support an electric circuit board; an upper opening portion formed in the side plate near the upper support portion; a lower support portion provided at a separate part mounted to the side plate and configured to support the electric circuit board; and a lower opening portion provided between the side plate and the separate part. All line segments having a length of 50 mm or less, among line segments extending from arbitrary points in a main body portion of a sheet cassette, through arbitrary points in the upper opening portion, to the electric circuit board, form an angle of 45° or more with respect to a vertical line, and the lower opening portion has a dimension of 5 mm or less or a width of 1 mm or less.

A printer system includes a first apparatus including a first voltage source for converting an inputted AC voltage to a first DC voltage and for outputting the converted first DC voltage, and a first controller operable by a voltage based on the first DC voltage outputted from the first voltage source; and a second apparatus including a second voltage source for converting an inputted AC voltage to a second DC voltage and for outputting the converted second DC voltage, and a second controller operable by a voltage based on the first DC voltage outputted from the first voltage source. The second apparatus includes a first switching portion for switching a state thereof between a connection state in which the AC voltage is supplied to the second voltage source and a non-connection state in which supply of the AC voltage is cut off.