Patent Description:
Power devices that converts commercial alternating current power into direct current power by rectifying and smoothing the commercial alternating current power have been used in image forming apparatuses such as laser beam printers. Such power devices obtain desired output power by inputting the rectified and smoothed direct current power to a transformer and switching the input power, and include a rectification circuit that rectifies input alternating current power and a smoothing circuit that smooths the rectified current.

The smoothing circuit needs a high-capacitance capacitor, so that an electrolytic capacitor is sometimes used. Application of an excessive voltage to the electrolytic capacitor causes gas to be generated inside the capacitor. In order to prevent an increase in pressure in the capacitor due to the gas, the electrolytic capacitor includes a cutout referred to as an explosion-proof valve (also referred to as "pressure valve"). In a case where the explosion-proof valve operates, the gas containing an electrolyte spurts outwardly from the inside of the capacitor. The spurted electrolyte is a conductive liquid, so that adhesion of the electrolyte to a nearby circuit may affect the circuit. Specifically, in a case where the electrolyte adheres to a primary circuit, a short circuit may occur, and this may cause a high current to flow.

Considering such an issue, <CIT> discusses a deflector plate situated to face an explosion-proof valve of an electrolytic capacitor so that an electrolyte spurted in a case where the explosion-proof valve is opened is guided by the deflector plate to areas of circuits that are not likely to be affected by adhesion of the electrolyte. Specifically, the spurted electrolyte is guided to a secondary circuit by the deflector plate without adhering to a primary circuit.

According to <CIT>, a circuit board is built in an image forming apparatus such that a mounting surface of the circuit board is substantially in a vertical direction. Further, the electrolytic capacitor mounted on the circuit board extends in a substantially horizontal direction. In such foregoing configuration, the electrolyte spurted in the substantially horizontal direction in a case where the explosion-proof valve is opened is guided to the secondary circuit by the deflector plate situated to face the explosion-proof valve, while some of the electrolyte flows to an area under the electrolytic capacitor in the vertical direction.

With the configuration discussed in <CIT>, the above-described issue of short circuits does not occur because the primary circuit is not provided under the electrolytic capacitor in the vertical direction. However, in order to realize circuit layouts with more freedom, an effect of the electrolyte spurted in a case where the explosion-proof valve is opened is desirably reduced even in a configuration in which an electric element is provided under the electrolytic capacitor in the vertical direction.

The present invention is directed to preventing adhesion of an electrolyte spurted from an electrolytic capacitor to an electric element provided under an electrolytic capacitor in a vertical direction.

According to an aspect of the present invention, there is provided an image forming apparatus as specified in claims <NUM> to <NUM>, <NUM> and <NUM>.

According to another aspect of the present invention, there is provided an image forming apparatus as specified in claims <NUM> to <NUM>.

A power device <NUM> according to a first exemplary embodiment of the present invention that is applied to an image forming apparatus will now be described. <FIG> is an overall view illustrating a laser beam printer <NUM> (hereinafter, referred to as "printer <NUM>") as an example of an image forming apparatus. The printer <NUM> includes a photosensitive drum <NUM>, a charging device <NUM>, and a development device <NUM>. The photosensitive drum <NUM> is an image bearing member on which an electrostatic latent image is to be formed. The charging device <NUM> uniformly charges the photosensitive drum <NUM>. The development device <NUM> develops an electrostatic latent image formed on the photosensitive drum <NUM> using toner. A toner image developed on the photosensitive drum <NUM> is transferred at a transfer portion <NUM> to a sheet as a recording material fed from a cassette <NUM>. The transferred toner image on the sheet is then fixed by a fixing device <NUM> heated by a heater <NUM>. The sheet with the fixed toner image thereon is discharged to a sheet discharge tray <NUM>. The printer <NUM> includes the power device <NUM> that supplies power to a driving unit, such as a motor, and to a control unit <NUM>. The control unit <NUM> controls, for example, the above-described image forming operations, conveying sheets, and a temperature of the heater <NUM>.

<FIG> is a circuit block diagram illustrating the power device <NUM> according to the first exemplary embodiment. A flyback-type switching power supply will be described here as an example. An alternating-current voltage Vac is supplied from a commercial power supply <NUM> to the power device <NUM>. The alternating-current voltage Vac supplied to the power device <NUM> is supplied to a diode bridge <NUM> via a fuse <NUM> and a filter circuit <NUM>. If the alternating-current voltage Vac is rectified by the diode bridge <NUM>, a pulsating current waveform with one side being positive is obtained. The voltage with the pulsating current waveform is smoothed to a substantially direct current by an action of a primary electrolytic capacitor <NUM>. A voltage applied to both ends of the primary electrolytic capacitor <NUM> will be referred to as "voltage Vdc". A potential of a positive terminal of the primary electrolytic capacitor <NUM> will be referred to as "potential DCH", and a potential of a negative terminal of the primary electrolytic capacitor <NUM> will be referred to as "potential DCL".

The smoothed voltage Vdc is input to a primary winding Np of a transformer <NUM>, and is fed back via a field-effect transistor (FET) <NUM> to the commercial power supply <NUM> through the negative terminal of the primary electrolytic capacitor <NUM> and the diode bridge <NUM>. The ON/OFF timings of the FET <NUM> are controlled by a switching control unit <NUM>. Before the switching is started, the switching control unit <NUM> acquires operation power from a terminal ST, whereas after the switching is started, the switching control unit <NUM> acquires operation power from a voltage between terminals VB and VS, which is generated from an auxiliary winding Nb of the transformer <NUM>. The terminal VS of the switching control unit <NUM> is connected to the potential DCL.

A rectification unit <NUM> is connected to a secondary winding Ns of the transformer <NUM>. Power converted to a voltage by the transformer <NUM> is fed to the rectification unit <NUM>, and the rectification unit <NUM> rectifies and smooths the fed voltage to obtain a direct current voltage Vout. The direct-current voltage Vout is output to a load <NUM> outside the power device <NUM>. The load <NUM> includes, for example, a central processing unit (CPU) (not illustrated) of the control unit <NUM> illustrated in <FIG> and the driving unit such as a motor. The direct-current voltage Vout is connected to a voltage feedback unit <NUM>, and the voltage feedback unit <NUM> outputs information indicating whether the direct-current voltage Vout is a predetermined voltage. Specifically, the voltage feedback unit <NUM> outputs a voltage as an electric signal between terminals FB and VS of the switching control unit <NUM>. The voltage feedback unit <NUM> includes primary and secondary circuits insulated from each other, and an element, such as a photocoupler, transmits electric signals from the secondary circuit to the primary circuit. The switching control unit <NUM> determines the ON/OFF timings of the FET <NUM> based on a voltage value between the terminals FB and VS and controls the output voltage Vout to be a predetermined voltage value.

A layout of the power device <NUM> in the printer <NUM> will now be described with reference to <FIG>. In <FIG>, a height direction (direction opposite to the vertical direction) of the printer <NUM> placed on a horizontal surface is defined as a Z-direction. A direction that intersects the Z-direction and is parallel to a rotation axis direction (main scan direction) of the photosensitive drum <NUM> (illustrated in <FIG>) is defined as an X-direction. A direction that intersects the X-direction and Z-direction is defined as a Y-direction. The X-, Y-, and Z-directions desirably intersect perpendicularly to each other. The XYZ directions also apply to the subsequent drawings.

As illustrated in <FIG>, the printer <NUM> includes a power supply casing <NUM> therein. The power supply casing <NUM> is a box-shaped member specified by a dotted line and includes the power device <NUM> therein. The power device <NUM> includes a circuit board <NUM> specified by a dash-dot-dash line and the primary electrolytic capacitor <NUM> mounted on the circuit board <NUM>. As described above, the power device <NUM> further includes various other electric elements, but illustrations thereof are omitted in <FIG>.

The circuit board <NUM> is situated substantially perpendicularly to a horizontal plane, and a surface of the circuit board <NUM> extends substantially parallel to an XZ plane. The circuit board <NUM> is also fixed to an inner wall of the power supply casing <NUM> with screws <NUM>. The primary electrolytic capacitor <NUM> is mounted on the circuit board <NUM> such that the electrolytic capacitor <NUM> protrudes toward a negative side in the Y-direction. In contrast, the commercial power supply <NUM> (illustrated in <FIG>) is connected to an inlet <NUM> via a power supply cable (not illustrated), and the inlet <NUM> is connected to the power device <NUM> via cables <NUM>.

<FIG> is a perspective view illustrating a configuration of the power device <NUM> according to the present exemplary embodiment. Only major components are illustrated in <FIG>. The circuit board <NUM> includes the primary electrolytic capacitor <NUM>, the diode bridge <NUM>, a heatsink <NUM> (plate-shaped member), and jumper wires <NUM> and <NUM> (electric elements) in this order from the top in the Z-direction. A surface of the circuit board <NUM> on the negative side in the Y-direction on which the foregoing components are mounted is referred to as a mounting surface <NUM>. The diode bridge <NUM> among the components on the circuit board <NUM> is likely to generate heat, and therefore the diode bridge <NUM> is mounted directly on the heatsink <NUM> to be in contact with the heatsink <NUM>. The jumper wires <NUM> and <NUM> are electric elements for pattern wiring of the circuit board <NUM>. The jumper wire <NUM> has a potential equal to the potential DCL, and the jumper wire <NUM> has a potential equal to the potential DCH.

As described above, the primary electrolytic capacitor <NUM> protrudes toward the negative side in the Y-direction, and an explosion-proof valve <NUM> (also referred to as "pressure valve") is provided to a distal end of the primary electrolytic capacitor <NUM>. In a case where a voltage that is higher than or equal to a predetermined value is applied to the primary electrolytic capacitor <NUM> due to an abnormality, the explosion-proof valve <NUM> opens and releases gas containing an electrolyte outwardly, whereby an increase in pressure in the primary electrolytic capacitor <NUM> is prevented. Since the electrolyte is a conductive liquid, adhesion of the electrolyte to a path between the jumper wires <NUM> and <NUM>, which are two electric elements having a different potential from each other, may cause a short circuit at the path, and this may cause an excessive current to flow. Thus, adhesion of the electrolyte to electronic components such as the jumper wires <NUM> and <NUM> needs to be prevented.

In order to prevent adhesion of the electrolyte to the jumper wires <NUM> and <NUM>, the heatsink <NUM> between the primary electrolytic capacitor <NUM> and the jumper wires <NUM> and <NUM> in the vertical direction has a devised shape in the configuration according to the present exemplary embodiment. As illustrated in <FIG>, the heatsink <NUM> includes a cutout <NUM>. The cutout <NUM> is formed in a side <NUM> near the circuit board <NUM> in the direction (the negative side in the Y-direction) in which the primary electrolytic capacitor <NUM> protrudes. Further, the heatsink <NUM> includes one bent portion and surfaces <NUM> and <NUM>. The diode bridge <NUM> is mounted on the surface <NUM> (predetermined surface), and the surface <NUM> intersects the surface <NUM> substantially perpendicularly to the surface <NUM>. The cutout <NUM> is formed at a bent portion <NUM> where the two surfaces <NUM> and <NUM> intersect.

The four corners of the surface <NUM> of the heatsink <NUM> will be referred to as points A, B, C, and D. The point A is positioned at an end portion of the surface <NUM> on the negative side in the Y-direction and a positive side in the X-direction. The point B is positioned at an end portion of the surface <NUM> on the negative side in the Y-direction and a negative side in the X-direction. The point C is positioned at an end portion of the cutout <NUM> on the negative side in the Y-direction. The point D is positioned at an end portion of the surface <NUM> on a positive side in the Y-direction and the positive side in the X-direction.

The heatsink <NUM> is basically mounted substantially perpendicularly to the mounting surface <NUM> of the circuit board <NUM>. In reality, however, the heatsink <NUM> may be mounted slightly obliquely to the circuit board <NUM> within an accuracy variation range. Thus, in the configuration illustrated in <FIG> in which the jumper wires <NUM> and <NUM> are situated under the point C in the vertical direction, adhesion of the electrolyte to the jumper wires <NUM> and <NUM> needs to be prevented regardless of in which direction the heatsink <NUM> is tilted. <FIG> below illustrate states where the heatsink <NUM> tilted in different directions is mounted.

<FIG> is a view illustrating the power device <NUM> and the power supply casing <NUM> as viewed along the mounting surface <NUM> of the circuit board <NUM>. Specifically, <FIG> is a view illustrating the power device <NUM> and the power supply casing <NUM> as viewed from the positive side to the negative side in the X-direction. <FIG> illustrates a state where the explosion-proof valve <NUM> opens and an electrolyte <NUM> spurted from the primary electrolytic capacitor <NUM> is scattered in different directions and adheres to an inner wall <NUM>, which faces the primary electrolytic capacitor <NUM>, of the power supply casing <NUM> and an upper surface of the heatsink <NUM>. The heatsink <NUM> is tilted with respect to the mounting surface <NUM>, and in <FIG>, a position (the point C) of an end portion of the heatsink <NUM> that is near the circuit board <NUM> is lower in the vertical direction than a position (the point B) of another end portion of the heatsink <NUM> that is on an opposite side from the circuit board <NUM>.

In <FIG>, the heatsink <NUM> is tilted, so that the electrolyte <NUM> scattered onto the heatsink <NUM> flows from the point B to the point C. Since the heatsink <NUM> includes the cutout <NUM> (illustrated in <FIG>), the electrolyte <NUM> falls downward in the vertical direction from the point C. As illustrated in <FIG>, a position Y2 of the point C in the Y-direction is farther from the circuit board <NUM> than a position Y1 of the jumper wires <NUM> and <NUM> exposed from the mounting surface <NUM> in the Y-direction is from the circuit board <NUM>. Specifically, a position of at least part of an area where the cutout <NUM> is formed is farther in the Y-direction from the mounting surface <NUM> of the circuit board <NUM> than the position of the jumper wires <NUM> and <NUM> is from the circuit board <NUM>. Thus, the electrolyte <NUM> having fallen from the point C falls to a bottom surface of the power supply casing <NUM> without adhering to the jumper wires <NUM> and <NUM>.

Specifically, with the cutout <NUM>, the electrolyte <NUM> that previously falls after being guided to a position near the circuit board <NUM> falls from a position far from the circuit board <NUM>. This prevents adhesion of the electrolyte <NUM> to the jumper wires <NUM> and <NUM> situated under the primary electrolytic capacitor <NUM> in the vertical direction.

<FIG> illustrates a state where the heatsink <NUM> is tilted in a direction opposite to the tilt direction illustrated in <FIG>. In <FIG>, the position (the point C) of the end portion of the heatsink <NUM> that is near the circuit board <NUM> is higher in the vertical direction than the position (the point B) of the other end portion of the heatsink <NUM> that is on the opposite side from the circuit board <NUM>. In this case, the electrolyte <NUM> scattered onto the heatsink <NUM> flows from the point C to the point B, so that the electrolyte <NUM> falls downward in the vertical direction from the point B in <FIG>. As illustrated in <FIG>, a position Y4 of the point B in the Y-direction is farther from the circuit board <NUM> than the position Y1 of the jumper wires <NUM> and <NUM> exposed from the mounting surface <NUM> in the Y-direction is from the circuit board <NUM>. Thus, the electrolyte <NUM> having fallen from the point B falls to the bottom surface of the power supply casing <NUM> without adhering to the jumper wires <NUM> and <NUM>.

The position Y4 of the point B in the Y-direction is also farther from the circuit board <NUM> than a position Y3 of a distal end portion of the primary electrolytic capacitor <NUM> is from the circuit board <NUM>. In other words, the heatsink <NUM> protrudes beyond the primary electrolytic capacitor <NUM> from the circuit board <NUM>. Thus, the heatsink <NUM> plays a role as a kind of an umbrella for the jumper wires <NUM> and <NUM> and prevents the electrolyte <NUM> spurted from the distal end portion of the primary electrolytic capacitor <NUM> from being reflected by the inner wall <NUM> and adhering to the jumper wires <NUM> and <NUM>. This effect is similarly obtained also in the state illustrated in <FIG>.

<FIG> is a diagram illustrating the power device <NUM> as viewed from a direction perpendicular to the mounting surface <NUM> of the circuit board <NUM>. Specifically, <FIG> is a diagram illustrating the power device <NUM> as viewed from the negative side to the positive side in the Y-direction. Further, as illustrated in <FIG>, the surface <NUM> of the heatsink <NUM> on which the diode bridge <NUM> is mounted extends in a direction intersecting the perpendicular direction, and the surface <NUM> is tilted with respect to the horizontal direction such that the position of the point A is higher in the vertical direction than the position of the point B.

In this case, the electrolyte <NUM> scattered onto the heatsink <NUM> flows to a downstream end in the vertical direction, i.e., from the point A to the point B. Since the surface <NUM> of the heatsink <NUM> is tilted with respect to the horizontal direction, the electrolyte <NUM> is guided to the bent portion <NUM>. The bent portion <NUM> is formed by bending the heatsink <NUM>, whereby the electrolyte <NUM> having flown to the point B is accumulated at the bent portion <NUM>. Thereafter, as illustrated in <FIG> or <FIG>, the electrolyte <NUM> gathered at the bent portion <NUM> flows to the point B or C depending on the direction in which the heatsink <NUM> is tilted. In both states, the electrolyte <NUM> does not adhere to the jumper wires <NUM> and <NUM> as described above with reference to <FIG> and <FIG>.

<FIG> illustrates a state where the heatsink <NUM> is tilted in a direction opposite to the tilt direction illustrated in <FIG>. In <FIG>, the surface <NUM> of the heatsink <NUM> extends in the direction intersecting the perpendicular direction, and the surface <NUM> is tilted such that the position of the point A is lower in the vertical direction than the position of the point B. In this configuration, the electrolyte <NUM> scattered onto the heatsink <NUM> flows from the point B to the point A and falls to an area far from the position of the jumper wires <NUM> and <NUM> in the X-direction.

The above prevents adhesion of the electrolyte <NUM> to the jumper wires <NUM> and <NUM>.

As described above, the configuration in which the jumper wires <NUM> and <NUM> are provided under the point C in the vertical direction includes the cutout <NUM> to prevent adhesion of the electrolyte <NUM> to the electric element regardless of in which direction the heatsink <NUM> is tilted.

While <FIG> illustrate the heatsink <NUM> tilted with respect to the mounting surface <NUM> of the circuit board <NUM>, the heatsink <NUM> can be not tilted with respect to the mounting surface <NUM> and can be substantially perpendicular to the mounting surface <NUM>.

While the jumper wires <NUM> and <NUM> are provided under the point C in the vertical direction in the above-described configuration, a cutout can be formed at a position near the point D in a case where the jumper wires <NUM> and <NUM> are provided under the point D in the vertical direction. This configuration will be described below.

<FIG> is a perspective view illustrating the power device <NUM> with the jumper wires <NUM> and <NUM> provided under the point D in the vertical direction. The heatsink <NUM> includes not only the cutout <NUM> but also a cutout <NUM> near the point D. A point E is positioned at an end portion of the cutout <NUM> on the negative side in the Y-direction. The cutout <NUM> is optional.

<FIG> is a view illustrating the power device <NUM> in <FIG> as viewed from a direction perpendicular to the mounting surface <NUM> of the circuit board <NUM>. <FIG> illustrates a state where the surface <NUM> of the heatsink <NUM> is tilted with respect to the horizontal direction due to an effect of accuracy variations. Since the surface <NUM> is tilted such that the position of the point B is higher in the vertical direction than the position of the point A, the electrolyte <NUM> scattered onto the heatsink <NUM> flows from the point B to the point A.

<FIG> is a view illustrating the power device <NUM> and the power supply casing <NUM> in <FIG> as viewed along the mounting surface <NUM> of the circuit board <NUM>. In the configuration illustrated in <FIG>, since the position of the point E is lower in the vertical direction than the position of the point A, the electrolyte <NUM> flows from the point A to the point E. Consequently, the electrolyte <NUM> falls downward in the vertical direction from the point E. A position Y6 of the point E in the Y-direction is farther from the circuit board <NUM> than a position Y5 of the jumper wires <NUM> and <NUM> exposed from the mounting surface <NUM> in the Y-direction is from the circuit board <NUM>. Thus, the electrolyte <NUM> having fallen from the point E falls to the bottom surface of the power supply casing <NUM> without adhering to the jumper wires <NUM> and <NUM>.

The state where the heatsink <NUM> is tilted and mounted in a direction different from the tilt directions illustrated in <FIG> and <FIG> is similar to those described above with reference to <FIG>, and therefore redundant descriptions thereof are omitted.

As described above, the configuration in which the jumper wires <NUM> and <NUM> are provided under the point D in the vertical direction includes the cutout <NUM> to prevent adhesion of the electrolyte <NUM> to the jumper wires <NUM> and <NUM>.

While the cutouts are formed in the end portions of the heatsink <NUM> in the above-described configurations according to the first exemplary embodiment, aspects of the present invention are not limited to the configurations described above. As illustrated in <FIG>, the heatsink <NUM> can include a hole <NUM> therein. The electrolyte <NUM> scattered onto the heatsink <NUM> falls downward in the vertical direction from the hole <NUM> at a position far from the mounting surface <NUM> of the circuit board <NUM>. This configuration similarly prevents adhesion of the electrolyte <NUM> to the jumper wires <NUM> and <NUM>.

Further, while the above-described configurations according to the first exemplary embodiment include a cutout or a hole at the bent portion <NUM> of the heatsink <NUM>, aspects of the present invention are not limited to the configurations. For example, while the cutout <NUM> is positioned at the bent portion <NUM>, i.e., at the downstream end of the heatsink <NUM> in the vertical direction that is tilted with respect to the horizontal direction in <FIG>, the cutout <NUM> can be formed at a position that is slightly shifted to the positive side in the X-direction from the bent portion <NUM>.

As described above, according to the present exemplary embodiment, the heatsink <NUM> includes a cutout or a hole to prevent the electrolyte <NUM> spurted from the primary electrolytic capacitor <NUM> from adhering to the jumper wires <NUM> and <NUM>.

The above-described configurations according to the first exemplary embodiment prevent adhesion of the electrolyte <NUM> to the jumper wires <NUM> and <NUM> using the heatsink <NUM> mounted on the circuit board <NUM>. However, there may be a case where the power device <NUM> does not include the heatsink <NUM>.

According to a second exemplary embodiment, a dedicated member for preventing adhesion of the electrolyte <NUM> to the jumper wires <NUM> and <NUM> is intentionally tilted with respect to the mounting surface <NUM> to be mounted on the mounting surface <NUM> in the tilted state. A basic apparatus configuration of the second exemplary embodiment is similar to that according to the first exemplary embodiment, and thus redundant descriptions thereof are omitted. A configuration that is different from the first exemplary embodiment will be described here.

<FIG> illustrates a configuration of the power device <NUM> that includes a guide plate <NUM> (plate-shaped member) for guiding the electrolyte <NUM>. <FIG> is a diagram illustrating the power device <NUM> as viewed along the mounting surface <NUM> of the circuit board <NUM>. In <FIG>, the guide plate <NUM> is positioned between the primary electrolytic capacitor <NUM> and the diode bridge <NUM> in the Z-direction, and is installed so as to incline in the -Z direction as the distance from the circuit board <NUM> increases.

The guide plate <NUM> is a member for guiding the electrolyte <NUM> to a position far from the jumper wires <NUM> and <NUM>. The guide plate <NUM> is, for example, a resin member. Further, the guide plate <NUM> is mounted on the circuit board <NUM> in a state of being intentionally tilted with respect to the mounting surface <NUM> rather than being tilted within the accuracy variation range. Specifically, a tilt angle θ of the guide plate <NUM> with respect to an extension line extending perpendicularly to the mounting surface <NUM> of the circuit board <NUM> is desirably <NUM> degrees or greater.

In this configuration, the electrolyte <NUM> having adhered to the guide plate <NUM> flows to the negative side in the Y-direction and falls in the negative Z-direction from a distal end portion <NUM> of the guide plate <NUM> on the negative side in the Y-direction. Thus, the electrolyte <NUM> falls to the bottom surface of the power supply casing <NUM> without adhering to the jumper wires <NUM> and <NUM>.

As described above, according to the present exemplary embodiment, the guide plate <NUM> for guiding the electrolyte <NUM> is provided to prevent adhesion of the electrolyte <NUM> spurted from the primary electrolytic capacitor <NUM> to the jumper wires <NUM> and <NUM> even in a case where a plate-shaped member such as the heatsink <NUM> is not provided.

While the heatsink <NUM> includes a cutout or a hole in the configurations according to the first exemplary embodiment, aspects of the present invention are not limited to the configurations. The guide plate <NUM> according to the second exemplary embodiment can be provided in place of the heatsink <NUM>, and a cutout or a hole can be formed in the guide plate <NUM>.

Further, while the guide plate <NUM> is intentionally tilted and mounted on the mounting surface <NUM> in the configuration according to the second exemplary embodiment, aspects of the present invention are not limited to the configuration. The heatsink <NUM> according to the first exemplary embodiment can be provided in place of the guide plate <NUM>, and the heatsink <NUM> can be intentionally tilted and mounted on the mounting surface <NUM>.

Further, while the diode bridge <NUM> is mounted on the heatsink <NUM> according to the first and second exemplary embodiments, aspects of the present invention are not limited to the configurations. The FET <NUM>, which is a switching element, and a rectification diode (not illustrated) of the rectification unit <NUM> of the secondary circuit are other components that are likely to generate heat, and these components can be in contact with the heatsink <NUM>.

While the jumper wires <NUM> and <NUM> are described as an example of an electric element provided under the primary electrolytic capacitor <NUM> in the vertical direction according to the first and second exemplary embodiments, the two electric elements do not necessarily have to be provided. For example, only the jumper wire <NUM> can be provided. In this case, adhesion of the electrolyte <NUM> to an area near the jumper wire <NUM> may cause a short circuit between the jumper wire <NUM> and the bottom surface of the power supply casing <NUM> or the ground. Further, since the heatsink <NUM> has a predetermined potential, a short circuit may occur between the jumper wire <NUM> and the heatsink <NUM>. Furthermore, the electric element is not limited to the jumper wire <NUM> and can be another electric element provided to the primary circuit of the transformer <NUM>, such as a resistor or a diode.

Claim 1:
An image forming apparatus comprising: image forming means for forming an image on a recording material; and
a power device (<NUM>) for supplying power to the image forming means, the power device including a circuit board (<NUM>) provided to intersect a horizontal plane (X),
wherein the power device includes:
an electrolytic capacitor (<NUM>) including an explosion-proof valve (<NUM>) for opening and spurting an inside electrolyte outwardly in a case where a voltage higher than or equal to a predetermined value is applied, the electrolytic capacitor protruding in a first direction (Y) from a mounting surface (<NUM>) of the circuit board;
an electric element (<NUM>, <NUM>) under the electrolytic capacitor in a vertical direction (Z), the electric element being exposed from the mounting surface; and
a plate-shaped member (<NUM>) provided between the electrolytic capacitor and the electric element in the vertical direction, the plate-shaped member including a first surface (<NUM>) extending in a second direction (X) intersecting the vertical direction as viewed in a direction perpendicular to the mounting surface of the circuit board,
wherein the plate-shaped member includes a cutout or a hole (<NUM>), and a position of at least part of an area where the cutout or the hole is formed is farther in the first direction (Y) from the mounting surface of the circuit board than a position of the electric element.