Image formation apparatus

Abstract

To constitute an electric contact by using an elastic member such as a torsion coil spring regardless of an attachment method of a power source substrate.SOLUTION: An image formation apparatus according to the present invention comprises: image formation means which forms an image on a recording material; a printed circuit board on which voltage generation means for generating the voltage applied to a process member is mounted; a conductive member which is provided on the printed circuit board and is applied with the voltage generated by the voltage generation means; and an elastic member which has an arm part that is biased toward the conductive member and connects the conductive member to the process member. The image formation apparatus also comprises a holding unit which can hold the arm part at a position where the arm part of the elastic member does not contact the conductive member.SELECTED DRAWING: Figure 18

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus equipped with a circuit board. [Background technology]

[0002] In an electrophotographic image forming apparatus, an electrostatic latent image is formed on a charged photoreceptor in a charging section, the electrostatic latent image is developed into a toner image in a developing section, and the developed toner image is transferred to a recording material in a transfer section to form an image. Here, a high voltage of several hundred volts to several kilovolts is applied to the charging section, developing section, and transfer section. For this reason, the image forming apparatus is equipped with a circuit board having a high-voltage power supply circuit that generates the high voltage.

[0003] Patent document 1 describes a configuration in which electrical contact is formed using a jumper wire provided on the circuit board and a torsion coil spring provided on the main body side in order to supply high voltage generated in a high-voltage power supply circuit to each process component. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6104189 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the configuration described in Patent Document 1 limits the method for attaching a circuit board to an image forming apparatus. Specifically, the circuit board must be attached to the image forming apparatus while pressing a jumper wire attached to the circuit board against the arm of a torsion coil spring that is biased in a predetermined direction. For example, the circuit board must be attached to the image forming apparatus by inserting it from the side opposite to the biasing direction of the arm of the torsion coil spring. Because of this limitation on the attachment method, there are cases where the configuration described in Patent Document 1 cannot be used depending on the configuration of the image forming apparatus or circuit board.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an electrical contact using an elastic member such as a torsion coil spring, regardless of the method of mounting the circuit board. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the image forming apparatus of the present invention comprises an image forming means for forming an image on a recording material, a printed circuit board on which a voltage generating means for generating a voltage to be applied to the image forming means is mounted, a conductive member provided on the printed circuit board and to which the voltage generated by the voltage generating means is applied, and an elastic member having an arm portion that is biased toward the conductive member and connects the conductive member to the image forming means, and is characterized in that it also comprises a holding portion that is capable of holding the arm portion of the elastic member in a position where it does not come into contact with the conductive member. [Effects of the Invention]

[0008] As described above, according to the present invention, an electrical contact can be formed using an elastic member such as a torsion coil spring, regardless of the method of mounting the circuit board. [Brief explanation of the drawings]

[0009] [Figure 1] Perspective view of an image forming apparatus [Figure 2] Cross-sectional view of an image forming apparatus [Figure 3] FIG. 1 is a perspective view illustrating the position of a circuit board. [Figure 4] A front perspective view illustrating the position of the circuit board [Figure 5] A perspective view of a circuit board and its peripheral components [Figure 6] Side view of the circuit board and its peripheral components [Figure 7] Top view of the circuit board and its peripheral components [Figure 8] FIG. 10 is a perspective view illustrating a holding configuration for an optical box and a drive motor. [Figure 9]Diagram for explaining electronic components on a circuit board [Figure 10] Block diagram to explain the function of the circuit board [Figure 11] FIG. 1 is a perspective view showing the configuration of an electrical contact; [Figure 12] Cross-sectional view showing the configuration of an electrical contact [Figure 13] Top view to explain the wiring route of the harness [Figure 14] A side view showing the first stage of the process of attaching the circuit board. [Figure 15] A side view showing the second stage of the process of attaching the circuit board. [Figure 16] A side view showing the third stage of the process of attaching the circuit board. [Figure 17] A diagram showing the location of cutouts for electrical contacts on a circuit board. [Figure 18] FIG. 1 is a perspective view showing the configuration of a holding portion of an arm portion of a torsion coil spring according to a first embodiment; [Figure 19] FIG. 10 is a perspective view showing the configuration of a holding portion of an arm portion of a torsion coil spring in Example 2. [Figure 20] FIG. 10 is a perspective view showing the configuration of a holding portion of an arm portion of a torsion coil spring in Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes in detail exemplary embodiments of the present invention with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the embodiments may be changed as appropriate depending on the configuration of the device to which the invention is applied and various conditions. In other words, the scope of the present invention is not limited to the following embodiments.

[0011] Example 1 [Overall configuration of image forming device] The overall configuration of the image forming apparatus 1 in this embodiment will be described. The image forming apparatus 1 in this embodiment is a monochrome laser beam printer that uses an electrophotographic process, and forms an image with a developer (toner) on a recording material P in accordance with image information transmitted from an external device such as a personal computer. Examples of the recording material P include recording paper, label paper, overhead projector sheets, and cloth.

[0012] In the following description, the height direction of the image forming apparatus 1 (the direction opposite to the vertical direction) when the image forming apparatus 1 is installed on a horizontal surface is referred to as the Z direction. The direction that intersects with the Z direction and is parallel to the axial direction (main scanning direction) of the photosensitive drum 11 (described later) is referred to as the X direction. The direction that intersects with the X and Z directions is referred to as the Y direction. The X, Y, and Z directions preferably intersect perpendicularly with each other. For convenience, the positive side in the X direction is referred to as the right side and the negative side is referred to as the left side; the positive side in the Y direction is referred to as the front side or front side and the negative side is referred to as the rear side or back side; and the positive side in the Z direction is referred to as the upper side and the negative side is referred to as the lower side.

[0013] FIG. 1 shows a perspective view of image forming apparatus 1, and FIG. 2 shows a cross-sectional view of image forming apparatus 1 cut along a plane perpendicular to the X direction (the rotational axis direction of photosensitive drum 11). In FIG. 1, image forming apparatus 1 has a feed cassette 4 that stores recording materials P, and an output tray 14 on which discharged recording materials P are stacked. When feed cassette 4 is inserted into feed opening 81, the recording materials P stored in feed cassette 4 become ready to be fed into image forming apparatus 1. In addition, feed cassette 4 can be pulled out from feed opening 81 in the Y direction, allowing the user to replenish recording materials P. The recording materials P that have been fed from feed cassette 4 and on which images have been formed are discharged from output opening 15 in the discharge direction (positive direction of the Y axis) shown in FIG. 1, and are stacked on output tray 14.

[0014] A front cover 70 is provided on a portion of the end face (part of the front face) of the image forming apparatus 1 on the downstream side in the discharge direction, and covers a circuit board 100, which will be described later. An exterior cover 71 is provided on a portion of the front face other than the portion where the front cover 70 is provided, as well as on the side and top faces of the image forming apparatus 1. The front cover 70, the exterior cover 71, and the discharge tray 14 described above together form a housing 75 of the image forming apparatus 1. Here, the housing 75 is a member that covers the entire image forming apparatus 1, and houses process components such as an optical box 50, which will be described later, inside. The above-mentioned feed opening 81 and discharge opening 15 are openings formed in parts of the housing 75, and the recording material P is inserted into the image forming apparatus 1 through the feed opening 81 and is discharged to the outside of the image forming apparatus 1 through the discharge opening 15.

[0015] The flow of an image forming operation on a recording material P will be described using the cross-sectional view of FIG. 2. When image information is sent to the image forming apparatus 1, a photosensitive drum 11 (image carrier), which is a rotating body, is rotated in the direction of arrow R at a predetermined peripheral speed (process speed) based on a print start signal. An optical box 50 irradiates the photosensitive drum 11 with laser light based on the input image information. The optical box 50 is a box-shaped unit that contains components such as a laser oscillator that outputs the laser light, a polygon mirror and lens for irradiating the photosensitive drum 11 with the laser light, and a scanner motor for rotating the polygon mirror. The photosensitive drum 11 is pre-charged by a charging roller 17, and an electrostatic latent image is formed on the photosensitive drum 11 by irradiating it with laser light. Thereafter, the electrostatic latent image is developed with toner by a developing roller 12, forming a toner image on the photosensitive drum 11.

[0016] In parallel with the image formation process described above, recording materials P are fed from a feed cassette 4. A pickup roller 3, a feed roller 5a, and a pair of conveying rollers 5c are provided on the conveyance path of the image forming apparatus 1. The pickup roller 3 (feeding member) comes into contact with the uppermost recording material P stored in the feed cassette 4, and the roller itself rotates to feed the recording material P in the feed direction (the negative Y-axis direction). The feed roller 5a and the separation pad 5b that presses against it form a separation nip. If multiple sheets of recording materials P are fed into the separation nip due to the friction between the recording materials P, the feed roller 5a and the separation pad 5b separate the multiple sheets of recording materials P and feed only the uppermost one downstream.

[0017] The recording material P fed from the feeding cassette 4 is conveyed by a pair of conveying rollers 5c toward a transfer roller 7. A transfer bias is applied to the transfer roller 7, so that the toner image formed on the photosensitive drum 11 is transferred onto the recording material P. The recording material P onto which the toner image has been transferred by the transfer roller 7 is heated and pressurized by a fixing device 9, so that the toner image is fixed onto the recording material P. The fixing device 9 is composed of a heating roller 9a incorporating a heater (not shown), and a pressure roller 9b that is urged toward the heating roller 9a. Then, the recording material P onto which the toner image has been fixed is discharged onto a discharge tray 14 by a pair of discharge rollers 10.

[0018] When an image is formed on both sides of the recording material P, the pair of discharge rollers 10 switches back the recording material P with the image formed on the first side, thereby guiding the recording material P to the double-sided conveying path 16. The recording material P guided to the double-sided conveying path 16 is conveyed again toward the transfer roller 7 by the pair of double-sided conveying rollers 5d. After an image is formed on the second side of the recording material P by the transfer roller 7, the recording material P is discharged outside the apparatus by the pair of discharge rollers 10. After the toner image is transferred to the recording material P, any toner remaining on the photosensitive drum 11 is cleaned by the cleaning unit 13.

[0019] As shown in Fig. 2, the image forming apparatus 1 has a circuit board 100. The circuit board 100 is composed of a printed circuit board 101 made of an insulating material and electronic component groups 111 and 121 soldered to the printed circuit board 101. The printed circuit board 101 is provided with conductive wiring, so that the electronic component groups 111 and 121 are electrically connected. The circuit board 100 is equipped with a converter circuit (not shown) that rectifies a voltage supplied from outside the image forming apparatus 1 and converts the voltage to obtain a predetermined voltage value required for the image formation process.

[0020] 2, the circuit board 100 is oriented such that the surface of the printed circuit board 101 on which the electronic component groups 111 and 121 are mounted intersects with the ejection direction. Furthermore, the printed circuit board 101 is provided between the front cover 70 and the optical box 50 in the ejection direction. The electronic component groups 111 and 121 are provided on the surface of the printed circuit board 101 facing the optical box 50.

[0021] [Circuit board placement] The arrangement of the circuit board 100 in this embodiment will be described in detail using Figures 3 to 8. Figure 3 is a perspective view of the image forming apparatus 1 for explaining the arrangement of the circuit board 100, and unlike Figure 1, the front cover 70 and the exterior cover 71 are omitted. As shown in Figure 3, the circuit board 100 is installed on the front side, and the optical box 50 and the drive motor 60 are provided further back (on the negative side in the Y direction) of the circuit board 100. Note that the optical box 50 and the drive motor 60 are shown in Figure 3 by dotted lines because they are not actually visible.

[0022] 3, the image forming apparatus 1 has a right side plate frame 72 (first side plate frame), a left side plate frame 73 (second side plate frame), and a base frame 74. The right side plate frame 72 supports the right end (first end) of the photosensitive drum 11 in the X direction, and the left side plate frame 73 supports the left end (second end) of the photosensitive drum 11 in the X direction. The base frame 74 is provided on the bottom surface and supports the right side plate frame 72 and the left side plate frame 73 from below.

[0023] The circuit board 100 is supported by these frame members and is mounted on the image forming apparatus 1 with its plate surface approximately parallel to the XZ plane. The right and left side plates 72 and 73 have bent portions 72a and 73a formed at their Y-direction ends for reinforcement. The bent portion 72a is bent toward the positive side of the X direction so as to be approximately parallel to the XZ plane, while the bent portion 73a is bent toward the negative side of the X direction so as to be approximately parallel to the XZ plane. In other words, the bent portions 72a and 73a are bent so as to fit along the surface of the printed circuit board 101. By bending the side plates 72 and 73a toward the outside of the image forming apparatus 1 (away from the photosensitive drum 11 in the X direction), electronic components can be mounted over a larger area of ​​the printed circuit board 101.

[0024] FIG. 4 is a front perspective view of the image forming apparatus 1 for explaining the arrangement of the circuit board 100. As shown in FIG. 4, the distance L1 between the inner surfaces of the right-side plate frame 72 and the left-side plate frame 73 in the X direction is shorter than the length L2 of the circuit board 100 in the X direction. The printed circuit board 101 is disposed on the positive side (front side) of the bent portions 72a and 73a in the Y direction, and the printed circuit board 101 is in contact with each of the bent portions 72a and 73a. When viewed from the front side, the circuit board 100 and the bent portions 72a and 73a overlap. In FIG. 4, the bent portions 72a and 73a, the optical box 50, and part of the drive motor 60 are not actually visible, and are therefore shown with dotted lines.

[0025] [Positional relationship between electronic components and optical box] Next, the positional relationship between the electronic component group 111 and the optical box 50 will be described in detail with reference to FIGS.

[0026] 5 is a perspective view of the circuit board 100 as viewed from the rear of the main body. The electronic component group 111, which is larger in size in the Y direction than the other components, is concentrated below the printed circuit board 101 in order to make effective use of space, and is mounted so as to fit within the lower part of the optical box 50. More specifically, the electronic component group 111 is provided below the center of the printed circuit board 101 in the vertical direction. A power input unit 115 is provided at an end of the printed circuit board 101. The power input unit 115 is connected to an inlet (not shown) and receives power from a commercial power source.

[0027] 6 is an enlarged side view of the circuit board 100 as viewed from the left side of the main body. The optical box 50 is positioned in an optimal position for irradiating the photosensitive drum 11 with the laser light indicated by the chain line. Furthermore, at the location where the optical box 50 and the printed circuit board 101 are closest in the Y direction, no members such as the electronic component group 111 that protrude significantly from the board surface are disposed. In other words, the optical box 50 and the electronic component group 111 are disposed with a shift in the Z direction so as not to interfere with each other.

[0028] 7 is an enlarged top view of circuit board 100 as viewed from above the main body. As can be seen from this view, optical box 50 and electronic component group 111 are positioned so that they partially overlap each other. As mentioned above, because optical box 50 is located above electronic component group 111, electronic component group 111 cannot actually be seen from this direction. In order to clearly show the positional relationship between the two components, optical box 50 is shown by a dotted line in FIG. 7, and electronic component group 111 is shown in perspective.

[0029] In this way, by arranging the electronic component group 111 in the above-mentioned position, the distance between the circuit board 100 and the optical box 50 in the Y direction (front-rear direction) can be shortened, and the image forming apparatus 1 can be made smaller.

[0030] [Positional relationship between electronic components and drive motor] 5 to 7, the positional relationship between the electronic component group 111 and the drive motor 60 will be described in detail. The drive motor 60 plays a role in rotating the members for feeding and conveying the recording material P (the pickup roller 3, the feed roller 5a, the conveying roller pair 5c, etc.) and the photosensitive drum 11.

[0031] As shown in Fig. 5, the drive motor 60 protrudes on the negative side in the X direction, and the printed circuit board 101 is disposed on the front side of the main body relative to the drive motor 60. It can be seen that the electronic component group 111 is mounted away from the drive motor 60 so as not to interfere with it. As shown in Fig. 6, when viewed from the left side of the main body, the drive motor 60 and the electronic component group 111 are disposed in positions where they partially overlap each other. Then, as shown in Fig. 7, when viewed from the top of the main body, the drive motor 60 and the electronic component group 111 are disposed offset in the X direction so as not to interfere with each other.

[0032] In this way, by arranging the electronic component group 111 in the above-mentioned position, the distance between the circuit board 100 and the drive motor 60 in the Y direction (front-rear direction) can be shortened, and the image forming apparatus 1 can be made smaller.

[0033] [Installation configuration to the main unit] Next, the mounting structure of the optical box 50 and the drive motor 60 to the main body will be described in detail using Figure 8. Figure 8 adds a right side plate frame 72 and a scanner holding member 40 to the perspective view of Figure 5. Note that the left side plate frame 73 and base frame 74 are omitted.

[0034] The optical box 50 is held by a scanner holding member 40. The scanner holding member 40 is fixed to a right side plate frame 72 and a left side plate frame 73 (not shown in FIG. 8 ), and is configured to bridge the two frames. Meanwhile, the drive motor 60 is attached to the right side plate frame 72, and a gear connected to the drive motor 60 is provided on the positive side (right side) of the right side plate frame 72 in the X direction. The driving force of the drive motor 60 is transmitted to the feed roller 5a and the photosensitive drum 11 via this gear.

[0035] [Circuit board configuration] Next, the configuration of the circuit board 100 will be described with reference to Fig. 9. Fig. 9 is a rear view of the circuit board 100 as seen from the rear side of the main body. Fig. 9 also illustrates not only the circuit board 100 but also the optical box 50 and the drive motor 60.

[0036] The circuit board 100 is composed of a power supply input unit 115 that takes in AC voltage from a commercial power supply, which is an external power supply, a low-voltage power supply unit 110 that converts AC voltage to DC voltage, and a high-voltage power supply unit 120 that supplies high voltages required for image formation to each process component. In the circuit board 100 of this embodiment, the low-voltage power supply unit 110 and the high-voltage power supply unit 120 are mounted on the same board.

[0037] The low-voltage power supply unit 110 includes a group of electronic components 111 that are large in size in the Y direction, such as a low-voltage power supply transformer 112, a heat sink 113, and an electrolytic capacitor 114. The high-voltage power supply unit 120 includes a group of electronic components 121 that are large in size in the Y direction, such as a charging transformer 122, a developing transformer 123, and a transfer transformer 124. As described above, in order to make better use of the space inside the image forming apparatus 1, the groups of electronic components 111 and 121 that are large in size in the Y direction are all mounted on the inner surface of the image forming apparatus 1 (the negative side in the Y direction) so as to avoid the positions of the optical box 50 and the drive motor 60.

[0038] [Circuit board function] Next, the functions of the low-voltage power supply unit 110 and the high-voltage power supply unit 120 will be described with reference to Figures 9 and 10. Figure 10 is a block diagram for explaining the function of the circuit board 100.

[0039] First, low-voltage power supply unit 110 receives power from a commercial power source via power supply input unit 115 mounted on an end of circuit board 100, and converts the AC voltage into a stable DC voltage using a rectifying and smoothing circuit including electrolytic capacitor 114. Low-voltage power supply unit 110 then converts the DC voltage into a high-frequency AC voltage using switching elements such as transistors, and inputs the high-frequency AC voltage into low-voltage power supply transformer 112. Low-voltage power supply transformer 112 converts the high-frequency AC voltage (the input voltage) into an AC voltage with a desired voltage value. Low-voltage power supply unit 110 again converts the AC voltage into a DC voltage and outputs the resulting DC voltage to high-voltage power supply unit 120, optical box 50, etc. Furthermore, because power loss in each circuit component manifests itself as heat, low-voltage power supply unit 110 is provided with a heat sink 113 made of aluminum or iron for heat dissipation.

[0040] The converter circuit of the above-mentioned low-voltage power supply unit 110 outputs a DC voltage of 24 V, 3.3 V, or 5 V. The 24 V DC voltage is supplied to the high-voltage power supply unit 120, and the 3.3 V or 5 V DC voltage is supplied to the optical box 50, drive motor 60, engine control unit 130, video controller 140, etc. The DC voltage output from the low-voltage power supply unit 110 is supplied to the high-voltage power supply unit 120, optical box 50, drive motor 60, engine control unit 130, video controller 140, etc. via power distribution components such as patterns and harnesses on the printed circuit board 101.

[0041] The high-voltage power supply unit 120 converts the voltage (for example, 24 V) supplied from the low-voltage power supply unit 110 into a high voltage required for the image formation process, such as charging, developing, and transferring. The charging transformer 122 converts the voltage supplied from the low-voltage power supply unit 110 into a charging voltage, and the converted voltage is then supplied to the charging roller 17. The developing transformer 123 converts the voltage supplied from the low-voltage power supply unit 110 into a developing voltage, and the converted voltage is then supplied to the developing roller 12. The transfer transformer 124 converts the voltage supplied from the low-voltage power supply unit 110 into a transfer voltage, and the converted voltage is then supplied to the transfer roller 7.

[0042] The optical box 50, the drive motor 60, the engine control unit 130, and the video controller 140 are operated by a voltage (e.g., 3.3 V or 5 V) supplied from the low-voltage power supply unit 110. The engine control unit 130 is responsible for overall control of various process components. The engine control unit 130 includes a CPU (not shown), a RAM (not shown) used for calculations and temporary storage of data necessary for controlling the image forming apparatus 1, and a ROM (not shown) for storing programs and various data for controlling the image forming apparatus 1. The engine control unit 130 may be provided on a board separate from the circuit board 100, or may be provided on the same board as the circuit board 100. The video controller 140 is responsible for communicating with an external device such as a personal computer to receive print data and for notifying the engine control unit 130 of the results of analyzing the print data.

[0043] [Electrical contact configuration] Next, the configuration of the electrical contacts for supplying the voltage output from the high-voltage power supply unit 120 to each process component will be described with reference to Figures 11 and 12. Figure 11 shows a perspective view of a charging contact unit 159 provided on the edge of the printed circuit board 101, and Figure 12 shows a cross-sectional view of the charging contact unit 159 provided on the edge of the printed circuit board 101. Note that although the configuration of the charging electrical contacts will be described here, the electrical contacts for development and transfer have similar configurations.

[0044] As described above, the high-voltage power supply unit 120 converts the voltage supplied from the low-voltage power supply unit 110 into a high voltage for charging using a charging converter circuit (not shown) including the charging transformer 122. In other words, the high-voltage power supply unit 120 functions as a voltage generating means for generating a high voltage for charging. This high voltage is then supplied to a jumper wire 150 shown in FIG. 11. The jumper wire 150 (conductive member) is provided so as to straddle a notch 153 that penetrates the component surface and the solder surface of the printed circuit board 101. The notch 153 is designed to allow an arm portion 152 of a charging contact spring 151 (elastic member) to fit into it, and when the arm portion 152 fits in, the jumper wire 150 and the arm portion 152 come into contact.

[0045] 12, charging contact spring 151 is in the form of a torsion coil spring, and arm portion 152 is set to apply force in the direction of jumper wire 150. As a result, arm portion 152 is configured to push jumper wire 150 in the direction of arrow 155 shown in FIGS. 11 and 12, thereby stabilizing the electrical contact.

[0046] 12, the charging contact spring 151 has two arms. One arm 152 is configured to be able to come into contact with the jumper wire 150 as described above, and the other arm 154 is connected to the charging roller 17 (not shown in FIG. 12). Therefore, when the arm 152 comes into contact with the jumper wire 150 and functions as an electrical contact, the high voltage generated by the charging converter circuit can be supplied to the charging roller 17 via the jumper wire 150 and the charging contact spring 151.

[0047] [Installing the circuit board] Next, a method for attaching the circuit board 100 to the image forming apparatus 1 will be described with reference to Fig. 13. Fig. 13 is a top view of the circuit board 100 as seen from above the image forming apparatus 1.

[0048] FIG. 13 shows a board-side connector 161 mounted on the printed circuit board 101, a motor-side connector 162 of the drive motor 60, and a harness 160 connecting the board-side connector 161 and the motor-side connector 162. By mounting the board-side connector 161 to which the harness 160 is connected on the same surface as the electronic component groups 111 and 112 and arranging the wiring path of the harness 160 and the process components (such as the optical box 50) in an offset manner, the space within the housing can be effectively utilized. Furthermore, by shortening the distance between the board-side connector 161 and the motor-side connector 162, the required length of the harness 160 can be shortened, thereby reducing the space required for wiring. Therefore, in order to reduce the size of the image forming apparatus 1, it is desirable that the board-side connector 161 be close to the motor-side connector 162.

[0049] However, when the board-side connector 161 is located close to the motor-side connector 162, as described with reference to Figures 3 to 6, it is difficult for an operator to connect the board-side connector 161 and the motor-side connector 162 when the circuit board 100 is attached to the image forming apparatus 1. The board-side connector 161 is hidden behind the printed circuit board 101 when viewed from the front, and behind the drive motor 60 when viewed from the right. Furthermore, because the optical box 50 and the tall electronic component group 121 are provided above the drive motor 60, the space available for an operator to access the board-side connector 161 from above is limited.

[0050] In this way, in order to miniaturize the image forming apparatus 1, when the wiring path of the harness 160 is designed to utilize the space inside the housing, it is difficult to perform the wiring work of the harness 160 in a state where the circuit board 100 is attached to the image forming apparatus 1. Therefore, in this embodiment, the wiring work of the harness 160 is performed before the circuit board 100 is attached.

[0051] 14 to 16 are side views showing the procedure for attaching the circuit board 100 to the image forming apparatus 1 while connecting the harness 160. As mentioned above, wiring cannot be performed while the circuit board 100 is attached to the image forming apparatus 1, so wiring work is first performed on the lower part of the image forming apparatus 1 with the circuit board 100 in a laid-down state as shown in Fig. 14. In the laid-down state, a working space is created on the top side of the image forming apparatus 1 (positive side in the Z direction), so wiring work can be performed between the harness 160 on the lower part and the board-side connector 161.

[0052] 13, the electronic component group 111 is provided to the left (negative side in the X direction) of the board-side connector 161, and therefore part of the board-side connector 161 cannot be seen in the side views of Figures 14 to 16. However, for the sake of explanation, Figures 14 to 16 show the board-side connector 161 in a manner that allows the electronic component group 111 to be seen through.

[0053] Next, as shown in Fig. 15, circuit board 100 is raised partway, wiring work is performed on the middle section, and harness 163 is connected to board-side connector 164. Finally, as shown in Fig. 16, wiring work is performed on the upper section with circuit board 100 attached to image forming apparatus 1, and harness 166 is connected to board-side connector 167. By attaching circuit board 100 to image forming apparatus 1 in an upright position, wiring work with board-side connector 161 becomes possible while shortening the length of harness 160.

[0054] Here, the description has focused on the connector 161 and harness 160 connected to the drive motor 60 as an example, but the procedure for wiring work is not limited to this. For example, in a configuration in which the board-side connector 164 connected to the connector 165 of the optical box 50 and the board-side connector 167 connected to the connector 168 of a process member (not shown) are provided on the lower stage, the wiring work for these may be performed before the wiring work for the drive motor 60.

[0055] [Position of the notch on the circuit board] Next, the positions of the notches provided for electrical contacts in the circuit board 100 will be described with reference to Figure 17. Figure 17 is a rear view of the circuit board 100 as seen from the rear side of the main body.

[0056] 17, a notch 153 constituting part of the charging contact portion 159 described with reference to FIGS. 11 and 12 is provided on the edge of the circuit board 100 on the positive side in the X direction. A jumper wire 150 is provided so as to straddle this notch 153. In addition to this, a development jumper wire 200 and a notch 201, and a transfer jumper wire 202 and a notch 203 are provided on the edge of the circuit board 100 on the positive side in the X direction. Note that hereinafter, when the term "notch" is simply used, this includes the notches 153, 183, and 193 constituting the respective electrical contacts for charging, development, and transfer.

[0057] In such a configuration, conventionally, the circuit board 100 has been attached by inserting it into the image forming apparatus 1 from the negative side in the X direction. However, when attaching the circuit board 100 using the procedure described with reference to Figures 14 to 16, there is a risk that the circuit board 100 and the arm portion of the torsion coil spring will interfere with each other when the circuit board 100 is raised. Therefore, measures such as making the size of the notch larger than conventional ones or shaping the arm portion of the torsion coil spring to match the trajectory are required.

[0058] Furthermore, even if the size of the notch provided in the circuit board 100 is increased to prevent interference between the circuit board 100 and the torsion coil spring, the jumper wire and the arm portion may come into contact at an angle, which may result in an unstable connection of the electrical contacts. In addition, there are concerns that increasing the size of the notch may reduce the rigidity of the circuit board 100 and reduce the mounting space for the circuit board 100. Furthermore, in the configuration of this embodiment, since wiring work is performed in parallel when the circuit board 100 is raised, it is not desirable to perform wiring work in an unstable state where the circuit board 100 is receiving a repulsive force from the torsion coil spring.

[0059] For the above reasons, in this embodiment, the image forming apparatus 1 is provided with a holding portion for holding the arm portion of the torsion coil spring.

[0060] [Configuration of the holding part of the torsion coil spring arm] Fig. 18 is a perspective view showing the configuration of a holding portion for holding the arm portion of the torsion coil spring in this embodiment. Note that while the configuration of the holding portion for the charging electrical contacts described using Figs. 11 and 12 will be described here, the holding portions for the development and transfer electrical contacts also have a similar configuration.

[0061] 18 shows a holding portion 170 that holds an arm portion 152 that is part of a charging contact spring 151 (not shown in FIG. 18) that has a torsion coil spring shape. The holding portion 170 temporarily holds the arm portion 152 at a position where the arm portion 152 does not come into contact with the jumper wire 150 (hereinafter referred to as the retracted position) so that the arm portion 152 does not get into the track when the circuit board 100 is attached.

[0062] Holding portion 170 is provided on the main body of image forming apparatus 1 and is fixed to, for example, right side panel frame 72 (shown in FIG. 8, etc.). Holding portion 170 has receiving portion 171 that receives force acting on arm portion 152 in the direction of arrow 175, and further has L-shaped notch 172 formed in holding portion 170. As described above, arm portion 152 is biased in the direction toward jumper wire 150 by the action of the torsion coil spring.

[0063] With arm portion 152 held by holding portion 170, the worker attaches circuit board 100 to image forming apparatus 1 in the procedure shown in Figures 14 to 16, and then removes arm portion 152 from holding portion 170. This allows arm portion 152 and jumper wire 150 to come into stable contact with each other, as shown in Figure 11.

[0064] Furthermore, notch 153 provided in printed circuit board 101 has a shape that widens as it approaches the edge of printed circuit board 101. This widened portion is guide portion 156, which is configured to guide arm portion 152, which has been removed from holding portion 170, to jumper wire 150.

[0065] As described above, according to this embodiment, the electrical contact can be configured using an elastic member such as a torsion coil spring, regardless of the method of mounting the circuit board.

[0066] Furthermore, by attaching the circuit board according to the procedure shown in Figures 14 to 16, the space inside the housing of the image forming apparatus can be effectively utilized. Furthermore, by configuring the electrical contacts using torsion coil springs, the area required for the contact portions of the circuit board can be reduced. As a result, the image forming apparatus can be further miniaturized.

[0067] Example 2 As described in the first embodiment, the arm portion 152 is held in the retracted position by the holding portion 170 until the circuit board 100 is attached to the image forming apparatus 1 and the arm portion 152 is connected to the jumper wire 150. However, the arm portion 152 may come off the holding portion 170 due to vibrations during the assembly process or an assembly worker accidentally touching the arm portion 152. If the arm portion 152 comes off the holding portion 170, the force of the torsion coil spring will cause the arm portion 152 to move inside the image forming apparatus 1. In this state, the circuit board 100 cannot be attached to the image forming apparatus 1, and therefore the arm portion 152 must be returned to the holding portion 170, which increases the effort required for the attachment process.

[0068] 19 is a perspective view showing the configuration of a holding portion for holding the arm portion of the torsion coil spring in this embodiment. Note that a description of the same configuration as in Example 1 will be omitted, and only the differences from Example 1 will be described.

[0069] 19 shows a holding portion 180 that holds an arm portion 152 that is part of a torsion coil spring-shaped charging contact spring 151 (not shown in FIG. 19). In addition to the receiving portion 181 and notch 182 described in the first embodiment, the holding portion 180 has a protrusion 182 that extends from a part of the receiving portion 181 in the direction opposite to the jumper wire 150. The protrusion 182 prevents the arm portion 152 held by the holding portion 180 from coming off due to vibration or the like. This prevents the above-mentioned increase in the effort required for the installation work.

[0070] As described above, this embodiment has the following effect in addition to the effect of embodiment 1. That is, by providing protrusion 182, it is possible to prevent arm portion 152 from easily coming off holding portion 180 due to vibration or unintended contact when mounting circuit board 100 to image forming apparatus 1, thereby preventing an increase in the amount of mounting work.

[0071] The shape of the protrusion 182 in this embodiment is an example and is not limited to this. Any other shape may be used as long as it makes it difficult for the arm portion 152 to come off the holding portion 180.

[0072] Example 3 As explained in the first embodiment, before mounting the circuit board 100 on the image forming apparatus 1, it is necessary to move the arm portion 152 of the torsion coil spring to the retracted position in advance. On the other hand, when removing the mounted circuit board 100, it is necessary to move the arm portion 152 from the position where the arm portion 152 is in contact with the jumper wire 150 (contact position) to the retracted position. In either case, the worker needs to move the arm portion 152, but in order to make the image forming apparatus 1 compact, it is also necessary to make the holding portion 170 as small as possible. If the holding portion 170 is small, the size of the notch 172 also becomes small, making it difficult for the worker to insert the arm portion 152 into the holding portion 170.

[0073] 20 is a perspective view showing the configuration of a holding portion for holding the arm portion of the torsion coil spring in this embodiment. Note that a description of the same configuration as in Example 1 will be omitted, and only differences from Example 1 will be described.

[0074] 20 shows a holding portion 190 that holds an arm portion 152 that is part of a torsion coil spring-shaped charging contact spring 151 (not shown in FIG. 20). In addition to the receiving portion 191 and notch 192 described in the first embodiment, the holding portion 190 is provided with a guide portion 193 near the entrance of the notch 192. The notch 192 in this embodiment has a shape that widens as it approaches the jumper wire 150, and this widened portion is the guide portion 193. The shape of the guide portion 193 makes it easier for the operator to move the arm portion 152 from the contact position to the retracted position (it is easier for the arm portion 152 to be held by the holding portion 190), which is expected to improve workability.

[0075] As described above, this embodiment has the following advantages in addition to the advantages of the first embodiment: By providing the guide portion 193, the workability when removing the circuit board 100 from the image forming apparatus 1 can be improved.

[0076] The shape of the guide portion 193 in this embodiment is an example and is not limited to this. Any other shape may be used as long as it can guide the arm portion 152 into the notch 192 of the holding portion 190.

[0077] (Variation) In the above-described first to third embodiments, all of the electrical contacts for charging, developing, and transferring are described as having the same configuration, but it is of course possible for only one of these to have the configuration of the first to third embodiments, with the others having different configurations. Also, as described with reference to FIG. 17 , in the above-described first to third embodiments, the jumper wires and notches for the electrical contacts for charging, developing, and transferring are provided on the edge of the circuit board 100 on the positive side in the X direction. However, this is not limiting. For example, only charging may be provided on the edge on the positive side in the X direction, and development and transfer may be provided on the edge on the negative side in the X direction.

[0078] Furthermore, in the above-described first to third embodiments, the charging roller 17, the developing roller 12, and the transfer roller 7 are used as examples of image forming means, but the present invention is not limited to these. For example, the configuration of the present invention may be applied to electrical contacts for applying voltage to members such as the drive motor 60 and the optical box 50. In other words, the configuration of the present invention is not limited to the electrical contacts of the high-voltage power supply unit 120, but may also be applied to the electrical contacts of the low-voltage power supply unit 110.

[0079] In addition, in the above-described first to third embodiments, a torsion coil spring is used as the elastic member, but the present invention is not limited to this and may be, for example, a conductive member with an elastic structure such as a leaf spring. Furthermore, the conductive member is not limited to a linear member such as a jumper wire, but may be, for example, a flat metal member. Furthermore, the shape of the notch is not limited to a square shape and may be, for example, a circle, an ellipse, or a polygon.

[0080] In addition, in the above-described first to third embodiments, the circuit board 100 is attached to the image forming apparatus 1 by standing up, but the present invention is not limited to this. For example, the circuit board 100 may be attached by inserting it into the image forming apparatus 1, or by rotating it relative to the image forming apparatus 1.

[0081] Furthermore, in the above-described first to third embodiments, the low-voltage power supply unit 110 and the high-voltage power supply unit 120 are provided on the same board (circuit board 100), but the present invention is not limited to this. The two power supply units may be provided on separate boards. The boards for the low-voltage power supply unit 110 and the high-voltage power supply unit 120 may both be provided on the front side of the image forming apparatus 1 shown in FIG. 3. Alternatively, only the board for the low-voltage power supply unit 110 may be provided on the front side, and the board for the high-voltage power supply unit 120 may be provided in a different position. Alternatively, only the board for the high-voltage power supply unit 120 may be provided on the front side, and the board for the low-voltage power supply unit 110 may be provided in a different position. [Explanation of symbols]

[0082] 1. Image forming device 17 Charging roller 101 Printed Circuit Board 120 High voltage power supply unit 150 Jumper Wire 151 Charged contact spring 152 Arm 170 Holding part

Claims

1. an image forming means for forming an image on a recording material; a printed circuit board on which a voltage generating unit for generating a voltage to be applied to the image forming unit is mounted; a conductive member provided on the printed circuit board and to which the voltage generated by the voltage generating means is applied; an elastic member having an arm portion biased toward the conductive member and contacting the conductive member, the elastic member being electrically connected to the image forming unit; a holding portion located downstream of the conductive member in a first direction opposite to a direction in which the arm portion is biased toward the conductive member; having the elastic member is configured to be movable to a retracted position where the elastic member is located downstream of the conductive member in the first direction and where the elastic member is held by the holding portion.

1. An image forming apparatus comprising:

2. 2. The image forming apparatus according to claim 1, wherein the holding portion has an L-shaped notch for allowing the elastic member to move to the retracted position.

3. 2. The image forming apparatus according to claim 1, wherein the holding portion includes a receiving portion that receives a force from the arm portion, and a protrusion extending in the first direction from a part of the receiving portion, the protrusion preventing the arm portion from coming off the receiving portion.

4. 2. The image forming apparatus according to claim 1, wherein the holding portion has a notch formed therein for allowing the elastic member to move to the retracted position, the notch having a shape that widens as it approaches the direction in which the arm portion is urged toward the conductive member.

5. 5. The image forming apparatus according to claim 1, wherein a notch is provided on an edge of the printed circuit board, and the conductive member is a jumper wire provided so as to straddle the notch.

6. 6. The image forming apparatus according to claim 5, wherein the notch has a shape that widens toward an edge of the printed circuit board.

7. 7. The image forming apparatus according to claim 1, wherein the elastic member is a torsion coil spring having a second arm portion in addition to the arm portion, and the second arm portion is connected to the image forming means.

8. 8. The image forming apparatus according to claim 1, wherein the image forming means is any one of a charging means for charging an image carrier, a developing means for forming an image on the image carrier, and a transfer means for transferring the image formed on the image carrier to a recording material.

Images