Image forming apparatus

Abstract

In a configuration where a unit is electrically connected to the main housing of an image forming apparatus, unwanted radiation caused by the unit acting as an antenna is suppressed. [Solution] The image forming apparatus has a grounded main body housing and comprises a main body for printing, a unit connected to the main body for performing predetermined printing processing, and a grounding part that electrically connects the unit and the main body housing. The grounding part comprises a conductor having a mounting part at one end for attaching to the main body housing and a contact part at the other end for contacting the unit, and a ferrite core that covers the intermediate portion of the conductor between the mounting part and the contact part.

Description

Technical Field

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[0001] <孤 The present invention relates to an image forming apparatus including a main body and a unit connected thereto.

Background Art

[0002] Conventional image forming apparatuses can connect various units to a main body that performs printing. As a unit that can be connected to the main body of an image forming apparatus, for example, there is a paper feeding unit that feeds sheets to the main body (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, an image forming apparatus includes a grounded main body housing. A unit connected to the main body of the image forming apparatus is electrically connected to the main body housing. Thereby, static electricity generated in the unit can flow to the main body housing.

[0005] However, in a configuration where a unit is electrically connected to the main body housing, the unit may become an antenna for unnecessary radiation, and unnecessary radiation may increase. When unnecessary radiation increases, inconveniences such as malfunction may occur.

[0006] The present invention has been made to solve the above problems, and an object thereof is to provide an image forming apparatus capable of suppressing unnecessary radiation due to antenna formation of a unit in a configuration where the unit is electrically connected to the main body housing of the image forming apparatus.

[0007] ​To achieve the above objective, an image forming apparatus according to one aspect of the present invention comprises a main body having a grounded main body housing, a main body for performing printing, a unit connected to the main body for performing predetermined printing processing, and a grounding portion for electrically connecting the unit and the main body housing. The grounding portion comprises a conductor having a mounting portion at one end for being attached to the main body housing and a contact portion at the other end for contacting the unit, and a ferrite core covering the intermediate portion of the conductor between the mounting portion and the contact portion. [Effects of the Invention]

[0008] In the configuration of the present invention, in a configuration in which the unit is electrically connected to the main body housing of the image forming apparatus, unwanted radiation due to the unit acting as an antenna can be suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of an image forming apparatus according to an embodiment. [Figure 2] This is a perspective view of the main body side member and the unit side member according to the embodiment. [Figure 3] This is a perspective view of the main body side member according to the embodiment, seen from below. [Figure 4] This is a perspective view of a leaf spring for a paper feed unit according to an embodiment. [Figure 5] This diagram schematically shows the electrical connection points between the paper feeding unit and the main body housing according to the embodiment. [Figure 6] This is a schematic cross-sectional view showing the structure of a segmented ferrite core according to an embodiment. [Figure 7] Figure 6 is a schematic cross-sectional view showing a pair of divided bodies separated from each other. [Figure 8] This is a schematic cross-sectional view showing the structure of an undivided ferrite core according to an embodiment. [Figure 9] This figure shows the experimental results (experimental results when using a ferrite core) obtained to confirm the effectiveness of the embodiment. [Figure 10]This figure shows the experimental results (experimental results without using a ferrite core) obtained to confirm the effectiveness of the embodiment. [Modes for carrying out the invention]

[0010] The following describes an image forming apparatus 100 according to one embodiment of the present invention, with reference to Figures 1 to 10.

[0011] In the following explanation, the direction perpendicular to the flat floor surface on which the image forming apparatus 100 is installed will be referred to as the vertical direction D. Note that the vertical direction D is the vertical direction. Furthermore, of the horizontal directions perpendicular to the vertical direction D, one direction will be referred to as the left-right direction D1, and the direction perpendicular to that direction will be referred to as the front-back direction D2. The left-right direction D1 corresponds to the "first direction". The front-back direction D2 corresponds to the "second direction".

[0012] As shown in Figure 1, the image forming apparatus 100 of this embodiment comprises a main body 1. The main body 1 has a printing unit. The printing unit prints images on paper and sheets such as cloth. In other words, the main body 1 performs printing. The printing method of the printing unit may be an inkjet method or an electrophotographic method.

[0013] If the printing method of the printing unit is an inkjet method, the printing unit is equipped with at least an ink head. The printing unit prints an image onto a sheet using ink. That is, the printing unit ejects ink toward the sheet and adheres the ink to the sheet.

[0014] If the printing method of the printing unit is electrophotographic, the printing unit comprises a photosensitive drum, a charging device, a developing device, an exposure device, and a transfer roller. The printing unit prints an image onto a sheet using toner. That is, the printing unit forms an electrostatic latent image and transfers the toner image obtained by developing that electrostatic latent image onto the sheet.

[0015] The main body 1 includes a main body housing 10. The main body housing 10 is made of metal and has conductivity. The main body housing 10 is composed of a sheet metal member or the like. The main body housing 10 includes a frame, an exterior cover, and the like. The main body housing 10 supports the components of the printing unit. The main body housing 10 is electrically grounded.

[0016] Also, the image forming apparatus 100 includes a paper feeding unit 2. The paper feeding unit 2 corresponds to a "unit". The paper feeding unit 2 is connected to the main body 1 in the left - right direction D1. When the paper feeding unit 2 is connected to the main body 1, the paper feeding unit 2 is disposed on the right side of the main body 1. For example, the paper feeding unit 2 is an optional device and can be connected to and disconnected from the main body 1. In FIG. 1, for the sake of convenience, a state where the paper feeding unit 2 is separated from the main body 1 is shown.

[0017] The paper feeding unit 2 includes a unit housing 20. The unit housing 20 is made of metal and has conductivity. The unit housing 20 is composed of a sheet metal member or the like. The unit housing 20 includes a frame, an exterior cover, and the like. The unit housing 20 supports the components of the paper feeding unit 2. The unit housing 20 is electrically connected to the grounded main body housing 10. That is, the paper feeding unit 2 is grounded.

[0018] The paper feeding unit 2 performs a predetermined process related to printing. The predetermined process performed by the paper feeding unit 2 is a feeding process of feeding a sheet to the main body 1. When a sheet is fed from the paper feeding unit 2 to the main body 1, printing is performed on the sheet.

[0019] Also, the image forming apparatus 100 includes a finisher 3. The finisher 3 is connected to the main body 1 in the left - right direction D1. When the finisher 3 is connected to the main body 1, the finisher 3 is disposed on the left side of the main body 1. For example, the finisher 3 is an optional device and can be connected to and disconnected from the main body 1. In FIG. 1, for the sake of convenience, a state where the finisher 3 is separated from the main body 1 is shown.

[0020] The finisher 3 comprises a finisher housing 30. The finisher housing 30 is made of metal and is conductive. The finisher housing 30 is composed of sheet metal members and the like. The finisher housing 30 includes a frame and an outer cover. The finisher housing 30 supports the components of the finisher 3. The finisher housing 30 is electrically connected to the grounded main housing 10. That is, the finisher 3 is grounded.

[0021] The finisher 3 performs predetermined processing related to printing. This predetermined processing includes post-processing such as punching and stapling. The finisher 3 performs post-processing on the printed sheets fed from the main unit 1. The post-processing described here is just one example; other post-processing may also be performed.

[0022] <Connecting the paper feed unit> To connect the paper feeding unit 2 to the main body 1, a connecting guide mechanism as shown in Figures 2 and 3 is used. This connecting guide mechanism includes a main body side member 11 and a unit side member 21. The main body 1 is equipped with the main body side member 11. The paper feeding unit 2 is equipped with the unit side member 21. Figure 2 shows the main body side member 11 and the unit side member 21 assembled together. When the paper feeding unit 2 is connected to the main body 1, the state shown in Figure 2 is achieved. Figure 3 shows the lower side of the main body side member 11.

[0023] The main body side member 11 is made of sheet metal and is conductive. The main body side member 11 is fixed to the main body housing 10 with screws. In this way, the main body side member 11 is electrically connected to the main body housing 10.

[0024] The main body side member 11 is positioned on the lower right of the main body housing 10 (see Figure 1). Specifically, the main body side member 11 is positioned on the lower surface of the main body housing 10. The main body side member 11 integrally includes a portion 11a that is positioned on the right side of the main body housing 10. The portion 11a of the main body side member 11 is attached to the lower right frame of the main body housing 10.

[0025] The main body side member 11 has a pair of outer guides G1 that extend in the left-right direction D1 and face each other in the front-rear direction D2. The outer guides G1 correspond to "guides". The main body side member 11, including the pair of outer guides G1, is formed by sheet metal processing of a single metal plate.

[0026] Specifically, the main body side member 11 has a portion that is bent in a roughly U-shape when viewed from the left-right direction D1. The ends of this roughly U-shaped portion in the front-rear direction D2 each become the outer guides G1. In the following description, the portion of the main body side member 11 between the pair of outer guides G1 in the front-rear direction D2 will be referred to as the outer guide base 111. The pair of outer guides G1 each extend downward from one end and the other end of the outer guide base 111 in the front-rear direction D2.

[0027] The main body 1 also includes a roller 12. The roller 12 is rotatably supported by the main body side member 11. The roller 12 is positioned on the lower surface of the outer guide base 111. That is, the roller 12 is positioned between the pair of outer guides G1 in the front-rear direction D2. The roller 12 is rotatable on the lower surface side of the outer guide base 111 about an axis extending in the vertical direction D. The number of rollers 12 is not particularly limited. For example, there are two rollers 12.

[0028] The unit-side member 21 is made of sheet metal and is electrically conductive. The unit-side member 21 is fixed to the unit housing 20 with screws. This electrically connects the unit-side member 21 to the unit housing 20.

[0029] The unit-side member 21 is positioned at the lower left of the unit housing 20 (see Figure 1). The unit-side member 21 protrudes to the left from the left side of the unit housing 20. The unit-side member 21 integrally includes a portion 21a that is positioned on the left side of the unit housing 20. The portion 21a of the unit-side member 21 is attached to the lower left frame of the unit housing 20. When the paper feed unit 2 is connected to the main body 1, the portion 11a of the main body-side member 11 and the portion 21a of the unit-side member 21 face each other in the left-right direction D1. That is, the state is as shown in Figure 2.

[0030] The unit-side member 21 has a pair of internal guides G2 that extend in the left-right direction D1 and face each other in the front-rear direction D2. The unit-side member 21, including the pair of internal guides G2, is formed by sheet metal processing of a single metal plate.

[0031] Specifically, the unit-side member 21 has a portion that is bent in a roughly U-shape when viewed from the left-right direction D1. The ends of this roughly U-shaped portion in the front-rear direction D2 each become the inner guides G2. In the following description, the portion of the unit-side member 21 between the pair of inner guides G2 in the front-rear direction D2 will be referred to as the inner guide base 211. The pair of inner guides G2 each extend upward from one end and the other end of the inner guide base 211 in the front-rear direction D2.

[0032] The main body member 11 and the unit member 21 function as a slide rail when combined with each other. The main body member 11 becomes the outer rail, and the unit member 21 becomes the inner rail. A pair of outer guides G1 sandwich a pair of inner guides G2 in the front-rear direction D2. In other words, a pair of inner guides G2 are positioned between the pair of outer guides G1 in the front-rear direction D2. Rollers 12 are positioned between the pair of inner guides G2 in the front-rear direction D2.

[0033] The unit-side member 21 is slidable in the left-right direction D1 between the front-rear direction D2 of the pair of outer guides G1. When the unit-side member 21 is positioned between the front-rear direction D2 of the pair of outer guides G1, when the unit-side member 21 moves in the left-right direction D1, the displacement of the unit-side member 21 in the front-rear direction D2 is restricted by the main body-side member 11. In other words, the main body-side member 11 guides the movement of the unit-side member 21 in the left-right direction D1.

[0034] When connecting the paper feed unit 2 to the main unit 1, the unit-side member 21 is positioned between the pair of outer guides G1 in the front-to-back direction D2. Specifically, the pair of inner guides G2 are positioned between the pair of outer guides G1 in the front-to-back direction D2. With the unit-side member 21 positioned between the pair of outer guides G1 in the front-to-back direction D2, the paper feed unit 2 is moved towards the main unit 1 in the left-to-right direction D1. At this time, the movement of the paper feed unit 2 in the left-to-right direction D1 is guided. This brings the paper feed unit 2 to a position where it can be connected to the main unit 1. After that, the paper feed unit 2 is fixed to the main unit 1 and the main unit 1 and the paper feed unit 2 are connected with signal lines.

[0035] <Grounding connection of the paper feed unit> As shown in Figures 3 to 5, the image forming apparatus 100 is equipped with a grounding section 4 for the paper feeding unit 2. The grounding section 4 electrically connects the paper feeding unit 2 to the grounded main body housing 10. The paper feeding unit 2 is electrically connected to the main body housing 10 via the grounding section 4 by being connected to the main body 1 (i.e., reaching the connection position with the main body 1). By electrically connecting the paper feeding unit 2 to the main body housing 10, static electricity generated by the paper feeding unit 2 can be discharged into the main body housing 10.

[0036] The grounding section 4 is equipped with a leaf spring 5 used for grounding the paper feed unit 2. The leaf spring 5 corresponds to a "conductor". The leaf spring 5 is electrically conductive. The leaf spring 5 is made from a rectangular metal plate. The leaf spring 5 is formed by bending the metal plate along a line extending in its shorter direction.

[0037] Here, when the paper feeding unit 2 is connected to the main body 1, the outer guide base 111 is positioned opposite the inner guide base 211 with a gap in the vertical direction D (see Figure 5). The outer guide base 111 is above, and the inner guide base 211 is below. That is, the inner guide base 211 (i.e., the unit side member 21) is positioned opposite the lower surface of the outer guide base 111 (i.e., the lower surface of the main body housing 10) in the vertical direction D.

[0038] Therefore, the leaf spring 5 is attached to the lower surface of the main housing 10. In other words, the leaf spring 5 is positioned opposite the unit-side member 21 in the vertical direction D. Specifically, the leaf spring 5 has a mounting portion 51 at one end in its longitudinal direction. The leaf spring 5 has a contact portion 52 at the other end opposite to the one end in its longitudinal direction.

[0039] The mounting portion 51 is attached to the lower surface of the outer guide base 111. The mounting portion 51 is fixed to the lower surface of the outer guide base 111 with screws Sc. As a result, the leaf spring 5 is attached to the lower surface of the main body housing 10. That is, the leaf spring 5 is positioned between the pair of outer guides G1 in the front-rear direction D2.

[0040] The contact portion 52 protrudes downward from the lower surface of the outer guide base 111. When an upward force is applied to the contact portion 52 from below, the leaf spring 5 undergoes elastic deformation, and the contact portion 52 is displaced upward. When the force on the contact portion 52 is removed, the contact portion 52 returns to its original position.

[0041] When the paper feed unit 2 is connected to the main body 1, the contact portion 52 contacts the inner guide base 211 (i.e., the unit-side member 21) from above. As a result, the leaf spring 5 biases the inner guide base 211 downward. The biasing force of the leaf spring 5 maintains contact between the contact portion 52 and the inner guide base 211.

[0042] In this embodiment, by arranging the leaf spring 5 between the front-rear direction D2 of the pair of outer guides G1, the paper feed unit 2 can be electrically connected to the main body housing 10 simply by connecting the paper feed unit 2 to the main body 1. This eliminates the need to perform a separate operation to electrically connect the paper feed unit 2 to the main body housing 10 after connecting the paper feed unit 2 to the main body 1, thus providing convenience.

[0043] <Suppression of unwanted radiation> In a configuration where the paper feed unit 2 is electrically connected to the main unit housing 10 and grounded, the paper feed unit 2 may act as an antenna emitting high-frequency noise, increasing unwanted radiation. In this case, malfunctions and other problems may occur.

[0044] Therefore, the grounding portion 4 is equipped with a ferrite core 6, as shown in Figure 5. The ferrite core 6 removes high-frequency noise. The ferrite core 6 is placed on the leaf spring 5. By being placed on the intermediate portion 50 of the leaf spring 5, the ferrite core 6 covers the outer surface of the intermediate portion 50. The intermediate portion 50 is the portion of the leaf spring 5 between the mounting portion 51 (i.e., one end in the longitudinal direction) and the contact portion 52 (i.e., the other end in the longitudinal direction). Note that the ferrite core 6 is not placed on the mounting portion 51 or the contact portion 52.

[0045] In this embodiment, by placing the ferrite core 6 in the intermediate portion 50 of the leaf spring 5 used for the electrical connection between the paper feeding unit 2 and the main housing 10, the transmission of high-frequency noise to the paper feeding unit 2 via the leaf spring 5 can be suppressed. This suppresses the radiation of high-frequency noise using the paper feeding unit 2 as an antenna. In other words, unwanted radiation due to the paper feeding unit 2 acting as an antenna can be suppressed.

[0046] In this embodiment, the leaf spring 5 has not been modified from its existing shape. Furthermore, the ferrite core 6 can be attached to the leaf spring 5 without the need for additional mounting components. This helps to suppress the cost increase associated with attaching the ferrite core 6 to the leaf spring 5.

[0047] The structure of the ferrite core 6 is not particularly limited. For example, the ferrite core 6 can be a segmented ferrite core 61 (see Figures 6 and 7) or a non-segmented ferrite core 62 (see Figure 8). Either the segmented ferrite core 61 or the non-segmented ferrite core 62 may be used. The above effects can be obtained regardless of whether the segmented ferrite core 61 or the non-segmented ferrite core 62 is used.

[0048] 1. Split ferrite core The segmented ferrite core 61 has the structure shown in Figures 6 and 7. Figure 6 is a schematic diagram corresponding to a cross-section along line AA' in Figure 5.

[0049] The divided ferrite core 61 is divided into two parts 611 and 612. The divided ferrite core 61 is placed in the case 600. By combining the parts 611 and 612 with each other, a cylindrical body having a through hole 610 is formed. The through hole 610 is flattened when viewed from the direction of the cylindrical axis.

[0050] Case 600 is openable and closable. Opening case 600 separates the segments 611 and 612 from each other. Closing case 600 brings the segments 611 and 612 closer together. Closing case 600 brings the segments 611 and 612 together.

[0051] The leaf spring 5 is sandwiched between the divided parts 611 and 612. By opening the case 600 and closing it with the leaf spring 5 sandwiched inside, the leaf spring 5 can be sandwiched between the divided parts 611 and 612. In this state, the intermediate portion 50 is positioned in the through hole 610. That is, the divided parts 611 and 612 sandwich the intermediate portion 50. As a result, the divided ferrite core 61 is positioned only in the intermediate portion 50 of the leaf spring 5.

[0052] When using a segmented ferrite core 61 as the ferrite core 6, the degree of freedom in attaching the ferrite core 6 to the leaf spring 5 increases. The ferrite core 6 can be attached to the leaf spring 5 even after the leaf spring 5 has been formed (after the metal plate that is the material of the leaf spring 5 has been bent). Specifically, after forming the leaf spring 5, it is only necessary to sandwich the intermediate portion 50 with the segmented parts 611 and 612. However, when using a segmented ferrite core 61, the noise reduction effect may be lower than when using a non-segmented ferrite core 62.

[0053] 2. Undivided ferrite core The undivided ferrite core 62 has the structure shown in Figure 8. Figure 8 is a schematic diagram corresponding to a cross-section along line AA' in Figure 5.

[0054] The undivided ferrite core 62 is a flattened cylindrical body. The undivided ferrite core 62 has a through hole 620. The through hole 620 is flattened when viewed from the direction of the cylindrical axis.

[0055] The leaf spring 5 is inserted into the through hole 620. The intermediate portion 50 is positioned in the through hole 620. The mounting portion 51 and the contact portion 52 protrude from the through hole 620. As a result, the undivided ferrite core 62 is positioned only in the intermediate portion 50 of the leaf spring 5.

[0056] When using a non-divided ferrite core 62 as the ferrite core 6, it is necessary to insert a metal plate into the through hole 620 and then bend the metal plate to form a leaf spring 5. After forming the leaf spring 5, it is difficult to position the ferrite core 6 in the intermediate portion 50. On the other hand, when using a non-divided ferrite core 62 as the ferrite core 6, the noise reduction effect is higher than when using a divided ferrite core 61.

[0057] The following describes the experiment conducted to confirm the noise reduction effect.

[0058] In the verification experiment, unwanted radiation was measured for both cases: with and without a ferrite core 6 placed on the leaf spring 5. A non-split ferrite core 62 was used as the ferrite core 6.

[0059] Figure 9 shows the measurement results when using the ferrite core 6. Figure 10 shows the measurement results when not using the ferrite core 6. Note that when the paper feed unit 2 is grounded to the main unit housing 10, unwanted broadband radiation in the vertical direction occurs, but its frequency band is 230 MHz or less. Therefore, the measurement results are given as 30 MHz to 230 MHz.

[0060] When the ferrite core 6 is not placed on the leaf spring 5, the unwanted radiation level in the 30MHz-40MHz range is high. In contrast, when the ferrite core 6 is placed on the leaf spring 5, unwanted radiation in the 30MHz-40MHz range is suppressed and is lower than the limit line (shown by the dashed line), confirming that the standard is met. Figures 9 and 10 show the peak values. Therefore, although it exceeds the limit line in some places, the standard is met because the QP value (Quasi-Peak) is officially applied.

[0061] <Grounding connection of the finisher> As shown in Figure 1, the image forming apparatus 100 is equipped with a leaf spring 7 for the finisher 3. The leaf spring 7 is formed by sheet metal processing of a conductive metal plate. The leaf spring 7 generates a biasing force in the left-right direction D1.

[0062] The image forming apparatus 100 includes a bracket 70. The bracket 70 is formed by sheet metal processing of a conductive metal plate. The bracket 70 is attached to the finisher housing 30.

[0063] The leaf spring 7 for the finisher 3 is mounted on the bracket 70 and positioned to the lower right of the finisher 3. When the finisher 3 is connected to the main body 1, the leaf spring 7 makes contact with the main body housing 10 from the left, and the leaf spring 7 is electrically connected to the main body housing 10. As a result, the finisher 3 is electrically connected to the grounded main body housing 10.

[0064] Furthermore, the finisher 3 is less susceptible to noise than the paper feed unit 2. Therefore, it is not necessary to place a ferrite core on the leaf spring 7 for the finisher 3. However, a ferrite core may be placed on the leaf spring 7. In this case, the leaf spring 7 and the ferrite core placed on it constitute the "grounding section".

[0065] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the description of the embodiments above, and furthermore, all modifications within the meaning and scope equivalent to the claims are included. [Explanation of Symbols]

[0066] 1 Main unit 2. Paper feed unit (unit) 4 Grounding part 5. Leaf spring (conductive material) 6 ferrite core 10 Main Unit 21 Unit side member 50 middle part 51 Mounting part 52 Contact area 61-part ferrite core (ferrite core) 62 Undivided ferrite core (ferrite core) 611, 612 split field 620 Through hole G1 External Guide (Guide)

Claims

1. The main unit has a grounded housing and performs printing, A unit connected to the main body and performing predetermined printing processes, The unit and the main housing are provided with a grounding section that electrically connects them. The aforementioned grounding portion is A conductor having a mounting portion at one end for attachment to the main housing and a contact portion at the other end for contacting the unit, An image forming apparatus comprising a ferrite core that covers the intermediate portion of the conductor between the mounting portion and the contact portion.

2. The ferrite core is a cylindrical body having a through hole, The image forming apparatus according to claim 1, wherein the conductor is inserted into the through hole.

3. The ferrite core is divided into two parts, The image forming apparatus according to claim 1, wherein the conductor is sandwiched between the two divided bodies.

4. The unit has a unit-side member that is positioned opposite the lower surface of the main housing in the vertical direction, The image forming apparatus according to claim 1, wherein the conductor is a leaf spring, is attached to the lower surface of the main body housing, and contacts the unit side member to bias the unit side member downward.

5. The main housing has a pair of guides that extend in a first direction perpendicular to the vertical direction and that face each other in a second direction perpendicular to the first direction horizontally. The unit-side member is slidable in the first direction between the second directions of the pair of guides, With the unit-side member positioned between the second directions of the pair of guides, the unit is moved toward the main body in the first direction, thereby reaching a position where it can be connected to the main body. The image forming apparatus according to claim 4, wherein the conductor is arranged between the second directions of the pair of guides.

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