JP2008129137A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an image forming apparatus which prevents poor contact between a first switch member and a second switch member, and also prevents accuracy deterioration in terms of application of a transfer bias on a transfer roller. <P>SOLUTION: When a jam access cover 20 is closed with respect to the image forming apparatus main body 12, each projection 46 of a contact part 42 of the first switch member 30 comes in contact with the switch main body part 56 of the second switch member 54. In this case, a prescribed elastic force is applied by respective elastic parts 40 and 44 to the contact part 42, then, prescribed pressurizing force is applied from the contact part 42 to the switch main body part 56. Simultaneously, a reaction force is applied from the switch main body part 56 to the contact part 42, then, the contact part 42 is flexibly deformed. In this case, the prescribed elastic force is applied from each elastic support part 50 to each projection 46, then, the reaction force is applied from the switch main body part 56 to each projection 46, then, each projection 46 is flexibly deformed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus having a first switch member that is electrically connected to a transfer roller, and a second switch member that contacts the first switch member and applies a transfer device to the transfer roller.

  A conventional image forming apparatus is provided with a cover member such as a jam access cover that is opened to clear a paper jam. The cover member is attached with a transfer roller disposed opposite to the photosensitive drum via a bearing case. A transfer bias is applied to the transfer roller from the voltage applying unit, and the toner attached to the outer peripheral surface of the photosensitive drum can be attracted to the sheet side.

Here, as a voltage application unit, a first switch member made of metal having elasticity is attached to the bearing case of the transfer roller, and the first switch member is closed on the image forming apparatus main body side when the cover member is closed. A second switch member that contacts is attached, and a predetermined transfer bias can be applied to the transfer roller by contacting the second switch member.
JP-A-11-202663 JP-A-63-244524

  Meanwhile, the portion of the first switch member that contacts the second switch member is formed in a planar shape or a comb shape. When the portion of the first switch member that contacts the second switch member is planar, the planes contact each other at the contact point between the first switch member and the second switch member. There is a problem of poor contact. Moreover, when the site | part which contacts the 2nd switch member of a 1st switch member is comb shape, the intensity | strength of the site | part which contacts the 2nd switch member of a 1st switch member becomes low, and an unexpected pressure is applied. If it receives, it will bend and there is a problem of poor contact.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that can prevent poor contact between a first switch member and a second switch member and prevent a transfer bias from being applied to a transfer roller from being lowered in accuracy. .

  According to the first aspect of the present invention, a bias applied member, a first switch member electrically connected to the bias applied member and having elasticity and conductivity, a power supply means, and a contact with the first switch member An image forming apparatus including a second switch member capable of applying an arbitrary bias to the biased member, wherein the first switch member and the second switch member are in contact with each other. A plurality of convex portions are formed.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the first switch member includes a base portion that can be attached to another part, a contact portion that contacts the second switch member, A first elastic part extending from an end of the base part to connect the base part and the contact part and applying an elastic force to the contact part; and a first elastic part extending from the contact part And a second elastic part that applies an elastic force to the contact part, and the convex part is formed in the contact part.

  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the convex portion causes a contact plane portion that contacts the second switch member and an elastic force to act on the contact plane portion. And a pair of elastic support portions.

  According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the bias applied member is a transfer roller disposed opposite to the photosensitive drum, and the first A transfer bias is applied to the transfer roller when the switch member and the second switch member come into contact with each other.

  According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the second switch member is provided on the image forming apparatus main body side, and the bias applied member and the The first switch member is provided on a cover member attached to the image forming apparatus main body so as to be openable and closable. When the cover member is closed with respect to the image forming apparatus main body, the first switch member and the second switch member are provided. The transfer bias is applied to the transfer roller by contacting the switch member.

  According to the first aspect of the present invention, when the first switch member and the second switch member come into contact with each other, an arbitrary bias is applied from the second switch member connected to the power supply means to the bias applied member via the first switch member. Can be applied.

  Here, since a plurality of convex portions are formed at the contact portion where the first switch member and the second switch member are in contact with each other, the number of contacts between the first switch member and the second switch member can be increased. . For this reason, regardless of the contact angle between the first switch member and the second switch member, the contact accuracy (degree of freedom of contact) between the first switch member and the second switch member can be increased. Further, since only a plurality of convex portions are formed at the contact portion where the first switch member and the second switch member are in contact with each other, the first switch member and the second switch member are compared with a so-called comb shape. It can prevent that the intensity | strength of the contact site | part which contacts and falls. As a result, poor contact between the first switch member and the second switch member can be prevented. In addition, since the convex part should just be formed in the contact site | part which a 1st switch member and a 2nd switch member contact, the structure currently formed in the site | part on the 1st switch member side, the 2nd switch member side Any of the structures formed at the site may be used.

  According to the invention described in claim 2, the contact portion of the first switch member comes into contact with the second switch member. At this time, an elastic force is applied to the contact portion by the first elastic portion and the second elastic portion. Since it acts, the contact part of a 1st switch member contacts with a predetermined pressure with respect to a 2nd switch member. Thereby, the contact state between the contact portion of the first switch member and the second switch member can be stably maintained. In addition, since the contact portion of the first switch member is elastically supported by the first elastic portion and the second elastic portion, the contact portion of the first switch member is not affected by the posture and the inclination angle of the first switch member, and Contact accuracy (contact degree of freedom) between the contact portion and the second switch member can be increased.

  According to invention of Claim 3, a convex part is comprised by the contact plane part which contacts a 2nd switch member, and a pair of elastic support part which makes an elastic force act on a contact plane part. Yes. Thereby, the elastic force which acts by the 1st elastic part and the 2nd elastic part, and the elastic force which acts by a pair of elastic support part acts on the contact plane part of a convex part. As a result, the strength of the contact portion of the first switch member can be increased by applying a double elastic force to the contact flat surface portion of the convex portion, and the contact portion of the first switch member and the second switch member Contact accuracy (degree of contact freedom) can be significantly increased.

  According to the fourth aspect of the present invention, the bias applied member is a transfer roller disposed opposite to the photosensitive drum, and the transfer roller is brought into contact with the first switch member and the second switch member. A stable transfer bias can always be applied. As a result, it is possible to prevent the transfer bias application accuracy to the transfer roller from being lowered.

  According to the fifth aspect of the present invention, the second switch member is provided on the image forming apparatus main body side, and the bias applied member and the first switch member are attached to the cover member attached to the image forming apparatus main body so as to be opened and closed. When the cover member is closed with respect to the image forming apparatus main body, the first switch member and the second switch member come into contact with each other and a transfer bias is applied to the transfer roller. As described above, even in the configuration in which the first switch member is provided on the cover member side, poor contact between the first switch member and the second switch member can be prevented, so that the design flexibility of the image forming apparatus can be increased. it can.

  Next, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the image forming apparatus 10 includes an image forming apparatus main body 12. The image forming apparatus main body 12 has a plurality of paper feed cassettes 14 arranged in multiple stages. Each sheet cassette 14 stores sheets of different sizes in a stacked state. The image forming apparatus main body 12 houses an image forming section (not shown) including a charger, a developing device, an exposure device, a fixing device, and the like. A method for forming an image on a sheet by an image forming unit including a charger, a developing device, a fixing device, and the like is well known in the art and will not be described.

  An image reading unit 16 that reads an image of a document is provided on the upper part of the image forming apparatus main body 12. An operation unit 18 for executing each operation is provided in the vicinity of the image reading unit 16.

  In this image forming apparatus 10, when a user operates the operation unit 18, image information described in a document is read by the image reading unit 16, and is stored in the paper feed cassette 14 by the image forming unit based on the read data. An image is formed on the paper that was left.

  Further, an opening 22 (see FIG. 5) is formed on the side surface of the image forming apparatus main body 12, and the jam access cover (cover member) 20 is attached so as to be openable and closable with respect to the image forming apparatus main body 12. It has been. When the jam access cover 20 is open with respect to the image forming apparatus main body 12, the opening 22 on the side surface of the image forming apparatus main body 12 is released, and the jam access cover 20 is closed with respect to the image forming apparatus main body 12. Then, the opening 22 on the side surface of the image forming apparatus main body 12 is closed. When the paper is jammed inside the image forming apparatus main body 12, the jammed paper can be easily removed from the opening 22 by opening the jam access cover 20 with respect to the image forming apparatus main body 12. It becomes.

  As shown in FIGS. 2 and 3, a storage case 26 for storing a transfer roller (bias applied member) 24 is attached to the back side (image forming apparatus main body 12 side) of the jam access cover 20. A conductive bearing member 28 is attached to the inside of the storage case 26, and the transfer roller 24 is provided on the bearing member 28 so as to be rotatable.

  A leaf spring-shaped first switch member 30 is attached to the storage case 26. The first switch member 30 has conductivity and elasticity. Here, the shape of the first switch member 30 will be described in detail.

  As shown in FIG. 4, the first switch member 30 includes a plate-like base portion 32. The base portion 32 is formed with two through holes 34 and 36 penetrating in the thickness direction. When the first switch member 30 is attached to the storage case 26, a protrusion (not shown) formed on the side of the storage case 26 is inserted into one through hole 34 from one side, and the other through hole 36 is inserted into the other through hole 36. Another protrusion (not shown) formed on the storage case 26 side is inserted from the opposite direction (the direction opposite to the insertion direction of the protrusion). For this reason, the first switch member 30 is fixed to the storage case 26 in a state of being sandwiched between two protrusions formed on the storage case 26 side like a so-called sandwich. Two groove portions 38 are formed at the side end of the base portion 32. Each groove portion 38 is in contact with a leg portion (not shown) of the bearing member 28. Therefore, the first switch member 30 and the transfer roller 24 are electrically connected via the conductive bearing member 28.

  A first elastic portion 40 is formed at the end of the base portion 32 so as to extend at a predetermined inclination angle with respect to the base portion 32.

  The first elastic portion 40 is formed with a contact portion 42 that contacts a second elastic portion 44 described later so as to extend at a predetermined inclination angle with respect to the first elastic portion 40. A plurality (two in this embodiment) of convex portions 46 are formed on the surface of the contact portion 42. Each convex portion 46 includes a contact plane portion 48 that contacts the second switch member 54 and a pair of elastic support portions 50 that apply an elastic force to the contact plane portion 48. As described above, an elastic force is applied to the contact plane portion 48 of each convex portion 46 by each elastic support portion 50, and an elastic force is applied to the contact portion 42 by the first elastic portion 40 and the second elastic portion 44 described later. Therefore, a double elastic force is applied to the contact flat surface portion 48 of each convex portion 46. In addition, each convex part 46 formed on the surface of the contact part 42 is formed by punching.

  A second elastic portion 44 is formed at the end of the contact portion 42 so as to extend at a predetermined inclination angle with respect to the contact portion 42. An elastic force is applied to the contact portion 42 by the first elastic portion 40 and the second elastic portion 44.

  As described above, the first switch member 30 includes the base portion 32, the first elastic portion 40, the contact portion 42, and the second elastic portion 44, and after the whole is integrally formed, It is formed by bending. The first switch member 30 is made of metal, has conductivity, and also has elasticity.

  Further, as shown in FIG. 5, a photosensitive member, which is a component of the image forming unit, is located inside the image forming apparatus main body 12 at a position facing the transfer roller 24 when the jam access cover 20 is closed. A drum 52 is rotatably provided. An electrostatic latent image is formed on the surface of the photosensitive drum 52, toner is supplied to the electrostatic latent image to be visualized (toner image is formed), and the toner supplied on the electrostatic latent image Is attracted to the transfer roller 24 side, so that the toner adheres to the sheet conveyed between the photosensitive drum 52 and the transfer roller 24.

  Further, a second switch member 54 is provided in the vicinity of one end portion in the axial direction of the photosensitive drum 52. Similar to the first switch member 30, the second switch member 54 is formed of a metal and a leaf spring shape, and has both conductivity and elasticity. The second switch member 54 includes a planar switch body portion 56 with which each convex portion 46 of the contact portion 42 of the first switch member 30 contacts. When the jam access cover 20 is closed with respect to the image forming apparatus main body 12, each convex portion 46 of the contact portion 42 of the first switch member 30 comes into contact with the switch main body portion 56 of the second switch member 54. Yes.

  Further, a power supply unit (power supply means, not shown) is provided inside the image forming apparatus main body 12. The power supply unit can apply a predetermined transfer bias to the second switch member 54. Therefore, when the first switch member 30 and the second switch member 54 come into contact with each other, a predetermined transfer is performed from the power supply unit to the transfer roller 24 via the second switch member 54, the first switch member 30, and the conductive bearing member 28. A bias can be applied.

  Next, the operation of the image forming apparatus 10 of this embodiment will be described.

  As shown in FIGS. 3 and 5, when the jam access cover 20 is closed with respect to the image forming apparatus main body 12 from the state in which the jam access cover 20 is opened with respect to the image forming apparatus main body 12, Each convex portion 46 of the contact portion 42 contacts the switch main body portion 56 of the second switch member 54. At this time, since a predetermined elastic force acts on the contact portion 42 of the first switch member 30 by the elastic portions 40 and 44, the contact portion of the first switch member 30 is applied to the switch body portion 56 of the second switch member 54. A predetermined pressing force is applied from 42. At the same time, since a reaction force acts on the contact portion 42 of the first switch member 30 from the switch body portion 56 of the second switch member 54, the contact portion 42 is bent and deformed.

  At this time, each convex portion 46 formed on the contact portion 42 is in contact with the switch main body portion 56 of the second switch member 54, but each elastic support portion 50 is provided on the contact plane portion 48 of each convex portion 46. A predetermined elastic force is applied. For this reason, a reaction force acts on the contact flat surface portion 48 of each convex portion 46 from the switch main body portion 56 of the second switch member 54, and each convex portion 46 is bent and deformed.

  In this way, the contact flat portion 48 of each convex portion 46 is in contact with the switch main body portion 56 of the second switch member 54 in a state where the double elastic force is applied. The contact pressure can be improved, and the degree of adhesion between the two can be increased. Since the 1st switch member 30 and the 2nd switch member 54 contact via the some convex part 46, both contact points increase. As a result, even when vibration or the like occurs in the image forming apparatus 10, it is possible to prevent poor contact between the first switch member 30 and the second switch member 54.

  Specifically, since the plurality of convex portions 46 are formed on the contact portion 42 of the first switch member 30, even if the contact portion 42 of the first switch member 30 is bent, the posture is not stable. Any one of the plurality of protrusions 46 comes into contact with the switch body 56 of the second switch member 54. Accordingly, the contact accuracy (contact freeness) between the contact portion 42 of the first switch member 30 and the switch main body portion 56 of the second switch member 54 is not affected by the posture and the inclination angle of the contact portion 42 of the first switch member 30. Degree).

  In addition, the elastic force applied by the first elastic part 40 and the second elastic part 44 and the elastic force applied by the pair of elastic support parts 50 act on the contact plane part 48 of each convex part 46. Thereby, the strength of the contact portion 42 of the first switch member 30 can be increased by applying a double elastic force to the contact flat portion 48 of the convex portion 46. As a result, the contact accuracy (contact degree of freedom) between the contact portion 42 of the first switch member 30 and the switch main body portion 56 of the second switch member 54 can be significantly increased.

  In particular, since each convex portion 46 is formed in the contact portion 42 by punching, the strength is higher than that of the conventional technique formed in a comb shape. Thereby, since it can prevent that each convex part 46 bends easily, the poor contact between the 1st switch member 30 and the 2nd switch member 54 can be prevented.

  As described above, since the contact failure between the first switch member 30 and the second switch member 54 can be prevented, a stable transfer bias can always be applied to the transfer roller 24. As a result, it is possible to prevent the transfer bias application accuracy to the transfer roller 24 from being lowered.

  In particular, the second switch member 54 is provided on the image forming apparatus main body 12 side, the transfer roller 24 and the first switch member 30 are provided on the jam access cover 20 side, and the jam access cover 20 is closed with respect to the image forming apparatus main body 12. Sometimes, the first switch member 30 and the second switch member 54 come into contact with each other, and a transfer bias is applied to the transfer roller 24. Thus, even in the configuration in which the first switch member 30 is provided on the jam access cover 20 side, poor contact between the first switch member 30 and the second switch member 54 can be prevented, so that the design of the image forming apparatus 10 can be prevented. You can also increase the degree of freedom.

  In the present embodiment, the configuration in which the plurality of convex portions 46 are formed on the contact portion 42 of the first switch member 30 is shown, but the plurality of convex portions 46 are not the contact portion 42 of the first switch member 30. The second switch member 54 may be formed on the switch body 56 side.

  Moreover, although the structure which attached the 1st switch member 30 to the jam access cover 20 side was shown, if it is a site | part which can contact with a 2nd switch member by operation | movement, the 1st switch member 30 is others You may attach to the part. Further, the configuration using the first switch member 30 as a means for applying the transfer bias to the transfer roller 24 is shown, but the first switch member 30 is not limited to the transfer roller 24 and other components that require a bias. May be electrically connected.

1 is an external view of an image forming apparatus according to an embodiment of the present invention. It is the perspective view seen from the back side of the cover member which constitutes the image forming device concerning one embodiment of the present invention. 1 is an enlarged view of a main part of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a perspective view of a first switch member attached to a cover member constituting the image forming apparatus according to the embodiment of the present disclosure. FIG. 5 is a perspective view showing a second switch member attached to the image forming apparatus main body constituting the image forming apparatus according to the embodiment of the present disclosure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Image forming apparatus main body 20 Jam access cover (cover member)
24 Transfer roller (bias applied member)
30 First switch member 32 Base portion 40 First elastic portion 42 Contact portion 44 Second elastic portion 46 Convex portion 48 Contact plane portion 50 Elastic support portion 52 Photosensitive drum 54 Second switch member

Claims (5)

A bias applied member, a first switch member electrically connected to the bias applied member and having elasticity and conductivity, and a power supply means connected to the first switch member to contact the bias applied member. An image forming apparatus having a second switch member to which an arbitrary bias can be applied,
An image forming apparatus, wherein a plurality of convex portions are formed at a contact portion where the first switch member and the second switch member are in contact with each other. The first switch member includes a base portion that can be attached to another part, a contact portion that contacts the second switch member, and an end portion of the base portion that extends from the base portion and the contact portion. A first elastic part for connecting and applying an elastic force to the contact part, and a second elastic part extending from the contact part and applying an elastic force to the contact part together with the first elastic part,
The image forming apparatus according to claim 1, wherein the convex portion is formed in the contact portion.   The said convex part is comprised by the contact plane part which contacts the said 2nd switch member, and a pair of elastic support part which makes an elastic force act on the said contact plane part, It is characterized by the above-mentioned. The image forming apparatus according to 2. The bias applied member is a transfer roller disposed to face the photosensitive drum,
4. The image forming apparatus according to claim 1, wherein a transfer bias is applied to the transfer roller by contacting the first switch member and the second switch member. 5. The second switch member is provided on the image forming apparatus main body side,
The bias applied member and the first switch member are respectively provided on cover members that are attached to the image forming apparatus main body so as to be openable and closable.
2. The transfer bias is applied to the transfer roller when the cover member is closed with respect to the main body of the image forming apparatus and the first switch member and the second switch member come into contact with each other. 5. The image forming apparatus according to any one of items 1 to 4.

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