JP4185613B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, and a printer, and more particularly to an image forming apparatus.
[0002]
[Prior art]
The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, a printer, and the like. Specifically, a developing unit having a plurality of developing units disposed around a rotation axis is arbitrarily rotated around the rotation axis. The present invention relates to an image forming apparatus provided with a rotary developing device that performs development by moving the developing device to a developing position facing a latent image carrier.
[0003]
Conventionally, as this type of image forming apparatus, for example, in Japanese Patent Application Laid-Open No. 7-325480, a developing unit having a plurality of developing units arranged around a rotation axis is rotated around the rotation axis to arbitrarily In the image forming apparatus provided with the rotary type developing device for performing development by moving the developing unit to the developing position facing the latent image carrier, a power receiving terminal is provided at a predetermined position at the end in the rotational axis direction of the developing unit. A power supply terminal is provided at a predetermined position on the apparatus main body side opposite to the movement path of the receiving terminal by the rotation of the developing unit, and either the receiving terminal or the supplying terminal faces the other It is composed of an advancing / retracting member attached so as to be able to advance / retreat in an energized state, and the advancing / retreating member is brought into contact with the other terminal so that power is supplied to the developing device unit side. Image forming apparatus has been proposed for.
According to this configuration, the terminal member constituted by the advancing / retreating member among the power receiving terminal of the developing unit and the power supply terminal on the apparatus main body side can advance and retreat in a state of being biased toward the other terminal. Therefore, within a certain range, even if the assembly between the developing unit side and the apparatus main body side varies, reliable contact between the two can be obtained.
[0004]
[Problems to be solved by the invention]
However, at the contact portion between the power receiving terminal and the power supply terminal having the above-described configuration, the power receiving terminal is in contact with the power supply terminal while revolving as the entire developer unit rotates. It is conceivable that the contact portion is worn. Further, this wear is considered to occur even when the power receiving terminal itself rotates at the contact portion.
Then, a good power supply cannot be made from the abutted contact portion, and there is a risk of causing a problem on the image. In such a case, conventionally, the power supply terminal has to be replaced.
[0005]
The present invention has been made in view of the above-described problems, and its object is to replace the power supply terminal even if wear that causes a problem on the image occurs in the contact portion with the receiving terminal. It is an object of the present invention to provide an image forming apparatus that can normally supply power without any problems.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, an image forming apparatus according to claim 1 is configured to rotate a developing unit having a plurality of developing units disposed around a rotation axis about the rotation axis, thereby developing an arbitrary developing unit. A rotary developing device that performs development by moving the toner image to a developing position facing the latent image carrier, and a power supply terminal provided on the apparatus main body side is brought into contact with a power receiving terminal provided on the developing unit. in the image forming apparatus configured to supply power to the developing unit side, the contact between the power receiving terminal of the power supply terminals and rotatably constructed in the axis itself of the center the power supply terminal It is characterized in that the part used for the item can be changed.
[0007]
Here, in the above-mentioned Japanese Patent Application Laid-Open No. 7-325480, no contact position between the power receiving terminal and the power supply terminal is defined.
The image forming apparatus according to claim 1, to be able to change the position of using the power supply terminals and rotatably constructed by their center axis the contact of the power receiving terminals in the power supply terminals, the power supply terminal When the contact portion with the power receiving terminal is worn, the power receiving terminal can be brought into contact with another position of the power supply terminal. As a result, the power supply terminal can be used continuously without replacement.
[0008]
According to a second aspect of the present invention, there is provided the image forming apparatus according to the first aspect, wherein a power receiving terminal is provided at a predetermined portion of the end of the developing unit in the rotational axis direction, and the receiving terminal is revolved by the rotation of the developing unit. An advancing / retracting member provided with a power supply terminal at a predetermined location on the apparatus main body side facing the path and attached so that either the receiving terminal or the supplying terminal can be advanced or retracted while being biased toward the other The image forming apparatus is configured to supply power to the developing device unit by contacting the advance / retreat member with the other terminal, the tip of the power supply terminal being directed toward the developing unit. The projecting shape is configured such that the contact position of the receiving terminal on the power supply terminal is located farther from the developing unit side than the tip of the power supply terminal. It is an butterfly.
[0009]
3. The image forming apparatus according to claim 2, wherein the power receiving terminal is brought into contact with a position farther from the developing unit side than the tip of the power supply terminal, and the power receiving terminal is located on a side surface other than the tip of the power supply terminal. Make contact. As a result, when the abutting portion is worn, the power supply terminal surface is not worn by rotating the power supply terminal so that the contact position of the power receiving terminal with the power supply terminal changes. It becomes possible to make it contact | abut.
[0010]
The image forming apparatus according to claim 3 is the image forming apparatus according to claim 2, when the upper Symbol power supply terminals and the receiving terminals are contact state, toward the developing unit side of the power source supply terminal The power supply terminal is provided so that the protruding tip is displaced inward or outward from the revolution trajectory of the receiving terminal due to the rotation of the developing unit.
[0011]
The image forming apparatus according to claim 3, wherein the power supply terminal is arranged such that a tip of the power supply terminal protruding toward the developing unit is displaced inward or outward from a revolution trajectory of the receiving terminal due to rotation of the developing unit. Since it is provided, the side surface of the power supply terminal can be brought into contact with the power receiving terminal. As a result, the power supply terminal surface that is not worn by rotating the power supply terminal can be brought into contact with the power supply receiving terminal.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment in which the present invention is applied to a color electrophotographic printer (hereinafter referred to as a printer) as an image forming apparatus will be described below.
FIG. 1 is a schematic configuration diagram of a printer according to the present embodiment. First, an outline of the entire printer will be described. In FIG. 1, a photosensitive drum 1 as a latent image carrier is uniformly charged by a charging charger 2 as a uniform charging means while being rotated in the direction of arrow A, and then image information is obtained by a laser optical device 3. And an electrostatic latent image is formed on the surface. Here, the image information to be exposed is single-color image information obtained by separating a desired full-color image into yellow, magenta, cyan, and black color information. The electrostatic latent image formed on the photosensitive drum 1 is developed with yellow, magenta, cyan, and black toners as predetermined developers by a rotary developing device 4 described later. Each color image is formed.
[0015]
Each color image formed on the photosensitive drum 1 is primary, yellow, magenta, cyan, and black for each monochrome color on an intermediate transfer belt 5 that rotates in the direction of arrow B in the drawing in synchronization with the photosensitive drum 1. The images are sequentially superimposed and transferred by the transfer charger 6. The yellow, magenta, cyan, and black images superimposed on the intermediate transfer belt 5 are transferred from the double-sided copying / automatic sheet feeding cassette 7 or the manual sheet feeding tray 7a through the sheet feeding rollers 8 and 8a and the registration roller 9. Are collectively transferred by the secondary transfer charger 11 onto the transfer paper 10 conveyed to the front. After the transfer, the transfer paper 10 is fixed with a toner image by a fixing device 12 and discharged out of the apparatus as a full color print.
[0016]
The toner on the photoconductive drum 1 that has not been transferred onto the intermediate transfer belt 5 is removed from the photoconductive drum 1 by the photoconductor cleaner 13, and the toner on the intermediate transfer belt 5 that has not been transferred onto the transfer paper 10. The toner is removed from the intermediate transfer belt 5 by the intermediate transfer belt cleaner 14.
[0017]
Next, the rotary developing device according to this embodiment will be described. 2 is an exploded perspective view of the developing device, FIG. 3 is a cross-sectional view showing an internal structure of the developing unit 40 of the developing device, and FIG. 4 is an explanatory diagram of a communication structure between the developing unit 40 and the toner container unit 45. 5 is a perspective view from the front showing the drive system of the developing unit 40 and the like.
Referring to FIG. 2, the rotary developing device includes, for example, black, cyan, yellow, and magenta developing devices formed therein, and the outer periphery of the printer body that is rotatably mounted around the central axis is substantially cylindrical. Developer unit 40 and four developer containers 41, 42, 43, 44 corresponding to the respective developer units one by one and containing toners of black, yellow, magenta, and cyan, respectively, and the developer unit 40, a toner container unit 45 which is attached so as to be substantially coaxial on the front side in the direction of the central axis thereof, and rotates integrally with the developing unit 40 around the central axis, and the developer unit 40 and the toner container Storage unit slidable in the printer main body substantially parallel to the central axis line with the unit 45 (hereinafter referred to as a revolver developing unit) supported. 46, and a cover 47 provided so as not to rotate in the housing base before the support plate 48 so as to cover the toner container unit 45.
[0018]
The revolver developing unit supports the disk-shaped front end wall 50 of the developing unit 40 with, for example, two supporting rollers 49 rotatably attached to the front supporting plate 48 of the accommodating table 46, and the developing unit 40 The central body 52 of the front end taper projecting from the center of the disc-shaped rear end wall 51 is rotatably supported by the central shaft insertion hole 54 formed in the rear side plate 53 of the main body. For example, as shown in FIG. 1, the rotation axis thereof is positioned at a position parallel to each other in the same horizontal plane as the rotation axis of the photosensitive drum 1, and is rotatable.
[0019]
First, the details of the mechanism for rotatably supporting the revolver developing unit will be described with reference to FIG. In FIG. 2, the storage platform 46 includes a front support plate 48, a rear support plate 55, a side cover 59 having front and rear ends fixed to both support plates and reinforced by connecting rods 56, 57, and 58. Have The front support plate 48 is formed with an insertion hole 60 into which the revolver developing unit can be inserted, and in addition to the support roller 49, a toner supply roller driving motor 61 provided in the toner container unit 45, and the motor 61 A gear train driven by a motor 61 is attached. An intermediate plate 63 is attached to the connecting rods 56 and 57 in the vicinity of the rear support plate 55, and a positioning pin 63b that fits into a positioning hole 63a formed in the rear plate of the main body projects into the intermediate plate 63. It is installed. A proximal end portion of a bracket 64 holding a rotary positioning roller 66 is attached to a positioning pin portion between the intermediate plate 63 and the rear support plate 55 so as to be swingable. The bracket 64 is urged by a spring 67 in such a direction that the roller 66 is fitted into a recess 65 formed at a predetermined position on the peripheral surface of the developing unit rear end wall 51 (see also FIG. 5).
[0020]
The main body front side plate 68 is formed with an insertion hole 69 or the like into which the storage table 46 carrying the revolver developing unit can be inserted, and the storage table 46 is interposed between the main body front side plate 68 and the main body rear side plate 53. The upper and lower guides 70 and 71 for slidably supporting are hung. Guided portions 72 and 73 are provided at the upper end and the side of the side cover 59 of the receiving table as the receiving table portion guided by the guides 70 and 71, respectively. A guide pin groove 75 into which a guide pin 74 planted upward in the guide 71 enters is formed on the lower surface portion. The pin groove 75 allows the receiving table 46 to escape away from the photosensitive drum 1 when the receiving table 46 is inserted into or pulled out from the printer body, and at a predetermined position relatively close to the photosensitive drum 1 when the insertion is completed. In order to be able to guide the revolver developing unit, only a predetermined portion on the front side is bent from the middle so that it is closer to the photosensitive drum 1 than the rear portion.
[0021]
In the support mechanism of the revolver developing unit described above, when the main body of the storage base 46 is inserted, the tapered tip end portion of the positioning pin 63b projecting from the intermediate plate 63 is immediately before the completion of the insertion of the storage base into the printer main body. The positioning plate 63 enters the positioning hole 63a of the side plate 53, and when the insertion is completed, the rear support plate 55 and the bracket 63 of the storage base 46 are accurately positioned in the main body. On the other hand, in the pulled-out state of the storage base 46, the rear end portion of the revolver developing unit supported by the rear plate 53 of the storage base 46 is centered on the central axis 52 having a tapered tip immediately before the main body insertion of the storage base 46 is completed. The shaft is lifted as it gradually enters the shaft insertion hole 54, and is completely lifted from the rear support plate 55 when the insertion is completed. The front support plate 48 of the storage base 46 is fixed to the main body front side plate 68 with screws 76 or the like after the insertion of the storage base 46 into the main body is completed.
As a result, the revolver developing unit is supported at the front end portion by the support roller 49 of the front support plate 48 that is accurately positioned on the main body, and is pivotable to the main body rear side plate 53 via the center shaft 52. The part is positioned and can be rotated.
[0022]
A revolver driving gear 78 driven by a revolver rotating motor such as a stepping motor (not shown) is attached to the main body rear side plate 53 for revolver developing unit rotation driving. This meshes with the revolver input gear 79 having substantially the same diameter as the rear end plate 51 fixed to the rear surface of the rear end plate of the developing unit 40 by screws or the like, so that the revolver developing unit is rotated ( (See also FIG. 5). Further, a development drive gear 81 driven by a development drive motor (not shown) is also attached to the main body rear side plate 53 in order to drive a developing roller 84 and the like in the developing unit 40 described later (see also FIG. 5). ).
[0023]
Next, the developing unit 40 will be described with reference to FIGS. In FIG. 3, the developing unit 40 includes a partition wall provided between the above-described substantially disc-shaped front and rear end plates 50 and 51. The partition wall includes a hollow cylindrical portion 82 into which a cylindrical black toner bottle containing black toner can be inserted, and extends radially from the hollow cylindrical portion 82 so that the space around the hollow cylindrical portion 82 is substantially mutually circumferential. It comprises developing device casing parts 83, 83C, 83M and 83Y which are divided into four developing chambers of the same type. In each of these developing chambers, a two-component developer composed of a carrier as a developer and toner of each color is accommodated. In the example shown in the figure, the developing position of the black developing device containing black toner and carrier is at the developing position facing the photosensitive drum, and the yellow developing device containing yellow toner and carrier in the counterclockwise order in the figure. A developing chamber, a developing chamber of a magenta developing device containing magenta toner and a carrier, and a developing chamber of a cyan developing device containing cyan toner and a carrier.
[0024]
Here, since the internal structures of the four developing chambers are exactly the same, the internal structure will be described below with reference to the black developing chamber in the developing position in FIG. 3 as an example, and the internal structures of the other developing chambers correspond. As the reference numerals of the members, the same numerals as those in the black developing chamber are attached with the suffixes Y, M, and C in order to distinguish the developing chambers of yellow, magenta, and cyan, and the description thereof is omitted.
[0025]
In the black developing device in the developing position in the figure, an opening toward the photosensitive drum 1 is formed in the developing device casing 83, and a developing roller 84 is provided in the developing chamber so that a part is exposed through the opening. Is provided. Further, a developing blade 84 which is carried on the developing roller 84 and regulates the amount of developer conveyed to the portion facing the photosensitive drum 1 in the developing chamber, and the developing which is restricted by the doctor blade 85 and is held in the developing chamber. An upper conveying screw 86 for conveying a part of the agent along the central axis direction from the rear to the front, a guide 87 thereof, and an agitation paddle 88 for agitating the developer in the developing chamber are provided. The stirring paddle 88 includes a hollow cylindrical portion 89 in which a plurality of developer discharge holes 89 a are formed across the width direction of the developing roller 84, and a plurality of stirring plate portions 90 extending radially from the peripheral surface of the hollow cylindrical portion 89. The hollow cylindrical portion 89 accommodates a lower conveying screw 91 that conveys the developer in the direction opposite to the upper conveying screw 86 along the central axis direction. The developer casing below the lower conveying screw 91 has a developer discharge port used as a deteriorated developer discharge port and an unused developer (toner mixed) input port when the developer is changed due to deterioration in the development chamber. An outlet 92 is formed. The discharge port 92 is covered from the outside by a cap 93 attached with a screw 94.
[0026]
In FIG. 4, the front end portions of the upper and lower transport screws 86 and 91 extend to the outside of the front end wall 50 of the developing unit, and the developer transported by the upper transport screw 86 to the extended portion is transported downward. A dropping part 96 for dropping the screw 91 by its own weight is provided on the screw 91. The developer regulated by the doctor blade 85 and conveyed to the front side by the guide 87 and the upper conveying screw 86 falls on the lower conveying screw 91 via the dropping portion 96, and the developing roller 84 is developed by the lower conveying screw 91. And then discharged into the developing chamber from the developer discharge port of the stirring paddle hollow cylindrical portion. Thereby, so-called lateral stirring of the developer in the developing chamber is performed. Further, the developer discharged from the developer discharge port of the hollow cylindrical portion 82 of the stirring paddle 88 to the developer reservoir in the lower portion of the developing chamber is stirred by the stirring plate portion by the rotation of the stirring paddle 88, whereby vertical stirring is performed. Done. Further, the front end portion of the lower conveying screw 91 extends further to the front side than the dropping portion 96, and each toner receiving case 91Y, M, C, 110 provided corresponding to each developing chamber of the toner container unit 45 is provided. It extends to the inside, specifically below the toner supply roller 97 provided in the case.
[0027]
In the example of FIG. 3, for example, as shown for the yellow developing device, the front and rear end walls that support the developing roller 84Y and the doctor blade 85Y are configured as a small end wall 104 that can be separated from other front and rear end walls. Has been. As a result, when the developing chamber is cleaned and parts are replaced, the developing roller 84Y and the doctor blade 85Y are removed together with the small end wall portion 104 so that the developing chamber can be easily accessed.
[0028]
Next, the toner container unit 45 will be described with reference to FIG. 2 again. The toner container unit 45 includes a disk-shaped unit face plate 108 and a total of four toner receiving cases 91Y, M, C, 110 attached to the front face of the face plate so as to correspond to each developing device on a one-to-one basis. Have The unit face plate 108 is formed with a circular through hole (not shown) through which a cylindrical black toner container can be passed in the center thereof, and each of the toner receiving cases 91Y, 91M, 91C, 110 is It escapes from this through-hole and is attached.
[0029]
Of these four toner receiving cases 91Y, 91M, 110C, 110, the three color toner receiving cases 91Y, 91M, 91C corresponding to the respective color developing units have their corresponding developing chambers located at the developing position. A toner receiving port facing upward is formed. The color toner containers 42, 43, 44 having the same color and containing the color toner are mounted on the mounting portion around the toner receiving port with the toner discharge port facing downward in the revolver developing unit rotation axis direction. It is attached by a slide.
[0030]
On the other hand, the black toner receiving case 110 corresponding to the black developing device has substantially the same shape as the entire peripheral wall shape of the color toner receiving cases 91Y, 91, and C attached to the color toner receiving cases 42, 43, and 44. It has a peripheral wall shape. A toner receiving port having a shape corresponding to the toner discharge port of the black toner container 41 is formed at a portion facing the center line of the revolver developing unit in the peripheral wall portion having the same shape as the color toner receiving case.
[0031]
The black toner container 41 has a cylindrical shape, and a toner discharge port is formed in a peripheral wall portion at one end portion in the longitudinal direction, and a protrusion for feeding toner is formed on the inner peripheral surface portion from the other end portion to the toner discharge port. It is spirally formed on the side. The spiral ridges feed the stored toner from the rear end to the front end while the unit is rotating integrally with the revolver developing unit, and receive the black toner from the toner discharge port. The toner is supplied into the toner receiving port of the case. Such a black toner container 41 enters the hollow cylindrical portion 82 of the developing unit 40 through the central portion of the toner container insertion notch 47a formed in the cover 47 described above. For example, the toner container unit 45 is attached in a state where the front end part is substantially flush with the front surface of the front end wall part of each case.
[0032]
Then, as shown in FIG. 4 taking the black toner receiving case 110 as an example, a toner replenishing roller 97 is provided in each of the four toner receiving cases 91Y, 91M, C, 110. The toner replenishing roller 97 has a front end wall portion and a unit face plate of the case so as to be positioned almost directly above the portion where the lower conveying screw 91 extends into the case when the corresponding developing chamber is located at the developing position. 108 is pivotally supported. A shaft end portion of the toner replenishing roller 97 supported by the unit face plate 108 passes through the face plate 108 and protrudes toward the developing device unit 40, and a gear 197 is fixed to the protruding end portion. A drive input replenishment input gear (not shown) that meshes with the gear 197 is rotatably provided on the surface of the unit face plate 108 on the developing unit side. Of the replenishment input gears provided for each toner replenishment roller 97, the one corresponding to the toner replenishment roller 97 in the case corresponding to the developing device at the development position is a gear driven by the replenishment motor 61 described above. (See FIG. 2) and can be rotated by the motor 61. The toner dropped onto the lower conveying screw 91 by the rotation of the toner replenishing roller 97 is taken into the developer dropped from the upper conveying screw 86 halfway, and conveyed to the developing chamber by the lower conveying screw 91 while being mixed with each other. The toner density of the developer in the developing chamber is increased. Toner replenishment control is performed by drive control of the replenishment motor 61 that drives the toner replenishment roller 97.
[0033]
Next, a mechanism for rotationally driving a rotating body such as a developing roller in the developing unit 40 will be described with reference to FIG. The illustrated gears are provided on the rear end wall 51 of the developing unit 40, specifically on the rear side of the revolver input gear 79 fixed to the rear end wall 51. That is, the developing roller gear 98 is fixed to the shaft end portion of the developing roller 84 that penetrates the rear end wall 51 and the like and protrudes to the rear side of the revolver input gear 79. Upper and lower conveying screw gears 99 and 100 are fixedly provided at the shaft ends of the upper and lower conveying screws 86 and 91 protruding to the rear side. In the illustrated example, the idler gear 101 meshed with the developing roller 84 gear and the lower conveying screw gear 100 and the development output gear 81 attached to the main body rear side plate 53 and driven by the development driving motor 80 are meshed. A developing input gear 95 is attached to the back side of the rear end wall 51 of the developing unit. These gears are connected to the developing output gear 81 on the main body side and the revolver developing unit when the revolver developing unit provided on the rear end wall side is carried on the storage base 46 and inserted into the printer main body as described above. Side development input gear 95 meshes. At the same time, the revolver input gear 79 on the revolver developing unit side meshes with the revolver output gear 78 on the main body side.
[0034]
In FIG. 5 in which the above meshing has been realized, during development, the development output gear 81 is driven in the direction indicated by the arrow A in the figure, and the upper and lower conveying screw gears 99 and 100 are rotated via the development input gear 95 meshed therewith. Then, the upper and lower conveying screws are driven to rotate. Further, the developing roller gear 98 is rotated through the developing input gear 95, the lower conveying screw gear 100, and the idle gear 101, so that the developing roller 84 is rotationally driven.
[0035]
When the developing device to be used is switched, the revolver output gear 79 driven by the revolver driving motor is rotated in the direction of arrow B shown in FIG. 5 to rotate the revolver developing unit in the direction of arrow C. The developing unit positioned at the developing position is switched, and the positioning roller 66 is inserted into and fitted into a concave portion 65 formed at a predetermined portion of the peripheral surface portion of the rear end wall 51 of the revolver developing unit to position the revolver developing unit. To do. If the development drive gear 81 is rotated in the direction of arrow A after this positioning, a rotational moment indicated by arrow D in the figure acts on the revolver development unit. Therefore, the shape of the recess 65 and the force of the spring 67 that biases the rotation positioning roller 66 are set so that the revolver developing unit can be positioned against this rotation moment.
[0036]
Next, a configuration for applying a developing bias from the main body side to the developing roller 84 in the revolver developing unit will be described. FIG. 6 is an explanatory view showing a contact / separation mechanism of the rod terminal 106 for applying the developing bias to the end portion of the developing roller shaft 98a. As shown in FIG. 6, a rod-like terminal 106 connected to a bias circuit 105 is fixed to a fixed position of the main body rear side plate 53 facing the end of the developing roller shaft 98a of the developing unit located at the developing position by a bracket 107 by a storage base slide direction. And is urged to be pushed forward by a spring 107a as urging means.
With this configuration of developing bias application, the rod-shaped terminal 106 is brought into contact with the end of the developing roller shaft 98a by the spring 107a, so that reliable bias application is possible. Further, since the rod-like terminal 106 can be moved back and forth, the driving load of the revolver developing unit can be reduced.
[0037]
Here, when bias is applied with the above-described configuration, the end of the developing roller shaft 98a is in contact with the rod-shaped terminal 106 while rotating, and thus the rod-shaped terminal 106 may be worn. If it continues to be used as it is, there is a risk that bias application cannot be performed satisfactorily. For this reason, it is conceivable to replace the rod-shaped terminal 106 as appropriate. However, if the rod-shaped terminal 106 is replaced every time it is worn, the life of the rod-shaped terminal 106 is shortened. In the present embodiment, the bias application can be performed satisfactorily without exchanging the rod-shaped terminal 106. Below, the characteristic part of this embodiment is demonstrated.
[0038]
In FIG. 6, the shaft end portions of the rod-shaped terminal 106 and the developing roller 84 are formed in a hemispherical tip. Further, the center axis position of the rod-like terminal 106 is shifted from the locus of the developing roller shaft 98a by the rotation of the revolver developing unit. Thus, the developing roller shaft 98a end contact position on the surface of the rod-shaped terminal 106 is a position S that is shifted to the revolver developing unit side with respect to the shaft l of the rod-shaped terminal. Further, the rod-like terminal is attached to the bracket 107 so as to be rotatable in the circumferential direction.
With this configuration, when the contact position S of the rod-shaped terminal with the end portion of the developing roller shaft 98a is worn by the rotation of the developing roller shaft 98a and the bias application is hindered, the rod-shaped terminal 106 is manually moved around the shaft l, for example, manually. The region of the surface of the rod-shaped terminal 106 that is not worn is brought into contact with the end portion of the developing roller shaft 98a. Thereby, it is possible to favorably apply the bias again without exchanging the rod-shaped terminal 106.
The rotation angle of the rod-shaped terminal 106 is not limited to 180 degrees, and may be any number of times as long as the end portion of the developing roller shaft 98a can abut on the region where the rod-shaped terminal 106 is not worn.
According to the above configuration, various positions on the surface of the rod-shaped terminal 106 can be used for bias application by contacting the end portion of the developing roller shaft 98a, so that the life of the rod-shaped terminal 106 can be extended. In addition, it is possible to prevent the occurrence of defects on the image caused by continuing to use the rod-shaped terminal 106 with advanced wear.
[0039]
【The invention's effect】
According to the image forming apparatus of the first, second, and third aspects, the power supply terminal can be easily rotated even if wear that causes a problem on the image occurs in the contact portion between the power supply terminal and the receiving terminal. With the configuration, it is possible to change the portion used for contact with the power receiving terminal in the power supply terminal, and there is an excellent effect that normal power supply can be performed without replacing the power supply terminal. .
[0040]
In particular, according to the image forming apparatus of the second aspect, it is possible to easily displace the contact position of the power supply terminal with the power supply terminal by rotating the power supply terminal.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a copier according to an embodiment.
FIG. 2 is an exploded perspective view of a rotary developing device of the copier.
FIG. 3 is a cross-sectional view of a developing unit of the rotary developing device.
FIG. 4 is an explanatory diagram of a communication structure between a developing device and a toner container in the rotation type developing device.
FIG. 5 is a front perspective view showing a driving system of the developing unit and the like.
FIG. 6 is an explanatory view showing a contact / separation mechanism of a developing bias applying rod-shaped terminal to a developing roller shaft end.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Photosensitive drum 4 Rotating type developing device 40 Developing unit 41 Black toner container 42 Yellow toner container 43 Magenta toner container 44 Cyan toner container 45 Toner container unit 98a Developing roller shaft 105 Bias circuit 106 Rod terminal 107 Bracket 107a spring

Claims (3)

Development is performed by rotating a developing unit having a plurality of developing units disposed around the rotation axis about the rotation axis and moving any developing unit to a development position facing the latent image carrier. An image forming apparatus comprising a rotary developing device and configured to supply power to the developer unit side by bringing a power supply terminal provided on the apparatus main body side into contact with a power supply receiving terminal provided on the developer unit In
An image forming apparatus characterized in that to be able to change the location to be used for contact between the power receiving terminal of the power supply terminals and rotatably constructed in the axis itself of the center the power supply terminal. The image forming apparatus according to claim 1.
A power receiving terminal is provided at a predetermined location on the end of the developing unit in the rotation axis direction, a power supply terminal is provided at a predetermined location on the apparatus main body facing the revolution path of the receiving terminal by rotation of the developing unit; and The developing terminal is configured by an advancing / retracting member attached so that either the receiving terminal or the supply terminal is urged toward the other while being urged toward the other, and the advancing / retreating member is brought into contact with the other terminal. An image forming apparatus configured to supply power to a unit side,
The power supply terminal has a shape with a tip projecting toward the developing unit side, and the contact position of the power supply terminal with the receiving terminal is farther from the development unit side than the power supply terminal tip. An image forming apparatus configured to be positioned. The image forming apparatus according to claim 2.
When the upper Symbol power supply terminal and the receiving terminal is in contact state, from the revolution locus of the receiving terminal tip projecting toward the developing unit side of the power source supply terminal is due to the rotation of the developing unit An image forming apparatus comprising the power supply terminal so as to be displaced inward or outward.

Images