JP2007183305A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus in which large toner cartridge capacity can be attained by a simple configuration and rotation control of a development rotary is facilitated. <P>SOLUTION: The color printer has the development rotary 50, which holds a plurality of developing units 51 at regular intervals in the circumferential direction of a support shaft 61 and can be intermittently rotated to a developing area 11 around the support shaft 61 and to which toner cartridges 55 for supplying toner to the corresponding developing units 51 are freely removably attached. In the color printer, the development rotary 50 has, at both ends in an axial direction, support plates for supporting the developing units 51. The bottom of the toner cartridge 55K is disposed on a shaft center part between the support plates to increase the capacity of the toner cartridge 55K. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus such as a copying machine or a printer that forms a color image.

  In recent years, in the field of image forming apparatuses such as copiers and printers using electrophotography, in order to support the formation of color images, each of the photosensitive drums supports yellow, magenta, cyan, and black. There has been provided a developing rotary that holds the developing means containing the toner at predetermined intervals in the circumferential direction of the support shaft. The developing rotary is driven to rotate intermittently around the support shaft, and each developing means is switched to the developing region for development every rotation of the photosensitive drum. Each developing unit includes a toner cartridge containing toner of a predetermined color, and is configured to be replaced with a new toner cartridge when the toner in the cartridge is consumed.

  By the way, in a color-compatible image forming apparatus, the formation frequency of a monochrome image is usually high, and the consumption amount of black toner increases. Therefore, in Patent Document 1, the color developing means are arranged on the developing rotary at equal intervals of 90 ° or less, and the black developing means is arranged in almost half the space of the developing rotary. A developing device with an increased capacity is disclosed.

However, in the developing device described in Patent Document 1, the four developing means are arranged on the developing rotary so as not to be evenly arranged on the circumference, so that the configuration becomes complicated and the rotation control of the developing rotary at the time of development can be performed. There has been a problem that the rotation control of the developing rotary becomes complicated when the toner cartridge is replaced. In addition, there is a problem that a large take-out space for replacing a large-capacity toner cartridge is required.
JP-A-8-137172

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus capable of realizing a large capacity toner cartridge with a simple configuration.

  Another object of the present invention is to provide an image forming apparatus that achieves the above-mentioned object and facilitates rotation control of the developing rotary.

  In order to achieve the above object, the present invention is configured to hold a plurality of developing means at a predetermined interval in the circumferential direction of a support shaft and to rotate intermittently around the support shaft to a developing region, and to develop each of the developing devices. In the image forming apparatus including a development rotary in which a toner cartridge that replenishes toner for each unit is detachably attached, the development rotary includes support members that support the plurality of development units at both ends in the axial direction. It is characterized in that at least one bottom of the toner cartridge is disposed in an axial center portion between the members.

  In the image forming apparatus according to the present invention, since the bottom portion of at least one toner cartridge is disposed at the shaft center portion between the support members provided at both ends in the axial direction of the developing rotary, in other words, the shaft center portion is hollow. Since the bottom of at least one toner cartridge extends into the cavity, the capacity of the toner cartridge can be easily increased by the extended amount, and the outer diameter of the developing rotary does not increase.

  In the image forming apparatus according to the present invention, each of the plurality of developing units may include a housing, and a support member for the developing rotary may be fixed to both ends of the housing. The plurality of developing means are preferably arranged at equal intervals in the circumferential direction around the shaft portion of the developing rotary. The developing rotary may be rotated intermittently at equal intervals during development or replacement of the toner cartridge. The rotation control during development and replacement is the same, and rotation control of the developing rotary is facilitated.

  Further, the toner cartridge can be configured to have different depth dimensions from the surface of the development rotary. A toner cartridge having a preferable capacity can be combined according to the depth dimension. Moreover, since only the depth is different and the outer shape is the same, the space for attaching and detaching can be shared, and even a large capacity toner cartridge does not require a large space for detaching and attaching.

  Further, the toner cartridge is preferably provided with a lock mechanism at the time of mounting near the surface of the developing rotary. Lock / unlock operability is improved, and a common lock mechanism can be employed even for toner cartridges having different depths.

  Embodiments of an image forming apparatus according to the present invention will be described below with reference to the accompanying drawings.

(Schematic configuration of color printer)
FIG. 1 shows a schematic configuration of a color printer 1 which is an embodiment of an image forming apparatus. The color printer 1 generally includes a photosensitive unit 10, a developing rotary 50, an intermediate transfer unit 20, a laser scanning unit 30, a fixing unit 35, and a paper feeding unit 40.

  The photoreceptor unit 10 includes a photoreceptor drum 11 and a charger 12. The development rotary 50 has black, cyan, magenta, and yellow development devices 51 (51K, 51C, 51M, and 51Y) arranged at equal intervals of 90 ° around the support shaft 61 so as to be integrally rotatable. Is. The intermediate transfer unit 20 includes an intermediate transfer belt 21 that is held endlessly by a driving roller 22, a driven roller 23, a tension roller 24, and a winding roller 25, and includes a primary transfer roller 26.

  The image is formed by a four-cycle method (a method in which a one-color image is formed by four rotations of the photosensitive drum 11). That is, for each rotation of the photosensitive drum 11, an image for each color is exposed from the laser scanning unit 30 to the photosensitive drum 11 (formation of an electrostatic latent image), and the development rotary 50 is intermittently moved by 90 °. It is rotated and developed (toner image) by the developing device 51 of each color. This toner image is primarily transferred onto the intermediate transfer belt 21 by an electric field applied from the primary transfer roller 26 for each color, and four color images are superimposed on the intermediate transfer belt 21.

  On the other hand, the paper is fed one by one from the paper feed unit 40 by the paper feed roller 41, passes through the pair of transport rollers 42, and is supported by the intermediate transfer belt 21 and the secondary transfer roller 27 supported by the drive roller 22. Then, the composite image is secondarily transferred from the intermediate transfer belt 21 by the electric field applied from the secondary transfer roller 27. Thereafter, the fixing unit 35 heats and fixes the toner on the sheet, and the sheet is discharged from the discharge roller pair 5 onto the sheet tray 6.

  The configuration and operation of each image forming unit are well known in the art and will not be described in detail.

(Development rotary configuration)
Here, the configuration of the development rotary 50 will be described. Each developing device 51 includes a developing roller 52 that supplies toner to the photosensitive drum 11, and the developing roller 52 is switched to a position facing the developing area 11 a of the photosensitive drum 11 during development. Further, the developing rotary 50 is provided with a toner cartridge 55 (55K, 55C, 55M, 55Y) containing toner of a color corresponding to each developing device 51. Each toner cartridge 55 replenishes each developing device 51 with an appropriate amount of toner from its opening 56. Note that toner replenishment control and a mechanism for agitating / conveying the replenished toner to the developing roller 52 are well known, and the description thereof is omitted.

  Further, as shown in FIG. 2, the printer main body can be maintained inside the main body by opening the covers 2 and 3 in the directions of arrows a and a ′. Is detachable in the directions of arrows b and b ′.

  As shown in FIG. 3, the developing rotary 50 includes support plates 60, 60 that support the housing 53 of each developing device 51 at both ends in the axial direction, and the support plates 60, 60 are screws 62 at both ends of the housing 53. It is fixed at. In FIG. 3, the toner cartridge 55 is not shown. That is, the developing devices 51 are integrated by the support plates 60 and 60 at equal intervals of 90 °. A space between the housings 53 is a space for loading the toner cartridge 55, and a space is also provided in the axial center portion. A support shaft 61 is attached to the support plate 60, and the developing rotary 50 is rotationally driven in the direction of the arrow c with the support shaft 61 as a fulcrum.

  FIG. 4 shows a schematic configuration of the developing rotary 50 with the toner cartridge 55 removed. The developing devices 51K, 51Y, 51M, and 51C have the same outer shape, and the arrangement angle is θ1 = θ2 = θ3 = θ4.

  FIG. 5 shows a schematic configuration of various toner cartridges 55a to 55e mounted in combination with the developing rotary 50. The toner cartridges 55a to 55e have different depth dimensions and different toner storage amounts.

  FIG. 6A shows a state in which a large-capacity cartridge 55c for black toner and a medium-capacity cartridge 55b for other color toners are combined and mounted on the development rotary 50. In this case, the black toner cartridge 55c (55K) is shown. Only the large capacity cartridge is used, and the other medium capacity cartridges 55b (55C, 55M, 55Y) have the same capacity as the conventional one.

  FIG. 6B shows a state in which a maximum capacity cartridge 55d for black toner and a small capacity cartridge 55a for other color toners are combined and mounted on the development rotary 50. In this case, a large capacity cartridge 55d for black toner is used. The bottom of (55K) has entered the space of the opposing toner cartridge 55M. Note that a medium capacity toner cartridge 55b can be attached to the developing devices 51C and 51Y.

  FIG. 6C shows a state in which a toner cartridge 55e having a tilted bottom is attached to each developing device 51. In this case, both black and each color toner have the same capacity, but are conventionally used. Since the bottom portion of the toner cartridge 55e is disposed up to the shaft center portion that has not been present, the toner storage amount increases.

(Removing and attaching the toner cartridge)
As shown in FIG. 2, the toner cartridge 55 can be detached from the developing rotary 50 with the covers 2 and 3 opened. In this case, the developing rotary 50 is rotated by 90 ° in the direction of arrow c, the toner cartridge 55 to be replaced is set at the position shown in FIG. 2, the toner cartridge 55 is pulled out in the direction of arrow b ′, and a new toner cartridge is drawn. Is inserted in the direction of arrow b.

  As shown in FIG. 7, each toner cartridge 55 has a lock mechanism 70 attached to the surface portion of the developing rotary 50. The lock mechanism 70 is provided with a cam 73 at the base of a lever 71 that is rotatable with a pin 72 as a fulcrum. When the lever 71 is positioned parallel to the surface (see FIG. 7A), the protrusion of the toner cartridge 55 is provided. The part 57 is fitted into the hole 54a of the lock plate 54 provided in the developing rotary 50, and is maintained in the locked state. When the lever 71 is raised (see FIG. 7B), the cam 73 presses the upper portion of the lock plate 54, the projection 57 is released from the engagement with the hole 54a, and the toner cartridge 55 is pulled out. Is possible.

  In the color printer 1 described above, the bottom portion of the toner cartridge 55 is disposed in the axial center portion between the support plates 60 and 60 provided at both axial end portions of the developing rotary 50. In other words, the axial center portion is hollow. Since the bottom of the toner cartridge 55 is extended in the cavity, the capacity of the toner cartridge 55 can be easily increased by the extended amount. Moreover, the outer diameter of the development rotary 50 does not increase.

  Further, the developing devices 51 are arranged at equal intervals in the circumferential direction around the support shaft 61 of the developing rotary 50 in spite of different capacities of the toner cartridges 55. Therefore, the development rotary 50 may be intermittently rotated by 90 ° during development, and no special control due to the difference in interval is necessary. Even when the toner cartridge 55 is replaced, the developing rotary 50 may be intermittently rotated by 90 ° at regular intervals to set the toner cartridge 55 at the removal position, and the rotation control during development and replacement is the same. The rotation control of the development rotary 50 is easy.

  Further, as shown in FIGS. 5 and 6, various toner cartridges 55 having different depth dimensions from the surface of the development rotary 50 (different toner capacities) can be combined. In addition, since only the depth is different and the cross-sectional shape is the same, the space for attaching and detaching can be shared, and even a large capacity toner cartridge 55c, 55d does not require a large space for detaching.

  Further, since the toner cartridge 55 is provided with a lock mechanism 70 in the vicinity of the surface portion of the developing rotary 50, the operability of locking / unlocking is good, and even toner cartridges having different depths are common. A lock mechanism can be employed.

(Other examples)
Note that the image forming apparatus according to the present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the gist thereof.

  In particular, the detailed configuration of the developing rotary, the detailed configuration and shape of each developing device, and the toner cartridge are arbitrary.

1 is a schematic configuration diagram illustrating a color printer which is an embodiment of an image forming apparatus according to the present invention. FIG. 2 is a schematic configuration diagram when a toner cartridge is taken out from the color printer. The developing rotary mounted in the color printer is shown, (A) is a perspective view, and (B) is an exploded perspective view. It is a schematic sectional drawing of the said development rotary. FIG. 3 is a schematic cross-sectional view showing each toner cartridge to be combined. (A), (B), and (C) are cross-sectional views showing a state in which the toner cartridges are mounted in combination on the development rotary. FIGS. 4A and 4B are explanatory views showing a lock mechanism of the toner cartridge, wherein FIG. 5A shows a locked state, FIG. 5B shows an unlocked state, and FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Color printer 11 ... Photoconductor drum 50 ... Development rotary 51 ... Developing device 53 ... Housing 55 ... Toner cartridge 60 ... Support plate 61 ... Support shaft 70 ... Lock mechanism

Claims (6)

A plurality of developing means are held at a predetermined interval in the circumferential direction of the support shaft so that the developing cartridge can be intermittently rotated around the support shaft to the developing area, and a toner cartridge for replenishing toner for each developing means is attached and detached. In an image forming apparatus provided with a developing rotary attached freely,
The developing rotary includes support members that support the plurality of developing units at both ends in the axial direction, and at least one bottom portion of the toner cartridge is disposed in an axial center portion between the support members.
An image forming apparatus.   2. The image forming apparatus according to claim 1, wherein each of the plurality of developing units includes a housing, and support members for the developing rotary are fixed to both ends of the housing.   The image forming apparatus according to claim 1, wherein the plurality of developing units are arranged at equal intervals in a circumferential direction around a shaft portion of the developing rotary.   4. The image according to claim 1, wherein the control for rotating the developing rotary at the time of development is the same as the control for rotating the developing rotary when the toner cartridge is attached or detached. Forming equipment.   The image forming apparatus according to claim 1, wherein the toner cartridge has different depth dimensions from the surface of the developing rotary. The image forming apparatus according to claim 1, wherein the toner cartridge includes a lock mechanism at the time of mounting near the surface of the developing rotary.

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