JP2006171633A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tandem type color image forming apparatus achieving the simplification of the configuration of a driving force transmitting mechanism and the facilitation of the removal of a cartridge in/from an apparatus body, and obtaining a high-quality color image. <P>SOLUTION: In the tandem type color image forming apparatus forming the color image, the photoreceptor and the developing device in each image forming station are formed as an integrated cartridge, and constituted so that they receive driving force from one motor pinion respectively. The driven gear of the photoreceptor is left in the apparatus body, and is connected with the photoreceptor in the cartridge through a coupling, and then the driven gear of the developing device in the cartridge and the driven gear of the developing device in the apparatus body are meshed with each other. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  According to the present invention, an image forming station in which a charging unit, an image writing unit, and a developing unit are arranged around an image carrier is provided for each color along the transfer belt, and the transfer belt is passed through each image forming station. The present invention relates to a tandem color image forming apparatus for forming an image.

  Conventionally, in an image forming apparatus using an electrophotographic technique, a photosensitive member as an image carrier is charged by a charging unit, and a latent image is formed by irradiating light on the charged photosensitive member according to image information. The latent image is developed by developing means, and the developed toner image is transferred to a recording medium to form an image.

  When an image forming apparatus using electrophotography is used for a long time, it is necessary to replace the photosensitive drum, to supply and replace the developer, and to adjust, clean, and replace other parts (such as a charger and a cleaner container). However, such maintenance work is practically difficult except for a service person having specialized knowledge.

  Therefore, in the image forming apparatus using the electrophotographic image forming process, the electrophotographic photosensitive member and the process means acting on the electrophotographic photosensitive member are integrated into a cartridge, and the cartridge can be attached to and detached from the image forming apparatus main body. The process cartridge method is adopted. According to this process cartridge system, the user can perform maintenance of the apparatus by himself / herself without depending on the service person, so that the operability can be remarkably improved. Therefore, this process cartridge system is widely used in image forming apparatuses.

  Conventionally, there is a tandem type color image forming apparatus in which a plurality of photosensitive drums are arranged in a line. This is because yellow, magenta, cyan, and black are transferred by four photosensitive drums arranged along a transfer material conveyance path while carrying and conveying the transfer material by an electrostatic transfer belt stretched by a plurality of rollers. Are sequentially transferred onto a sheet, and a color image is formed by superimposing each color.

  This configuration has attracted attention in recent years because it can print at high speed. However, since each color is formed by four photosensitive drums, the photosensitive drum is more sensitive than a color image forming apparatus configured to superimpose colors for each color via four transport buses. Further accuracy is required for the rotational drive of the body drum. Also, in this type of apparatus, the image forming mechanism is unitized to form a process cartridge that can be detached from the main body of the image forming apparatus so that maintenance can be performed easily.

In such an image forming apparatus, it is necessary to detach the image carrier from the drive transmission mechanism in order to attach and detach the process cartridge. There is a fear. For this reason, the ease of attaching and detaching the cartridge to the apparatus main body and the certainty of the engaged state are required.
JP 2000-276030 A

  However, in the case of a conventional photosensitive member / developer-integrated cartridge, the driving source of the photosensitive member, which requires rotational accuracy, is separated from the driving unit of the developing unit and the cleaning unit, and the driving force is transmitted to each driven member. Since this is performed by the coupling means, the driving force transmission mechanism is complicated, and there is a problem that the engagement / disengagement of the driving transmission means at the time of cartridge detachment is complicated due to problems such as phase alignment.

  The present invention provides a tandem type color image forming apparatus that solves the above-described problems, simplifies the configuration of the driving force transmission mechanism, facilitates the detachment of the main body of the cartridge, and obtains a high-quality color image. With the goal.

  In order to solve the above problems, the first invention of the present invention is a tandem type color image forming apparatus for forming a color image, in which the photoconductor / developer of each image forming station is an integrated cartridge, and the photoconductor and the developing device. The device is configured to receive a driving force from one motor pinion, and the photosensitive member driven gear is left in the apparatus main body, and the photosensitive member driven gear and the photosensitive member in the cartridge are connected by coupling, The developing device driven gear meshes with the developing device driven gear in the apparatus main body.

  The second invention is characterized in that, in the tandem color image forming apparatus of the first invention, the photosensitive member driven gear and the developer driven gear are arranged linearly across the motor pinion.

  According to a third aspect of the present invention, in the tandem type color image forming apparatus according to the first or second aspect of the present invention, the developer driven gear in the apparatus main body is slidable in the axial direction.

  According to a fourth aspect of the present invention, in the tandem color image forming apparatus according to any one of the first to third aspects of the invention, the photoconductor is cleanerless.

In a tandem type color image forming apparatus for forming a color image, the photoconductor / developer of each image forming station is an integrated cartridge, and the photoconductor and the developer are each configured to receive a driving force from one motor pinion. In addition, the photosensitive member driven gear is left in the apparatus main body, the photosensitive member driven gear and the photosensitive member in the cartridge are connected by coupling, and the developing device driven gear in the cartridge and the developing device driven in the apparatus main body are connected. The drive gear receiving portion can be centrally arranged by engaging the gear, and the developer drive is handed over just by adjusting the phase of the coupling of the photoconductor drive. Desorption is facilitated.
With the configuration in which the photosensitive member driven gear and the developer driven gear are arranged linearly across the motor pinion, the influence of the load variation from the non-developer driving gear with large load variation on the photosensitive member driven gear can be reduced. It can be reduced, and the motor pinion can be prevented from falling down.
With the configuration in which the developing device driven gear in the apparatus main body is slidable in the axial direction, the cartridge can be easily attached and detached.
With the configuration in which the photoconductor is cleanerless, the cartridge can be reduced in size.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an overall configuration of a color image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing a partial configuration of one embodiment of the color image forming apparatus of the present invention. In the following description, the same numbers may be assigned between the drawings, and the description may be omitted. In this embodiment, an intermediate transfer belt is used as the transfer belt.

  1 and 2, the image forming apparatus 1 of the present embodiment includes a housing body 2, and an image forming unit 6, a transfer belt unit 9, and a paper feeding unit 10 are disposed in the housing body 2. A secondary transfer unit 11, a fixing unit 12, and a recording medium conveying unit 13 are disposed. The consumables in the image forming unit 6 and the paper feeding unit 10 are configured to be detachable from the main body. In this case, the configuration including the transfer belt unit 9 can be removed and repaired or replaced. It has become.

  The transfer belt unit 9 includes a driving roller 14, a driven roller 15 disposed obliquely above the driving roller 14, and an intermediate belt that is stretched between the two rollers 14 and 15 and circulated in the direction of the arrow shown in the figure. A transfer belt 16 and a cleaning means 17 that contacts the surface of the intermediate transfer belt 16 are provided, and the driven roller 15 and the intermediate transfer belt 16 are disposed in a direction inclined to the left in the drawing with respect to the drive roller 14. Yes. As a result, the belt surface 16a with the belt conveyance direction downward when the intermediate transfer belt 16 is driven is positioned below. In the present embodiment, the belt surface 16a is a belt tension surface (surface pulled by the drive roller 14) when the belt is driven.

  The primary transfer member 21 is elastically applied to the back surface 16a of the intermediate transfer belt 16 facing the image carrier 20 of each image forming station Y, M, C, K, which will be described later. The primary transfer member 21 in contact may be in the form of a leaf spring or a roller as shown in the figure. A transfer bias is applied to the primary transfer member 21.

  A test pattern sensor 18 is installed on the support frame 9 a of the transfer belt unit 9 in the vicinity of the drive roller 14. This test pattern sensor 18 is a sensor for positioning each color toner image on the intermediate transfer belt 16, detecting the density of each color toner image, and correcting the color shift and image density of each color image.

  The image forming unit 6 includes image forming stations Y (for yellow), M (for magenta), C (for cyan), and K (for black) that form a plurality (four in this embodiment) of different color images. Each of the image forming stations Y, M, C, and K includes an image carrier 20 formed of a photosensitive drum, and a charging unit 22, an image writing unit 23, and a developer disposed around the image carrier 20. Means 24 are provided. In the developing unit 24, only the image forming station K is assigned a drawing number, and the other image forming stations have the same configuration, and thus the drawing number is omitted. Further, the arrangement order of the image forming stations Y, M, C, and K is arbitrary.

  Then, the image carrier 20 of each of the image forming stations Y, M, C, and K is brought into contact with the belt surface 16a facing downward in the transport direction of the intermediate transfer belt 16, and as a result, each of the image forming stations Y, M. , C and K are also arranged in a direction inclined to the left in the drawing with respect to the drive roller 14. The image carrier 20 is rotationally driven in the conveyance direction of the intermediate transfer belt 16 as indicated by the arrows in the figure.

  In the present embodiment, the image stations Y, M, C, and K are disposed in an oblique direction, and the image carrier 20 is in contact with the belt surface 16a facing downward in the conveyance direction of the intermediate transfer belt 16, The toner storage container 26 is disposed obliquely downward.

  The developing unit 24 includes a toner storage container 26 that stores toner (hatched portion in the drawing), a toner storage part 27 formed in the toner storage container 26, and a toner stirring member disposed in the toner storage part 27. 29, a partition member 30 partitioned at the upper portion of the toner storage portion 27, a toner supply roller 31 disposed above the partition member 30, and abutment against the toner supply roller 31 provided on the partition member 30. The blade 32, the developing roller 33 disposed so as to be in contact with the toner supply roller 31 and the image carrier 20, and the regulation blade 34 that is in contact with the developing roller 33. The toner is a negatively charged toner made of a one-component nonmagnetic toner. The toner supply roller 31 and the developing roller 33 rotate in the same direction.

  The image carrier 20 is rotated in the conveying direction of the intermediate transfer belt 16, and the developing roller 33 and the supply roller 31 are rotationally driven in a direction opposite to the rotation direction of the image carrier 20, as shown by the arrows in the figure. The stirring member 29 is driven to rotate in the direction opposite to the direction of rotation of the supply roller 31. The toner stirred and carried up by the stirring member 29 in the toner storage unit 27 is supplied to the toner supply roller 31 along the upper surface of the partition member 30, and the supplied toner is rubbed against the blade 32 and slid on the supply roller 31. The toner is supplied to the surface of the developing roller 33 by a mechanical adhesion force to the surface uneven portion and an adhesion force by frictional band power. The toner supplied to the developing roller 33 is regulated to a predetermined thickness by the regulating blade 34, and the thinned toner layer is conveyed to the image carrier 20 so that the developing roller 33 and the image carrier 20 come into contact with each other. The latent image portion of the image carrier 20 is developed at the nip portion configured as described above and in the vicinity thereof.

  The paper feed unit 10 includes a paper feed unit including a paper feed cassette 35 in which the recording media P are stacked and held, and a pickup roller 36 that feeds the recording media P from the paper feed cassette 35 one by one. In the first opening / closing member 3, a registration roller pair 37 that defines the feeding timing of the recording medium P to the secondary transfer unit, and a secondary transfer unit that is pressed against the drive roller 14 and the intermediate transfer belt 16. A secondary transfer unit 11, a fixing unit 12, a recording medium conveyance unit 13, a paper discharge roller pair 39, and a duplex printing conveyance path 40 are provided.

  The secondary transfer unit 11 includes a rotation lever 42 pivotally supported by a fixed shaft 41, a secondary transfer roller 19 rotatably provided at one end of the rotation lever 42, and a rotation lever 42. The secondary transfer roller 19 is normally moved in the direction of the arrow by the bias of the spring 43 to drive the intermediate transfer belt 16 and the drive. The roller 14 can be pressed. An eccentric cam 44 is provided on the spring 43 side of the rotation lever 42, and the rotation lever 42, the spring 43, and the eccentric cam 44 constitute a means for separating and contacting the secondary transfer roller 19. Then, the rotation of the eccentric cam 44 causes the rotation lever 42 to rotate against the spring 43 so that the secondary transfer roller 19 is separated from the intermediate transfer belt 16.

  The fixing unit 12 includes a heating roller 45 that includes a heating element such as a halogen heater and is rotatable, a pressure roller 46 that presses and biases the heating roller 45, and is swingable on the pressure roller 46. The belt tension member 47, and the heat-resistant belt 49 stretched between the pressure roller 45 and the belt tension member 47, and the color image secondarily transferred to the recording medium are the heat roller 45 and the heat-resistant belt 49. The toner image is fixed on the recording medium at a predetermined temperature at the nip portion formed in step (b). In the present embodiment, the fixing unit 12 can be disposed in a space formed obliquely above the intermediate transfer belt 16, in other words, in a space opposite to the image forming unit 6 with respect to the intermediate transfer belt 16. Thus, heat transfer to the electrical component box, the image forming unit 6 and the intermediate transfer belt 16 can be reduced, and the frequency of performing the color misregistration correction operation for each color can be reduced.

  FIG. 3 is a plan view showing a wheel train arrangement of the drive transmission mechanism of the image forming unit 6 and the transfer belt unit 9. First to fourth drive motors are individually arranged in the image forming stations Y, M, C, and K of the image forming unit 8. Motor pinions 50Y, 50M, 50C, and 50K of the respective drive motors mesh with the photosensitive member drive idle gears 51Y to 51K and the developer drive idle gears 52Y to 52K.

  The train wheel arrangement of the image forming stations Y, M, C, and K is such that the photoconductor drive idle gears 51Y, 51M, 50C, and 50K and the development drive first are sandwiched between the motor pinions 50Y, 50M, 50C, and 50K. The idle gears 52Y, 52M, 52C, and 52K are arranged on a straight line. By making the train wheel arrangement linear, it is possible to reduce the influence on the photosensitive member driven gear where the rotation accuracy of the load fluctuation of the developing device driven gear having a large load fluctuation due to the toner amount fluctuation is required, and The motor pinion can be prevented from falling down.

  Each development drive first idle gear 52Y, 52M, 52C, 52K meshes with each development drive second idle gear 53Y, 53M, 53C, 53K. In the image forming stations Y, M, C, and K, the photosensitive member drive first idle gears 51Y, 51M, 51C, and 51K and the development drive first idle gears 52Y, 52M, and 52C from the motor pinions 50Y, 50M, 50C, and 50K. , Branch into two branches at 52K.

  FIG. 4 is a cross-sectional view of the drive transmission mechanism of the image forming stations Y, M, C, and K that are bifurcated. In the image forming apparatus according to the present invention, in each image forming station, a photosensitive drum / developer-integrated cartridge system is used, and a portion surrounded by an alternate long and short dash line indicates a cartridge. By making the photoreceptor 20 cleanerless, the cartridge can be reduced in size. A drive motor 57 is attached to the lower surface of the drive board 56 of the apparatus main body. A first wheel train support plate 58 is attached to the upper surface of the drive board 56, and a second wheel train support plate 59 is attached on the first wheel train support plate 58. Motor pinions 50 </ b> Y, M, C, and K of the drive motor 57 protrude on the upper surface of the drive substrate 56. Photosensitive member driving idle gears 51Y, 51M, 51C, 51K are rotatably arranged above and below a shaft 60 supported at both ends by the driving substrate 56 and the first train wheel support plate 57. Development drive first idle gears 52Y, 52M, 52C, 52C are arranged on a shaft 61 supported at both ends by a drive board 55 and a second train wheel support plate 58, and can be moved up and down via a spring 61 so as to be rotatable. .

  The development drive first idle gears 52Y, M, C, and K of the apparatus main body mesh with the development drive second idle gears 53Y, 53M, C, and K in the cartridge. The development drive second idle gears 53 </ b> Y, M, C, and K mesh with the development drive gear 67 to drive the development roller 33.

  The motor pinions 50Y, M, C, and K mesh with the photoreceptor driving idle gears 51Y, 51M, 51C, and 51K. The motor pinions 50Y, M, C, and K mesh with the development drive first idle gears 52Y, M, and C of different axes. A photosensitive gear 63 is rotatably arranged on a photosensitive gear shaft 62 supported at one end by the drive substrate 55. The photoconductor gear 63 meshes with the photoconductor drive idle gear 51Y, M, C, K. The photoconductor gear shaft 62 extends to a height protruding from the upper surface of the first train wheel support plate 58, and a coupling portion 64 is integrated with the upper end of the photoconductor gear 63 that is rotatably arranged on the photoconductor gear shaft 62. Formed. The coupling portion 64 engages with a coupling portion formed at the end portion of the photoreceptor 20 in the cartridge, and transmits a driving force.

  The driving force is transmitted from the apparatus main body of the photosensitive member 20 and the developing roller 33 in the cartridge, one is coupled and the other is geared, so that the apparatus can be miniaturized and the cartridge can be easily attached and detached. It becomes.

It is a figure which shows embodiment of this invention. It is a figure which shows embodiment of this invention. It is a figure which shows embodiment of this invention. It is a figure which shows embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1: Image forming apparatus 2: Housing main body 9: Transfer belt unit 10: Paper feed unit 11: Secondary transfer unit 12: Fixing unit 13: Recording medium conveyance means 14: Transfer belt drive roller 15: Driven roller 16: Intermediate transfer belt 17: Cleaning means 18: Test pattern sensor 19: Secondary transfer roller 20: Image carrier 21: Primary transfer member 22: Charging means 23: Image writing means 24: Developing means 26: Toner storage container 27: Toner storage section 29: Toner stirring member 30: Partition member 31: Toner supply roller 32: Blade 33: Development roller 34: Restriction blade 35: Paper feed set 36: Pickup roller 37: Registration roller pair 39: Paper discharge roller pair 40: For duplex printing Conveyance path 41: Fixed shaft 42: Rotating lever 43: Spring 44: Eccentricity Cam 45: Heating roller 46: Pressure roller 47: Belt stretch member 49: Heat-resistant belt 50Y, 50M, 50C, 50K: First to fourth drive motor pinions 51Y, 51M, 51C, 51K: Photoconductor drive idle gear 52Y , 52M, 52C, 52K: Development drive first idle gear 53Y, 53M, 53C, 53K: Development drive second idle gear 56: Drive substrate 57: Motor 58: First train wheel support plate 59: Second train wheel support plate 60: shaft 61: shaft 62: photoconductor gear shaft 63: photoconductor gear 64: coupling portion 65: shaft 67: development drive gear

Claims (4)

In a tandem type color image forming apparatus for forming a color image, the photoconductor / developer of each image forming station is an integrated cartridge, and the photoconductor and the developer are each configured to receive a driving force from one motor pinion. In addition, the photosensitive member driven gear is left in the apparatus main body, the photosensitive member driven gear and the photosensitive member in the cartridge are connected by coupling, and the developing device driven gear in the cartridge and the developing device driven in the apparatus main body are connected. A tandem type color image forming apparatus, which meshes with a gear. 2. The tandem type color image forming apparatus according to claim 1, wherein the photosensitive member driven gear and the developer driven gear are arranged linearly with the motor pinion interposed therebetween. The tandem type color image forming apparatus according to claim 1, wherein a developer driven gear in the apparatus main body is slidable in an axial direction. The tandem color image forming apparatus according to claim 1, wherein the photoconductor is cleanerless.

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