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CN-115668069-B - Image forming apparatus having a plurality of image forming units

CN115668069BCN 115668069 BCN115668069 BCN 115668069BCN-115668069-B

Abstract

The invention provides an image forming apparatus, which can position a fixing unit with high precision by a small number of parts and ensure good assembling and disassembling performance of the fixing unit. A driven gear (84) is connected to the rear end of one of a rotary fixing member (81) and a rotary pressing member (82) of a fixing unit (8) in the unit insertion/removal direction, and the driven gear (84) is meshed with a drive gear (14) provided in the image forming apparatus main body. A transmission force (F) transmitted from the tooth surface of the driving gear (14) to the tooth surface of the driven gear (84) at the meshing position of the driving gear (14) and the driven gear (84) has a component for pressing the fixing unit (8) in the horizontal direction toward the pair of struts (121, 122). The fixing unit (8) is pressed by the pair of support posts (121, 122) by the driving force in a state of being accommodated in the fixing unit accommodating part (2 e), and is positioned in a direction perpendicular to the inserting and extracting direction.

Inventors

  • Assistant rattan is strong large

Assignees

  • 京瓷办公信息系统株式会社

Dates

Publication Date
20260508
Application Date
20210513
Priority Date
20200520

Claims (7)

  1. 1. An image forming apparatus including an image forming apparatus main body including a fixing unit configured to fix a toner image on a sheet by passing the sheet to which the toner image is to be carried through a nip portion formed by pressing the sheet against each other by a rotary fixing member and a rotary pressing member, and a fixing unit housing portion configured to removably house the fixing unit, The inserting and pulling direction of the fixing unit relative to the fixing unit accommodating part is consistent with the axial direction of the rotary pressurizing member, The framework of the image forming device comprises a pair of struts arranged adjacent to the fixing unit accommodating part and arranged at intervals in the inserting and extracting direction of the fixing unit, the struts are abutted against the side surface of the fixing outer cover of the fixing unit to position the fixing outer cover, a pair of cross beams are respectively connected with the struts at right angles in the inserting and extracting direction to support the lower surface of the fixing unit, The image forming apparatus further includes: a driven gear integrally connected to a rotation fixing member or a rotation pressing member of the fixing unit and rotated at a rear end in the insertion/extraction direction; a driving gear provided at a rear end portion of the fixing unit housing portion in the insertion/extraction direction and engaged with the driven gear when the fixing unit is housed in the fixing unit housing portion, and A driving source for driving the driving gear to rotate, The drive gear and the driven gear, when transmitting power, have a transmission force transmitted from the tooth surface of the drive gear to the tooth surface of the driven gear at the meshing position of each other, have a component of pressing the fixing unit toward the pair of struts in the horizontal direction, The fixing unit is pushed by the pair of support posts by the driving force and is positioned in a direction perpendicular to the insertion/removal direction in a state of being accommodated in the fixing unit accommodating section.
  2. 2. The image forming apparatus according to claim 1, wherein the drive gear and the driven gear pass through a vertical plane including a surface of the fixing unit housing portion side of the pair of stay and an upper side of a crossing position of a horizontal plane including an upper surface of the pair of cross members, as viewed from a direction of insertion and extraction of the fixing unit, when transmitting power.
  3. 3. The image forming apparatus according to claim 1, wherein the drive gear and the driven gear pass through a position where an extension line of the driving force crosses a vertical plane including a surface of the fixing unit housing portion side of the pair of stay and a horizontal plane including an upper surface of the pair of cross members, as viewed from a direction of insertion and extraction of the fixing unit, when the driving gear and the driven gear transmit the driving force.
  4. 4. The image forming apparatus according to claim 1, wherein a component force in a horizontal direction of the driving force is equal to a component force in a vertical direction when the driving gear and the driven gear transmit power.
  5. 5. The image forming apparatus according to claim 1, wherein the driving gear and the driven gear transmit power such that a component force in a horizontal direction of the driving force is larger than a component force in a vertical direction when transmitting power.
  6. 6. The image forming apparatus according to any one of claims 1 to 5, wherein, The fixing unit housing portion side surfaces of the pair of support posts have two ridge lines extending in the up-down direction and arranged at intervals in the insertion/extraction direction of the fixing unit, The fixing unit is brought into contact with the two ridge lines provided on each of the pair of struts when pressed against the pair of struts by the driving force.
  7. 7. The image forming apparatus according to claim 6, wherein, On the surface of the fixing unit pressed against the pair of support posts, an abutment seat portion is provided so as to protrude and abut against the pair of support posts, Each of the abutment portions is capable of abutting against the two ridge lines formed on the respective one of the pair of support posts when the fixing unit is pressed against the support posts.

Description

Image forming apparatus having a plurality of image forming units Technical Field The present invention relates to an image forming apparatus. Background In general, an electrophotographic image forming apparatus includes a fixing unit that fixes a toner image on a sheet by a fixing roller and a pressure roller that rotate in a state of being in pressure contact with each other. In the fixing unit, when a sheet passes through a nip portion formed between a fixing roller and a pressing roller, a toner image on the sheet is heated and pressed and fixed on the sheet. The fixing unit generally has a housing accommodating a fixing roller and a pressing roller. The housing is detachably attached to the image forming apparatus main body. Patent document 1 discloses an example of a structure for attaching and detaching a fixing unit to and from an image forming apparatus main body. In the image forming apparatus, the attaching/detaching direction of the fixing unit is set to be perpendicular to the longitudinal direction of the housing (the axial direction of the fixing roller). The two sides of the shell along the long side direction are respectively provided with a clamping pin in a protruding way. The image forming apparatus main body is provided with a pressing member that engages with each engagement pin when the fixing unit is attached to the image forming apparatus main body, and presses the fixing unit toward an attaching direction to the image forming apparatus main body by a biasing force of the biasing member. The pressing member is rotatably disposed about a predetermined axis, and the engagement between the pressing member and the engagement pin is released by operating the operation handle. Prior art literature Patent document 1 Japanese patent laid-open publication No. 2013-072987 As shown in patent document 1, in a conventional positioning structure in which an engagement pin provided in a fixing unit is engaged with an engagement groove provided in an image forming apparatus main body, in order to secure the attachment/detachment property of the fixing unit, it is necessary to increase the diameter of the engagement groove with respect to the engagement pin. However, if the diameter of the engagement groove with respect to the engagement pin is increased, there is a problem in that the positioning accuracy of the fixing unit is lowered. In addition, in the conventional positioning structure, a force mechanism (force member or the like) for fixing the fixing unit to the image forming apparatus main body and a release mechanism (operation handle or the like) for releasing the fixing are required to be separately provided. Therefore, there is a problem that the number of parts increases, which results in an increase in cost. Disclosure of Invention In view of the above, an object of the present invention is to position a fixing unit with high accuracy with a small number of parts and to ensure good attachment/detachment of the fixing unit. An image forming apparatus includes an image forming apparatus main body including a fixing unit configured to fix a toner image on a sheet by passing the sheet to which the toner image is carried through a nip portion formed by pressing the sheet against each other by a rotary fixing member and a rotary pressing member, and a fixing unit housing portion configured to house the fixing unit in a removable manner. The fixing unit is configured to be inserted into and removed from the fixing unit housing portion in a direction consistent with an axial direction of the rotary pressing member, and the frame of the image forming apparatus includes a pair of support posts disposed adjacent to the fixing unit housing portion and arranged at intervals in the insertion and removal direction of the fixing unit; the image forming apparatus further includes a driven gear rotatably connected to one of a rotary fixing member and a rotary pressing member of the fixing unit and having a rear end in the insertion direction, a drive gear provided at the rear end in the insertion direction of the fixing unit housing portion and engaged with the driven gear when the fixing unit is housed in the fixing unit housing portion, and a drive source for driving the rotation of the drive gear, wherein a transmission force transmitted from a tooth surface of the drive gear to a tooth surface of the driven gear when power is transmitted is provided at an engagement position between the drive gear and the driven gear, the drive gear having a component for pressing the fixing unit in a horizontal direction toward the pair of the struts, and the fixing unit being positioned in a direction perpendicular to the insertion direction by the transmission force while being housed in the fixing unit housing portion. According to the present invention, the fixing unit can be positioned with high accuracy with a small number of parts and good removability of the fixing unit is ensured. Drawings Fig. 1 is a sch