JP2015086047A - Image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation device capable of smooth turnaround of paper.SOLUTION: A printer capable of both-sided printing is provided with a side guide 34 which, in an inversion pass in which paper P that has passed a fixing unit is transported between a photosensitive drum and a transfer unit, regulates moving to left side of the paper P being transported while guiding the paper P being transported downward so that it makes turnaround to the front. The side guide 34 includes a lower wall 54 which bends frontward as advances downward, an upper wall 55 which is arranged to face the lower wall 54 with an interval inside the bending of the lower wall 54, and a side wall 56 continuous to a left end part of the lower wall 54 and the left end part of the upper wall 55. The upper end part of the upper wall 55 is positioned upper than the upper end part of the lower wall 54.

Description

  The present invention relates to an image forming apparatus employing an electrophotographic system.

  An image forming apparatus capable of duplex printing is known as an electrophotographic image forming apparatus.

  For example, the conveyance path for forming an image on one side of the paper in the paper feed tray and the paper on which the image is formed on one side are reversed after passing through the fixing device to form an image on the other side. An image forming apparatus provided with a conveyance path for this purpose has been proposed (see, for example, Patent Document 1).

JP 2009-179411 A

  In the above-described image forming apparatus described in Patent Document 1, the feed path for forming an image on the paper that has passed through the fixing unit includes a skew feeding guide that guides the widthwise end of the paper at a portion where the paper is redirected. Is provided.

  However, the paper that has passed through the fixing unit may be curled when passing through the fixing unit. In that case, it may be difficult to smoothly change the direction of the sheet, for example, when the sheet contacts the upper edge of the skew feeding guide.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that can smoothly change the direction of a sheet.

(1) In order to achieve the above object, the image forming apparatus of the present invention includes a first guide member, a second guide member, and a third guide member. The first guide member is configured to guide a recording medium conveyed in a predetermined first direction. The second guide member is disposed downstream of the first guide member in the first direction, and guides the recording medium transported in the first direction to change the direction in a second direction different from the first direction. However, it is configured to regulate the position in the width direction of the recording medium to be conveyed. The third guide member is disposed downstream of the second guide member in the second direction, and is configured to guide a recording medium conveyed in the second direction.

  The second guide member is disposed so as to face the first wall at a distance inwardly from the first wall curved in the second direction as it goes downstream in the first direction. A wall, and a third wall continuous to one end in the width direction of the first wall and one end in the width direction of the second wall.

  The upstream end portion in the first direction of the second wall is located upstream of the upstream end portion in the first direction of the first wall in the first direction.

  According to such a configuration, the recording medium conveyed toward the downstream in the first direction is placed between the first wall and the second wall while being along the upstream end of the second wall in the first direction. Can be introduced.

  Therefore, when the recording medium is introduced between the first wall and the second wall, the recording medium contacts the upstream edge in the first direction of the first wall and the upstream edge in the first direction of the second wall. This can be suppressed.

As a result, the recording medium can be reliably introduced between the first wall and the second wall, and the direction can be smoothly changed.
(2) The downstream end portion in the first direction of the first guide member is disposed upstream in the first direction with respect to the first wall, and is spaced in the second direction with respect to the upstream end portion in the first direction of the second wall. You may face each other.

According to such a configuration, the recording medium is passed between the downstream end portion in the first direction of the first guide member and the upstream end portion in the first direction of the second wall, and the first wall and the second wall. It can be reliably introduced between the walls.
(3) The downstream end of the first guide member in the first direction may have a curved portion that curves in the second direction as it goes downstream in the first direction. In this case, the bending portion overlaps the upstream end portion of the first wall in the first direction when viewed from the first direction.

  According to such a configuration, the recording medium is guided in the second direction as it goes downstream in the first direction by the curved portion overlapping the upstream end portion in the first direction of the first wall when viewed from the first direction. Can do.

  Therefore, the recording medium can be introduced between the first wall and the second wall while being guided in the second direction rather than the first wall.

As a result, it is possible to suppress the recording medium guided by the first guide member from coming into contact with the upstream edge of the first wall in the first direction.
(4) The upstream edge in the first direction of the third wall may be continuous with the upstream edge in the first direction of the first wall and the upstream edge in the first direction of the second wall.

According to such a configuration, when the recording medium is introduced between the first wall and the second wall, the third wall can restrict the recording medium from being shifted to one side in the width direction.
(5) The upstream end edge of the third wall in the first direction is continuous with the upstream end edge of the first wall in the first direction and extends in a direction orthogonal to the first direction, and the second wall In a direction that is continuous with the upstream edge in the first direction and that extends in a direction perpendicular to the first direction, is continuous with the first edge and the second edge, and is inclined with respect to the first direction. A third end edge may be provided.

  According to such a configuration, since the upstream end edge in the first direction of the third wall is bent, it has higher rigidity than the case where it is not bent.

Therefore, when the recording medium is introduced between the first wall and the second wall, the third wall can more reliably restrict the recording medium from being shifted to one side in the width direction.
(6) The third wall extends in the second direction from the first restriction portion that extends along the first direction and the position that overlaps with the second edge when viewed in the first direction. Accordingly, a second restricting portion that extends obliquely toward the other in the width direction may be included.

According to such a configuration, the first restricting portion restricts the recording medium conveyed in the first direction from shifting to one side in the width direction, and the second restricting portion conveys the recording medium conveyed in the second direction. Can be moved to the other side in the width direction.
(7) The second wall extends linearly so as to incline in the second direction as it goes to the first direction, continuously with the first portion extending linearly along the first direction. You may provide the 2nd part and the 3rd part extended while curving in the 2nd direction following the 2nd part.

  According to such a configuration, since the second portion extends linearly, the curved first wall and the linear second portion are compared with the case where the second portion is curved. A wide interval can be set.

As a result, the direction of the recording medium can be smoothly changed.
(8) The second guide member may include a positioning portion for determining the position of the second guide member with respect to the third guide member.

  According to such a configuration, the second guide member can be positioned with respect to the third guide member without providing a separate member.

  Therefore, the second guide member can be accurately arranged with respect to the third guide member.

As a result, the recording medium can be smoothly transferred from the second guide member to the third guide member.
(9) An image forming apparatus of the present invention is configured to transfer an image bearing member configured to carry a developer image to the recording medium so as to face the image bearing member and to carry the developer image carried on the image bearing member. The image forming apparatus includes: a transfer device configured to: a fixing device configured to heat the recording medium on which the developer image has been transferred to fix the developer image on the recording medium; and the recording medium that has passed through the fixing device. A conveyance mechanism configured to convey between the body and the transfer device may be further included. In this case, the second guide member may be configured to guide the first direction change of the recording medium conveyed in the first direction by the conveyance mechanism in the second direction.

  According to such a configuration, the recording medium that has passed through the fixing device can be reliably introduced between the first wall and the second wall, and can be smoothly turned.

  According to the image forming apparatus of the present invention, it is possible to reliably introduce the recording medium between the first wall and the second wall and smoothly change the direction.

FIG. 1 is a central sectional view showing a printer as a first embodiment of an image forming apparatus of the present invention. FIG. 2 is a perspective view of the lower frame shown in FIG. FIG. 3 is an enlarged view of a main part of FIG. FIG. 4 is a right side view of the side guide shown in FIG. 5A is a perspective view of the side guide shown in FIG. 4 as viewed from the left front side. 5B is a perspective view of the side guide shown in FIG. 4 as viewed from the lower right. FIG. 6 is a plan view of the side guide shown in FIG.

1. Overall Configuration of Printer As shown in FIG. 1, a printer 1 as an example of an image forming apparatus is a horizontal type direct tandem color laser printer.

  In the following description, when referring to the direction, the state in which the printer 1 is placed horizontally is used as the upper and lower reference. That is, the upper side of the drawing in FIG. 1 is the upper side, and the lower side of the drawing in FIG. 1 is the lower side. Further, the left side of FIG. 1 is the front, and the right side of FIG. 1 is the rear. In addition, when the printer 1 is viewed from the front, the left and right reference is used. That is, the front side of the page of FIG. 1 is the right side, and the back side of the page is the left side. The direction from the top to the bottom is an example of the first direction. The direction from the rear to the front is an example of the second direction. The left-right direction is an example of the width direction.

  The printer 1 includes a main body casing 2, a process unit 3, a scanner unit 4, a transfer unit 5 as an example of a transfer device, and a fixing unit 6 as an example of a fixing device.

  The main casing 2 has a substantially box shape. The main casing 2 includes an opening 21, a front cover 22, a paper feed tray 7, and a paper discharge tray 8.

  The opening 21 is disposed at the front end of the main casing 2. The opening 21 communicates the inside and outside of the main casing 2 in the front-rear direction so as to allow passage of the process unit 3.

  The front cover 22 is disposed at the front end of the main casing 2. The front cover 22 has a substantially flat plate shape. The front cover 22 extends in the vertical direction, and is supported on the front wall of the main casing 2 with the lower end portion as a fulcrum. The front cover 22 opens and closes the opening 21.

  The paper feed tray 7 is disposed at the bottom of the main casing 2. The paper feed tray 7 is configured to accommodate paper P as an example of a recording medium.

  The paper discharge tray 8 is disposed on the upper wall of the main body casing 2. The paper discharge tray 8 is recessed downward from the upper surface of the main casing 2 so that the paper P is placed thereon.

  The process unit 3 is disposed in the center of the main casing 2. The process unit 3 includes a drum unit 9 and a plurality of developing cartridges 10.

  The drum unit 9 includes a photosensitive drum 11 as an example of a plurality of image carriers and a plurality of scorotron chargers 12.

  Each of the plurality of photosensitive drums 11 is rotatably supported at the lower end portion of the process unit 3. Each of the plurality of photosensitive drums 11 is arranged in parallel at an interval in the front-rear direction. Each of the plurality of photosensitive drums 11 has a substantially cylindrical shape extending in the left-right direction.

  Each of the plurality of scorotron chargers 12 corresponds to each of the plurality of photosensitive drums 11, and is disposed above and behind the corresponding photosensitive drum 11 at an interval.

  Each of the plurality of developing cartridges 10 corresponds to each of the plurality of photosensitive drums 11 and is disposed above the corresponding photosensitive drum 11. Each of the plurality of developing cartridges 10 includes a developing roller 13 and a supply roller 14. The developing cartridge 10 contains toner as an example of a developer corresponding to each color in a space above the developing roller 13 and the supply roller 14.

  The developing roller 13 is rotatably supported at the lower end portion of the developing cartridge 10 so as to be exposed rearward. Further, the developing roller 13 is in contact with the front upper end portion of the photosensitive drum 11.

  The supply roller 14 is disposed on the front upper side of the developing roller 13. The supply roller 14 is in contact with the front upper end portion of the developing roller 13.

  The scanner unit 4 is disposed above the process unit 3. As shown by a solid line in FIG. 1, the scanner unit 4 emits a laser beam toward the photosensitive drum 11 based on the image data to expose the photosensitive drum 11.

  The transfer unit 5 is disposed below the process unit 3. The transfer unit 5 includes a driving roller 15, a driven roller 16, a conveyance belt 17, and a plurality of transfer rollers 18.

  The drive roller 15 is disposed at the rear end portion of the transfer unit 5.

  The driven roller 16 is disposed at the front end portion of the transfer unit 5 so as to be opposed to the front side of the driving roller 15 with a space therebetween.

  The conveyor belt 17 is wound around the driving roller 15 and the driven roller 16 so that the upper portion thereof is in contact with all the photosensitive drums 11. The conveyor belt 17 moves in a circular motion such that the upper portion thereof moves from the front to the rear by the driving of the driving roller 15 and the driven of the driven roller 16.

  Each of the plurality of transfer rollers 18 corresponds to each of the plurality of photosensitive drums 11, and is disposed below the corresponding photosensitive drum 11 with the upper portion of the conveyance belt 17 interposed therebetween.

  The fixing unit 6 is disposed behind the transfer unit 5 and includes a heating roller 19 and a pressure roller 20 that contacts the heating roller 19.

  When the printer 1 starts an image forming operation, the scorotron charger 12 uniformly charges the surface of the photosensitive drum 11. Thereafter, the scanner unit 4 exposes the surface of the photosensitive drum 11. Thereby, an electrostatic latent image based on the image data is formed on the surface of the photosensitive drum 11.

  The supply roller 14 supplies the toner in the developing cartridge 10 to the developing roller 13. At this time, the toner is frictionally charged positively between the developing roller 13 and the supply roller 14 and is carried on the developing roller 13.

  The developing roller 13 supplies the carried toner to the electrostatic latent image on the surface of the photosensitive drum 11. As a result, a toner image as an example of a developer image is carried on the surface of the photosensitive drum 11.

  The paper P is transported forward and upward from the paper feed tray 7 by the rotation of various rollers, and then U-turns rearward and upward. The paper P is moved one by one between the yellow photosensitive drum 11 and the transport belt 17 at a predetermined timing. Paper is fed in between. Thereafter, the paper P is transported from the front to the rear by the transport belt 17. The toner image on the photosensitive drum 11 is transferred to the paper P when the paper P passes between the photosensitive drum 11 and the transfer roller 18.

  Thereafter, the sheet P is heated and pressed when it passes between the heating roller 19 and the pressure roller 20. At this time, the toner image on the paper P is thermally fixed to the paper P. Thereafter, the paper P is discharged to the paper discharge tray 8.

A path through which the paper P is transported forward and upward from the paper feed tray 7, transported from the front to the rear by the transport belt 17, and passes between the heating roller 19 and the pressure roller 20 is the first path. It is a transport route.
2. Reverse Path (1) Outline of Reverse Path As will be described in detail later, as indicated by a phantom line in FIG. 1, the printer 1 again transfers the paper P that has passed between the heating roller 19 and the pressure roller 20. A reversing path is provided as a second transport path for feeding between the yellow photosensitive drum 11 and the transport belt 17.

The reverse path extends in the vertical direction behind the fixing unit 6, is curved forward at the lower end portion thereof, extends in the front-rear direction below the paper feed tray 7, and is curved upward at the front end portion thereof. It joins the transport route.
(2) Configuration of Reversal Path The main casing 2 includes a low-voltage power supply unit 31, a rear cover 32 as an example of a first guide member, a pair of transport rollers 35, and a lower frame 33 as an example of a third guide member. And a side guide 34 as an example of a second guide member.

  The low voltage power supply unit 31 is disposed below the fixing unit 6 and above the rear end portion of the paper feed tray 7. The low voltage power supply unit 31 includes a low voltage power supply board 36 and a cover 37.

  The low-voltage power supply board 36 has a substantially flat plate shape extending in the front-rear direction. The low-voltage power supply board 36 converts an alternating current input from an external power supply into a direct current. The electric power converted into a direct current by the low-voltage power supply board 36 is converted into a predetermined voltage by a high-voltage power supply board (not shown) and supplied to each part of the printer 1.

  The cover 37 has a substantially box shape. The cover 37 is made of a metal material such as stainless steel and covers the low-voltage power supply substrate 36.

  The rear cover 32 is disposed behind the fixing unit 6 and the low-voltage power supply unit 31 at a rear end portion of the main body casing 2 with a space therebetween. The rear cover 32 has a substantially flat plate shape extending in the vertical direction. The lower end portion of the rear cover 32 is disposed below the low voltage power supply unit 31. The rear cover 32 has a curved portion 32A.

  The curved portion 32 </ b> A is disposed at the lower end portion of the rear cover 32. The curved portion 32A is a protrusion that protrudes forward from the inner surface of the rear cover 32, that is, the front surface, and extends in the vertical direction. The front end edge of the curved portion 32A is curved so as to go forward as it goes downward in a side view. The front end edge of the lower end portion of the curved portion 32A is disposed in front of the upper end edge E1 (see FIG. 4) of the lower wall 54 described later of the side guide 34.

  Each of the pair of transport rollers 35 is disposed above the fixing unit 6. The front conveyance roller 35 of each of the pair of conveyance rollers 35 is supported inside the main body casing 2 so as to be able to rotate forward and backward. The rear conveyance roller 35 of each of the pair of conveyance rollers 35 is supported by the rear cover 32 so as to be rotatable forward and backward, and is in contact with the rear end portion of the front conveyance roller 35.

  The lower frame 33 is disposed below the paper feed tray 7 as shown in FIGS. The lower frame 33 has a substantially flat plate shape extending in the front-rear direction. The lower frame 33 has a plurality of guide ribs 40, an engagement portion 41, and a screwing portion 42.

  Each of the plurality of guide ribs 40 is a protrusion that protrudes upward from the upper surface of the lower frame 33 and extends in the front-rear direction. Each of the plurality of guide ribs 40 is arranged in parallel at intervals in the left-right direction. The upper end edge of each rear end portion of the plurality of guide ribs 40 is curved upward as it goes rearward.

  As shown in FIGS. 2 and 3, the engaging portion 41 is disposed on the left side of the plurality of guide ribs 40 at the left rear end portion of the lower frame 33. The engaging portion 41 has a plurality of, specifically, three ribs 41A.

  Each of the plurality of ribs 41A is a protrusion that protrudes upward from the upper surface of the lower frame 33 and extends in the front-rear direction. Each of the plurality of ribs 41A is arranged in parallel with an interval in the left-right direction.

  The screwing portion 42 is disposed in front of the engaging portion 41. The screw portion 42 has a substantially cylindrical shape protruding upward from the upper surface of the lower frame 33.

  As shown in FIGS. 1 and 4, the side guide 34 is disposed in front of the rear cover 32 and above the rear end portion of the lower frame 33. The side guide 34, together with the low-voltage power supply unit 31, the rear cover 32, the pair of transport rollers 35, the paper feed tray 7, and the lower frame 33, constitutes a transport mechanism that transports the paper P in the reverse path. The side guide 34 has a guide part 51 and a fixing part 53.

  The guide 51 includes a lower wall 54 as an example of a first wall, an upper wall 55 as an example of a second wall, and a side wall 56 as an example of a third wall.

  The lower wall 54 is disposed substantially at the center in the vertical direction of the side guide 34. The lower wall 54 has a curved plate shape that curves forward as it goes downward. The rear upper end portion of the lower wall 54 faces the lower side of the lower end portion of the rear cover 32 behind the front end edge of the curved portion 32A of the rear cover 32. That is, the rear upper end portion of the lower wall 54 overlaps the curved portion 32A when viewed in the vertical direction.

  The upper wall 55 is disposed to face the upper front of the lower wall 54 with a space therebetween. That is, the upper wall 55 is disposed inward of the curve of the lower wall 54. The upper wall 55 has a first portion 55A, a second portion 55B, and a third portion 55C.

  The first portion 55 </ b> A is disposed at the upper end portion of the upper wall 55. The first portion 55A has a flat plate shape that linearly extends in the vertical direction. The upper end portion of the first portion 55 </ b> A is located above the upper end portion of the lower wall 54. The first portion 55A faces the front of the curved portion 32A of the rear cover 32.

  The second portion 55B has a flat plate shape that extends straight forward and downward from the lower end of the first portion 55A. That is, the second portion 55B is inclined forward as it goes downward. A continuous portion 55D of the first portion 55A and the second portion 55B is located below the upper end edge E1 of the lower wall 54. The shortest distance D2 between the lower portion 54 and the continuous portion 55D of the first portion 55A and the second portion 55B is shorter than the longitudinal distance D1 between the first portion 55A and the upper edge E1 of the lower wall 54.

  The third portion 55C has a curved plate shape that extends continuously from the lower end of the second portion 55B while curving forward and downward. The shortest distance D3 between the continuous portion 55E between the second portion 55B and the third portion 55C and the lower wall 54 is longer than the shortest distance D2 between the continuous portion 55D between the first portion 55A and the second portion 55B and the lower wall 54. short. The vertical distance D4 between the front end of the third portion 55C and the front end of the lower wall 54 is shorter than the shortest distance D3 between the continuous portion 55E between the second portion 55B and the third portion 55C and the lower wall 54. .

  The side wall 56 is disposed at the left end portion of the guide portion 51 as shown in FIGS. 5A and 6. The side wall 56 has a substantially flat plate shape extending in the vertical direction. The front end portion of the side wall 56 is continuous with the left end portion of the upper wall 55. The rear end portion of the side wall 56 is continuous with the left end portion of the lower wall 54. The upper end edge E3 of the side wall 56 has a first end edge E31, a second end edge E32, and a third end edge E33. The first end edge E31 is continuous with the left end portion of the upper end edge E1 of the lower wall 54 and extends along the front-rear direction. The second end edge E32 is continuous with the left end portion of the upper end edge E2 of the upper wall 55 and extends along the front-rear direction. The third end edge E33 continuously extends from the front end portion of the first end edge E31 to the front upper side and is continuous with the rear end portion of the second end edge E32. That is, the third end edge E33 is inclined backward as it goes downward. The side wall 56 has a first restricting portion 56A and a second restricting portion 56B.

  The first restricting portion 56 </ b> A constitutes the rear half of the side wall 56. 56 A of 1st control parts have the substantially flat plate shape extended in an up-down direction.

  The second restricting portion 56 </ b> B constitutes the front half of the side wall 56. The second restricting portion 56B has a substantially flat plate shape that extends continuously from the front end portion of the first restricting portion 56A to the right front. That is, the 2nd control part 56B inclines rightward as it goes ahead. A continuous portion 56C of the first restricting portion 56A and the second restricting portion 56B is disposed in the vicinity of the rear of the first portion 55A of the upper wall 55 so as to overlap the second end edge E32 of the side wall 56 when viewed in the vertical direction. ing.

  As shown in FIG. 5B, the fixing portion 53 is disposed on the lower left side of the side guide 34. The fixing portion 53 has a substantially rectangular shape when viewed from the bottom. The fixing portion 53 includes an engaging rib 52 as an example of a positioning portion and a screw insertion hole 57.

  The engaging rib 52 is disposed at the approximate center of the fixing portion 53 in the front-rear direction. The engagement rib 52 protrudes downward from the lower surface of the fixed portion 53 and has a substantially flat plate shape extending in the front-rear direction. With reference to FIGS. 3 and 5B, the engagement rib 52 fits between two adjacent ribs 41 </ b> A among the plurality of ribs 41 </ b> A of the lower frame 33. That is, when the engaging rib 52 is fitted between the right rib 41A and the central rib 41A, the side guide 34 is disposed relatively to the right. When the engaging rib 52 is fitted between the left rib 41A and the central rib 41A, the side guide 34 is disposed relatively to the left. Accordingly, the position of the side guide 34 in the left-right direction with respect to the lower frame 33 is determined according to the specifications of the printer 1, specifically, the length in the left-right direction of the maximum paper P that can form an image, ie, the maximum paper width. . More specifically, when the side guide 34 is disposed relatively to the right, the side guide 34 guides the A4 size paper P. In addition, when the side guide 34 is disposed relatively to the left, the side guide 34 is positioned to the left of the case where the A4 size is guided, and the letter P is wider in the left-right direction than the A4 size. To guide.

The screw insertion hole 57 is disposed in front of the engagement rib 52. The screw insertion hole 57 is a long hole extending in the left-right direction, and penetrates the fixing portion 53 in the up-down direction. The side guide 34 is fixed to the left rear end portion of the lower frame 33 by screwing a screw (not shown) into the screwing portion 42 via the screw insertion hole 57.
3. Conveyance of Paper in Reverse Path With reference to FIGS. 1 and 4, the conveyance of paper in the reverse path will be described.

  In the image forming operation described above, the paper P on which the toner image is fixed is, as indicated by the phantom line in FIG. It is introduced between the fixing unit 6 and the rear cover 32 so that the fixed first surface faces forward.

  Thereafter, the paper P passes between the fixing unit 6 and the rear cover 32 from the upper side to the lower side, and is introduced between the rear end portion of the lower frame 33 and the rear end portion of the paper feed tray 7.

  At this time, as indicated by phantom lines in FIG. 4, the left end portion of the paper P is guided forward by the curved portion 32 </ b> A of the rear cover 32 so as to go downward, and the first portion 55 </ b> A of the upper wall 55. It is introduced between the curved portion 32A.

  Next, the left end portion of the paper P is guided in the vertical direction along the first portion 55 </ b> A of the upper wall 55, and is introduced between the second portion 55 </ b> B and the lower wall 54.

  At this time, the sheet P is restricted from moving leftward by the first restricting portion 56 </ b> A of the side wall 56.

  Next, the left end portion of the sheet P is guided forward and downward along the curve of the lower wall 54. That is, the left end portion of the paper P passes through the fixing unit 6 and is conveyed downward, and then is changed in direction so as to go forward. Thereafter, the left end portion of the sheet P passes between the third portion 55C and the lower wall 54 and is conveyed forward.

  At this time, the sheet P is conveyed forward while being gradually moved rightward by the second restricting portion 56 </ b> B of the side wall 56.

  It should be noted that portions other than the left end portion of the paper P are guided forward by the guide rib 40 of the lower frame 33 so as to go forward as it goes downward, and then conveyed forward.

Thereafter, the sheet P is moved from the rear to the front between the sheet feeding tray 7 and the lower frame 33 with the second surface opposite to the first surface on which the toner image is fixed facing downward. Then, the paper is passed through the front end portion of the paper feed tray 7 and turned upward, and is supplied between the foremost photosensitive drum 11 and the conveyor belt 17 so that the second surface faces upward.
4). Operation and Effect (1) According to the printer 1, as shown in FIGS. 1 and 4, the sheet P conveyed downward between the low-voltage power supply unit 31 and the rear cover 32 is transferred to the first wall 55. It can be introduced between the lower wall 54 and the upper wall 55 along the portion 55A.

  Therefore, when the paper P is introduced between the lower wall 54 and the upper wall 55, the paper P can be prevented from coming into contact with the upper edge E1 of the lower wall 54 and the upper edge E2 of the upper wall 55.

As a result, the paper P can be reliably introduced between the lower wall 54 and the upper wall 55 and can be smoothly turned.
(2) According to the printer 1, as shown in FIG. 4, the lower end portion of the rear cover 32 is disposed to face the upper portion of the lower wall 54, and is spaced behind the first portion 55A of the upper wall 55. Facing each other.

Therefore, the paper P can be reliably introduced between the lower wall 54 and the upper wall 55 by passing between the lower end portion of the rear cover 32 and the first portion 55 </ b> A of the upper wall 55.
(3) According to the printer 1, as shown in FIG. 4, the curved portion 32A of the rear cover 32 overlaps with the upper end portion of the lower wall 54 when viewed from above.

  Therefore, the curved portion 32A can guide the paper P forward as it goes downward.

  Thereby, the paper P can be introduced between the lower wall 54 and the upper wall 55 in front of the lower wall 54.

As a result, the sheet P guided by the rear cover 32 can be prevented from coming into contact with the upper edge E1 of the lower wall 54.
(4) According to the printer 1, as shown in FIG. 5A, the upper end edge E3 of the side wall 56 is continuous with the upper end edge E1 of the lower wall 54 and the upper end edge E2 of the upper wall 55.

As a result, when the paper P is introduced between the lower wall 54 and the upper wall 55, the side wall 56 can prevent the paper P from shifting to the left.
(5) According to the printer 1, as shown in FIG. 5A, the upper end edge E3 of the side wall 56 is bent, and therefore has higher rigidity than the case where it is not bent.

For this reason, when the paper P is introduced between the lower wall 54 and the upper wall 55, the side wall 56 can more reliably restrict the paper P from shifting to the left.
(6) According to the printer 1, as shown in FIG. 5A and FIG. 6, the side wall 56 is continuous with the first restricting portion 56A extending along the vertical direction and the first restricting portion 56A, and as it goes forward. And a second restricting portion 56B extending inclined to the right.

For this reason, the first restricting portion 56A can restrict the sheet P conveyed downward from shifting to the left, and then the second restricting portion 56B can move the sheet P conveyed forward to the right. .
(7) According to the printer 1, as shown in FIG. 4, the lower wall 54 curves forward as it goes downward, whereas the second portion 55B of the upper wall 55 moves forward as it goes downward. It extends linearly so as to incline toward.

  Therefore, the space between the curved lower wall 54 and the linear second portion 55B can be set wider than when the second portion 55B is curved.

As a result, the direction of the paper P can be smoothly changed.
(8) According to the printer 1, as shown in FIGS. 3 and 5B, the engagement rib 52 fits between two adjacent ribs 41A among the plurality of ribs 41A of the lower frame 33.

  Accordingly, the side guide 34 can be positioned in the left-right direction with respect to the lower frame 33 without providing a separate member.

  Therefore, the side guide 34 can be accurately arranged with respect to the lower frame 33.

As a result, the paper P can be smoothly transferred from the side guide 34 to the lower frame 33.
(9) According to the printer 1, as shown in FIG. 1, the side guide 34 guides the first forward change of the paper P conveyed downward by the conveyance mechanism.

  Therefore, the paper P that has passed through the fixing unit 6 can be reliably introduced between the lower wall 54 and the upper wall 55 and can be smoothly turned.

DESCRIPTION OF SYMBOLS 1 Printer 5 Transfer unit 6 Fixing unit 7 Feed tray 11 Photosensitive drum 31 Low voltage power supply unit 32 Rear cover 32A Curved part 33 Lower frame 34 Side guide 35 Conveying roller 52 Engaging rib 54 Lower wall 55 Upper wall 55A First part 55B Second part Part 55C Third part 56 Side wall 56A First restriction part 56B Second restriction part E1 Upper edge E2 Upper edge E3 Upper edge E31 First edge E32 Second edge E33 Third edge P Paper

Claims (9)

A first guide member configured to guide a recording medium conveyed toward a predetermined first direction;
While guiding the recording medium disposed downstream of the first guide member and transported in the first direction with respect to the first guide member so as to change direction in a second direction different from the first direction. A second guide member configured to regulate a position in the width direction of the recording medium to be conveyed;
A third guide member arranged downstream of the second direction with respect to the second guide member and configured to guide a recording medium conveyed toward the second direction;
The second guide member is
A first wall that curves in the second direction as it goes downstream in the first direction;
A second wall disposed to face the first wall at an interval inward of the curvature of the first wall;
A third wall continuous to the one end in the width direction of the first wall and the one end in the width direction of the second wall;
The upstream end portion in the first direction of the second wall is located upstream of the upstream end portion in the first direction of the first wall in the first direction. . The downstream end of the first guide member in the first direction is disposed upstream of the first direction with respect to the first wall, and the upstream end of the second wall with respect to the upstream end of the first direction. The image forming apparatus according to claim 1, wherein the image forming apparatuses face each other at an interval in the second direction. The downstream end of the first guide member in the first direction has a curved portion that curves in the second direction as it goes downstream in the first direction,
The image forming apparatus according to claim 1, wherein the curved portion overlaps an upstream end portion of the first wall in the first direction when viewed from the first direction. The upstream edge of the third wall in the first direction is continuous with the upstream edge of the first wall in the first direction and the upstream edge of the second wall in the first direction. The image forming apparatus according to claim 1, wherein the image forming apparatus is characterized. An upstream edge of the third wall in the first direction is
A first edge that is continuous with an upstream edge of the first wall in the first direction and extends in a direction perpendicular to the first direction;
A second edge that is continuous with an upstream edge of the second wall in the first direction and extends in a direction perpendicular to the first direction;
5. The apparatus according to claim 1, further comprising a third end edge that is continuous with the first end edge and the second end edge and extends in a direction inclined with respect to the first direction. The image forming apparatus described in the item. The third wall is
A first restricting portion extending along the first direction;
A second restricting portion that is continuous with the first restricting portion and extends obliquely toward the other of the width direction from the position overlapping the second end edge when viewed in the first direction toward the second direction; The image forming apparatus according to claim 5, further comprising: The second wall is
A first portion extending linearly along the first direction;
A second portion extending linearly so as to incline in the second direction toward the first direction continuously to the first portion;
7. The image forming apparatus according to claim 1, further comprising a third portion that extends continuously while being curved in the second direction. The image forming apparatus according to claim 1, wherein the second guide member includes a positioning portion for determining a position of the second guide member with respect to the third guide member. . An image carrier configured to carry a developer image;
A transfer device configured to transfer the developer image carried on the image carrier facing the image carrier to a recording medium;
A fixing device configured to heat the recording medium onto which the developer image has been transferred to fix the developer image on the recording medium;
A transport mechanism configured to transport the recording medium that has passed through the fixing device between the image carrier and the transfer device;
The said 2nd guide member is comprised so that the first direction change to the said 2nd direction of the recording medium conveyed in the said 1st direction by the said conveyance mechanism may be guided. The image forming apparatus as described in any one of -8.

Images