CN116893591A - Image forming apparatus having a plurality of image forming units - Google Patents

Abstract

The present invention relates to an image forming apparatus. The image forming apparatus includes: a first conveying guide portion including a first roller, a first engaging portion, and a second engaging portion; and a second conveying guide portion including a second roller, a first engaged portion, and a second engaged portion. The first conveying guide portion and the second conveying guide portion form a conveying path in which the first roller and the second roller convey the sheet. The second conveying guide portion moves so that engagement between the second engaging portion and the second engaged portion is released, and relative positioning between the second conveying guide portion and the first conveying guide portion is released. When the first engaging portion and the first engaged portion are engaged with each other and the relative positioning between the second conveying guide portion and the first conveying guide portion is released, the second conveying guide portion is scratched in the opening direction with respect to the first conveying guide portion, thereby opening the conveying path.

Description

Image forming apparatus having a plurality of image forming units

Technical Field

The present invention relates to an image forming apparatus including a sheet conveying guide.

Background

Among image forming apparatuses that form an image on a recording material such as a sheet using an image forming process such as an electrophotographic process, there is an image forming apparatus provided with a conveyance guide portion that can be opened and closed by a user to replace a conveyance roller or remove a jammed recording material. As such a conveying guide, there is a conveying guide including a pivot shaft at one end of the conveying guide on an upstream or downstream side in a conveying direction of a recording material and provided with a lock member at the other end on a main body side or in the conveying guide for the conveying guide as discussed in japanese patent application laid-open No. 2005-315920.

Disclosure of Invention

The present invention relates to a structure for opening a conveyance path by opening a conveyance guide, and an object of the present invention is to provide an image forming apparatus having excellent usability in opening the conveyance guide. In an example, when the second conveying guide moves in a predetermined direction relative to the first conveying guide, the positioning of the second conveying guide relative to the first conveying guide is released, and the second conveying guide is scratched relative to the first conveying guide, thereby opening the conveying path.

According to one aspect of the present invention, an image forming apparatus configured to form an image on a sheet includes: a first conveying guide portion including a first roller, a first engaging portion, and a second engaging portion; and a second conveying guide portion including a second roller, a first engaged portion configured to engage with the first engaging portion, and a second engaged portion configured to engage with the second engaging portion. Wherein the first conveying guide and the second conveying guide form a conveying path that conveys the sheet in a state in which the second conveying guide is positioned at a predetermined position with respect to the first conveying guide, and the first roller and the second roller contact each other to convey the sheet. Wherein in a state where the first engaging portion and the first engaged portion are engaged with each other, the second conveying guide portion is configured to move in a predetermined direction with respect to the first conveying guide portion, so that the engagement between the second engaging portion and the second engaged portion is released and the positioning of the second conveying guide portion with respect to the first conveying guide portion is released. Wherein in a state in which the first engaging portion and the first engaged portion are engaged with each other and the positioning of the second conveying guide portion with respect to the first conveying guide portion is released, the second conveying guide portion is configured to pivot in an opening direction with respect to the first conveying guide portion, thereby opening the conveying path.

Other features of the present invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings.

Drawings

Fig. 1 is a cross-sectional view of an image forming apparatus according to a first exemplary embodiment.

Fig. 2 is a cross-sectional view of a duplex conveying unit according to a first exemplary embodiment.

Fig. 3 is a side view of the duplex conveying unit according to the first exemplary embodiment.

Fig. 4A and 4B are side views of the duplex conveying unit according to the first exemplary embodiment.

Fig. 5A and 5B are side views of the duplex conveying unit according to the first exemplary embodiment.

Fig. 6A and 6B are side views of the duplex conveying unit according to the first exemplary embodiment.

Fig. 7 is a side view of the duplex conveying unit according to the first exemplary embodiment.

Fig. 8 is a side view of the duplex conveying unit according to the first exemplary embodiment.

Fig. 9 is a side view of the duplex conveying unit according to the first exemplary embodiment.

Fig. 10A and 10B are side views of the duplex conveying unit according to the first exemplary embodiment.

Fig. 11A and 11B are side views of the duplex conveying unit according to the first exemplary embodiment.

Fig. 12A and 12B are side views of the duplex conveying unit according to the first exemplary embodiment.

Fig. 13 is a side view of the duplex conveying unit according to the first exemplary embodiment.

Fig. 14 is a cross-sectional view of the duplex conveying unit according to the first exemplary embodiment.

Fig. 15 is an external perspective view of the duplex conveying unit according to the first exemplary embodiment.

Fig. 16 is a cross-sectional view of a duplex conveying unit according to a second exemplary embodiment.

Fig. 17 is a side view of a duplex conveying unit according to a second exemplary embodiment.

Fig. 18A and 18B are side views of a duplex conveying unit according to a second exemplary embodiment.

Fig. 19A and 19B are side views of a duplex conveying unit according to a second exemplary embodiment.

Fig. 20A to 20C are side views of a duplex conveying unit according to a second exemplary embodiment.

Fig. 21 is a side view of a duplex conveying unit according to a second exemplary embodiment.

Fig. 22 is a side view of a duplex conveying unit according to a second exemplary embodiment.

Fig. 23A and 23B are detailed views of the duplex conveying unit according to the second exemplary embodiment.

Fig. 24A to 24D are detailed views of the duplex conveying unit according to the second exemplary embodiment.

Fig. 25A and 25B are side views of a duplex conveying unit according to a third exemplary embodiment.

Fig. 26 is a cross-sectional view of an image forming apparatus according to a fourth exemplary embodiment.

Fig. 27 is a cross-sectional view of a transfer unit according to a fourth exemplary embodiment.

Fig. 28 is a side view of a transfer unit according to a fourth exemplary embodiment.

Fig. 29 is a side view of a transfer unit according to a fourth exemplary embodiment.

Fig. 30 is a side view of a transfer unit according to a fourth exemplary embodiment.

Fig. 31A and 31B are side views of a transfer unit according to a fourth exemplary embodiment.

Fig. 32A and 32B are side views of a transfer unit according to a fourth exemplary embodiment.

Detailed Description

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. The following exemplary embodiments are not intended to limit the invention of the appended claims, and not all feature combinations described in the exemplary embodiments are necessary for the solution of the present invention.

Next, a first exemplary embodiment will be described.

< image Forming apparatus >

Fig. 1 is a cross-sectional view illustrating an electrophotographic laser printer having a double-sided image forming function as an example of an image forming apparatus according to the present exemplary embodiment. The size, materials, shape, and relative arrangement of the components described in the present exemplary embodiment are not intended to limit the scope of the present invention unless otherwise specified. The image forming apparatus according to the present exemplary embodiment is not limited to a laser printer but may be a copier, a facsimile machine, or any other type of image forming apparatus.

The image forming apparatus 101 shown in fig. 1 includes a sheet feeding unit, an image forming unit that forms an image on a sheet, a fixing unit, a sheet discharge reversing unit, and a duplex conveying unit.

The image forming apparatus 101 includes a process cartridge 1 attachable to and detachable from a main body of the image forming apparatus 101. The process cartridge 1 includes a photosensitive drum 2 and a process unit (not shown) such as a developing unit and a charging roller. The scanner unit 3 is placed above the process cartridge 1 in the vertical direction. The scanner unit 3 exposes the photosensitive drum 2 based on the image signal.

After the photosensitive drum 2 is charged to a potential having a predetermined negative polarity by a charging roller (not shown), the scanner unit 3 forms an electrostatic latent image on the photosensitive drum 2. The electrostatic latent image is reversely developed by a developing unit in the process cartridge 1, toner having a negative polarity adheres to the electrostatic latent image, and a toner image is formed on the photosensitive drum 2.

The sheet feeding unit includes a sheet feeding roller 4 attached to the image forming apparatus 101 and a sheet feeding cassette 5 attachable to and detachable from the main body of the image forming apparatus 101 and storing sheets S. The sheets S stored in the sheet feeding cassette 5 are separated and fed one by one from the sheet feeding cassette 5 by a sheet feeding roller 4 rotated by power of a sheet feeding driving unit (not shown). Each of the feed sheets S is conveyed by the conveying roller pair 6 to the registration roller pair 7, skew-corrected by the registration roller pair 7, and conveyed to the transfer unit.

In the transfer unit, a bias applying unit (not shown) applies a bias having a positive polarity to the transfer roller 8. Therefore, the toner image is transferred as an unfixed image to the sheet S to be conveyed to the transfer unit. The process cartridge 1 and the transfer roller 8 function as an image forming unit.

The sheet S to which the toner image is transferred is conveyed to a fixing device 9 as a fixing unit provided downstream of the transfer unit in the conveying direction of the sheet S. The fixing device 9 is for fixing the transferred toner image to the sheet S and includes a heating roller 10 and a pressure roller 11, the heating roller 10 being a fixing member heated by a heater as a heating unit (not shown) and the pressure roller 11 being a pressure member that rotates in pressure contact with the heating roller 10. When the fixing nip formed by the heat roller 10 and the pressure roller 11 nips and conveys the sheet S, heat and pressure are applied to the sheet S, thereby fixing the toner image to the front surface of the sheet S.

The sheet S to which the toner image is fixed is conveyed from the fixing device 9 to a sheet discharge reversing unit. The sheet discharge reversing unit includes a sheet discharge roller 13, a sheet discharge driven roller 14, a reverse driven roller 15, and a double-sided shutter 12. In the case of single-sided image formation (single-sided printing), the double-sided flapper 12 is held at a position (indicated by a solid line) at which the double-sided flapper 12 guides the sheet S to the side of a sheet discharge nip formed by the sheet discharge roller 13 and the sheet discharge driven roller 14, and the sheet S is discharged to the sheet discharge tray 16 by the sheet discharge roller 13 and the sheet discharge driven roller 14.

In the case of double-sided image formation (double-sided printing), the double-sided flapper 12 is held at a position (indicated by a broken line) at which the double-sided flapper 12 guides the sheet S to the side of the reverse nip formed by the sheet discharging roller 13 and the reverse driven roller 15, and the sheet S is conveyed to the reverse nip side by the fixing device 9. At the timing when the trailing edge of the sheet S reaches the predetermined position, the sheet discharging roller 13 is reversely rotated by a rotation direction switching unit (not shown).

Accordingly, the sheet S passes through the duplex conveying roller pair 17 (first duplex conveying roller 17b and second duplex conveying roller 17a in fig. 2) and the sheet refeeding roller pair 18 (first sheet refeeding roller 18a and second sheet refeeding roller 18b in fig. 2) with the trailing edge at the head, and is conveyed again to the registration roller pair 7 in a state where the front and back sides are reversed. Then, similarly to the one-sided printing, skew of the sheet S is corrected by the registration roller pair 7, an image is transferred onto the sheet S by the transfer roller 8, and the image is fixed onto the sheet S by the fixing device 9. Then, the sheet S is discharged to the sheet discharge tray 16 by the sheet discharge roller 13 and the sheet discharge driven roller 14, whereby double-sided printing is completed.

< double-sided delivery Unit >

Next, the configuration of the duplex conveying unit 201 shown in fig. 1 will be described with reference to fig. 2 to 15. Fig. 2 and 3 and fig. 7 to 9 are side views of the duplex conveying unit 201. Fig. 4A to 6B and fig. 10A to 13 are enlarged views including at least one of the first engaged portion, the second engaged portion, and the second engaged portion.

As shown in fig. 3, the duplex conveying unit 201 includes a first conveying guide 202 and a second conveying guide 203 as guide portions. The first conveying guide 202 and the second conveying guide 203 form a conveying path 21 that conveys the sheet S. The conveying path 21 is a conveying path that conveys the sheet S to form an image on the other side of the sheet S after the image is formed on the front side.

The first conveying guide 202 guides the upper surface of the conveyed sheet S. The first conveying guide 202 is located above the second conveying guide 203 in the vertical direction. The second conveying guide 203 guides the lower surface of the conveyed sheet S. The second conveying guide 203 is located below the first conveying guide 202 in the vertical direction.

The first conveying guide 202 includes a first duplex conveying roller 17b as a first roller and a first sheet refeeding roller 18a as a third roller. The first conveyance guide 202 further includes a long hole 202a as a first engaging portion and a groove 202b as a second engaging portion that engages with a protruding portion (described below). The long hole 202a and the groove 202b are provided on one end side of the first conveying guide 202 in the axial direction of the first duplex conveying roller 17 b. The long hole 202a and the groove 202b are also provided on the other end side of the first conveying guide 202 in the axial direction of the first duplex conveying roller 17 b.

Fig. 2 and 3 are cross-sectional views of the first conveying guide 202 as viewed from a direction intersecting the conveying direction of the sheet S, and thus only one long hole 202a and one groove 202b on one end side of the first conveying guide 202 are illustrated. However, one long hole 202a and one groove 202b are also provided on the other end side of the first conveyance guide 202.

The second conveying guide 203 includes a second duplex conveying roller 17a as a second roller that can contact and separate from the first duplex conveying roller 17 b. The second conveying guide 203 further includes a second sheet refeeding roller 18b as a fourth roller. As shown in fig. 4A and 4B, the second conveyance guide part 203 further includes an engagement protrusion 203a as a first engaged part engaged with the first engagement part and a positioning protrusion 203B as a second engaged part engaged with the second engagement part.

The engaging protrusion 203a and the positioning protrusion 203b are protruding portions protruding from the second conveyance guide 203. The engaging protrusion 203a and the positioning protrusion 203b are provided on one end side of the second conveying guide 203 in the axial direction of the first duplex conveying roller 17b of the first conveying guide 202. The engaging protrusion 203a and the positioning protrusion 203b are also provided on the other end side of the second conveying guide 203 in the axial direction of the first duplex conveying roller 17b of the first conveying guide 202.

In a state where the second conveying guide 203 is positioned at a predetermined position with respect to the first conveying guide 202, the first conveying guide 202 and the second conveying guide 203 form a conveying path 21, and the first duplex conveying roller 17b and the second duplex conveying roller 17a contact each other to convey the sheet S. At this time, the first sheet refeeding roller 18a and the second sheet refeeding roller 18b also contact each other to convey the sheet S. As shown in fig. 2, the second sheet refeeding roller 18b is biased toward the first sheet refeeding roller 18a by a sheet refeeding roller spring 18c as a roller biasing portion.

As shown in fig. 3, a state in which the first conveying guide 202 and the second conveying guide 203 are positioned at predetermined positions will be described in more detail. When the first conveying guide 202 and the second conveying guide 203 are positioned at predetermined positions, the engagement protrusion 203a is engaged with the long hole 202a and is located on the right end side of the long hole 202a extending in the direction of the conveying path 21 of the sheet S (in fig. 3).

When the second conveying guide 203 is positioned at a predetermined position with respect to the first conveying guide 202, the positioning protrusion 203b is engaged with the groove 202 b. The positioning protrusion 203b is positioned toward the inside of the groove 202 b. The positioning protrusion 203b is positioned in the groove 202b by a force generated due to the self weight of the second conveying guide 203 or a reaction force of the second sheet refeeding roller 18b biased by the sheet refeeding roller spring 18 c. In other words, the groove 202b receives the self weight of the second conveying guide 203 or the reaction force of the second sheet refeeding roller 18b biased by the sheet refeeding roller spring 18c via the positioning protrusion 203 b.

Next, the opening of the duplex conveying unit 201 will be described. As shown in fig. 7, the duplex conveying unit 201 may open the conveying path 21. More specifically, the engagement between the positioning protrusion 203b and the groove 202b is released, and the second conveying guide 203 pivots about the engagement protrusion 203a with respect to the first conveying guide 202, thereby opening the conveying path 21. The direction in which the second conveying guide 203 pivots with respect to the first conveying guide 202 at this time is referred to as an "opening direction". The direction opposite to the opening direction is referred to as the "closing direction".

At this time, the second conveying guide 203 moves in a direction away from the conveying path 21, whereby the first duplex conveying roller 17b and the second duplex conveying roller 17a are separated from each other.

If the sheet S is jammed in the duplex conveying unit 201, a user or a serviceman can remove the jammed sheet S by opening the conveying path 21. The user or maintenance personnel can also replace the rollers attached to the first conveying guide 202 or the second conveying guide 203.

In a state where the positioning protrusion 203b is positioned in the groove 202b, the second conveyance guide 203 cannot pivot. On the other hand, in a state in which the engagement protrusion 203a and the long hole 202a are engaged with each other and the positioning between the first conveying guide portion 202 and the second conveying guide portion 203 is released, the second conveying guide portion 203 can pivot with respect to the first conveying guide portion 202. The opening direction is a direction in which the second conveying guide 203 pivots relative to the first conveying guide 202 under its own weight.

The positioning of the positioning projection 203b can be released by detaching the sheet feeding cassette 5 and moving (translating) the second conveying guide 203 in a predetermined direction with respect to the first conveying guide 202. In the present exemplary embodiment, the predetermined direction is a direction opposite to the conveying direction (indicated by an arrow A1) of the sheet S. The "conveyance direction of the sheet S" used herein refers to a conveyance direction in which the sheet S is conveyed by the first duplex conveying roller 17b and the second duplex conveying roller 17 a. When the second conveying guide 203 moves in the opposite direction, the position of the engagement protrusion 203a is also shifted to the left side of the long hole 202a (the direction indicated by the arrow A2 in fig. 3). In other words, in a state where the engagement protrusion 203a and the long hole 202a are engaged with each other, the second conveyance guide 203 can move in a predetermined direction (opposite direction) with respect to the first conveyance guide 202. In other words, in a state in which the engagement protrusion 203a and the long hole 202a are engaged with each other, the second conveying guide 203 is movable (translatable) so as to be displaced in the conveying direction and the opposite direction of the sheet S with respect to the first conveying guide 202. This results in switching between a state in which the groove 202b and the positioning protrusion 203b are engaged with each other and a state in which the engagement between the groove 202b and the positioning protrusion 203b is released.

The engagement protrusion 203a and the long hole 202a are located upstream of the groove 202b and the positioning protrusion 203b in the conveying direction of the sheet S. The second conveyance guide 203 can be moved by pressing the handle portion 203c in the direction indicated by the arrow A2, the handle portion 203c being a pressing portion of the second conveyance guide 203 in fig. 2. When the second conveying guide 203 is moved in a predetermined direction (opposite direction), the engagement between the groove 202b and the positioning protrusion 203b is released, and the positioning of the second conveying guide 203 with respect to the first conveying guide 202 is released. In other words, pressing the pressing portion causes the second conveying guide 203 to move in a direction in which the engagement between the groove 202b and the positioning protrusion 203b is released.

When the engagement between the groove 202b and the positioning protrusion 203b is released and the second conveying guide 203 pivots with respect to the first conveying guide 202, the conveying path 21 is opened. In other words, the positioning of the second conveying guide 203 with respect to the first conveying guide 202 is released, the engagement between the groove 202b and the positioning protrusion 203b is released, and the second conveying guide pivots with respect to the first conveying guide, thereby opening the conveying path 21.

Next, the engagement between the groove 202b and the positioning protrusion 203b when the conveying path 21 is opened will be described in more detail. When the user presses the handle portion 203c toward the direction indicated by the arrow A2, as shown in fig. 4A, the positioning protrusion 203b climbs up the first guide portion 202b1 of the groove 202 b. At this time, as shown in fig. 4B, the engagement protrusion 203a moves leftward in the long hole 202 a. When the user further pushes the handle portion 203c in the direction indicated by the arrow A2, as shown in fig. 5A, 5B, 6A, and 6B, the positioning protrusion 203B climbs over the first guide portion end 202B6 in a state where the engagement protrusion 203a and the long hole 202a are engaged with each other. Then, the positioning protrusion 203B moves in the direction indicated by the broken line arrow B in fig. 6A, and the second conveyance guide 203 opens.

Next, an operation of closing the conveying path 21 will be described. After the user lifts the second conveying guide 203 in the open state shown in fig. 7, the groove 202b and the positioning protrusion 203b are engaged with each other, and the second conveying guide 203 is positioned with respect to the first conveying guide 202, thereby closing the conveying path 21. At this time, as shown in fig. 8 and 9, the pivot trajectories L1 and L2 of the positioning projection 203b differ depending on the position of the engagement projection 203a with respect to the long hole 202 a.

As shown in fig. 8, if the second conveying guide 203 is lifted in a state where the second conveying guide 203 is pulled out in the conveying direction of the sheet S, the engagement protrusion 203a is located at one end portion of the long hole 202a, and the positioning protrusion 203b is in contact with the fourth guide 202b4 shown in fig. 10A. As shown in fig. 9, if the second conveyance guide 203 is lifted in a state where the second conveyance guide 203 is pushed in the opposite direction, the engagement protrusion 203a is located at the other end portion of the long hole 202a, and the positioning protrusion 203b is in contact with the third guide 202b3 shown in fig. 11A.

As shown in fig. 10A and 10B, if the second conveying guide portion 203 is lifted in a state where the engaging protrusion 203a is located at one end portion of the long hole 202a and the positioning protrusion 203B is in contact with the fourth guide portion 202B4, the positioning protrusion 203B is lifted upward along the fourth guide portion 202B4 in the direction indicated by the arrow A3 and is in contact with the third guide portion 202B3 shown in fig. 11A. At this time, the second conveying guide 203 moves in the direction from the positioning position to the release position.

As shown in fig. 11A and 11B, in a state where the engagement protrusion 203a is engaged with the long hole 202a, the positioning protrusion 203B in contact with the third guide portion 202B3 is lifted along the third guide portion 202B3 in the direction indicated by the arrow A4. At this time, the second conveying guide 203 moves in the direction from the release position to the positioning position. If the second conveying guide 203 continues to be lifted, as shown in fig. 12A and 12B, the positioning protrusion 203B reaches the contact surface 202B5 of the groove 202B in a state where the engagement protrusion 203a is engaged with the long hole 202A. At this time, as shown in fig. 13, the shaft center 203b1 of the positioning projection 203b is configured downstream of the first guide end 202b6 of the groove 202b by L3 in the conveying direction.

Further, when the positioning projection 203b is in contact with the contact surface 202b5 of the groove 202b as shown in fig. 13, an arrow A5-2 indicating the direction of the reaction force of the sheet refeeding roller spring 18c acting on the shaft center 203b1 of the positioning projection 203b overlaps the range W as shown in fig. 13. Therefore, if the user releases the force on the positioning protrusion 203b in a state where the positioning protrusion 203b is lifted up to the contact surface 202b5, the positioning protrusion 203b is positioned in the groove 202b, and the duplex conveying unit 201 enters the closed state.

In the present exemplary embodiment, the range W is a line from a line connecting the shaft center 203b1 of the positioning protrusion 203b and the first guide portion end 202b6 to a second guide portion 202b2 perpendicular to the groove 202b through the shaft center 203b1 of the positioning protrusion 203 b.

In a state where the second conveying guide 203 is positioned relative to the first conveying guide 202, two portions (two contact portions) of the positioning protrusion 203b are in contact with a portion (a portion where the groove 202b is formed) of the first conveying guide 202. The reaction force indicated by the arrow A5-2 acts such that the two contact portions of the positioning projection 203b are pressed against the portion of the first conveying guide 202 (the portion where the groove 202b is formed).

As shown in fig. 15, the visibility and operability can be improved by a label 203c1 attached to the handle portion 203c of the second conveyance guide portion 203, the label 203c1 carrying a graphic or character prompting the user to perform an operation.

As described above, in a state where the engagement protrusion 203a and the long hole 202a are engaged with each other, the second conveyance guide 203 can be moved in a predetermined direction to the positioning position and the release position with respect to the first conveyance guide 202.

As shown in fig. 3, the second conveying guide 203 is positioned relative to the first conveying guide 202 while the second conveying guide 203 is in a positioning position relative to the first conveying guide 202. In this state, the groove 202b and the positioning protrusion 203b are engaged with each other, and the second conveying guide 203 is restricted from pivoting in the opening direction with respect to the first conveying guide 202. In other words, a portion of the first conveying guide 202 is downstream of a portion of the second conveying guide 203 with respect to the opening direction of the wire-wrap engagement protrusion 203 a.

The first duplex conveying roller 17b and the second duplex conveying roller 17a contact each other to convey the sheet S while the second conveying guide 203 is in a positioning position with respect to the first conveying guide 202. Further, the first conveying guide 202 and the second conveying guide portion 203 form a conveying path 21.

On the other hand, as shown in fig. 6A and 6B, while the second conveying guide 203 is in the release position with respect to the first conveying guide 202, the engagement protrusion 203a and the long hole 202a are engaged with each other, and the engagement between the groove 202B and the positioning protrusion 203B is released. In this state, the second conveying guide 203 is allowed to pivot in the opening direction with respect to the first conveying guide 202. In a state where the engagement protrusion 203a and the long hole 202a are engaged with each other, the second conveying guide 203 is pivoted in the opening direction from the release position with respect to the first conveying guide 202, thereby opening the conveying path 21.

In a state where the engagement protrusion 203a and the long hole 202a are engaged with each other, when the second conveying guide 203 moves in a predetermined direction with respect to the first conveying guide 202, the engagement between the groove 202b and the positioning protrusion 203b is released. Then, the positioning of the second conveying guide 203 with respect to the first conveying guide 202 is also released. The predetermined direction may be referred to as "a direction from the positioning position to the releasing position". When the second conveying guide 203 moves from the positioning position to the releasing position, the second duplex conveying roller 17a moves relative to the first duplex conveying roller 17b. More specifically, the second duplex conveying roller 17a moves in a direction intersecting the rotation axis direction of the first duplex conveying roller 17b. When the second conveying guide 203 is in the release position, the second duplex conveying roller 17a is away from the first duplex conveying roller 17b.

In the present exemplary embodiment, the second conveyance guide 203 is configured to move relative to the first conveyance guide 202 and the main body. Alternatively, the first conveying guide 202 may be configured to move relative to the second conveying guide 203.

As described above, the movement of the second conveying guide 203 itself with respect to the first conveying guide 202 can release the positioning of the second conveying guide 203 with respect to the first conveying guide 202 and pivot the second conveying guide 203 with respect to the first conveying guide 202. The second conveying guide 203 itself moves relative to the first conveying guide 202 so that the positioning is released eliminating the need to unlock another member, thereby providing excellent usability. Further, since it is not necessary to separately provide the locking member, it is also possible to achieve cost reduction and miniaturization. Further, the reduction in the number of parts reduces the influence of the tolerance, and also increases the positioning accuracy of the second conveying guide 203 with respect to the first conveying guide 202.

The second exemplary embodiment will be described with reference to fig. 16 to 24D. Fig. 18A to 20C and fig. 23A to 24D are enlarged views including at least one of the first engaged portion, the second engaged portion, and the second engaged portion.

Components and functions similar to those in the first exemplary embodiment will not be described again, and features of the present exemplary embodiment will be mainly described. As shown in fig. 17, the image forming apparatus according to the present exemplary embodiment includes a biasing spring 304 as a biasing member that biases the second conveyance guide 303 in the direction indicated by the arrow A1.

< double-sided delivery Unit >

As shown in fig. 17, the engaging protrusion 303a provided on the upstream side of the second conveying guide 303 in the conveying direction is held in the long hole 302a of the first conveying guide 302. A biasing spring 304 as a biasing member for biasing the second conveying guide 303 in the conveying direction of the sheet S is provided between the spring holding portion 303d of the second conveying guide 303 and the frame spring holding portion 302c of the first conveying guide 302. The direction in which the biasing spring 304 biases the second conveyance guide 303 may also be regarded as the direction in which the positioning projection 303b enters the state in which the positioning projection 303b is positioned by the groove 302 b.

Also, in the present exemplary embodiment, when the second conveying guide 303 moves in the predetermined direction (opposite direction), the engagement between the groove 302b and the positioning protrusion 303b is released, and the positioning of the second conveying guide 303 with respect to the first conveying guide 302 is released. The direction in which the biasing spring 304 biases the second conveyance guide 303 may be regarded as a direction opposite to the predetermined direction.

As shown in fig. 18A, the following three forces act on the second conveyance guide 303: that is, the reaction force of the sheet refeeding roller spring 18c, indicated by the arrow A5-3, which applies a pressing force to the second sheet refeeding roller 18b forming a nip with the first sheet refeeding roller 18a, the biasing force of the biasing spring 304, indicated by the arrow A6, and the gravity, indicated by the arrow A7, due to the self weight of the second conveying guide 303. As shown in fig. 18B, while the positioning protrusion 303B is held in the groove 302B, an arrow C indicating the direction of resultant force acting on the shaft center 303B1 of the positioning protrusion 303B overlaps with the range X.

Thus, the positioning protrusion 303b is firmly positioned by the groove 302 b. In a state where the second conveying guide 303 is positioned relative to the first conveying guide 302 and the positioning protrusion 303b is engaged with the groove 302b, the positioning protrusion 303b is in contact with the contact surfaces 302b1 and 302b2 of the first conveying guide 302. The range X is between a line connecting the point at which the positioning protrusion 303b and the contact surface 302b1 contact each other and the axis 303b1 and a line connecting the point at which the positioning protrusion 303b and the contact surface 302b2 contact each other and the axis 303b 1.

In a state where the second conveying guide 303 is positioned with respect to the first conveying guide 302, two portions (two contact portions) of the positioning protrusion 303b are in contact with a portion (a portion where the groove 302b is formed) of the first conveying guide 302. The reaction force indicated by the arrow A5-3 acts such that the two contact portions of the positioning projection 303b are pressed against a portion of the first conveying guide 302 (a portion forming the groove 302 b). The resultant force indicated by the arrow C acts such that the two contact portions of the positioning projection 303b are pressed against a portion of the first conveying guide 302 (a portion forming the groove 302 b).

Next, an operation of opening the second conveyance guide 303 will be described. The second conveyance guide 303 includes a handle portion 303c, and the handle portion 303c is configured to push the second conveyance guide 303 in a direction indicated by an arrow A2 as shown in fig. 16.

When the second conveying guide 303 is pushed in the direction indicated by the arrow A2, as shown in fig. 19A, the positioning protrusion 303b moves from the contact surface 302b2 of the groove 302b to the upstream side in the conveying direction of the sheet S. At this time, as shown in fig. 19B, the engagement protrusion 303a moves to the upstream side in the long hole 302 a. Then, as shown in fig. 20A, the positioning protrusion 303b of the second conveying guide 303 passes through the first guide end 302b4.

At this time, as shown in fig. 20A, 20B, and 20C, the dead weight of the second conveyance guide 303 indicated by the arrow A7 acts on the second conveyance guide 303 in addition to the operation force indicated by the arrow A8 and the biasing force indicated by the arrow A6. With the resultant of these three forces indicated by the broken-line arrow D, the second conveying guide 303 enters an open state as shown in fig. 21.

Next, an operation of closing the second conveyance guide 303 will be described. When the second conveying guide 303 is lifted in the open state shown in fig. 21, as shown in fig. 22, the engaging protrusion 303a is movable relative to the long hole 302 a. Fig. 22 illustrates the pivot locus L4 of the positioning protrusion 303 b. As shown in fig. 22, the second conveyance guide 303 is lifted in a state where the second conveyance guide 303 is biased downstream in the conveyance direction by the biasing force of the biasing spring 304 indicated by an arrow A6.

At this time, as shown in fig. 23A and 23B, in a state where the engagement protrusion 303A is engaged with the long hole 302a, the positioning protrusion 303B is in contact with the fifth guide portion 302B3 of the groove 302B on the pivot locus L4. Further, as shown in fig. 23A, an operating force indicated by an arrow A9 for raising the second conveying guide 303 acts on the second conveying guide 303, and the second conveying guide 303 is raised along the fifth guide 302b3 against the dead weight indicated by an arrow A7 in the direction indicated by an arrow A3.

Then, as shown in fig. 24A and 24B, in a state where the engagement protrusion 303a is engaged with the long hole 302a, the positioning protrusion 303B of the second conveying guide 303 passes through the first guide end 302B4. At this time, in addition to the operation force indicated by the arrow A9 and the self weight indicated by the arrow A7, the biasing force of the biasing spring 304 indicated by the arrow A6 also acts on the second conveying guide 303, and the positioning projection 303b moves in the resultant force direction indicated by the arrow E in fig. 24C by the biasing force indicated by the arrow A6.

As shown in fig. 24D, the positioning projection 303b moving in the resultant force direction indicated by the arrow E moves along the contact surface 302b1 by the resultant force of the biasing force indicated by the arrow A6 and the self weight indicated by the arrow A7 without the operation force indicated by the arrow A9, and is positioned in the groove 302b by the above resultant force indicated by the arrow C.

As described above, in a state where the engagement protrusion 303a and the long hole 302a are engaged with each other, the second conveyance guide 303 can be moved in a predetermined direction to the positioning position and the release position with respect to the first conveyance guide 302.

As shown in fig. 17, the second conveying guide 303 is positioned relative to the first conveying guide 302 while the second conveying guide 303 is in a positioning position relative to the first conveying guide 302. In this state, the groove 302b and the positioning protrusion 303b are engaged with each other, and the second conveying guide 303 is restricted from pivoting in the opening direction with respect to the first conveying guide 302. In other words, a portion of the first conveying guide 302 is located downstream of a portion of the second conveying guide 303 with respect to the opening direction related to the joint protrusion 303 a.

The first duplex conveying roller 17b and the second duplex conveying roller 17a contact each other to convey the sheet S while the second conveying guide 303 is in a positioning position with respect to the first conveying guide 302. Further, the first conveying guide 302 and the second conveying guide 303 form the conveying path 21.

On the other hand, as shown in fig. 20A and 20B, while the second conveying guide 303 is in the release position with respect to the first conveying guide 302, the engagement protrusion 303a and the long hole 302a are engaged with each other, and the engagement between the groove 302B and the positioning protrusion 303B is released. In this state, the second conveying guide 303 is allowed to pivot in the opening direction with respect to the first conveying guide 302. In a state where the engagement protrusion 303a and the long hole 302a are engaged with each other, the second conveying guide 303 is pivoted in the opening direction from the release position with respect to the first conveying guide 302, thereby opening the conveying path 21.

In a state where the engagement protrusion 303a and the long hole 302a are engaged with each other, when the second conveying guide 303 moves in a predetermined direction with respect to the first conveying guide 302, the engagement between the groove 302b and the positioning protrusion 303b is released. Then, the positioning of the second conveying guide 303 with respect to the first conveying guide 302 is also released. The predetermined direction may be referred to as "a direction from the positioning position to the releasing position". When the second conveying guide 303 moves from the positioning position to the releasing position, the second duplex conveying roller 17a moves relative to the first duplex conveying roller 17b. More specifically, the second duplex conveying roller 17a moves in a direction intersecting the rotation axis direction of the first duplex conveying roller 17b. The second duplex conveying roller 17a is away from the first duplex conveying roller 17b while the second conveying guide 303 is at the release position.

Further, the biasing spring 304 biases the second conveyance guide 303 in a direction from the release position to the positioning position.

As described above, the biasing spring 304 applies the biasing force indicated by the arrow A6 in the direction opposite to the pressing direction, and thus the positioning protrusion 303b can be held in the groove 302b without the operating force indicated by the arrow A9 after the positioning protrusion 303b passes through the first guide end portion 302b 4. The present exemplary embodiment can provide an image forming apparatus including a conveyance guide that simplifies user operations and has excellent usability.

Fig. 25A and 25B are side views illustrating a configuration according to the third exemplary embodiment. Fig. 25A illustrates a state in which the second conveyance guide 403 is closed. Fig. 25B illustrates a state in which the second conveyance guide 403 is open. As shown in fig. 25A and 25B, the second conveyance guide part 403 includes a long hole 403a as a first engaged part and a groove 403B as a second engaged part. The first conveying guide 402 includes an engagement protrusion 402a as a first engagement portion and a positioning protrusion 402b as a second engagement portion.

Alternatively, the first engaging portion may be a first protruding portion, the first engaged portion may be a long hole engaged with the first protruding portion, the second engaged portion may be a second protruding portion, and the second engaging portion may be a groove portion engaged with the second protruding portion. Further, alternatively, the first engaged portion may be a first protruding portion, the first engaging portion may be a long hole engaged with the first protruding portion, the second engaging portion may be a second protruding portion, and the second engaged portion may be a groove portion engaged with the second protruding portion. Instead of the V-shape, the groove portion may have a semicircular shape. The elongated hole may have a groove shape.

In other words, one of the first engaging portion and the first engaged portion may be a protruding portion, and the other may be a long hole engaged with the protruding portion. One of the second engaging portion and the second engaged portion may be a protruding portion, and the other may be a recessed portion engaged with the protruding portion. The same applies to the configuration according to the second exemplary embodiment.

Next, a fourth exemplary embodiment will be described with reference to fig. 26 to 32B. In the present exemplary embodiment, components similar to those described in the first exemplary embodiment are denoted by the same reference numerals. Components and functions similar to those in the first exemplary embodiment will not be described again, and features of the present exemplary embodiment will be mainly described.

Fig. 26 is a cross-sectional view of the image forming apparatus 102 according to the present exemplary embodiment. Fig. 26 illustrates a configuration for opening the transfer unit 501. In addition, in the case where the conveying path of the re-conveying sheet S extends in the up-down direction as shown in fig. 26, the conveying path may be opened as shown in the first to third exemplary embodiments. More specifically, the positioning of the conveying guide can be released by moving the conveying guide in the up-down direction, and the conveying path can be opened by pivoting the conveying guide. As a method of joining the conveyance guide, a method similar to that shown in the first to third exemplary embodiments can be used.

In the present exemplary embodiment, in the conveyance path of the sheet S, the image forming apparatus 102 is different from the image forming apparatus 101 according to the first exemplary embodiment. The image forming apparatus 102 according to the present exemplary embodiment includes the photosensitive drum 2 as a first roller and the transfer roller 8 as a second roller capable of contacting the photosensitive drum 2. The sheet S fed from the sheet feeding cassette 5 by the sheet feeding roller 4 passes through the registration roller pair 7, the transfer unit 501, and the fixing device 9 above the sheet S in the vertical direction, and is discharged to the sheet discharge tray 16 by the sheet discharge roller 13 and the sheet discharge driven roller 14. In this case, the transfer unit 501 is opened and closed to clear a jam or replace the transfer roller 8.

< transfer Unit >

Next, the configuration of the transfer unit 501 in fig. 26 will be described with reference to fig. 27 and 28. Fig. 27 is a schematic cross-sectional view of the transfer unit 501. Fig. 28 is a schematic side view illustrating a mechanism for fastening the second conveying guide 503 provided at each end of the conveying path in the second conveying guide 503. Arrow F1 in fig. 27 indicates the conveying direction of the sheet S.

As shown in fig. 28, an engaging protrusion 503a provided on the upstream side of the second conveying guide portion 503 in the conveying direction is held in a long hole 502a of the first conveying guide portion 502, and a positioning protrusion 503b provided on the downstream side is held in a groove 502 b. In this state, as shown in fig. 27, the positioning projection 503b is positioned in the groove 502b by the reaction force of the transfer roller spring 8a that applies a pressing force to the transfer roller 8, the transfer roller 8 forming a nip with the photosensitive drum 2.

In the image forming apparatus 102 according to the present exemplary embodiment, the main body 103 includes the first conveying guide 502 and the photosensitive drum 2 as the first roller, and the main body 103 does not include the second conveying guide 503 that can be opened and closed. The first conveyance guide 502 is provided in the frame of the main body 103, and a groove 502b and a long hole 502a are provided in the first conveyance guide 502. In other words, the body 103 includes the first conveyance guide 502.

The operation of opening the second conveyance guide 503 will now be described. To open the second conveying guide 503, the door 19 shown in fig. 26 is opened (into a state indicated by a broken line), and a force is applied to the handle portion 503c of the second conveying guide 503 shown in fig. 27 in a direction indicated by an arrow F2. Then, as shown in fig. 29, the positioning projection 503b climbs over the first guide portion 502b1 of the groove 502b and climbs over the first guide portion end 502b6. Then, as shown in fig. 30, the positioning projection 503b moves in the direction indicated by the broken line arrow G, and the second conveyance guide 503 enters the open state.

Next, an operation of closing the second conveyance guide 503 will be described with reference to fig. 31A and 31B. When the second conveyance guide 503 is lifted in the open state, the engagement protrusion 503a is movable relative to the long hole 502a in the conveyance direction of the sheet S. As shown in fig. 31A, when the second conveying guide portion 503 is closed in a state where the engagement protrusion 503a is at the lower end of the long hole 502a, the positioning protrusion 503b is in contact with the fourth guide portion 502b4 on the pivot locus L5.

In this state, when the user presses the second conveyance guide 503 in the direction in which the second conveyance guide 503 is closed (indicated by an arrow F6), the positioning projection 503b moves in the direction indicated by an arrow F3 along the fourth guide 502b4 and contacts the third guide 502b 3.

As shown in fig. 31B, when the second conveying guide portion 503 is closed in a state where the engagement protrusion 503a is at the upper end of the long hole 502a, the positioning protrusion 503B is in contact with the third guide portion 502B3 on the pivot locus L6. In this state, when the user presses the second conveyance guide 503 in the direction in which the second conveyance guide 503 is closed (indicated by an arrow F6), the positioning projection 503b moves along the third guide 502b3 in the direction indicated by an arrow F4. Then, as shown in fig. 32A, the positioning projection 503b reaches the contact surface 502b5 of the groove 502 b.

In the present exemplary embodiment, as shown in fig. 32A, the shaft center 503b1 of the positioning protrusion 503b is configured to be at a position upstream of the first guide portion end 502b6 by L7 in the conveying direction. When the user releases the second conveying guide 503 in this state, the positioning protrusion 503b is positioned in the groove 502 b.

As shown in fig. 32A, when the positioning protrusion 503b is in contact with the contact surface 502b5 of the groove 502b, an arrow F5-2 indicating the direction of the reaction force of the transfer roller 8 acting on the shaft center 503b1 of the positioning protrusion 503b overlaps with the range W. The range W is from a line connecting the shaft center 503b1 of the positioning protrusion 503b and the first guide portion end 502b6 to a line perpendicular to the second guide portion 502b2 through the shaft center 503b1 of the positioning protrusion 503 b.

The configuration according to the present exemplary embodiment can position the second conveyance guide 503 directly with respect to the main body 103. The configuration can also provide an image forming apparatus including a conveyance guide that can be miniaturized inexpensively but has excellent usability and attachment position accuracy.

According to an exemplary embodiment of the present invention, the positioning of the transport guide may be released by moving the transport guide itself. Accordingly, an image forming apparatus having excellent usability can be provided.

While the invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims should be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims (17)

1. An image forming apparatus configured to form an image on a sheet, comprising:

a first conveying guide portion including a first roller, a first engaging portion, and a second engaging portion; and

a second conveying guide portion including a second roller, a first engaged portion configured to engage with the first engaging portion, and a second engaged portion configured to engage with the second engaging portion,

Wherein the first conveying guide and the second conveying guide form a conveying path that conveys the sheet in a state where the second conveying guide is positioned at a predetermined position with respect to the first conveying guide, and the first roller and the second roller contact each other to convey the sheet,

wherein in a state in which the first engaging portion and the first engaged portion are engaged with each other, the second conveying guide portion is configured to move in a predetermined direction with respect to the first conveying guide portion, so that the engagement between the second engaging portion and the second engaged portion is released and the positioning of the second conveying guide portion with respect to the first conveying guide portion is released, and

wherein in a state in which the first engaging portion and the first engaged portion are engaged with each other and the positioning of the second conveying guide portion with respect to the first conveying guide portion is released, the second conveying guide portion is configured to pivot in an opening direction with respect to the first conveying guide portion, thereby opening the conveying path.

2. The image forming apparatus according to claim 1,

wherein the second conveying guide portion is configured to move between a positioning position and a releasing position with respect to the first conveying guide portion with the first engaging portion and the first engaged portion engaged with each other,

Wherein the second conveying guide is positioned relative to the first conveying guide and is restricted from pivoting relative to the first conveying guide in the opening direction while the second conveying guide is at the positioning position, and

wherein the second conveying guide is allowed to pivot in the opening direction with respect to the first conveying guide while the second conveying guide is at the release position.

3. The image forming apparatus according to claim 2, wherein the second roller moves relative to the first roller in a case where the second conveying guide moves from the positioning position to the release position.

4. The image forming apparatus according to claim 2, further comprising a biasing member configured to bias the second conveying guide in a direction from the release position to the positioning position.

5. The image forming apparatus according to claim 1, wherein the second conveyance guide portion includes a pressing portion, and pressing the pressing portion causes the second conveyance guide portion to move in a direction in which the engagement between the second engaged portion and the second engaging portion is released.

6. The image forming apparatus according to claim 1, wherein the second engaging portion is configured to receive a self weight of the second conveying guide portion via the second engaged portion.

7. The image forming apparatus according to claim 1, further comprising a biasing member configured to bias the second conveying guide portion in a direction in which the second engaged portion enters a state of being positioned by the second engaging portion.

8. The image forming apparatus according to claim 1, wherein the first engaged portion is a protruding portion, and the first engaging portion is a long hole engaged with the protruding portion.

9. The image forming apparatus according to claim 1, wherein the first engaged portion is a long hole, and the first engaging portion is a protruding portion configured to engage with the long hole.

10. The image forming apparatus according to claim 1, wherein the second engaged portion or the second engaging portion is a protruding portion.

11. The image forming apparatus according to claim 1, wherein the first conveying guide includes a third roller configured to convey the sheet, and the second conveying guide includes a fourth roller configured to contact the third roller and convey the sheet, and a roller bias configured to bias the fourth roller toward the third roller.

12. The image forming apparatus according to claim 1, wherein the conveying path is a conveying path that conveys a sheet on one face of which an image is formed.

13. The image forming apparatus according to claim 1, wherein the second conveying guide portion pivots in the opening direction with respect to the first conveying guide portion under a self weight of the second conveying guide portion.

14. The image forming apparatus according to claim 1, wherein the first roller and the second roller are away from each other in a state where the second conveying guide is pivoted and the conveying path is opened.

15. The image forming apparatus according to claim 1, wherein moving the second conveyance guide in the predetermined direction causes the first roller and the second roller to separate from each other.

16. The image forming apparatus according to claim 1, further comprising a main body including the first conveyance guide,

wherein the first roller is a photosensitive drum, and the second roller is a transfer roller configured to contact the photosensitive drum.

17. The image forming apparatus according to any one of claims 1 to 16, wherein the predetermined direction is a direction opposite to a conveying direction of the sheet.