JP2021187634A - Medium conveyance apparatus and image formation apparatus - Google Patents

Abstract

To achieve high replacement workability of a roller.SOLUTION: A paper feeding unit 40 includes: a paper feeding sub roller 13 which rotates around a rotational axis along the rotational axis direction (horizontal direction) and conveys a paper sheet P as a medium; movable bearings 66 for retaining the paper feeding sub roller 13 to be rotatable; a spring 68 for generating an energizing force for energizing the paper feeding sub roller 13 in a roller energizing direction Du as a first direction along the rotational axis direction; and a movable lever 44 which engages with the movable bearings 66 and can move in a roller retreat direction De as a second direction opposite to the roller energizing direction Du along with the movable bearings 66. The movable bearings 66 can move in the roller retreat direction De relative to the movable lever 44.SELECTED DRAWING: Figure 15

Description

The present invention relates to a medium transport device and an image forming apparatus, and is suitable for application to an image forming apparatus provided with rollers that can be attached to and detached from the housing of the image forming apparatus by feeding out paper from a paper cassette accommodating the paper.

In the conventional image forming apparatus, a feeding device for conveying the paper from the paper cassette for accommodating the paper used for printing toward the image forming portion is provided. Such a paper feed device includes a paper feed sub-roller that comes into contact with the uppermost surface of the paper stored in the paper cassette and transports the paper to the downstream side in the transport direction, and a separation roller adjacent to the paper feed sub-roller on the downstream side in the transport direction. It has a paper feed roller that separates and conveys a plurality of sheets of paper that are stacked and conveyed from the paper feed sub-roller by sandwiching the paper between them. These two rollers have a structure in which at least the surface layer is made of a member having a high coefficient of friction such as rubber, and the transport performance deteriorates with time due to wear, so that the two rollers can be easily replaced (for example,). , Patent Document 1).

Japanese Unexamined Patent Publication No. 2016-98055

However, in the conventional image forming apparatus, when replacing at least one of the paper feed roller and the paper feed sub roller, it may be difficult to remove and attach the rollers.

The present invention has been made in consideration of the above points, and an object of the present invention is to propose a medium transfer device and an image forming device that can improve the roller replacement workability.

In order to solve this problem, in the medium transfer device of the present invention, a first roller member that rotates about a rotation axis and conveys the medium, and a first holding portion that rotatably holds the first roller member. And, the first urging member that generates an urging force that urges the first roller member in the first direction along the rotation axis direction and the first holding portion are engaged with the first holding portion together with the first holding portion. A movable portion that can move in the second direction opposite to the first direction is provided, and the first holding portion can move in the second direction with respect to the movable portion.

Further, in the image forming apparatus of the present invention, the above-mentioned medium transporting device and a housing having a housing opening for accommodating the medium transporting device and exposing at least a part of the medium transporting device to the outside are provided. did.

Thereby, in the present invention, even if the movable portion is not operated, when the first roller member comes into contact with the first holding portion, the first roller member is retracted in the second direction while the first holding portion is retracted in the second direction. Can be easily attached to the frame.

According to the present invention, it is an object of the present invention to propose a medium transfer device and an image forming device that can improve the roller replacement workability.

It is a left side view which shows the structure of an image forming apparatus. It is a perspective view which shows the structure of the paper feed unit in the state where a roller is attached. The configuration of the paper feed unit around the paper feed roller in the state where the paper feed roller is mounted is shown, and is a cross-sectional view taken along the line AA of the rotation axis of the paper feed roller in FIG. The configuration of the paper feed unit around the paper feed sub-roller in the state of mounting the paper feed sub-roller is shown, and is a cross-sectional view taken along the line BB of the rotation axis of the paper feed sub-roller in FIG. It is a bottom view which shows the structure (1) of a paper feed roller and a paper feed sub-roller in a state where a roller is attached. It is a perspective view which shows the structure (2) of a paper feed roller and a paper feed sub-roller in a state where a roller is attached. It is a perspective view which shows the structure of a movable lever. It is a perspective view which shows the structure of a movable bearing. The configuration of the movable lever and the movable bearing in the state where the spring is mounted is shown, and is a cross-sectional view taken along the line CC in FIG. FIG. 6 is a cross-sectional view taken along the line CC in FIG. 6 showing the configurations of a movable lever, a movable bearing, and a spring in a state of being mounted on a paper feed frame. It is a perspective view which shows the method of removing a paper feed roller and a paper feed sub-roller. The configuration of the paper feed unit around the paper feed roller in the detachable state of the paper feed roller is shown, and is a cross-sectional view taken along the line AA of the rotation axis of the paper feed roller in FIG. The configuration of the paper feed unit around the paper feed sub-roller in the detachable state of the paper feed sub-roller is shown, and is a cross-sectional view taken along the line BB of the rotation axis of the paper feed sub-roller in FIG. A method (1) for attaching the paper feed sub-roller is shown, and is a cross-sectional view taken along the line BB on the rotation axis of the paper feed sub-roller in FIG. FIG. 2 shows a method (2) for attaching a paper feed sub-roller, and is a cross-sectional view taken along the line BB on the rotation axis of the paper feed sub-roller in FIG. It is a bottom view which shows the structure of the paper feed roller and the paper feed sub-roller by another embodiment.

Hereinafter, embodiments for carrying out the invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

[1. Configuration of image forming device]
As shown in the left side view in FIG. 1, the image forming apparatus 1 is a monochrome electrophotographic printer, for example, on a sheet of paper P having a size such as A3 size or A4 size. On the other hand, a desired monochrome image is printed. In the image forming apparatus 1, various parts are arranged inside the housing 2 formed in a substantially box shape. Incidentally, in the following description, the right end portion on the paper surface in FIG. 1 is defined as the front surface of the image forming apparatus 1, and the vertical direction, the horizontal direction, and the front-rear direction when viewed facing the front surface are defined and described. Further, in the following, regarding the direction in which the paper P is conveyed, the position close to the paper cassette 11 (described later) that is the supply source of the paper P when viewed from an arbitrary position is referred to as the upstream side in the conveying direction, and is a position far from the paper cassette 11. Is called the downstream side in the transport direction. Further, in the following, the direction in which the paper P travels is referred to as a transport direction, and the left-right direction orthogonal to the transport direction and the thickness direction of the paper P is referred to as a transport width direction (rotational axis direction).

The image forming apparatus 1 is located inside the housing 2, for example, an image forming unit 3 that transfers an image to the paper P and an upstream side of the image forming unit 3 in the transport direction, and the paper P is transferred to the image forming unit 3. Is provided with a print medium supply unit 10 for supplying the above.

The print medium supply unit 10 includes a paper cassette 11, a paper feed unit 40, a separation roller 14, a resist roller 17, a pressure roller 18, a feeding sensor 19, and a writing sensor 20. The paper feed unit 40 includes a paper feed roller 12, a paper feed sub-roller (pickup roller) 13, an intermediate transfer roller 15, and a pinch roller 16.

A housing opening 2A is formed in front of the paper feed roller 12 and the paper feed sub-roller 13 on the front side of the housing 2. The housing opening 2A is a long opening in the left-right direction, and communicates the rear and front of the front plate of the housing 2, that is, the internal space surrounded by the housing 2 with the outside. In the image forming apparatus 1, the paper cassette 11 is detachably attached to the housing 2 via the housing opening 2A. The housing opening 2A is closed by the paper cassette 11 when the paper cassette 11 is mounted on the housing 2.

The paper cassette 11 is mounted on the housing 2 at the lower part inside the housing 2, and stores a plurality of papers P in a stacked state. The paper cassette 11 is configured to be movable in the paper cassette insertion / removal direction, which is the front-back direction along the horizontal direction, so that the paper cassette 11 can be attached to and detached from the housing 2.

When the image forming apparatus 1 performs printing processing, the paper cassette 11 is housed inside the housing 2, so that the paper cassette is mounted, and the paper P accumulated in the paper cassette 11 is fed out and the paper P is fed out. Form an image.

On the other hand, the image forming apparatus 1 starts from the paper cassette mounted state during maintenance work such as paper replenishment work in which the paper P is replenished or roller replacement work in which the paper feed roller 12 and the paper feed sub-roller 13 are replaced. When the paper cassette 11 is pulled out from the housing 2 in the front direction of the insertion / removal direction, which is the paper cassette removal direction, the paper cassette 11 is removed from the housing 2 to the outside. .. Subsequently, the image forming apparatus 1 replenishes the paper cassette 11 with paper P, replaces the paper feed roller 12 and the paper feed sub-roller 13, and then changes the paper cassette from the removed state to the rear direction in the paper cassette insertion / removal direction. When the paper cassette 11 is pushed into the housing 2 in the direction of mounting the paper cassette, the paper cassette is mounted. During this roller replacement work, the operator visually observes the movable lever gripping portion 44G (described later) from the front to the rear of the housing opening 2A, and enters the housing 2 from the front to the rear through the housing opening 2A. The paper feed roller 12 or the paper feed sub-roller 13 is replaced by operating the movable lever grip portion 44G by putting a hand in the paper feed roller 12.

The paper feed roller 12, the paper feed sub roller 13, and the separation roller 14 separate the paper P located on the uppermost layer of the plurality of paper P stored in the paper cassette 11 one by one and sequentially take them out, and sequentially take out the intermediate transport roller. It is a paper feed mechanism that feeds toward 15. As a result, the image forming apparatus 1 reliably separates the paper P located on the uppermost layer of the paper cassette 11 from the other paper P located on the lower layer thereof.

The intermediate transfer roller 15 and the pinch roller 16 sandwich the paper P fed from the paper feed roller 12, the paper feed sub-roller 13, and the separation roller 14 in pairs, and transfer the paper P to the downstream side in the transfer direction. The resist roller 17 and the pressure roller 18 sandwich the paper P transported from the intermediate transport roller 15 and the pinch roller 16 in pairs, and transport the paper P to the downstream side in the transport direction while correcting the skew of the paper P. A feeding sensor 19 is provided on the upstream side of the resist roller 17 and the pressure roller 18 in the transport direction. The feeding sensor 19 detects the position of the paper P. A writing sensor 20 is provided on the downstream side of the resist roller 17 and the pressure roller 18 in the transport direction. The writing sensor 20 detects the position of the paper P when the timing for forming the image on the paper P is instructed to the image forming unit 3.

As shown in FIG. 1, the image forming unit 3 has a toner cartridge 21, an image drum 22, an exposure head 23, a transfer roller 24, and a fixing unit 25. For example, using black toner (developer), paper is used. A black image (toner image) is formed on P.

The toner cartridge 21 is a container in which toner of a predetermined color is stored. That is, in the example of the image forming unit 3, the black toner is housed in the toner cartridge 21.

The image drum 22 is a member that supports an electrostatic latent image on the surface, and is configured by using a photoconductor (for example, an organic photoconductor). The image drum 22 rotates at a predetermined peripheral speed, and for example, black toner is supplied from the toner cartridge 21. Therefore, a black image (toner image) in which black toner is attached to the electrostatic latent image is formed on the image drum 22.

The exposure head 23 includes, for example, a light source such as a plurality of light emitting diodes (LEDs) and laser elements that emit irradiation light, and a lens array that forms an image of the irradiation light on the surface of the image drum 22. ing. The exposure head 23 forms an electrostatic latent image on the surface of the image drum 22 by irradiating the surface of the image drum 22 with irradiation light to expose the surface of the image drum 22.

The transfer roller 24 is made of, for example, a foamable semi-conductive elastic rubber material. The transfer roller 24 is arranged to face the image drum 22, and electrostatically transfers, for example, a black image (toner image) formed by the image drum 22 onto the paper P.

The fixing unit 25 fixes the toner image on the paper P by applying heat and pressure to the toner (toner image) on the paper P conveyed from the transfer roller 24. The fixing unit 25 includes a heat roller 26 and a pressure roller 27. The heat roller 26 includes a heater 26A such as a halogen lamp inside, and applies heat to the toner on the paper P. The pressure roller 27 is arranged so as to form a pressure contact portion with the heat roller 26, and applies pressure to the toner on the paper P.

The image forming apparatus 1 further includes a discharge sensor 28, discharge rollers 29 and 30, pinch rollers 31 and 32, and a discharge tray 33 on the downstream side of the image forming unit 3 in the transport direction.

The ejection sensor 28 detects the paper P ejected from the fixing unit 25. The discharge rollers 29 and 30 are arranged to face the pinch rollers 31 and 32, respectively, hold the paper P on which the toner is fixed by the fixing unit 25, and discharge the paper P to the discharge tray 33 outside the image forming apparatus 1.

[2. Operation of image forming device]
In such a configuration, when the image forming apparatus 1 transfers the toner image to the paper P, first, the paper P stored in the paper cassette 11 is picked up one by one from the top by the paper feed subroller 13 and conveyed. It is fed in the direction of the paper feed roller 12 on the downstream side in the direction. Next, the image forming apparatus 1 conveys the paper P unwound from the paper feed sub-roller 13 by the paper feed roller 12 and the separation roller 14 and directs the paper P to the intermediate transfer roller 15 and the pinch roller 16. Next, the image forming apparatus 1 causes the paper P to reach the resist roller 17 and the pressure roller 18 via the intermediate transfer roller 15 and the pinch roller 16, and then corrects the skew by the resist roller 17 and the pressure roller 18. At the same time, the paper P is conveyed to the image forming unit 3 on the downstream side in the conveying direction.

The image forming unit 3 uniformly charges the surface of the image drum 22 by a charging roller (not shown) to which a predetermined applied voltage is supplied. Next, the image forming unit 3 irradiates the surface of the image drum 22 with irradiation light from the exposure head 23 to expose the surface, thereby forming an electrostatic latent image corresponding to the print pattern on the image drum 22. Next, the image forming unit 3 attaches toner to the electrostatic latent image on the image drum 22 from a developing roller (not shown). Next, the image forming unit 3 transfers the toner (toner image) on the image drum 22 onto the paper P by the electric field between the image drum 22 and the transfer roller 24. By such an electrophotographic process, the image forming unit 3 forms a black toner image on the paper P.

After that, the image forming apparatus 1 applies heat and pressure to the paper P in the fixing unit 25 to fix the toner (toner image) on the paper P to the paper P. Subsequently, the image forming apparatus 1 discharges the paper P on which the toner is fixed to the discharge tray 33 by the discharge rollers 29 and 30 and the like.

[3. Paper feed unit configuration]
As shown in FIG. 2, the paper feed unit 40 includes a paper feed roller 12 and a paper feed roller 12 arranged adjacent to each other in the front-rear direction on the paper feed frame 42 inside the paper feed unit exterior portion 39 forming the exterior. The sub-roller 13 and the paper feed shaft 41 and the like are supported. The paper feed roller 12 and the paper feed sub-roller 13 are arranged one by one at a substantially central portion in the transport width direction of the paper to be transported P.

[3-1. Configuration around the paper feed roller]
As shown in FIGS. 2 and 3, the paper feed shaft 41 is, for example, a metal cylindrical member, and extends along the scanning direction (rotational axis direction). The paper feed shaft 41 is rotatably supported by a pair of bearings 46 and 47 attached to a paper feed frame 42 erected on the paper feed unit 40.

A gear 48 and a coupling 49 are fixed to the left end of the paper feed shaft 41. A motor (not shown) is directly or indirectly connected to the right end of the paper feed shaft 41. The paper feed shaft 41 supports the paper feed roller 12 by being fitted into the paper feed roller 12. Further, the coupling 49 has a built-in one-way clutch and is fitted into the paper feed roller 12 to transmit a driving force to the paper feed roller 12. Therefore, the paper feed roller 12 rotates in the direction of arrow R1 (FIG. 2) together with the paper feed shaft 41 and the gear 48 by the driving force from the motor.

The paper feed roller 12 as the second roller member sandwiches the paper P picked up from the paper cassette 11 one by one with the separation roller 14 (FIG. 1) by the rotation of the paper feed sub roller 13, and the arrow. By rotating in the direction of R1, the paper P is fed downstream in the transport direction. The paper feed roller 12 is composed of a paper feed roller shaft portion 54 and a paper feed roller rubber 56.

The paper feed roller shaft portion 54 is made of, for example, resin, and is fitted with a cylindrical hole along the rotation axis direction from the right end portion to the substantially central portion of the paper feed roller shaft portion 54 in the rotation axis direction at the rotation center portion. It is a substantially cylindrical member on which the portion 54M is formed. Further, the paper feed roller shaft portion 54 has a cylindrical paper feed roller boss portion 54B having a diameter smaller than the diameter of the paper feed roller shaft portion 54 from the rotation center portion of the left end surface in the left direction along the rotation axis direction. Protruding to. The paper feed roller shaft portion 54 is formed with a paper feed roller rubber holding portion 54K that holds the paper feed roller rubber 56 on the outer peripheral surface. Further, on both outer sides of the paper feed roller shaft portion 54 in the rotation axis direction with respect to the paper feed roller rubber holding portion 54K, the outer diameter is larger than the inner diameter of the paper feed roller rubber 56, and the paper feed roller rubber 56 moves in the rotation axis direction. A paper feed roller shaft flange 54F is formed to regulate.

The paper feed roller rubber 56 is formed of an elastic material such as synthetic rubber, and is formed around the paper feed roller shaft portion 54, between the left and right paper feed roller shaft portion flanges 54F in the rotation axis direction, that is, the paper feed roller rubber holding. The portion 54K is continuously covered in the rotation direction.

The paper feed roller shaft portion 54 has a paper feed shaft at the right end of the fitting portion 54M in the paper feed roller mounted state (FIGS. 2, 3 and 5) in which the paper feed roller 12 is mounted on the image forming apparatus 1. When the 41 is fitted and fixed, the right end portion is supported by the paper feed shaft 41, and the rotation of the paper feed shaft 41 is transmitted by the coupling 49. Further, in the paper feed roller shaft portion 54, when the paper feed roller is mounted, the paper feed roller boss portion 54B is fitted into the paper feed roller fitting hole 50A which is a cylindrical recess formed in the movable bearing 50 (described later). By inserting it, the left end portion is rotatably supported by the movable bearing 50. As described above, the paper feed roller shaft portion 54 is supported at both ends in the rotation axis direction by the paper feed shaft 41 and the movable bearing 50 in the state where the paper feed roller is mounted.

The movable bearing 50 as the second holding portion is a bearing, and is located coaxially with the paper feed shaft 41 on the opposite side of the paper feed shaft 41 with the paper feed roller 12 interposed therebetween in the direction of the rotation axis. The movable bearing 50 is moved along the rotation axis direction in the roller urging direction Du (right direction) and the roller retracting direction De (left direction) (FIG. 6) by the movable lever 44 fixed to the paper feed frame 42. It is supported as much as possible. Further, the left inner wall surface 50ASl (FIG. 8) of the paper feed roller fitting hole with the normal line of the paper feed roller fitting hole 50A of the movable bearing 50 directed to the right is in contact with the left end surface of the paper feed roller boss portion 54B. ..

A spring 52 as a second urging member, which is a compression spring, is between the movable bearing 50 and the cylindrical spring support boss portion 42A formed on the paper feed frame 42 facing the left side of the movable bearing 50. However, it is installed in a more compressed state than in the normal state. Therefore, the movable bearing 50 is urged toward the roller urging direction Du, which is the right direction, by the urging force of the spring 52.

In this way, the paper feed roller 12 is pressed against the roller urging direction Du by the urging force of the spring 52 via the movable bearing 50, is formed on the paper feed frame 42, and is a planar positioning portion having a normal line directed to the left. By pressing the right end surface of the right paper feed roller shaft portion flange 54F against the roller support surface 42B, the position in the rotation axis direction is maintained.

The movable lever 44 is formed with a movable lever grip portion 44G (described later) (FIG. 2), which is a lever protruding downward from the paper feed unit exterior portion 39 through a hole formed in the paper feed unit exterior portion 39. ing. When the movable lever grip portion 44G of the movable lever 44 is moved by the operator toward the roller retracting direction De in the direction opposite to the roller urging direction Du against the urging force of the spring 52 and the spring 68 (described later). The movable bearing 50 is pushed by the movable lever 44 and moves together with the movable lever 44 in the roller retracting direction De. As a result, the movable bearing 50 is separated from the paper feed roller shaft portion 54 of the paper feed roller 12 to the left side, and the paper feed roller shaft portion 54 is not urged in the roller urging direction Du.

[3-2. Configuration around the paper feed sub-roller]
As shown in FIGS. 2, 4 and 5, the paper feed sub-roller 13 picks up the paper P from the paper cassette 11 one by one by rotating in the direction of the arrow R2, and receives the paper P to the paper feed roller 12. hand over. The surface of the paper feed sub-roller rubber 62 in the paper feed sub-roller 13 is in contact with the upper surface of one sheet of paper P located on the uppermost layer among the plurality of paper P stored in the paper cassette 11. The paper feed sub-roller 13 is composed of a paper feed sub-roller shaft portion 60 and a paper feed sub-roller rubber 62.

The paper feed sub-roller shaft 60 is made of, for example, resin, and a cylindrical paper feed sub-roller shaft 60S along the rotation axis direction is formed at the center of rotation. The left end of the paper feed sub-roller shaft 60S is a paper feed sub-roller shaft shaft one end 60S1, and the right end is a paper feed sub-roller shaft shaft other end 60S2.

The paper feed sub-roller shaft portion 60 is formed with a paper feed sub-roller rubber holding portion 60K that holds the paper feed sub-roller rubber 62 on the outer peripheral surface. Further, the outer diameter of the paper feed sub-roller shaft 60 is larger than the inner diameter of the paper feed sub-roller rubber 62 on both outer sides in the rotation axis direction with respect to the paper feed sub-roller rubber holding portion 60K, so that the paper feed sub-roller rubber 62 can move in the rotation axis direction. A paper feed sub-roller shaft flange 60F is formed to regulate.

Further, a paper feed sub-roller shaft gear 60G is formed between the paper feed sub-roller shaft portion flange 60F on the right side of the paper feed sub-roller shaft portion 60 and the paper feed sub-roller shaft portion other end 60S2. The paper feed sub-roller shaft gear 60G meshes with the gear 48 of the paper feed shaft 41 via the idle gear 70 (FIG. 2). Therefore, the driving force of the motor is transmitted to the paper feed sub-roller shaft gear 60G via the paper feed shaft 41, the gear 48, and the idle gear 70. As a result, the paper feed roller 12 and the paper feed sub roller 13 rotate in the same direction in synchronization with each other. In this way, the paper feed unit 40 transmits the driving force for rotating the paper feed roller 12 to the paper feed sub roller 13 only on the right side, which is one direction side in the rotation axis direction with respect to the paper feed roller 12 and the paper feed sub roller 13. I made it.

The paper feed sub-roller rubber 62 is formed of an elastic material such as synthetic rubber, and is formed around the paper feed sub-roller shaft portion 60, between the left and right paper feed sub-roller shaft portion flanges 60F in the rotation axis direction, that is, the paper feed sub-roller rubber holding portion 60K. Is continuously covered in the rotation direction, and its outer peripheral surface is in contact with the paper P stored in the paper cassette 11.

In the paper feed sub-roller shaft portion 60, when the paper feed sub-roller 13 is mounted on the image forming apparatus 1 and the paper feed sub-roller shaft 60S is mounted, the paper feed sub-roller shaft shaft other end 60S2 of the paper feed sub-roller shaft 60S feeds paper. By fitting into the paper feed sub-roller other end fitting hole 42F, which is a cylindrical recess formed in the frame 42, the right end portion is rotatably supported by the paper feed sub-roller other end fitting hole 42F. Further, in the paper feed sub-roller shaft portion 60, the paper feed sub-roller shaft portion 60S1 of the paper feed sub-roller shaft portion shaft 60S is a cylindrical recess formed in the movable bearing 66 when the paper feed sub-roller shaft portion 60 is mounted. By fitting into the fitting hole 66A at one end of the subroller, the left end is rotatably supported by the movable bearing 66. As described above, the paper feed sub-roller shaft portion 60 is supported at both ends in the rotation axis direction by the paper feed sub-roller other end fitting hole 42F and the movable bearing 66 in the paper feed sub-roller mounted state. Hereinafter, the paper feed roller mounted state and the paper feed sub roller mounted state are collectively referred to as a roller mounted state.

The movable bearing 66 is a bearing, and is located coaxially with the paper feed sub-roller other end fitting hole 42F on the opposite side of the paper feed sub-roller other end fitting hole 42F with the paper feed sub-roller 13 sandwiched in the rotation axis direction. ing. The movable bearing 66 is supported by a movable lever 44 fixed to the paper feed frame 42 so as to be movable along the rotation axis direction in the roller urging direction Du and the roller retracting direction De. Further, the left side surface 66ASl (FIG. 8) of the fitting hole at one end of the feeding subroller whose normal line at the fitting hole 66A at one end of the feeding subroller of the movable bearing 66 is directed to the right is the one end 60S1 of the shaft of the feeding subroller shaft. It is in contact with the left end surface.

A spring 68, which is a compression spring, is compressed more than in a normal state between the movable bearing 66 and the cylindrical spring support boss portion 42D formed on the paper feed frame 42 facing the left side of the movable bearing 66. It is installed in a state of being. Therefore, the movable bearing 66 is urged toward the roller urging direction Du, which is the right direction, by the urging force of the spring 68.

In this way, the paper feed sub-roller 13 is pressed against the roller urging direction Du by the urging force of the spring 68 via the movable bearing 66, and the roller support surface with which the paper feed roller shaft flange 54F of the paper feed roller 12 is in contact. The position in the rotation axis direction is maintained by pressing the right end surface of the right paper feed sub-roller shaft portion flange 60F against the roller support surface 42B which is the same surface as the 42B.

When the movable lever grip portion 44G of the movable lever 44 is moved toward the roller retracting direction De against the urging force of the springs 52 and 68 by the operator, the movable bearing 66 is pushed by the movable lever 44 together with the movable bearing 50. And move toward the roller retracting direction De together with the movable lever 44. As a result, the movable bearing 66 is separated from the paper feed sub-roller shaft 60S of the paper feed sub-roller 13 to the left side, and the paper feed sub-roller shaft 60 is not urged in the roller urging direction Du.

In this way, the paper feed unit 40 urges the paper feed roller 12 toward the roller urging direction Du by the spring 52, and the paper feed sub-roller 13 toward the roller urging direction Du by the spring 68, respectively. did. That is, the paper feed unit 40 urges the paper feed roller 12 and the paper feed sub-roller 13 in the same direction with respect to the rotation axis direction.

Further, the paper feed unit 40 has a movable bearing 50 that rotatably holds the paper feed roller 12 and a movable bearing 66 that rotatably holds the paper feed sub roller 13 on the left side of the paper feed sub roller 13 and the paper feed roller 12. I tried to arrange it. That is, in the paper feed unit 40, the movable bearing 50 and the movable bearing 66 are arranged on the same side with respect to the paper feed roller 12 and the paper feed sub-roller 13 in the rotation axis direction.

[3-3. Movable lever configuration]
As shown in FIG. 6, the movable lever 44 has a predetermined thickness in the left-right direction as a whole, and has a shape in which the capital letter "E" is rotated by 90 [°] when viewed from the left side. The movable lever 44 is formed with a movable lever grip portion 44G as a grip portion having a rectangular parallelepiped shape protruding downward at the central portion in the front-rear direction. The movable lever grip portion 44G has a shape that is easy for an operator to pick up by hand.

Further, the movable lever 44 has a paper feed roller movable bearing accommodating portion 44Af having a shape in which the lower side is opened so that the uppercase letter "U" is rotated by 180 [°] in the left side view on the front side of the movable lever grip portion 44G. It is formed. The paper feed roller movable bearing accommodating portion 44Af is formed on the front side and the rear side of the movable bearing support wall 44W extending in the vertical direction in which the inner wall surface facing the front-rear direction is formed. Further, in the paper feed roller movable bearing accommodating portion 44Af, a movable bearing accommodating space 44S, which is a space for accommodating the movable bearing 50, is formed between the movable bearing support wall 44W on the front side and the movable bearing support wall 44W on the rear side. There is. On the inner wall surface of the movable bearing support wall 44W, a rectangular parallelepiped movable bearing fitting groove 44R extending in the left-right direction is engraved from the left end surface of the movable bearing support wall 44W to slightly to the left of the right end surface. ing. At the right end of the movable bearing fitting groove 44R, a movable bearing positioning surface 44P is formed as a planar engaging portion with the normal line directed to the left.

Further, in the movable lever 44, a paper feed sub-roller movable bearing accommodating portion 44Ab having substantially the same shape as the paper feed roller movable bearing accommodating portion 44Af is formed on the rear side of the movable lever grip portion 44G. Since the paper feed sub-roller movable bearing accommodating portion 44Ab has substantially the same shape as the paper feed roller movable bearing accommodating portion 44Af, the description thereof will be omitted. Hereinafter, the paper feed roller movable bearing accommodating portion 44Af and the paper feed sub roller movable bearing accommodating portion 44Ab are collectively referred to as a movable bearing accommodating portion 44A.

[3-4. Structure of movable bearing]
As shown in FIG. 8, the movable bearings 50 and 66 have a substantially cylindrical shape having the same thickness as the movable lever 44 in the left-right direction as a whole, and the upper end surface has a planar shape. Although the movable bearings 50 and 66 are attached to the movable lever 44 at different locations, they have substantially the same shape as each other. Therefore, the movable bearing 50 will be described below.

The movable bearing 50 has a movable bearing left side surface 50LS which is a plane whose normal line is directed to the left so as to be flush with the left end surface of the movable lever 44 when attached to the movable lever 44 on the left end surface. It is formed. Further, in the movable bearing 50, a movable bearing right side surface 50RS is formed on the right end surface. The right side surface 50RS of the movable bearing has a parallel surface 50RS1 formed on the upper half and an inclined surface 50RS2 formed on the lower half. The parallel surface 50RS1 is parallel to the left side surface 50LS of the movable bearing, and when the movable bearing 50 is attached to the movable lever 44, the normal is directed to the right so as to be flush with the right end surface of the movable lever 44. It is a flat surface. The inclined surface 50RS2 is a plane in which the lower end portion is inclined to the left side (the left side surface 50LS side of the movable bearing) with respect to the parallel surface 50RS1 so that the thickness of the movable bearing 50 in the left-right direction becomes thinner toward the downward direction. ..

In the movable bearing 50, a spring fixing portion 50S which is a substantially cylindrical recess is formed in the left side surface 50LS of the movable bearing so that the rear end portion of the spring 52 is fitted. Further, in the movable bearing 50, a paper feed roller fitting hole 50A which is a substantially cylindrical recess is formed in the movable bearing right side surface 50RS so that the paper feed roller boss portion 54B of the paper feed roller 12 is fitted. In the following, in the movable bearing 50, the curved surface forming the upper half of the paper feed roller fitting hole 50A is also referred to as the upper inner wall surface 50ASu of the paper feed roller fitting hole, and is below the paper feed roller fitting hole 50A. The curved surface forming the side half is also called the inner wall surface under the paper feed roller fitting hole 50ASd, and the circular flat surface forming the left end of the paper feed roller fitting hole 50A is the left inner wall surface of the paper feed roller fitting hole. Also called 50ASl. The center of the paper feed roller fitting hole 50A is located at substantially the same position as the contact point between the parallel surface 50RS1 and the inclined surface 50RS2 in the vertical direction.

Further, the length of the inner wall surface 50ASu on the paper feed roller fitting hole in the left-right direction is constant at all positions in the vertical direction of the inner wall surface 50ASu on the paper feed roller fitting hole. On the other hand, the length of the inner wall surface 50ASd under the paper feed roller fitting hole in the left-right direction gradually decreases from the upper side to the lower side. Further, the left-right length of the upper inner wall surface 50ASd of the paper feed roller fitting hole is longer than the left-right length of the inner wall surface 50ASd below the paper feed roller fitting hole.

Further, the length in the left-right direction of the upper inner wall surface 50ASu of the paper feed roller fitting hole, that is, the length from the left inner wall surface 50ASl of the paper feed roller fitting hole to the parallel surface 50RS1 of the movable bearing 50 is the paper feed roller boss portion 54B. It is shorter than the length in the left-right direction. Therefore, the left inner wall surface 50ASl of the paper feed roller fitting hole is in contact with the left end surface of the paper feed roller boss portion 54B.

Here, the length at which the paper feed roller fitting hole 50A and the paper feed roller boss portion 54B overlap with respect to the rotation axis direction in a state where the paper feed roller boss portion 54B of the paper feed roller 12 is fitted into the paper feed roller fitting hole 50A. That is, the length at which the paper feed roller fitting hole upper inner wall surface 50ASu and the paper feed roller boss portion 54B overlap is longer in the upper half than in the lower half in the paper feed roller fitting hole 50A. Of the locations where the paper feed roller fitting hole 50A and the paper feed roller boss portion 54B overlap in the rotation axis direction, the length of the longest portion is also referred to as the paper feed roller fitting depth D1. The tip of the paper feed roller boss portion 54B is inserted into the paper feed roller fitting hole 50A by the amount of the paper feed roller fitting depth D1 in the rotation axis direction.

Further, the movable bearing 50 is fitted with a rectangular parallelepiped movable lever extending in the left-right direction from the left end portion of the front side surface and the rear side surface slightly to the left side of the right end surface on the front side surface and the rear side surface along the left-right direction. The protrusion 50C is protruding. At the right end of the movable lever fitting projection 50C as the engaged portion, a planar contact surface 50T with the normal line directed to the right is formed.

Although the movable bearing 50 has been described above, the movable bearing 66 is configured in substantially the same manner as the movable bearing 50 so that the same alphabet as the movable bearing 50 is added to the end of the code of the member corresponding to the movable bearing 50. ing.

Here, in a state where the paper feed sub-roller shaft one end 60S1 of the paper feed sub-roller 13 is fitted in the paper feed sub-roller one end fitting hole 66A, the paper feed sub-roller one end fitting hole 66A and the paper feed are fed in the direction of the rotation axis. The length at which one end of the subroller shaft shaft 60S1 overlaps, that is, the length at which the upper side surface 66ASu of the paper feed subroller one end fitting hole and the paper feed subroller shaft shaft one end 60S1 overlap is the length at which the paper feed subroller one end fits. The upper half of the hole 66A is longer than the lower half. In this way, the length of the longest part where the paper feed sub-roller one end fitting hole 66A and the paper feed sub-roller shaft shaft one end 60S1 overlap in the direction of the rotation axis is also referred to as the paper feed sub-roller fitting depth D2. Call. The tip of the paper feed sub-roller shaft portion shaft one end 60S1 is inserted into the paper feed sub-roller one end fitting hole 66A by the amount of the paper feed sub-roller fitting depth D2 in the rotation axis direction. The paper feed roller fitting depth D1 and the paper feed sub roller fitting depth D2 have the same value.

As shown in FIG. 9, the movable bearing 50 is pushed to the right from the left side of the left side surface of the movable lever 44 so that the movable lever fitting protrusion 50C fits into the movable bearing fitting groove 44R of the movable lever 44. By doing so, it is supported so as to be movable in the left-right direction with respect to the movable lever 44. Further, the movable bearing 50 is urged in the roller urging direction Du by fitting the right end portion of the spring 52 into the spring fixing portion 50S. At this time, the movable bearing 50 is positioned and its position is maintained by pressing the contact surface 50T (FIG. 8) against the movable bearing positioning surface 44P (FIG. 7) of the movable lever 44. Further, the movable bearing 50 rotatably supports the paper feed roller 12 by fitting the paper feed roller boss portion 54B (FIG. 3) of the paper feed roller 12 into the paper feed roller fitting hole 50A (FIG. 8).

On the other hand, the movable bearing 66 is moved to the right from the left side of the left side surface of the movable lever 44 so that the movable lever fitting projection 66C as an engaged portion fits into the movable bearing fitting groove 44R of the movable lever 44. By being pushed, it is movably supported in the left-right direction with respect to the movable lever 44. Further, the movable bearing 66 is urged in the roller urging direction Du by fitting the right end portion of the spring 68 into the spring fixing portion 66S. At this time, the movable bearing 66 is positioned and its position is maintained by pressing the contact surface 66T (FIG. 8) against the movable bearing positioning surface 44P (FIG. 7) of the movable lever 44. Further, in the movable bearing 66, the paper feed sub-roller 13 is fitted by fitting the paper feed sub-roller shaft one end portion 60S1 (FIG. 4) of the paper feed sub-roller 13 into the paper feed sub-roller one end fitting hole 66A (FIG. 8). Supports rotatably.

As shown in FIG. 10, the movable lever 44 is supported by the paper feed frame 42 so as to rest on the bottom of the paper feed frame 42. At this time, the position of the movable lever 44 in the vertical direction is maintained by the guide portions 42C and 42E formed on the paper feed frame 42 coming into contact with the upper end surface. Further, the movable lever 44 is supported by the paper feed frame 42 so as to be movable in the roller retracting direction De opposite to the roller urging direction Du, which is the direction of the urging force of the spring 52 and the spring 68. At this time, the movable lever grip portion 44G projects downward from the paper feed unit exterior portion 39 via the hole formed in the paper feed unit exterior portion 39.

[4. How to replace the paper feed roller and paper feed sub-roller]
Here, a method of replacing the paper feed roller 12 and the paper feed sub-roller 13 in the image forming apparatus 1 will be described. First, the operator turns off the power of the image forming apparatus 1 main body, and then completely pulls out the paper cassette 11 from the housing 2 forward. As a result, the housing opening 2A (FIG. 1) is opened, and the operator can visually recognize the paper feed roller 12 and the paper feed sub-roller 13 from the outside of the housing 2 as shown in FIG.

As shown in FIG. 11, the operator grips the movable lever gripping portion 44G of the movable lever 44 and moves it in the roller retracting direction De from the roller mounted state shown in FIG. Therefore, the movable bearing positioning surface 44P (FIG. 7) of the movable lever 44 pushes the contact surface 50T (FIG. 8) of the movable bearings 50 and 66 in the roller retracting direction De. As a result, as shown in FIG. 12, the movable bearing 50 is separated from the paper feed roller boss portion 54B of the paper feed roller shaft portion 54 in the paper feed roller 12 in the roller retracting direction De, and the paper feed roller 12 is removed from the coupling 49. The paper feed roller can be attached and detached. At the same time, as shown in FIG. 13, the movable bearing 66 separates the paper feed sub-roller shaft 60S of the paper feed sub-roller shaft 60S from one end 60S1 of the paper feed sub-roller shaft shaft 60S1 in the paper feed sub-roller 13 in the roller retracting direction De, and separates the paper feed sub-roller 13. The paper feed sub-roller is removable from the fitting hole 42F at the other end of the paper feed sub-roller. As described above, the paper feed roller fitting depth D1 and the paper feed sub roller fitting depth D2 have the same value. Therefore, when the movable lever 44 moves in the roller retracting direction De and the movable bearings 50 and 66 move in the roller retracting direction De by the same amount, the paper feed unit 40 is in a state where the paper feed roller can be attached and detached at the same timing. The paper sub-roller can be attached and detached. Hereinafter, the paper feed roller detachable state and the paper feed sub roller detachable state are collectively referred to as a roller detachable state.

Subsequently, the operator moves the paper feed roller 12 to the left to separate it from the coupling 49, and then moves the paper feed roller 12 and the paper feed sub-roller 13 downward when the paper feed roller 12 and the paper feed sub-roller 13 are removed from the paper feed frame 42. Remove the roller in the removing direction. Further, the operator moves the paper feed sub-roller 13 to the left to separate it from the fitting hole 42F at the other end of the paper feed sub-roller, and then removes the paper feed sub-roller 13 in the roller removal direction.

Hereinafter, a method of attaching the paper feed sub-roller 13 will be described. Subsequently, the operator puts a new paper feed sub-roller 13 into the other end of the paper feed sub-roller as shown in FIG. 14 in a state where the paper feed sub-roller is detachable and the hand is released from the movable lever grip portion 44G of the movable lever 44. The other end of the paper feed sub-roller is moved from the lower side of the fitting hole 42F toward the roller mounting direction, which is the upward direction in which the paper feed roller 12 and the paper feed sub-roller 13 move when the paper feed roller 12 and the paper feed sub-roller 13 are mounted on the paper feed frame 42. Insert the other end 60S2 of the paper feed sub-roller shaft portion shaft of the paper feed sub-roller 13 into the portion fitting hole 42F. Subsequently, the operator moves the one end portion 60S1 of the paper feed sub-roller shaft portion shaft in the roller mounting direction and brings it into contact with the inclined surface 66RS2 of the movable bearing 66. Further, the operator pushes the paper feed sub-roller 13 in the roller mounting direction with the upper side of the paper feed sub-roller shaft shaft one end 60S1 in contact with the inclined surface 66RS2 of the movable bearing 66. Therefore, as shown in FIG. 15, as the paper feed sub-roller 13 moves in the roller mounting direction, the movable bearing 66 is pushed by the paper feed sub-roller 13 in the roller retract direction De and moves, and the paper feed sub-roller shaft portion One end 60S1 of the shaft fits into the fitting hole 66A at one end of the paper feed subroller of the movable bearing 66. As a result, the paper feed sub-roller 13 is urged toward the roller support surface 42B by the spring 68 via the movable bearing 66 in the roller urging direction Du, and the paper feed sub-roller is in the state of being mounted as shown in FIG.

As described above, the movable bearings 50 and 66 are supported by the movable lever 44 so as to move in the left-right direction with respect to the movable lever 44. Therefore, even if the movable bearing 66 is pushed by the paper feed sub-roller 13 and moves in the roller retracting direction De, the movable lever 44 does not move in the roller retracting direction De together with the movable bearing 66.

Although the procedure for attaching the paper feed sub-roller 13 has been described above, the paper feed roller 12 can also be mounted in the same procedure as the paper feed sub-roller 13. Further, the case where both the paper feed roller 12 and the paper feed sub-roller 13 are replaced has been described. However, when either the paper feed roller 12 or the paper feed sub-roller 13 is replaced, the replacement work of one of the rollers is performed. Only done.

[5. Effect, etc.]
In the above configuration, in the paper feed unit 40, the image forming apparatus 1 presses the paper feed roller 12 toward the roller support surface 42B via the movable bearing 50 by the urging force of the spring 52 and supplies the paper feed roller 12 to the roller urging direction Du. The paper sub-roller 13 is pressed against the roller support surface 42B in the roller urging direction Du by the urging force of the spring 68. Further, the image forming apparatus 1 is provided with a movable lever 44 that engages with the movable bearings 50 and 66 in the paper feed unit 40 and can move together with the movable bearings 50 and 66 in the roller urging direction Du and the roller retracting direction De. The movable bearings 50 and 66 are configured to be movable in the roller retracting direction De with respect to the movable lever 44.

Therefore, in the image forming apparatus 1, the movable lever 44 is simply moved in the roller retracting direction De against the urging force of the springs 52 and 68, and the movable bearing 50 is separated from the paper feed roller 12 from the coupling 49. The movable bearing 66 can be easily removed from the paper feed sub-roller 13 and can be easily removed from the other end fitting hole 42F of the paper feed sub-roller.

Further, in the image forming apparatus 1, the movable bearings 50 and 66 can be moved in the roller retracting direction De with respect to the movable lever 44 without moving the movable lever 44. Therefore, in the image forming apparatus 1, even if the operator does not pick up the movable lever gripping portion 44G and move the movable lever 44 in the roller retracting direction De, the paper feed roller 12 is in a state where the hand is released from the movable lever gripping portion 44G. Can be easily attached to the movable bearing 50 while retracting the movable bearing 50 in the roller retracting direction De by grasping the movable bearing 50 with one hand and contacting the paper feed sub-roller 13 with the movable bearing 66. The movable bearing 66 can be easily attached to the movable bearing 66 while being retracted in the roller retracting direction De. As a result, the image forming apparatus 1 can improve the roller replacement workability and improve the usability.

As described above, the image forming apparatus 1 is in a visually recognizable direction so that the image forming apparatus 1 can be viewed or put in only from the outside of the housing opening 2A formed in front of the paper feeding roller 12 and the paper feeding sub-roller 13. For the paper feed unit 40, which has relatively poor visibility and workability, the paper feed roller 12 and the paper feed sub-roller 13 can be moved to the paper feed frame 42 simply by moving the movable lever 44 in the roller retracting direction De. The paper feed roller 12 and the paper feed sub-roller 13 can be attached to the paper feed frame 42 without moving the movable lever 44 in the roller retracting direction De.

Further, in the movable bearing 50 of the paper feed unit 40, the image forming apparatus 1 moves toward the roller removal direction side of the movable bearing right side surface 50RS facing the paper feed roller 12 and toward the roller removal direction side. The inclined surface 50RS2 is inclined toward the De side, that is, the normal line is directed toward the roller removal direction side from the roller urging direction Du.

Therefore, in the image forming apparatus 1, the paper feed roller 12 is simply pushed in the roller mounting direction in a state where the upper side of the paper feed roller boss portion 54B of the paper feed roller 12 is in contact with the inclined surface 50RS2 of the movable bearing 50. A part of the force applied to the movable bearing 50 from the paper roller 12 toward the roller mounting direction is converted into a force toward the roller retracting direction De, and the movable bearing 50 can be retracted to the roller retracting direction De by the paper feed roller 12. ..

As a result, the image forming apparatus 1 is only pushed in the roller mounting direction with the paper feed roller 12 in contact with the movable bearing 50, even if the movable lever 44 is not operated so as to be pushed toward the roller retracting direction De. The movable bearing 50 can be retracted to the roller retracting direction De by the paper feed roller 12, and the paper feed roller boss portion 54B can be fitted into the paper feed roller fitting hole 50A of the movable bearing 50, improving the roller replacement workability. Can be made to. Although the movable bearing 50 and the paper feed roller 12 have been described above, the same applies to the movable bearing 66 and the paper feed sub roller 13.

Further, the image forming apparatus 1 attaches the movable bearings 50 and 66 to one movable lever 44 so that the contact surfaces 50T of the movable bearings 50 and 66 are brought into contact with the movable bearing positioning surface 44P of the movable lever 44. .. Therefore, in the image forming apparatus 1, only the movable lever 44 is moved toward the roller retracting direction De against the urging force of the springs 52 and 68, and both the movable bearing 50 and the movable bearing 66 are moved in the roller retracting direction De. Both the paper feed roller 12 and the paper feed sub roller 13 can be made removable at the same time. As a result, the image forming apparatus 1 has workability when removing the rollers, as compared with the case where the movable lever for removing the paper feed roller 12 and the movable lever for removing the paper feed sub roller 13 are provided separately from each other. Can be improved.

Further, the image forming apparatus 1 is configured such that the movable bearings 50 and 66 can be moved in the left-right direction with respect to the movable lever 44 independently of each other so that the movable bearing 50 and the movable bearing 66 do not interlock with each other. Therefore, the image forming apparatus 1 can move the movable bearing 50 and the movable bearing 66 in the roller retracting direction De with respect to the movable lever 44 in an independent state without interlocking with each other. As a result, the paper feed unit 40 can be attached to the paper feed roller 12 and the paper feed sub-roller 13 individually, and the interchangeability of the rollers can be improved.

Further, the image forming apparatus 1 presses the paper feed roller 12 and the paper feed sub roller 13 against the roller urging direction Du toward the roller support surface 42B whose positions in the rotation axis direction are the same as each other. As a result, the image forming apparatus 1 can easily align the centers of the paper feed roller 12 and the paper feed sub-roller 13 in the transport width direction, improve the position accuracy, reduce the occurrence of transport defects, and improve the transport performance.

Further, in the conventional paper feed unit, in order to facilitate replacement, the paper feed roller 12 and the paper feed sub-roller 13 have a cantilever support structure in which the paper feed roller 12 and the paper feed sub-roller 13 are supported only from one side in the rotation axis direction. However, in the case of the cantilever support structure, when the paper is transported from the paper cassette, the center in the transport width direction of the roller is deviated from the center in the transport width direction of the paper, causing skewing, or the paper is first aligned with the paper. Even if the paper is transported straight at a position where the center in the transport width direction coincides with the roller, a force that tilts the paper due to the left-right bias of the paper travel resistance received from the paper travel path on the way acts, and the roller follows the force and the shaft. It moves and the positions of the two rollers are misaligned, making it impossible to suppress skewing. Further, when the paper feed roller is cantilevered, the unsupported side swings, so that the contact position with the separation roller is not stable and skewing is likely to occur.

On the other hand, the image forming apparatus 1 has a double-sided support structure in which the paper feed roller 12 is supported on both sides in the rotation axis direction by the movable bearing 50 and the paper feed shaft 41 in the paper feed unit 40, and the paper feed sub-roller 13 is provided. Is supported on both sides in the direction of the rotation axis by the movable bearing 66 and the fitting hole 42F at the other end of the paper feed sub-roller. Therefore, the image forming apparatus 1 has the two rollers having a double-sided support structure, so that the paper can be conveyed perpendicularly to the rotation axis direction, that is, without skewing, without tilting the rotation axis of the rollers.

Further, in the image forming apparatus 1, in the paper feeding unit 40, the paper feeding roller 12 is pressed against the roller supporting surface 42B of the paper feeding frame 42 toward the roller urging direction Du by the urging force of the spring 52, and the paper feeding sub-roller 13 is pressed. The urging force of the spring 68 presses the paper feed frame 42 toward the roller support surface 42B in the roller urging direction Du.

In this way, the image forming apparatus 1 has a structure in which a common paper feed frame 42 to which two rollers are mounted by using a spring receives an urging force in the same direction, whereby the paper feed roller 12 and the paper feed sub-roller 13 have a structure. By eliminating the shaft shake that is a rattling in the rotation axis direction, it is easy to align the centers of the paper feed roller 12 and the paper feed sub-roller 13 in the transport width direction, it is possible to prevent the occurrence of transport defects, and the transport performance can be improved.

In this way, the image forming apparatus 1 urges each of the paper feed roller 12 and the paper feed sub-roller 13 from one side in the rotation axis direction toward the other side to abut against the paper feed frame 42, thereby positioning the rollers with accuracy. By providing a double-sided support structure for each of the paper feed roller 12 and the paper feed sub-roller 13, it is possible to reduce the occurrence of skewing of the paper.

In this way, the image forming apparatus 1 makes it possible to easily replace each of the paper feed roller 12 and the paper feed sub-roller 13 while maintaining the transport performance so that the paper is stably transported without skewing, and the replacement workability is improved. Can be improved.

According to the above configuration, the paper feed unit 40 rotates about a rotation axis along the rotation axis direction (left-right direction), and can rotate the paper feed sub-roller 13 for transporting the paper P as a medium and the paper feed sub-roller 13. The movable bearing 66 is engaged with the movable bearing 66, the spring 68 that generates an urging force that urges the feed feed sub-roller 13 in the roller urging direction Du as the first direction along the rotation axis direction, and the movable bearing 66. A movable lever 44 is provided together with the movable bearing 66 in a roller retracting direction De as a second direction opposite to the roller urging direction Du, and the movable bearing 66 is provided with a roller retracting direction De with respect to the movable lever 44. Made it movable to.

Further, the image forming apparatus 1 accommodates the paper feeding unit 40 and the paper feeding unit 40, and is formed in front of the paper feeding unit 40 in a direction orthogonal to the rotation axis direction, and at least a part of the paper feeding unit 40 is externally formed. A housing 2 having a housing opening 2A exposed to the surface is provided.

As a result, the image forming apparatus 1 moves the paper feed roller 12 to the paper feed frame while retracting the movable bearing 50 in the roller retracting direction De when the paper feed roller 12 comes into contact with the movable bearing 50 even if the movable lever 44 is not operated. It can be easily attached to 42. At the same time, even if the movable lever 44 is not operated, the image forming apparatus 1 retracts the movable bearing 66 in the roller retracting direction De when the paper feed sub-roller 13 comes into contact with the movable bearing 66, and feeds the paper feed sub-roller 13 to the paper feed frame. It can be easily attached to 42.

[6. Other embodiments]
In the above-described embodiment, the paper feed shaft 41 is inserted into the fitting portion 54M to support the right end portion of the paper feed roller 12 by the paper feed shaft 41, and the paper feed roller boss portion 54B is supplied to the movable bearing 50. The case where the left end portion of the paper feed roller 12 is supported by the movable bearing 50 by fitting the paper roller fitting hole 50A into the paper roller fitting hole 50A has been described. The present invention is not limited to this, and as shown in FIG. 16 in which the members corresponding to those in FIG. 5 are designated by the same reference numerals, the left end portion of the paper feed roller 12 is replaced with the paper feed roller boss portion 54B to be a fitting portion 54M. By inserting a movable shaft 72 as a first holding portion that can move in the rotation axis direction in place of the movable bearing 50 in the fitting portion 54M, the left end portion of the paper feed roller 12 is supported by the movable shaft 72. Is also good. In this case, the image forming apparatus 1 can make the appearances of the paper feed roller 12 and the paper feed sub-roller 13 clearly different, so that the operator can easily distinguish between the paper feed roller 12 and the paper feed sub-roller 13. , The replacement workability can be improved.

Further, on the outer peripheral portion of the movable shaft 72 at the end on the Du side in the roller urging direction, a normal line is provided along the entire circumference along the circumferential direction in the radial direction of the movable shaft 72 rather than the roller urging direction Du. An inclined surface 72S facing to the side is formed.

Therefore, in the image forming apparatus 1, the paper feed roller 12 is simply pushed in the roller mounting direction in a state where the upper side of the paper feed roller 12 is in contact with the inclined surface 72S of the movable shaft 72, and the paper feed roller 12 is mounted on the roller from the paper feed roller 12. A part of the force applied to the movable shaft 72 in the direction can be converted into a force toward the roller retracting direction De, and the movable shaft 72 can be retracted to the roller retracting direction De by the paper feed roller 12.

As a result, in the image forming apparatus 1, even if the movable lever 44 is not operated, the movable shaft 72 is simply pushed in the roller mounting direction with the paper feed roller 12 in contact with the movable shaft 72, and the movable shaft 72 is rolled by the paper feed roller 12. The fitting portion 54M can be fitted to the movable shaft 72 by retracting in the retracting direction De, and the roller replacement workability can be improved.

Further, in the above-described embodiment, when the paper feed roller fitting depth D1 and the paper feed sub-roller fitting depth D2 are set to the same value, the movable lever 44 is moved in the roller retracting direction De. The case where the paper feed roller can be attached and detached and the paper feed sub roller can be attached and detached at the same timing has been described. The present invention is not limited to this, and is different when the movable lever 44 is moved in the roller retracting direction De by setting the paper feed roller fitting depth D1 and the paper feed sub-roller fitting depth D2 to different values. The paper feed roller may be detachable and the paper feed sub roller may be detachable at the timing. Further, when the movable shaft 72 is used instead of the movable bearing 50 as described above, the amount of the movable shaft 72 that enters the fitting portion 54M of the paper feed roller 12 in the rotation axis direction is adjusted to fit the paper feed sub roller of the paper feed sub roller 13. The value may be different from the joint depth D2. In that case, the operator can remove the paper feed roller 12 and the paper feed sub roller 13 one by one at different timings. Further, in that case, of the paper feed roller 12 and the paper feed sub roller 13, the roller whose transport performance tends to deteriorate due to aging is first moved to the roller retracting direction De when the movable lever 44 is moved. The rollers may be made removable so that they can be replaced preferentially.

Further, the movable lever fitting protrusion 50C of the movable bearing 50 and the movable lever fitting protrusion 66C of the movable bearing 66 have different lengths in the left-right direction, and the left side surfaces 50LS and 66LS of the movable bearing are the movable lever 44. By attaching the movable bearings 50 and 66 to the movable lever 44 so as to be flush with the left side surface of the above, the paper feed roller 12 and the paper feed sub-roller 13 may be detachable one by one at different timings.

Further, the lengths of the movable lever fitting protrusion 50C of the movable bearing 50 and the movable lever fitting protrusion 66C of the movable bearing 66 in the left-right direction are shortened by the same length as each other, and the feed roller movable bearing accommodating portion in the movable lever 44 is provided. The distances from the right side surface of the movable lever 44 to the movable bearing positioning surface 44P of the 44Af and the feed subroller movable bearing accommodating portion 44Ab are different from each other, and then the left side surfaces of the movable bearing 50LS and 66LS are on the left side of the movable lever 44. By attaching the movable bearings 50 and 66 to the movable lever 44 so as to be flush with each other, the paper feed roller 12 and the paper feed sub-roller 13 may be detachable one by one at different timings.

Further, in the above-described embodiment, the case where the movable lever grip portion 44G is integrally formed with the movable lever 44 has been described. The present invention is not limited to this, and the movable lever gripping portion 44G may at least be able to move the movable lever 44 in conjunction with the movable lever gripping portion 44G when the movable lever gripping portion 44G is operated.

Further, in the above-described embodiment, the case where both the movable bearing 50 and the movable bearing 66 are moved in the roller retracting direction De by the movable lever 44 moved in the roller retracting direction De has been described. The present invention is not limited to this, and two movable levers may be provided, one is a movable lever that moves the movable bearing 50 in the roller retracting direction De, and the other is a movable lever that moves the movable bearing 66 in the roller retracting direction De.

Further, in the above-described embodiment, the case where both the movable bearing 50 and the movable bearing 66 can move in the roller retracting direction De with respect to the movable lever 44 has been described. The present invention is not limited to this, and either the movable bearing 50 or the movable bearing 66 is fixed to the movable lever 44, and the movable lever 44 may be immovable in the roller retracting direction De.

Further, in the above-described embodiment, the case where the contact surface 50T of the movable bearing 50 abuts on the movable bearing positioning surface 44P of the movable lever 44 in the state where the paper feed roller is mounted has been described. The present invention is not limited to this, and the contact surface 50T may come into contact with the movable bearing positioning surface 44P when the movable bearing 50 is moved in the roller retracting direction De from the state in which the paper feed roller is mounted. The same applies to the paper feed sub-roller.

Further, in the above-described embodiment, the case where the present invention is applied to the paper feed unit 40 having two rollers, the paper feed roller 12 and the paper feed sub-roller 13, has been described. The present invention is not limited to this, and the present invention may be applied to a paper feed unit 40 having one roller of either the paper feed roller 12 or the paper feed sub-roller 13.

Further, in the above-described embodiment, the case where the movable bearing 51 and the movable bearing 66 are arranged on the left side of the paper feed roller 12 and the paper feed sub roller 13 has been described. The present invention is not limited to this, and the movable bearing 51 and the movable bearing 66 may be arranged on opposite sides of the paper feed roller 12 and the paper feed sub roller 13 in the direction of the rotation axis.

Further, in the above-described embodiment, the case where the paper feed roller 12 and the paper feed sub-roller 13 are urged to the right, which is the same direction as the rotation axis direction, has been described. The present invention is not limited to this, and the paper feed roller 12 and the paper feed sub roller 13 may be urged in opposite directions with respect to the rotation axis direction. In that case, a movable lever that makes the paper feed roller 12 detachable and a movable lever that makes the paper feed sub roller 13 detachable may be provided separately.

Further, in the above-described embodiment, the case where the driving force of the motor is transmitted from the paper feed shaft 41 to the paper feed sub-roller shaft gear 60G by the idle gear 70 to rotate the paper feed sub-roller 13. The present invention is not limited to this, and the driving force of the motor may be transmitted from the paper feed shaft 41 to the paper feed subroller 13 by a drive transmission mechanism including various other mechanisms.

Further, in the above-described embodiment, a case where one paper feed roller 12 and a paper feed sub-roller 13 are arranged at a substantially central portion in the transport width direction of the paper to be conveyed P has been described. The present invention is not limited to this, and a plurality of paper feed rollers 12 and paper feed sub rollers 13 may be arranged at intervals shorter than the length in the transport width direction.

Further, in the above-described embodiment, the case where the present invention is applied to the print medium supply unit 10 of the image forming apparatus 1 for forming an image on paper has been described. The present invention is not limited to this, and the present invention may be applied to, for example, a feeder of a device for attaching a label without forming an image on paper.

Further, in the above-described embodiment, a case where the present invention is applied to an image forming apparatus 1 which is a monochrome printer that performs monochrome printing in an image forming unit 3 having one toner cartridge 21 corresponding to a black color has been described. .. The present invention is not limited to this, for example, an image forming apparatus having one toner cartridge corresponding to one color of yellow, magenta, cyan or black, and four corresponding to each color of yellow, magenta, cyan and black. The present invention is applied to various image forming devices such as an image forming device which is a color printer that performs color printing in an image forming unit having a toner cartridge and an image forming device having three or less or five or more toner cartridges. Is also good.

Further, in the above-described embodiment, the case where the present invention is applied to the image forming apparatus has been described. The present invention is not limited to this, and the present invention may be applied to devices such as facsimile machines, MFPs (MultiFunction Printers), and copiers.

Furthermore, the present invention is not limited to the above-described embodiments and other embodiments. That is, the present invention has an applicable scope to an embodiment in which each of the above-described embodiments and a part or all of the above-mentioned other embodiments are arbitrarily combined, and an embodiment in which a part is extracted. Is.

Further, in the above-described embodiment, the paper feed sub-roller 13 as the first roller member, the movable bearing 66 as the first holding portion, the spring 68 as the first urging member, and the movable portion are movable. The lever 44 constitutes a paper feed unit 40 as a medium transfer device, and the paper feed unit 40 as a medium transfer device and the housing 2 as a housing 2 form an image forming device 1 as an image forming device. The case of constructing is described. The present invention is not limited to this, and the medium transfer device is configured by the first roller member having various other configurations, the first holding portion, the first urging member, and the movable portion, and various other configurations. The image forming apparatus may be configured by the medium transporting device having the above configuration and the housing.

The present invention can be used not only in a computer for printing an image on an image forming apparatus, but also in various electronic devices such as an image scanner, a facsimile apparatus, a copying machine, and the like, which perform various processing related to an image.

1 ... Image forming device, 2 ... Housing, 2A ... Housing opening, 3 ... Image forming part, 10 ... Print medium supply part, 11 ... Paper cassette, 12 ... Paper feed roller, 13 …… Paper feed sub-roller, 14 …… Separation roller, 15 …… Intermediate transfer roller, 16 …… Pinch roller, 17 …… Resist roller, 18 …… Pressure roller, 19 …… Feeding sensor, 20 …… Writing sensor, 21 ... Toner cartridge, 22 ... Image drum, 23 ... Exposure head, 24 ... Transfer roller, 25 ... Fixing unit, 26 ... Heat roller, 27 ... Pressurized roller, 28 ... Emission sensor, 29, 30 ... Discharge roller, 31, 32 ... Pinch roller, 33 ... Discharge tray, 39 ... Paper unit exterior, 40 ... Paper unit, 41 ... Paper shaft, 42 ... Paper frame, 42A, 42D ... Spring support boss, 42B ... Roller support surface, 42F ... Paper feed sub-roller other end fitting hole, 42C, 42E ... Guide, 44 ... Movable lever, 44G ... Movable lever grip Unit, 44Af ... Paper feed roller movable bearing accommodating unit, 44Ab ... Paper feed sub roller movable bearing accommodating unit, 44S ... Movable bearing accommodation space, 44W ... Movable bearing support wall, 44R ... Movable bearing fitting groove, 44P …… Movable bearing positioning surface, 46 …… Bearing, 48 …… Gear, 49 …… Coupling, 50 …… Movable bearing, 50LS …… Movable bearing left side surface, 50RS …… Movable bearing right side surface, 50RS1 …… Parallel surface , 50RS2 ... Inclined surface, 50S ... Spring fixing part, 50A ... Paper feed roller fitting hole, 50ASu ... Paper feed roller fitting hole upper inner wall surface, 50ASd ... Paper paper roller fitting hole lower inner wall surface, 50ASl ... Paper feed roller fitting hole left inner wall surface, 50C ... Movable lever fitting protrusion, 50T ... Contact surface, 52 ... Spring, 54 ... Paper feed roller shaft, 54K ... Paper feed roller rubber holding Part, 54F ... Paper feed roller shaft part Flange, 54M ... Fitting part, 54B ... Paper feed roller boss part, 56 ... Paper feed roller rubber, 60 ... Paper feed sub roller shaft part, 60K ... Paper feed sub roller rubber holding 60F ... Paper feed sub-roller shaft flange, 60G ... Paper feed sub-roller shaft gear, 60S ... Paper feed sub-roller shaft shaft, 60S1 ... Paper feed sub-roller shaft shaft one end, 60S2 ... Paper feed sub-roller Shaft shaft other end, 62 ... Paper feed sub-roller rubber, 66 ... Movable bearing, 66LS ... Movable bearing left side, 66RS ... Movable bearing right side, 66RS1 ... Parallel surface, 66RS2 ... Inclined surface, 6 6S …… Spring fixing part, 66A …… Paper feed sub-roller one end fitting hole, 66ASu …… Paper feed sub-roller one end fitting hole upper side surface, 66ASd …… Paper feed sub-roller one end fitting hole lower side surface, 66ASl …… Paper feed sub-roller end fitting hole left side, 66C ... movable lever fitting protrusion, 66T ... contact surface, 68 ... spring, 70 ... idle gear, 72 ... movable shaft, 72S ... inclined surface, D1 ... Paper feed roller fitting depth, D2 ... Paper feed sub roller fitting depth, P ... Paper, Du ... Roller urging direction, De ... Roller retracting direction.

Claims (13)

A first roller member that rotates around a rotation axis and conveys a medium,
A first holding portion that rotatably holds the first roller member,
A first urging member that generates an urging force that urges the first roller member in the first direction along the rotation axis direction.
It has a movable portion that engages with the first holding portion and can move together with the first holding portion in a second direction opposite to the first direction.
The medium transfer device, characterized in that the first holding portion is movable in the second direction with respect to the movable portion. The first holding portion is
It has an engaged portion that engages with the engaging portion of the movable portion, and has an engaged portion.
When the engaged portion engages with the engaging portion, the engaged portion moves in the second direction together with the movable portion.
The engaged portion is
The medium transfer device according to claim 1, wherein when the first holding portion moves in the second direction with respect to the movable portion, the first holding portion is separated from the engaging portion. The first holding portion has a normal line on the roller removing direction side, which is moved when the first roller member is removed from the first holding portion, on the first direction side. The medium transfer device according to claim 1 or 2, wherein an inclined surface is formed toward the roller removal direction side with respect to the direction. When the first roller member that moves from the roller removal direction side to the roller mounting direction side in the direction opposite to the roller removal direction comes into contact with the inclined surface, the first holding portion is the first. The medium transfer device according to claim 3, wherein the device moves in the direction of 2. The medium transport according to any one of claims 1 to 4, wherein the movable portion is formed with a grip portion that projects outward from an exterior portion that covers at least a part of the first roller member. Device. Further having a positioning unit provided on the opposite side of the first holding portion with respect to the rotation axis direction and positioning the position of the first roller member in the rotation axis direction across the first roller member. The medium transfer device according to any one of claims 1 to 5. The medium transfer device according to any one of claims 1 to 6, wherein the first holding portion is a movable bearing that holds the shaft portion of the first roller member. The medium transfer device according to any one of claims 1 to 6, wherein the first holding portion is a movable shaft that is fitted into a hole portion of the first roller member. A second roller member that is arranged on the downstream side or the upstream side of the medium in the transport direction with respect to the first roller member, rotates about a rotation axis, and transports the medium.
A second holding provided with respect to the first roller member and the second roller member on the same side as the first holding portion in the direction of the rotation axis to rotatably hold the second roller member. Department and
It has a second urging member that urges the second holding portion in the first direction.
The movable portion engages with the second holding portion and can move in the second direction together with the second holding portion.
The medium transfer device according to any one of claims 1 to 8, wherein the second holding portion is movable in the second direction with respect to the movable portion. The medium transfer device according to claim 9, wherein the first holding portion and the second holding portion can move independently of each other in the second direction with respect to the movable portion. .. The medium transfer device according to claim 9, wherein the movable portion moves the first holding portion and the second holding portion by the same distance from each other in the second direction. The first roller member and the second roller member are sandwiched between the first roller member and the second roller member, which are provided on the opposite sides of the first holding portion and the second holding portion in the rotation axis direction. Further, it has a positioning unit for positioning the position of the second roller member in the rotation axis direction.
Claims 9 to 9, wherein the positioning portion with which the first roller member abuts and the positioning portion with which the second roller member abuts are at similar positions with respect to the rotation axis direction. Item 2. The medium transfer device according to any one of Items 11. The medium transfer device according to any one of claims 1 to 12,
An image forming apparatus comprising a housing provided with a housing opening for accommodating the medium transporting device and exposing at least a part of the medium transporting device to the outside.

Images