CN212965747U

CN212965747U - Toner box

Info

Publication number: CN212965747U
Application number: CN202022174517.6U
Authority: CN
Inventors: 深町泰生
Original assignee: Brother Industries Ltd
Current assignee: Brother Industries Ltd
Priority date: 2019-09-30
Filing date: 2020-09-28
Publication date: 2021-04-13
Anticipated expiration: 2030-09-28
Also published as: JP2021056400A

Abstract

The utility model provides a toner box, comprising: a casing capable of accommodating toner inside; a first gear capable of rotating about a first axis extending in the axial direction and located on the outer surface of the casing; a rib, the rib being any one of a first rib and a second rib, for determining the kind of the toner cartridge, having flexibility, the first rib representing the toner cartridge of the first kind, the A second rib represents a second type of toner cartridge that is different from the first type; and a second gear is rotatable about a second axis extending in the axial direction, and can pass and rotate with the first type of toner. The gears cooperate to rotate from a first position to a second position and then stop, enabling installation and removal of the first rib or the second rib.

Description

Toner box

Technical Field

The present invention relates to a toner cartridge used in an image forming apparatus.

Background

Among image forming apparatuses having a toner cartridge, there is known an image forming apparatus capable of determining the specification of the toner cartridge. For example, a toner cartridge is known in which a protrusion moves with rotation of a detection gear. The image forming apparatus detects the protrusion by a sensor, thereby detecting the specification of the toner cartridge. The detection gear can advance and retreat so that the projection does not interfere with mounting and demounting of the cartridge.

SUMMERY OF THE UTILITY MODEL

However, in the above structure, since the detection gear advances and retreats, the structure of the toner cartridge is complicated.

(1) In order to achieve the above object, the present invention provides a toner cartridge including: a housing capable of accommodating toner therein; a first gear rotatable about a first axis extending in an axial direction, located on an outer surface of the housing; a rib having flexibility for specifying a type of the toner cartridge, the rib being one of a first rib and a second rib, the first rib representing a first type of the toner cartridge, the second rib representing a second type of the toner cartridge different from the first type; and a second gear rotatable about a second axis extending in the axial direction, rotatable from a first position to a second position by being engaged with the first gear that rotates and then stopped, the first rib or the second rib being attachable and detachable.

(2) The toner cartridge of the present invention, wherein the second gear is attachable to the first rib or the second rib in such a manner that the first rib or the second rib protrudes from the second gear in the axis direction.

(3) The utility model discloses a toner box, the second gear still includes: a gear portion or a friction member formed at a portion of a circumferential surface of the second gear, for being engaged with the first gear; and a non-engagement portion that is disposed in the remaining portion of the circumferential surface and does not engage with the first gear.

(4) The utility model discloses a toner box, the friction member is rubber.

(5) The utility model discloses a toner box still includes the agitator, the agitator have the axle and with the stirring vane that the axle rotated together, the agitator is used for the stirring toner in the casing, first gear is located the tip of axle.

(6) The utility model discloses a toner box still includes the gear cover, the gear cover covers first gear with at least a part of second gear has the messenger the opening that a part of rib exposes.

Drawings

Fig. 1 is a diagram showing an outline structure of a printer according to an embodiment.

Fig. 2 is a sectional view showing the structure of the toner cartridge.

Fig. 3 is a perspective view showing the entire toner cartridge.

Fig. 4 is a perspective view showing a member on the toner cartridge side in an exploded manner.

Fig. 5A is a perspective view of the second gear viewed from one side, and fig. 5B is a perspective view viewed from the other side.

Fig. 6A is a perspective view showing a rib representing a standard capacity, fig. 6B is a perspective view showing a rib representing a large capacity, and fig. 6C is a perspective view showing a rib representing an extra large capacity.

Fig. 7 is a view of the toner cartridge in a state where the gear cover is removed as viewed from the one side in the axial direction, showing a state where the first gear, the second gear, and the lever are located at initial positions.

Fig. 8 is a view of the toner cartridge in a state where the gear cover is removed as viewed from the one side in the axial direction, showing a state where the second gear starts to mesh with the first gear.

Fig. 9 is a view of the toner cartridge in a state where the gear cover is removed as viewed from the one side in the axial direction, showing a state where the rib of the second gear presses the lever.

Fig. 10 is a view of the toner cartridge in a state where the gear cover is removed as viewed from the one side in the axial direction, showing a state where the rib of the second gear is removed from the lever.

Fig. 11 is a view of the toner cartridge in a state where the gear cover is removed as viewed from the one side in the axial direction, and shows a state where the engagement between the first gear and the second gear is released.

Fig. 12 is a timing chart showing the first gear, the second gear, the detection signal of the optical sensor in the case where the rib of the standard capacity is mounted, the detection signal of the optical sensor in the case where the rib of the large capacity is mounted, and the detection signal of the optical sensor in the case where the rib of the extra large capacity is mounted.

Fig. 13A to 13C are views of one side of the toner cartridge as viewed from above, fig. 13A showing a state of the rib in the middle of mounting the toner cartridge, fig. 13B showing a state of the rib in a case where mounting is completed, and fig. 13C showing a state where the rib presses the lever.

Detailed Description

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in fig. 1, a laser printer 1 as an example of an image forming apparatus mainly includes a main body casing 2, a paper feed section 3, an image forming section 4, and a control unit CU.

The body casing 2 has a front cover 2A and a paper discharge tray 2B located at an upper portion of the body casing 2. The main body casing 2 includes a paper feeding unit 3 and an image forming unit 4. By opening the front cover 2A, the toner cartridge 10 can be attached and detached.

The paper feed unit 3 accommodates sheets S. The paper feed unit 3 feeds the sheets S one by one to the image forming unit 4.

The image forming portion 4 includes a drum cartridge 5, a toner cartridge 10, an exposure device, a transfer roller 4B, and a fixing device 4C, which are not illustrated.

The toner cartridge 10 can be attached to and detached from the drum cartridge 5. The toner cartridge 10 is attached to and detached from the laser printer 1 in a state where the toner cartridge 10 is attached to the drum cartridge 5. The drum cartridge 5 includes a frame 5A and a photosensitive drum 5B rotatably supported by the frame 5A.

As shown in fig. 2, the toner cartridge 10 includes a housing 11, a developing roller 12, a supply roller 13, and an agitator 14.

The housing 11 can accommodate the toner T inside thereof.

The developing roller 12 includes a developing roller shaft 12A and a roller portion 12B. The roller portion 12B covers the outer peripheral surface of the developing roller shaft 12A. The roller portion 12B is made of conductive rubber or the like. The developing roller 12 is rotatable about a developing roller axis 12X extending in an axial direction of the agitator 14 (hereinafter referred to as "axial direction").

The feed roller 13 includes a feed roller shaft 13A and a roller portion 13B extending in the axial direction. The roller portion 13B covers the outer peripheral surface of the supply roller shaft 13A. The roller portion 13B is made of sponge or the like. The supply roller 13 is rotatable about a supply roller shaft 13A.

The agitator 14 includes a shaft 14A and an agitating blade 14B. The shaft 14A is rotatable about a first axis 1X extending in the axial direction. The stirring blade 14B rotates together with the shaft 14A. The agitator 14 can agitate the toner T with the rotating agitating blade 14B.

Further, as shown in fig. 1, the transfer roller 4B faces the photosensitive drum 5B. The transfer roller 4B sandwiches the sheet S between it and the photosensitive drum 5B and conveys the sheet S.

The photosensitive drum 5B is charged by a charger (not shown) and exposed by an exposure device, thereby forming an electrostatic latent image. The drum cartridge 5 supplies toner T to the electrostatic latent image, thereby forming a toner image on the photosensitive drum 5B. The sheet S fed from the sheet feeding unit 3 is transferred with the toner image on the photosensitive drum 5B while passing between the photosensitive drum 5B and the transfer roller 4B.

The fixing device 4C thermally fixes the toner image transferred onto the sheet S on the sheet S. The sheet S on which the toner image is thermally fixed is discharged to a discharge tray 2B outside the main body casing 2.

The control unit CU is a unit that controls the overall operation of the laser printer 1.

The laser printer 1 includes a sensor 7. The sensor 7 is a sensor for detecting whether or not the toner cartridge 10 is new and the specification of the toner cartridge 10. The sensor 7 includes a lever 70 swingably supported by the body housing 2, and an optical sensor 7B. The lever 70 is located at a position where it can contact a rib 300 described later. The optical sensor 7B is connected to the control unit CU, and outputs a detection signal to the control unit CU. The control unit CU is configured to be able to determine the specification of the toner cartridge 10 and the like based on the signal received from the optical sensor 7B. The optical sensor 7B detects the displacement of the lever 70, and sends a detection signal to the control unit CU. More specifically, for the optical sensor 7B, for example, a sensor unit including a light emitting portion and a light receiving portion is used. This will be explained in detail later.

Next, a specific structure of the toner cartridge 10 will be described.

As shown in fig. 3 and 4, the toner cartridge 10 has a gear cover 31 and a coupling portion 32 on one side in the axial direction of the housing 11.

The gear cover 31 has a coupling hole 31A and an opening 31B. The coupling hole 31A is a hole exposing the coupling portion 32. The gear cover 31 is fixed to the housing 11 by a plurality of screws 31N.

The coupling portion 32 has a recess 32A for receiving the driving force and a coupling gear 32B. The recess 32A is concave in the axial direction. The recess 32A is exposed from the coupling hole 31A of the gear cover 31. A fitting portion (not shown) is fitted in the recess 32A. The coupling portion 32 can rotate by receiving a driving force from the fitting portion. Note that the gear teeth of the coupling gear 32B are omitted in fig. 4.

The toner cartridge 10 includes a developing roller gear 33, a supply roller gear 34, an idle gear 35, a first gear 100, a second gear 200, and a rib 300 on one side in the axial direction of the housing 11. These gears are covered by a gear cover 31. In fig. 4, gear teeth of the developing roller gear 33, the supply roller gear 34, and the idle gear 35 are omitted. Further, gear teeth of the large diameter gear of the first gear 100 are omitted.

The gear cover 31 covers at least a portion of the first gear 100 and the second gear 200. In the present embodiment, the opening 31B of the gear cover 31 exposes a part of the second gear 200. The opening 31B exposes a part of the rib 300.

The developing roller gear 33 is located at an end of the developing roller 12. The developing roller gear 33 meshes with the coupling gear 32B.

The feed roller gear 34 is located at an end of the feed roller 13. The supply roller gear 34 meshes with the coupling gear 32B.

The idler gear 35 has a small diameter gear 35A and a large diameter gear 35B, and the diameter of the large diameter gear 35B is larger than that of the small diameter gear 35A. The small diameter gear 35A rotates together with the large diameter gear 35B. The large diameter gear 35B of the idle gear 35 meshes with the coupling gear 32B.

The first gear 100 is located at the end of the shaft 14A. That is, in the present embodiment, the first gear 100 is rotatable about the first axis 1X extending in the axial direction. The first gear 100 is located on the outer surface of the housing 11. The first gear 100 includes a small-diameter gear 110, a large-diameter gear 120, a circular plate portion 130, and a first protrusion 140.

The large diameter gear 120 has a larger diameter than the small diameter gear 110. The large diameter gear 120 rotates together with the small diameter gear 110. The large diameter gear 120 of the first gear 100 can be engaged with the small diameter gear 35A of the idle gear 35 to rotate.

The circular plate portion 130 is a circular plate and connects the small-diameter gear 110 and the large-diameter gear 120. The circular plate portion 130 extends in a direction intersecting the axial direction. Preferably, the circular plate portion 130 extends in a direction perpendicular to the axial direction.

The first protrusion 140 protrudes from the circular plate portion 130 toward one side in the axial direction. The first protrusion 140 extends in a direction intersecting the radial direction of the circular plate portion 130.

The second gear 200 is rotatable about a second axis 2X extending in the axial direction. The second gear 200 is located on the outer surface of the housing 11. As shown in fig. 5A and 5B, the second gear 200 has a body portion 210, a gear portion 220, a non-fitting portion 230, a mounting portion 240, and a second protrusion 250.

In the present embodiment, the body portion 210 is a circular plate. The gear portion 220 is provided on a portion of the circumferential surface of the body portion 210, and the non-fitting portion 230 is provided on the remaining portion of the circumferential surface of the body portion 210.

The gear portion 220 is constituted by a plurality of gear teeth provided on a part of the circumferential surface. The gear portion 220 can mesh with the small-diameter gear 110 of the first gear 100. The gear portion 220 receives a driving force from the first gear 100. Accordingly, the second gear 200 is rotated from the first position as the initial position shown in fig. 7 to the second position shown in fig. 11 by being engaged with the rotating first gear 100.

The non-engagement portion 230 is the remaining portion of the circumferential surface where no gear teeth are provided, and does not mesh with the small diameter gear 110 of the first gear 100. The non-engaging portion 230 is not engaged with the first gear 100. Therefore, after the second gear 200 moves from the first position to the second position, it stops at the second position where the non-engagement portion 230 faces the first gear 100 (small diameter gear 110) as shown in fig. 11.

The mounting part 240 is provided on a surface of one side of the body part 210. The attachment portion 240 has a holding frame 241 and a holding projection 242. The holding frame 241 is a frame for holding a part of the rib 300 so that the tip end portion of the rib 300 can be bent. The holding projection 242 is a projection projecting from the inside of the holding frame 241.

The second protrusion 250 is provided on the other side surface of the body part 210. The second protrusion 250 extends from the body portion 210 toward the other side of the axial direction. The second protrusion 250 can move the second gear 200 by being pressed by the first protrusion 140 of the first gear 100.

The rib 300 is a member for determining the kind of the toner cartridge 10. That is, the ribs 300 may have a variety of different shapes. As an example, the rib 300 has three different shapes. Specifically, as shown in fig. 6A to 6C, there are three different shapes of the rib 310, the rib 320, and the rib 330, which correspond to the standard capacity toner cartridge 10, the large capacity toner cartridge 10, and the extra large capacity toner cartridge 10, respectively.

The rib 310 is a rib representing a standard capacity toner cartridge 10. As shown in fig. 6A, the rib 310 has a rectangular shape. The rib 310 has a head end 311 and a base end 312. The head end 311 of the rib 310 is formed from a single strip having a dimension D1. The base end portion of the rib 310 is provided with a rib hole H.

The rib 320 is a rib indicating the large-capacity toner cartridge 10. As shown in fig. 6B, the rib 320 has a U-shape. The rib 320 has a head end 321 and a base end 322. The head end 321 of the rib 320 is made up of two strips of dimension D2, dimension D2 being smaller than dimension D1. A cut 320K is formed between the two strips. The base end portion of the rib 320 is provided with a rib hole H.

The rib 330 is a rib indicating the toner cartridge 10 of an extra large capacity. As shown in fig. 6C, the rib 330 has an L-shape. Rib 330 has a head end 331 and a base end 332. The head end 331 of the rib 330 is formed from a single strip having a dimension D2, dimension D2 being less than dimension D1. The base end portion of the rib 330 is provided with a rib hole H.

In the present embodiment, the second gear 200 can attach and detach the first rib or the second rib. When any one of the three kinds of

ribs

310, 320, and 330 is taken as the first rib, any one of the remaining two kinds is taken as the second rib. That is, the rib 300 is one of a first rib representing the first kind of toner cartridge 10 and a second rib representing the second kind of toner cartridge 10 different from the first kind.

The rib 300 has flexibility. The ribs 300 are made of, for example, a thin sheet (film) of polyethylene terephthalate or the like.

As shown in fig. 5A, the rib 300 (first rib or second rib) is mounted on the mount portion 240 of the second gear 200. Specifically, the rib 300 enters the holding frame 241 of the mounting portion 240, and the rib hole H is engaged with the holding projection 242. Since only a part of the rib 300 enters into the mount portion 240, the rib 300 protrudes from the second gear 200 in the axial direction. After the gear cover 31 is attached to the housing 11 of the toner cartridge 10, as shown in fig. 3, the tip end of the rib 300 protrudes from the opening 31B of the gear cover 31.

As shown in fig. 7, the lever 70 has a shaft portion 71, a contact portion 72, and a shielding portion 73. The shaft portion 71 is swingably supported by the main body case 2. The contact portion 72 extends from the shaft portion 71.

The shielding portion 73 extends from the shaft portion 71 toward the side opposite to the contact portion 72. The shielding portion 73 is a portion that shields light from the optical sensor 7B.

The lever 70 is movable between a first lever position, shown in fig. 7, and a second lever position, shown in fig. 9. When in the first lever position, the contact portion 72 is located on the rotational locus of the rib 300. The lever 70 is urged from the second lever position to the first lever position by a spring (not shown), and is held at the first lever position by a stopper (not shown). When located at the first lever position, light from the optical sensor 7B is blocked by the blocking portion 73.

The second lever position is a position in which the lever 70 is pressed by the rib 300 to move. When located at the second lever position, the light from the optical sensor 7B is not blocked by the blocking portion 73.

In the present embodiment, when the light from the optical sensor 7B is blocked by the lever 70, the control unit CU recognizes OFF; when the light from the optical sensor 7B is not blocked by the lever 70, the control unit CU recognizes ON. The opposite is also possible, i.e. when the light from the optical sensor 7B is blocked by the rod 70, the control unit CU recognizes ON; when the light from the optical sensor 7B is not blocked by the lever 70, the control unit CU recognizes OFF.

Next, the operation of the toner cartridge 10 having the above-described structure will be described with reference to fig. 7 to 13. In the timing chart of fig. 12, the state in which the first gear 100 and the second gear 200 rotate is represented by ON, and the state in which they do not rotate is represented by OFF. Further, it is assumed that the rib 310 of the toner cartridge 10 representing the standard capacity is attached to the second gear 200.

As shown in fig. 13A, when the toner cartridge 10 is attached to the body housing 2, the rib 300 flexes even if the rib 300 hits against other members such as a side wall of the body housing 2. Thus, as shown in fig. 13B, when the toner cartridge 10 is mounted at a predetermined position of the body housing 2, the flexed rib 300 returns to its original state.

When the toner cartridge 10 is a new product, the first gear 100 and the second gear 200 are located at the initial positions shown in fig. 7. As shown in fig. 3, when the second gear 200 is located at the initial position, the head end of the rib 310 is exposed through the opening 31B. As shown in fig. 7 and 12, when the second gear 200 is located at the initial position, the lever 70 is located at the first lever position, and the sensor 7 is OFF.

When the coupling portion 32 receives a driving force in the clockwise direction in fig. 7, the idle gear 35 rotates in the counterclockwise direction. At this time, since the first gear 100 is engaged with the idle gear 35, the first gear 100 starts to rotate clockwise (time t 0). When the first gear 100 rotates, the first protrusion 140 starts to move clockwise together with the first gear 100. Then, as shown in fig. 8, the first protrusion 140 reaches the second protrusion 250 of the second gear 200, and the first protrusion 140 starts to press the second protrusion 250. When the second protrusion 250 is pressed by the first protrusion 140, the second gear 200 rotates counterclockwise. Therefore, the gear portion 220 of the second gear 200 meshes with the first gear 100, and starts counterclockwise rotation (time t 1).

When the second gear 200 rotates counterclockwise, the rib 310 then comes into contact with the contact portion 72 of the lever 70. At this time, as shown in fig. 13C, the tip end of the rib 310 is not deflected. Thus, the rib 310 starts to press the lever 70. In this way, as shown in fig. 9, the lever 70 pressed by the rib 310 swings clockwise, moving from the first lever position to the second lever position. When the lever 70 is moved to the second lever position, the sensor 7 is ON (time t 2).

When the second gear 200 is further rotated, as shown in fig. 10, the rib 310 moves to a position not contacting the lever 70. Then, the lever 70 is moved from the second lever position (the two-dot chain line) to the first lever position (the solid line) by the urging force of the spring (not shown) (time t 5). Thereby, the lever 70 blocks the light of the optical sensor 7B, and the sensor 7 is OFF.

In this way, in the case where the rib 310 is attached to the second gear 200, the sensor 7 is ON during the first period T1 from the time T2 to the time T5 (refer to fig. 12), whereby the control device CU can determine that the toner cartridge 10 has the standard capacity.

Assuming that the rib 320 is mounted ON the second gear 200, the sensor 7 is ON, then OFF during the second period T2 from the time T2 to the time T3, and then ON again during the second period T2 from the time T4 to the time T5, whereby the control device CU can determine that the toner cartridge 10 has a large capacity.

Assuming that the rib 330 is mounted ON the second gear 200, the sensor 7 is ON during the second period T2 from the time T2 to the time T3, whereby the control device CU can determine that the toner cartridge 10 has an excessively large capacity.

When the second gear 200 further rotates, as shown in fig. 11, the second gear 200 is disengaged from the first gear 100 and stops rotating (time t 6). In this way, the second gear 200 is moved to the final position shown in fig. 11. In the final position, the second gear 200 is not meshed with the first gear 100, and therefore, the second gear 200 is maintained in the final position even if the first gear 100 continues to rotate. Further, since the lever 70 is held at the first lever position, the sensor 7 is held OFF.

When the toner cartridge 10, which is not a new product, is mounted in the body case 2 of the laser printer 1, the second gear 200 is located at the final position, and even if the coupling portion 32 is driven, the second gear 200 does not move from the final position. Therefore, the control device CU can determine that the toner cartridge 10 is not a new product.

According to the toner cartridge 10 described above, the kind of the toner cartridge 10 can be determined by attaching the first rib or the second rib to the second gear 200. Therefore, the specification of the toner cartridge 10 can be determined with a simple configuration. Further, since the rib has flexibility, as shown in fig. 13A, when the toner cartridge is mounted or dismounted, even if the rib hits against another member, the rib can flex so as not to hinder the mounting and dismounting operation.

Further, since the first rib or the second rib can be attached to the second gear 200 in such a manner as to protrude from the second gear 200 in the axial direction, the protruding portion of the first rib or the second rib is detected by the lever 70, and thus the kind of the toner cartridge 10 is easily determined.

Further, the second gear 200 can be rotated from the first position to the second position because of having the gear portion 220, and can be stopped after being rotated to the second position because of having the non-engaging portion 230.

Further, since the toner cartridge 10 has the gear cover 31, it is possible to suppress the first gear 100 and the second gear 200 from hitting other members when the toner cartridge 10 is mounted and dismounted.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. The specific structure may be appropriately changed without departing from the spirit of the present invention.

In the above embodiment, the rib 300 is in contact with the body housing 2 when the second gear 200 is located at the initial position and at the final position, but the rib 300 may not be in contact with the body housing 2 when the second gear 200 is located at the initial position and at the final position.

In the above embodiment, the ribs have three different shapes, but the ribs may have two shapes, or four or more shapes.

In the above embodiment, the first gear 100 is a gear that rotates together with the agitator, but the first gear may be a gear other than a gear that rotates together with the agitator.

In the above embodiment, the second gear has the gear portion 220 formed of a plurality of gear teeth to be engaged with the first gear 100, but the second gear may have a friction member to be engaged with the first gear by friction transmission. Such a friction member is, for example, rubber.

In the above embodiment, the toner cartridge and the drum cartridge are separate members, but they may be integrally configured.

In the above-described embodiment, the monochromatic laser printer is taken as an example of the image forming apparatus, but the image forming apparatus may be a color image forming apparatus, may be exposed by an LED, or may be a copying machine or a multifunction machine.

The elements in the above embodiments and modifications may be combined arbitrarily.

Claims

1. A toner cartridge, comprising:

a housing capable of accommodating toner therein;

a first gear rotatable about a first axis extending in an axial direction, located on an outer surface of the housing;

a rib having flexibility for specifying a type of the toner cartridge, the rib being one of a first rib and a second rib, the first rib representing a first type of the toner cartridge, the second rib representing a second type of the toner cartridge different from the first type; and

a second gear rotatable about a second axis extending in the axial direction, rotatable from a first position to a second position by being engaged with the first gear that rotates and then stopped, the first rib or the second rib being attachable and detachable.

2. The toner cartridge according to claim 1, wherein the second gear is capable of mounting the first rib or the second rib in such a manner that the first rib or the second rib protrudes from the second gear in the axis direction.

3. The toner cartridge according to claim 1 or 2, wherein the second gear further includes:

a gear portion or a friction member formed at a portion of a circumferential surface of the second gear, for being engaged with the first gear; and

and a non-engagement portion that is disposed in the remaining portion of the circumferential surface and does not engage with the first gear.

4. The toner cartridge of claim 3, wherein the friction member is rubber.

5. The toner cartridge according to claim 1, further comprising an agitator having a shaft and an agitating blade that rotates together with the shaft, the agitator configured to agitate the toner within the housing,

the first gear is located at an end of the shaft.

6. The toner cartridge according to claim 1, further comprising a gear cover that covers at least a portion of the first gear and the second gear, having an opening that exposes a portion of the rib.