JPH1191963A - Sheet cassette and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the number of parts to simplify the constitution and improve operability by constructing the apparatus so that when a sheet cassette is inserted, an engagement member is turned to such a position as to put a sheet conveying means in the operable state, and when the sheet cassette is drawn out, it is turned such a position as to put the sheet conveying means in non-operable state. SOLUTION: When a sheet cassette 28 is put in a draw-out position, an engagement member 28 is turned clockwise by its dead load to be in the retreat position. In such a condition, when the sheet cassette B is inserted, an engagement part 28a of the engagement member 28 is inserted in the apparatus main body A. A contact part is brought into contact with a locking member 31, the engagement member 28 is turned so that the locking part is submerged under a locking member 31, and when it reaches a storing position, a cam member 32 is pushed up by the engagement member 28a and turned, and a pickup roller is lowered to be in the sheet conveyance enabled state. In drawing out the sheet cassette B, on the contrary, with the rotation of the engagement member 28, the cam member 32 is turned and the pickup roller is lifted to be in the non-conveyance state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet cassette removably mounted at a storage position and a pull-out position of an image forming apparatus main body, and an image forming apparatus capable of mounting the same.

[0002]

[Prior art]

[0003]

2. Description of the Related Art At present, image forming apparatuses such as copying machines are widely used in offices and the like. However, in order to cope with diversification of copies, a plurality of image forming apparatuses each storing sheets of different sizes are used. Many sheet cassettes can be mounted. When a plurality of sheet cassettes are mounted in this way, a so-called front-loading method is generally adopted in which the sheet cassettes can be inserted and removed from the front of the apparatus in terms of operability of the cassettes and apparatus space. is there.

In the case of a sheet cassette which is detachably inserted into and detached from the apparatus main body, a pickup roller for feeding sheets when the cassette is inserted into the storage position has a structure as shown in FIG. 6, for example. When the cassette is pulled out and the cassette is pulled out, the pickup roller is retracted from the sheet in the cassette.

FIGS. 6 (a) and 6 (b) show a conventional sheet cassette mounting structure, in which (a) is a sectional view of a state in which the cassette is pulled out, and (b) is a sectional view of the state in which the cassette is inserted, as viewed from the front in the sheet feeding direction. . As shown in FIG. 6, an engaging member 52 also serving as a handle is rotatable around a shaft 53 at the front cover 51 of the cassette body 50, and a spring (not shown) shown in FIG.
Is mounted so as to be urged in the direction of arrow p.
The engaging member 52 has a contact portion 52a and a locking portion 52b. When the cassette is pulled out, the locking portion 52b is
Abuts 54.

The holding member 54 is rotatable in the horizontal direction about a shaft 55, and is urged in the direction of arrow q by a spring (not shown). When the cassette is inserted in the direction indicated by the arrow r, the cassette abuts on a locking member 56 provided on the apparatus main body and rotates in the horizontal direction as shown in FIG. 6B. . Therefore, the locked state of the engaging member 52 is released, and the engaging member 52 rotates in the
While being locked to 56a, the contact portion 52a is lifted upward to rotate the cam member 57 provided on the apparatus main body.

The cam member 57 is connected to an elevating mechanism of the pickup 58, and the rotation of the cam member 57 causes the pickup roller 58 to descend to come into contact with the sheet S stored in the cassette body 50, thereby supplying the sheet S. It can be sent.

On the other hand, when pulling out the cassette, if the handle 52c of the engaging member 52 is rotated in the direction of the arrow s in FIG. 6B, the cam member 57 is not pushed up by the contact portion 52a. The member 57 rotates to raise the pickup roller 58 and retract the sheet S. When the cassette is pulled out in this state, as shown in FIG. 6 (a), the holding member 54 stops rotating by the locking member 56 and returns to the direction of the arrow q to lock the locking portion 52b.

As described above, the pickup roller 58 is switched between the operable state and the non-operable state in conjunction with the insertion / removal of the cassette.

[0010]

However, in the above-mentioned conventional example, the number of components is large and the mechanism is complicated, for example, the engaging member 52 also serves as a handle member. The engaging member 52 must be rotated by reliably pulling the portion 52c, and the operability is cumbersome.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to reduce the number of parts, simplify the configuration, and provide an easy-to-operate sheet cassette and an image using the same. A forming apparatus is provided.

[0012]

A typical configuration according to the present invention for achieving the above object is to store a sheet in a sheet cassette detachably attached to a storage position and a drawer position of an image forming apparatus main body. A cassette main body, a first position in which the sheet conveying means of the image forming apparatus main body is operable when the cassette main body is inserted into the storage position, and a sheet when the cassette main body is pulled out to the pull-out position. An engagement member rotatable with respect to a second position for disabling the conveyance unit, wherein the engagement member is provided on the image forming apparatus main body when the cassette main body is inserted into the storage position. The cassette body is configured to rotate to the first position in contact with the locking member, and to retract from the locking member and rotate to the second position when the cassette body is pulled out to the withdrawn position. And wherein the are.

In the above construction, when the sheet cassette is inserted, the engaging member is rotated to a position where the sheet conveying means can be operated, and when the sheet cassette is pulled out, the position where the sheet conveying means is not operated. To rotate. As described above, since the engagement member rotates in conjunction with the insertion and removal of the sheet cassette, no special operation such as a handle is required,
The operability can be improved by simplifying the configuration.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a sheet cassette according to an embodiment of the present invention and an image forming apparatus using the same will be specifically described with reference to FIGS. 1 is a partial perspective explanatory view centering on an engaging member of the sheet cassette, FIG. 2 shows a state of the engaging member when the sheet cassette is inserted and removed, (a) shows a state where the cassette is pulled out,
FIG. 3B is a cross-sectional explanatory view of the state in which the sheet cassette is being inserted, FIG. 3C is an explanatory view of the relationship between the engaging member and the feeding roller, and FIG. FIG. 5 is an explanatory diagram showing another embodiment of the engagement configuration of the sheet cassette.

Here, the overall configuration of the image forming apparatus main body will be described first, and then the configuration of the sheet cassette will be described.

{Description of Image Forming Apparatus Main Body} In FIG. 4, the image forming apparatus main body A has a scanner section A1 serving as image reading means for reading image information of a document at an upper portion thereof.
An image forming section A2 serving as image forming means is provided below the
Further, a sheet feeding portion A3 is provided below the lower portion.

The scanner unit A1 includes a scanning system light source 1, a platen glass 2, an openable document pressure plate 3, a mirror 4, a lens 5, and the like. Then, a book document, a sheet document, or the like, such as a book, thick paper, or curled paper, is placed on the platen glass 2 with the document surface facing down. When the key is pressed, the scanning system light source 1 scans the lower part of the platen glass 2 in the direction of arrow a in FIG. 4 to read image information on the document surface, and irradiates the photosensitive drum with light according to the image information.

On the other hand, four sheet cassettes B are mounted on a sheet feeding section A3 disposed below the image forming section A2, and sheets S of a size selected from each cassette B are conveyed by conveying means. And a retard roller (a rotator that rotates in the direction in which the sheet is returned) and a feed roller (a rotator that rotates in the direction in which the sheet is fed) that are fed out by the pickup roller 6 that is a feeding rotator that forms the separation rotator. After being separated and fed one by one by a separation roller pair constituted by 8, the sheet is fed and guided by a guide path 9, and is conveyed via a conveyance roller pair 10, which forms a conveyance rotating body, and further via a guide path 11. It is configured to be transported.

The leading end of the conveyed sheet S is detected by a registration sensor 13 provided immediately before the registration roller pair 12, and in response to this detection signal, the sheet S is synchronized with an image forming operation of an image forming unit A2 described later. Is transported to the image forming section A2 by the registration roller pair 12.

The image forming section A2 includes a primary charger 14, an electrophotographic photosensitive drum 15, a developing device 16, a transfer charger 17 and the like. Then, a latent image is formed on the surface of the photosensitive drum 15 uniformly charged by the primary charger 14 by exposure from the above-described scanner unit A1, and this latent image is developed with a toner by the developing unit 16 to form a visible image. Become Then, the toner image is transferred to the sheet S conveyed by the registration roller pair 12 by applying a voltage of the transfer charger 17.

The toner remaining on the photosensitive drum 15 after the transfer of the toner image onto the sheet S is removed by the cleaner 18.

On the other hand, in FIG. 4, reference numeral 19 denotes a conveying belt for conveying the sheet on which the toner image is formed, 20 denotes a fixing device,
21 and 22 are discharge rollers. The sheet S to which the toner image has been transferred is conveyed to a fixing device 20 by a conveying belt 19, heated and pressed to fix the toner image on the sheet surface, and then discharged out of the apparatus by discharge rollers 21 and 22.

When an image is recorded on both sides of a sheet, when the sheet discharged from the fixing device 20 passes through the flapper 23, the discharge roller 22 reverses, and the sheet is re-conveyed by the re-convey roller 24 and the re-convey path. The sheet is conveyed again to the image forming section via the sheet 25 and forms an image on the back side of the sheet.

{Description of Sheet Cassette} As described above, the four sheet cassettes B can be inserted into and retracted from the front of the apparatus at the storage position and the extraction position of the apparatus main body along a guide rail (not shown). . The four cassettes B have the same configuration except for the size of sheets that can be stored.

As shown in FIGS. 1 and 2, the sheet cassette B has a front cover 27 at the front of a cassette body 26 for storing sheets S. Inside the front cover 27, a substantially L-shaped engaging member 28 is provided.
The bearing 29a, 29b fixed to the shaft 27 pivots between a locking position (first position) for locking with a locking member of the apparatus main body, which will be described later, and a retracted position (second position) separated from the locking position. 28
It is pivotally supported about e.

An engaging portion 28a is formed at the free end of the horizontal portion of the engaging member 28, and the engaging portion 28a
It extends to the cassette body 26 side through a hole formed in the hole 27.

As shown in FIG. 2, the image forming apparatus main body A to which the sheet cassette B can be mounted has a locking member 31 fixed inside the main body cover 30 and a cam member 32 rotatably mounted thereon. I have. The locking member 31 locks the engaging member 28 of the sheet cassette B, and the cam member 32
3, constitutes switching means for switching the pickup roller 6 between an operable state and a non-operable state by the rotation of the engaging member 28. As shown in FIG.

A stopper 34 is pivotally supported inside the front cover 27 so as to be rotatable about a bearing 34a. The stopper 34 includes a spring hook 34c provided at one end and a front cover.
Spring hung on front cover spring hook 27a provided on 27
The rotation area is regulated by 35 in the state of being urged in the direction of the arrow g and abutting against the abutting portion 27b.

Further, at the other end of the stopper 34, when the cassette B is inserted into the apparatus main body A, the stopper 34 comes into contact with the tapered portion 36a of the hook 36 provided on the apparatus main body A side.
The hook 34 rotates in the direction of arrow h, and has a hook portion 34b that, when it gets over the tapered portion 36a, rotates in the direction of arrow g by the force of the spring 35 and enters the holding portion 36b.

Here, the relationship between the engaging member 28, the locking member 31, and the cam member 32 when the sheet cassette B is inserted and removed will be described.

When the sheet cassette B is in the pulled-out position as shown in FIG. 2A, the engaging member 28 is
Since the center of gravity 28b is located between the center of gravity and the center of gravity 28e, it is rotated in the direction of arrow a by its own weight and located at the retracted position.

In this state, the sheet cassette B is inserted as shown in FIG.
As shown in FIG. 7, when the member is inserted in the direction of arrow b, the engaging portion 28a of the engaging member 28 is inserted into the apparatus main body without abutting against the main body cover 30 or the locking member 31 of the apparatus main body A. Then, when the cassette B is inserted and reaches the position shown in FIG. 2B, the contact portion 28c of the engaging member 28 contacts the locking member 31, and
When the cassette B is inserted as it is, the engaging member 28 rotates and the engaging portion 28d continuous with the abutting portion 28c sinks under the engaging member 31 and is held in a state of contact (FIG. 2 (c)). reference). When the cassette B is inserted to the storage position of the apparatus main body in this state, as shown in FIG. 2C, the cam member 32 is pushed up by the engaging portion 28a which has been rotated and moved upward.
The cam member 32 rotates.

The rotation of the cam member 32 is in the direction of the arrow c in FIG. 3, and the rotation of the cam member 32 causes the pickup roller 6 to move down, so that the pickup roller 6 comes into pressure contact with the uppermost portion of the sheets S stacked and stored in the cassette B. Then, the pickup roller 6 enters a state in which the sheet can be conveyed (a state in which the conveying unit can operate).

When the cassette B is inserted to the storage position, the stopper 34 enters the holding portion 36b after the hook portion 34b has climbed over the tapered portion 36a of the hook 36. At this time, the cassette B is moved by an urging means (not shown) as shown in FIG.
And is positioned at a predetermined position in a state where the hook portion 34b is hooked on the holding portion 36b.

When the recording start button is pressed with the sheet cassette B mounted as described above, the pickup roller 6 rotates as described above to feed the sheet, and an image is formed on the sheet.

Next, when the sheet cassette B is to be pulled out, the cassette B is pulled out in the direction of arrow d in FIG.
The stopper 34 is hooked by the pull-out force of the cassette B.
34b comes out of the holding portion 36b while rotating in the direction of the arrow h in FIG. 1, and at the same time when the holding with the apparatus main body A is released,
The locking portion 28d and the contact portion 28c of the engaging member 28 at the locking position
Is disengaged from the locking member 31 of the apparatus main body, and the member 28 rotates clockwise by the center of gravity of the engaging member 28. As a result, the cam member 32 is not pushed up,
Is rotated in the direction of arrow e in FIG. 3, and the pickup roller 6 is raised by the urging of the urging means (not shown) and separated from the sheet S (the state shown by the two-dot chain line in FIG. 3). For this reason, the sheet is not conveyed even when the pickup roller 6 rotates (the conveying unit is in a non-operating state).

Therefore, even if the sheet cassette B is pulled out, the jam (paper jam) in which the sheet S is left in the apparatus main body because the pickup roller 6 is lifted up and separated from the sheet S as described above. Does not occur, and the engaging portion 28a of the engaging member 28 can be pulled out smoothly without hitting the locking member 31 of the apparatus main body or the main body cover 30.

With the above construction, there is no need to operate the handle when pulling out like a conventional sheet cassette. Therefore, such a member is unnecessary, the number of parts is reduced, and the construction is simple. And the operability of attachment and detachment is also improved.

[Other Embodiments] In the above-described embodiment, an example has been described in which the pickup roller 6 as the transport means is brought into an operable state and a non-operable state by inserting and removing the cassette B. However, a similar mechanism is used. Thereby, the contact and non-contact of the feed roller 7 and the retard roller 8 which are the separation rotating body as the transporting means may be switched so that the transporting means is in an operable state and a non-operating state. .

With the above arrangement, as shown in FIG. 3, for example, when the cassette B is pulled out while the sheet S is held between the separation rotating members 7 and 8, the sheet S jams between itself and the apparatus main body. Can be taken out without doing anything.

Further, in the above-described embodiment, an example is shown in which the engagement member 28 is rotated by the position of the center of gravity of the engagement member 28, but it may be configured as shown in FIG. FIG. 5 is an explanatory view showing an embodiment in which the engaging member 28 is biased by a spring 33. The other configuration is the same as that of the first embodiment.

By arranging the engagement member 28 to be urged in the direction of arrow f by the spring 33 as described above, the number of components is increased by one in comparison with the first embodiment. However, since the engaging member 28 is urged in the direction of the arrow f without considering the relationship of the center of gravity between the engaging member 28 and the rotation axis thereof, the degree of freedom in the shape of the member 28 is increased. It is possible,
The effect of increasing the degree of freedom in design can be obtained.

In the above-described embodiment, a copying machine is described as an example of an image forming apparatus using a sheet cassette. However, the present invention can be applied to other image forming apparatuses such as a printer and a facsimile apparatus. It is.

Further, the feeding rotator and the separating rotator constituting the sheet conveying means do not have to be roller-shaped like the pickup roller 6 and the feed roller 7 of the above-described embodiment. It may be configured.

[0045]

The present invention is constructed as described above.
When the sheet cassette is inserted, the engaging member is rotated to a position where the sheet conveying means can be operated, and when the sheet cassette is pulled out, the engaging member is rotated to a position where the sheet conveying means is not operated. As described above, since the engagement member rotates in conjunction with the insertion and removal of the sheet cassette, a special operation such as a handle is not required, and the operability can be improved by simplifying the configuration.

[Brief description of the drawings]

FIG. 1 is a partial perspective view mainly illustrating an engagement member of a sheet cassette.

FIGS. 2A and 2B show a state of an engagement member when a sheet cassette is inserted and removed, wherein FIG.
FIG. 4 is a cross-sectional explanatory view of a state during insertion, and FIG. 4C is a state of being inserted and mounted.

FIG. 3 is a diagram illustrating a relationship between an engagement member and a feeding roller.

FIG. 4 is a diagram illustrating the overall configuration of an image forming apparatus in which a sheet cassette is mounted.

FIG. 5 is an explanatory diagram showing another embodiment of the engagement configuration of the sheet cassette.

6A and 6B show a conventional sheet cassette mounting configuration, and FIG.
FIG. 3B is an explanatory cross-sectional view of the state in which the cassette is pulled out, and FIG.

[Explanation of symbols]

 A: Image forming apparatus main body A1: Scanner section A2: Image forming section A3: Sheet feeding section B: Sheet cassette S: Sheet 1: Scanning light source 2: Platen glass 3: Original platen 4: Mirror 5: Lens 6: Pickup Roller 7… Feed roller 8… Retard roller 9… Guide path 10… Transport roller pair 11… Guide path 12… Register roller pair 13… Register sensor 14… Primary charger 15… Electrophotosensitive drum 16… Developer 17… Transfer Charger 18 Cleaner 19 Conveyor belt 20 Fixing device 21, 22 Discharge roller 23 Flapper 24 Reconveying roller 25 Reconveying path 26 Cassette body 27 Front cover 27a Front cover spring hook 27b Part 28 ... Engaging member 28a ... Engaging part 28b ... Center of gravity 28c ... Contact part 28d ... Locking part 28e ... Shaft 29a, 29b ... Bearing 30 ... Body cover 31 ... Locking member 3 2… Cam member 33… Spring 34… Stopper 34a… Bearing part 34b… Hook part 34c… Spring hang part 35… Spring 36… Hook 36a… Taper part 36b… Holding part

Claims (4)

[Claims] 1. A sheet cassette detachably mounted at a storage position and a pull-out position of an image forming apparatus main body, wherein: a cassette main body for storing sheets; and the image forming apparatus main body when the cassette main body is inserted into the storage position. An engagement member rotatable between a first position for bringing the sheet conveying means into an operable state, and a second position for bringing the sheet conveying means into a non-operating state when the cassette body is pulled out to the pull-out position. Wherein the engaging member abuts on a locking member provided on the image forming apparatus main body when the cassette main body is inserted into the storage position, and rotates to the first position to move the cassette main body to the first position. The sheet cassette is configured to retreat from the locking member and rotate to the second position when the sheet cassette is pulled out to a pull-out position. 2. An image forming apparatus for conveying a sheet from a mounted sheet cassette to form an image, wherein the sheet cassette according to claim 1, an engaging member for engaging an engaging member of the sheet cassette, Sheet transport means for transporting the sheets stored in the sheet cassette; switching means for switching the sheet transport means between an operable state and a non-operable state by rotation of an engaging member of the sheet cassette; and an image on the transported sheets. An image forming apparatus, comprising: 3. An image forming apparatus according to claim 2, wherein said switching means comprises a cam member, and an engaging member of said sheet cassette is engageable with said cam member. 4. The sheet conveying means which is switched to an operable state by the switching means is a feeding rotator for feeding sheets from the sheet cassette, or a separating means for separating sheets fed from the feeding rotator. 3. The image forming apparatus according to claim 2, wherein the image forming apparatus is a rotating body.