Patent Grant
9329551
The present invention relates to a medium cassette for placing a medium to be supplied to an image forming apparatus, and to an image forming apparatus having the medium cassette.
A conventional image forming apparatus configured to perform a color printing operation or a monochrome printing operation is provided with a sheet cassette for placing a recording sheet to be printed. A regulating member is disposed in the sheet cassette for regulating a position of the recording sheet laterally and longitudinally, thereby securing printing position accuracy. The sheet cassette is configured such that the regulating member is not easily shifted (refer to Patent Reference).
Patent Reference: Japanese Patent Publication No. 2010-52858
In the conventional image forming apparatus disclosed in Patent Reference, when a maximum amount of sheets are placed in the sheet cassette, and the sheet cassette is attached to the conventional image forming apparatus, a large force may be applied to the regulating member. In this case, the regulating member may be shifted from a regular position. In order to prevent the regulating member from being shifted from the regular position, it may be configured such that the regulating member is attached to the sheet cassette with a relatively large force. However, in this case, a handling property such as adjusting the position of the regulating member may be suffered.
In view of the problems described above, an object of the present invention is to provide an image forming apparatus capable of securely maintaining a position of a regulating member without suffering the handling property of the regulating member even when a large impact is applied to the regulating member.
Further objects and advantages of the invention will be apparent from the following description of the invention.
In order to attain the objects described above, according to an aspect of the present invention, a medium cassette is configured to be held and attached to a main body of an image forming apparatus so that the medium cassette slides in an insertion direction or a pullout direction relative to the image forming apparatus.
According to the aspect of the present invention, the medium cassette includes a rear side guide for guiding a medium to be placed at a rear side in the pullout direction; a locking member disposed to be able to engage with a body of the medium cassette for regulating a position of the rear side guide relative to the body of the medium cassette; and a movement conversion member for converting a movement of the rear side guide generated by an impact when the medium cassette is attached to the main body of the image forming apparatus to a movement of the locking member in a direction that the locking member engages with the body of the medium cassette.
According to the aspect of the present invention, it is possible to hold the locking member with an enhanced force against an impact applied to the rear side guide when the medium cassette is attached to the main body of the image forming apparatus. Accordingly, it is not necessary to increase a locking force of the locking member, and to improve the handling property of the medium cassette such as adjusting a position thereof.
Hereunder, embodiments of the present invention will be explained with reference to the accompanying drawings. It should be noted that the present invention is not limited to the following description, and the embodiments can be modified within a scope of the present invention.
First Embodiment
A first embodiment of the present invention will be explained.
As shown in
In the first embodiment, the image forming apparatus 100 includes a sheet supply portion 102 to be driven with a driving unit (not shown) and a print timing adjusting portion 104. The sheet supply portion 102 is provided for drawing out the recording sheets placed in the sheet cassette 101 one by one from the uppermost sheet, and for transporting the recording sheet to the print timing adjusting portion 104 along a sheet transportation path. Further, the image forming apparatus 100 includes a sheet detecting portion 103 disposed on an upstream side of the print timing adjusting portion 104 in a sheet transportation direction. The sheet detecting portion 103 is provided for detecting the recording sheet passing there through, so that the sheet detecting portion 103 detects that the recording sheet is supplied to the print timing adjusting portion 104.
In the first embodiment, the image forming apparatus 100 further includes an image forming portion 105. The image forming portion 105 includes a photosensitive drum 115B for forming a toner image in black (B); a photosensitive drum 115B for forming a toner image in yellow (Y); a photosensitive drum 115M for forming a toner image in magenta (M); and a photosensitive drum 115B for forming a toner image in cyan (C). It should be noted that the photosensitive drum may be collectively referred to as the photosensitive drum 115 if it is not necessary to differentiate a color). The photosensitive drums 115 are arranged along the sheet transportation path from the upstream side in the sheet transportation direction to form the sheet transportation path in a linear shape.
In the first embodiment, the image forming portion 105 further includes an LED (Light Emitting Diode) head 114K disposed near the photosensitive drum 115K for exposing the photosensitive drum 115K to form a static latent image according to image data. Similarly, in the image forming portion 105, an LED head 114Y is disposed near the photosensitive drum 115Y; an LED head 114M is disposed near the photosensitive drum 115M; and an LED head 114C is disposed near the photosensitive drum 115C, respectively. After the LED heads 114K, 114Y, 114M, and 114C form the static latent images in each color on the photosensitive drums 115, a developing device (not shown) develops the static latent images to form toner images.
In the first embodiment, the image forming apparatus 100 further includes a transfer belt unit 113 and a fixing device 106 disposed on the downstream side of the transfer belt unit 113. The transfer belt unit 113 is provided for transporting the recording sheet transported from the print timing adjusting portion 104, so that the toner images formed on the photosensitive drums 115 are sequentially overlapped and transferred to the recording sheet while the recording sheet passes through the photosensitive drums 115. Accordingly, synchronizing with the print timing adjusting portion 104, the image forming portion 105 forms the toner images. Further, together with the transfer belt unit 113, the image forming portion 105 transports the recording sheet with the toner image overlapped and transferred thereon to the fixing device 106.
In the first embodiment, the fixing device 106 includes a transfer roller 106a with a heating heater 106c disposed therein and a pressing roller 106b with a heating heater 106d disposed therein. The transfer roller 106a is arranged to abut against the pressing roller 106b with a specific pressing force while rotating, so that the tonner images thus transferred are pressed and heated. Then, the fixing device 106 transports the recording sheet toward the downstream side. A transportation detecting unit 107 is provided for detecting the recording sheet after the fixing device 106 fixes the toner images to the recording sheet.
In the first embodiment, the image forming apparatus 100 further includes a transportation roller pair 108, a discharge transportation path 109, a discharge roller pair 110, and a stacker 112. The transportation roller pair 108 is driven with a drive source (not shown) for transporting the recording sheet with the toner images fixed thereto to the discharge transportation path 109. The discharge roller pair 110 is driven with a drive source (not shown) for discharging the recording sheet transported through the discharge transportation path 109 to the stacker 112.
It should be noted that an X axis in
As shown in
As shown in
In the first embodiment, the sheet cassette 101 is configured such that the recording sheet is transported in the arrow direction D (a negative direction of the X axis) or a transportation direction thereof. When the sheet cassette 101 is attached to the image forming apparatus 100, the sheet placing plate 125 is arranged to presses the recording sheets, so that an uppermost sheet of the recording sheets abuts against a pickup roller 116 of the sheet supply portion 102 (refer to
In the first embodiment, a main body of the sheet cassette 101 holds the rear edge guide 124 such that the rear edge guide 124 can slide in the X axis direction. Further, the main body of the sheet cassette 101 holds the rear side guide 122 and the front side guide 123 such that the rear side guide 122 and the front side guide 123 can slide in the Y axis direction, respectively. Further, the rear side guide 122, the front side guide 123 and the front side guide 123 are arranged such that the rear side guide 122, the front side guide 123 and the front side guide 123 can be locked at desirable slide positions if necessary, respectively.
A locking mechanism of the rear side guide 122 will be explained next. As shown in
As shown in
In the first embodiment, the rear side guide 122 includes a lock member 126 on an opposite side to the guide side where the regulating surfaces 122a are formed (refer to
In the first embodiment, a small attachment gap (a play amount d) is formed between the guide surface 122b and the guide surface 122c, and the lock member 126 in the arrow direction B and the arrow direction C. It should be noted that the lock member 126 abuts against the guide surface 122b at the rear side in the state shown in
In the first embodiment, a coil spring 128 is disposed between the main body of the rear side guide 122 and the lock member 126 in a compressed state, so that the coil spring 128 urges the lock member 126 in an arrow direction G (a downward direction). Accordingly, the rack 121 disposed on the main body of the sheet cassette 101 engages with the engaging portion 126a of the lock member 126, so that the lock member 126 is locked to the main body of the sheet cassette 101. As a result, the main body of the rear side guide 122 is restricted in a movement thereof within the play amount d (the small attachment gap).
A positional relationship between the rack 121 and the engaging portion 126a of the lock member 126 will be explained next.
As shown in
In the first embodiment, the rear side guide 122 further includes the operation lever 127 capable of engaging with the lock member 126, and the operation lever 127 is supported with a rotational axis 122d thereof to be freely rotatable. The operational lever 127 includes an operation portion 127a and an application portion 127b. When the operation lever 127 is supported to be freely rotatable in an initial state shown in
In the first embodiment, when an operator operates and rotates the operation portion 127a of the operation lever 127 in an arrow direction I while the rear side guide 122 is in the initial state shown in
Accordingly, from this state, when the operator moves the rear side guide 122 to a desirable position along the arrow direction B and the arrow direction C, and releases the operation lever 127, the engaging portion 126a of the lock member 126 engages with the rack 121 once again. As a result, it is possible to lock the lock member 126 at the desirable position, and restrict the movement of the rear side guide 122 within the play amount d (the small attachment gap) at the desirable position.
In the first embodiment, the lock member 126 includes a recessed portion having an abutting inclined surface 126c on a side portion thereof on the pullout side (the arrow direction B) at a position near the engaging portion 126a. The abutting inclined surface 126c is formed to incline in the arrow direction C (the opposite direction to the arrow direction B) from below toward upward. Further, the rear side guide 122 includes an abutting portion 122e on the front side thereof at a lower portion of the guide surface 122c. The abutting portion 122e is arranged to face and be able to abut against the abutting inclined surface 126c.
In the first embodiment, as explained above, the abutting portion 122e is arranged to be able to abut against the abutting inclined surface 126c at an abutting position thereof. A maximum distance h is set between the abutting portion 122e and the abutting position of the abutting inclined surface 126c, and it is configured such that the maximum distance h becomes substantially equal to or slightly smaller than the play amount d (the small attachment gap). It should be noted that the abutting portion 122e and the abutting inclined surface 126c correspond to a movement conversion member.
In the first embodiment, it is preferable that the abutting inclined surface 126c is inclined at an inclination angle of about 40° to 45° (the inclination angle is 45° in the first embodiment). Further, it is preferable that the maximum distance h is set to be smaller than the pitch p2 of the engaging portion 126a that corresponds to the positional accuracy of the lock member 126.
An operation of the rear side guide 122 with the configuration described above will be explained next.
In the first embodiment, when the operator tries to place the recording sheets in the sheet cassette 101, first, the operator pulls out the sheet cassette 101 shown in
After the operator slides and moves the rear side guide 122 to the desirable position, when the operator releases the operation lever 127, the engaging portion 126a of the lock member 126 engages with the rack 121 once again with the urging force of the coil spring 128. As a result, it is possible to lock the lock member 126 at the desirable position, and restrict the movement of the rear side guide 122 within the play amount d (the small attachment gap) at the desirable position.
Further, after the operator slides and moves the rear side guide 122 to the desirable position, the operator places the recording sheets in a stacked state on the specific area of the sheet cassette 101 while the rear edge guide 124, the rear side guide 122, and the front side guide 123 guide the recording sheets.
After the operator places the recording sheets in the sheet cassette 101, the operator pushes the sheet cassette 101 in the insertion direction or the arrow direction C, so that the sheet cassette 101 is attached to the main body of the image forming apparatus 100 at the standard attachment position thereof. At this moment, the sheet cassette 101 abuts against a stopper (not shown), so that the further movement of the sheet cassette 101 is restricted at the standard attachment position.
In the first embodiment, when the sheet cassette 101 abuts against the stopper, the rear side guide 122 of the sheet cassette 101 receives a large force, that is, an impact upon attachment of the sheet cassette 101, in the arrow direction C through a moment of the recording sheets retained in the sheet cassette 101 in the stacked state. Accordingly, the rear side guide 122 is shifted in the arrow direction C by the play amount d (the small attachment gap) relative to the lock member 126 that is locked through the urging force of the coil spring 128. As a result, as shown in
Accordingly, when the sheet cassette 101 with the recording sheets retained therein in the stacked state is attached to the main body of the image forming apparatus 100, the rear side guide 122 receives the component force in the arrow direction C (the insertion direction) through the moment of the recording sheets and the like. With the component force, the engaging portion 126a of the lock member 126 engages with the rack 121 formed on the main body of the sheet cassette 101 with the engaging force that is increased from that generated with the urging force of the coil spring 128. As a result, it is possible to restrict the lock member 126 from being disengaged, thereby preventing the rear side guide 122 from being shifted.
As explained above, in the sheet cassette 101, the coil spring 128 generates the urging force as the initial position restriction force of the rear side guide 122 that regulates the recording sheets, so that the engaging portion 126a of the lock member 126 engages with the rack 121 formed on the main body of the sheet cassette 101 with the engaging force (the locking force). In the first embodiment, the sheet cassette 101 is configured such that it is possible to obtain the sufficient engaging force (the locking force) without setting the engaging force at an excessively high level. Accordingly, it is possible to secure the positional accuracy of the recording sheets without sacrificing the operability of the sheet cassette 101.
Second Embodiment
A second embodiment of the present invention will be explained next.
In the second embodiment, different from the sheet cassette 101 in the first embodiment shown in
As shown in
In the second embodiment, the rear side guide 222 includes a rack portion 222f at a lower portion of the sheet placing plate 125 (refer to
In the second embodiment, when the operator moves the front side guide 223 in the arrow direction C, the rack portion 223f is moved in the arrow direction C, so that the pinion gear 230 is rotated in an arrow direction M. As a result, the rack portion 222f, that is, the rear side guide 222, is moved by the same amount in the arrow direction B. Similarly, when the operator moves the front side guide 223 in the arrow direction B, the pinion gear 230 is rotated in an arrow direction L. As a result, the rear side guide 222 is moved by the same amount in the arrow direction C.
A locking mechanism of the rear side guide 122 will be explained next. As shown in
As shown in
In the second embodiment, the front side guide 223 includes a lock member 226 on an opposite side to the guide side where a regulating surface 223a is formed for regulating the front side of the recording sheet. The lock member 226 is integrally formed of an engaging portion 226a disposed at a lower portion thereof and an application surface 226b disposed at an upper portion thereof. Further, the front side guide 223 is configured to hold the lock member 226 with a guide portion including a guide surface 223b and a guide surface 223c facing oppositely each other, so that the lock member 226 can slide in the arrow direction F and the arrow direction G, that is, the vertical direction.
In the second embodiment, the small attachment gap (the play amount d) is formed between the guide surface 223b and the guide surface 223c, and the lock member 226 in the arrow direction B and the arrow direction C. Further, a coil spring 228 is disposed between the main body of the front side guide 223 and the lock member 226 in a compressed state, so that the coil spring 228 urges the lock member 226 in the arrow direction G (the downward direction). Accordingly, the rack 121 disposed on the main body of the sheet cassette 201 engages with the engaging portion 226a of the lock member 226, so that the lock member 226 is locked to the main body of the sheet cassette 201. As a result, the main body of the front side guide 223 is restricted in a movement thereof within the play amount d (the small attachment gap).
In the second embodiment, the relationship between the rack 121 and the engaging portion 226a of the lock member 226 is similar to that between the rack 121 and the engaging portion 126a of the lock member 126 in the first embodiment explained with reference to
In the second embodiment, the front side guide 223 further includes the operation lever 227 capable of engaging with the lock member 226, and the operation lever 227 is supported with a rotational axis 223d thereof to be freely rotatable. The operational lever 227 includes an operation portion 227a and an application portion 227b. When the operation lever 227 is supported to be freely rotatable in an initial state shown in
In the second embodiment, when the operator operates and rotates the operation portion 227a of the operation lever 227 in an arrow direction Q while the front side guide 223 is in the initial state shown in
Accordingly, from this state, when the operator moves the front side guide 223 to a desirable position along the arrow direction B and the arrow direction C, and releases the operation lever 227, the engaging portion 226a of the lock member 226 engages with the rack 121 once again. As a result, it is possible to lock the lock member 226 at the desirable position, and restrict the movement of the front side guide 223 within the play amount d (the small attachment gap) at the desirable position. At this moment, as explained above, together with the movement of the front side guide 223 in the Y axis direction, the rear side guide 222 is moved by the same amount in the opposite direction.
In the second embodiment, as shown in
In the second embodiment, as explained above, the abutting portion 223e is arranged to be able to abut against the abutting inclined surface 226c at an abutting position thereof. The maximum distance h is set between the abutting portion 223e and the abutting position of the abutting inclined surface 226c, and it is configured such that the maximum distance h becomes substantially equal to or slightly smaller than the play amount d (the small attachment gap).
In the second embodiment, it is preferable that the abutting inclined surface 226c is inclined at an inclination angle of about 40° to 45° (the inclination angle is 45° in the second embodiment). Further, it is preferable that the maximum distance h is set to be smaller than the pitch p2 of the engaging portion 226a that corresponds to the positional accuracy of the lock member 226.
An operation of the front side guide 223 with the configuration described above will be explained next.
In the second embodiment, when the operator tries to place the recording sheets in the sheet cassette 201, first, the operator pulls out the sheet cassette 201 shown in
After the operator slides and moves the front side guide 223 to the desirable position, when the operator releases the operation lever 227, the engaging portion 226a of the lock member 226 engages with the rack 121 once again with the urging force of the coil spring 228. As a result, it is possible to lock the lock member 226 at the desirable position, and restrict the movement of the front side guide 223 within the play amount d (the small attachment gap) at the desirable position.
Further, after the operator slides and moves the front side guide 223 to the desirable position, the operator places the recording sheets in a stacked state on the specific area of the sheet cassette 201 while the rear edge guide 124, the rear side guide 222, and the front side guide 223 guide the recording sheets.
After the operator places the recording sheets in the sheet cassette 201, the operator pushes the sheet cassette 201 in the insertion direction or the arrow direction C, so that the sheet cassette 201 is attached to the main body of the image forming apparatus 100 at the standard attachment position thereof. At this moment, the sheet cassette 201 abuts against a stopper (not shown), so that the further movement of the sheet cassette 201 is restricted at the standard attachment position.
In the second embodiment, when the sheet cassette 201 abuts against the stopper, the rear side guide 222 of the sheet cassette 201 receives a large force, that is, an impact upon attachment of the sheet cassette 201, in the arrow direction C through a moment of the recording sheets retained in the sheet cassette 201 in the stacked state. As a result, the rear side guide 222 tries to move in the arrow direction. Further, the front side guide 223 receives the large force in the arrow direction B through a force transmitted through the link mechanism shown in
At this moment, the front side guide 223 is shifted in the arrow direction B by the play amount d (the small attachment gap) relative to the lock member 226 that is locked through the urging force of the coil spring 228. As a result, the abutting portion 223e of the front side guide 223 abuts against and pushes the abutting inclined surface 226c of the lock member 226. At the moment, a component force of the pressure is generated downwardly in the arrow direction G according to the inclination angle of the abutting inclined surface 226c, so that the lock member 226 is pushed against the bottom surface 201a of the sheet cassette 201.
Accordingly, when the sheet cassette 201 with the recording sheets retained therein in the stacked state is attached to the main body of the image forming apparatus 100, the front side guide 223 receives the component force in the arrow direction B (the pullout direction) through the moment of the recording sheets and the like. With the component force, the engaging portion 226a of the lock member 226 engages with the rack 121 formed on the main body of the sheet cassette 201 with the engaging force that is increased from that generated with the urging force of the coil spring 228. As a result, it is possible to restrict the lock member 226 from being disengaged, thereby preventing the front side guide 223 and the rear side guide 222 that are moved together through the link mechanism from being shifted.
As explained above, in the sheet cassette 201, the coil spring 228 generates the urging force as the initial position restriction force of the front side guide 223 that regulates the recording sheets, so that the engaging portion 226a of the lock member 226 engages with the rack 121 formed on the main body of the sheet cassette 201 with the engaging force (the locking force). In the second embodiment, the sheet cassette 101 is configured such that it is possible to obtain the sufficient engaging force (the locking force) without setting the engaging force at an excessively high level. Accordingly, it is possible to secure the positional accuracy of the recording sheets without sacrificing the operability of the sheet cassette 201. Further, the operation lever 227 of the front side guide 223 is disposed on the front side of the image forming apparatus 100. Accordingly, it is possible to further improve the operability of the sheet cassette 201.
In the first embodiment and the second embodiment described above, the present invention is applied to the electro-photographic printer, and is not limited thereto. The present invention may be applicable to an MFP (Multi Function Printer), a facsimile, a copier, and the like.
The disclosure of Japanese Patent Application No. 2013-151737, filed on Jul. 22, 2013, is incorporated in the application.
While the invention has been explained with reference to the specific embodiments of the invention, the explanation is illustrative and the invention is limited only by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-151737 | Jul 2013 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 5611528 | Nakamura et al. | Mar 1997 | A |
| 8128084 | Kitayama | Mar 2012 | B2 |
| Number | Date | Country |
|---|---|---|
| H06-82053 | Nov 1994 | JP |
| H07-206170 | Aug 1995 | JP |
| H11-139573 | May 1999 | JP |
| 2000-136033 | May 2000 | JP |
| 2006-008351 | Jan 2006 | JP |
| 2010-052858 | Mar 2010 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20150023710 A1 | Jan 2015 | US |
