JP6264653B2 - Sheet placing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet placing apparatus provided in an image forming apparatus such as a printer, a facsimile machine, and a copying machine, and an image forming apparatus provided with the sheet placing apparatus.

  In Japanese Patent Laid-Open No. 2004-133867, a sheet mounting unit that transports a sheet such as a sheet set on a manual feed table, which is a sheet placement unit that can be opened and closed with respect to the image forming apparatus main body, from the manual feed table to the image forming unit by a sheet conveying unit. A placement device is disclosed.

  This sheet stacking device has a length in the conveyance direction of the maximum size sheet that faces the sheet when a sheet having a length of more than half of the maximum size sheet is set on the manual feed table. When a sheet having a length less than half of the length is set on the manual feed table, a sheet length detecting means for detecting the length of the sheet is provided at a position on the manual feed table that does not face the sheet.

  The sheet length detection means includes a paper detection unit that protrudes forward and backward on the placement surface of the manual feed table, and a retraction type optical sensor that detects whether or not the paper detection unit has retreated below the placement surface. And a detection unit.

  The sheet length detection means transmits the sheet detection unit that has popped out from the placement surface of the manual feed table by being pushed by the sheet and stored in the manual feed table when the sheet is set on the placement surface. The type optical sensor is shielded or transmitted to detect a sheet having a specific length or more.

  Thereby, by using the detection result of the sheet length detection means, it is possible to narrow down whether the size of the sheet set on the manual feed table is a predetermined standard size. Then, it is possible to set the image condition based on the size information of the sheets thus narrowed down.

  Further, the sheet placement device described in Patent Document 1 is provided with a sheet presence / absence detection unit that detects the presence / absence of a sheet on the manual feed table. When feeding a sheet from the manual feed table, when the sheet presence / absence detecting means detects that there is a sheet on the manual feed table, the sheet feeding means feeds the sheets one by one, and the image provided in the image forming apparatus It is conveyed toward the forming unit.

  In general, in an image forming apparatus, in order to save energy, when an image is not formed for a certain period of time, the image forming apparatus shifts from a normal operation mode in which an image can be formed to an energy saving mode (sleep mode) that saves power consumption. To do.

  On the other hand, since it takes time to return from the energy saving mode to the normal operation mode, in order to reduce the waiting time for the user, the return operation to the normal operation mode can be started when the manual feeder is opened. Installation of an open / close detection means for detecting opening / closing of the manual feed table is desired.

  However, in addition to the sheet length detection means and the sheet presence / absence detection means, if a separate opening / closing detection means is additionally provided for detecting the opening / closing of the manual feed table, there arises a problem that the cost increases.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to place a sheet on which sheet length detection, sheet presence / absence detection, and sheet placement unit opening / closing detection can be performed while reducing costs. An image forming apparatus including the apparatus and the sheet placing apparatus is provided.

  In order to achieve the above object, the invention according to claim 1 is a sheet mounting portion that can be opened and closed with respect to the apparatus main body and has a mounting surface on which a sheet can be mounted, and mounting of the sheet mounting portion. A sheet length detecting means for detecting whether or not a surface facing the placement surface of the sheet is in contact with or in proximity at a predetermined position in the sheet conveying direction on the surface; In the sheet placement apparatus including a sheet presence / absence detection unit that detects whether or not a sheet is present in the placement unit, the sheet length detection unit protrudes on the placement surface of the sheet placement unit so as to advance and retreat. In the state where the sheet placement unit is closed with respect to the apparatus main body, the projection unit is mounted. It is configured to take the position retracted under the placement surface, When the sheet detects that the protruding portion has retreated below the placement surface, and the sheet presence / absence detection means detects that there is no sheet, it is determined that the sheet placement portion is closed with respect to the apparatus main body. It has the judgment means to do.

  As described above, according to the present invention, there is an excellent effect that sheet length detection, sheet presence / absence detection, and sheet placement portion opening / closing detection can be performed while reducing costs.

FIG. 3 is a perspective view of a paper stacking apparatus according to Configuration Example 1. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment. 4A and 4B are diagrams illustrating a manual feed tray according to Configuration Example 1. FIG. Schematic of a paper length detection device. FIG. 3 is an enlarged perspective view of a manual sheet feeder provided in the sheet stacking apparatus. FIG. 3 is a perspective view illustrating a schematic configuration of a sheet presence / absence detection device. The perspective view which shows schematic structure of a cover. The figure which showed the state just before closing a manual feed tray with respect to a cover. The figure which showed the state which closed the manual feed tray with respect to the cover. FIG. 6 is a perspective view illustrating an embodiment of a sheet placing device provided in an image forming apparatus according to Configuration Example 2. FIG. 6 is a diagram illustrating a sheet length detection device according to Configuration Example 2.

  An embodiment in which the present invention is applied to an image forming apparatus will be described. FIG. 2 is a schematic configuration diagram of the image forming apparatus according to the present embodiment.

  As shown in FIG. 2, the image forming apparatus 1 includes an image forming unit 100 disposed substantially at the center of the apparatus main body, a paper feeding unit 203 disposed below the image forming unit 100, and the image forming apparatus 1. The operation unit 13 and the like for the operator to operate when performing image formation are provided.

  The image reading unit 50 as an image reading apparatus includes a scanner 150 fixed on the image forming unit 100 and an automatic document feeder (hereinafter referred to as “ADF”) 51 supported by the scanner 150. Yes.

  Two paper feed cassettes 109 that can be attached to and detached from the apparatus main body are mounted on the paper feed unit 203, and each of them accommodates paper P of a different paper type.

  The paper P is fed by a paper feed roller 111 from a paper feed cassette 109 to a conveyance path 110 extending in a substantially vertical (vertical) direction from the paper feed unit 203 to the paper discharge unit 11. Next, the image is transported through the transport path 110 by the transport roller 112, subjected to image formation and fixing processing by the image forming unit 100, and then discharged to the paper discharge unit 11 by the paper discharge roller pair 5.

  The image forming unit 100 is provided with a photoconductor 115 as an image carrier that is driven to rotate counterclockwise as indicated by an arrow in the drawing, an optical writing device 116 that forms an electrostatic latent image on the photoconductor 115, and the like. ing.

  Further, a charging device 117 as a charging device that uniformly charges the photoconductor 115 is disposed around the photoconductor 115 in the counterclockwise direction of the photoconductor 115.

  Further, a developing device 118 that visualizes an electrostatic latent image on the photosensitive member 115 by attaching toner, and a transfer roller 119 that transfers the toner image formed by the developing device 118 to the conveyed paper P are arranged. It is installed.

  Further, a cleaning unit 120 for removing the toner remaining on the photoconductor 115 after the transfer and cleaning the photoconductor 115 is also provided.

  A fixing device 121 is provided between the transfer roller 119 and the paper discharge unit 11 to heat and press the toner image transferred onto the paper P by the transfer roller 119 and fix the toner image on the paper P.

  The optical writing device 116 exposes the surface of the photoconductor 115 with laser light based on image data from the scanner 150 or image information input from a personal computer or the like, and performs optical writing to perform the optical writing. An electrostatic latent image is formed thereon.

  The paper P is selectively fed by one of the paper feed rollers 111 of the upper and lower paper feed cassettes 109, and is transported in the transport path 110 by the transport roller 112.

  Furthermore, after the conveyance of the paper P is temporarily stopped by the registration roller pair 123 provided upstream of the transfer roller 119 in the paper conveyance direction, the nip portion between the transfer roller 119 and the photoconductor 115 at a predetermined timing. Is fed by a registration roller pair 123. A toner image is transferred from the photosensitive member 115 to the paper P at the nip portion.

  The paper P on which the toner image has been transferred in the two-up section is conveyed to the fixing device 121, where the toner image is fixed on the paper P by heat and pressure by the fixing device 121, and the paper discharge section 11 provided outside the apparatus. The paper is discharged by a pair of paper discharge rollers 5.

  In the image forming apparatus 1 of the present embodiment, double-sided printing is also possible. In this case, after the toner image is fixed on the front surface of the paper P, the conveyance path is switched by the branching claw 7 to the reverse roller pair 6 side. The paper P is conveyed.

  The reversing roller pair 6 discharges the paper P to the reversing tray 12 halfway and then reversely rotates to feed the paper P to the double-sided conveyance path 8 side. The paper P sent to the double-sided conveyance path 8 is conveyed again to the position of the registration roller pair 123 with the front and back sides determined.

  Then, after transferring the toner image from the photosensitive member 115 to the back surface of the paper P sent to the two-up portion from the registration roller pair 123, the toner image is fixed on the paper P by the fixing device 121, and the paper discharge roller The paper is discharged to the paper discharge unit 11 by the pair 5.

  An image reading unit 50 including a scanner 150 fixed on the image forming unit 100 and an ADF 51 fixed on the image forming unit 100 includes two fixed reading units and a moving reading unit 152 described later.

  The movable reading unit 152 is disposed directly below the second contact glass 155 fixed to the upper wall of the casing of the scanner 150 so as to come into contact with the document MS, and shows an optical system including a light source, a reflection mirror, and the like. It can be moved in the left-right direction.

  Then, in the process of moving the optical system from the left side to the right side in the figure, after the light emitted from the light source is reflected by the lower surface of the document MS placed on the second contact glass 155, a plurality of reflecting mirrors are Then, the light is received by the image reading sensor 153 fixed to the scanner 150.

  On the other hand, the image reading unit 50 includes, as fixed reading units, a first fixed reading unit 151 disposed in the scanner 150 and a second fixed reading unit 95 described later disposed in the ADF 51. .

  A first fixed reading unit 151 including a light source, a reflection mirror, an image reading sensor such as a CCD, and the like is disposed directly below a first contact glass 154 fixed to the upper wall of the casing of the scanner 150 so as to contact the document MS. ing.

  Then, when the document MS conveyed by the ADF 51 passes over the first contact glass 154, image reading is performed via a plurality of reflecting mirrors while sequentially reflecting the light emitted from the light source on the first surface of the document MS. The sensor 153 receives light.

  Accordingly, the first surface of the document MS is scanned without moving the optical system including the light source and the reflection mirror. The second fixed reading unit 95 scans the second surface of the document MS after passing through the first fixed reading unit 151.

  An ADF 51 disposed on the scanner 150 includes a document placing table 53 for placing a document MS before reading on a main body cover 52, a document transporting unit 54 for transporting a document MS as a sheet material, and a reading. A document stacking table 55 for stacking the subsequent document MS is held.

  Further, the image forming apparatus 1 of the present embodiment is provided with a cover 14 that can be opened to the apparatus main body so that the inside of the double-sided conveyance path 8 can be exposed to the outside when a paper jam occurs in the double-sided conveyance path 8. It has been. As shown in FIG. 2, the cover 14 is provided with a manual paper feeder 15 and a manual tray 701 so as to feed more types of paper P.

  The manual feed tray 701 can be opened and closed with respect to the cover 14, and FIG. 2 shows a state in which the manual feed tray 701 is opened with respect to the cover 14. The paper P stacked on the open manual feed tray 701 in this way is conveyed toward the image forming apparatus 1 by the manual paper feed device 15. In the present embodiment, at least the cover 14 and the manual feed tray 701 constitute a sheet placing device that is a sheet placing device.

  Further, in the image forming apparatus 1 of the present embodiment, in order to save energy, a power consumption mode that saves power consumption by reducing power supply to the fixing device 121 or the like when image formation is not performed for a certain period of time. The mode is shifted to the sleep mode.

  On the other hand, in the return operation from the sleep mode to the normal operation mode in which the image can be formed, it is necessary to raise the temperature of the fixing device to the fixing possible temperature, and it takes time to return from the sleep mode to the normal operation mode. Take it. Therefore, in the image forming apparatus 1 according to the present embodiment, when the manual feed tray 701 is opened with respect to the cover 14, the return operation from the sleep mode to the normal operation mode is started to reduce the waiting time of the user.

[Configuration example 1]
FIG. 1 is a perspective view of a paper stacking apparatus according to Configuration Example 1. FIG. FIG. 3 is a diagram illustrating the manual feed tray 701 according to the configuration example 1. The manual feed tray body 701b of the manual feed tray 701 is set to have a length in the paper transport direction that is approximately the same as the length of the A4 size or B5 size paper P that is frequently used from the viewpoint of space saving and improved operability.

  Various sizes of paper P such as A4 size and B5 size are placed on the manual feed tray 701. For this reason, the image forming apparatus 1 needs to recognize the size of the paper P placed on the manual feed tray 701 before printing by the image forming apparatus 1.

  The manual feed tray body 701b is provided with a pair of side fences 704 that are slidable in the paper width direction. The pair of side fences 704 are aligned with the width direction of the paper P placed on the manual feed tray 701.

  The manual feed tray 701 is provided with a variable resistor and a rotary switch (not shown) that operate in conjunction with the side fence 704. By using this, the paper length in the paper width direction placed on the manual feed tray 701 is used. Is detected.

  However, for example, the paper size may not be specified only by the width of the paper P placed on the manual feed tray 701, such as a horizontal set of A4 size paper P and a vertical set of A3 size paper P. .

  Therefore, the paper length detection device 401 provided in the manual feed tray body 701b detects whether or not the length in the paper transport direction of the paper P placed on the manual feed tray 701 is a certain length or more. Then, the paper size is specified by the two pieces of information of the width of the paper P and the length in the transport direction.

  FIG. 4 is a schematic diagram of the paper length detection device 401 according to the first configuration example. In FIG. 4, the paper placement cover 701a (see FIG. 3), which is a component of the manual feed tray body 701b, is invisible.

  The paper length detection device 401 includes a rotation shaft 401c that is rotatably supported with respect to the manual feed tray 701, a paper detection unit 401a provided at one end of the rotation shaft 401c in the axial direction, and a shaft of the rotation shaft 401c. And a light shielding portion 401b provided at the center in the direction. In addition, the optical sensor 402 includes a light-emitting unit 402a and a light-receiving unit 402b that sandwich the light-shielding unit 401b.

  The paper detection unit 401a is installed so as to protrude upward from the placement surface of the manual feed tray body 701b. If the length of the paper P placed on the manual feed tray 701 in the transport direction is a length that reaches the paper detection unit 401a of the paper length detection device 401, the paper detection unit 401a uses the paper to manually feed the tray 701. It is pushed toward the inside.

  When the paper detection unit 401 a is pushed in this way, the rotation shaft 401 c rotates, and the light shielding unit 401 b also rotates with the rotation, and the light shielding unit 401 b shields the light receiving unit 402 b of the transmissive optical sensor 402. Translucent. This makes it possible to detect that the paper P placed on the manual feed tray 701 is longer than a certain length.

  Note that a reflection type optical sensor is used instead of a transmission type optical sensor to detect whether or not the sheet P on the manual feed tray 701 is longer than a certain length based on the presence or absence of reflected light from the light shielding unit 401b. It does not matter if it is configured.

FIG. 5 is an enlarged perspective view of the manual sheet feeder 15 provided in the sheet stacking apparatus.
The manual paper feeder 15 is provided with a paper presence / absence detector 17 that detects the presence or absence of the paper P on the manual tray 701.

FIG. 6 is a perspective view illustrating a schematic configuration of the sheet presence / absence detection device 17.
The sheet presence / absence detection device 17 includes a rotation shaft 17b that is rotatably supported with respect to a side plate, a sheet contact portion 17a provided at one end of the rotation shaft 17b in the axial direction, and an axial center of the rotation shaft 17b. And a light-shielding portion 17c provided on the surface. Moreover, it has the transmissive | pervious optical sensor 18 in which the light emission part 18a and the light-receiving part 18b were provided so that the light-shielding part 17c might be pinched | interposed.

  The sheet contact portion 17 a is installed so as to jump out to the sheet conveyance path of the manual sheet feeder 15. Then, when the paper P is placed on the manual feed tray 701, the paper contact portion 17a is pushed by the leading end of the paper P, so that the paper contact portion 17a rotates in the direction of the arrow around the rotation shaft 17b. Move.

  Along with this rotation, the light shielding portion 17c also rotates in the direction of the arrow in the figure around the rotation shaft 17b, and the presence or absence of the paper P is detected by shielding or transmitting the light receiving portion 18b of the transmissive optical sensor 18.

  Note that a configuration in which the presence or absence of the paper P on the manual feed tray 701 may be detected based on the presence or absence of the reflected light from the light shielding portion 17c by using a reflective optical sensor instead of the transmissive optical sensor.

FIG. 7 is a perspective view showing a schematic configuration of the cover 14.
The cover 14 is provided with a paper detection unit 401a at a position facing the paper detection unit 401a of the paper length detection device 401 provided on the manual feed tray 701 when the manual feed tray 701 is closed with respect to the cover 14. A pushing-in portion 14a having a protruding shape to be pushed in is provided.

  FIG. 8 is a view showing a state immediately before the manual feed tray 701 is closed with respect to the cover 14. In this state, since the paper detection unit 401a of the paper length detection device 401 is not pushed toward the inside of the manual feed tray 701, the paper length detection device 401 detects that the paper P is less than a certain length. It is in the state.

  At this time, since the paper P is not placed on the manual feed tray 701, the above-described paper presence / absence detecting device 17 detects that the paper P is not present.

  FIG. 9 is a diagram illustrating a state where the manual feed tray 701 is closed with respect to the cover 14. In this state, the paper detection unit 401 a of the paper length detection device 401 is pushed into the manual feed tray 701 by the push-in unit 14 a provided on the cover 14, and the paper P is fixed by the paper length detection device 401. It is in a state where it is detected that it is more than this.

  At this time, since the paper P is not placed on the manual feed tray 701, the above-described paper presence / absence detecting device 17 detects that the paper P is not present.

  Table 1 shows the open / close state of the manual feed tray 701 with respect to the cover 14 based on the combination of the detection result of the paper presence / absence detection device 17 and the detection result of the paper length detection device 401.

  When the detection result of the paper presence / absence detection device 17 is “none” and the detection result of the paper length detection device 401 is “less than a certain value”, control is performed so that the manual feed tray 701 is open with respect to the cover 14. Judge by department.

  Further, when the detection result of the paper presence / absence detection device 17 is “None” and the detection result of the paper length detection device 401 is “a certain level”, the manual feed tray 701 is closed with respect to the cover 14. And determined by the control unit.

  As a result, it is possible to perform sheet length detection, sheet presence / absence detection, and manual tray open / close detection while reducing costs, since there is no need to separately provide a dedicated detection means for detecting opening / closing of the manual feed tray 701. it can.

  In this configuration example, when the manual feed tray 701 is opened based on the determination result of the control unit based on the detection results of the paper presence / absence detection device 17 and the paper length detection device 401, the normal operation mode is changed from the energy saving mode. It is possible to start the return operation to.

  Accordingly, when the control unit determines that the manual feed tray 701 is opened with respect to the cover 14, the image forming unit 100, the fixing device 121, and the like are brought into an image formable state, thereby reducing the time for the user to wait until the image formation starts. can do.

  In addition, since the paper presence / absence detection device 17 is provided in the manual paper feeding device 15, when the paper presence / absence detection device 17 detects that there is paper, the paper placed on the manual tray 701 is manually fed. It will be located at the position of the device 15. Therefore, the paper on the manual feed tray 701 can be reliably fed by the manual feed device 15.

  Further, since it is not necessary to separately provide a dedicated detection means for detecting that the sheet is located at the position of the manual sheet feeder 15, the cost can be reduced accordingly.

[Configuration example 2]
FIG. 10 is a perspective view of the paper stacking apparatus according to Configuration Example 2. Note that the basic configuration of the paper stacking apparatus of Configuration Example 2 is substantially the same as that of the paper stacking apparatus of Configuration Example 1 described above, and a description thereof will be omitted.

  FIG. 11 is a diagram illustrating a paper length detection device 702 provided in the manual feed tray 701 according to the configuration example 2.

  The paper length detection device 702 includes a first paper detection unit 702a and a second paper that are provided so as to protrude above the placement surface on which the paper P of the paper placement cover 701a of the manual feed tray body 701b is placed. A detection unit 702b, a rotation shaft 702c, and the like are included. The first paper detection unit 702a and the second paper detection unit 702b are erected on the circumferential surfaces at both ends in the axial direction of the rotation shaft 702c.

  When the paper P is placed on the manual feed tray 701, either the first paper detection unit 702a or the second paper detection unit 702b is pushed by the paper P and stored in the manual feed tray main body. At the same time, the other paper detection unit is housed in the manual feed tray body.

  Further, a light shielding portion 702d is provided upright on the peripheral surface in the vicinity of the second paper detection unit 702b between the first paper detection unit 702a and the second paper detection unit 702b in the axial direction of the rotation shaft 702c.

  Then, the light shielding unit 702d shields or transmits the light receiving unit 402b of the transmissive optical sensor 402, so that it can be detected whether or not the paper P on the manual feed tray 701 is longer than a certain length.

  In addition, it is also possible to use a reflection type sensor instead of a transmission type sensor to detect whether or not the paper P on the manual feed tray 701 is longer than a certain length based on the presence or absence of reflected light from the light shielding unit 702d. It doesn't matter.

  Further, the first sheet detection unit 702a and the second sheet detection unit 702b are provided with inclined portions 702e, respectively. As a result, when the paper P is placed on the manual feed tray body 701b, the load is reduced regardless of whether the paper P is placed in the direction perpendicular to the parallel direction with respect to the paper transport direction, thereby reducing the load. The sheet P can be pushed down the sheet 702a or the second sheet detection unit 702b.

  As shown in FIG. 10, the first paper detection unit 702 a is disposed on the cover 14 at a position facing the first paper detection unit 702 a of the paper length detection device 702 with the manual feed tray 701 closed with respect to the cover 14. A projection-shaped pushing portion 14a is provided to push in.

  When the manual feed tray 701 is closed with respect to the cover 14, the first paper detection unit 702 a is pushed into the manual feed tray 701 by the push-in unit 14 a provided on the cover 14.

  As a result, the rotation shaft 702c of the paper length detection device 702 rotates, and the light shielding unit 702d also rotates with the rotation, and the light shielding unit 702d shields or transmits the light receiving unit 402b of the transmission optical sensor 402. . As a result, the paper length detection device 702 detects that the paper P is longer than a certain length.

  Further, when the manual feed tray 701 is closed with respect to the cover 14, the paper P is not placed on the manual feed tray 701, so that the paper presence / absence detection device 17 detects that there is no paper P.

  On the other hand, in a state immediately before the manual feed tray 701 is closed with respect to the cover 14, the first paper detection unit 702 a is not pushed toward the inside of the manual feed tray 701, so that the paper P is fixed by the paper length detection device 702. It is in a state where it is detected that it is less than the length.

  Further, when the manual feed tray 701 is to be closed with respect to the cover 14, since the paper P is not placed on the manual feed tray 701, the paper presence / absence detection device 17 detects that there is no paper P. .

  Therefore, when the detection result of the sheet presence / absence detection device 17 is “none” and the detection result of the sheet length detection device 702 is “a certain level”, the manual feed tray 701 is closed with respect to the cover 14. Judgment is made by the control unit.

  On the other hand, when the detection result of the paper presence / absence detection device 17 is “none” and the detection result of the paper length detection device 702 is “less than a certain value”, the manual feed tray 701 is open with respect to the cover 14. And determined by the control unit.

  Thereby, the cost of the apparatus can be reduced because it is not necessary to separately provide a dedicated detection means for detecting the open / closed state of the manual feed tray 701 with respect to the cover 14.

  Further, when the image forming apparatus 1 detects that the manual feed tray 701 is opened with respect to the cover 14, an operation method for feeding the paper P from the manual feed tray 701 is displayed on a display provided in the operation unit 13. Accordingly, when paper is fed from the manual feed tray 701, it is possible to simplify paper passing settings for various paper types and paper sizes that can be fed from the manual feed tray performed by an operator.

  Further, when the manual feed tray 701 is opened, the return operation from the energy saving mode to the normal operation mode can be started. As a result, when the state in which the manual feed tray 701 is opened with respect to the cover 14 is detected, the image forming unit 100, the fixing device 121, and the like are brought into an image formable state, thereby shortening the time that the user waits for the start of image formation. Can do.

  In this configuration example, the detection state of the paper length detection device 702 is switched depending on whether or not the first paper detection unit 702a is pushed in by the protrusion-shaped push-in part 14a provided on the cover 14. It is not limited.

  For example, even if the pushing portion 14a is not provided in the cover 14, the weight balance may be such that the light shielding state and the light transmitting state by the light shielding portion 702d are switched while the manual feed tray 701 is closed with respect to the cover 14. .

  Further, when the paper length detection device 702 is configured by a reflective optical sensor, the detection state can be switched by detecting the reflected light of the push-in portion 14a.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
A sheet placement unit such as a manual feed tray 701 that can be opened and closed with respect to the apparatus main body and has a placement surface on which a sheet such as paper P can be placed, and a sheet conveyance direction on the placement surface of the sheet placement unit A sheet length detecting unit such as a sheet length detecting device 702 that detects whether or not a surface facing the placement surface of the sheet is in contact with or close to the sheet at a predetermined position; In a sheet placement device such as a paper placement device that includes a sheet presence / absence detection unit that detects whether or not a sheet is present in the placement unit, the sheet length detection unit advances and retreats on the placement surface of the sheet placement unit. The apparatus main body has a protruding portion such as a first sheet detecting portion 702a protruding so as to be able to protrude, and a retraction detecting portion such as a transmissive optical sensor 402 for detecting whether the protruding portion has retreated below the placement surface. On the other hand, in a state where the sheet placement portion is closed, The exit portion is configured to take a position retracted below the placement surface, the retract detection portion detects that the protrusion has retracted below the placement surface, and the sheet presence / absence detection means detects that there is no sheet. In this case, there is a determination unit that determines that the sheet placement unit is closed with respect to the apparatus main body.
In (Aspect A), as described in the above embodiment, based on the detection results of the sheet length detection unit and the sheet presence / absence detection unit, the determination unit determines that the sheet placement unit is closed with respect to the apparatus main body. Judgment. Thus, in order for the determination means to determine that the sheet placement portion is closed with respect to the apparatus main body, it is necessary to separately provide a dedicated detection means for detecting the open / closed state of the sheet placement portion with respect to the apparatus main body. No. Therefore, sheet length detection, sheet presence / absence detection, and sheet placement portion opening / closing detection can be performed while reducing costs.
(Aspect B)
In (Aspect A), a sheet conveying unit that conveys a sheet placed on the sheet placing unit to a predetermined conveying destination via a predetermined conveying path is provided, and the sheet presence / absence detecting unit includes: It is provided in the sheet conveying unit. According to this, when the sheet presence / absence detecting unit detects that there is a sheet, the sheet placed on the sheet placement unit is positioned at the sheet conveyance unit, so the sheet conveyance unit reliably conveys the sheet. can do. In addition, since it is not necessary to separately provide a dedicated detection means for detecting the position of the sheet in the sheet conveying unit, the cost can be reduced accordingly.
(Aspect C)
In (Aspect A) or (Aspect B), the protruding portion is provided on a rotation shaft that is rotatably supported with respect to the sheet placement portion, and the placement surface described above by rotating the rotation shaft. The retraction detection unit has a transmissive optical sensor, and a light shielding unit that shields or transmits light from the transmissive optical sensor is provided on the rotation shaft. According to this, as described in the above embodiment, the sheet placed on the sheet placing table is fixed by the light-shielding portion shielding or transmitting the transmission optical sensor by pushing the protruding portion. It can be detected that it is longer than the length.
(Aspect D)
In (Aspect A), (Aspect B), or (Aspect C), a position that is detected by the retraction detection unit and a position that is not detected in the opened state and the closed state of the sheet placement unit with respect to the apparatus main body. The weight balance is displaceable between the two. According to this, as described in the above-described embodiment, it is possible to detect that the protruding portion has been retracted below the placement surface by the retraction detection unit in a state where the sheet placement unit is closed with respect to the apparatus main body. .
(Aspect E)
In (Aspect A), (Aspect B), or (Aspect C), when the sheet placement portion is closed with respect to the apparatus main body, the protrusion is placed at a position facing the protrusion of the apparatus main body. A pressing part is provided to be pushed down below the placement surface. According to this, as described in the above-described embodiment, it is possible to detect that the protruding portion has been retracted below the placement surface by the retraction detection unit in a state where the sheet placement unit is closed with respect to the apparatus main body. .
(Aspect F)
In (Aspect A), (Aspect B), (Aspect C), (Aspect D) or (Aspect E), the sheet presence / absence detection means adopts a configuration having a paper presence / absence detection filler and a transmissive optical sensor. Can do.
(Aspect G)
In (Aspect A), (Aspect B), (Aspect C), (Aspect D), or (Aspect E), the sheet presence / absence detection unit may employ a configuration having a reflective optical sensor.
(Aspect H)
In the image forming apparatus in which the sheet stacked on the sheet stacking device is sent to the image forming unit by the sheet conveying unit to form an image on the sheet, the above-described sheet stacking device includes (Aspect A), (Aspect B), (Aspect The sheet placing device of C), (Aspect D), (Aspect E), (Aspect F) or (Aspect G) was used. According to this, as described in the above embodiment, it is possible to perform sheet length detection, sheet presence / absence detection, and sheet placement portion opening / closing detection while suppressing an increase in cost. In addition, based on the detection result of the sheet placement unit opening / closing detection, the user waiting time can be shortened by starting the return operation from the energy saving mode to the normal operation mode when the sheet placement unit is opened. .
(Aspect I)
(Aspect H) includes a display unit for displaying predetermined information, and when the determination unit determines that the sheet mounting unit is not closed with respect to the apparatus main body, the sheet mounting unit To display the operation method of sheet conveyance by the sheet conveying means on the display unit. According to this, as described in the above embodiment, when performing sheet conveyance from the sheet loading unit, the setting of various types and sizes of various sheets that can be conveyed from the sheet loading unit performed by the operator is simplified. Can be
(Aspect J)
In (Aspect H) or (Aspect I), when the determination unit determines that the sheet placement unit is not closed with respect to the apparatus main body, the image formation unit is shifted to an image formation preparation state. According to this, as described in the above embodiment, it is possible to reduce the time that the operator waits until the start of image formation.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 5 Paper discharge roller pair 6 Reverse roller pair 7 Branch claw 8 Double-sided conveyance path 11 Paper discharge part 12 Reverse tray 13 Operation part 14 Cover 14a Push-in part 15 Manual paper feed apparatus 17 Paper presence detection apparatus 17a Paper contact part 17b Rotating shaft 17c Light-shielding part 18 Transmission type optical sensor 18a Light-emitting part 18b Light-receiving part 50 Image reading unit 52 Main body cover 53 Document placing table 54 Document conveying unit 55 Document stacking table 95 Second fixed reading unit 100 Image forming unit 109 Paper feeding cassette DESCRIPTION OF SYMBOLS 110 Conveying path 111 Paper feeding roller 112 Conveying roller 115 Photoconductor 116 Optical writing device 117 Charging device 118 Developing device 119 Transfer roller 120 Cleaning unit 121 Fixing device 123 Registration roller pair 150 Scanner 151 First fixed reading unit 152 Moving reading unit 153 Image Reading sensor 154 First contact glass 155 Second contact glass 203 Paper feed unit 401 Paper length detection device 401a Paper detection unit 401b Light blocking unit 401c Rotating shaft 402 Transmission type optical sensor 402a Light emitting unit 402b Light receiving unit 701 Manual tray 701a Paper placement Cover 701b Manual feed tray body 702 Paper length detection device 702a First paper detection unit 702b Second paper detection unit 702c Rotating shaft 702d Light shielding unit 702e Inclined unit 704 Side fence

JP 2011-225293 A

Claims (10)

A sheet mounting portion that can be opened and closed with respect to the apparatus main body and has a mounting surface on which a sheet can be mounted;
The sheet length for detecting the sheet length by detecting whether or not a surface facing the above-described placement surface of the sheet is in contact with or in proximity at a predetermined position in the sheet conveyance direction on the placement surface of the sheet placement portion. Detecting means;
In the sheet placing device comprising a sheet presence / absence detecting means for detecting whether or not a sheet is present in the sheet placing portion,
The sheet length detection means includes: a protrusion that protrudes forward and backward on the placement surface of the sheet placement portion; and a retraction detection portion that detects whether or not the protrusion has retreated below the placement surface. Have
In a state where the sheet mounting portion is closed with respect to the apparatus main body, the protruding portion is configured to take a position retracted below the mounting surface.
When the retraction detection unit detects that the protruding portion has retreated below the placement surface, and the sheet presence / absence detection means detects that there is no sheet, the sheet placement unit is closed with respect to the apparatus main body. A sheet placing apparatus comprising: a determination unit that determines that the sheet is present. In the sheet placing apparatus according to claim 1,
A sheet conveying unit configured to convey the sheet placed on the sheet placing unit to a predetermined conveying destination via a predetermined conveying path;
The sheet placing device, wherein the sheet presence / absence detecting means is provided in the sheet conveying section. In the sheet placing apparatus according to claim 1 or 2,
The projecting portion is provided on a rotating shaft that is rotatably supported with respect to the sheet placing portion, and can move forward and backward with respect to the mounting surface by rotating the rotating shaft,
The retraction detection unit has a transmissive optical sensor,
A sheet placement device, wherein a light shielding part for shielding or transmitting the transmission optical sensor is provided on the rotation shaft. In the sheet mounting apparatus according to claim 1, 2, or 3,
The protrusion is configured with a weight balance that is displaceable between a position that is detected by the retraction detection unit and a position that is not detected when the sheet placement unit is open and closed with respect to the apparatus main body. A sheet placing apparatus characterized by comprising: In the sheet mounting apparatus according to claim 1, 2, or 3,
When the sheet placement portion is closed with respect to the apparatus main body, a pressing portion is provided at a position facing the protrusion portion of the apparatus main body to push the protrusion downward toward the placement surface. Sheet placing device. In the sheet placing apparatus according to claim 1, 2, 3, 4 or 5,
The sheet placement device includes a sheet presence / absence detection filler and a transmission type optical sensor. In the sheet placing apparatus according to claim 1, 2, 3, 4, 5 or 6,
The sheet placement device, wherein the sheet presence / absence detection means is a reflective optical sensor. In an image forming apparatus for forming an image on a sheet by feeding a sheet stacked on a sheet placing apparatus to an image forming unit by a sheet conveying unit,
8. An image forming apparatus using the sheet placing apparatus according to claim 1, 2, 3, 4, 5, 6 or 7 as the sheet placing apparatus. The image forming apparatus according to claim 8.
A display unit for displaying predetermined information;
When the determination unit determines that the sheet placement unit is not closed with respect to the apparatus main body, the operation unit of sheet conveyance by the sheet conveyance unit from the sheet placement unit is displayed on the display unit. An image forming apparatus. The image forming apparatus according to claim 8 or 9,
An image forming apparatus that shifts the image forming unit to an image forming preparation state when the determining unit determines that the sheet placement unit is not closed with respect to the apparatus main body.

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