JP2019026449A - Feeding device and image forming apparatus - Google Patents

Abstract

To provide a feeding device capable of improving productivity without increasing cost and increasing size.SOLUTION: A feeding device 6 comprises: a sheet stacking table 26 on which a sheet bundle is stacked; elevating means 47 for elevating and lowering the sheet stacking table 26; sheet lifting means 48 for supplying air from the leading end side in the sheet conveying direction of the sheet bundle to lift up at least one sheet S out of the sheet bundle; sheet conveying means 25 comprising sheet suction means 45 for sucking the sheet S and sucking and conveying the sheet S lifted from the sheet bundle by the sheet lifting means 48; and judging means for judging whether or not the lift of the sheet S by the sheet lifting means 48 is normally performed. As the judging means, a contact image sensor 41 is used.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a feeding device and an image forming apparatus.

Conventionally, an air pick sheet feeding method has been adopted in which air is blown to a stack of stacked sheets, and the sheets floated by the air are adsorbed by an adsorption belt, and then the sheets are conveyed one by one by running the adsorption belt. A feeding device is known.
In such a feeding apparatus that sucks the uppermost sheet with an adsorption belt and blows air between the sheets in order to separate the first and second sheets, the uppermost sheet is fed from the uppermost position. Since the flying state of the sheets up to the lower level is not monitored for each sheet, there is a problem in that feeding is performed while the floating state is unstable, and non-feeding or double feeding occurs. In particular, when the productivity is increased, the air blowing time is insufficient, so that the sheet is fed without being separated, and non-feeding or double feeding occurs.

  In order to solve the above-mentioned problems, a camera is provided in the vicinity of the stacked sheets in order to reliably separate the sheets, and whether the uppermost sheet and the second sheet are separated by the camera image. There has been proposed a technique for determining whether or not (see, for example, “Patent Document 1”).

The above-described technique has a problem that a small camera that can be mounted inside the feeding device has a limited number of frames, and cannot cope with an increase in productivity. In addition, when a high-speed camera with a large number of frames is introduced, the cost is greatly increased, and the camera itself becomes large and cannot be placed in the apparatus.
SUMMARY An advantage of some aspects of the invention is that it solves the above-described problems and provides a feeding device and an image forming apparatus capable of improving productivity without increasing cost and increasing size.

  The invention according to claim 1 is a sheet stacking table for stacking sheet bundles, elevating means for moving up and down the sheet stacking table, and supplying air from the leading end side in the sheet conveying direction of the sheet bundle to at least remove from the sheet bundle. A sheet floating unit that floats a sheet; a sheet suction unit that sucks the sheet; a sheet conveying unit that sucks and conveys a sheet that has floated from the sheet bundle by the sheet floating unit; and a sheet that is formed by the sheet floating unit. Judgment means for judging whether or not the levitation is normally performed, and a contact image sensor is used as the judgment means.

  According to the present invention, the state of the sheet before feeding is monitored by the contact image sensor, the uppermost sheet is adsorbed by the sheet suction means, and the uppermost sheet and the second sheet are separated. Since the sheet is fed after confirming that the sheet is fed together, a feeding device that can reliably prevent the occurrence of unfeeding and double feeding of sheets while maintaining low cost and high productivity. Can be provided.

1 is a schematic view of an image forming apparatus to which an embodiment of the present invention can be applied. It is a schematic perspective view of the sheet tray used for one embodiment of the present invention. It is the schematic which shows the feeding apparatus used for one Embodiment of this invention. It is a block diagram of the control means used for one Embodiment of this invention. It is the schematic explaining the state of the feeder in the 1st Embodiment of this invention, and the output value of a contact | adherence image sensor. It is the schematic explaining the state of the feeder in the 1st Embodiment of this invention, and the output value of a contact | adherence image sensor. It is the schematic explaining the state of the feeder in the 1st Embodiment of this invention, and the output value of a contact | adherence image sensor. It is a flowchart explaining operation | movement of the feeding apparatus in the 1st Embodiment of this invention. It is a flowchart explaining operation | movement of the feeding apparatus in the 2nd Embodiment of this invention.

FIG. 1 shows a color printer as an image forming apparatus to which an embodiment of the present invention can be applied. In FIG. 1, a color printer 1 is an electrophotographic color image forming apparatus that forms a color image by a plurality of image forming units which are tandem type image forming units. A paper unit 12, a transfer unit 13, a fixing unit 14, and a paper discharge unit 15 are provided.
A feeding device 54 for feeding sheets to the color printer 1 is attached to the right side of the apparatus main body 3.

  The image forming unit 11 forms a toner image of special (S), which is a special color such as colorless and transparent, in addition to four colors of yellow (Y), magenta (M), cyan (C), and black (K). It consists of five image forming units 2S, 2Y, 2M, 2C, and 2K that output. Each image forming unit 2 uses special toners, yellow toners, magenta toners, cyan toners, and black toners of different colors as image forming materials, but the configuration other than these toners is the same and is replaced when the lifetime is reached. . Each image forming unit 2 is detachable from the apparatus main body 3 and constitutes a process cartridge. Hereinafter, each image forming unit 2 will be described using the image forming unit 2K for forming a black toner image as an example.

The image forming unit 2K includes a charging device 4K, a photosensitive drum 5K as an image carrier, a developing device 6K, a charge eliminating device 7K, a photoconductor cleaning device 8K, and the like. These devices are held by a main body which is a common holding member, and each of the above-described devices can be replaced at the same time by detaching the main body integrally with the device main body 3.
An exposure device 9 is disposed above each image forming unit 2. The exposure device 9 exposes and scans the photosensitive drums 5S, 5Y, 5M, 5C, and 5K with laser light emitted from a laser diode, based on image information sent from an external device such as a personal computer.

The photosensitive drum 5K is driven to rotate counterclockwise in FIG. 1 by a motor (not shown). The charging device 4K generates a discharge between the charging wire and the outer peripheral surface of the photosensitive drum 5K by applying a charging bias to the charging wire, thereby uniformly charging the surface of the photosensitive drum 5K ( Charging step).
An electrostatic latent image for black is formed on the surface of the charged photosensitive drum 5K by optical scanning of the laser light emitted from the exposure device 9 (exposure process). The black electrostatic latent image is developed by the developing device 6K using black toner to become a black toner image (development process). The formed black toner image is primarily transferred onto an intermediate transfer belt 10 described later (primary transfer process).

The neutralization device 7K neutralizes the surface of the photosensitive drum 5K after the black toner image is primarily transferred onto the intermediate transfer belt 10 (a neutralization process). The photoconductor cleaning device 8K includes a cleaning blade and a cleaning brush, and removes and collects transfer residual toner remaining on the surface of the photoconductor drum 5K that has been neutralized by the neutralization device 7K (cleaning step).
In FIG. 1, a series of image forming processes similar to those of the image forming unit 2K are performed in the other image forming units 2S, 2Y, 2M, and 2C, and special images are respectively formed on the photosensitive drums 5S, 5Y, 5M, and 5C. A toner image, a yellow toner image, a magenta toner image, and a cyan toner image are formed.

The paper feed unit 12 supplies a sheet S such as transfer paper to the transfer unit 13 through the paper feed path 16, and includes a paper feed tray 17, a paper feed roller 18, and a separation roller pair 19 that are sheet storage units. have.
The sheet feeding roller 18 feeds the uppermost sheet S among the sheets S stacked on the sheet feeding tray 17 to the separation roller pair 19 by its rotation.
The separation roller pair 19 separates the sheets S fed by the paper feed roller 18 one by one and feeds them toward the paper feed path 16. The paper feeding unit 12 employs central reference paper feeding that feeds a sheet based on the center in the sheet width direction Y orthogonal to the sheet conveyance direction X.

  The registration roller pair 20 feeds the sheet S toward the secondary transfer nip portion at the timing when the toner image forming portion on the intermediate transfer belt 10 reaches the secondary transfer nip portion of the secondary transfer portion 21. The registration roller pair 20 is configured to have a skewered dumpling shape that is divided into a plurality of divisions in the sheet width direction Y. Each sheet feeding path including the sheet feeding path 16 that is a sheet conveying path appropriately includes a sheet guide member made of a thin plate member for guiding the sheet to the downstream side in the sheet conveying direction X.

The transfer unit 13 is disposed below each image forming unit 2, and includes a driving roller 22, a driven roller 23, an intermediate transfer belt 10, primary transfer rollers 24 </ b> S, 24 </ b> Y, 24 </ b> M, 24 </ b> C, 24 </ b> K, and a secondary transfer roller 25. A secondary transfer counter roller 28 and a belt cleaning device 29 are provided.
The intermediate transfer belt 10 is stretched by a driving roller 22, a driven roller 23, a secondary transfer counter roller 28, each primary transfer roller 24, and the like disposed inside the loop. The intermediate transfer belt 10 is driven by a driving roller 22 that is driven to rotate clockwise in FIG. 1 by a driving unit (not shown), and moves while being in contact with each photosensitive drum 5.

  Each primary transfer roller 24 is disposed to face each corresponding photosensitive drum 5 via the intermediate transfer belt 10, and rotates following the driving of the intermediate transfer belt 10. Thus, a primary transfer nip portion where the surface of the intermediate transfer belt 10 and the surface of each photosensitive drum 5 abut is formed. A primary transfer bias is applied to each primary transfer roller 24 from a primary transfer bias power source, whereby a primary transfer electric field is generated between each color toner image on each photosensitive drum 5 and each primary transfer roller 24. Is formed. Then, the color toner images are sequentially superimposed and transferred onto the intermediate transfer belt 10.

  The toner image formed on the surface of the photoconductor drum 5S for the special image enters the primary transfer nip portion for the special image as the photoconductor drum 5S rotates. Then, the special toner image is primarily transferred from the photosensitive drum 5S onto the intermediate transfer belt 10 by the action of the transfer electric field and the nip pressure. In this way, the intermediate transfer belt 10 on which the special toner image has been primarily transferred subsequently passes sequentially through the primary transfer nip portion for each color image of yellow, magenta, cyan, and black, and the photosensitive drums 5Y and 5M. , 5C, and 5K, yellow, magenta, cyan, and black toner images are sequentially superimposed and transferred onto the special toner image. By this primary transfer, a superimposed toner image having both a full color toner image and a special color toner image such as colorless and transparent is formed on the intermediate transfer belt 10.

The secondary transfer roller 25 rotates with the intermediate transfer belt 10 and the sheet S sandwiched between the secondary transfer counter roller 28. Thus, a secondary transfer nip portion where the surface of the intermediate transfer belt 10 and the secondary transfer roller 25 abut is formed. While the secondary transfer roller 25 is grounded, a secondary transfer bias is applied to the secondary transfer counter roller 28 by a secondary transfer bias power source.
Residual toner that has not been transferred to the sheet S remains on the intermediate transfer belt 10 after the secondary transfer that has passed through the secondary transfer nip. The transfer residual toner is removed from the surface of the intermediate transfer belt 10 by a belt cleaning device 29 provided with a cleaning blade in contact with the surface of the intermediate transfer belt 10, thereby cleaning the intermediate transfer belt 10.

  The fixing unit 14 includes a heating roller 30 and a pressure roller 31 that presses against the heating roller 30 to form a fixing nip portion. The sheet S sent to the fixing unit 14 is sandwiched between the fixing nips while the unfixed toner image carrying surface is in close contact with the heating roller 30, and the toner in the toner image is melted and softened by heating and pressing. The unfixed toner image is fixed on the sheet S. The sheet S on which the toner image is fixed is conveyed by a pair of conveyance rollers disposed in the sheet discharge path 32 and is moved from the apparatus main body 3 to the outside by the sheet discharge roller pair 33 disposed in the sheet discharge unit 15. The paper is discharged and discharged onto the paper discharge tray 34.

The color printer 1 includes a conveyance switching device 35, a retransmission path 36, a switchback path 37, and a post-switchback path 38, and is configured to be able to execute a duplex mode for forming images on both sides of the sheet S. ing. Specifically, the conveyance switching device 35 includes a first switching claw 52 that switches the subsequent conveyance destination of the sheet S received from the fixing unit 14 to the paper discharge path 32 or the retransmission path 36. When the single-side mode in which image formation is performed on only one side of the sheet S is executed, the conveyance destination is set to the paper discharge path 32.
As a result, the sheet S on which an image is formed only on one surface is sent to the paper discharge roller pair 33 via the paper discharge path 32 and discharged onto the paper discharge tray 34. In addition, when the duplex mode in which images are formed on both sides of the sheet S is executed, the conveyance destination is set to the paper discharge path 32 even when the sheet S having the toner images fixed on both sides is received from the fixing unit 14. . As a result, the sheet S on which images are formed on both sides is discharged onto the paper discharge tray 34.

On the other hand, when the sheet S on which the image is fixed only on one side is received from the fixing unit 14 when the duplex mode is executed, the transport destination is set to the retransmission path 36. A switchback path 37 is connected to the retransmission path 36, and the sheet S sent to the retransmission path 36 is guided by the second switching claw 53 and enters the switchback path 37. When the entire region in the conveyance direction of the sheet S enters the switchback passage 37, the conveyance direction of the sheet S is reversed and the sheet S is switched back.
In addition to the retransmission path 36, a post-switchback path 38 is connected to the switchback path 37, and the switched back sheet S is guided by the second switching claw 53 and enters the post-switchback path 38. At this time, the sheet S is turned upside down, and the sheet S that is turned upside down is retransmitted to the secondary transfer nip portion via the post-switchback path 38 and the sheet feeding path 16. The sheet S on which the toner image is also transferred to the other surface at the secondary transfer nip portion is fixed on the other surface via the fixing portion 14, and then the conveyance switching device 35, the paper discharge path 32, The paper is discharged onto the paper discharge tray 34 via the paper discharge roller pair 33.

Here, the feeding device 54 that is a feature of the present invention will be described.
As shown in FIG. 2, the tray main body 55 constituting the feeding device 54 has a casing shape with an open upper surface, and is stacked on the sheet stacking table 26 on which a large number of sheets S are stacked, and the sheet stacking table 26. A movable end fence 27 for positioning the sheet bundle made of the bundle of sheets S in the conveying direction, a pair of movable side fences 39 and 40 for positioning the sheet bundle in the sheet width direction, and the like. .
The wall surface 26a on the leading end side in the sheet conveying direction of the sheet stacking table 26 functions as a sheet abutting surface with which the end of the stacked sheet bundle comes into contact. The wall surface 26a is formed with a hole 26b that functions as a vent for allowing wind force from each fan, which will be described later, to act on at least the upper portion of the sheet bundle on which it is loaded.

A contact image sensor (CIS) 41 that functions as a determination unit is disposed at the front end of the side fence 39 in the sheet conveyance direction. The contact image sensor 41 has a height from a position lower than the sheet stacking surface of the sheet stacking table 26 to a position exceeding the uppermost sheet of the stacked sheet stack, and is stacked on the sheet stacking table 26. The floating state of each sheet in the sheet bundle can be monitored. The determination result by the contact image sensor 41 is sent to the control means 50 described later.
Since the contact image sensor 41 has a small total data capacity by acquiring an image for each line, it can acquire an image with a period of about 0.5 msec. For this reason, it is possible to detect an image at a pitch of 0.0423 mm at 600 dpi, and a feeding operation can be performed while maintaining high productivity without using a large photographic device such as a high-speed camera.
In the present embodiment, the contact image sensor 41 is disposed such that the sheet contact side surface thereof is flush with the sheet contact side surface of the side fence 39, and together with the side fence 39 in the width direction of the sheet bundle. It is configured to perform alignment.

Above the sheet bundle stacked on the sheet stacking table 26, a suction conveyance unit 56 that constitutes a feeding device 54 and sucks and conveys the uppermost sheet of the sheet bundle one by one is disposed. ing. As shown in FIG. 3, the suction conveyance means 56 includes two rollers 42 and 43 having an axial length slightly shorter than the width of the sheet S, and a plurality of endless rubber belts 44 spanned between the rollers. A suction fan 45 serving as a sheet suction means disposed between the rollers 42 and 43 and a motor 46 that rotationally drives the roller 42 are provided. In the sucking and conveying means 56, the endless rubber belt 44 stretched between the rollers 42 and 43 is driven to run in the direction of the arrow as the roller 42 is rotated in the clockwise direction in FIG. At the same time, the suction fan 45 is operated, and the sheet S is sucked and conveyed from the sheet bundle by the suction force of the suction fan 45. The sheet S sucked and conveyed is conveyed into the apparatus main body 3 via a pair of carry-in rollers 57 arranged on the right side of the apparatus main body 3 in the color printer 1, and the sheet S sent from the paper supply unit 12. Treated similarly.
Further, in the vicinity of the sheet stacking table 26, an elevating unit 47 having a known configuration for moving the sheet stacking table 26 up and down is disposed. The suction fan 45, the motor 46, and the lifting / lowering means 47 described above are controlled by the control means 50 described later.

A first fan 48 that functions as a sheet floating unit and functions as a sheet floating unit and a second fan 49 that functions as a sheet separation unit are disposed downstream of the sheet stacking table 26 in the sheet conveyance direction.
The air blow from the first fan 48 acts on the sheet S positioned above the sheet bundle on the sheet stacking table 26 through the hole 26b. The first fan 48 blows air to float several sheets S positioned above the sheet bundle on the sheet stacking table 26 by its operation.
The air blown from the second fan 49 acts on several sheets S floated from the sheet bundle by the first fan 48 through the hole 26b. The second fan 49 blows air to separate only the uppermost sheet S from the several sheets S that have floated by the operation. Each fan 48 and 49 is controlled by the control means 50 which mentions each operation | movement later.

  FIG. 4 shows a block diagram of the control means 50 used in the feeding device 6. A control means 50 comprising a well-known microcomputer having a CPU, ROM, RAM and the like is disposed in the apparatus main body 1a. Based on the determination result from the contact image sensor 41, the operation, stop and strength of the suction fan 45 are controlled. The operation and stop of the motor 46, the operation and stop of the elevating means 47, the operation, stop and strength of the first fan 48, and the operation, stop and strength of the second fan 49 are controlled. The image read by the contact image sensor 41 is input to the control unit 50 after image processing is performed in the image processing unit 51. The control means 50 is a control means for controlling the operation of the feeding device 54, and a control means (not shown) for controlling the overall operation of the color printer 1 is provided separately.

  As described above, the control unit 50 controls the operation of the motor 46 based on the determination result from the contact image sensor 41. Specifically, the contact image sensor 41 reliably separates one sheet S from the sheet bundle. Control is performed so that the motor 46 is operated only when it is determined that conveyance is possible, and the motor 46 is not operated in other cases. Here, the determination of whether or not one sheet S can be reliably separated and conveyed from the sheet bundle is shown in the state explanatory diagram of the feeding device 6 shown in FIGS. 5, 6, and 7 and FIG. 8. This will be described based on a flowchart.

In FIG. 5 showing the state of the sheet feeding device 54 at the time of sheet feeding, the diagram shown on the right side of the drawing is an output value indicating the state of each sheet S detected by the contact image sensor 41, that is, the contact image sensor. 41 shows the result of determination by 41. When preparations for feeding start in the feeding device 54 are completed (ST01), the sheet floating state is monitored by the contact image sensor 41 (ST02). In this determination by monitoring, it is first determined whether or not the sheet S is adsorbed to the endless rubber belt 44 (ST03). Then, as indicated by the symbol A in FIG. 5, when the sheet S is detected at the position of the endless rubber belt 44, it is determined that the unfeed of the sheet S is prevented and the first condition is achieved. The
On the other hand, as indicated by symbol B in FIG. 6, when the sheet S is not detected at the position of the endless rubber belt 44, it is determined that unfeeding of the sheet S is not prevented, and the first The condition is not met.
Further, in the state indicated by the symbol C shown in FIG. 7, the sheet S is detected at the position of the endless rubber belt 44, and the first condition is achieved.

Further, in FIG. 5, it is determined whether or not the distance X between the position A of the uppermost sheet S and the position D of the second sheet S is greater than or equal to a predetermined distance (ST04). When the position A and the position D are separated from each other by a predetermined distance or more, it is determined that the double feeding of the sheet S is prevented, the second condition is achieved, and the control unit 50 is permitted to feed. Judgment is made (ST05).
The distance Y between the position B of the uppermost sheet S and the position E of the second sheet S shown in FIG. 6 is a predetermined distance or more, and the second condition is achieved.
On the other hand, the distance Z between the position C of the uppermost sheet S and the position F of the second sheet S shown in FIG. 7 is not more than a predetermined distance, and double feeding of the sheets S is not prevented. As a result, the second condition is not satisfied.

Only when both the first condition and the second condition described above are satisfied, that is, in the state shown in FIG. 5, the control unit 50 can reliably separate and convey one sheet S from the sheet bundle. And the motor 46 is operated. As a result, the endless rubber belt 44 that separates and sucks only one sheet S is driven to run, and the sheet S is reliably separated and fed from the sheet bundle (ST06).
With the above-described configuration, the state of the sheet S before feeding is monitored by the contact image sensor 41, and the uppermost sheet S is adsorbed by the endless rubber belt 44, and the uppermost sheet S and the second sheet S. Since the sheet S is fed after confirming that they are separated from each other, it is possible to reliably prevent the sheet S from being unfed and from being double fed while maintaining low cost and high productivity. A possible feeding device can be provided.

Next, a second embodiment of the present invention will be described. In the second embodiment, when the sheet S is not attracted to the endless rubber belt 44 in the monitoring by the contact image sensor 41 in the first embodiment, that is, the sheet S is not attracted to the suction fan 45 as shown in FIG. When the first condition is not satisfied, and when the distance between the uppermost sheet S and the second sheet S is not more than a predetermined distance, that is, when the second condition is not satisfied as shown in FIG. The control unit 50 controls the operations of the suction fan 45, the first fan 48, and the second fan 49 so that the first condition and the second condition are satisfied.
The operation of the feeding device 54 in the second embodiment will be described based on the flowchart shown in FIG.

When preparations to start feeding in the feeding device 54 are completed (ST11), the sheet floating state is monitored by the contact image sensor 41 (ST12). In this determination by monitoring, the control means 50 determines whether or not the sheet S is adsorbed to the endless rubber belt 44 (ST13). As shown in FIG. 5, when the sheet S is detected at the position of the endless rubber belt 44, it is determined that the unfeed of the sheet S is prevented, and the first condition is achieved.
In step ST13, as shown in FIG. 6, when the sheet S is not detected at the position of the endless rubber belt 44, it is determined that the unfeeding of the sheet S is not prevented, and the first condition is not satisfied. At this time, the control means 50 increases the rotation speed of the suction fan 45 or the first fan 48 to enhance the operation, and controls the operation of the fans 45 and 48 so that the sheet S reaches the position of the endless rubber belt 44. . Here, if the first condition is not satisfied even if the fans 45 and 48 are individually controlled to operate, the fans are controlled to operate simultaneously (ST14).

When the first condition is achieved in step ST13, the control means 50 next determines whether or not the distance between the position A of the uppermost sheet S and the second sheet S is a predetermined distance or more. Is determined (ST15). When the uppermost sheet S and the second sheet S are separated from each other by a predetermined distance or more, it is determined that the double feeding of the sheet S is prevented, the second condition is achieved, and the control means 50 Permits the feeding (ST16).
Only when both the first condition and the second condition described above are satisfied, that is, in the state shown in FIG. 5, the control unit 50 can reliably separate and convey one sheet S from the sheet bundle. And the motor 46 is operated. As a result, the endless rubber belt 44 that separates and sucks only one sheet S is driven to run, and the sheet S is reliably separated and fed from the sheet bundle (ST06).

In step ST15, as shown in FIG. 7, when the distance between the uppermost sheet S and the second sheet S is not a predetermined distance or more, it is determined that the double feeding of the sheet S is not prevented. Therefore, the second condition is not satisfied. At this time, the control means 50 increases the rotation speed of the second fan 49 to enhance the operation, and the operation of the second fan 49 so that the distance between the uppermost sheet S and the second sheet S is more than a predetermined distance. Control is performed (ST17).
When both the first condition and the second condition are satisfied, the control unit 50 determines that one sheet S can be reliably separated and conveyed from the sheet bundle and operates the motor 46. As a result, the endless rubber belt 44 that separates and sucks only one sheet S is driven to run, and the sheet S is reliably separated and fed from the sheet bundle (ST18).

  With the configuration described above, the same effects as those of the first embodiment can be obtained, and the control means 50 automatically controls the operations of the fans 45, 48, and 49 based on information from the contact image sensor 41. Since the uppermost sheet S on the sheet bundle is reliably separated and fed, the occurrence of unfeeding and double feeding of the sheet S is surely and automatically prevented, and workability is improved in each stage. It is possible to provide a feeding device capable of performing the above.

  In each of the above-described embodiments, the contact image sensor 41 used as the determination unit is arranged to function as a part of the side fence 39. With this configuration, it is possible to easily focus on the end surface of the sheet S, and it is possible to save space without waste in the layout. In the present embodiment, the contact image sensor 41 and the control means 50 are connected by a flexible flat cable (FFC) (not shown), and the contact image sensor 41 is disposed on the side fence 39 side located on the front side of the apparatus.

  This is a configuration in which the contact image sensor 41 does not interfere with the suction conveyance means 56 when the sheet stacking table 26 is pulled out because the sheet stacking table 26 can be pulled out toward the front side. In the case of a configuration that can be pulled out in the direction, it is desirable that the contact image sensor 41 be disposed on the side fence 40 side located on the back side of the apparatus in order to prevent interference such as FFC when the sheet stacking table 26 is pulled out. .

  In each of the above-described embodiments, the sheet S is shown as a recording medium on which an image is formed. However, the sheet S is not limited to recording paper, and is thick paper, postcard, envelope, plain paper, thin paper, coated paper ( Coated paper, art paper, etc.), tracing paper, OHP sheet, OHP film, resin film, etc., any material can be used as long as it has a sheet shape and can form an image.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to such specific embodiments, and unless specifically limited by the above description, the present invention described in the claims is not limited. Various modifications and changes are possible within the scope of the gist.
For example, in the above-described embodiment, the feeding device 54 has a different configuration that can be connected to the color printer 1. However, the image forming apparatus may have a configuration in which the same configuration as that of the feeding device 54 is incorporated.
The effects described in the embodiments of the present invention are merely examples of the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

1 Image forming device (color printer)
26 Sheet loading table 39 Side fence 41 Judging means (contact image sensor)
45 Sheet suction means (suction fan)
47 Lifting means 48 Sheet floating means (first fan)
49 Sheet separating means (second fan)
50 control means 54 feeding device 56 sheet conveying means (suction conveying means)
S sheet

Japanese Patent No. 5799986

Claims (9)

A sheet stacking table for stacking sheet bundles;
Elevating means for elevating and lowering the sheet stacking table;
Sheet floating means for supplying air from the leading end side in the sheet conveying direction of the sheet bundle to float at least one sheet from the sheet bundle;
A sheet conveying means for sucking a sheet, and a sheet conveying means for sucking and conveying the sheet floated from the sheet bundle by the sheet floating means;
Determination means for determining whether or not the sheet floating by the sheet floating means is normally performed,
A feeding device in which a contact image sensor is used as the determination means. The feeding device according to claim 1,
A feeding device comprising: control means for starting feeding of a sheet when it is confirmed by the judging means that the sheet is normally lifted. The feeding device according to claim 2,
The control means controls the operation of the sheet floating means, and the control means strengthens the operation of the sheet floating means when the uppermost sheet is not sucked by the sheet suction means within a predetermined time. A feeding device. In the feeding device according to any one of claims 1 to 3,
A sheet feeding device comprising sheet separating means for supplying air to a leading edge of a sheet levitated by the sheet levitating means to separate the uppermost sheet from a lower sheet than the sheet. The feeding device according to claim 4, wherein
The control means controls the operation of the sheet separating means, and the control means strengthens the operation of the sheet separating means when the uppermost sheet is not separated from the lower-order sheets within a predetermined time. A feeding device characterized by that. In the feeding device according to any one of claims 1 to 5,
The control means controls the operation of the sheet suction means, and the control means strengthens the operation of the sheet suction means when the uppermost sheet is not sucked by the sheet suction means within a predetermined time. A feeding device. In the feeding device according to any one of claims 1 to 6,
The feeding device according to claim 1, wherein the determination unit is disposed in the vicinity of a front end portion of the sheet bundle in a sheet conveying direction. In the feeding device according to any one of claims 1 to 7,
A feeding device comprising a side fence that contacts an end portion of the sheet bundle to organize the sheet bundle, and the determination unit is provided at a contact portion of the side fence with the sheet bundle. apparatus.   An image forming apparatus comprising the feeding device according to claim 1.

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