JP2012229077A - Sheet feeder and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of being unable to discriminate whether to be a state of lifting a sheet feeding cassette for feeding a sheet or an excessively stacked state, when recording materials are stacked by the specified number or less in the sheet feeding cassette in a state where a sheet surface position detecting means becomes a detecting state when the sheet feeding cassette is already mounted on a sheet feeding device, in transition to a power-on state from a power-off state or return from a sleep state.SOLUTION: In the power-on state or sleep return, for determining whether or not to be excessively stacked, a sheet feeding part a paper feeding part 42 is lowered. Output of a sensor 101 is detected when a sheet surface of the recording material 10 is pressed. It is determined that the sheet feeding cassete is in the excessively stacked state when the sensor 101 is still turned on, and is in a sheet-feedable state when the sensor 101 is turned off.

Description

  The present invention relates to an image forming apparatus such as a printer, a copying machine, and a facsimile machine, which includes a paper feeding device that raises a paper feeding cassette on which recording materials are stacked and feeds paper.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a printer performs image formation by sequentially transporting recording materials stacked in a paper feed cassette to an image forming unit. In such an image forming apparatus, when paper is fed in an overloaded state in which more than a specified number of recording materials are loaded in a paper feeding cassette, the paper is fed in a state where the height of the paper surface is higher than the ideal paper feeding position. It will be. For this reason, there is a concern that the recording material may be wrinkled or torn, or the occurrence rate of jam may be increased. Therefore, in order to eliminate such a state, Patent Document 1 includes a detection unit that detects the presence or absence of a recording material loaded in a paper feed cassette and a detection unit that detects the height of the recording material. Then, before raising the paper cassette for feeding the recording material, if both detection means are in the detection state, it is judged that the recording material is overloaded, and the recording material is prohibited. Disclosed is a method for suppressing the damage.

JP2008-254896

  However, when the image forming apparatus transitions from power OFF to ON or returns from the sleep state, there is a state in which the paper feed cassette is already mounted on the paper feed device and the paper surface position detection unit is in the detection state. In such a state, it is determined whether the recording material is loaded in the paper feed cassette in a predetermined number or less and the paper feed cassette is raised for paper feeding or overloaded. There is a possibility that it is not possible.

  The invention according to the present application has been made in view of the above situation, and an object thereof is to accurately determine whether or not a recording material is in an overloaded state using a paper surface detection unit.

  In order to achieve the above object, a stacking unit for stacking a recording material, a sheet feeding unit for feeding a recording material stacked on the stacking unit, and a detecting unit for detecting the recording material stacked on the stacking unit, And a drive means for moving the paper feed means, and after the detection means detects that there is a recording material, the paper feed means is moved by the drive means and the recording material loaded on the stacking means is loaded. And a control means for discriminating a stacked state of the recording material according to a detection result of pressing and detecting the recording material again by the detection means.

  According to the configuration of the present invention, it is possible to accurately determine whether or not the recording material is overloaded using the paper surface detection means.

Schematic configuration diagram of an image forming apparatus Block diagram illustrating an example of a system configuration of an image forming apparatus Schematic configuration diagram of the paper feed mechanism provided in the paper feeder Flow chart showing overload detection method

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments do not limit the invention according to the claims, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention.

(First embodiment)
FIG. 1 is a schematic configuration diagram of an image forming apparatus including a sheet feeding device. A paper feeding device 2 is connected to the image forming apparatus 1. The sheet feeding device 2 includes a sheet feeding cassette 21 as a stacking unit that can be opened and closed toward the front side, and a plurality of recording materials 10 are stacked. The recording material 10 loaded in the paper feed cassette 21 is disposed on the bottom plate 22. When feeding the stacked recording materials 10, the bottom plate 22 is raised until the paper surface is detected by the sensor 101. When the paper surface is detected by the sensor 101, the recording material 10 is fed one by one by the paper feeding roller 31. The fed recording material 10 is transported by transport rollers 32 and 33. The sensor 102 is a sensor for detecting the conveyance state of the recording material 10.

  The recording material 10 is conveyed to the image forming unit by the conveyance roller. The image forming unit includes a photosensitive drum, a developing roller, a charging roller, a scanner unit, and the like. First, the photosensitive drum is uniformly charged by the charging roller. Subsequently, exposure is performed by the scanner unit to form a latent image. The formed latent image is developed by a developing roller, and a toner image is formed on the photosensitive drum. The formed toner image is transferred onto the recording material 10 by a transfer roller. The recording material 10 to which the toner image has been transferred is conveyed to the fixing unit. The fixing unit fixes the toner image transferred to the recording material 10 by the heating roller and the pressure roller. The recording material 10 on which the toner image is fixed is discharged out of the apparatus.

  FIG. 2 is a block diagram for explaining an example of the system configuration of the image forming apparatus. The CPU 200 is mounted on the image forming apparatus 1 or the paper feeding apparatus 2 and controls the operations of the image forming apparatus 1 and the paper feeding apparatus 2. The CPU 200 includes an overload determination unit 211 as a control function, a paper feed unit lowering amount adjustment unit 212, and a display control unit 213 as a display unit. The CPU 200 is connected to the sensor unit 100, the drive unit 201, and the display unit 202. The sensor unit 100 includes a sensor 101 and a sensor 102 that are arranged in the sheet feeding device 2. The sensor 101 is a sensor that detects the paper surface of the recording material 10 loaded in the paper feed cassette 21 as described above, and transmits the paper surface state to the CPU 200. The sensor 101 is ON when a paper surface is detected, and is OFF when a paper surface is not detected. The sensor 102 detects the presence / absence of the recording material after the recording material is conveyed by the conveyance roller 33 and transmits it to the CPU 200. It is ON when a recording material is detected, and OFF when no recording material is detected.

  The drive unit 201 includes a paper feed roller 31, a conveyance roller 32, a conveyance roller 33, and a gear 30 shown in FIG. 3 to be described later, and controls each drive portion by a plurality of drive sources based on drive data input from the CPU 200. To do. The overload determination unit 211 lowers the paper feeding unit 42 by a predetermined amount more than that during normal paper feeding when the power is turned on or returns from sleep, and then checks the state of the sensor 101 to determine whether it is overloaded. . The sheet feeding unit lowering amount adjusting unit 212 adjusts the amount of lowering when the sheet feeding unit 42 is lowered. Based on the determination result of the overload determination unit 211, the display control unit 213 causes the display unit 202 to display that the paper feed cassette 21 is in an overload state when it is overloaded.

  FIG. 3 is a schematic configuration diagram of a paper feeding mechanism provided in the paper feeding device. The recording material 10, the paper feed roller 31, the bottom plate 22, and the sensor 101 are the same as those in FIG. The gear 30 is for driving the rack and pinion 41 up and down, and rotates by driving a stepping motor (not shown). By switching the rotation direction of the stepping motor between normal rotation and reverse rotation, the upward driving and the downward driving of the rack and pinion 41 are switched. The paper feed unit 42 and the paper feed roller 31 connected to the paper feed unit 42 move up and down according to the up and down drive of the rack and pinion 41.

  FIG. 3A shows a state before feeding. Before feeding paper, the paper feed roller 31 is at a position H 1 higher than the paper surface position of the recording material 10. FIG. 3B shows a state where paper feeding is performed. When feeding paper, the gear 30 is rotated, and the rack and pinion 41 and the paper feed unit 42 are lowered until the paper feed roller 31 contacts the paper surface of the recording material 10. Thereafter, the sheet feeding roller 31 is rotated by a motor of a driving source different from the stepping motor of the gear 30 (not shown) to feed the recording materials 10 one by one. After the end of paper feeding, the rotation direction of the stepping motor is switched to the reverse direction, the gear 30 is rotated in the reverse direction, the rack pinion 41 and the paper feed unit 42 are raised, and the paper feed roller 31 is returned to the position H1.

  FIG. 3C shows a state in which overload detection is performed. When overload detection described later is performed, the rack and pinion 41 and the paper feed unit 42 are further lowered by a predetermined amount from the state where the paper feed roller 31 is in contact with the paper surface of the recording material 10 as shown in FIG. After being lowered, the state of the sensor 101 is checked to determine whether it is overloaded. That is, it is determined whether or not it is overloaded based on the detection result of the sensor 101 when the recording material 10 is pressed by the paper supply unit 42. Specifically, if the sensor 101 remains ON, it is determined that the vehicle is overloaded. At this time, the lowering amount is limited by the torque limiter 40 so as not to be lowered more than a predetermined amount. The overload detection will be described in detail with reference to FIG.

  FIG. 4 is a flowchart showing a method of overload detection. Here, as an example, after detecting that the paper feed cassette 21 is closed, overload detection is performed before the paper feed operation is performed. In S101, the CPU 200 confirms whether the sensor 101 is ON. When the sensor 101 is turned off and the paper surface of the recording material 10 is not detected, in S110, the CPU 200 starts to lift up the bottom plate 22, and sets the paper surface position of the recording material 10 to a position H3 where the paper can be fed. In S107, the CPU 200 informs that the paper feed cassette 21 can be fed.

  When the sensor 101 is turned on and the paper surface of the recording material 10 is detected, in step S102, the CPU 200 determines whether the image forming apparatus 1 is in a power-on state or a sleep return time. If the image forming apparatus 1 is not at the time of turning on the power or returning from the sleep mode, the sensor 101 is on even though the lift-up is not performed. Therefore, in S108, the CPU 200 determines that it is in an overloaded state. In step S <b> 106, the CPU 200 raises the paper feed unit 42. After that, in S109, the CPU 200 notifies that the paper feed cassette 21 is prohibited from being fed.

  When the image forming apparatus 1 is turned on or is in the sleep mode, the CPU 200 lowers the paper feed unit 42 in S103 to determine whether the image forming apparatus 1 is overloaded. As shown in FIG. 3B, during normal paper feeding, the paper feeding unit 42 is lowered to a position where the paper feeding roller 31 contacts the paper surface of the recording material 10. On the other hand, when detecting overloading, as shown in FIG. 3C, the rack and pinion 41 is further lowered and the sheet feeding unit 42 is lowered as compared with the normal sheet feeding. At this time, H2 in FIG. 3B is the upper limit position of the sheet surface where the recording material 10 can be fed, and H3 is the position where the sensor 101 detects the sheet surface of the recording material 10 when the bottom plate 22 is raised. The amount to be lowered when overloading is detected is greater by the difference between H2 and H3 than during normal paper feeding, and the paper surface position of the recording material 10 is pushed down. FIG. 3C illustrates a case where the paper surface position H3 of the recording material 10 is pushed down to a position H4 as a difference between the position H2 and the position H3. The limit of the force that pushes down the paper surface position of the recording material 10 is limited by the torque limiter 40 so as not to push down from the position H3 to the position H4.

  After lowering the paper feed unit 42, in S104, the CPU 200 confirms whether the sensor 101 is turned off. When the sensor 101 is turned on and the paper surface of the recording material 10 is detected, the sensor 101 is not turned off even if the paper surface position is pushed down. In S108, the CPU 200 determines that it is in an overloaded state. In step S <b> 106, the CPU 200 raises the paper feed unit 42. After that, in S109, the CPU 200 notifies that the paper feed cassette 21 is prohibited from being fed.

  When the sensor 101 is turned off and the paper surface of the recording material 10 is not detected, the CPU 200 determines in S105 that the paper surface position can be fed. In step S <b> 106, the CPU 200 raises the paper feed unit 42. Thereafter, in S107, the CPU 200 notifies that the paper feed cassette 21 can be fed. Note that when the paper feeding unit 42 is lowered when overloading is detected in S103, control may be performed so that the descent of the paper feeding unit 42 is immediately stopped when the sensor 101 is turned off and the paper surface is no longer detected.

  As described above, when the image forming apparatus 1 is turned on or when the sensor 101 is turned on when the image forming apparatus 1 returns from sleep, the paper surface of the recording material 10 may be detected. At that time, before starting the paper feeding operation, the paper feeding unit 42 is lowered by a predetermined amount to check the state of the sensor 101. When the sensor 101 remains ON, it is overloaded. When the sensor 101 is turned off, it is determined that the paper can be fed. Can be prevented from starting. Therefore, even in a paper feeding device that has a single paper surface detecting means for detecting the paper surface position, it is possible to accurately determine whether or not the recording material is overloaded using the paper surface detecting means.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Paper feed apparatus 10 Recording material 21 Paper feed cassette 22 Bottom plate 41 Rack and pinion 42 Paper feed part 101 Sensor 200 CPU

Claims (7)

Loading means for loading recording materials;
Paper feeding means for feeding the recording material loaded on the loading means;
Detecting means for detecting the recording material loaded on the loading means;
Driving means for moving the paper feeding means;
After the detection means detects that there is a recording material, the drive means moves the paper feeding means, presses the recording material loaded on the stacking means, and the detection means detects the recording material again. And a control unit that determines a stacked state of the recording material according to the detected result.   As a result of detecting the recording material again by the detection means, the control means determines that the recording material is overloaded when it is detected that there is a recording material, and is not overloaded when it is detected that there is no recording material. The paper feeding device according to claim 1, wherein the paper feeding device is determined.   3. The paper feeding device according to claim 2, wherein when the control unit determines that the recording material is not overloaded, the recording unit feeds the recording material by the paper feeding unit.   3. The paper feeding device according to claim 2, wherein when the recording unit determines that the recording material is overloaded, the control unit prohibits feeding of the recording material by the paper feeding unit. Display means for displaying the status of the recording material loaded on the paper feeding means;
5. The sheet feeding device according to claim 1, wherein the control unit displays a result of determining a stacking state of the recording materials stacked on the sheet feeding unit on the display unit. 6. .   The sheet feeding device according to claim 1, wherein the control unit performs detection by the detection unit when the power is turned on or when returning from sleep. An image forming means for forming an image;
Loading means for loading recording materials;
Paper feeding means for feeding the recording material loaded on the loading means;
Detecting means for detecting the recording material loaded on the loading means;
Driving means for moving the paper feeding means;
After the detection means detects that there is a recording material, the drive means moves the paper feeding means, presses the recording material loaded on the stacking means, and the detection means detects the recording material again. An image forming apparatus comprising: a control unit that determines a stacking state of the recording materials according to the detected result and feeds the recording material to the image forming unit if paper feeding is possible.

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