Paper feeder

Abstract

To provide a paper feed device that can raise the pickup roller without requiring a sensor to detect the opening and closing of the bar, thereby reducing cumbersome operations. [Solution] To achieve the above objective, a paper feeding device according to one embodiment of the present invention comprises a pickup roller, a sensor, and a paper feeding control unit. The pickup roller pulls out sheets of paper one by one from a paper tray on which multiple sheets of paper are stacked. The sensor detects the presence or absence of paper. The paper feeding control unit controls the upward drive of the pickup roller based on the detection result of the sensor.

Description

Technical Field

[0001] The present invention relates to a paper feeding device applicable to the lifting process of a pickup roller.

Background Art

[0002] Conventionally, sensors are provided to identify the state (e.g., open / closed state) of the DP unit of an image forming apparatus.

[0003] For example, in Patent Document 1, the state of the DP unit is identified using two sensors, and the state of the DP is identified according to four states by the two sensors. An image reading apparatus that executes an algorithm for lifting the pickup roller according to the state is disclosed. Also, in Patent Document 2, a document conveying apparatus that controls the pickup roller by arranging a sensor indicating whether document conveyance is possible or not depending on the opening and closing of a cover at the first position or the second position is disclosed. Further, in Patent Document 3, a document reading apparatus having a sensor for discriminating the opening and closing of a cover, a sensor for detecting a document, and a sensor for detecting whether a pickup unit member is in the raised position is disclosed.

[0004] Also, there is a device that aims to reduce costs by not attaching an open / close sensor for the DP cover. In the case of such a device, since there is no sensor when the DP cover is opened / closed or when the DP main body is opened / closed, it is necessary to raise the DP paper feeding pickup roller by panel operation.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

[0006] However, operating the control panel to raise the pickup roller is cumbersome. Also, if a document is inserted without performing this operation, the document will hit the DP paper feed pickup roller, damaging the leading edge of the document.

[0007] In view of the above circumstances, the object of the present invention is to provide a paper feeding device that can raise the pickup roller without requiring a sensor to detect the opening and closing of the cover, thereby reducing complicated operations. [Means for solving the problem]

[0008] To achieve the above objective, a paper feeding device according to one embodiment of the present invention comprises a pickup roller, a sensor, and a paper feeding control unit. The pickup roller pulls out the paper one sheet at a time from the paper tray on which multiple sheets of paper are stacked. The sensor detects the presence or absence of the paper. The paper feed control unit controls the upward drive of the pickup roller based on the detection result of the sensor. [Effects of the Invention]

[0009] According to the present invention, complicated operations can be reduced and the pickup roller can be raised.

[0010] Furthermore, the effects described herein are not necessarily limited to those described herein, and may include any of the effects described herein. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows the external appearance of an image forming apparatus. [Figure 2] This is a cross-sectional view showing the configuration of the document reading unit. [Figure 3] This is a block diagram showing the configuration of an image forming apparatus. [Figure 4] This is a diagram illustrating the state transitions of the paper feed roller (pickup roller). [Figure 5] This diagram shows the control of the rotation direction of the DP motor. [Modes for carrying out the invention]

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0013] Figure 1 shows the external appearance of the image forming apparatus 100.

[0014] The image forming apparatus 100 can selectively perform various modes such as copying, facsimile, scanning, and printing. For example, copying includes printing an image read from a document onto recording paper. For example, facsimile includes transmitting an image read from a document via a public telephone line and printing the received image onto recording paper. For example, scanning includes outputting an image read from a document to an external information terminal. For example, printing includes printing an image input from an external source via a network or the like onto recording paper.

[0015] In Figure 1, the image forming apparatus 100 includes a scanner unit 110, an image forming unit 113, and a paper feeding unit 114.

[0016] The scanner unit 110 can read an image of a document. The scanner unit 110 has a document reading unit 10 and an image reading unit 60. For example, the scanner unit 110 may be configured to read an image of a document using both a sheet-through method, in which the document is moved while the document reading element (scanner head) is stationary, and a scanner head method, in which the document reading element is moved from below the document placed on the platen glass to read the image of the document.

[0017] The original document reading unit (DP) 10 is an ADF (Auto Document Feeder) and has an original document placement table 11 and an original document discharge table 12. The original document reading unit 10 reads the original document placed on the original document placement table 11 and discharges it to the original document discharge table 12. The specific structure of the original document reading unit 10 will be described using FIG. 2.

[0018] The image reading unit 60 is provided with the original document reading unit 10 above it, and acquires image data by reading the image of the original document placed on the platen glass 61 (see FIG. 2).

[0019] For example, the image reading unit 60 is provided with a first original document reading element 62 (see FIG. 2) for reading the front surface of the original document, and the original document reading unit 10 is provided with a second original document reading element 19 (see FIG. 2) for reading the back surface of the original document, so that both sides of the original document may be read in one pass. Note that a contact image sensor (CIS) or the like may be used for the first original document reading element 62 and the second original document reading element 19.

[0020] The image forming unit 113 has an image forming section 113A, a paper feed cassette 113B, a manual feed tray 113C, a paper discharge tray 113D, and a sorter 113E. The paper feed unit 114 has a paper feed cassette 114A. The image forming unit 113 forms an image on the recording paper fed from the paper feed cassette 113B, the manual feed tray 113C, or the paper feed cassette 114A with the image forming section 113A and discharges it to the paper discharge tray 113D or the sorter 113E.

[0021] FIG. 2 is a cross-sectional view showing the configuration of the original document reading unit 10.

[0022] The original document reading unit 10 also has a DP cover 14, a paper feed section 30, a first conveyance roller 16, a second conveyance roller 17, an actuator 18, a second original document reading element 19, and a paper discharge roller 20. The paper feed section 30, the first conveyance roller 16, the second conveyance roller 17, the second original document reading element 17, the actuator 18, the second original document reading element 19, and the paper discharge roller 20 are provided in order from the upstream side in the conveyance direction.

[0023] The DP cover 14 is positioned on the upper surface of the transport path 15 that transports documents, including the paper feed section 30, and covers the document in a way that allows it to be opened and closed. For example, the DP cover 14 can be opened and closed by the user to resolve paper jams or other issues. In this embodiment, no sensor is provided to detect the open or closed state of the DP cover 14.

[0024] The paper feeding unit 30 includes a pickup roller 31, a document presence sensor 32, a stopper 33, and a paper feeding roller 34. Note that the paper feeding unit 30 is shown with some idler gears and other components omitted. The configuration of the paper feeding unit 30 is not limited, and a mechanism for transmitting driving force, such as a rotating shaft or gears, may be configured as desired.

[0025] The pickup roller 31 is configured to move vertically by an actuator (not shown), a rod, or a coil spring, and rotates to feed the document placed on the document tray 11 to the transport path 15. For example, the pickup roller 31 moves up and down between a lower limit position that contacts the upper surface of the document tray 11 and an upper limit position that is a predetermined distance from the document tray 11 (for example, the position where the paper feed unit 30 contacts the DP cover 14).

[0026] The document presence sensor 32 detects the presence or absence of a document. In this embodiment, the detection signal detected by the document presence sensor 32 is output to the paper feed control unit 130, which will be described later. For example, the document presence sensor 32 is a PI sensor, and the presence or absence of a document is detected by the actuator 18 when a document passes through the transport path 15. In this embodiment, the document presence sensor 32 and the actuator 18 function as sensors that detect the presence or absence of paper.

[0027] The stopper 33 allows or restricts the feeding of documents. For example, the stopper 33 allows the document to be fed by rotating when the pickup roller 31 rotates to the feeding position, and restricts the feeding by becoming immobile and contacting the leading edge of the document stack when the pickup roller 31 rotates to the non-feeding position.

[0028] The stack of documents placed on the document tray 11 is transported by the pickup roller 31 and the paper feed roller 34, with the top document in the stack being sent from the paper feed opening to the transport path 15. The documents that are sent out are then transported by the first transport roller 16 and the second transport roller 17. Both sides of the sent-out documents are detected by the actuator 18, and at a predetermined timing, the images of the documents are read by the first document reading element 62 and the second document reading element 19. After that, the documents are discharged from the output opening by the paper output roller 20 and loaded onto the document output tray 12.

[0029] When setting the document in the DP, it is necessary to raise the pickup roller 31. Therefore, when the power of the image forming apparatus 100 is turned on, the operation to raise the pickup roller 31 must be performed after the DP has been read, or after the DP cover 14 (DP body) has been opened or closed.

[0030] However, in order to reduce costs, this image forming apparatus does not have a sensor to detect the opening and closing of the DP cover 14. Therefore, in this embodiment, the image forming apparatus 100 has a paper feed control unit 130 that raises the pickup roller 31 when it detects that the time the document presence sensor 32 has been ON for a certain period of time or longer.

[0031] Figure 3 is a block diagram showing the configuration of the image forming apparatus 100. In Figure 3, the block including the image forming unit 113 and the paper feeding unit 114 is referred to as the printer 120.

[0032] As shown in Figure 3, the image forming apparatus 100 includes a printer 120 and a document reading unit 10. The printer 120 includes an image forming unit 113, a paper feeding unit 114, an operation panel 115, and a control unit 121. The operation panel 115 includes an operation unit 116 that can receive user input and a display unit 117 that displays various settings and statuses of the image forming apparatus 100. For example, the operation unit 116 includes a numeric keypad for inputting the number of prints and an OK button to indicate user approval. Alternatively, for example, an LE display may be used for the display unit 117. In addition, the operation panel may also have a speaker to inform the user of abnormal conditions of the image forming apparatus 100, such as a paper jam.

[0033] The control unit 121 communicates with the document reading unit 10 and controls the image reading operation of the image reading unit 60 according to the timing of document transport. Based on the image data acquired by the reading operation, it controls the image forming unit 113 and the paper feeding unit 114 to perform image forming processing.

[0034] The document reading unit 10 includes a paper feed control unit 130, a pickup roller drive unit 140, a transport roller drive unit 141, a paper discharge roller drive unit 142, and a document presence / absence sensor 32.

[0035] The paper feed control unit 130 includes a CPU (Central Processing Unit) 131, a ROM (Read-only Memory) 132, a RAM (Random Access Memory) 133, and a non-volatile memory 134. In this embodiment, the paper feed control unit 130 performs processing to control the vertical movement (lifting and lowering) of the pickup roller 31.

[0036] The CPU 131 executes a control program stored in the ROM 132, and in response to detection signals from the document presence sensor 32 and various job execution instructions from the user via the control unit 121 of the printer 120 to the operation panel 115, it controls the pickup roller drive unit 140, the transport roller drive unit 141, and the paper output roller drive unit 142.

[0037] ROM 132 stores control programs and other data necessary for transporting documents. RAM 133 is volatile memory and serves as the work area for program execution in CPU 131. Non-volatile memory 134, such as EEPROM (Electrically Erasable Programmable Read-Only Memory), serves as the data storage area for CPU 131.

[0038] Figure 4 is a diagram showing the state transitions of the paper feed roller (pickup roller 31).

[0039] As shown in Figure 4, the state of the paper feed roller is classified into five states: initial state, in operation, operation complete, waiting for JAM (jam) processing, and operation prohibited. The initial state indicates the state when the power to the image forming apparatus is turned on or when it has woken up from sleep mode. In operation indicates the state when the upward drive of the paper feed roller has started. Operation complete indicates the state when the upward drive of the paper feed roller has been completed. Waiting for JAM processing indicates the state when the apparatus is waiting for a paper jam to be resolved. Operation prohibited indicates the state in which the upward control of the pickup roller 31 is prohibited during scanning and transport.

[0040] In this embodiment, we classify the cases into three categories and explain the control methods for each case using Figure 4.

[0041] <Case 1> Case 1 is the operation process when the paper feed roller is raised when the power of the image forming apparatus 100 is turned on.

[0042] As shown in Figure 4, in Case 1, when the power is turned on or the device wakes from sleep mode, the paper feed roller returns to its initial state (ST101). In this state, permission to drive the paper feed roller upward is given by the paper feed control unit 130 (Event: Operation Permission), and the paper feed roller transitions to the operating state (ST102). In ST102, the upward drive of the paper feed roller begins. Once the upward drive of the paper feed roller is complete, the state transitions to operation complete (ST103). This makes it possible to place the document on the document tray 11.

[0043] The black circle 200 outside the frame indicates that the power supply of the image forming apparatus 100 has been turned on and the state transition to the paper feed roller has begun. The black circles 201, 202, and 203 inside the frame indicate that the respective state information has been notified.

[0044] <Case 2> Case 2 describes the operation process when the paper feed roller is raised after the DP reading is complete.

[0045] Figure 5 shows the control of the rotation direction of the DP motor. Depending on the rotation direction, the DP motor can select either raising the pickup roller 31 or transporting the document when scanning. In this embodiment, the CW (Clockwise) of the DP motor raises the pickup roller 31, and the CCW (Counter Clockwise) of the DP motor feeds the document onto the transport path for scanning.

[0046] As shown in Figure 5, the direction of the DP motor when transporting the document is CCW, and since the same motor is used for scanner transport and pickup roller 31 control, the pickup roller 31 goes down. In other words, when DP scanning is complete, the pickup roller 31 needs to be raised.

[0047] Returning to Figure 4, let's explain the upward control of the pickup roller 31 in Case 2. First, in Case 2, the state of the pickup roller 31 is "operation complete" (ST103). The "operation complete" state is reached when an event notification indicating that the upward drive of the pickup roller 31 has been completed is supplied to the paper feed control unit 130.

[0048] Furthermore, upon receiving a scan request, the state of the pickup roller 31 changes to "operation prohibited" (ST104). For example, when a user initiates a scan operation via the control panel 115, a scan request is supplied to the paper feed control unit 130, causing the state of the pickup roller 31 to change to "operation prohibited." In Figure 4, "RUN entry" indicates that the state of the pickup roller 31 transitions from "operating" to "operation prohibited." Similarly, "RUN exit" indicates that the state of the pickup roller 31 transitions from "operation prohibited" to "operating."

[0049] Furthermore, when scanning is complete, the following cases 2-1 and 2-2 occur. Case 2-1 is when there is no jam, or when the first page is not fed (no original document). In this case, the state of the pickup roller 31 transitions from operation prohibited (ST104) to operation in progress (ST102). When the upward drive of the pickup roller 31 is complete, it transitions to operation complete (ST103). This makes it possible to set the original document on the original document tray 11.

[0050] In this context, "no paper feed on the first page" refers to a situation where the first page of the document failed to feed.

[0051] In case 2-2, there is a jam, or the first sheet is not fed (original document present). In this case, in order to raise the pickup roller 31, it is necessary to transition from operation prohibited (ST104) to waiting for jam processing (ST105).

[0052] In ST105, two cases are considered. First, if there is a jam, after the jam is processed, a jam release request command (FD55) is supplied to the paper feed control unit 130, and if there is no document in the paper feed tray, the state of the pickup roller 31 transitions to operating (ST102). Furthermore, when the state of the pickup roller 31 transitions from ST102 to ST103, the upward drive of the pickup roller 31 is completed. This makes it possible to set the document on the document tray 11.

[0053] The transition between the jam-free state (ST106) and the jammed state (ST107) occurs when a notification indicating that a jam has occurred is sent to the paper feed control unit 130, causing the state to transition from ST106 to ST107.

[0054] Furthermore, if the first page of the document is not fed, or if there is no document (ST108), the state of the pickup roller 31 transitions to "operating" (ST102). When the state of the pickup roller 31 transitions from ST102 to ST103, the upward drive of the pickup roller 31 is completed. This makes it possible to set the document on the document tray 11.

[0055] The transition between having a document (ST108) and not having a document (ST109) occurs when the document is removed from ST108, and when a document is placed in ST109, it returns to ST108.

[0056] <Case 3> Case 3 is the operation process of the paper feed roller when the pickup roller 31 is raised by the control panel when the DP cover 14 is opened or closed, or when the DP main unit is opened or closed.

[0057] One cause of paper failure is setting a nearly full stack of documents after opening and closing the DP, or after arranging the document stack on the top surface of the DP. This occurs when the impact applied to the DP exceeds the torque limiter setting value that holds the pickup roller 31, causing the roller to drop and releasing the stopper 33 that holds the documents in place. If a nearly full stack of documents is inserted all the way in with the stopper 33 released, the documents will pass through the stopper 33 and jam between the front handling pad and the upper cover rib (see dashed rectangle 50 in Figure 2), resulting in paper failure.

[0058] For example, in models like the image forming apparatus 100, which are not equipped with sensors to detect the opening and closing of the DP cover 14 or the DP body, the user controls the raising of the pickup roller 31 via the control panel 115. Operating such a control panel 115 is cumbersome. Furthermore, if a document is inserted without operating the control panel 115, the leading edge of the document may be damaged by contact with the pickup roller 31.

[0059] Therefore, in this embodiment, the fact that the document presence sensor 32 is switched on and off for a short time due to the impact applied to the DP is used for impact detection. The control is changed to shorten the time it takes for the document presence sensor 32 to detect the presence or absence of a document, and then raise the pickup roller 31 when a document is detected, thereby returning the stopper 33 to its original position.

[0060] Here, the document presence sensor 32 bounces due to vibrations when the DP cover 14 is opened or closed, or when the DP body is opened or closed. For example, when the DP cover 14 (or DP body) is closed, it takes about 20 ms for the document presence sensor 32 to fall down due to gravity. Therefore, in this embodiment, considering the likelihood, if the document presence sensor 32 outputs a detection time of 6 ms or more, it is determined that the DP cover 14 (or DP body) has been closed. That is, the paper feed control unit 130 drives the pickup roller 31 upward when the detection time from the document presence sensor 32 is output as 6 ms or more, which is shorter than the time it takes for the document presence sensor 32 to determine that a document is present.

[0061] In Case 3, after the operation is completed (ST103), after the DP is opened or closed, or after the stack of documents is arranged on the top surface of the DP, the presence or absence sensor 32 turns ON, and a detection signal (event: document (document present)) is supplied to the paper feed control unit 130, causing the state of the pickup roller 31 to transition to operating (ST102).

[0062] Here, two cases (Case 3-1 and Case 3-2) occur when the upward drive of the pickup roller 31 is initiated. In Case 3-1, the pickup roller 31 has already finished rising because a document has been detected. In other words, paper feeding is possible without any problems. In Case 3-2, the presence or absence of a document has been detected in a short amount of time.

[0063] In Case 3-1, if there is no effect that affects the signal output from the document presence sensor 32 while the pickup roller 31 is operating (while it is being driven upward), the upward movement of the pickup roller 31 is completed, and the state of the pickup roller 31 transitions to operation completed (ST103). In this case, no operation of the control panel 115 is required, and the document can be set by raising the pickup roller 31.

[0064] In Case 3-2, if there is an effect that affects the signal output from the document presence sensor 32 while the pickup roller 31 is operating, the state of the pickup roller 31 is in operation (ST102), and even if the state of the document presence sensor 32 changes (on or off), processing must continue only after the upward drive of the pickup roller 31 is complete. For example, an effect that affects the signal output from the document presence sensor 32 includes cases where the sensor signal (document detection) is quickly turned on or off due to vibrations caused by aligning the document on the DP while the pickup roller 31 is operating. In such cases, the state transition decision is made after waiting until the operation of the pickup roller 31 is complete (after waiting until the operation of the pickup roller 31 is complete, taking into account any fluctuations in document detection).

[0065] In this way, by using the signal from the document presence / absence sensor 32, the state of the pickup roller 31 can be changed and the pickup roller 31 can be raised without any panel operation.

[0066] As described above, the document reading unit 10 according to this embodiment includes a pickup roller 31 that pulls out documents one by one from a document tray 11 on which multiple documents are stacked, a document presence sensor 32 that detects the presence or absence of documents, and a paper feed control unit 130 that controls the upward drive of the pickup roller 31 based on the detection result of the document presence sensor 32. This makes it possible to raise the pickup roller without adding a sensor to detect the opening and closing of the cover, and reduces the complicated operation of the control panel, etc.

[0067] Conventionally, in paper feeders that did not have sensors to detect the opening and closing of the paper dispenser (DP) in order to reduce costs, the pickup roller had to be raised by using the control panel, which was a cumbersome operation.

[0068] This technology determines whether the DP (Disposable Panel) is open or closed based on the on / off behavior of the document presence sensor during opening and closing. In particular, when the DP is closed, the likelihood of the document presence sensor falling due to gravity is considered to shorten the time it takes to detect the presence of a document. If the document presence sensor detects the presence of a document for a predetermined time or longer, the DP is determined to be closed, and the pickup roller is raised. This makes it possible to raise the pickup roller without requiring complicated operations on the control panel, etc. [Explanation of Symbols]

[0069] 10…Manuscript reading section 30…Paper feed section 31... Pickup Roller 32...Manuscript presence / absence sensor 33... Stopper 60...Image reading unit 100…Image forming apparatus 130...Paper feed control unit

Claims

1. A pickup roller pulls out one sheet of paper at a time from a paper tray on which multiple sheets of paper are stacked, A sensor that detects the presence or absence of the aforementioned paper, Based on the detection results of the sensor, a paper feed control unit controls the upward drive of the pickup roller. A paper feeder equipped with the following:

2. A paper feeder according to claim 1, The aforementioned detection result includes detection due to impact applied to the paper feed device. The paper feed control unit controls the upward drive of the pickup roller when the detection result is detected for a predetermined period of time or longer. Paper feed device.

3. A paper feeder according to claim 2, The predetermined time is shorter than the time it takes for the sensor to determine that the paper is present. Paper feed device.

4. A paper feeder according to claim 1 or 2, The paper feed control unit controls the upward drive of the pickup roller when the power to the paper feed device is turned on. Paper feed device.

5. A paper feeder according to claim 1 or 2, further, The paper feeding device has an image reading unit that reads the image on the paper, The paper feed control unit controls the upward drive of the pickup roller after the image reading unit has read the image. Paper feed device.

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