JP2005263375A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus, surely preventing further breakage of jammed sheet and inducing a user to perform suitable jam clearing. <P>SOLUTION: A jam occurrence determination part determines whether or not a jam occurs in a paper transport path from a paper feed cassette to a paper delivery part according to an output signal of a jammed paper detecting sensor (#1). When the occurrence of a jam is decided (YES in #1), it is determined whether or not a paper sheet is delivered from the paper feed cassette according to an output signal from the jammed paper detecting sensor disposed in the vicinity of the paper feed cassette (#2). As a result, when the paper sheet is in the process of being delivered from the paper feed cassette (YES in #2), a lock control part causes a locking mechanism to perform locking operation (#3). Thus, the movement of the paper feed cassette is regulated. As a result, the user finds that the paper feed cassette cannot be drawn out and is induced to perform jam clearing by opening an opening and closing cover. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a printer or a copier that feeds sheets one by one from a sheet storage body that stores sheets in a stacked state and conveys the sheets one by one to a predetermined image forming position.

  An image forming apparatus that forms an image on a sheet includes, for example, an image reading unit 101, a sheet discharge unit 102, an image forming unit 103, and a sheet feeding unit 104 in order from the top in the apparatus main body, as shown in FIG. The image reading unit 101 reads an image of a document and feeds paper one by one from the paper feeding unit 104 to the image forming unit 103, where the image forming unit 103 charges, exposes, develops, and transfers images. After the forming operation is performed, the paper after the image formation is discharged to the paper discharge unit 102.

  The paper feed unit 104 is provided with a paper feed cassette (paper tray) that stores paper in a stacked state so that it can be pulled out from the apparatus main body toward the front side of FIG. In the direction (left side in FIG. 7), and conveyed to the upper image forming unit 103 while being held between the conveying rollers. In Patent Document 1 below, a proposal regarding the structure of the paper feeding unit is made.

  In this way, the image forming apparatus 100 that feeds the stacked sheets inside the apparatus and conveys them upward is arranged in the vicinity of the sheet feed cassette with the sheet fed in the horizontal direction from the sheet feed cassette toward the side wall of the apparatus main body. In general, the conveying roller 105 is configured to change its conveying direction upward and then convey it to the image forming unit 103 along the side wall of the apparatus.

In the image forming apparatus 100 of this type, for example, assuming that a paper jam occurs (jamming occurs) when nipping by the conveyance roller 105, a part of the side wall is usually open / close door 106. By opening the door 106, a predetermined area including the transport roller 105 is exposed, and a paper (jam paper) that is jammed by the transport roller 105 or the like can be easily shortened. It is configured to be removed in time.
JP-A-6-183579

  However, among users who use the image forming apparatus, those who do not know that jammed paper can be easily removed by opening the door 106 when a jam occurs, do not open the door 106. There is a case where the paper cassette is pulled out to remove the jammed paper. In this case, when the paper is being fed out from the paper feed cassette, the other end side of the paper is pulled along with the withdrawal of the paper feed cassette while the one end side is sandwiched between the transport rollers 105. Therefore, the paper on the paper cassette may be further damaged. If the paper is damaged in this way, it may take a lot of time and labor for the user to process the jammed paper.

  In Patent Document 1, an open / close detection sensor indicates that a cover once opened to handle a jam is closed for the purpose of preventing further damage of the sheet due to the drawer of the paper feed cassette. There has been proposed a technique for keeping the paper tray (paper cassette) locked until it is detected. However, when the cover is closed, even if jammed paper remains on the paper feeder, the lock is released. As a result, a state in which the paper feeding cassette is pulled out can occur, and when the paper feeding cassette is pulled out, the paper is further damaged.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that reliably prevents further breakage of jammed paper and guides a user to perform appropriate jam processing. .

  According to the first aspect of the present invention, the paper stored in a stacked state in a paper storage body configured to be drawable from the apparatus main body is intermittently fed out from the paper storage body in a direction crossing the pulling direction. An image forming apparatus that transports a fed sheet to a predetermined image forming position while being nipped by a conveying member provided on a sheet conveying path, and forms an image on the sheet. Jam detection means for detecting the occurrence of a jam on the paper, restriction means configured to be able to restrict movement of the paper container, and when the occurrence of jam is detected by the jam detection means, the restriction means And a restriction control means for restricting the movement of the paper container.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the transport member includes a transport member that sandwiches and transports the paper being fed from the paper storage body, and the transport member is exposed. An opening / closing door configured to be possible is provided.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the image forming apparatus further comprises an operation unit for inputting an instruction to release the movement restriction of the sheet storage body by the restriction unit, and the restriction control. The means is configured to release the movement restriction of the sheet storage body by the restriction means when an instruction to release the movement restriction is input by the operation means.

  According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the jam detection unit includes a sheet detection unit that detects the presence of a sheet at a predetermined detection position, Judgment that a jam has occurred on the paper when the output time of the signal indicating the presence is longer than the time calculated using the length of the paper in the transport direction and the paper transport speed Means.

  According to the first aspect of the present invention, when the jam occurs, the drawer of the paper storage body is restricted. Therefore, when the jam occurs, the paper storage body is pulled out, so that the paper storage body being fed out from the paper feed cassette It is possible to reliably and surely prevent the jammed paper from being further damaged and the jam processing being further troublesome. In addition, when the paper is fed out from the paper container while the paper fed out prior to the paper is being fed from the paper container, the paper is jammed even when a jam occurs in the preceding paper. Included in the concept of paper.

  According to the second aspect of the present invention, the user can be guided to an appropriate jam processing by opening the door.

  According to the third aspect of the present invention, the operation means for inputting an instruction to release the movement restriction of the paper container by the restriction means is provided, and when the movement restriction release instruction is input by the operation means, the paper is Since the movement restriction of the storage body is released, even if the jammed paper is further damaged due to the paper storage body being pulled out, some abnormality in the apparatus that requires the paper storage body to be pulled out has occurred. In this case, it is possible to allow the user to handle the abnormality in the apparatus by allowing the paper container to be pulled out.

  According to the fourth aspect of the present invention, the output time of the presence detection signal output by the paper detection means for detecting the presence of the paper at the predetermined detection position is the length in the paper transport direction, the paper transport speed, Since it is determined that a jam has occurred on the paper when the time calculated by using is longer than the time, the occurrence of the jam can be reliably detected.

  Hereinafter, an embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a front view showing an internal configuration of the image forming apparatus according to the present embodiment. In FIG. 1, the front and left and right sides are referred to as the front and left and right sides of the image forming apparatus.

  As shown in FIG. 1, the image forming apparatus 1 includes an image reading unit 2, an image forming unit 3, and a paper supply unit 4 in order from the top.

  The image reading unit 2 includes a document reading unit 5 including a CCD (Charge Coupled Device) sensor and an exposure lamp configured to be movable left and right, a document table 6 formed of a transparent member such as glass, and the front side facing upward. And an open / close lid 7 rotatably supported by the apparatus body so that the CCD sensor is relatively positioned along the original surface of the original placed on the original table 6. The original image is converted into an image signal for each line and captured. The image reading unit 2 performs predetermined signal processing (level correction, γ correction, A / D conversion, etc.) on the sequentially captured image signals, and then outputs them to a control unit 34 (see FIG. 5) described later.

  The image forming unit 3 outputs a laser beam or the like based on the image signal acquired by the image reading unit 2 and exposes the photosensitive drum 8, and a developing unit that forms a toner image on the photosensitive drum 8. 10, a transfer unit 11 that transfers the toner image on the photosensitive drum 8 to a sheet, a fixing unit 12 that fixes the toner image to the sheet by heating the sheet to which the toner image has been transferred, A conveyance roller 14 is provided in the sheet conveyance path and conveys the sheet to the document discharge unit 13.

  An operation unit 15 is provided at an appropriate position on the front side of the image forming apparatus 1. The operation unit 15 includes various buttons 16 and numeric keys 17 for inputting a print execution instruction, the number of copies to be printed, a liquid crystal display having a touch panel function for displaying various operation guide information and setting input for image forming operations, and the like. And a display unit 18 comprising:

  The sheet supply unit 4 includes a sheet feeding cassette 19 that stores a plurality of sheets P in a stacked state, and the sheet P in the sheet feeding cassette 19 is moved to the sheet P side by an unillustrated biasing mechanism including a spring or the like. The uppermost sheet P is fed from the right side to the left side one by one by the rotating operation of the biased paper feed roller 20. The paper supply unit 4 is transported to a predetermined position of the image forming unit 3 by the transport rollers 24 to 26, and a toner image formed on the surface of the photosensitive drum 8 described later is aligned with the leading end position of the paper P. Then, the sheet is conveyed between the photosensitive drum 8 and the transfer unit 11 after the conveyance timing is set. The paper feed cassette 19 is configured such that the paper P can be replenished by being pulled out from the apparatus main body 1a from the back side to the front side in FIG. The paper feed cassette 19 and the transport rollers 24 to 26 are examples of a sheet storage body and a transport member in the claims.

  As shown in FIGS. 1 and 2, an opening / closing cover 27 that can be opened and closed in a state where the lower end of the sheet supply unit 4 is pivotally supported by the apparatus main body 1a is provided on one side of the sheet supply unit 4. For example, when the paper P is jammed when the paper P is nipped by the transport roller 24 (denoted as jammed paper P ′ in FIG. 2), the opening / closing cover 27 is opened and the transport roller 24 is set to the outside. By exposing it, the jammed paper can be easily removed. Hereinafter, the removal operation of jammed paper is referred to as jam processing. The opening / closing cover 27 corresponds to the opening / closing door of the claims.

  The opening / closing cover 27 and the apparatus main body 1a are configured with an opening / closing detection mechanism 28 for detecting opening / closing of the opening / closing cover 27. Although not shown in detail, the open / close detection mechanism 28 includes, for example, a pair of light emitters / receivers installed opposite to the apparatus main body 1a and a light shielding member installed at an appropriate position of the open / close cover 27. When 27 is opened, light is transmitted and received between the projector and the light receiver. When the open / close cover 27 is closed, the light shielding member is configured to block the transmission and reception of the light. When the control unit 34 described later detects that the opening / closing cover 27 is opened based on the output signal of the light receiver, the control unit 34 determines that the jam processing is started, and detects that the opening / closing cover 27 is closed, It is determined that the processing has been completed.

  The jammed paper detection sensor 29 includes a light emitting element and a light receiving element arranged in an opposed state, and is installed at a plurality of positions on the paper conveyance path. The light emitting element is composed of, for example, a light emitting diode, and the light receiving element is composed of, for example, a phototransistor. When light output from the light emitting element is received by the light receiving element, an H (high) signal is output from the light receiving element, and when light from the light emitting element to the light receiving element is blocked, L ( Low) signal is output.

  When the jam does not occur, the paper P is intermittently conveyed from the paper feed cassette 19, so that the paper P passes between the light emitting element and the light receiving element as shown in FIG. A low period T1 (time t1) and an H (high) period T2 (time t2) until the next sheet is conveyed between the light emitting element and the light receiving element are periodically generated. The time t1 is a value determined according to the length of the paper P in the transport direction and the transport speed of the paper P. On the other hand, when the jam occurs, the paper P stays between the light emitting element and the light receiving element for the time t1 or more, so that a signal of a period L (low) of the time t1 or more is output from the light receiving element.

  Based on this, the control unit 34, which will be described later, determines that a jam has not occurred when the signal shown in FIG. 3 (a) rising from high to low after time t1 from the falling timing from high to low is received. When a signal shown in FIG. 3B that does not rise from high to low even when time t1 elapses from the falling timing from high to low, it is determined that a jam has occurred.

  In particular, in this embodiment, a jammed paper detection sensor 29 is provided in the vicinity of the paper outlet of the paper feed cassette 19 and in the vicinity of the transfer roller 24, and based on the output signal of the sensor 29, Not only the presence or absence of a jam in the vicinity but also whether or not the paper P is being fed out from the paper feed cassette 19 can be detected. The jammed paper detection sensor 29 is an example of a paper detection means in the claims.

  By the way, as described above, the image forming apparatus 1 can easily perform jam processing by opening the opening / closing cover 27 when a jam occurs on the paper P being fed from the paper feed cassette 19 at or near the transport roller 24. However, depending on the user, without knowing such a configuration, the user may try to remove the jammed paper by pulling out the paper feed cassette 19 when a jam occurs.

  Further, the sheet transported prior to the sheet P being fed out from the sheet feeding cassette 19 (preceding sheet), for example, a sheet conveying path between the image forming unit 3 and the sheet discharging unit 13 or the like, the conveying roller 24 or its When a jam occurs at a position other than the vicinity position, the conveyance of all the sheets P including the feeding out of the sheet P from the sheet feeding cassette 19 is stopped, so that the sheet P sandwiched between the conveyance rollers 24 is removed. Alternatively, there may be a case where the paper P being fed out from the paper feed cassette 19 is to be removed by pulling out the paper feed cassette 19.

  However, when the paper P has already been fed out from the paper cassette 19 halfway when the paper cassette 19 is pulled out, one end side of the paper P is sandwiched by the transport roller 24 while the other end side is the paper cassette. Since the sheet 19 is pulled along with the drawing 19, a part or all of the paper P being fed may be torn off. When such a situation occurs, the jam processing becomes troublesome, and extra time and labor are consumed.

  Therefore, in the present embodiment, in order to prevent the occurrence of such a situation, when a jam occurs while the paper P is being fed from the paper feed cassette 19, the movement of the paper feed cassette 19 is restricted and the user feeds it. The paper cassette 19 is prohibited from being pulled out.

  In order to realize the above-described configuration, the image forming apparatus 1 of the present embodiment includes a lock mechanism 30 described below. The lock mechanism 30 is an example of a restricting unit in the claims.

  FIG. 4 is a plan view illustrating a configuration example of the lock mechanism 30. The lock mechanism 30 is installed on the right side of the paper feed cassette 19, for example. As shown in FIG. 4, the solenoid 31 and the arm 32 installed in the apparatus main body 1 a and the engagement formed in the paper feed cassette 19. And a hole 19a. The arrangement position of the lock mechanism 30 is not limited to the right side of the paper feed cassette 19 and may be anywhere.

  The arm 32 is an L-shaped member that is pivotally supported by the support shaft O at a substantially central portion thereof, and one end portion of the arm main body 32a is rotatably attached to the solenoid shaft 31a. The other end is formed so as to protrude from the arm main body 32a substantially vertically toward the sheet feeding cassette 19 side.

  In the lock mechanism 30 having such a configuration, when the solenoid shaft 31a protrudes by the operation of the solenoid 31, the other end of the arm 32 engages with an engagement hole 19a formed in the right side wall of the sheet feeding cassette 19, While the drawer (movement in the direction indicated by arrow A) of the sheet cassette 19 is restricted (locked), when the solenoid shaft 31a is retracted, the engagement between the arm 32 and the engagement hole 19a of the sheet cassette 19 is released. The paper cassette 19 can be pulled out.

  Returning to FIG. 1, in this embodiment, in addition to the jammed paper detection sensor 29 and the lock mechanism 30 described above, a release button 33 for inputting an instruction to unlock the lock mechanism 30 to the operation unit 15. The lock mechanism 30 is unlocked by pressing the release button 33. The display unit 18 may be provided with a virtual release button, not limited to the form in which the release button 33 is provided using a predetermined member. The release button 33 is an example of an operation unit in the claims.

  Such a release button 33 is provided because, for example, the open / close cover 27 is opened to remove the jammed paper, but all the jammed paper cannot be removed and the remaining jammed paper remains on the paper feed cassette 19. Thus, when a situation occurs in which the remaining jammed paper must be removed by pulling out the paper feed cassette 19, or when the paper feed cassette 19 is pulled out, the jammed paper is further damaged. This is also in order to allow the user to cope with any abnormality that needs to be pulled out.

  Next, the electrical configuration of the image forming apparatus 1 will be described. FIG. 5 is a block diagram showing an electrical configuration of the image forming apparatus 1.

  The image reading unit 2, the image forming unit 3, the paper supply unit 4, the open / close detection mechanism 28, the jammed paper detection sensor 29, and the lock mechanism 30 illustrated in FIG. 3 corresponds to the paper supply unit 4, the open / close detection mechanism 28, the jam paper detection sensor 29, and the lock mechanism 30, and each has the above-described configuration.

  The control unit 34 controls the overall operation of the image forming apparatus 1. For example, a ROM (Read Only Memory) that stores a control program for controlling the operation of the image forming apparatus 1 and temporarily stores data. A memory unit (not shown) including a RAM (Random Access Memory) and the like, and a microcomputer that reads a control program and the like from the ROM and executes the program are executed.

  Further, the control unit 34 functionally includes a jam occurrence determination unit 35, a lock control unit 36, and a jam processing completion determination unit 37 in order to execute the lock processing as described above. The jam occurrence determination unit 35 and the lock control unit 36 correspond to determination means and restriction control means in the claims.

  The jam occurrence determination unit 35 determines whether or not a jam has occurred and whether or not the paper P is being fed out from the paper feed cassette 19 based on an output signal from the jam paper detection sensor 29. That is, when receiving the signal shown in FIG. 3A (a signal that periodically switches between high and low), it is determined that no jam has occurred, and the signal shown in FIG. When a signal (low continues for time t1 or more) is received, it is determined that a jam has occurred. Further, while the low signal is output from the jammed paper detection sensor 29 disposed in the vicinity of the outlet of the paper feed cassette 19, it is determined that the paper P is being fed out from the paper feed cassette 19. Signals indicating these determination results are output to the lock control unit 36.

  When it is determined by the jam occurrence determination unit 35 that no jam has occurred, the lock control unit 36 does not operate the solenoid 31 of the lock mechanism 30 and permits the movement of the paper feed cassette 19 while determining whether a jam has occurred. When it is determined by the section 35 that a jam has occurred, the solenoid 31 is activated to restrict the movement of the paper feed cassette 19.

  Further, when the release button 33 is pressed, the lock control unit 36 activates the solenoid 31 to release the movement restriction of the paper feed cassette 19.

  The jam processing completion determination unit 37 determines whether or not the jam processing is completed based on signals output from the open / close detection mechanism 28 and the jam paper detection sensor 29 after the occurrence of the jam. That is, when the jam processing is completed, a high signal is output from the jam paper detection sensor 29, and the closing signal is output after the opening signal is output from the open / close detection mechanism 28. The completion determination unit 37 determines that the jam processing has been completed. On the other hand, if the signals output from the open / close detection mechanism 28 and the jam paper detection sensor 29 are other than that, it determines that the jam processing has not been completed. To do.

  Note that a program that causes the control unit 34 to function as the jam occurrence determination unit 35, the lock control unit 36, and the jam processing completion determination unit 37 can be supplied through a recording medium such as a ROM or a CD-ROM, a communication line, or the like. It is also possible to supply through the transmission medium.

  FIG. 6 is a flowchart showing the lock processing of the image forming apparatus 1 according to the present invention.

  As shown in FIG. 6, the jam occurrence determination unit 35 determines whether a jam has occurred on the paper conveyance path from the paper feed cassette 19 to the paper discharge unit 13 based on the output signal of the jam paper detection sensor 29. (Step # 1). If a jam has not occurred (NO in step # 1), the control unit 34 does not perform the process shown in the flowchart of FIG. When the jam occurrence determination unit 35 determines that a jam has occurred (YES in step # 1), the paper feed cassette is based on the output signal from the jam paper detection sensor 29 disposed in the vicinity of the paper feed cassette 19. From step 19, it is determined whether or not the sheet is being fed out (step # 2).

  As a result, when the sheet is being fed out from the sheet feeding cassette 19 (YES in step # 2), the lock control unit 36 causes the lock mechanism 30 to perform a locking operation (step # 3). Thereby, the movement of the paper feed cassette 19 is restricted. As a result, the user knows that the sheet cassette 19 cannot be pulled out, and is guided to the jam processing by opening the opening / closing cover 27.

  The jam processing completion determination unit 37 detects a state where the opening / closing cover 27 is not yet opened, or a state where the opening / closing cover 27 is opened but the opening / closing cover 27 is not closed (step # 4). NO), the process returns to step # 1, and when it is detected that the open / close cover 27 is closed (YES in step # 4), the lock control unit 36 releases the lock operation by the lock mechanism 30 (step # 5).

  As described above, when a jam occurs while the paper is being fed out from the paper feed cassette 19, the movement of the paper feed cassette 19 is restricted. It is possible to reliably and reliably prevent the paper from being further damaged and troublesome jam processing.

  Further, since the operation unit 15 is provided with a release button 33 for inputting an instruction to release the lock by the lock mechanism 30, even if the jammed paper is further damaged by pulling out the paper feed cassette 19, the paper is fed. When some abnormality that requires the paper cassette 19 to be pulled out occurs, it is possible to deal with the abnormality.

  The present invention is not limited to the above-described embodiment, and for example, the following modifications (1) and (2) can be adopted.

  (1) When a plurality of paper feed cassettes 19 are provided in accordance with the size of the paper, a jam paper detection sensor 29 and a lock mechanism 30 are provided corresponding to each paper feed cassette 19, and one of the paper feed cassettes 19 is provided. The movement of the paper feed cassette 19 may be regulated while the paper is being fed from the paper cassette 19.

  (2) The image forming apparatus includes all apparatuses for forming an image on a sheet such as a facsimile, a printer, a copier, etc. The present invention can be applied to all of them.

1 is a front view illustrating an internal configuration of an image forming apparatus according to an embodiment of the present invention. It is a figure for demonstrating operation | movement of an opening / closing cover. (A) is a diagram showing an output signal from a jammed paper detection sensor when no jammed paper is generated, and (b) is a diagram showing an output signal from a jammed paper detection sensor when a jammed paper is generated. is there. It is a top view which shows one structural example of a locking mechanism. 1 is a block diagram illustrating an electrical configuration of an image forming apparatus. 6 is a flowchart illustrating a lock process of the image forming apparatus. It is a figure which shows schematic structure of the conventional image forming apparatus.

Explanation of symbols

19 Paper feeding cassette 24 Conveying roller 27 Opening / closing cover 28 Opening / closing detection mechanism 29 Jam paper detection sensor 30 Lock mechanism 33 Release button 35 Jam occurrence determination unit 36 Lock control unit 37 Jam processing completion determination unit

Claims (4)

The paper stored in a stacked state in a paper storage body configured to be drawable from the apparatus main body is intermittently paid out from the paper storage body in a direction crossing the pulling direction, and the supplied paper is provided on the paper transport path. An image forming apparatus that conveys to a predetermined image forming position while being held by a conveyed member and forms an image on the paper,
A jam detecting means for detecting that a jam has occurred in the paper being fed out of the paper container;
Restriction means configured to be capable of restricting movement of the paper container;
An image forming apparatus comprising: a regulation control unit that causes the regulation unit to regulate movement of the sheet storage body when occurrence of a jam is detected by the jam detection unit.   The said conveyance member is provided with the opening-and-closing door comprised so that the conveyance member may be exposed, including the conveyance member which clamps and conveys the sheet | seat being drawn | fed out from the said paper storage body. Image forming apparatus.   Operation means for inputting an instruction to release the movement restriction of the paper container by the restriction means, and the restriction control means, when the movement restriction release instruction is input by the operation means, the restriction means The image forming apparatus according to claim 1, wherein the movement restriction of the sheet storage body is released. The jam detection means includes a paper detection means for detecting the presence of paper at a predetermined detection position, and an output time of a signal indicating that the presence of the paper has been detected. 4. The image forming apparatus according to claim 1, further comprising: a determination unit configured to determine that a jam has occurred on the paper when the time calculated by using the above is longer.

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