JP2014012584A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus which: reliably detects that a lid body is not in a state in which it fully closes an opening of a housing; and realizes such reliable detection while suppressing increase in the manufacturing cost.SOLUTION: In an image forming apparatus 1, the open/closed state of a cover 32 of a housing 2 is detected by using an opening/closing detection switch and a distance measurement sensor 21. The distance measurement sensor 21 is arranged in a position facing a conveyance path 8 originally for detecting a deflection amount of a sheet passing the conveyance path 8. By using this distance measurement sensor 21, the distance between a conveyance mechanism body 41 and a separation unit 42 is measured. When the cover 32 is opened or when the cover 32 is partially closed, the distance between the conveyance mechanism body 41 and the separation unit 42 becomes greater than a prescribed distance. Thus, based on a measurement result of the distance measurement sensor 21, a state in which the cover 32 is open or a state in which it is partially closed can be detected.

Description

  The present invention relates to an image forming apparatus such as a printing apparatus, a copying apparatus, or a multifunction peripheral.

  In general, in a housing of an image forming apparatus such as a printing apparatus, a copying apparatus, or a multifunction peripheral, a printing mechanism that forms an image and prints an image on a sheet, a sheet storage unit (for example, a paper feed cassette) that stores the sheet, A paper discharge unit (for example, a discharge tray) that discharges paper on which an image is printed, a transport mechanism that transports the paper from the paper storage unit to the printing mechanism, and transports the paper on which the image has been printed to the paper discharge unit, and the like Is provided.

  Further, in a general image forming apparatus, an opening is formed in a part of the casing (for example, a side wall), and the casing is provided with a lid that opens and closes the opening. Further, in many image forming apparatuses, the conveyance mechanism is divided into a case side unit fixed to the case side and a cover side unit fixed to the cover side with a conveyance path through which the sheet is conveyed as a boundary. Then, when the lid is swung or slid with respect to the housing to open the opening, the lid body side unit is separated from the housing side unit along with the lid, and a portion serving as a conveyance path is exposed to the outside. (For example, refer patent document 1). In this manner, the user can move the lid to open the opening of the housing and expose the portion that becomes the conveyance path to the outside. Thereby, when the paper is jammed in the transport path, the user can easily remove the paper and can easily perform maintenance and repair of the transport mechanism and the printing mechanism.

  Many image forming apparatuses are provided with an open / close detection switch for detecting the open / closed state of the opening by the lid (see, for example, Patent Document 1 or 2). Normally, one open / close detection switch is arranged on a part of the periphery of the opening, and when the lid closes the opening, it is pushed by the lid to turn on, and the lid opens the opening. When you are away from the lid, it turns off.

  If the opening is opened and the part that becomes the conveyance path is exposed to the outside, the printing process or the like cannot be normally performed in the image forming apparatus. In order to perform a printing process or the like normally, the opening must be completely closed, the lid side unit approaches the casing side unit, and both units must be arranged in a predetermined positional relationship. For this reason, many image forming apparatuses detect the opening / closing state of an opening by an opening / closing detection switch, and when the opening is closed according to the detection result of the opening / closing detection switch, in response to an instruction input from a user, etc. When the execution of the printing process is permitted and the opening is open, the execution of the printing process is prohibited regardless of the instruction input from the user.

JP 2009-179441 A JP 2008-160491 A

  By the way, in the conventional image forming apparatus, although the lid partially closes the opening of the housing, it is not completely closed, that is, it is in a semi-closed state and is in a semi-closed state. Sometimes the open / close detection switch is turned on. In this case, since the image forming apparatus detects the opening / closing state of the opening only by turning on / off the opening / closing detection switch, the opening is closed as long as the opening / closing detection switch is on even in the half-closed state. It will be judged. Also, in many cases, the user is not aware that the user is in a semi-closed state, and misidentifies that the lid is completely closed. For this reason, in spite of the semi-closed state, the user inputs an instruction to start the printing process to the image forming apparatus, and the image forming apparatus may execute the printing process accordingly. is there.

  As described above, in order to perform the printing process or the like normally, the opening is completely closed, and the lid-side unit and the housing-side unit constituting the transport mechanism are arranged in a predetermined positional relationship. Must. However, in the semi-closed state, the lid-side unit and the housing-side unit may not have a predetermined positional relationship. For example, the lid side unit is not sufficiently close to the casing side unit. For this reason, the transfer roller (or transport roller) provided in the lid side unit and the drive roller (or transport roller) provided in the casing side unit. There may be a case where the contact with is not sufficiently secured. As a result, if the printing process is executed in a semi-closed state, the printing process may not be performed normally and a paper jam may occur.

  In the semi-closed state, the lid body may not be sufficiently supported by the housing. In this case, the lid body may vibrate greatly due to the operation of the image forming apparatus. This vibration is transmitted to the printing mechanism. As a result, the print image is distorted, and the quality of the print image may be deteriorated.

  On the other hand, in many conventional image forming apparatuses, the number of open / close detection switches is one, and the position where the open / close detection switch is provided is often the peripheral portion on one side (left side or right side) of the opening. . For this reason, if one side of the lid is in the closed position, the open / close detection switch may be turned on even if the opposite side of the lid is not in the closed position. It is thought that it cannot be done. Therefore, if the number of open / close detection switches is set to two and these open / close detection switches are respectively arranged at a plurality of positions (for example, the left side and the right side) of the periphery of the opening, it seems that the semi-closed state can be detected reliably. is there. However, increasing the number of open / close detection switches is not desirable because it increases the manufacturing cost of the image forming apparatus.

  The present invention has been made in view of, for example, the above-described problems, and an object of the present invention is to reliably detect that the lid body is not in a state of completely closing the opening of the housing, and to perform such reliable detection. An object of the present invention is to provide an image forming apparatus capable of realizing the above while suppressing an increase in manufacturing cost.

  In order to solve the above problems, a first image forming apparatus of the present invention closes the opening by contacting or approaching the box-shaped housing having an opening, and the housing. A lid that opens the opening by moving away from the paper, a paper supply unit that is provided in the housing and supplies paper, an image forming unit that is provided in the housing and forms an image, and is provided in the housing. A transfer unit that transfers the image formed by the image forming unit to the paper supplied by the paper supply unit; a fixing unit that is provided in the housing and fixes the image transferred by the transfer unit to the paper; A paper discharge unit that discharges the paper on which an image is fixed by the fixing unit, and a conveyance path through which the paper moves from the paper supply unit to the paper discharge unit via the transfer unit and the fixing unit; For use in the transport path And a distance measuring sensor that detects the state of the paper by measuring the distance between the paper and the paper that moves along the paper path, and the transport mechanism. Includes a transport mechanism main body and a separation unit separable from the transport mechanism main body with the transport path as a boundary, and the separation unit is separated from the transport mechanism main body when the lid closes the opening. The transport path is formed close to the transport mechanism main body so as to maintain a predetermined distance, and when the lid opens the opening, the lid separates from the casing. An image forming apparatus separated from the transport mechanism main body, wherein a distance between the transport mechanism main body and the separation unit is detected by the distance measuring sensor, and the opening and closing of the opening by the lid based on the detection result State Characterized in that it comprises a closing judging section for disconnection.

  According to the first image forming apparatus of the present invention, the distance between the transport mechanism main body and the separation unit is detected by the distance measuring sensor, and the opening / closing state of the opening by the lid is determined based on the detection result. It is possible to reliably detect that the lid is not in a state of completely closing the opening of the housing. Further, since the distance measuring sensor is conventionally provided in the image forming apparatus to detect the state of the sheet moving on the conveyance path, it is necessary to reliably detect the completely closed state of the lid. Therefore, the number of parts does not increase, and therefore an increase in manufacturing cost of the image forming apparatus can be suppressed.

  In order to solve the above problems, a second image forming apparatus of the present invention is provided between the casing and the lid in the first image forming apparatus of the present invention described above, and the lid is When the opening is closed, it is pushed by the lid or the casing to be turned on, and when the lid is opening the opening, the lid is separated from the casing or the casing to be turned off. The open / close determining unit detects when the distance sensor detects that the distance between the transport mechanism main body and the separation unit is the predetermined distance, and the switch is on. It is determined that the opening is closed by the lid.

  According to the second image forming apparatus of the present invention, since the open / closed state of the lid is detected by both the distance measuring sensor and the switch, the lid is not in a state of completely closing the opening of the housing. Can be detected more reliably.

  In order to solve the above-described problem, a third image forming apparatus according to the present invention is the above-described first or second image forming apparatus according to the present invention, wherein the distance measuring sensor is connected to a sheet moving along the conveyance path. The amount of bending of the paper is detected by measuring the distance between them.

  According to the third image forming apparatus of the present invention, the distance between the separation unit and the transport mechanism main body can be detected with high accuracy by the distance measuring sensor that detects the amount of deflection of the sheet moving on the transport path. . Thereby, it can be detected with high accuracy that the lid is not in a state of completely closing the opening of the housing.

  According to the present invention, it can be reliably detected that the lid is not in a state of completely closing the opening of the housing, and such reliable detection can be realized while suppressing an increase in manufacturing cost.

1 is an explanatory diagram illustrating an internal structure of an image forming apparatus according to an embodiment of the present invention. 1 is a perspective view illustrating an appearance of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is an explanatory diagram showing a part of a conveyance path, a part of a conveyance mechanism, a transfer unit, a distance measuring sensor, and the like inside the image forming apparatus according to the embodiment of the present invention. It is explanatory drawing which shows the structure of the ranging sensor provided in the image forming apparatus by embodiment of this invention. FIG. 3 is an explanatory diagram illustrating a state in which a cover of the image forming apparatus according to the embodiment of the present invention is opened. 1 is an external view showing a state where a cover of an image forming apparatus according to an embodiment of the present invention is opened. FIG. 6 is an explanatory diagram illustrating an operation of measuring a distance between a transport mechanism main body and a separation unit by a distance measuring sensor provided in the image forming apparatus according to the embodiment of the present invention. 5 is a flowchart illustrating open / close determination processing in the image forming apparatus according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 schematically shows the internal structure of an image forming apparatus according to an embodiment of the present invention. FIG. 2 shows the appearance of the image forming apparatus in FIG. FIG. 3 shows the inside of the image forming apparatus in FIG. 1 and shows a part of the transport path, a part of the transport mechanism, a transfer unit, a distance measuring sensor, and the like. FIG. 4 schematically shows the structure of the distance measuring sensor in FIG.

  In FIG. 1, an image forming apparatus 1 according to an embodiment of the present invention is a multi-function machine having a printing function, a copying function, a facsimile function, and the like. The image forming apparatus 1 includes a box-shaped housing 2. In the housing 2, an image forming unit 3 that forms an image, a transfer unit 4 that transfers an image onto a sheet, and an image transferred onto the sheet are fixed. A fixing unit 5 is provided.

  The image forming apparatus 1 employs a tandem color laser printing method, and the image forming unit 3 includes a driving roller 3A, a driven roller, a transfer belt, and a belt cleaning device, and further, black, cyan, yellow, magenta For each of the four colors, a photosensitive drum, a charging device, an exposure device, a developing device, a drum cleaning device, a primary transfer roller, a toner storage portion, and the like are provided for each color. The transfer unit 4 includes a secondary transfer roller 4A that transfers a color toner image formed on the transfer belt onto a sheet.

  In the housing 2, a plurality of paper feed cassettes 6 serving as paper supply units are provided below the image forming unit 3, and paper is stored in each paper feed cassette 6. In the housing 2, a discharge tray 7 is provided above the image forming unit 3 as a paper discharge unit for discharging the paper on which the image is fixed.

  In the housing 2, a conveyance path 8 is formed in which the paper drawn from each paper feed cassette 6 moves to the discharge tray 7 via the transfer unit 4 and the fixing unit 5. Further, a transport mechanism for moving the paper in the transport path 8 is provided in the housing 2. The transport mechanism includes a paper feed roller unit 15 that pulls out paper from each paper feed cassette 6, a transport roller unit 16 that sequentially transports paper drawn from each paper feed cassette 6 to the transfer unit 4 and the fixing unit 5, and a fixing unit 5. A discharge roller unit 17 and the like for conveying the passed paper to the discharge tray 7 are provided. The paper feed roller unit 15 is provided for each paper feed cassette 6, and each paper feed roller unit 15 has a plurality of paper feed rollers. One or more transport roller units 16 are arranged near the transfer unit 4 or the fixing unit 5 in the transport path 8, and each transport roller unit 16 has a pair of transport rollers 16A and 16B facing each other. One or more discharge roller units 17 are arranged in the transport path 8 from the downstream side of the fixing unit 5 to the discharge tray 7, and each discharge roller unit 17 has a pair of discharge rollers facing each other. .

  A distance measuring sensor 21 is provided in the vicinity of the conveyance path 8 in the housing 2. The distance measuring sensor 21 is disposed at a position facing the conveyance path 8. In the present embodiment, as shown in FIG. 3, the distance measuring sensor 21 is positioned on the inner side of the housing 2 with respect to the transport path 8 and on the upstream side of the transport roller unit 16 positioned on the upstream side of the transfer unit 4. Is arranged. Further, the distance measuring sensor 21 is disposed at a position corresponding to a substantially intermediate position in the front-rear direction of the image forming apparatus 2 in the conveyance path 8. The distance measuring sensor 21 detects the state of the paper by measuring the distance to the paper moving on the transport path 8. More specifically, the distance measuring sensor 21 detects the amount of bending of the sheet by measuring the distance from the sheet moving on the conveyance path 8. For example, the rotation speed of the transport roller unit 16 is controlled based on the detected amount of deflection of the paper. Thereby, the bending of the paper is removed.

  As shown in FIG. 4, the distance measuring sensor 21 includes a light emitting unit 22, a light receiving unit 23, a light projecting lens 24, a light receiving lens 25, a drive circuit 26, and a distance calculating circuit 27. The light emitting unit 22 is, for example, an infrared light emitting diode, and the light receiving unit 23 is, for example, a PSD element (optical position sensor element). The drive circuit 26 controls the light emission of the light emitting unit 22. The light emitted from the light emitting unit 22 is collected by the light projecting lens 24 and projected onto the paper P. The light reflected on the paper P is collected by the light receiving lens 25 and enters the light receiving unit 23. The distance calculation circuit 27 outputs a distance measurement signal whose voltage changes corresponding to the barycentric position of the amount of light incident on the light receiving unit 23. The distance measurement signal is input to a CPU (Central Processing Unit) provided in the control circuit unit 11 described later. The CPU calculates the amount of bending of the paper P based on the distance measurement signal, and controls the rotation speed of the transport roller unit 16 based on the calculated amount of bending. Further, the CPU determines the open / closed state of the cover 32 described later based on the distance measurement signal and the open / close detection signal described later.

  As shown in FIG. 1, an image reading mechanism 9 for reading an image from a document is provided above the image forming unit 3 in the housing 2, and the image reading mechanism 9 includes a scanner and the like. As shown in FIG. 2, an operation unit 10 having operation keys, a display, and the like is provided above the housing 2. Further, as shown in FIG. 1, a control circuit unit 11 that controls the operation of the image forming apparatus 1 is provided in the housing 2, and the control circuit unit 11 includes a CPU (Central Processing Unit), a memory, a communication A control circuit and the like are provided. As will be described later, the CPU of the control circuit unit 11 functions as an open / close determining unit that determines the open / closed state of the cover 32 using the distance measuring sensor 21 and the open / close detection switch 36.

  FIG. 5 schematically shows a state where the cover 32 of the image forming apparatus 1 is opened. FIG. 6 shows the appearance of the image forming apparatus 1 with the cover open.

  As shown in FIG. 5, an opening 31 is formed in the side wall 2 </ b> A of the housing 2 to enable the paper jam to be eliminated and the image forming apparatus 1 to be maintained. Further, a cover 32 as a lid that covers the opening 31 is attached to the side wall 2A. The cover 32 closes the opening 31 by contacting or approaching the housing 2 (see FIG. 1 or 2), and opens the opening 31 by moving away from the housing 2 (see FIG. 5 or 6). .

  As shown in FIG. 6, a support arm 33 is connected to each side portion of the cover 32, and a guide portion 34 that slidably supports each support arm 33 is provided on the housing 2 side. Further, a clue part 35 is provided on the surface side of the cover 32. The user or the like can open the cover 32 and open the opening 31 by placing the hand on the clue part 35 and pulling the cover 32 away from the housing 2. On the other hand, the user or the like can close the cover 32 and close the opening 31 by pushing the cover 32 in a direction approaching the housing 2.

  As shown in FIG. 6, on the housing 2 side, an opening / closing detection switch 36 is provided on a part of the periphery of the opening 31 (for example, the right periphery of the opening 31). When the cover 32 is closed, the edge of the back surface of the cover 32 comes into contact with the open / close detection switch 36, and the open / close detection switch 36 is pushed, whereby the open / close detection switch 36 is turned on. On the other hand, when the cover 32 is opened, the cover 32 is separated from the open / close detection switch 36, and the open / close detection switch 36 is not pressed, thereby turning the open / close detection switch 36 off. When the open / close detection switch 36 is pushed, an open / close detection signal (for example, a DC signal having a high level voltage VH) indicating that the open / close detection switch 36 is turned on is output from the open / close detection switch 36. . When the open / close detection switch 36 is not pressed, an open / close detection signal (for example, a DC signal having a low level voltage VL) indicating that the open / close detection switch 36 is turned off is output from the open / close detection switch 36. The The open / close detection signal is input to a CPU provided in the control circuit unit 11. The CPU determines the open / closed state of the cover 32 based on the open / close detection signal and the distance measurement signal described above.

  A part of the transport mechanism is fixed to the back side of the cover 32. That is, as shown in FIG. 5, the transport mechanism includes a transport mechanism main body 41 and a separation unit 42 that can be separated from the transport mechanism main body 41 with the transport path 8 as a boundary. The separation unit 42 is fixed to the back surface of the cover 32. In the present embodiment, for example, one of the secondary transfer roller 4 </ b> A and the conveyance roller unit 16 is attached to the separation unit 42, and the other components constituting the conveyance mechanism are attached to the conveyance mechanism body 41. ing.

  When the cover 32 is closed and the opening 31 is closed, the separation unit 42 is close to the transport mechanism main body 41 so as to maintain a predetermined distance D (see FIG. 7 (1)). A conveyance path 8 is formed between them. In a state where the distance between the transport mechanism main body 41 and the separation unit 42 is a predetermined distance D, the secondary transfer roller 4A comes into contact with the driving roller 3A with an appropriate pressing force, and the transport rollers 16A and 16B are appropriate to each other. Contact with pressing force.

  On the other hand, when the cover 32 is opened and the opening 31 is opened, the separation unit 42 moves away from the transport mechanism main body 41 as the cover 32 moves away from the housing 2. At this time, the distance between the transport mechanism main body 41 and the separation unit 42 is significantly larger than the predetermined distance D. When the distance between the transport mechanism main body 41 and the separation unit 42 is significantly larger than the predetermined distance D, the secondary transfer roller 4A is completely separated from the driving roller 3A, and the transport roller 16B is completely separated from the transport roller 16A. As shown in FIG. 6, when the separation unit 42 is pulled out together with the cover 32, a portion that becomes the conveyance path 8 is exposed to the outside. Thereby, when the paper is jammed in the transport path 8, the user or the like can easily remove the paper and can easily perform maintenance and repair of the transport mechanism, the image forming unit 3, and the like.

  FIG. 7 shows an operation in which the distance measuring sensor 21 measures the distance between the transport mechanism main body 41 and the separation unit 42. The distance measuring sensor 21 measures the distance between the sheet moving on the conveyance path 8 to measure the amount of bending of the sheet and the distance between the conveyance mechanism main body 41 and the separation unit 42. It has both functions. Here, the operation of measuring the distance between the transport mechanism main body 41 and the separation unit 42 by the distance measuring sensor 21 will be described with reference to FIG.

  As shown in FIG. 7 (1), when the cover 32 is closed, the separation unit 42 approaches the transport mechanism main body 41, and the distance a between the transport mechanism main body 41 and the separation unit 42 becomes the predetermined distance D. In this case, the light emitted from the light emitting unit 22 of the distance measuring sensor 21 is reflected on the surface of the separation unit 42, and the reflected light is input to the light receiving unit 23. As a result, a distance measurement signal having a voltage VD (for example, 3 volts) corresponding to the predetermined distance D is output from the distance calculation operation circuit 27 and input to the CPU of the control circuit unit 11. The CPU can recognize that the distance a between the transport mechanism main body 41 and the separation unit 42 is the predetermined distance D based on the distance measurement signal.

  On the other hand, as shown in FIG. 7B, when the cover 32 is opened, the separation unit 42 is separated from the transport mechanism main body 41, and the distance a between the transport mechanism main body 41 and the separation unit 42 is larger than the predetermined distance D. Significantly larger. In this case, since the separation unit 42 is located far away from the light emitting unit 22 of the distance measuring sensor 21, there is an object that reflects light emitted from the light emitting unit 22 and makes the reflected light enter the light receiving unit 23. No longer. For this reason, even if light is emitted from the light emitting unit 22, no detectable light is input to the light receiving unit 23. As a result, a distance measurement signal having a voltage V0 (for example, 0 volts) corresponding to infinity is output from the distance calculation circuit 27 and input to the CPU. The CPU can recognize that the distance a between the transport mechanism main body 41 and the separation unit 42 is larger than the predetermined distance D based on the distance measurement signal.

  On the other hand, as shown in FIG. 7 (3), when the cover 32 is in a semi-closed state and the opening 31 is partially closed but not completely closed, the transport mechanism main body 41 and the separation unit are separated. The distance “a” to 42 is greater than the predetermined distance “D”. In this case, the light emitted from the light emitting unit 22 of the distance measuring sensor 21 is reflected on the surface of the separation unit 42, but the reflected light travels to a position away from the light receiving unit 23 and is not input to the light receiving unit 23. As a result, a distance measurement signal having a voltage V0 corresponding to infinity is output from the distance calculation circuit 27 and input to the CPU. The CPU can recognize that the distance a between the transport mechanism main body 41 and the separation unit 42 is larger than the predetermined distance D based on the distance measurement signal.

  Further, as shown in FIG. 7 (4), even if the cover 32 is in a semi-closed state, the distance a between the transport mechanism main body 41 and the separation unit 42 may approach the predetermined distance D. In this case, light emitted from the light emitting unit 22 of the distance measuring sensor 21 and reflected on the surface of the separation unit 42 is input to the light receiving unit 23. However, in this case, a distance measurement signal having a voltage higher than the voltage VD corresponding to the predetermined distance D is output from the distance calculation circuit 27 and input to the CPU of the control circuit unit 11. The CPU can recognize that the distance a between the transport mechanism main body 41 and the separation unit 42 is larger than the predetermined distance D based on the distance measurement signal.

  In the state where the cover 32 is semi-closed, the distance between the transport mechanism main body 41 and the separation unit 42 is larger than the predetermined distance D, so the secondary transfer roller 4A and the driving roller 3A are in contact with each other. There may be a state in which there is no contact, or there is no appropriate pressing force between the two in contact. Similarly, when the cover 32 is semi-closed, the conveyance roller 16A and the conveyance roller 16B are not in contact with each other, or are in contact with each other but no appropriate pressing force is generated between them. There is.

  FIG. 8 shows an open / close determination process executed by the CPU provided in the control circuit unit 11. For example, the CPU executes the next open / close determination process at a constant cycle.

  In the opening / closing determination process shown in FIG. 8, the CPU acquires an opening / closing detection signal from the opening / closing detection switch 36 (step S1). For example, when the open / close detection switch 36 is on, the voltage is VH, and when the open / close detection switch 36 is off, the open / close detection signal is VL. Subsequently, the CPU determines whether or not the open / close detection switch 36 is on based on the acquired voltage of the open / close detection signal (step S2).

  When the open / close detection switch 36 is on (step S2: YES), the CPU subsequently acquires a distance measurement signal from the distance measuring sensor 21 (step S3). The distance measurement signal has a voltage VD when the distance between the transport mechanism main body 41 and the separation unit 42 is the predetermined distance D, and a voltage when the distance between the transport mechanism main body 41 and the separation unit 42 is not the predetermined distance D. Becomes a value other than VD. In particular, when the cover 32 is semi-closed, the distance between the transport mechanism main body 41 and the separation unit 42 is often much larger than the predetermined distance D. In this case, the voltage of the distance measurement signal is 0. Subsequently, the CPU determines whether the distance between the transport mechanism main body 41 and the separation unit 42 is a predetermined distance D based on the acquired voltage of the distance measurement signal (step S4).

  When the distance between the transport mechanism main body 41 and the separation unit 42 is the predetermined distance D (step S4: YES), the CPU permits execution of the printing process in the image forming apparatus 1 (step S5). In this case, when the user inputs an instruction to start execution of the printing process to the image forming apparatus 1, the image forming apparatus 1 executes the printing process accordingly.

  On the other hand, when the open / close detection switch 36 is off (step S2: NO) or when the distance between the transport mechanism main body 41 and the separation unit 42 is not the predetermined distance D (step S4: NO), the CPU performs image formation. Execution of the printing process in the apparatus 1 is prohibited (step S6). In this case, when the user inputs an instruction to start execution of the printing process to the image forming apparatus 1, the image forming apparatus 1 does not execute the printing process, for example, emits a warning sound to the user, Alternatively, a message for confirming whether or not the cover 32 is completely closed is displayed on the display of the operation unit 10.

  As described above, according to the image forming apparatus 1 of the embodiment of the present invention, the cover 32 is completely closed and the opening 31 of the housing 2 is completely closed using the open / close detection switch 36 and the distance measuring sensor 21. It is possible to reliably and accurately detect that the state has been achieved. As a result, since the printing process is executed with the cover 32 half-closed, it is possible to reliably prevent paper jams, malfunctions, and abnormal printing processes. Further, the image forming apparatus operates with the cover 32 being semi-closed, and thus the cover 32 vibrates greatly, and it is ensured that the distortion of the print image and the deterioration of the quality of the print image occur due to the vibration. Can be prevented.

  Further, by using the high-precision distance measurement capability of the distance measuring sensor 21, it is possible to improve the accuracy of detecting whether or not the cover 32 is completely closed as compared with the case where only the open / close detection switch 36 is used. . In addition, by using both the open / close detection switch 36 and the distance measuring sensor 21 that are arranged at different locations, the positional relationship between the cover 32 and the housing 2 can be detected at two locations. The semi-closed state can be reliably detected.

  Further, since the configuration is such that the open / closed state of the cover 32 is detected using the distance measuring sensor 21 provided in the image forming apparatus 1 in order to detect the amount of deflection of the paper in the transport path 8 as described above. A reliable and highly accurate detection of the closed state of the cover 32 can be realized while suppressing an increase in manufacturing cost or at a low cost.

  In the above-described embodiment, an example in which the open / close state of the cover 32 is detected using the open / close detection switch 36 and the distance measuring sensor 21 has been described as an example. However, the open / closed state of the cover 32 can be determined using only the distance sensor 21. It may be detected. However, the detection accuracy of the open / close state of the cover 32 can be improved by detecting the open / close state of the cover 32 using both the open / close detection switch 36 and the distance measuring sensor 21 as described above.

  In the above-described embodiment, the distance measuring sensor 21 is disposed at a substantially intermediate position in the front-rear direction of the image forming apparatus 2 (when the opening 31 is viewed from the front thereof, the opening / closing direction is substantially in the middle). Although the case where the switch 36 is disposed on the right peripheral edge of the opening 31 has been described as an example, the present invention is not limited to this. For example, when the opening / closing detection switch 36 is arranged at the right peripheral edge of the opening 31, the distance measuring sensor 21 is arranged on the left side of the intermediate position in the left-right direction of the opening 31, The sensors 21 may be further separated from each other. Alternatively, the open / close detection switch 36 may be disposed on the left peripheral edge of the opening 31, and the distance measuring sensor 21 may be disposed on the right side of the intermediate position in the left-right direction of the opening 31. By separating the distance measuring sensor 21 and the open / close detection switch 36 from each other, it is possible to improve the accuracy of detecting whether or not the cover 32 is completely closed.

  In the above-described embodiment, the case where the distance measuring sensor 21 is attached to the transport mechanism main body 41 on the housing 2 side is taken as an example, but the present invention is not limited to this. The distance measuring sensor 21 may be attached to the separation unit 42 on the cover 32 side. Further, the distance measuring sensor 21 may be disposed between the transfer unit 4 and the fixing unit 5, for example.

  In the above-described embodiment, the opening / closing detection switch 36 is pushed when the transport mechanism body 41 and the separation unit 42 approach each other, and the opening / closing detection is performed based on the opening / closing detection signal output in this state. On the other hand, when it is determined that the switch 36 is turned on, the open / close detection switch 36 is not pressed when the transport mechanism main body 41 and the separation unit 42 are separated from each other, and the open / close detection signal output in this state. The case where it is determined that the open / close detection switch 36 is turned off based on the above is taken as an example, but the present invention is not limited to this. When the transport mechanism main body 41 and the separation unit 42 approach each other, the open / close detection switch 36 is not pressed, and the open / close detection switch 36 is turned on based on the open / close detection signal output in this state. On the other hand, when the transport mechanism main body 41 and the separation unit 42 are separated from each other, the open / close detection switch 36 is pressed, and the open / close detection switch 36 is set based on the open / close detection signal output in this state. You may judge that it turned off. Further, the open / close detection switch 36 may be attached to the cover 32 side instead of the housing 2 side.

  In the above-described embodiment, the case where the present invention is applied to the image forming apparatus configured to open and close the opening 31 by sliding the cover 32 in the horizontal direction with respect to the housing 2 is described as an example. The present invention is not limited to this. The present invention can also be applied to an image forming apparatus configured to open and close the opening 31 by swinging or rotating the cover with respect to the housing 2. In the above-described embodiment, the case where the present invention is applied to the image forming apparatus having the configuration in which the separation unit 42 is fixed to the back surface of the cover 32 is described as an example, but the present invention is not limited thereto. A part of the separation unit is swingably or pivotably supported on the housing side. When the cover is closed, the separation unit is sandwiched between the cover and the transport mechanism body, and the separation unit is transported. Although the mechanism body and the mechanism body are in a predetermined positional relationship close to each other, when the cover is opened, the separation unit swings or pivots away from the transport mechanism body by its own weight, and the part that becomes the transport path is exposed to the outside. The present invention can also be applied to an image forming apparatus having a configuration.

  In addition, the present invention is not limited to the above-described multi-function peripheral, but is also applied to a printing apparatus (printer) having only a printing function, a copying machine (copying machine) having only a copying function, and a facsimile apparatus (fax) having only a facsimile function. Can be applied. Further, the printing function of the image forming apparatus of the present invention is not limited to the laser system, but may be an ink jet system, regardless of whether it is color printing or monochrome printing.

  The present invention can be changed as appropriate without departing from the spirit or concept of the invention which can be read from the claims and the entire specification, and an image forming apparatus accompanying such a change is also a technical idea of the present invention. include.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Case 3 Image forming part 4 Transfer part 5 Fixing part 8 Conveyance path 11 Control circuit unit (opening / closing judgment part)
DESCRIPTION OF SYMBOLS 15 Feed roller unit 16 Conveyance roller unit 17 Discharge roller unit 21 Ranging sensor 31 Opening part 32 Cover (lid body)
36 Open / close detection switch
41 Transport mechanism body 42 Separation unit

Claims (3)

A box-shaped housing having an opening;
A lid that closes the opening by contacting or approaching the housing and opens the opening by moving away from the housing;
A paper supply unit provided in the housing for supplying paper;
An image forming unit provided in the housing to form an image;
A transfer unit that is provided in the housing and transfers an image formed by the image forming unit to a sheet supplied by the sheet supply unit;
A fixing unit provided in the housing and fixing the image transferred by the transfer unit on a sheet;
A paper discharge unit that discharges the paper on which the image is fixed by the fixing unit provided in the housing;
A conveyance path through which the sheet moves from the sheet supply unit to the sheet discharge unit via the transfer unit and the fixing unit;
A transport mechanism for moving paper in the transport path;
A distance measuring sensor that is disposed at a position facing the conveyance path and detects a state of the sheet by measuring a distance between the sheet moving on the conveyance path;
The transport mechanism includes a transport mechanism main body and a separation unit that can be separated from the transport mechanism main body with the transport path as a boundary, and the separation unit transports the transport when the lid closes the opening. The transport path is formed between the mechanism body and the transport mechanism body so as to maintain a predetermined distance, and the lid body is separated from the housing when the lid body opens the opening. And an image forming apparatus that moves away from the transport mechanism main body.
An opening / closing determination unit that detects a distance between the transport mechanism main body and the separation unit by the distance measuring sensor and determines an opening / closing state of the opening by the lid based on the detection result; An image forming apparatus. Provided between the casing and the lid, and when the lid closes the opening, it is pushed by the lid or the casing to turn on, and the lid opens the opening. A switch that is turned off when separated from the lid or the housing when open,
The open / close determining unit detects that the distance between the transport mechanism main body and the separation unit is the predetermined distance by the distance measuring sensor, and the lid opens the switch when the switch is on. The image forming apparatus according to claim 1, wherein the opening is determined to be closed.   3. The image forming apparatus according to claim 1, wherein the distance measuring sensor detects a deflection amount of the sheet by measuring a distance from the sheet moving on the conveyance path. 4. .

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