JP2009151027A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent recording medium or medium detection member from being damaged even when removing jammed recording medium which has been made into bellows in an image forming apparatus for forming the image to the recording medium by transporting the recording medium. <P>SOLUTION: The image forming apparatus includes: a sliding member 18c which can retract an ejection sensor 18 which is abutted to the recording medium and revolved for detecting the recording medium from a medium transporting path; a supporting member 18d for restricting the sliding direction; and a spring 18e for biasing the sliding member 18c in a direction separating from a revolving fulcrum 18a. When jamming of the recording medium occurs, the sliding member 18c is retracted from the medium transporting path. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a configuration of an image forming apparatus that conveys a recording medium and forms an image on the recording medium.

  Generally, when clearing a jam in an image forming apparatus, it is necessary for an operator to open the cover and remove the jammed recording medium. In this case, the recording medium is a recording medium provided in the medium conveyance path. There is a case where the medium detection member for traveling detection is caught and the medium detection member is damaged or the recording medium is broken.

In order to prevent the medium detection member from being damaged and to prevent the medium from being torn, the medium detection member is rotated and retracted from the medium conveyance path when the cover is opened and the recording medium causing the jam is removed. A technique is disclosed (for example, see Patent Document 1).
Japanese Patent Laying-Open No. 2005-60058

  However, in the above-described method of retracting the medium detection member, when a jam occurs in which the recording medium is folded in an accordion shape, the medium detection member is stuck and caught in the recording medium, and the medium detection member is rotated. When the recording medium is used, there is a problem that the recording medium is further broken or the medium detecting member is damaged.

  The present invention employs the following means in order to solve the aforementioned problems. That is, in an image forming apparatus that conveys a recording medium and forms an image on the recording medium, the image forming apparatus includes an opening for taking out the recording medium from a medium conveyance path, and a detection unit that detects the recording medium. A medium detecting member that rotates in contact with the recording medium, the medium detecting member including a sliding member, a support member that regulates a sliding direction, and a direction in which the sliding member is separated from the rotation fulcrum. And an urging member that urges the sliding member so that the sliding member can be retracted from the medium conveyance path when a jam of the recording medium occurs.

  According to the image forming apparatus of the present invention, the image forming apparatus includes an opening for taking out the recording medium from the medium conveyance path, and a detection unit for detecting the recording medium, and the detection unit rotates in contact with the recording medium. A medium detection member, the medium detection member includes a sliding member, a support member that regulates the sliding direction, and a biasing member that biases the sliding member in a direction away from the rotation fulcrum; Since the sliding member can be retracted from the medium conveyance path when a jam occurs in the recording medium, the ejection sensor is not caught by the recording medium when the jam is removed, and the ejection sensor is damaged or the medium is broken. Can be prevented.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element common to drawing.

(Constitution)
FIG. 1 is a side sectional view illustrating the configuration of the image forming apparatus according to the first exemplary embodiment. Reference numeral 1 denotes an image forming apparatus, which includes a medium cassette 2 in which a recording medium 19 is set.

  Reference numeral 3 denotes a paper feed roller, which feeds the recording medium 19 separated one by one by the separation piece 4. Reference numeral 5 denotes a paper feed sensor as a medium detection member, which detects the transported recording medium 19.

  Reference numeral 6 denotes a registration roller that conveys the recording medium 19 pressed by the pressure roller 7 to the medium conveying path 8 in order to eliminate the curling of the recording medium 19.

  Reference numeral 9 denotes a passage sensor as a medium detection member, which detects the recording medium 19 that has passed. Reference numeral 10 denotes a detachable image forming unit, which includes a photosensitive drum 12, a charging roller 13, and a developing roller 15, and forms a toner image.

  Here, the formation of a toner image in the image forming unit 10 will be described. When the surface of the rotating photosensitive drum 12 reaches the position of the charging roller 13, the surface of the photosensitive drum 12 is negatively charged by the charging roller 13.

  When the surface portion of the negatively charged photosensitive drum 12 comes under the exposure head 14, the exposure head 14 is exposed to form an electrostatic latent image based on image data in the charged portion. This electrostatic latent image is developed by the developing roller 15 and becomes a toner image. Then, the toner image is transferred to the recording medium 19 conveyed by the transfer roller 11.

  Reference numeral 16 denotes a heat roller that performs high-temperature and high-pressure processing of the toner image transferred to the recording medium 19. Reference numeral 17 denotes a backup roller, which performs a fixing process on the toner image that has been pressed at a high temperature.

  Reference numeral 18 denotes a discharge sensor as a medium detection member that is a detection unit that detects a recording medium, and is installed in a rotatable state on a frame portion inside the image forming apparatus 1. The contact of the recording medium 19 that is conveyed after being subjected to the high-temperature and high-pressure fixing process is detected.

  Here, the configuration of the discharge sensor 18 will be described in detail with reference to the configuration diagrams showing the details of the discharge sensor of FIGS. The discharge sensor 18 can be rotated about a rotation fulcrum 18a, and includes a sliding member 18c, a support member 18d, and a spring 18e.

  The sliding member 18c has a structure that can be housed inside the support member 18d, and the support member 18d regulates the sliding direction of the sliding member 18c in the direction of arrows AB shown in FIG. A spring 18e as an urging member is installed between the sliding member 18c and the support member 18d. The spring 18e attaches the sliding member 18c in a direction away from the rotation fulcrum 18a, that is, in the arrow A direction. To force.

  The sliding member 18c has a protruding portion 18f, and the supporting member 18d is fitted with the protruding portion 18f, and is provided with a long hole 18g that can move in the arrow AB direction. By pushing down the protrusion 18f in the direction toward the rotation fulcrum 18a, that is, in the direction of the arrow B, the sliding member 18c can be accommodated in the support member 18d as shown in FIG.

  Further, a light shielding part 18b is provided at the tip of the support member 18d, and a photo interrupter 20 described later detects the movement of the light shielding part 18b.

  When the recording medium 19 has not reached the discharge sensor 18, the discharge sensor 18 is a sliding member 18c that is a contact portion with the recording medium 19 as shown in the configuration diagram of the main part of the image forming apparatus in FIG. However, it is in a state of protruding to the medium conveyance path 8 that conveys the recording medium 19 that has been subjected to the high-temperature and high-pressure fixing process.

  On the other hand, when the recording medium 19 comes into contact with the sliding member 18c, the discharge sensor 18 rotates in the direction of arrow E about the rotation fulcrum 18a as shown in the configuration diagram of the main part of the image forming apparatus in FIG.

  The rotation of the discharge sensor 18 is grasped when the photo interrupter 20 detects the movement of the light shielding portion 18 b of the discharge sensor 18. When the recording medium 19 finishes passing through the discharge sensor 18, the discharge sensor 18 rotates about the rotation fulcrum 18a by its own weight and returns to the state shown in FIG.

  Reference numeral 21 denotes a medium guide whose tip has a rib shape 21a. Then, the recording medium 19 detected by the discharge sensor 18 is conveyed along the shape of the medium guide 21.

  The medium guide 21 is an opening as a cover member that also serves as an exterior cover, and can be opened and closed. The medium guide 21 is opened in the direction of arrow D when a jam occurs or when maintenance is performed.

  A discharge roller 22 discharges the recording medium 19 together with the subordinate roller 23 to the stacker cover 24.

  A lever 25 is a link member with the discharge sensor 18. The lever 25 has an arm shape 25 a on the medium guide 21 side, and is arranged so that the arm shape 25 a is pushed and moved by the rib shape 21 a which is a part of the medium guide 21 when the medium guide 21 is opened and closed.

  When the arm shape 25a is pushed and moved, the lever 25 rotates in the arrow C direction around the lever fulcrum 25b.

  The arc shape 25c is an arc shape centering on a rotation fulcrum 18a with the discharge sensor 18, and does not hinder the rotation of the discharge sensor 18 performed at the time of medium detection.

  The arc shape 25c is in contact with the protrusion 18f of the discharge sensor 18, and the protrusion 18f moves in the direction of arrows AB shown in FIG.

  Here, a method for detecting a jam in the recording medium 19 will be described with reference to the main configuration diagram of the image forming apparatus in FIGS. 4 and 5.

  As shown in FIG. 5, when the recording medium 19 conveyed by the heat roller 16 and the backup roller 17 comes into contact with the discharge sensor 18, the discharge sensor 18 is pushed down by the recording medium 19, and the arrow is centered on the rotation fulcrum 18a. Rotate in E direction.

  By the rotation of the discharge sensor 18, the light shielding portion 18 b of the discharge sensor 18 is separated from the photo interrupter 20. Therefore, the light from the light emitting portion (not shown) is detected by the light receiving portion (not shown) of the photo interrupter 20. By doing so, it is detected that the recording medium 19 is passing.

  When the jam of the recording medium 19 does not occur, the discharge sensor 18 is kept pushed by the recording medium 19 until the recording medium 19 finishes passing over the discharge sensor 18.

  When the recording medium 19 finishes passing over the discharge sensor 18, the discharge sensor 18 rotates about the rotation fulcrum 18a by its own weight and returns to the state shown in FIG.

(Operation)
With the above configuration, the image forming apparatus according to the first exemplary embodiment operates as follows. This operation will be described in detail below with reference to the jam detection operation explanatory diagram of FIG. 6 and the operation explanatory diagrams of FIG. 7 and FIG.

(Jam detection operation)
First, an operation for detecting the occurrence of a jam and the type of jam will be described with reference to FIG.

  As shown in the figure, the time when the discharge sensor 18 is pushed down at the timing T0 and the light shielding portion 18b moves away from the photo interrupter 20, that is, the passage time of the recording medium 19, the recording medium 19 normally moves over the discharge sensor 18. In the case of passing, as shown in FIG. 5A, when the length of the recording medium 19 is L1, it is obtained by L1 / conveying speed V, and when this time is t1, normal jam occurs and conveyance is performed. When the recording medium 19 is stopped or stagnated, the state in which the ejection sensor 18 is pushed down by the recording medium 19 becomes longer. Therefore, although not shown, the recording medium 19 when the recording medium 19 is jammed passes over the ejection sensor 18. Such time, for example, t2 is longer than the normal transit time t1.

  On the other hand, as shown in FIG. 5B, when a jam occurs in which the recording medium 19 is folded in a bellows shape, the recording medium 19 is folded in a bellows shape, and the medium length is equal to or less than L1. Since L3, the recording medium 19 finishes passing over the discharge sensor 18 in a time shorter than the normal time t1, and the discharge sensor 18 rotates about the rotation fulcrum 18a by its own weight, so that the state shown in FIG. And return.

  Therefore, the time t3 required for the recording medium 19 to pass over the discharge sensor 18 when a jam occurs in which the recording medium 19 is folded in a bellows shape, the recording medium 19 normally passes over the discharge sensor 18. It becomes shorter than the time t1.

  From the above, the occurrence and type of jam can be detected by comparing the time t1 required for the recording medium 19 to pass over the discharge sensor 18 and the passage time of the recording medium 19 when no jam occurs. Can do. The reference passage time t1 may be stored in advance in a control unit (not shown) for each size of the recording medium 19.

  Then, whether or not a normal jam has occurred or a jam folded in a bellows shape is displayed on a display panel (not shown) of the image forming apparatus 1 to notify the operator.

(Jam removal operation)
Next, the jam removal operation when a jam is detected as described above will be described with reference to the operation explanatory diagrams of FIGS. First, as shown in FIG. 7, when a jam occurs in which the recording medium 19 is folded in a bellows shape, when the medium guide 21 is opened in the direction of the arrow D, as shown in FIG. The rib shape 21a pushes up the arm shape 25a which is a part of the lever 25. By pushing up the arm shape 25a, the lever 25 rotates in the direction of arrow C shown in FIG. 8 about the lever fulcrum 25b.

 At this time, as shown in FIG. 8, the projection 18f of the sliding member 18c is pushed down in the direction of the arrow B in the hole 18d of the discharge sensor 18 by the arc shape 25c of the lever 25.

  As a result, the sliding member 18c is housed inside the support member 18d, and the portion of the discharge sensor 18 that protrudes to the medium conveyance path 8 is retracted.

  When the operator removes the bellows-shaped recording medium 19 that is the cause of the jam and then closes the medium guide 21, the sliding member 18c is attached in the direction of arrow A described with reference to FIG. 2 by the spring 18e. And protrudes into the medium conveyance path 8.

  At this time, the arc shape 25c is pushed up by the protrusion 18f, and the lever 25 rotates around the lever fulcrum 25b and returns to the state shown in FIG.

(Effect of Example 1)
As described above, according to the image forming apparatus of the first embodiment, when the medium guide is opened in order to release the jam, the sliding member of the discharge sensor that protrudes to the medium conveyance path is stored in the support member. However, even if a jam occurs in which the recording medium is folded in a bellows shape, the discharge sensor is not caught by the recording medium when the jam is removed, and the discharge sensor is damaged. And media tearing can be prevented.

(Constitution)
The image forming apparatus according to the second embodiment has a configuration in which a sliding arc-shaped member 26 and a solenoid 27 are provided as shown in FIGS. 9 and 10.

  The sliding arc-shaped member 26 is a link member with the discharge sensor 18 and has an arc shape that is slidable in the direction of arrow FG with the rotation fulcrum 18a of the discharge sensor 18 as the center. Further, the shape does not hinder the rotation of the discharge sensor 18 performed at the time of medium detection.

  When the solenoid 27 detects a jam of the recording medium 19, the control unit (not shown) drives the sliding arc-shaped member 26 in the direction of arrow G, and the projection 18f is pushed down in the hole 18g in the direction of arrow B. The sliding member 18c is housed inside the support member 18d, and the portion of the sliding member 18c protruding into the medium transport path 8 is retracted. Since other configurations are the same as those of the image forming apparatus of the first embodiment, detailed description thereof is omitted for the sake of brevity.

(Operation)
With the above configuration, the image forming apparatus according to the second exemplary embodiment operates as follows. This operation will be described in detail below with reference to the operation explanatory diagrams of the image forming apparatus in FIGS. Note that the jam detection operation is the same as that of the first embodiment, and therefore detailed description thereof is omitted for the sake of brevity.

  In the state shown in FIG. 10, when the jam of the recording medium 19 occurs and the jam of the recording medium 19 is detected, the solenoid 27 slides by driving a control unit (not shown), and the sliding arc member 26 is moved to the arrow. Suction in the G direction. At this time, the projection 18f of the sliding member 18c constituting the discharge sensor 18 is pushed down in the direction of the arrow B by the sliding arc-shaped member 26 in the hole 18g.

  As a result, as shown in FIG. 11, the recording member 19 in which jamming occurs exists in the portion where the sliding member 18c is housed inside the support member 18d and protrudes to the medium conveyance path 8 of the discharge sensor 18. Is retracted from the medium conveyance path 8 to be performed.

  When the operator opens the medium guide 21 and removes the recording medium 19 that caused the jam, and the jam is released, the solenoid 27 stops the suction and slides in the direction of arrow F. The member 18c is urged in the direction of arrow A by the spring 18e, and again protrudes into the medium transport path 8 as shown in FIG.

(Effect of Example 2)
As described above, according to the image forming apparatus of the second embodiment, when the jam of the recording medium is detected, the slide member of the discharge sensor is housed inside the support member and retracted from the medium conveyance path. Thus, the sliding member can be retracted more reliably from the medium conveyance path, and the discharge sensor is not caught by the recording medium when the jam is removed, so that the breakage of the discharge sensor and the tearing of the medium can be further reliably prevented.

<< Other modifications >>
In the above description of the embodiment, the discharge sensor 18 which is one of the medium detection members has been described as an example. However, the present invention can be easily applied to the paper feed sensor 5, the passage sensor 9 and the like.

  In the above description of the embodiment, the printer has been described as an example. However, the present invention can be easily applied to an image forming apparatus such as a FAX or a copier.

  The present invention can be widely used in an image forming apparatus such as a printer using a recording medium.

1 is a side sectional view of an image forming apparatus according to Embodiment 1. FIG. It is a block diagram which shows the detail of the discharge | emission sensor of Example 1. FIG. It is a block diagram which shows the detail of the discharge | emission sensor of Example 1. FIG. 1 is a main part configuration diagram of an image forming apparatus of Embodiment 1. FIG. 1 is a main part configuration diagram of an image forming apparatus of Embodiment 1. FIG. 6 is a diagram illustrating a jam detection operation of the image forming apparatus according to the first exemplary embodiment. FIG. FIG. 6 is an operation explanatory diagram of the image forming apparatus according to the first exemplary embodiment. FIG. 6 is an operation explanatory diagram of the image forming apparatus according to the first exemplary embodiment. FIG. 3 is a main part configuration diagram of an image forming apparatus according to a second embodiment. FIG. 6 is an operation explanatory diagram of the image forming apparatus of Embodiment 2. FIG. 6 is an operation explanatory diagram of the image forming apparatus of Embodiment 2.

Explanation of symbols

1: Image forming apparatus 8: Medium transport path 18: Discharge sensor 18a: Rotating fulcrum 18c: Sliding member 18d: Support member 18e: Spring 19: Recording medium 20: Photo interrupter 21: Medium guide 25: Lever 25a: Arm shape 25b: Lever fulcrum 25c: Arc shape

Claims (3)

An image forming apparatus that conveys a recording medium and forms an image on the recording medium,
An opening for taking out the recording medium from the medium conveying path;
A detection unit for detecting the recording medium,
The detection unit includes a medium detection member that rotates in contact with the recording medium,
The medium detection member includes a sliding member, a support member that regulates the sliding direction, and a biasing member that biases the sliding member in a direction away from the rotation fulcrum, and the recording medium is jammed. An image forming apparatus, wherein the sliding member can be retracted from the medium conveyance path. The opening includes a cover member that opens and closes the opening, and includes a mechanism that links the cover member and the sliding member;
The link mechanism moves the sliding member in the direction of the rotation fulcrum with the opening operation of the cover member, and separates the sliding member from the direction of the rotation fulcrum with the closing operation of the cover member. The image forming apparatus according to claim 1.   When the jam of the recording medium is detected, the link mechanism slides a solenoid provided on the link member to move the sliding member in the direction of the rotation fulcrum, and when the jam of the recording medium is released The image forming apparatus according to claim 1, wherein the sliding of the solenoid is stopped and the sliding member is separated from the rotation fulcrum.

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