JP2005128137A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus in which whether a drum unit is attached is detected without providing a drum unit detection sensor to it. <P>SOLUTION: The drum unit 110 having a photoreceptor drum 111 and a developing unit 120 having a developing sleeve 122 are attached to the main body 101 of the image forming apparatus so as to be detachable, respectively. The main body 101 of the image forming apparatus is provided with a remaining toner quantity detection sensor 130 which detects the amount of toner remaining in the toner storage container 121 of the developing unit 120. In the image forming apparatus 100, on the basis of the value of the detection, the remaining toner quantity detection sensor 130 detects whether the drum unit is attached to the main body 101 of the image forming apparatus. Consequently, this prevents the developing unit 120 and the main body 101 of the image forming apparatus from being damaged. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus including a developing unit and a drum unit.

  As a conventional image forming apparatus, there is an apparatus in which a drum unit having a photosensitive drum and a developing unit having a developing sleeve (mag roller) as an image forming unit are configured separately. In this type of image forming apparatus, a drum unit and a developing unit are detachably provided in the main body of the image forming apparatus. After the developing unit is inserted, the developing unit is pressed against the drum unit side with a predetermined biasing force by the biasing means.

  After the electrostatic latent image is formed on the surface of the photosensitive drum of the above-described drum unit, for example, jumping development is performed to blow toner on the drum surface to form a toner image composed of a thin toner layer. . In such development, the developing sleeve is arranged at a certain distance (hereinafter referred to as a developing gap) from the surface of the photosensitive drum. In the case where the drum unit and the developing unit are configured separately, means for holding the developing gap is required.

  FIG. 7 shows a structure for holding a developing gap between the surface of the photosensitive drum 1 rotatably supported on the drum unit side and the developing sleeve 2 rotatably supported on the developing unit side. ing. As shown in FIG. 7, the developing sleeve 2 is set so that the rotating shaft 3 thereof is parallel to the rotating shaft of the photosensitive drum 1. Further, at both ends of the developing sleeve 2, a gap forming roller 4 for defining a developing gap is provided coaxially with the developing sleeve 2. The radius of the gap forming roller 4 is set to be longer than the radius of the developing sleeve 2 by the developing gap. The clearance between the photosensitive drum 1 and the developing sleeve 2 can be kept constant by bringing the peripheral surface of the gap forming roller 4 into contact with the peripheral surface of the photosensitive drum 1.

  As described above, in the image forming apparatus in which the drum unit and the developing unit are configured separately, the developing unit is inserted after the drum unit is mounted on the main body of the image forming apparatus, and the end of the rotating shaft 3 of the developing sleeve 2 is inserted. A driven gear (not shown) provided on the image forming apparatus is set to mesh with a rotation transmission gear transmitted to a rotation driving source on the image forming apparatus main body side.

  However, in the above-described image forming apparatus, when the developing unit is mounted in a state where the drum unit is not mounted on the main body of the image forming apparatus, the gap forming roller 4 does not hit the photosensitive drum (drum base tube) 1 and is in the normal position. On the other hand, it is mounted at a shifted position. Accordingly, the rotation transmission gear rotates in a state where the rotation transmission gear of the image forming apparatus main body and the driven gear on the developing unit side are not engaged with each other. When the rotation transmission gear is rotated with the developing unit interfering with the developing unit, there is a possibility that the developing unit, the rotation transmitting gear, and the image forming apparatus main body side may be damaged.

  Conventionally, there is known a technique for detecting whether or not a developing unit is attached by detecting the remaining amount of a toner and a rotating state of a stirring rod in a toner chamber (see, for example, Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 4-188172 (first page, FIG. 4) JP 2002-40891 (second page, FIG. 1)

  However, in Patent Documents 1 and 2 described above, it is possible to detect whether or not the developing unit is mounted, but it is not possible to detect whether or not the drum unit is mounted. For this reason, the above-described problems when the developing unit is attached without the drum unit being attached to the main body of the image forming apparatus cannot be solved.

  Further, if a drum unit detection sensor for detecting whether or not the drum unit is mounted is provided on the image forming apparatus main body side, the cost of the image forming apparatus is increased.

  Accordingly, an object of the present invention is to provide an image forming device that can detect that a drum unit is not installed without newly providing a drum unit detection sensor, and can prevent damage to the developing unit and the image forming apparatus main body. To provide an apparatus.

  Another object of the present invention is to provide an image forming apparatus that can prevent damage to the developing unit, the image forming apparatus main body, and the gears of the rotational drive system at low cost, and to avoid the addition of a new sensor or the like. Therefore, the enlargement of the image forming apparatus is prevented.

  According to the first aspect of the present invention, a drum unit having a photosensitive drum and a developing unit having a developing sleeve are detachably attached to the image forming apparatus main body, and the remaining amount of toner in the toner container of the developing unit is detected. The present invention relates to an image forming apparatus in which a toner remaining amount detecting sensor is provided on the image forming apparatus main body side. The image forming apparatus according to the present invention is characterized in that the toner remaining amount detecting sensor also serves as a drum unit detecting means for detecting whether or not at least the drum unit is attached to the main body of the image forming apparatus.

  The invention according to claim 2 relates to the image forming apparatus according to claim 1. The image forming apparatus according to the present invention is characterized in that the toner remaining amount detecting sensor detects whether or not the developing unit is mounted.

  The invention described in claim 3 relates to the image forming apparatus described in claim 1 or claim 2. The image forming apparatus according to the present invention is characterized in that when the toner remaining amount detecting sensor detects that there is no remaining toner, the main body driving is stopped.

  According to a fourth aspect of the present invention, there is provided an image forming apparatus according to any one of the first to third aspects. The image forming apparatus according to the present invention includes an urging unit that urges the developing unit toward the drum unit, and the urging unit includes at least a pressing unit that contacts and presses the developing unit, and the pressing unit. And when the developing unit is positioned closer to the position where the drum unit is disposed than the normal position with respect to the image forming apparatus main body, the pressing portion is It is set so as to come into contact with the amount detection sensor, and the pressing portion is set so that a detection value detected by the toner remaining amount detection sensor is detected to a specific value.

  According to a fifth aspect of the present invention, a drum unit having a photosensitive drum and a developing unit having a developing sleeve are detachably provided in the image forming apparatus main body, and the remaining amount of toner in the toner container of the developing unit is detected. The present invention relates to a method for controlling an image forming apparatus including a control unit to which a remaining toner detection sensor is provided on the image forming apparatus main body side and a detection signal of the remaining toner detection sensor is input.

  According to the image forming apparatus control method of the present invention, the toner remaining amount detection sensor is set to detect a specific detection value when the developing unit is not disposed at a normal position, and the toner remaining amount detection is performed. When the detection value of the sensor is a specific value, the main body drive system is stopped, and when the detection value of the toner remaining amount detection sensor is not a specific value, it is used as a detection value of the remaining amount of toner. .

  According to the present invention, an image forming apparatus capable of detecting that a drum unit is not mounted without newly providing a drum unit detection sensor and preventing damage to the developing unit and the image forming apparatus main body side. realizable.

  Further, according to the present invention, it is possible to prevent the image quality from being deteriorated by preventing the development unit and the image forming apparatus main body from being damaged.

  Furthermore, according to the present invention, since addition of a new sensor or the like can be avoided, the apparatus can be prevented from being enlarged and the degree of freedom in designing the main body can be ensured.

  Hereinafter, an image forming apparatus according to the best mode for carrying out the present invention will be described. In this embodiment, a drum unit having a photosensitive drum and a developing unit having a developing sleeve are detachably provided in the main body of the image forming apparatus, respectively, and a toner remaining amount for detecting the remaining amount of toner in the toner container of the developing unit. A quantity detection sensor is provided on the image forming apparatus main body side. In the image forming apparatus, the remaining toner amount detecting sensor also serves as a drum unit detecting unit that detects whether or not at least the drum unit is mounted on the image forming apparatus main body. Naturally, the toner remaining amount detection sensor can detect whether or not the developing unit is attached. In addition, when the remaining toner detection sensor detects that there is no remaining toner, the main body drive is set to stop.

  In the present embodiment, the toner remaining amount detection sensor is set to detect a specific detection value when the developing unit is not disposed at the normal position, and the detection value of the toner remaining amount detection sensor is set to a specific value. It is preferable to perform control so that the main body drive system is stopped when the value is set. On the other hand, when the detection value of the toner remaining amount detection sensor is not a specific value, it is possible to perform normal toner remaining amount detection using the detected value of the toner remaining amount.

Hereinafter, details of an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. However, it should be noted that the drawings are schematic and the ratio of dimensions of each member is different from the actual one. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings is contained.
(Schematic configuration of image forming apparatus)
First, an outline of the image forming apparatus 100 will be described with reference to FIGS. 1 and 2. 1 is a perspective view of the main part of the image forming apparatus 100 according to the present embodiment, FIG. 2 is a cross-sectional view of the main part, FIG. 3 is a cross-sectional view of the main part in a normal wearing state, and FIG. FIG. 5 is a block diagram showing a control system, and FIG. 6 is a flowchart showing operations performed by the control unit.

  As illustrated in FIGS. 1 and 2, the image forming apparatus 100 according to the present exemplary embodiment includes a drum unit 110 and a developing unit 120 that are detachably attached to the image forming apparatus main body 101. The drum unit 110 includes a photosensitive drum 111 that is driven to rotate. The developing unit 120 includes a toner container 121 that stores toner containing a magnetic material, and a developing sleeve 122 that supplies toner to the electrostatic latent image formed on the photosensitive drum 111 for development. Yes.

  In particular, as shown in FIGS. 2 and 3, the image forming apparatus 100 includes a toner remaining amount detection sensor 130 that is in contact with the outer surface of the wall 121 </ b> A at the substantially bottom position of the toner container 121 and detects the remaining state of the toner. It is provided on the image forming apparatus main body 101 side. The toner remaining amount detection sensor 130 is connected to a control unit 160 provided on the image forming apparatus main body 101 side (see FIG. 5). The controller 160 controls the main body drive. Further, the image forming apparatus 100 includes an urging member 140 that urges the developing unit 120 toward the drum unit 110 in a state where the distance between the developing sleeve 122 and the photosensitive drum 111 is kept constant. It is provided on the main body side 101.

  On the drum unit 110 side, a rotation drive gear (not shown) that meshes with a rotation drive transmission gear (not shown) provided on the image forming apparatus main body 101 side is provided on the rotation shaft 111 </ b> A of the photosensitive drum 111. The developing unit 120 is supported by being pressed by the biasing member 140 toward the drum unit 110. In this embodiment, the drum unit 110 and the developing unit 120 are arranged in the horizontal direction, and the developing unit 120 is set to a slightly higher position.

  The image forming apparatus 100 according to the present exemplary embodiment includes an image forming unit 150 (see FIG. 2) that transfers a toner image onto a sheet-like recording material that is fed from a sheet feeding tray (not shown) and conveyed along a sheet conveyance path. And a fixing device (not shown) for fixing the toner image onto the recording material onto which the toner image has been transferred by the image forming unit 150, and a recording material on which the toner image is fixed via the fixing device onto a paper discharge tray (not shown). It is schematically configured with a discharge section for discharging.

The drum unit 110 includes the above-described photosensitive drum 111 at the lower portion facing the developing unit 120. Above the photosensitive drum 111 in the drum unit 110, a charger, a cleaner, a static eliminator, etc., not shown, are arranged. Further, for example, laser light can enter the photosensitive drum 111 from an exposure device (not shown).
(Development unit configuration)
As shown in FIG. 2, the developing unit 120 is provided with a developing sleeve 122 that faces the photosensitive drum 111 with a predetermined developing gap at the lower part on the side facing the photosensitive drum 111. In addition, a toner storage container 121 that stores toner is stored on the opposite side of the developing unit 120 from the side facing the photosensitive drum 111. As shown in FIGS. 2 and 3, the developing unit 120 in which the toner storage container 121 is stored has an opening 120 </ b> A that exposes the bottom of the toner storage container 121. When the developing unit 120 is normally inserted into the image forming apparatus main body 101, the toner remaining amount detection sensor 130 faces and contacts the outer surface of the bottom of the toner container 121 exposed from the opening 120A. It has become.

A toner supply means (not shown) such as a paddle is provided between the toner container 121 and the developing sleeve 122 to supply toner to the developing sleeve 122 side.
(Configuration of remaining toner detection sensor)
As shown in FIGS. 2 and 3, the toner remaining amount detection sensor 130 is provided in the step portion 102 formed in the image forming apparatus main body 101. In this embodiment, the toner remaining amount detection sensor 130 is formed with a protruding step 131 protruding in a cylindrical shape at the tip. As described above, when the developing unit 120 is inserted into the image forming apparatus main body 101, the toner remaining amount detection sensor 130 faces the outer surface of the bottom of the toner storage container 121 exposed from the opening 120A. To get.

In the image forming apparatus 100 of this embodiment, the toner remaining amount detection sensor 130 outputs the detection signal Ps to the control unit 160. Based on the detection signal Ps from the toner remaining amount detection sensor 130, the controller 160 determines whether or not the developing unit 120 is normally attached, that is, whether the drum unit 110 is attached and the developing unit 120 is attached. The control signal Cs is output so as to stop the main body drive when an abnormality is detected by determining whether or not the developing unit 120 is mounted.
(Configuration of biasing member)
The urging member 140 includes a pressing portion 141 and a coil spring 142 having one end fixed to the end portion of the pressing portion 141. The pressing part 141 is formed in a substantially cylindrical shape with, for example, resin. The other end of the coil spring 142 is connected to the image forming apparatus main body 101 side. The urging member 140 is provided with a guide member (not shown) so that the pressing portion 141 can slide with a predetermined stroke in a direction in which the pressing portion 141 advances and retreats toward the developing unit 120 side. Note that the urging member 140 is configured to include, for example, a urging force adding lever (not shown) in order to apply the urging force of the coil spring 142, and when the developing unit 120 is inserted into the image forming apparatus main body 101. The developing unit 120 may be urged toward the drum unit 110 by operating this lever. Further, the other end of the coil spring 142 may be simply fixed to the image forming apparatus main body 101 side without providing the biasing force adding lever as described above. Also in this case, it is preferable to provide a guide member that slides on the pressing portion 141.

In this embodiment, as shown in FIG. 3, an engagement recess 141 </ b> A that engages the end of the protruding step 131 of the toner remaining amount detection sensor 130 is formed in the lower intermediate portion of the pressing portion 141. Has been. The reason why the engagement concave portion 141A is formed in the pressing portion 141 in this way is that the toner remaining in the engagement concave portion 141A when the development unit 120 is inserted from the normal position to the drum unit 110 side with the development unit 120 inserted. This is because the end of the protruding step 131 of the detection sensor 130 is engaged so that the detection value of the remaining toner detection sensor 130 outputs a specific value. This specific detection value means that the toner remaining amount detection sensor 130 is not located at the bottom of the toner container 121 but the development unit 120 is located closer to the drum unit 110 than the normal position, or the development unit 120 is inserted. This is so that the remaining toner amount detection sensor 130 can recognize that there is no toner. Specifically, the resin material constituting the pressing portion 141 is set so that the value indicating magnetism becomes zero, or the magnetic material is set so as to be larger than the value indicating magnetism at the maximum value of the remaining amount of toner. What is necessary is just to comprise so that it can distinguish from the value which performed the setting of embedding etc. and detected the toner storage container 121 as object.
(Control method of image forming apparatus)
Here, the control method, operation, and operation of the image forming apparatus 100 of the present embodiment will be described.

  First, when the developing unit 120 is inserted after the drum unit 110 is mounted on the image forming apparatus main body 101, the developing sleeve 122 of the developing unit 120 contacts the photosensitive drum 111 of the drum unit 110 via a predetermined developing gap. (See FIG. 7). By operating the biasing member 140 side, the developing unit 120 can be biased toward the drum unit 110 side with a predetermined pressing force. At this time, as shown in FIG. 3, the bottom outer surface of the toner container 121 of the developing unit 120 is exposed from the opening 120 </ b> A formed in the developing unit 120 and comes into contact with the toner remaining amount detection sensor 130. The remaining amount can be detected. As shown in FIG. 5, the detection value detected by the remaining toner detection sensor 130 is output to the control unit 160 as a detection signal Ps. At this time, as shown in the flowchart of FIG. 6, the control unit 160 determines whether or not the detection value of the toner remaining amount detection sensor 130 is a specific value (step S1). If the toner remaining amount detection sensor 130 is not a specific detection value (No), it is assumed that the developing unit 120 is normally attached, and the remaining toner amount is determined from the detected value (step S2). . Note that, as described above, the urging member 140 may be configured not to include the urging force adding lever or the like, and to automatically apply a pressing force when the developing unit 120 is inserted.

  As described above, when the developing unit 120 is normally mounted after the drum unit 110 is mounted, the rotated driving gear (not shown) provided on the rotation shaft of the developing sleeve 122 of the developing unit 120 serves as the image forming apparatus. It will be in the state which meshes | engages appropriately with the rotational drive transmission gear provided in the main body 101 side. In this state, the detection value of the toner remaining amount detection sensor 130 is a state in which the main body can be driven in order to detect a value indicating a normal range of magnetism.

  On the other hand, when the developing unit 120 is inserted when the drum unit 110 is not mounted in the image forming apparatus main body 101, the developing sleeve 122 of the developing unit 120 cannot contact the photosensitive drum, and the developing unit 120. Is located deeper in the image forming apparatus main body 101 than the normal position. Incidentally, if the developing unit 120 is inserted into the image forming apparatus main body 101 and a stopper is provided so that the developing sleeve 122 is disposed at a predetermined regular position without contacting the photosensitive drum 111, It becomes impossible to generate a predetermined contact pressure by pressing with the urging member 140.

  In such a situation, the bottom outer surface of the toner container 121 exposed from the opening 120 </ b> A of the developing unit 120 is located closer to the arrangement position of the drum unit 110 than the remaining toner amount detection sensor 130. At this time, the pressing portion 141 moves to the developing unit 120 side by the biasing force of the coil spring 142 as compared with the case where the developing unit 120 is in the normal position. For this reason, the engagement concave portion 141 </ b> A formed in the lower surface intermediate portion of the pressing portion 141 is engaged with the end portion of the protruding step portion 131 of the toner remaining amount detection sensor 130. The pressing portion 141 is set in advance so that the engaging recess 141A is engaged with the protruding step portion 131 when the pressing portion 141 moves to the developing unit 120 side as much as possible. Thus, when the protruding step 131 of the toner remaining amount detection sensor 130 is engaged with the engagement recess 141A of the pressing portion 141, the value indicating the magnetism detected by the toner remaining amount detection sensor 130 is a specific value, for example, zero. Alternatively, an excessive value is detected and the detection signal Ps is output to the control unit 160. Then, as shown in FIG. 6, it is determined whether it is a specific detection value (step S1). Then, the control unit 160 determines that the detected value is a specific value based on the detection signal Ps, and the developing unit 120 is not mounted or the developing unit 120 is arranged with a deviation from the normal position. Therefore, the control signal Cs for stopping the driving system M of the main body is output to stop the driving system M (step S3).

  As a result, even if the developing unit 120 is mounted without the drum unit 110 being mounted, the drive system is stopped, so the driven gear provided on the developing sleeve 122, the main body of the developing unit 120, It is possible to prevent problems such as damage to the rotational drive system on the image forming apparatus main body 101 side.

Further, according to the present exemplary embodiment, it is not necessary to newly provide a sensor for detecting the drum unit 110, and it is possible to detect whether the drum unit 110 or the developing unit 120 is not attached from the detection value of the toner remaining amount detection sensor 130. For this reason, according to the present embodiment, since the number of parts is not increased, the cost can be reduced without increasing the size of the image forming apparatus 100.
(Other examples)
It should not be understood that the above description and drawings, which form part of the disclosure of the embodiments of the present invention, limit the present invention. From this disclosure, various alternative embodiments, examples, and operational techniques will be apparent to those skilled in the art.

  For example, in the above-described embodiment, the toner storage container 121 is stored in the developing unit 120. However, the toner storage unit may be integrally formed in the developing unit 120 as a matter of course.

  Further, the urging member 140 may be configured to include other urging elements without using the coil spring 142.

  The present invention can be used in the field of manufacturing an image forming apparatus such as a copying machine, a facsimile machine, a printer, or a multifunction machine having both functions.

1 is a perspective view illustrating a main part of an image forming apparatus according to an embodiment of the present invention. 1 is a cross-sectional view of a main part showing an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of a main part showing a state in which the developing unit is normally mounted in the image forming apparatus according to the embodiment of the present invention. FIG. 3 is a cross-sectional view of a main part showing a state where the developing unit is abnormally mounted in the image forming apparatus according to the embodiment of the present invention. FIG. 3 is a diagram illustrating a control system in the image forming apparatus according to the embodiment of the present invention. It is a flowchart which concerns on the Example of this invention. FIG. 3 is a perspective view showing a photosensitive drum and a developing sleeve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Image forming apparatus, 101 ... Image forming apparatus main body, 110 ... Drum unit, 111 ... Photosensitive drum, 120 ... Developing unit, 121 ... Toner storage container, 122 ... Developing sleeve, 130 ... Toner Remaining amount detection sensor 140... Biasing member 141... Pressing portion 142.

Claims (5)

A drum unit having a photosensitive drum and a developing unit having a developing sleeve are detachably provided in the main body of the image forming apparatus, respectively, and a toner remaining amount detection sensor for detecting the remaining amount of toner in the toner container of the developing unit An image forming apparatus provided on the image forming apparatus main body side,
The toner remaining amount detection sensor also serves as a drum unit detection unit that detects whether or not at least the drum unit is mounted on the main body of the image forming apparatus.   The image forming apparatus according to claim 1, wherein the toner remaining amount detection sensor detects whether or not the developing unit is attached.   3. The image forming apparatus according to claim 1, wherein when the toner remaining amount detection sensor detects that there is no toner remaining, the main body driving is stopped. Urging means for urging the developing unit toward the drum unit;
The biasing means comprises at least a pressing portion that contacts and presses against the developing unit, and a spring portion biased in a direction of pushing out the pressing portion,
When the developing unit is positioned closer to a position where the drum unit is disposed than a normal position with respect to the image forming apparatus main body, the pressing portion is set to contact the toner remaining amount detection sensor;
4. The image according to claim 1, wherein the pressing portion is set such that a detection value detected by the toner remaining amount detection sensor is detected to a specific value. 5. Forming equipment. A drum unit having a photosensitive drum and a developing unit having a developing sleeve are detachably provided in the main body of the image forming apparatus, respectively, and a toner remaining amount detection sensor for detecting the remaining amount of toner in the toner container of the developing unit A control method of an image forming apparatus provided with a control unit that is provided on the image forming apparatus main body side and receives a detection signal of the toner remaining amount detection sensor,
When the developing unit is not disposed at a normal position, the toner remaining amount detection sensor is set to detect a specific detection value,
When the detection value of the toner remaining amount detection sensor is a specific value, the main body drive system is stopped,
A control method for an image forming apparatus, wherein a detection value of a remaining amount of toner is used when a detection value of the remaining toner detection sensor is not a specific value.

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