JP4400221B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus in which a developing device is detachably mounted in an image forming apparatus such as a copying machine, a printer, or a facsimile machine.

As a method for detecting the remaining amount of developer (toner) in the developing unit, for example, as shown in Patent Document 1, a plurality of transmission type photosensors provided in a lower part of a storage chamber for storing toner in the developing unit It is described that the toner empty is determined based on the sum of the outputs.
Japanese Patent Laid-Open No. 6-110332

  The toner remaining amount detection method described above is basically performed to detect that the toner in the developing device has run out. That is, when the toner near the developing roller runs out, sufficient toner is not supplied to the developing roller, and the electrostatic latent image formed on the photosensitive drum is not sufficiently developed, which may cause image degradation. Because it becomes high. However, factors that cause image degradation include degradation of the toner itself, in addition to insufficient supply of toner. It has been found that the deterioration of the toner itself proceeds as it is agitated by the agitator in the developing device. It is hard to say that those described in the above-mentioned prior art documents sufficiently deal with this point.

  When increasing the amount of toner filled in the developing device, it is necessary to increase the capacity of the replenishing chamber for storing the toner in the developing device, but it is assumed that the overall size of the image forming apparatus is as compact as possible. The shape of the replenishing chamber must be expanded in the horizontal direction, not in the vertical direction. Therefore, the toner is stored so as to spread laterally from the developing roller, and the toner is stored at a position far from the developing roller. Since the toner is sequentially transferred by the agitator from the side closer to the developing roller, the toner is agitated for a long time and transferred to the developing roller for a longer distance, and the deterioration of the toner advances accordingly. Therefore, in the developing device in which the replenishing chamber is expanded in the lateral direction, the deterioration of the toner itself becomes large, and the deterioration toner is supplied to the developing roller only by detecting the absence of the toner in the vicinity of the developing roller. Despite the presence of toner, image deterioration will be caused.

  Accordingly, an object of the present invention is to provide a developing device capable of stably detecting the remaining amount of toner corresponding to toner deterioration in a developing device in which a plurality of supply chambers are arranged in parallel in the horizontal direction. It is.

An image forming apparatus according to the present invention includes a latent image carrier on which an electrostatic latent image is formed, a main body frame that pivotally supports the latent image carrier, and a developer carrier that supplies developer to the latent image carrier. A plurality of replenishing chambers arranged in parallel in the lateral direction of the body and the developer carrying body, and a developer that is detachably mounted in the main body frame, and detects the remaining amount of developer in the replenishing chamber A plurality of developer remaining amount detecting means arranged in the replenishing chamber farthest from the developer carrying member and the next replenishing chamber, and the amount of developer initially charged in the developing device with respect to the mounted developing device A type detecting unit for detecting a type based on the developer level, and a developer remaining amount detecting unit disposed in the furthest supply chamber in the case of a type having a large initial filling amount based on a detection signal from the type detecting unit. Select the detection signal to determine the remaining amount of developer Are both provided with a determining means selects and the remaining amount of the developer detection signal of said developer remaining amount detecting means disposed next farther the supply chamber in the case of the initial filling amount less type It is characterized by that.

  By having the configuration as described above, the developer remaining amount detecting means is arranged in different supply chambers with respect to the plurality of supply chambers arranged in parallel in the horizontal direction. The remaining amount can be detected stably by detecting the remaining amount of developer based on the detection signal of the developer remaining amount detecting means in the selected supply chamber. That is, in the case of a plurality of supply chambers arranged in parallel in the horizontal direction, the developer is sequentially transferred from the replenishment chamber to the replenishment chamber close to the developer carrier, and the developer disappears from the far replenishment chamber. If the remaining amount detection is performed in the replenishment chamber where the developer runs out as the developer remaining amount corresponding to the type of developer approaches, the remaining amount detection according to the type of developer is stabilized. And be able to do it.

  Furthermore, when the amount of developer initially filled differs according to the type of developer, if the amount of developer initially filled is large, the developer is stirred for a long time, so that the developer deteriorates and develops. It is necessary to detect the remaining amount in a state where the remaining amount of the agent is large. Conversely, when the amount of developer initially filled is small, the remaining amount may be detected in a state where the remaining amount of developer is small. Therefore, the developer remaining amount detecting means is arranged in the furthest replenishing chamber and the next furthest replenishing chamber, respectively, and when the initial filling amount is large, the detection signal of the developer remaining amount detecting means arranged in the farthest replenishing chamber If the remaining amount of developer is determined based on the detection signal of the developer remaining amount detecting means disposed in the next furthest supply chamber when the initial filling is small, The remaining amount can be detected more stably.

  Hereinafter, embodiments according to the present invention will be described in detail. The embodiments described below are preferable specific examples for carrying out the present invention, and thus various technical limitations are made. However, the present invention is particularly limited in the following description. Unless otherwise specified, the present invention is not limited to these forms.

  FIG. 1 is a schematic cross-sectional view of the entire image forming apparatus according to the present invention. A document reading unit 2 is arranged at the upper part of the image forming apparatus 1, and a paper feeding unit 3 and a recording unit 4 are arranged at the lower part from the bottom.

  In the document reading unit 2, the document placed on the document tray 11 provided on the document cover 10 is conveyed to the reading position by the document conveying device 12 and is discharged to the document discharge tray 13. At the reading position, a scanning device 16 equipped with a reading device 15 for optically reading a document is arranged so as to face the document. When reading a book or the like, the document cover 10 is rotated upward to place a read portion of the book or the like on the flat bed platen 14, and the scanning device 16 is moved as shown by an arrow to perform a reading operation. Is called. The above-described configuration is the same as that of a conventional document reading apparatus called a so-called ADF or flat bed type.

  In the paper feed unit 3, a paper feed cassette 17 is disposed, and a plurality of sheets of a predetermined size are stacked on the flapper 18. A pickup roller 19 is disposed at the right end of the paper feed cassette 17. The flapper 18 is urged upward by a spring member (not shown) so that the upper surface of the stacked paper comes into pressure contact with the pickup roller 19. When the pickup roller 19 is rotationally driven in this state, the sheets are fed one by one to the sheet conveyance path by the frictional force.

  The fed paper is first conveyed to the recording unit 4 by the feed roller 20 and the press roller 21. The recording unit 4 includes a developing unit 22, a paper dust removing roller 23, a corona charger 24, a photosensitive drum 25, a transfer roller 26, an exposure head 27, and a fixing roller 28 for recording on the conveyed paper. Yes. The paper dust removing roller 23 is composed of a conductive sponge or the like, and supplements toner or paper dust attached to the surface of the photosensitive drum 25 after transfer. The corona charger 24 uniformly charges the surface of the photosensitive drum 25 by the discharge from the corotron. An electrostatic latent image is formed by exposing the photosensitive drum 23 uniformly charged by the paper dust removing roller 23 and the corona charger 24 according to the image recording signal by the exposure head 25. Then, as will be described later, the toner in the developing device 22 is transferred to the electrostatic latent image formed on the photosensitive drum 25 to visualize the electrostatic latent image. The transfer roller 26 is installed at a position facing the photosensitive drum 25 with the paper interposed therebetween, and a toner image formed on the surface of the photosensitive drum 25 is transferred to the paper when a predetermined voltage is applied. The transferred toner image is sandwiched between the fixing roller 28 and the press roller 29 and heated and pressed to be fixed on the paper. The fixed paper is sandwiched between the paper discharge roller 30 and the press roller 31 and is carried out to the paper discharge tray 32.

  In FIG. 1, a sheet conveyance path is indicated by a one-dot chain line from the sheet feeding unit 3 to the sheet discharge tray 32. A conveyance roller and a paper guide arranged along the paper conveyance path constitute a paper conveyance unit.

  A reversal conveyance unit 40 is detachably mounted on a side surface of the apparatus main body, and a paper carry-out port 41 and a paper carry-in port 42 are formed on the mounting side surface. In the transport unit 40, two pairs of transport rollers, a feed roller 43 and a press roller 44, and a feed roller 45 and a press roller 46, are arranged up and down. Then, as shown by a two-dot chain line in FIG. 1, the reverse conveyance path branches off from the sheet conveyance path between the paper discharge roller 30 and the fixing roller 28, and the two pairs of conveyance rollers 43 and 44, 45 and 46 are separated. It is formed so as to pass through and to join the paper conveyance path between the roller pairs 20 and 21 and the pickup roller 19.

  When recording on both sides of the sheet, the sheet is conveyed to the sheet conveyance path indicated by the one-dot chain line in FIG. 1 and recorded on one side, and then the sheet is carried out to the sheet discharge tray 32 by the discharge roller 30. The carry-out operation is temporarily stopped in a state where the rear end portion of the paper is sandwiched between the paper discharge roller 30 and the press roller 31. Then, the paper discharge roller 30 is driven to rotate reversely, the paper is carried into the reverse conveyance path from the rear end, and is nipped by the feed roller 43 and the press roller 44 to be conveyed in the reverse conveyance path. Next, the paper is nipped by the feed roller 45 and the press roller 46 and further conveyed, and the paper is brought into contact between the roller pair 20 and 21. When the sheet is conveyed to the sheet conveyance path in this state, the other surface is recorded to face the photosensitive drum 25, and recording is performed on both sides of the sheet.

  FIG. 2 shows an enlarged cross-sectional view of the recording unit 3 in FIG. 3 shows an enlarged cross-sectional view of the developing device 22, and FIG. 4 shows a perspective view of the developing device 22 as viewed from above.

  As described above, the developing device 22, the paper dust removing roller 23, the corona charger 24, and the transfer roller 26 are disposed around the photosensitive drum 25, and between the corona charger 24 and the developer 22. Laser light is emitted from the exposure head 27 to the surface of the photosensitive drum 25 in accordance with the image recording signal.

  The developing device 22 is configured by sealing a lid 51 on the upper portion of the container body 50 by welding or fixing with screws. Three toner chambers 52, 53, and 54 are formed inside the container body 50 as toner replenishing chambers, and a supply chamber 57 having a developing roller 55 and a supply roller 56 at the side end on the photosensitive drum 25 side. Is formed. The first toner chamber 52 and the supply chamber 57 are partitioned by a partition plate 58 extending from the lower surface of the lid 51, and a supply opening 59 is formed in the partition plate 58.

  As shown in FIG. 3, the three toner chambers 52, 53, and 54 are configured to be arranged in parallel in the horizontal direction with the developing unit 22 mounted on the image forming apparatus 1. Paddles 60, 61, and 62 are provided as stirring transfer means in a substantially central portion of the chamber. In FIG. 2, assuming that the vertical direction of the paper surface is the front-rear direction of the developing device 22, the rotation shaft of each paddle is provided so that both ends in the front-rear direction are supported by the front-rear frame of the container body 50 and follow the front-rear direction. It has been. A blade 63 made of a flexible resin film is attached to the tip of the paddle 60 so as to follow the rotational direction. Similarly, a blade 64 is attached to the paddle 61, and a blade 65 is attached to the paddle 62. These blades 63 to 65 use a common member. The bottom surface of the container main body 50 is formed with sliding surface portions 66, 67, and 68 that are curved outward in a circular arc shape along the trajectory of the rotational movement of the blade attached to each paddle.

  The toner supplied to each of the toner chambers 52 to 54 is stored in the sliding surface portions 66, 67, and 68. When the paddles 60, 61, 62 rotate, the blades 63, 64, 65 rotate so as to slide on the sliding surface portions 66, 67, 68, respectively. The toner is picked up by the sliding motion of each blade, and the toner is agitated in each toner chamber to prevent deterioration due to toner aggregation. Further, as shown in FIG. 2, the blades 63, 64, 65 rotate counterclockwise, whereby the toner in the third toner chamber 54 is transferred to the second toner chamber 53, and the toner in the second toner chamber 53 Is transferred to the first toner chamber 52. The toner in the first toner chamber 52 is supplied to the supply chamber 57 from the supply opening 59 of the partition plate 58. At that time, the replenished toner is agitated by the paddle 60 in the first toner chamber 52 and preliminarily charged. The supply opening 59 has a slit shape in the front-rear direction, and the amount of toner supplied from the first toner chamber 52 to the supply chamber 57 can be adjusted by adjusting the opening width and the opening position. .

  The toner replenished in the supply chamber 57 is rubbed and charged by slidingly contacting the developing roller 55 while the supply roller 56 rotates, and is carried on the surface of the developing roller 55. On the developing roller 55, a developing blade 69 that regulates the layer thickness of the supplied toner is disposed close to the surface of the developing roller 55. As the developing roller 55 and the photosensitive drum 25 are in sliding contact with each other while rotating, a toner layer regulated to a constant layer thickness by the developing blade 69 adheres to the electrostatic latent image formed on the surface of the photosensitive drum 25. And developed.

  The developing device 22 is detachably attached to the image forming apparatus 1 in the front-rear direction. In FIG. 2, when the front side of the paper surface in the vertical direction is the front surface portion of the developing device 22 and the opposite side is the rear surface portion, the main body frame in the image forming device 1 is inserted when the developing device 22 is inserted into the image forming device 1. It is inserted into the mounting space formed in 70 from the rear surface and mounted. After being inserted, the developing device 22 is set in a state in which the container main body 50 is pushed up from below by a pressing mechanism 71 provided on the main body frame 70 of the image forming apparatus 1 and the developing roller 55 is in contact with the photosensitive drum 25. The Further, the toner remaining amount detecting sensor 72 is raised in conjunction with the pressing operation of the pressing mechanism 71 and is set in the concave groove 73 made of a transparent member provided on the sliding surface portion 67. Similarly, the toner remaining amount detection sensor 74 rises in conjunction with the mounting operation of the developing device 22 and is set in the concave groove 75 made of a transparent member provided on the sliding surface portion 68.

  In the pressing mechanism 71, a bottom surface of a pressing body 79 slidably disposed on a substrate 78 is in contact with a cam member 77 fixed to the rotating shaft 76. When the developing device 22 is mounted, the upper surface of the pressing body 79 faces the pressure contact portion 80 formed in a rib shape on the bottom surface of the developing device 22. When an operator rotates a lever (not shown) fixed to the end of the rotating shaft 76, the cam member 77 rotates clockwise to push up the pressing body 79 in the direction of the arrow. The developing roller 55 comes into contact with the photosensitive drum 25 by pressing. The other end portion of the swing lever 81 having the remaining toner amount detection sensor 72 fixed to one end portion is urged downward by a compression spring (not shown) so as to come into contact with the cam member 77. When the member 77 rotates clockwise, the swing lever 81 rotates clockwise around the shaft 82 and the toner remaining amount detection sensor 72 rises. Similarly, the toner remaining amount detection sensor 74 may be raised in conjunction with the pressing operation of the pressing mechanism 71.

  FIG. 7 shows an external view of the rear surface portion of the developing device 22. A rotation shaft 84 of the developing roller 55, a rotation shaft 85 of the supply roller 56, and a rotation shaft 86 of the paddles 60 to 62 are rotatably supported on the rear frame 83 of the container body 50. The end of each rotating shaft protrudes outward from the rear frame 83, and a drive transmission gear 87 is attached to the protruding portion. The driving shaft 88 is connected to the driving mechanism on the apparatus main body when the developing device 22 is mounted. Is transmitted to each rotary shaft by a transmission gear. A cover member 89 that covers a portion near the developing roller including the rotation shafts 84 and 85 is attached to the rear frame 83.

  FIG. 5 shows an enlarged view of the cover member 89 attached to the rear surface portion of the developing device 22. The cover member 89 is formed with a pair of mounting holes 90 for screwing to the rear frame 83, at locations corresponding to the rotating shaft 84 of the developing roller 55, the rotating shaft 85 of the supply roller, and the driving shaft 88. Are provided with circular openings 91, 92 and 93, respectively. On the back side of the cover member 89, there are a first contact member 94 that contacts the rotation shaft 84 of the developing roller 55, a second contact member 95 that contacts the rotation shaft 85 of the supply roller, and a blade that contacts the surface of the developing roller 55. A third contact member 97 that is in contact with the pressing plate 96 is attached.

  The first contact member 94 is made of a metal wire, and is bent in the center portion. One end is inserted and held in the holding opening 98 of the cover member 89. The other end is bent into a U-shape to form a contact portion 99, and is engaged and fixed to a narrow insertion hole 100 and a circular engagement hole 101 formed in the cover member 89. ing.

  Similarly to the first contact member 94, the second contact member 95 is made of a metal wire formed in a dogleg shape. One end is inserted and held in the holding opening 102, and the other end is bent. A U-shaped contact portion 103 is formed and engaged and fixed to the narrow insertion hole 104 and the circular engagement hole 105.

  The third contact member 97 is made of a metal thin wire, one end is formed in a coil spring shape and press-contacts the pressing plate 96, and the other end is bent at a right angle in an L shape to be a contact. A portion 106 is formed, and the tip is further bent into a hook shape.

  A terminal is disposed on the main body frame side corresponding to the contact portion of each contact member. When the developing device 22 is mounted, each terminal comes into contact with each contact portion and voltage is supplied from the apparatus main body side. It has become so.

  The cover member 89 is provided with a fourth contact member 107 and a fifth contact member 108 for identifying the developing device 22. The fourth contact member 107 is made of a thin metal wire, and one end thereof is bent in a hook shape and is inserted into the back surface side of a cover member 109 that is detachably provided on the cover member 89. The central portion is exposed on the front surface side of the cover member 89, and the other end is bent into a narrow insertion hole 110 provided in the cover member 89 and inserted on the back surface side of the cover member 89. . An insertion hole 111 similar to the insertion hole 110 is provided in the cover member 89, and when the length of the fourth contact member 107 is short, the other end is inserted into the insertion hole 111.

  The fifth contact member 108 is made of a thin metal wire, and, like the fourth contact member 107, one end is bent into a hook shape and inserted into the back side of the lid member 109. The other end is bent into a narrow insertion hole 102 provided in the cover member 89 and inserted into the back side of the cover member 89.

  The end portion inserted into the back surface side of the lid member 109 of the fourth contact member 107 and bent into a bowl shape is arranged to face the bent end portion of the fifth contact member 108, and any end portion is arranged. Also, a metal coil spring 113 is mounted. A fuse member 114 is held between the two coil springs 113.

  When the developing device 22 is attached to the apparatus main body, as shown in FIG. 6, the two connection terminals 115 a and 115 b on the apparatus main body side come into contact with the fourth contact member 107. The connection terminal 115a is disposed in contact with the insertion hole 111 and the connection terminal 115b is disposed in contact with the insertion hole 110. When the fourth contact member 107 has a length up to the insertion hole 110, both are provided. The connection terminal contacts the fourth contact member 107, but when the length is as short as the insertion hole 111, only the connection terminal 115 a contacts the fourth contact member 107. Further, the connection terminal 115 c on the apparatus body side is in contact with the fifth contact member 108 in the vicinity of the insertion hole 112.

  Accordingly, a state in which the developing device 22 is mounted and the connection terminal on the apparatus main body abuts is shown in a circuit diagram as shown in FIG. If the connection terminal 115a is set to the ground potential and the presence / absence of conduction between the connection terminals 115a and 115b is detected, the fourth contact member 107 is set long to the insertion hole 110 in the case of conduction detection. In the case of non-conduction detection, it is identified that the fourth contact member 107 is set to the insertion hole 111 short. Therefore, if the length of the fourth contact member 107 to be attached is changed according to the type of the developing device 22, the type of the developing device 22 can be easily identified.

  Further, if an electric current is applied between the connection terminals 115a and 115c to the extent that the fuse member 114 is melted, the fuse member 114 is cut when the developing device 22 is mounted. Therefore, the developing device attached to the apparatus main body is not electrically connected between the connection terminals 115a and 115c, and if the presence or absence of conduction between the connection terminals 115a and 115c is detected, the developing device 22 is new or used. Can also be identified.

  Next, the detection mechanism of the toner remaining amount detection sensors 72 and 74 will be described. As shown in FIG. 2, the remaining toner amount detection sensors 72 and 74 are set in concave grooves 73 and 75 provided on the bottom surface of the replenishing chamber of the developing device 22 when the developing device 22 is mounted. Become. Since the detection mechanisms of the remaining toner detection sensors 72 and 74 are the same mechanism, the case of the remaining toner detection sensor 72 will be described, and the description of the remaining toner detection sensor 74 will be omitted.

  FIG. 8 shows a cross-sectional view of the central portion of the concave groove 73 of FIG. 2 when cut in the vertical direction perpendicular to the paper surface. Two concave grooves 73 are provided on both sides of the remaining amount detection unit 116, and the concave groove 73 and the remaining amount detection unit 116 are integrally formed of a synthetic resin transparent member. As shown in FIG. 2, the remaining amount detection unit 116 is formed with a predetermined groove width along the rotation locus of the cleaning member 117 attached to the paddle 61, and the toner in the remaining amount detection unit 116 is Every time the cleaning member 117 slides in the remaining amount detection unit 116, the cleaning member 117 is once discharged out of the remaining amount detection unit 116. The cleaning member 117 is formed by stacking a plurality of rectangular sheet bodies made of rubber. The width of one sheet body is slightly larger than the groove width of the remaining amount detection unit 116 and is orthogonal to the traveling direction. It is attached to the surface to be Therefore, the both side portions 118 of the remaining amount detection unit 116 always slide with the sheet member of the cleaning member 117 in close contact, and the toner is once removed. On the other hand, in the toner remaining amount detection sensor 72, the light emitter 120 is fixed to the protruding portion 119 set in one concave groove 73, and the light receiving portion 120 receives light in the protruding portion 121 set in the other concave groove 73. The vessel 122 is fixed. The light receiver 122 outputs a detection signal depending on whether or not the light transmitted from the light emitter 121 through the remaining amount detector 116 is received.

  Each time the cleaning member 117 slides in the remaining amount detection unit 116 in synchronization with the rotation of the paddle 61, the light from the light emitter 120 passes through the remaining amount detection unit 116 and the light receiver 122 outputs a detection signal. When a sufficient amount of toner is stored in the replenishing chamber, the remaining amount detection unit 116 after sliding of the cleaning member 117 is filled with toner again, so that the light receiver 122 detects the light from the light emitter 120. However, when the remaining amount of toner in the replenishing chamber decreases, the amount of toner filling the remaining amount detection unit 116 decreases, and the light receiver 122 continues to detect light. Based on such a change in the detection signal, the toner remaining amount detection sensor 72 transmits a detection signal indicating the remaining amount of toner to the control unit of the apparatus main body.

  As a method for detecting the remaining amount of toner, a timing signal indicating the rotation of the paddle 61 can be added to the detection signal in which the light receiver 122 detects light. For example, the time from when the cleaning member 117 passes through the remaining amount detection unit 116 until the light receiver 122 stops detecting light is detected, and the correlation with the remaining amount of toner is determined in advance, and the correlation is obtained. The remaining amount of toner may be detected from the relationship. Further, the number of times the light of the light emitter 120 is blocked by the toner may be counted based on the presence or absence of a signal that detects the light of the light receiver 122, and may be used as an index indicating the degree of toner deterioration as the number of toner agitation.

  The toner remaining amount detection sensor 74 is disposed in the toner chamber 54 farthest from the supply chamber 57, and the toner remaining amount detection sensor 72 is disposed in the toner chamber 53 farthest from the next. Then, since the toner is sequentially transferred to the supply chamber by the paddle, the toner chamber 54 farthest from the supply chamber 57 first decreases the remaining amount of toner, and when the toner in the toner chamber 54 runs out, the next farthest toner chamber 53. The remaining amount of toner decreases. Therefore, if the toner remaining amount in the toner chamber where the toner runs out as it approaches the predetermined toner remaining amount according to the type of the developing device is detected, the remaining toner amount can be determined stably and accurately. Can do.

  FIG. 9 shows an example of a circuit configuration for notifying the replacement time of the developing device 22 in accordance with the type of the developing device 22. Detection signals from the remaining toner detection sensors 72 and 74 are input from the detection circuits 123 and 124 to the control circuit 125. The storage circuit 126 stores in advance data indicating the correlation between the toner presence / absence detection pattern from the toner remaining amount detection sensor and the toner remaining amount in the developing device 22, and the control circuit 125 correlates from the storage circuit 126. The remaining amount of toner in the developing unit 22 is monitored by reading the data and comparing the data with the input data from the detection circuit 123 or 124. On the other hand, from the detection circuit 127, detection signals regarding the presence / absence of the connection terminals 115a and 115b and the presence / absence of the connection terminals 115a and 115c are input to the control circuit 125.

  When detecting whether or not the connection terminals 115a and 115c are in a conductive state, the control circuit 125 detects whether or not the connection terminals 115a and 115c are in a conductive state. It is determined that there is, and the process proceeds to the subsequent processing. Then, current is supplied to such an extent that the fuse member 114 is blown, and the two terminals are made non-conductive. If both terminals are not conducting, the control circuit 125 determines that the product is a used product, and does not proceed to the subsequent processing. For example, the control circuit 125 performs control processing to display an error on the display circuit 128. Further, since there is a high possibility that a developing device suitable for the apparatus main body is not mounted, the apparatus may not be operated.

  Next, even in a new developing device, the amount of toner initially charged in the developing device is set larger in the developing device initially installed in the image forming apparatus and the developing device installed in the replenishing device. Yes. Therefore, using the fact that the presence / absence of the conductive state of the connection terminals 115a and 115b is determined by the length of the fourth contact member 107, when the fourth contact member 107 is long in advance (when conduction is present), the initial mounting is performed. If the developing device is short (when there is no continuity), it is preset that the developing device is a replenishment developer. When the developing device is mounted, the initial state is determined based on detection data regarding the presence / absence of continuity of the connection terminals 115a and 115b. It is determined whether it is a mounted developer or a replenishment developer.

  In the case of an initially mounted developing device, since the amount of toner to be initially filled is small, the amount of toner to be left corresponding to the toner deterioration is small. Therefore, the toner remaining amount detecting sensor 72 for detecting the remaining amount of the toner chamber 53 is detected. If the remaining amount is detected using this detection signal, stable and accurate determination can be made. Further, in the case of a replenishment developing device, since the amount of toner to be initially filled is large, the amount of toner to be left in response to toner deterioration increases, and a toner remaining amount detection sensor for detecting the remaining amount of the toner chamber 54 If the remaining amount is detected using 74 detection signals, a stable and accurate determination can be made.

  Accordingly, when the control circuit 125 receives the detection signal with continuity from the detection circuit 127, the control circuit 125 selects the detection signal from the detection circuit 123 and performs the remaining amount detection process thereafter to determine the remaining toner amount in the developing device 22. To do. When a detection signal indicating no continuity is received from the detection circuit 127, the detection signal from the detection circuit 124 is selected to determine the remaining amount of toner.

  By determining the remaining amount of toner in this way, it becomes possible to determine stably and accurately the amount of toner to be left according to the type of the developing device.

1 is a schematic sectional view of an entire image forming apparatus according to an embodiment of the present invention. It is an expanded sectional view regarding a recording part. It is an expanded sectional view regarding a developing device. It is an external view regarding the rear surface part of a developing device. It is an enlarged view regarding the electrical connection structure of a developing device. It is an enlarged view of the part which performs identification detection electrically. FIG. 10 is a circuit configuration diagram related to FIG. 9. 6 is an explanatory diagram regarding a detection operation of a toner remaining amount detection sensor. FIG. It is a circuit block diagram for performing electrical detection of a developing device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Document reading part 3 Paper feed part 4 Recording part
22 Developer
25 Photosensitive drum
50 Container body
51 lid
55 Developing roller
70 Body frame
71 Pressing mechanism
72 Toner level detection sensor
74 Toner level detection sensor

Claims (1)

A latent image carrier on which an electrostatic latent image is formed, a main body frame that pivotally supports the latent image carrier, a developer carrier that supplies developer to the latent image carrier, and a side of the developer carrier A plurality of replenishing chambers arranged in parallel in the direction and detachably mounted in the main body frame; and a replenishment farthest from the developer carrier while detecting the remaining amount of developer in the replenishing chamber A plurality of developer remaining amount detecting means arranged in a replenishing chamber next to the chamber, and a type detection for detecting a type based on the amount of developer initially filled in the developing unit with respect to the mounted developing unit And a detection signal of the developer remaining amount detection means disposed in the furthest replenishing chamber in the case of a type with a large initial filling amount based on a detection signal from the type detection means, Judging the remaining amount and low initial filling amount Image forming, characterized in that it comprises a determination means for determining the remaining amount of the selected and developer detection signal of the next furthest the replenishing chamber arranged the developer remaining amount detecting means in the case of apparatus.

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