JP5488312B2 - Image forming apparatus - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine having a combination of these functions. It relates to the device.

  In an electrophotographic image forming apparatus, in order to stably supply toner to a developing device, a method of supplying toner from a toner container to a sub hopper and further supplying toner from the sub hopper to the developing device is widely adopted. ing. In the image forming apparatus of this type, the toner supply from the toner container to the sub hopper and the toner supply from the sub hopper to the developing device have been performed by different drive sources. From the standpoint of achieving this, a toner that supplies these toners with a common drive source has been developed and is commercially available.

  On the other hand, the toner used in the electrophotographic image forming apparatus is a consumable item, and the toner is sequentially replenished to the developing device by replacing the toner container. When the toner container is replaced with a new one, the toner counter is reset to zero and a message to that effect is displayed to the user. When the remaining amount of toner is low, a message to that effect is displayed.

  Conventionally, whether or not a toner container has been replaced with a new one has been determined by an IC chip or a fuse attached to the toner container. For example, in Patent Document 1, a non-volatile memory is attached to a process cartridge containing toner, and the apparatus body reads the memory to determine whether it is new.

  However, providing an electronic component such as an IC chip in a toner container or process cartridge as a replacement member requires electrical wiring and the like, which complicates the structure and may increase the size of the apparatus. . Further, when the toner container is discarded, it is necessary to separate an electronic component such as an IC chip from the container body.

JP-A-2009-128682

  Therefore, an object of the present invention is to replace a toner container with a new one in an image forming apparatus that performs toner supply from the toner container to the sub hopper and toner from the sub hopper to the developing device using a common drive source. It is an object of the present invention to provide an image forming apparatus that can determine whether or not a toner container has a simple structure without providing a determination unit in the toner container.

  An image forming apparatus according to the present invention includes a toner container that is detachable from the apparatus body, a toner storage unit that is supplied with toner from the toner container, and a toner storage unit that is provided in the apparatus body. A developing device that receives the supply; a first detection unit that detects a toner amount in the toner storage; a second detection unit that detects a toner concentration in the development device; and a first toner supply unit provided in the toner container. , A second toner supply unit provided in the toner storage unit, and a common drive source for driving the first toner supply unit and the second toner supply unit, the toner amount in the toner storage unit and the toner concentration in the developing device Is an image forming apparatus that drives a drive source so that a predetermined set amount and a set value are obtained, and the first detection means detects that the toner amount in the toner storage portion is equal to or less than the set amount. Then, when the set value of the toner density in the developing device is set to a low value smaller than the normal value, and there is a possibility that the toner container is attached or detached, the drive source is driven to perform the first detection. When it is detected by the means that the amount of toner in the toner storage unit exceeds the set amount, it is determined that the toner container has been replaced with a new one, and the set value of the toner density in the developing device is returned to the normal value. It is characterized by that.

  Here, when the toner density in the developing device is set to a low value, it is preferable to display the replacement of the toner container on the display means.

  In addition, there is a possibility that the toner container may be attached or detached when the door provided in the apparatus main body is opened or closed, when the main power is turned on, or when recovering from the sleep mode that suppresses power consumption. Either case is preferred.

  Further, it is preferable that the amount of toner supplied from the toner container to the toner storage unit is larger than the amount of toner supplied from the toner storage unit to the developing device.

  In the image forming apparatus of the present invention, toner supply from the toner container to the sub hopper and toner supply from the sub hopper to the developing device are performed by a common driving source, and the toner amount in the toner storage unit by the first detection unit Since it is determined that the toner container has been replaced with a new one when the increase is detected, the apparatus can be reduced in size and weight. Further, when the toner container is discarded, the conventional separation work between the electronic component such as an IC chip and the container main body becomes unnecessary.

  In addition, when the toner container is replaced with a new one, the toner is supplied from the toner container to the toner storage unit, and at the same time, the toner is supplied from the toner storage unit to the developing device. Is set to a low value smaller than the normal value in advance, the toner density in the developing device is not likely to greatly exceed the normal value, and image quality is not deteriorated.

1 is a schematic diagram illustrating an example of an image forming apparatus according to the present invention. FIG. 3 is a perspective view illustrating an example of a toner bottle, a motor, and a sub hopper. FIG. 3 is a cross-sectional view of a main part showing a positional relationship between a toner bottle and a sub hopper. Operation | movement explanatory drawing of a sub hopper. 7 is a control flowchart for determining a new toner bottle.

  The image forming apparatus according to the present invention will be described below with reference to the drawings. However, the present invention is not limited to these embodiments.

  FIG. 1 is a schematic diagram showing an example of an image forming apparatus according to the present invention. The apparatus main body 1 of the image forming apparatus mainly includes an image reader unit 10 that reads a document image and a printer unit 20 that prints the read image. The image reader unit 10 is a known unit that reads a document placed on a document glass plate (not shown) by moving a scanner. The original image is color-separated into three colors of red (R), green (G), and blue (B), converted into an electrical signal by a CCD (Charge Coupled Device) image sensor (not shown), and R, G, B Image data is obtained.

  The image data for each color component obtained by the image reader unit 10 is subjected to various processes in the control unit 30 and reproduced in cyan (C), magenta (M), yellow (Y), and black (K). Converted to color image data.

  The image data is stored in the image memory 33 in the control unit 30 for each reproduction color, subjected to correction for positional deviation correction, and then read out for each scanning line in synchronization with the supply of the recording sheet. This is a drive signal for a light emitting diode provided as an exposure unit for image forming units 41Y, 41M, 41C, and 41K (hereinafter sometimes collectively referred to as “image forming unit 41”).

  The recording sheets are picked up one by one from the paper feed tray 61 by a paper feed roller 62 and sent in time with an intermediate transfer belt 53 described later.

  The intermediate transfer belt 53 is stretched between the driving roller 51 and the driven roller 52, and the driven roller 52 is urged to the left in FIG. 1 by a spring (not shown), thereby applying tension to the intermediate transfer belt 53. It has been. Then, the driving roller 51 is rotated counterclockwise by the transfer motor 54 controlled by the apparatus main body control unit 31. A resin material such as polycarbonate, polyimide, or polyimide amide is used for the intermediate transfer belt 53.

  Below the intermediate transfer belt 53, image forming sections 41 for yellow (Y), magenta (M), cyan (C), and black (K) are arranged at predetermined intervals. Transfer rollers 42Y, 42M, 42C, and 42K are disposed at positions that face the photosensitive drum of the image forming unit 41 with the intermediate transfer belt 53 interposed therebetween. A charging device, an exposure device, a developing device, and a cleaning device are disposed on the outer periphery of the photoconductive drum of the image forming unit 41. After charging the surface of the photoconductor, an electrostatic latent image corresponding to image data is obtained by the exposure device. An image is formed and toner is attached to the electrostatic latent image to form a toner image on the surface of the photoreceptor. The formed toner image is primarily transferred onto the intermediate transfer belt 53 when the intermediate transfer belt 53 passes between the photosensitive drum and the transfer rollers 42Y, 42M, 42C, and 42K. When the recording sheet pulled out from the paper feed tray 61 passes through the nip portion between the intermediate transfer belt 53 and the secondary transfer roller 55 through the broken line A, the toner image on the intermediate transfer belt 53 is recorded on the recording sheet. Secondary transferred on top. Thereafter, the recording sheet is conveyed to the fixing unit 80 where it is heated and pressurized to fix the toner image on the recording sheet. Then, the recording sheet on which the toner image is fixed is discharged outside the apparatus. On the other hand, the toner remaining on the surface of the photoreceptor is removed by the cleaning unit, and the residual toner on the intermediate transfer belt 53 is collected by the transfer belt cleaner 101 and stored in the waste toner box 102.

  Each of the developing devices 43Y, 43M, 43C, and 43K (hereinafter, sometimes collectively referred to as “developing device 43”) of the image forming unit 41 includes a sub hopper (toner storage unit) 70Y that replenishes a predetermined amount of each color toner. 70M, 70C, and 70K (hereinafter, collectively referred to as “sub-hopper 70”) are provided, and are supplied to the developing device 43 through joints 71Y, 71M, 71C, and 71K. Above the sub hopper 70, toner bottles (toner storage containers) 72Y, 72M, 72C, 72K (hereinafter may be collectively referred to as “toner bottle 72”) are detachably provided. When the remaining amount of toner in the sub hopper 70 decreases, toner is supplied from the toner bottle 72 to the sub hopper 70. When the toner in the toner bottle 72 runs out, the toner bottle 72 is replaced with a new one.

  The control unit 30 is provided with a new toner bottle determination unit 33 in addition to the apparatus main body control unit 31 and the image memory 33. The control operation of the new toner bottle determination unit 33 will be described later. Further, an operation display unit 90 is provided on the upper front surface of the apparatus main body 1 so that a user can input printing conditions and notify the current status of the apparatus, and a toner counter 91 is provided in a part of the operation display section 90. Displays information that serves as a guide for replacing the toner bottle, such as the date of installation and the cumulative number of prints.

  FIG. 2 is a perspective view of the sub hopper 70 and the toner bottle 72. The toner bottle 72 includes a bottle portion 722 that stores toner, a cap portion 723 having a supply port 723a (shown in FIG. 3) formed on the outer peripheral surface, and a shutter portion 725 (see FIG. 3) that opens and closes the supply port 723a. As shown). The bottle part 722 and the cap part 723 are relatively rotatably attached. A knob 724 for rotating the toner bottle 72 is formed on the front side of the cap portion 723. Each cap portion 723 of the toner bottle 72 provided for each color is an upper surface in which sub-hoppers 70Y, 70M, 70C, and 70K (hereinafter sometimes collectively referred to as “sub-hoppers 70”) for each color are integrally formed. Is placed.

  On the back side of the toner bottle 72, a drive source 721 for rotating the bottle portion 722 and the replenishing roller 703 (second toner supply means, shown in FIG. 3) of the sub hopper 70 is provided. Although not shown, the drive source 721 and the replenishing roller 703 are coupled by a connecting shaft, and the toner bottle 72 and the replenishing roller 703 of the sub hopper 70 rotate simultaneously. In the figure, only two drive sources 721 are shown, but the two-color toner bottle 72 and the replenishing roller 703 are driven by one drive source, and are switched by a clutch mechanism (not shown). It has become.

  When the bottle unit 722 is rotated by the driving source 721, the toner stored in the bottle unit 722 is caused to cap by the spiral groove 727 (first toner supply unit) formed on the inner peripheral surface of the bottle unit 722. To the supply port 723a. The toner is dropped and supplied from the supply port 723a to the sub hopper 70.

  FIG. 3 shows a schematic configuration diagram of the cap portion 723 and the sub hopper 70 of the toner bottle 72. The supply port 723 a of the cap part 723 is located at the upper part of the sub hopper 70. A float member 704 that detects the upper surface level of the toner is provided in the sub hopper 70 so as to be swingable about a shaft 704a. A cam 702 that rotates together with the stirring shaft is provided below the float member 704, and the float member 704 swings up and down by the rotation of the cam 702.

  FIG. 4 shows a variation state of the float member 704 corresponding to the toner amount. A floating body 704b is provided on the free end side of the float member 704, and moves up and down according to the upper surface level of the toner. A magnet 704 c is provided on the upper surface of the floating body 704 b, and an empty sensor (first detection means) 705 is attached to the outer surface of the sub hopper 70. A reed switch is used as the empty sensor 705, and an ON or OFF signal is obtained according to the position of the magnet 704c provided on the upper surface of the floating body 704b. When there is sufficient toner in the sub hopper 70, the float member 704 and the magnet 704c are positioned above (FIGS. 4A and 4B), and the empty sensor 705 is turned off. On the other hand, when the amount of toner in the sub hopper 70 is reduced, the upper surface of the toner is lowered, the float member 704 and the magnet 704c are lowered, and the empty sensor 705 is turned on. When the empty sensor 705 is turned on, the drive source 721 is driven, the bottle portion 722 of the toner bottle 72 is rotated for a predetermined time (for example, 10 seconds), and the toner is supplied from the toner bottle 72 into the sub hopper 70. As a result, the empty sensor 705 changes from an ON signal to an OFF signal.

  However, when there is no toner in the toner bottle 72, the toner is not replenished in the sub hopper 70 even if the bottle portion 722 is rotated. For this reason, the empty sensor 705 continues the ON signal. Therefore, for example, if the empty sensor 705 does not change from an ON signal to an OFF signal even when the bottle unit 722 is rotated for 10 seconds, it is determined that there is no toner in the toner bottle 72.

  On the other hand, the developing device 43 is provided with a toner concentration sensor (second detecting means) 431 (shown in FIG. 1) for detecting the toner concentration in the two-component developer, and the toner concentration in the developing device 43 is low. When this happens, the replenishing roller 703 of the sub hopper 70 rotates to maintain the predetermined toner density, and the developing device 43 is replenished with toner. For example, when the normal setting value of the toner density is 5%, when the toner density falls below 4.5%, the replenishing roller 703 rotates and toner is replenished from the sub hopper 70 to the developing device 43. At 5%, the replenishment roller 703 stops rotating.

  Here, in the image forming apparatus of the present invention, both the toner bottle 72 and the replenishing roller 703 of the sub hopper 70 are rotationally driven by the drive source 721, so that the replenishing roller 703 rotates simultaneously with the rotation of the toner bottle 72. On the other hand, as will be described later, in the image forming apparatus of the present invention, the toner bottle 72 is rotated, and it is determined whether the toner bottle 72 is new based on whether the toner is supplied from the toner bottle 72 to the sub hopper 70. Therefore, when determining whether or not the toner bottle 72 is new, the toner is also supplied from the sub hopper 70 to the developing device 43, and the toner is replenished even when the toner concentration in the developing device 43 is the normal set value. Will be. When the toner density in the developing device becomes higher than necessary, “fogging” or the like occurs and image quality deteriorates. Further, contamination inside the apparatus is likely to occur due to toner scattering.

  Therefore, in the present invention, when it is determined that there is no toner in the toner bottle 72, the set value of the toner density sensor 431 in the developing device is changed from a normal value (for example, 5%) to a lower value (for example, 4%). To do. Thus, when determining whether or not the toner bottle 72 is new, even if the toner is supplied from the sub hopper 70 to the developing device 43, it is avoided that the toner concentration becomes so high that a problem such as “fogging” occurs. . The low value of the toner density sensor 431 may be determined as appropriate within a range that does not adversely affect the image quality.

  Next, determination of whether the toner bottle 72 has been replaced with a new one will be described. In the image forming apparatus of the present invention, the toner bottle 72 is rotated, and whether or not the toner bottle 72 is new is determined based on whether or not the toner is supplied from the toner bottle 72 to the sub hopper 70. This determination time is when there is a possibility that the toner container is attached or detached. Specifically, when the door provided in the apparatus main body is opened and closed, when the main power source is turned on, when recovering from the sleep mode that suppresses power consumption, and the like. In these cases, if the toner bottle 72 is rotated and the empty sensor 705 changes from an ON signal to an OFF signal, it is determined that the toner container has been replaced with a new one.

  FIG. 5 is a flowchart showing an example of control of the image forming apparatus according to the present invention. If the ON signal of the empty sensor 705 is not canceled even after the toner bottle 72 is rotated for a predetermined time (step S1), it is determined that there is no toner in the toner bottle 72. First, the toner concentration sensor 431 of the developing device 43 is used. Is changed from a normal value to a low value (step S2). Then, normal image formation is continued as it is (step S3).

  By continuously performing normal image formation, the toner in the developing device is consumed, and when the toner density in the developing device falls below a low value (step S4), a toner bottle replacement display is displayed on the operation display unit 90 ( Step S5), prompting the user to replace the toner bottle 72. Further, the counting of the number of image formation is started (step S6).

  Next, when the door provided in the apparatus main body is opened / closed, when the main power supply is turned on, or when recovering from the sleep mode that suppresses power consumption (step S7), the toner bottle 72 is newly installed by the user. The toner bottle 72 is rotated by driving the drive source 721 (step S8). As a result, when the empty sensor 705 changes from an ON signal to an OFF signal (step S9), it is determined that the toner bottle 72 has been replaced with a new one, and the setting of the toner density sensor 431 of the developing device 43 is changed from a low value to a normal value. The value is returned (step S10). Then, the toner bottle replacement display on the operation display unit 90 is erased (step S11), the count of the number of formed images is reset to zero (step S12), and the control is terminated.

  On the other hand, if the empty sensor 705 remains ON even after the drive source 721 is driven to rotate the toner bottle 72 (step S9), it is determined that the toner bottle 72 has not been replaced with a new one. Then, the process returns to step S7 to wait for the possibility that the toner bottle 72 has been replaced with a new one. When this possibility occurs, the drive source 721 is driven to rotate the toner bottle 72 (step S7). S8) The control for determining whether or not the empty sensor 705 is changed from the ON signal to the OFF signal (step S9) is repeated.

  In addition, if image formation is repeated without the toner bottle 72 being replaced with a new one, the toner density in the developing device 43 may be reduced and the image quality may be affected. Therefore, there is a possibility that the toner bottle 72 has been replaced with a new one. Even if there is no image (step S7), if the number of images formed after the replacement display of the toner bottle 72 exceeds the predetermined number (step S13), the image formation is forcibly disabled (step S14). Then, the count of the number of formed images is reset to zero (step S12), and the control ends.

  In the control example described above, when the toner bottle 72 is rotated and toner is supplied from the toner bottle 72 to the sub hopper 70, the replenishing roller 703 is also rotated at the same time so that the toner is supplied from the sub hopper 70 to the developing device 43. Since the toner density in the developing device 43 has been lowered to a low value lower than the normal value in advance, even if the toner density increases by rotating the toner bottle 72, the toner density does not increase to a value that causes image quality defects. . Further, it is desirable to set the toner supply capability from the toner bottle 72 to the sub hopper 70 higher than the toner supply capability from the sub hopper 70 to the developing device 43.

  In the image forming apparatus of the present invention, toner supply from the toner bottle to the sub hopper and toner supply from the sub hopper to the developing device are performed by a common drive source, and an increase in the toner amount of the sub hopper is detected by the empty sensor. Since it is determined that the toner bottle has been replaced with a new one, the apparatus can be reduced in size and weight, which is useful. In addition, when the toner bottle is discarded, the conventional separation work between the electronic component such as an IC chip and the bottle body becomes unnecessary.

1 Device body (image forming device)
43 Developing Device 70 Sub Hopper (Toner Storage Unit)
72 Toner bottle (toner container)
90 display means 431 toner density sensor (second detection means)
705 Empty sensor (first detection means)
703 Replenishment roller (second toner supply means)
721 Drive source 727 Spiral groove (first toner supply means)

Claims (4)

A toner container detachably attached to the apparatus main body;
A toner storage unit provided in the apparatus main body, which receives supply of toner from the toner container;
A developing device that receives supply of toner from a toner storage unit;
First detection means for detecting the amount of toner in the toner storage unit;
A second detection means for detecting the toner density in the developing device;
First toner supply means provided in the toner container;
A second toner supply means provided in the toner storage unit;
A common drive source for driving the first toner supply means and the second toner supply means,
In an image forming apparatus that drives a drive source so that a toner amount in a toner storage unit and a toner density in a developing device become a predetermined set amount and set value,
When it is detected by the first detection means that the toner amount in the toner storage section is equal to or less than the set amount, the set value of the toner density in the developing device is set to a low value smaller than the normal value,
When there is a possibility that the toner container has been attached or detached, the drive source is driven, and when the first detection means detects that the toner amount in the toner storage unit exceeds the set amount, An image forming apparatus, wherein it is determined that the container has been replaced with a new one, and the setting value of the toner density in the developing device is returned to a normal value.   The image forming apparatus according to claim 1, wherein when the toner concentration in the developing device is set to a low value, the replacement of the toner container is displayed on the display unit.   Either the toner container may be attached or detached, the door provided on the main body of the device is opened or closed, the main power is turned on, or the device is restored from the sleep mode that suppresses power consumption. The image forming apparatus according to claim 1, wherein the image forming apparatus is a case.   The image forming apparatus according to claim 1, wherein a toner supply amount from the toner container to the toner storage unit is larger than a toner supply amount from the toner storage unit to the developing device.