JP2012103314A - Toner recovery device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner recovery device that provides increased accommodation rate of a toner container at a low cost, and accurately detects the amount of waste toner in the container instead of erroneously detecting that the container is full.SOLUTION: A toner recovery device includes: a screw 175 that conveys waste toner 23 on an intermediate transfer belt 30 to an exhaust port 176; a toner container 19 that has an opening 191 at an upper portion thereof and accommodates the waste toner 23 dropped from the opening 191; and a screw 18 that conveys the waste toner 23 conveyed to the exhaust port 176 by the screw 175 to the opening 191 of the toner container 19. The amount of toner conveyed by the screw 175 is larger than the amount of toner conveyed by the screw 18.

Description

  The present invention provides a permanent image on a transfer material by transferring a developer image (toner image) formed on an image carrier by an electrophotographic method onto a transfer material and then fixing it, for example, a copying machine, a printer, etc. The present invention relates to a waste toner collecting device of the image forming apparatus.

  2. Description of the Related Art Conventionally, there is known a color image forming apparatus configured to once transfer a toner image on the surface of a photosensitive drum to the surface of an intermediate transfer member and then transfer the toner image on the surface of the intermediate transfer member to a recording material again.

  Generally, the transfer efficiency of toner from an image carrier such as a photosensitive member or an intermediate transfer member to a recording material does not reach 100%, and therefore remains on the image carrier side. The toner remaining on the image carrier side is referred to as residual developer, that is, residual toner, and a cleaning unit or an external container connected to the cleaning unit is used as a toner container. Accumulated as waste toner.

  At this time, the powdery waste toner is piled up and stored in the toner container, and it is detected that the toner is full even though there is a free space. Further, the capacity of the toner container cannot be fully utilized, and the accommodation efficiency is poor. A method for preventing the waste toner accumulation surface in the toner container from being mountain-shaped is disclosed in Japanese Patent Application Laid-Open No. H10-228707. In this method, a rocking member is provided in the toner container, and the rocking member swings the powder toner in the toner container by the rocking member so that the powder toner is efficiently contained in the toner container. It is something to be stored.

  A method of swinging the entire toner container is disclosed in Patent Document 2. This method is provided with a swing mechanism that swings the toner container in conjunction with opening and closing of the door of the image forming apparatus.

Japanese Patent Publication No.63-32192 JP 11-133828 A

  In the methods described in Patent Documents 1 and 2, since there is a swinging member in the toner container, the structure of the entire toner recovery device becomes complicated and expensive. In addition, the vibration applied by opening and closing the door varies depending on the amount of toner in the toner container, so that the vibration applied to the toner container is different when the toner container is replaced or when the toner container is empty or has a small amount of toner. If the applied amount is large, abnormal noise will be generated. In addition, if the amount of vibration applied is small enough not to cause abnormal noise at this time, the amount of vibration applied is too small when the toner in the toner container is approaching full, so that improvement in target toner recovery efficiency and reliable full detection can be achieved. Sometimes it was not possible.

  In order to achieve the above object, the configuration of the present invention includes a first toner conveying means for conveying the residual toner on the image carrier to the discharge port, and a toner that has an opening at the top and falls from the opening. And a second toner conveying means for conveying the toner conveyed to the discharge port by the first toner conveying means to the opening of the toner container. The toner collecting device is characterized in that the amount of toner conveyed by the toner conveying means is larger than the amount of toner conveyed by the second toner conveying means.

  According to the above configuration, the massive toner accumulated in the second toner conveying means is dropped into the toner container. As a result, the toner accumulated in a mountain shape in the toner container is destroyed, and a dead space is not generated in the toner container, so that the toner can be efficiently stored.

1 is a schematic configuration diagram illustrating a configuration of an image forming apparatus including a toner recovery device according to the present invention. FIG. 3 is a cross-sectional explanatory view showing the configuration of the first embodiment of the toner recovery device according to the present invention. FIG. 3 is a perspective explanatory view showing a positional relationship between a toner container and an image forming apparatus main body in the first embodiment. FIGS. 3A to 3C are a front view, a left side view, and a rear view showing the configuration of the toner container in the first embodiment. FIG. 10 is a diagram illustrating a state in which toner accumulates in a mountain shape in a toner container according to a conventional configuration. FIG. 3 is a perspective explanatory view showing the configuration of the first embodiment of the toner recovery device according to the present invention. It is a figure which shows the relationship of the toner conveyance speed by the 1st, 2nd toner conveyance means which concerns on 1st Embodiment. FIG. 3 is a diagram illustrating a state in which massive toner drops and accumulates in the toner container according to the first embodiment. (A), (b) is a perspective explanatory drawing which shows the structure of 2nd Embodiment of the toner collection | recovery apparatus based on this invention. It is a figure which shows the relationship of the toner conveyance speed by the 1st, 2nd toner conveyance means which concerns on 2nd, 3rd embodiment of the toner collection | recovery apparatus which concerns on this invention. (A), (b) is a figure which shows the structure of the 2nd toner conveyance means of 3rd Embodiment of the toner collection | recovery apparatus based on this invention. (A), (b) is a figure which shows the structure of the 2nd toner conveyance means of 3rd Embodiment of the toner collection | recovery apparatus based on this invention. 10 is a flowchart illustrating operation control of a second toner conveying unit according to the third embodiment. It is a schematic block diagram explaining the structure of the image forming apparatus provided with 4th Embodiment of the toner collection | recovery apparatus concerning this invention. 10 is a flowchart illustrating operation control of a second toner conveying unit according to a fourth embodiment.

  Hereinafter, an image forming apparatus including a toner recovery device according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an image forming apparatus including a toner recovery device according to the present invention. First, the image forming process will be described with reference to FIG. When an image formation start signal is input, rotation of the image transfer member 30 that carries a toner image and serves as an intermediate transfer member, and the photosensitive drums 9M to 9K that also serve as image carriers are started. At this time, the intermediate transfer belt 30 is configured to contact the photosensitive drums 9M to 9K. In the image forming station 8M, it is charged to a predetermined charging potential V _D of the surface of the photosensitive drum 9M by the charging roller 10M. Image exposure (exposure potential V _L ) based on image information is performed on the surface of the charged photosensitive drum 9M by the exposure device 11M to form an electrostatic latent image.

  Next, the electrostatic latent image formed on the photosensitive drum 9M is developed with magenta toner (negatively charged toner) by the developing device 12M, and a magenta toner image is formed on the photosensitive drum 9M. This magenta toner image is electrostatically transferred to the intermediate transfer belt 30 by the primary transfer roller 13M.

  At this time, a predetermined voltage (positive voltage in this embodiment) is applied to the primary transfer roller 13M from the transfer power source to the primary transfer roller 13M. The toner remaining on the photosensitive drum 9M is collected by the cleaning device 14M. Such an image forming process to a transferring process are similarly repeated in the other image forming stations 8C, 8Y, and 8K. Then, the cyan toner image, yellow toner image, and black toner image formed on the photosensitive drums 9C to 9K are sequentially transferred onto the intermediate transfer belt 30 in a primary transfer.

  On the other hand, the transfer material 1 loaded on the feeding cassette 2 is fed by a feeding roller 16 and conveyed to a registration roller (not shown) in accordance with electrostatic latent image formation by exposure. Then, the transfer material 1 is conveyed to a contact nip portion N formed by the intermediate transfer belt 30 and the secondary transfer roller 34 by a registration roller in synchronization with the toner image on the intermediate transfer belt 30. Thereafter, the secondary transfer power source 35 applies a voltage having a polarity opposite to that of the toner to the secondary transfer roller 34, and the four colors carried on the intermediate transfer belt 30 on the transfer material 1 fed at a predetermined timing. The multiple toner images are secondarily transferred together. At this time, residual toner 22 remains on the intermediate transfer belt 30.

  Thereafter, the transfer material 1 is conveyed to a fixing device 15, and the toner image is heated and pressed on the transfer material 1 by the fixing device 15. The fixed transfer material 1 is placed on a discharge tray 3 provided outside the apparatus. The image forming process is completed. Hereinafter, in order to prevent the description from becoming complicated, the four image forming stations 8M, 8C, 8Y, and 8K of magenta, cyan, yellow, and black will be described as being representative of the image forming station 8, and related process means will be described. The same shall apply.

  Here, the toner collection device 17 that collects the waste toner 23 remaining on the intermediate transfer belt 30 (on the image carrier) that is an image carrier and is an intermediate transfer member, which is a feature of the present embodiment, will be described. FIG. 2 is a detailed view of the toner recovery device 17. Residual toner 22 remaining on intermediate transfer belt 30 is removed by toner recovery device 17 to prepare for the next cycle. A casing 171 having an opening 171a on the intermediate transfer belt 30 side, and a cleaning blade 172, which is a plate-like cleaning member made of urethane rubber, are attached to the opening 171a by a support member 173.

  The toner recovery device 17 is mounted on a support frame of the intermediate transfer belt 30 that is an intermediate transfer member, and the cleaning blade 172 abuts one edge so as to face the drive roller 33 with the intermediate transfer belt 30 in between. ing. When the residual toner 22 on the intermediate transfer belt 30 reaches the edge of the cleaning blade 172, it is scraped off. The residual toner 22 scraped off falls into the casing 171 as waste toner 23, and a screw 175 serving as a first toner conveying means for discharging the waste toner 23 moves from the front side to the back side in FIG. Then, the waste toner 23 is conveyed to the discharge port 176.

  That is, the screw 175 serving as the first toner transporting unit transports the residual toner 22 on the intermediate transfer belt 30 serving as the image carrier (on the image carrier) to the discharge port 176. The waste toner 23 discharged from the discharge port 176 falls into a duct 174 serving as a toner conveyance path. Then, the screw 18 serving as a second toner conveying means provided in the duct 174 has an opening 191 in the upper portion, and is conveyed to a toner container 19 that accommodates the waste toner 23 that has fallen from the opening 191. The That is, the screw 18 serving as the second toner transporting unit transports the waste toner 23 transported to the discharge port 176 by the screw 175 serving as the first toner transporting unit to the opening 191 of the toner container 19.

  Next, the configuration of the toner container 19 of the present embodiment will be described. FIG. 3 shows the positional relationship of the toner container 19 with the image forming apparatus main body 4, and FIGS. 4A to 4C are schematic configuration diagrams of the toner container 19. 4A is a front view of the toner container 19 (viewed from the direction of arrow a in FIG. 3), and FIG. 4B is a left side view (viewed from the direction of arrow b in FIG. 3). (C) is a rear view (view seen from the direction of arrow c in FIG. 3).

  The toner container 19 includes a storage unit 192 that stores the waste toner 23 and a detection unit 193 that determines whether or not the waste toner 23 is full. A toner container 19 is mounted on the image forming apparatus main body 4 so that the detection unit 193 can detect the optical sensor 194 provided on the image forming apparatus main body 4 side. The waste toner 23 falls freely from the opening 191 of the toner container 19 and is accumulated in the container 192. The accumulated waste toner 23 eventually reaches the detection unit 193, and the optical sensor 194 measures the transmitted light of the detection unit 193 to detect whether the waste toner 23 is full.

  Here, when the amount of toner supplied per unit time is small, the waste toner 23 that falls freely has no momentum, and the waste toner 23 collected in the toner container 19 does not collapse, as shown in FIG. It is deposited as a steep mountain. In this case, a lot of dead space is generated in the toner container 19, and the waste toner 23 cannot be efficiently collected in the toner container 19.

  In this embodiment, the screw 18 serving as the second toner conveying means is intermittently operated. As a result, a predetermined amount of waste toner 23 is accumulated in the duct 174 while controlling the amount of waste toner 23 accumulated in the duct 174 serving as a toner conveyance path provided with the screw 18. Then, when a predetermined amount of waste toner 23 is accumulated in the duct 174, the screw 18 serving as the second toner conveying means is continuously rotated to convey the massive waste toner 23 intermittently.

  As a result, the waste toner 23 accumulated in a mountain shape in the toner container 19 is destroyed, and a dead space is not generated in the toner container 19, and the waste toner 23 is efficiently stored. That is, in the present embodiment, the toner amount conveyed by the screw 175 serving as the first toner conveying unit is configured to be larger than the toner amount conveyed by the screw 18 serving as the second toner conveying unit. .

  Next, operations of the screw 175 serving as the first toner transport unit and the screw 18 serving as the second toner transport unit will be described. FIG. 6 is a perspective view showing the waste toner 23 until it reaches the opening 191 of the toner container 19 from the screw 175 serving as the first toner conveying means through the screw 18 serving as the second toner conveying means.

  The screw 175 serving as the first toner conveying means has the same drive source as the drive source of the intermediate transfer belt 30 (not shown), and always removes the waste toner 23 in the direction of arrow A while the intermediate transfer belt 30 is rotating. Transport to. The waste toner 23 that has reached the discharge port 176 of the screw 175 is discharged to the screw 18 serving as the second toner conveying means, and is conveyed in the direction of arrow B by the screw 18. Further, the screw 18 performs an intermittent operation in which the drive source 6 alternately stops and drives while the screw 175 is continuously operated. As the intermittent operation time, as shown in Table 1 below, the present inventors examined various combinations in consideration of variations in environment, paper type, image pattern, and the like.

  As shown in Table 1 above, conventional continuous rotation, 1.0 second stop / 1.0 second rotation, 2.0 second stop / 2.0 second rotation, 3.0 second stop / 3.0 second rotation In each of the intermittent operations, the lump of the waste toner 23 falling from the outlet 5 of the screw 18 serving as the second toner conveying means is small. Therefore, the mountain-shaped waste toner 23 in the toner container 19 cannot be destroyed. For this reason, a dead space is generated in the toner container 19.

  Further, in the intermittent operation of 10.0 second stop / 4.0 second rotation, the waste toner 23 is clogged at the discharge port 176 of the screw 175 serving as the first toner conveying means. Even in the intermittent operation of 10.0 second stop / 10.0 second rotation, if the amount of waste toner 23 is large, the waste toner 23 is clogged at the discharge port 176 of the screw 175 during the 10.0 second stop.

  In the present embodiment, the intermittent operation of the screw 18 serving as the second toner conveying means is set as follows. That is, a large lump of toner is dropped into the toner container 19, and the waste toner 23 is not clogged at the discharge port 176 of the screw 175 serving as the first toner conveying means. It was an operation. Alternatively, the screw 18 serving as the second toner conveying means is intermittently operated with 5.0 second stop / 5.0 second rotation. The intermittent operation time of the screw 18 serving as the second toner conveying means may not be equal to the stop time and the rotation time.

  FIG. 7 shows the amount of toner transport after a predetermined time of the screw 175 serving as the first toner transport unit and the screw 18 serving as the second toner transport unit. Since the screw 175 continuously rotates, the toner conveyance amount indicated by the vertical axis in FIG. 7 is proportional to the time indicated by the horizontal axis in FIG.

  Since the screw 18 operates intermittently, the toner conveyance amount at the time of rotation is proportional to the time, but the toner conveyance amount at the time of the stop is not changed even after the time has elapsed, and has a stepped shape as shown in FIG. Become a graph. That is, even if the stop time and the rotation time are not equal, if the respective toner transport amounts of the screws 175 and 18 are β1 and β2 at an arbitrary time α, the toner transport amounts β1 and β2 are {β2> β1}. As long as the relationship is established.

  That is, as shown in FIG. 7, the toner carrying capacity of the screw 18 serving as the second toner carrying means is controlled so as to increase the toner carrying ability of the screw 175 serving as the first toner carrying means. As a result, toner clogging does not occur in the toner transport path even if the screw 18 serving as the second toner transport means operates intermittently while the screw 175 serving as the first toner transport means operates continuously. Then, the lump waste toner 23 is intermittently conveyed by the screw 18 serving as the second toner conveying means, and the waste toner 23 accumulated in the mountain shape in the toner container 19 can be broken. This makes it possible to efficiently store the waste toner 23 without causing a dead space in the toner container 19.

  Here, the toner carrying capacity of the screws 18 and 175 is the toner per unit time in the respective screw shaft directions (the traveling direction of the waste toner 23 in each toner carrying path) when the screws 18 and 175 are continuously rotated. Refers to the transport amount. Therefore, in this embodiment, the high toner conveyance capability of the screws 18 and 175 means that the stroke length of one round of the screws 18 and 175 made of a spiral (spring-like) linear member having a high rotation speed per unit time is high. Long etc. For example, when the screws 18 and 175 are formed of spiral screw blades, the stroke length of one round of the spiral screw blade is long.

  As shown in FIG. 8, the waste toner 23 that has reached the outlet 5 of the screw 18 serving as the second toner conveying means becomes a lump-like waste toner 23 and freely falls into the toner container 19. Then, the waste toner 23 accumulated in a mountain shape in the toner container 19 is destroyed, and a dead space is not generated in the toner container 19, and the waste toner 23 can be efficiently stored.

  With the above configuration, the screw 18 serving as the second toner conveying means can cause the waste toner 23 to be clogged at the discharge port 176 of the screw 175 that is a relay portion with the screw 175 serving as the first toner conveying means. Absent. Then, the waste toner 23 can be accumulated and transported in the duct 174 serving as a toner transport path by intermittent operation.

  Accordingly, the lump waste toner 23 can be intermittently conveyed by the screw 18 serving as the second toner conveying means, and the waste toner 23 accumulated in the mountain shape can be broken. This makes it possible to efficiently store the waste toner 23 without causing a dead space in the toner container 19.

In the present embodiment, the screw 18 serving as the second toner conveying means has a first toner conveying speed X ₂ and a second toner conveying speed X ₂ ′ which are different from each other. The first toner conveying speed X ₂ slower than the toner conveying speed X ₁ of the screw 175 serving as the first conveying means. Then, the screw 175 is operating, the screw 18 serving as the second conveying means is controlled so as to operate a predetermined time at a first toner conveying speed X _2. This is a configuration different from the first embodiment and the first embodiment, and the other configurations are the same as the first embodiment.

Hereinafter, FIGS. 9A and 9B will be described with respect to the toner transport speeds X ₁ , X ₂ , and X ₂ ′ of the screws 175 and 18 serving as the first and second toner transport means that are the features of the present embodiment. It explains using. FIG. 9A shows a state in which the screw 175 serving as the first toner conveying means is continuously operated. The screw 175 continuously rotates at a rotational speed V ₁ [mm / sec] so as to transport the waste toner 23 at a toner transport speed X ₁ [mg / sec] in the direction of the arrow in FIG. At that time, the screw 18 serving as the second toner conveying means conveys the waste toner 23 at the first toner conveying speed X ₂ [mg / sec] in the direction of the arrow in FIG. 9 for a predetermined time Z [sec]. Rotate at the first rotation speed V ₂ [mm / sec].

FIG. 9B shows a state of the screw 18 as the second toner conveying means after a predetermined time Z [sec] has elapsed. The screw 18 as the second toner conveying means is conveyed at the first toner conveying speed X ₂ [mg / sec] at the first rotational speed V ₂ [mm / sec] for a predetermined time Z [sec]. During this time, it rotates continuously. Thereafter, the toner is continuously rotated at a second rotational speed V ₂ ′ [mm / sec] for a predetermined time Y [sec] so as to be transported at a second toner transport speed X ₂ ′ [mg / sec].

Next, the toner transport speeds X ₁ , X ₂ , X ₂ ′ [at the rotational speeds V ₁ , V ₂ , V ₂ ′ [mm / sec] of the screws 175, 18 as the first and second toner transport means. mg / sec] will be described with reference to FIG. Here, the toner transport speed is defined as the amount of toner transported per unit time during continuous rotation of the screws 175 and 18.

  Further, in the present embodiment, examination was performed by outputting an image pattern with a printing rate of 5% on LTR (letter) size Xerox 4200 (75 g) paper. As the shape of the screws 175, 18, the screw 175 has an outer diameter of 8 mm and a wire diameter of 1 mm, and the screw 18 has a spring shape with an outer diameter of 10 mm and a wire diameter of 1.5 mm. These conditions also apply to the following embodiments.

The toner conveyance speed by the screw 175 when the screw 175 serving as the first toner conveyance means continuously rotates at the rotation speed V ₁ [mm / sec] is defined as X ₁ [mg / sec]. The first toner conveyance speed by the screw 18 when the screw 18 as the second toner conveyance means continuously rotates at the first rotation speed V ₂ [mm / sec] is X ₂ [mg / sec]. To do. Then, the second toner conveyance speed by the screw 18 when the screw 18 as the second toner conveyance means continuously rotates at the second rotation speed V ₂ ′ [mm / sec] is X ₂ ′ [mg / sec. ]. At that time, as shown in FIG. 10, the relationship is {X ₂ ′> X ₁ > X ₂ }.

The screw 18 serving as the second toner conveying means has the first toner conveying speed X ₂ [mg / sec] when continuously rotating at the first rotation speed V ₂ [mm / sec]. It is slower than the toner conveying speed X ₁ [mg / sec] of the screw 175 as a means. The second toner conveyance speed X ₂ ′ [mg / sec] when continuously rotating at the second rotation speed V ₂ ′ [mm / sec] is the toner conveyance of the screw 175 serving as the first toner conveyance means. The spring shape (outer diameter, wire diameter) is higher than the speed X ₁ [mg / sec].

Next, a series of operations of the screw 175 serving as the first toner transport unit and the screw 18 serving as the second toner transport unit will be described. The drive source of the screw 175 serving as the first toner conveying means is common to a drive source (not shown) of the intermediate transfer belt 30 serving as the image carrier, and is driven to rotate in synchronization with the intermediate transfer belt 30. When the image formation start signal is inputted, the rotation of the intermediate transfer belt 30 is started, and the screw 175 serving as the first toner conveying means continuously rotates at the rotation speed V ₁ [mm / sec], and the toner conveyance speed X _1. Operates at [mg / sec].

At that time, the screw 18 serving as the second toner conveying means is configured to be operable independently of the screw 175 by a driving source 6 different from the screw 175. The screw 18 serving as the second toner conveying means continuously rotates at the first rotation speed V ₂ [mm / sec], and the predetermined time Z [sec] at the first toner conveyance speed X ₂ [mg / sec]. ] Operation (operation for a predetermined time).

Here, for a predetermined time Z [sec], as shown in FIG. 9B, the waste toner 23 is sufficiently placed in the duct 174 serving as a toner transport path provided with the screw 18 serving as the second toner transport means. It can be accumulated time. The amount of waste toner 23 accumulated in the duct 174 is {(X ₁ −X ₂ ) × Z} [mg].

Next, the screw 18 serving as the second toner conveying means is switched to a second toner conveying speed X ₂ ′ [mg / sec] that continuously rotates at a _second rotational speed V ₂ ′ [mm / sec], and is changed to a predetermined value. Operates for time Y [sec]. Here, the predetermined time Y [sec] is a time during which the waste toner 23 accumulated in the duct 174 serving as the toner transport path can be transported to the toner container 19 by the screw 18 serving as the second toner transport means. If the amount of the waste toner 23 accumulated in the duct 174 is {(X ₁ −X ₂ ) × Z} [mg] as described above, it can be calculated by the following equation ( ₁ ).

[Equation 1]
{(X ₁ −X ₂ ) × Z} [mg] ÷ X ₂ ′ [mg / sec] = Y [sec]

In this way, the screw 18 serving as the second toner conveying means is used for a predetermined time at the first toner conveying speed X ₂ [mg / sec] while the screw 175 serving as the first toner conveying means is continuously operating. Operates continuously for Z [sec]. Then, as shown in FIG. 9B, waste toner 23 is accumulated in a duct 174 serving as a toner conveyance path in which the screw 18 is provided. Thereafter, the second toner transport speed X ₂ ′ [mg / sec] is continuously operated for a predetermined time Y [sec], and the waste toner 23 accumulated in the duct 174 is transported in a large lump to accommodate the toner. Drop into vessel 19.

Incidentally, before the predetermined time Z, Y [sec] elapses during continuous operation of the screw 18 serving as the second toner conveying means at the first and second toner conveying speeds X ₂ , X ₂ ′ [mg / sec]. In some cases, the image forming operation ends. In this case, the elapsed time is stored in a non-illustrated nonvolatile memory, and the remaining waste toner 23 is continuously conveyed during the next image forming operation.

In the present embodiment, the waste toner 23 is not clogged at the discharge port 176 of the screw 175 serving as the first toner conveying means, and the duct 174 serving as the toner conveying path in which the screw 18 serving as the second toner conveying means is provided. The amount of waste toner 23 that can be accumulated was set to 5.0 [g]. Then, an example of when the toner conveying speed X ₁ of the screw 175 is set to 5.0 [mg / sec].

Second first toner conveying speed X ₂ of the conveying means and comprising a screw 18 is too late than the toner conveying speed X ₁ of the screw 175 serving as the first conveying means, the outlet 176 of the screw 175 As a result, the waste toner 23 is clogged. Therefore, the first toner conveying speed X ₂ of the screw 18 is in the range of 1.0 [mg / sec] ~3.0 [ mg / sec].

The second toner conveying speed X ₂ ′ of the screw 18 is set so that the waste toner 23 accumulated in the duct 174 serving as a toner conveying path in which the screw 18 is provided can be conveyed into the toner container 19 as a lump. Among them, if the second rotational speed V ₂ ′ is too fast, the load on the drive source 6 increases and the operating noise also increases.

For this reason, the second toner conveying speed X ₂ ′ of the screw 18 is set in the range of 20 [mg / sec] to 50 [mg / sec]. Accordingly, the toner conveyance speed X _{1 of the} screw 175 serving as the first toner conveyance means is set to 5.0 [mg / sec]. The first toner conveying speed X ₂ of the screw 18 serving as the second toner conveying means is set to 1.0 [mg / sec]. The second toner conveying speed X ₂ ′ of the screw 18 is set to 20 [mg / sec]. The amount of waste toner 23 that can be accumulated in the duct 174 serving as a toner conveyance path in which the screw 18 is provided is 5.0 g.

At this time, the time Z [sec] at the first toner transport speed X ₂ = 1.0 [mg / sec] and the time Y [sec] at the second toner transport speed X ₂ ′ = 20 [mg / sec]. Is calculated by the following equation (2). That is, Z [sec] = 1250 [sec] and Y [sec] = 250 [sec] are calculated by the following equation (2).

[Equation 2]
Z [sec] = 5000 [mg ] ÷ (X 1 -X 2) [mg / sec]
= 5000 [mg] / (5.0-1.0) [mg / sec]
= 5000 [mg] ÷ 4.0 [mg / sec]
= 1250 [sec]
Y [sec] = 5000 [mg] ÷ X ₂ ′ [mg / sec]
= 5000 [mg] ÷ 20 [mg / sec]
= 250 [sec]

  Accordingly, the screw 18 serving as the second toner transporting unit accumulates the waste toner 23 in the duct 174 serving as a toner transporting path in which the screw 18 is provided at time Z [sec] = 1250 [sec]. Then, at time Y [sec] = 250 [sec], the waste toner 23 accumulated in the duct 174 is conveyed in a large lump and dropped into the toner container 19 from the opening 191.

  With the above configuration, the waste toner 23 is accumulated and transported in the duct 174 without causing the waste toner 23 to be clogged in the duct 174 serving as a toner transport path provided with the screw 18 serving as the second toner transport means. I can do it. Accordingly, like the first embodiment, the massive waste toner 23 is intermittently conveyed by the screw 18 serving as the second toner conveying means. Then, the waste toner 23 accumulated in a mountain shape in the toner container 19 is destroyed. This makes it possible to efficiently store the waste toner 23 without generating a dead space in the toner container 19.

  In the present embodiment, a piezoelectric element 177 serving as a detecting unit that detects the amount (toner amount) of waste toner 23 accumulated in the vicinity of the outlet 5 of the screw 18 serving as a second toner conveying unit is provided. Then, the operation of the screw 18 is switched based on the detection result of the amount of waste toner 23 by the piezoelectric element 177, which is different from the first and second embodiments. When the waste toner 23 is deposited on the piezoelectric element 177, the piezoelectric element 177 can detect a pressure corresponding to the weight of the waste and convert it into a voltage, and can detect the amount of waste toner 23 (toner amount). .

  Hereinafter, the feature of the present embodiment is a configuration in which the amount of waste toner 23 accumulated near the outlet 5 of the screw 18 serving as the second toner conveying means is detected by the piezoelectric element 177 and the operation of the screw 18 is switched. Will be described with reference to FIGS.

  The amount of waste toner 23 is not necessarily constant depending on the type of transfer material 1, environment, endurance variation, and the like. Accordingly, as shown in FIGS. 11 and 12, a piezoelectric element 177 is provided in the vicinity of the outlet 5 of the screw 18 serving as the second toner conveying means, and the second toner conveying means is provided according to the amount of the waste toner 23. The operation of the screw 18 is controlled.

Next, the operation of the screw 18 serving as the second toner conveying means according to the amount of waste toner 23 will be described with reference to FIGS. 11, 12, and 13. FIG. In this embodiment, the toner conveying speed of the screw 18 serving as the second toner conveying means is selectively switched according to the amount of waste toner 23 at the outlet 5 of the screw 18. That is, the first toner transport speed X ₂ [mg / sec] and the second toner transport speed X ₂ ′ [mg / sec] which are different from each other are selectively switched. The first and second toner conveying speeds X ₂ and X ₂ ′ of the screw 18 serving as the second toner conveying means are the same as the toner conveying speed X of the screw 175 serving as the first toner conveying means as in the second embodiment. ₁ has a relation of {X ₂ ′> X ₁ > X ₂ }, as shown in FIG.

First, in step S1 of FIG. 13, it is determined whether or not the toner recovery device 17 is new. In step S1, if the toner recovery device 17 is new, the screw 18 serving as the second toner conveying means is operated at the second toner conveying speed X ₂ ′ [mg / sec] (step S2). Here, the screw 18 serving as the second toner conveying means is operated at the second toner conveying speed X ₂ ′ [mg / sec].

The reason is that when the toner collecting device 17 is in the initial state of the new product, the waste toner 23 does not exist in the image forming apparatus main body 4, and therefore, the duct 174 serving as a toner conveying path provided with the screw 18 serving as the second toner conveying means. It takes time for the waste toner 23 to reach the inside. Therefore, as the toner conveying speed of the screw 18 serving as a second conveying means, the first toner conveying speed X _{2 [mg} / sec] the second toner conveying speed X ₂ faster than _'[mg / sec] Set and transport waste toner 23.

  At this time, as shown in FIG. 11B, the waste toner 23 sent from the discharge port 176 of the screw 175 serving as the first toner conveying means is immediately sent to the toner container 19. For this reason, it is not accumulated in the duct 174 serving as the toner transport path of the screw 18 serving as the second toner transport means.

Next, in step S3, it is determined whether or not the weight M [mg] of the waste toner 23 accumulated on the piezoelectric element 177 is larger than the preset weight M ₁ [mg] of the first waste toner 23. To do. Here, the weight M ₁ [mg] of the _first waste toner 23 reaches the vicinity of the outlet 5 of the screw 18 through the screw 175 at the initial stage of the new toner recovery device 17 shown in FIG. It is the weight for judging whether or not. That is, it is the weight of the waste toner 23 deposited on the piezoelectric element 177, and in this embodiment, the preset weight M ₁ [mg] of the first waste toner 23 is 5 [mg]. did.

In step S3, when the weight M [mg] of the waste toner 23 is {M> M ₁ }, in step S4, the toner transport speed of the screw 18 serving as the second toner transport means is set to the first toner transport. to set the speed _{X 2.} Next, in step S5, it is determined whether or not the weight M [mg] of the waste toner 23 accumulated on the piezoelectric element 177 is larger than the preset weight M ₂ [mg] of the second waste toner 23. To do. Here, as shown in FIG. 10, the first toner conveying speed X ₂ of the screw 18 as the second conveying means is slower than the toner conveying speed X ₁ of the screw 175 serving as the first conveying means . Therefore, it is necessary to prevent the waste toner 23 from being clogged at the discharge port 176 of the screw 175.

The present inventors have studied, continuous printing screw 18 serving as the second conveying means in the first toner conveying speed X _2. At this time, when the waste toner 23 is clogged at the discharge port 176 of the screw 175 serving as the first toner conveying means, the amount of the waste toner 23 accumulated on the piezoelectric element 177 is 1.0 [g]. It was.

From these examination results, the weight M2 of the _second waste toner 23 has a sufficient margin for clogging of the waste toner 23 as shown in FIG. This is a weight for determining whether or not the waste toner 23 is accumulated. That is, the weight of the waste toner 23 accumulated on the piezoelectric element 177 is the weight of the waste toner 23. In this embodiment, the preset weight M ₂ [mg] of the second waste toner 23 is 500 mg. did.

In step S5, when the weight M [mg] of the waste toner 23 is {M> M ₂ }, in step S6, the toner transport speed of the screw 18 serving as the second toner transport unit is set to the second toner. The conveyance speed X ₂ ′ [mg / sec] is set. In this manner, the waste toner 23 accumulated in the duct 174 serving as a toner transport path provided with the screw 18 serving as the second toner transport means is transported into the toner container 19 all at once.

Next, in step S7, it is determined whether or not the weight M [mg] of the waste toner 23 accumulated on the piezoelectric element 177 is equal to or less than the preset weight M ₃ [mg] of the third waste toner 23. Here, the weight M ₃ [mg] of the third waste toner 23 is the waste toner remaining in the duct 174 slightly without being completely discharged by the screw 18 as in the discharge state shown in FIG. 23 is the weight of the waste toner 23 accumulated on the piezoelectric element 177.

In this embodiment, the preset weight M ₃ [mg] of the third waste toner 23 is set to 50 [mg]. The length of the screw 18 serving as the second toner conveying means (the length in the left-right direction in FIG. 12B) does not reach the piezoelectric element 177. Accordingly, all of the waste toner 23 accumulated in the screw 18 serving as the second toner conveying means is conveyed. Then, the waste toner 23 deposited on the piezoelectric element 177 in the vicinity of the outlet 5 of the duct 174 serving as a toner conveyance path in which the screw 18 is provided does not reach the conveyance force by the screw 18. As a result, a small amount stays on the piezoelectric element 177.

Finally, in step S7, when the weight M [mg] of the waste toner 23 is {M ≦ M ₃ }, in step S8, the toner conveyance speed of the screw 18 serving as the second toner conveyance means is set to the first. back of the toner conveying speed X _2, returns to the print standby. In this way, the operation of the screw 18 is switched according to the amount of waste toner 23 accumulated at the outlet 5 of the screw 18 serving as the second toner conveying means.

  As a result, the waste toner 23 is accumulated in the duct 174 serving as a toner conveyance path in which the screw 18 serving as the second toner conveyance means is provided, while extending the life of the drive source 6 and reducing the generated operation noise. Can be transported. Therefore, as in the above-described embodiments, the waste toner 23 accumulated in a mountain shape in the toner container 19 may be broken by intermittently transporting the bulk waste toner 23 by the screw 18 serving as the second toner transport means. I can do it. In addition, it is possible to efficiently store the waste toner 23 without generating a dead space in the toner container 19.

  In this embodiment, the amount of waste toner 23 accumulated in the vicinity of the outlet 5 of the screw 18 serving as the second toner conveying means is measured to control the operation of the screw 18. In addition, the amount of waste toner 23 (toner amount) accumulated in the vicinity of the discharge port 176 serving as the outlet of the screw 175 serving as the first toner conveying means is measured by the piezoelectric element serving as the detecting means, and the second toner is measured. You may control operation | movement of the screw 18 used as a conveyance means. Even in such a configuration, the same effect as in the present embodiment can be obtained.

  In the present embodiment, an acquisition unit that acquires image information carried on the intermediate transfer belt 30 serving as an image carrier is provided. Based on the image information acquired by the acquisition unit, the toner amount existing at the discharge port is estimated. Then, the operation of the screw 18 serving as the second toner conveying means is switched based on the estimation result, which is different from the above embodiments.

  Hereinafter, the configuration of the present embodiment will be described with reference to FIGS. In FIG. 14, the image controller 42 is constituted by a host computer or the like (not shown). A signal described in a specific description language is received, and signal processing for creating an electrostatic latent image is performed by an LD (Laser Diode; semiconductor laser) driver 44 of the image forming apparatus body 4. The LD driver 44 converts an electric signal into an optical signal, and irradiates the surface of the photosensitive drum 9 with the reflection mirror 7 by an optical signal reflected by a polygon mirror 45 attached to a polygon motor (not shown) that rotates at a high speed. .

  In the present embodiment, an LD (Laser Diode) lighting time coefficient in the image controller 42 is counted by the LD driver 44 and the printing rate integration circuit 43 in the engine unit. The image forming apparatus main body 4 starts the printing operation by sending a printing operation start signal (not shown) from the image controller 42 to the CPU (central processing unit) 41. The CPU 41 activates a polygon motor (not shown) to start the polygon mirror 45. Rotate.

  At this time, an LD (Laser Diode; semiconductor laser) is turned on, and a BD signal (beam detection signal) is generated by an output of a horizontal synchronization position detection sensor (not shown). This BD signal is a signal generated for each scan and is a reference signal for image formation. When the BD signal is input to the print rate integration circuit 43 shown in FIG. 14, the CPU 41 calculates an LD (Laser Diode) emission rate in one line by a measurement circuit (not shown).

  By repeating such operations, the lighting ratio of LD (Laser Diode; semiconductor laser) in one page can be easily calculated, and the cumulative lighting time (pixel count) can be obtained. The CPU 41 has a memory 40 and stores the pixel count. This value is a value p representative of toner consumption, which is obtained from the pixel count.

  Hereinafter, the control of the screws 175 and 18 serving as the first and second toner conveying means performed based on the number of printed sheets and the amount of toner consumption, which is a feature of the present embodiment, will be described with reference to the flowchart shown in FIG.

Initially, the image forming apparatus is a printed standby state, when printing is started, in step S11, calculates the number of printed sheets k and toner consumption t _k in accordance with the definitions set forth below. The toner consumption amount t _k [mg / sheet] at each printing count is defined as the toner consumption amount per printed sheet.

In the image forming apparatus of this embodiment, since the resolution is 600 [dot / inch], the area of one pixel, which is the minimum print area, is (25.4 [mm] / 600 [dot]) ² = 1.79 × 10. ⁻³ [mm ² / dot]. The amount of toner applied per unit area is 0.0050 [mg / mm ² ]. Therefore, the toner consumption t _k the number of printed sheets is calculated by Equation 3 below using the number of pixels p _k per sheet.

[Equation 3]
t _{k =} p _k × 1.79 × 10 ⁻³ × 0.0050

Then, more the toner consumption amount t _k per sheet obtained in Equation 3 and the number of printed sheets k, stored in the memory of the printer controller (not shown), integrating (step S12). Here, assuming that the current number of prints is the nth sheet, the total toner consumption Tn from the first sheet to the nth sheet is defined by the following equation (4).

  The toner consumption amount Tn [mg] per printed sheet up to the present is obtained by the above equation (4). In step S13, if the value of the toner consumption amount Tn [mg] satisfies the condition shown in the following formula 5, the process proceeds to step S14, and the operation of the screw 18 serving as the second toner conveying means is set to a predetermined special setting. To. If the value of the toner consumption amount Tn [mg] does not satisfy the condition shown in the following equation (5), the operation of the screw 18 serving as the second toner conveying means is not set to a special setting and the print standby state is resumed. .

[Equation 5]
Tn [mg] × 0.1> 500 [mg]

Next, the reason why the condition of the above formula 5 is determined will be described below. As a result of studies by the present inventors, when the total amount of waste toner 23 reaching the screw 175 is 500 [mg] or less, the waste toner 23 is accumulated in the screw 18 and conveyed in the normal continuous operation of the screw 18. It turns out that you can't. Therefore, in this embodiment, the toner consumption amount t _k, calculates the amount of the waste toner 23 that has reached the screw 175 serving as the first conveying means. Then, when the total amount of waste toner 23 reaching the screw 175 exceeds 500 [mg], the operation of the screw 18 serving as the second toner conveying means is set to a predetermined special setting.

In this embodiment, the transfer efficiency from the intermediate transfer belt 30 to the transfer material 1 is about 90% in consideration of various transfer conditions. Thus, (the amount of toner is formed as a toner image on the intermediate transfer belt 30) the toner consumption of approximately this time t _k can be estimated. The residual toner 22 remaining on the intermediate transfer belt 30 shown in FIG. 2 is about 10% in this embodiment. Therefore, in order for the total amount of residual toner 22 remaining on the intermediate transfer belt 30 to be 500 [mg], a toner image of 5 [g], which is 10 times the toner amount, is formed on the intermediate transfer belt 30. Need to be done.

Next, a special setting for the operation of the screw 18 serving as the second toner conveying means in the present embodiment will be described with reference to FIG. In step S13, if {toner consumption Tn [mg] × 0.1> 500 [mg]} is satisfied, the process proceeds to step S14, and the operation of the screw 18 serving as the second toner conveying means is set as a special setting. . The initial setting of the operation of the screw 18 serving as the second toner conveying means is an intermittent rotation operation. Alternatively, the second toner transport speed X ₂ ′, which is slower than the toner transport speed X ₁ of the screw 175 serving as the first toner transport means, is set.

The special setting of the operation of the screw 18 serving as the second toner conveying means in the present embodiment performs a continuous rotation operation. Alternatively, the toner transport speed X _t [mg / sec] is set to be equal to or higher than the toner transport speed X ₁ of the screw 175 serving as the first toner transport means. Further, the screw 18 serving as the second toner conveying means has a toner conveying speed X _t [mg / sec] when the screw 18 is specially set so that the toner conveying speed X _{1 of the} screw 175 serving as the first toner conveying means. The spring shape (outer diameter, wire diameter) is as described above.

Next, in step S15, the operation of the screw 18 is set to a special setting from the toner conveyance speed X _t [mg / sec] when the screw 18 is specially set and the operation time S [sec] of the screw 18. The transport amount As of the waste toner 23 is calculated by the following equation (6).

[Equation 6]
As [mg] = X _t [mg / sec] × S [sec]

  In step S16, if the transport amount As of the waste toner 23 obtained after the operation of the screw 18 obtained by the above formula 6 is specially set satisfies the condition of the following formula 7, the step S17 is performed. Then, the operation of the screw 18 is initialized. When the transport amount As of the waste toner 23 after the operation of the screw 18 obtained by the above equation 6 is specially set does not satisfy the condition of the following equation 7, the second toner transport unit The operation of the screw 18 is not initialized. Then, returning to step S15 again, the transport amount As of the waste toner 23 after the operation of the screw 18 is specially set is calculated by the following equation 6, and the steps S15 and S16 are repeated.

[Equation 7]
As [mg]> 550 [mg]

The reason for determining the condition of Equation 7 will be described below. The toner transport speed X _t [mg / sec] when the operation of the screw 18 serving as the second toner transport means is specially set is equal to or higher than the toner transport speed X _{1 of the} screw 175 serving as the first toner transport means. Therefore, if the screw 18 transports the waste toner 23 by 500 [mg] into the toner container 19, the amount of the waste toner 23 on the screw 175 serving as the first toner transport means is again 500 [mg] or less. become. Therefore, considering the margin of 50 [mg], {As [mg]> 550 [mg]} is set.

  Finally, in step S17, when the amount of the waste toner 23 on the screw 175 serving as the first toner conveying means becomes 500 [mg] or less again, the operation of the screw 18 serving as the second toner conveying means is initialized. Set and return to print standby. As described above, the image information carried on the intermediate transfer belt 30 serving as an image carrier is obtained by an obtaining unit including the image controller 42, the print rate integration circuit 43, the CPU 41, the memory 40, and the like.

  Based on the acquired image information, the amount of waste toner 23 present at the discharge port 176 is estimated. Based on the estimation result, the amount of waste toner 23 reaching the screw 175 serving as the first toner conveying means is estimated. Then, the operation of the screw 18 serving as the second toner conveying means is switched.

  Accordingly, the waste toner 23 can be efficiently conveyed while being accumulated by the screw 18 serving as the second toner conveying means while suppressing the cost. Accordingly, a large amount of toner is intermittently conveyed at once by the screw 18 serving as the second toner conveying means as in the above embodiments. Then, the waste toner 23 accumulated in a mountain shape in the toner container 19 is destroyed, so that no dead space is generated in the toner container 19 and the waste toner 23 can be efficiently stored.

  In each of the embodiments, the configuration in which the toner remaining on the intermediate transfer belt 30 as an image carrier is collected in the toner container 19 has been described. As another configuration, the present invention can be applied to a configuration in which residual toner on the photosensitive drum 9 as an image carrier is collected in a toner container provided in the cleaning device 14.

18 ... Screw (second toner conveying means)
19 ... Toner container
23… Waste toner
30 ... Intermediate transfer belt (image carrier)
175 ... Screw (first toner conveying means)
176… discharge port
191… opening

Claims (11)

First toner conveying means for conveying residual toner on the image carrier to the discharge port;
A toner container that has an opening at the top and stores toner dropped from the opening;
Second toner conveying means for conveying the toner conveyed to the discharge port by the first toner conveying means to the opening of the toner container;
Have
A toner collecting apparatus, wherein the amount of toner conveyed by the first toner conveying means is larger than the amount of toner conveyed by the second toner conveying means. The toner collecting apparatus according to claim 1, wherein the second toner conveying unit operates intermittently while the first toner conveying unit is continuously operated. When a predetermined amount of toner is accumulated in a toner conveyance path provided with the second toner conveyance means, the second toner conveyance means is operated to drop the toner from the opening to the toner container. The toner recovery device according to claim 1. 2. The toner recovery device according to claim 1, wherein the amount of toner accumulated in a toner conveyance path in which the second toner conveyance unit is provided is controlled by intermittently operating the second toner conveyance unit. . 5. The toner transport capability of the second toner transport unit is controlled so as to increase the toner transport capability of the first toner transport unit. 6. Toner recovery device. When a predetermined amount of toner is accumulated in a toner conveyance path provided with the second toner conveyance means, the second toner conveyance means is continuously operated to drop the toner from the opening to the toner container. The toner recovery device according to claim 4, wherein The second toner conveying means has a first toner conveying speed and a second toner conveying speed different from each other, and the first toner conveying speed of the second toner conveying means is the first toner conveying speed. The second toner conveying means operates for a predetermined time at the first toner conveying speed while the first toner conveying means is operating, being slower than the toner conveying speed of the toner conveying means. The toner recovery device according to 1. When a predetermined amount of toner is accumulated in the toner conveyance path in which the second toner conveyance means is provided, the second toner conveyance means is moved to the second toner conveyance speed higher than the toner conveyance speed of the first toner conveyance means. The toner collecting apparatus according to claim 7, wherein the toner is dropped from the opening to the toner container by operating at a toner conveying speed for a predetermined time. A detection unit for detecting the toner amount accumulated at the outlet of the first toner conveying unit or the toner amount accumulated at the outlet of the second toner conveying unit; and a detection result of the toner amount by the detecting unit The toner collection device according to claim 1, wherein the operation of the second toner conveying unit is switched based on the toner. It has an acquisition means for acquiring the image information carried on the image carrier, based on the image information acquired by the acquisition means, to estimate the amount of toner present in the discharge port, based on the estimation result, The toner recovery apparatus according to claim 1, wherein the operation of the second toner conveying unit is switched. An image carrier for carrying a toner image;
The toner recovery device according to any one of claims 1 to 10, wherein waste toner remaining on the image carrier is recovered.
An image forming apparatus comprising:

Images