Toner conveying device, developing device equipped with the same, and image forming device

Abstract

The present invention provides a toner conveying device and a developing device and an image forming device equipped with the toner conveying device. The toner conveying device includes a vertical conveying portion, a horizontal conveying portion, a conveying member and a loose member. The vertical conveying portion causes the toner or the developer containing the toner fed from the feed inlet connected to the main body side conveying passage to fall vertically and convey. The horizontal conveying portion is connected to the lower end of the vertical conveying portion, and the toner or the developer is conveyed in the horizontal direction by the conveying member arranged in the horizontal conveying portion. The loose member is arranged in a manner that it can move between a first position below the connection portion between the main body side conveying passage and the feed inlet, and a second position protruding upward from the connection portion, and moves back and forth in the vertical direction at the first position and the second position, respectively.

Description

Technical Field

[0001] The present invention relates to a colorant conveying device for conveying colorant, and in particular to a colorant conveying device having a colorant conveying portion connected to a horizontal conveying portion at the lower end of a vertical conveying portion that causes the colorant to fall in a vertical direction, and a developing device and an image forming device having the colorant conveying device. Background Art

[0002] An image forming device such as an electrophotographic printer or copier includes: a photosensitive drum that carries an electrostatic latent image; a developing device that develops the electrostatic latent image into a toner image by supplying toner to the photosensitive drum; and a toner container that replenishes toner to the developing device. In a color image forming device, a layout is sometimes adopted in which an intermediate transfer unit is inserted between the toner container and the developing device. In this case, since the toner container and the developing device are separated, a toner conveying unit is provided to convey the toner from the toner discharge port of the toner container to the toner loading port of the developing device.

[0003] In this case, as long as the toner container can be arranged directly above the developing device, the toner conveying section only needs to be provided with a vertical conveying section for causing the toner to fall vertically. However, due to layout constraints, when it is difficult to arrange the toner container directly above the developing device, the toner conveying section needs to be provided with a horizontal conveying section for conveying the toner in the horizontal direction in addition to the vertical conveying section. The horizontal conveying section is provided with a screw conveyor for conveying the toner.

[0004] In the toner conveying section where the horizontal conveying section is connected to the vertical conveying section, the toner aggregates near the lower end of the vertical conveying section (the connection section with the horizontal conveying passage), thereby causing a problem of preventing smooth toner replenishment. This is because the rotation of the screw conveyor pushes the toner near the lower end of the vertical conveying section back to the upper side, causing the toner to aggregate and form a mass (caking) to block the conveying passage. Summary of the invention

[0005] An object of the present invention is to provide a colorant conveying device and a developing device and an image forming device equipped with the colorant conveying device, wherein the colorant conveying device can suppress the agglomeration of the colorant in the vertical conveying portion of a colorant conveying portion having a vertical conveying portion and a horizontal conveying portion, and can also suppress the retention of the colorant in the connecting portion at the upper end of the vertical conveying portion.

[0006] The toner conveying device of the first structure of the present invention comprises: a vertical conveying part, the upper end of which is formed with a delivery inlet connected to the main body side delivery channel of the image forming device, so that the toner or the developer containing the toner delivered from the delivery inlet is vertically dropped and conveyed; a horizontal conveying part connected to the lower end of the vertical conveying part, and conveying the toner or the developer in a horizontal direction; a conveying member having a rotating shaft arranged in the horizontal conveying part along the conveying direction of the toner or the developer and a conveying protrusion protruding from the outer peripheral surface of the rotating shaft, and the rotating shaft is rotated to facilitate the toner or the developer to be conveyed. The conveying protrusion is used to convey the colorant or the developer in the horizontal conveying part along the direction of the rotating axis; and a loose member is arranged in the vertical conveying part and can move in the vertical direction. The colorant conveying device can be installed and removed relative to the image forming device. The loose member is configured to be able to move between a first position and a second position, the first position is located below the connection between the main body side conveying channel and the feed port, and the second position protrudes upward from the connection, and the loose member moves back and forth in the vertical direction at the first position and the second position respectively.

[0007] Furthermore, an image forming apparatus according to a second structure of the present invention includes the toner conveying device having the above structure.

[0008] In addition, the developing device of the third structure of the present invention includes: a developing container for storing a developer; a stirring and conveying member for stirring and conveying the developer in the developing container; and a developer carrier, which is rotatably supported by the developing container and carries the developer in the developing container, serving as a colorant replenishing portion for replenishing the colorant to the developing container, and is equipped with a colorant conveying device of the above structure.

[0009] Furthermore, an image forming apparatus according to a fourth structure of the present invention includes the developing device having the above structure.

[0010] According to the first configuration of the present invention, the interior of the vertical conveying section is in a state of performing a scraping action by the reciprocating movement of the loose member, so that the toner or developer in the vertical conveying section can be prevented from being agglomerated. In addition, by swinging the loose member between the first position below the connection section and the second position penetrating the connection section upward, the toner or developer can be prevented from being retained at the connection section between the main body side conveying passage and the delivery port without hindering the attachability and detachability of the main body side conveying passage relative to the image forming device.

[0011] Furthermore, according to the second aspect of the present invention, it is possible to provide an image forming apparatus capable of suppressing accumulation of developer and occurrence of malfunction due to the accumulation.

[0012] Furthermore, according to the third aspect of the present invention, it is possible to provide a developing device capable of suppressing accumulation of developer in the toner replenishing portion.

[0013] Furthermore, according to the fourth aspect of the present invention, it is possible to provide an image forming apparatus capable of suppressing the occurrence of image defects by smoothly and reliably replenishing toner to the developing device. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic cross-sectional view of an image forming apparatus 100 equipped with developing devices 3 a to 3 d connected to a toner replenishing unit 32 of the present invention.

[0015] Figure 2 It is a perspective view of the developing device 3 a mounted on the image forming apparatus 100 .

[0016] Figure 3 It is a cross-sectional side view of the developing device 3a.

[0017] Figure 4 This is a side view of the developing device 3 a as viewed from the toner replenishing portion 32 , and is a view showing a state in which the loosening member 50 is in the first position.

[0018] Figure 5 It is a longitudinal sectional view of the toner replenishing portion 32 and the stirring and conveying chamber 21 of the developing device 3 a , and is a view showing a state where the loosening member 50 is in the first position.

[0019] Figure 6 This is a side view of the loose member 50 as viewed from the opening direction of the annular portion 53 .

[0020] Figure 7 This is a side view showing another example of the loose member 50 in which the shape of the annular portion 53 is different.

[0021] Figure 8 This is a side view of the developing device 3 a as viewed from the toner replenishing portion 32 , and is a view showing a state in which the loosening member 50 is in the second position.

[0022] Fig. 9 It is a longitudinal sectional view of the toner replenishing portion 32 and the stirring and conveying chamber 21 of the developing device 3 a , and is a view showing a state where the loosening member 50 is in the second position.

[0023] Fig.10 This is a block diagram showing an example of a control path of the image forming apparatus 100 .

[0024] Fig.11 This is a flowchart showing an example of drive control of the developing devices 3 a to 3 d in the image forming apparatus 100 .

[0025] Fig.12This is a side view showing another example of the loose member 50 in which the first loose portion 51 and the second loose portion 52 have different shapes. DETAILED DESCRIPTION

[0026] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figure 1 The toner replenishing unit 32 of the present invention (see Figure 2 ) is a cross-sectional view of the internal structure of the image forming apparatus 100. In the main body of the image forming apparatus 100 (here, a color printer), from the upstream side in the conveying direction ( Figure 1 The image forming units Pa, Pb, Pc and Pd are arranged in sequence. The image forming units Pa to Pd correspond to different 4-color (yellow, cyan, magenta and black) image settings, and form yellow, cyan, magenta and black images in sequence through charging, exposure, development and transfer processes.

[0027] The image forming units Pa to Pd are provided with photosensitive drums (image carriers) 1a, 1b, 1c and 1d for carrying visible images (toner images) of different colors. Figure 1 An intermediate transfer belt (intermediate transfer body) 8 that rotates counterclockwise is provided adjacent to each of the image forming portions Pa to Pd.

[0028] When image data is input from a high-level device such as a personal computer, first, the main motor 75 (see Fig.10 ) starts the rotational drive of the photosensitive drums 1a to 1d. Then, the surfaces of the photosensitive drums 1a to 1d are uniformly charged by the charging devices 2a to 2d. Then, the exposure device 5 irradiates light according to the image data, and an electrostatic latent image corresponding to the image data is formed on each photosensitive drum 1a to 1d. The developing devices 3a to 3d are respectively filled with a predetermined amount of a two-component developer containing yellow, cyan, magenta and black toners. In addition, when the ratio of the toner in the two-component developer filled in each developing device 3a to 3d is lower than a predetermined value due to the formation of the toner image described later, the toner is replenished from the toner container 4a to 4d to each developing device 3a to 3d. The toner in the developer is supplied to the photosensitive drums 1a to 1d by the developing devices 3a to 3d, and is electrostatically attached to the photosensitive drums 1a to 1d. In this way, a toner image corresponding to the electrostatic latent image formed by the exposure of the exposure device 5 is formed.

[0029] Then, the primary transfer rollers 6a to 6d apply an electric field at a predetermined transfer voltage between the primary transfer rollers 6a to 6d and the photosensitive drums 1a to 1d, and the yellow, cyan, magenta and black toner images on the photosensitive drums 1a to 1d are primarily transferred to the intermediate transfer belt 8. The toner and the like remaining on the surfaces of the photosensitive drums 1a to 1d after the primary transfer are removed by the cleaning devices 7a to 7d.

[0030] The transfer paper P to which the toner image is secondarily transferred is stored in a paper cassette 16 disposed at the lower portion of the main body of the image forming apparatus 100. The transfer paper P is conveyed to the nip portion between the secondary transfer roller 9 and the drive roller 11 of the intermediate transfer belt 8 by means of a paper feed roller 12a and a registration roller pair 12b. A scraper-shaped belt cleaner 19 is disposed downstream of the secondary transfer roller 9 to remove residual toner and the like on the surface of the intermediate transfer belt 8.

[0031] The transfer paper P conveyed to the fixing section 13 is heated and pressurized by the fixing roller pair 13a, and the toner image is fixed on the surface of the transfer paper P, thereby forming a predetermined full-color image. The transfer paper P with the full-color image formed thereon is conveyed in a direction assigned by a forked section 14 that branches in multiple directions, and is discharged directly to a paper discharge tray 17 by a discharge roller pair 15 (or after being conveyed to a double-sided conveying passage 18 and forming images on both sides).

[0032] Figure 2 It is a perspective view of the developing device 3 a mounted on the image forming apparatus 100 . Figure 3 3a is a cross-sectional side view of the developing device 3a. Figure 2 2 shows a state where the cover member 20a of the developing container 20 and the developing roller 30 are removed. Figure 1 The developing device 3a is disposed in the image forming unit Pa, but the developing devices 3b to 3d disposed in the image forming units Pb to Pd have substantially the same structure as the developing device 3a, and thus description thereof is omitted. The developing devices 3a to 3d are attachable to and detachable from the image forming apparatus 100.

[0033] like Figure 2 and Figure 3 As shown, the developing device 3a is provided with a developing container 20 containing a two-component developer (hereinafter, also referred to as developer) containing a magnetic carrier and a toner. The developing container 20 includes: a cover member 20a; a partition wall 20b; a first connecting portion 20c, a second connecting portion 20d; a stirring and conveying chamber 21; a supply and conveying chamber 22 and a toner replenishing portion 32.

[0034] The cover member 20a is detachable from the main body of the developing container 20 and constitutes the upper portion of the developing container 20. The partition wall 20b divides the interior of the developing container 20 into a stirring and conveying chamber 21 and a supply and conveying chamber 22 arranged in parallel. The first connecting portion 20c and the second connecting portion 20d connect the stirring and conveying chamber 21 and the supply and conveying chamber 22 at both ends of the partition wall 20b in the long side direction.

[0035] In the stirring and conveying chamber 21 and the supply and conveying chamber 22, the toner is supplied from the toner container 4a (see Figure 1) The supplied toner is mixed and stirred with the magnetic carrier, and the stirring screw conveyor 25 and the supply screw conveyor 26 for charging are respectively arranged in a rotatable manner. In this embodiment, a two-component developer composed of a positively charged toner and a ferrite / resin coated carrier is used.

[0036] The stirring screw conveyor 25 has a rotating shaft 25a and a first conveying blade 25b formed in a spiral shape at a certain pitch in the axial direction of the rotating shaft 25a. The rotating shaft 25a and the first conveying blade 25b are integrally formed of synthetic resin. The first conveying blade 25b extends to both end sides of the stirring conveying chamber 21 in the long side direction to a position opposite to the first connecting portion 20c and the second connecting portion 20d. The rotating shaft 25a is rotatably supported by the first side wall portion 20f and the second side wall portion 20g of the developing container 20. The stirring screw conveyor 25 stirs the developer in the stirring conveying chamber 21 and conveys it in a predetermined direction (arrow A1 direction).

[0037] The supply screw conveyor 26 has a rotating shaft 26a and a second conveying blade 26b formed in a spiral shape at a certain pitch in the axial direction of the rotating shaft 26a. The rotating shaft 26a and the second conveying blade 26b are integrally formed of synthetic resin. The second conveying blade 26b has a length greater than the axial length of the developing roller 30 and extends to a position opposite to the first connecting portion 20c and the second connecting portion 20d. The rotating shaft 26a is arranged parallel to the rotating shaft 25a and is rotatably supported by the first side wall portion 20f and the second side wall portion 20g of the developing container 20. The supply screw conveyor 26 stirs the developer in the supply conveying chamber 22 and conveys it in the opposite direction (arrow A2 direction) to the stirring screw conveyor 25.

[0038] Then, the developer is moved in the axial direction (with respect to the developer) while being stirred by the stirring screw conveyor 25 and the supply screw conveyor 26. Figure 3 The developer is transported in a direction perpendicular to the paper surface) and circulates between the stirring and conveying chamber 21 and the supply and conveying chamber 22 by means of the first connecting portion 20c and the second connecting portion 20d formed at both ends of the partition wall 20b. That is, a circulation path of the developer is formed in the developing container 20 by the stirring and conveying chamber 21, the first connecting portion 20c, the supply and conveying chamber 22, and the second connecting portion 20d.

[0039] The developing container 20 is Figure 3 The developing roller 30 is arranged in the developing container 20 and in the upper right oblique direction of the supply screw conveyor 26. A portion of the outer peripheral surface of the developing roller 30 is exposed from the opening 20e of the developing container 20 and faces the photosensitive drum 1a with a predetermined gap (developing gap). Figure 3 The photosensitive drum 1a rotates counterclockwise during rotation (tracking rotation at a position relative to the photosensitive drum 1a).

[0040] The developing roller 30 includes: Figure 3 a cylindrical developing sleeve that rotates counterclockwise in the middle; and a magnet having a plurality of magnetic poles fixed in the developing sleeve (not shown). In addition, although a developing sleeve whose surface is rolled is used here, a developing sleeve whose surface is formed with a plurality of concave shapes (pits) and a developing sleeve whose surface is shot peened can also be used. Furthermore, a developing sleeve that is shot peened on the basis of rolling and forming concave shapes can also be used. A developing sleeve that is electroplated to improve durability and a developing sleeve that is treated with anti-corrosion aluminum can also be used. There is also a developing sleeve that is treated with a so-called secondary electrolytic coloring method in which the porous part of the anti-corrosion aluminum is treated with a metal salt such as Ni, Sn, or Mo after the anti-corrosion aluminum is processed. Using a developing voltage power supply 73 (refer to Fig.10 ) A developing voltage consisting of a DC voltage Vdc and an AC voltage Vac is applied to the developing roller 30.

[0041] In addition, on the developing container 20, the restricting scraper 27 is provided along the long side direction (with the same length as the developing roller 30) of the developing roller 30. Figure 3 A small gap (interval) is formed between the front end of the limiting scraper 27 and the developing roller 30. In this embodiment, a magnetic scraper made of stainless steel (SUS430) is used as the limiting scraper 27.

[0042] A toner concentration sensor 29 is disposed on the side of the stirring conveying chamber 21 so as to face the stirring screw conveyor 25. The toner concentration sensor 29 detects the toner concentration (mixing ratio of the toner relative to the carrier in the developer; T / C) in the developer in the developing container 20. As the toner concentration sensor 29, for example, a magnetic permeability sensor is used which detects the magnetic permeability of a two-component developer composed of the toner and the magnetic carrier in the developing container 20. In response to the toner concentration detected by the toner concentration sensor 29, the toner container 4a (refer to Figure 1 ) is replenished into the developing container 20 via the toner replenishing section 32.

[0043] The toner replenishing section 32 is provided on the upstream side of the developer conveying direction (arrow A1 direction) in the stirring conveying chamber 21. The toner replenishing section 32 includes a toner replenishing port 33, a vertical conveying section 34a, and a horizontal conveying section 34b (see Figure 4 , Figure 5 The toner replenishing port 33 opens at the upper portion of the toner replenishing portion 32 and is connected to the toner container 4a (see Figure 1 ) The main body side conveying passage 40 extending downward (refer to Figure 4 )connect.

[0044] Figure 4It is a side view of the developing device 3 a as viewed from the toner replenishing portion 32 side. Figure 5 It is a longitudinal sectional view of the toner replenishing portion 32 and the stirring and conveying chamber 21 of the developing device 3 a.

[0045] Figure 6 This is a side view of the loosening member 50 disposed in the vertical conveying portion 34 a of the toner replenishing portion 32 as viewed from the opening direction of the annular portion 53 .

[0046] like Figure 4 As shown, a drive input gear 63 is additionally provided at the end of the toner replenishing portion 32 of the developer container 20. The drive input gear 63 inputs a development drive motor 76 (see FIG. 1 ) to the stirring screw conveyor 25, the supply screw conveyor 26, and the development roller 30 of the development device 3a. Fig.10 )’s driving force.

[0047] The vertical conveying section 34a conveys the toner brought in from the toner supply port 33 in the vertical direction (makes it fall). The horizontal conveying section 34b extends horizontally below the vertical conveying section 34a, receives the toner from the vertical conveying section 34a, and conveys it in the horizontal direction. The horizontal conveying section 34b is opposite to the developer conveying direction (arrow A1 direction) in the stirring conveying chamber 21, from the upstream side ( Figure 5 The left side of the stirring and conveying chamber 21 is connected.

[0048] The rotating shaft 25a of the stirring screw conveyor 25 passes through the second side wall portion 20g of the developing container 20 and extends into the horizontal conveying portion 34b of the toner replenishing portion 32. A replenishing blade 25c formed in a spiral shape with a certain pitch in the axial direction of the rotating shaft 25a is integrally formed on the portion of the rotating shaft 25a disposed in the horizontal conveying portion 34b. The replenishing blade 25c is formed by a blade having the same winding direction (same phase) as the first spiral blade 25b, i.e., a spiral shape, and is formed with a smaller pitch and a smaller diameter than the first spiral blade 25b. That is, the stirring screw conveyor 25 also serves as a conveying member that conveys the toner in the horizontal conveying portion 34b toward the stirring conveying chamber 21.

[0049] The toner fed from the toner container 4a to the toner supply port 33 via the main body side conveying passage 40 falls to the horizontal conveying portion 34b through the vertical conveying portion 34a. The toner falling to the horizontal conveying portion 34b is transported in the horizontal direction ( Figure 5 The developer is transported to the right of the supply transport chamber 22 and enters the stirring transport chamber 21 along the rotating shaft 25a. Then, the developer is stirred and mixed with the developer in the stirring transport chamber 21 (the developer circulated from the supply transport chamber 22 through the second communicating portion 20d) to be charged with a predetermined charge amount.

[0050] A loose member 50 is disposed on the vertical conveying section 34a. The loose member 50 is formed by bending a metal wire (spring material) and has a first loose portion 51, a second loose portion 52, and an annular portion 53 in the shape of a coil spring (winding spring). The first loose portion 51 is disposed at the upper part of the vertical conveying section 34a, and the upper end portion is opposite to the toner replenishing port 33. The second loose portion 52 is disposed at the lower part of the vertical conveying section 34a, and the lower end portion is opposite to the replenishing blade 25c of the horizontal conveying section 34b. The outer diameters of the first loose portion 51 and the second loose portion 52 are smaller than the inner diameter of the vertical conveying section 34a.

[0051] The annular portion 53 is an elliptical shape that is long in the vertical direction, and its upper end is connected to the first loose portion 51, and its lower end is connected to the second loose portion 52. The annular portion 53 is mounted on an eccentric rotating shaft 60 that protrudes horizontally into the vertical conveying portion 34a.

[0052] A projection 61 is formed on a portion of the outer peripheral surface of the eccentric rotating shaft 60. The eccentric rotating shaft 60 is rotated by the same driving source (developer drive motor 76) as the stirring screw conveyor 25, the supply screw conveyor 26, and the developing roller 30. The inner diameter of the annular portion 53 is larger than the outer diameter of the eccentric rotating shaft 60, and the annular portion 53 and the eccentric rotating shaft 60 are engaged with a predetermined gap (play) in the vertical direction.

[0053] Figure 7 FIG. 5 is a side view showing another example of the loose member 50 having a different shape of the annular portion 53. The annular portion 53 may be any shape as long as it is open in the horizontal direction. Figure 7 However, in order to utilize the rotation of the eccentric rotating shaft 60 to smoothly move the loose member 50 back and forth, it is preferred that Figure 6 The oval shape shown may Figure 7 The edge portion of the inner peripheral surface shown is formed into a rectangular shape with rounded corners.

[0054] Next, the lifting and lowering operation of the loosening member 50 will be described. Figure 4 and Figure 5 25c. In the normal printing state, the loosening member 50 is located at a position close to the replenishing blade 25c (first position). Figure 4 and Figure 5 As shown, the toner in the horizontal conveying portion 34b does not contact the second loosening portion 52. Therefore, the loosening member 50 is supported by the eccentric rotating shaft 60. In addition, the first loosening portion 51 is located below the connection portion 41 between the toner replenishing port 33 and the main body side conveying passage 40.

[0055] When the eccentric rotating shaft 60 rotates in this state, the projection 61 contacts and leaves the inner peripheral surface of the annular portion 53 at a certain cycle. More specifically, the state in which the annular portion 53 is lifted by the projection 61 contacting the inner peripheral surface of the annular portion 53 and the state in which the annular portion 53 is lowered by its own weight by the projection 61 leaving are repeated. As a result, the loosening member 50 is located at the first position below the eccentric rotating shaft 60 in the gap between the annular portion 53 and the eccentric rotating shaft 60, and moves back and forth in the vertical direction in the vertical conveying portion 34a. In this way, the interior of the vertical conveying portion 34a is always in a state of performing a scraping action by the back and forth movement of the loosening member 50, so that the toner agglomeration in the vertical conveying portion 34a can be prevented before it occurs.

[0056] Figure 8 This is a side view of the developing device 3 a as viewed from the toner replenishing portion 32 , and is a view showing a state in which the loosening member 50 is in the second position. Fig. 9 It is a longitudinal sectional view of the toner replenishing portion 32 and the stirring and conveying chamber 21 of the developing device 3 a , and is a view showing a state where the loosening member 50 is in the second position.

[0057] like Figure 8 and Fig. 9 As shown, when the amount of developer in the toner replenishing portion 32 increases, the upward force generated by the contact of the developer G acts on the lower end of the second loose portion 52. As a result, the loose member 50 is lifted, and the gap between the annular portion 53 and the eccentric rotating shaft 60 moves to the second position located above the eccentric rotating shaft 60. When the loose member 50 is located at the second position, the first loose portion 51 protrudes upward from the connection portion 41 between the toner replenishing port 33 and the main body side conveying passage 40.

[0058] As a method for increasing the amount of developer in the colorant replenishing section 32, there can be listed a method in which the developer in the stirring conveying chamber 21 is caused to flow back to the horizontal conveying section 34b and be sent into the colorant replenishing section 32 by driving the stirring screw conveyor 25 of the developing device 3a to reverse and causing the replenishing blade 25c formed on the stirring screw conveyor 25 to reverse.

[0059] When the eccentric rotating shaft 60 rotates in this state, the projection 61 contacts and leaves the inner peripheral surface of the annular portion 53 at a certain cycle. More specifically, the state in which the projection 61 contacts the inner peripheral surface of the annular portion 53 and the annular portion 53 is pressed down, and the state in which the projection 61 leaves and the annular portion 53 is lifted up by the developer G are repeated. As a result, the loosening member 50 reciprocates in the vertical direction in the second position in the vertical conveying portion 34a.

[0060] Thus, the interior of the vertical conveying section 34a is in a state where a scraping action is performed by the reciprocating movement of the loosening member 50, thereby preventing the toner from clumping in the vertical conveying section 34a. In addition, by swinging the loosening member 50 at the second position where the first loosening section 51 passes through the connecting section 41 upward, the toner accumulation (toner clogging) that occurs in the connecting section 41 can be suppressed.

[0061] Therefore, the toner replenishment from the toner container 4a to the developing device 3a can be smoothly and reliably performed with a simple structure. In addition, the printing waiting time (downtime) of the image forming device 100 caused by poor toner replenishment can be minimized. In addition, since the loose member 50 is usually arranged in the first position, when the developing device 3a is installed or removed relative to the image forming device 100, the first loose part 51 will not interfere with the main body side conveying path 40, so that the installation and removal operation of the developing device 3a can be carried out smoothly.

[0062] Moreover, since the loose member 50 is moved up and down by the driving source shared with the developing device 3a, there is no need to provide a separate driving source for moving the loose member 50 back and forth, thereby effectively suppressing the clumping (agglomeration) of the colorant in the vertical conveying section 34a with a simple structure and at low cost.

[0063] Next, a control path of the image forming apparatus 100 of the present invention will be described. Fig.10 This is a block diagram showing an example of a control path used in the image forming apparatus 100 of the present invention. In addition, since the image forming apparatus 100 is used to perform various controls of various parts of the apparatus, the overall control path of the image forming apparatus 100 becomes complicated. Therefore, in the control path, the part necessary for implementing the present invention is mainly described.

[0064] The control unit 90 includes at least a CPU (Central Processing Unit) 91 as a central processing unit, a read-only storage unit, namely a ROM (Read Only Memory) 92, a readable and writable storage unit, namely a RAM (Random Access Memory) 93, a temporary storage unit 94 for temporarily storing image data, etc., a counter 95 for accumulating and counting the number of printed sheets, and multiple (here are 2) I / Fs (interfaces) 96 for sending control signals to each device in the image forming device 100 and receiving input signals from the operation unit 80.

[0065] ROM 92 stores control programs for image forming apparatus 100, numerical values ​​necessary for control, and data that does not change during use of image forming apparatus 100. RAM 93 stores necessary data generated during control of image forming apparatus 100 and data temporarily required for control of image forming apparatus 100.

[0066] In addition, the control unit 90 sends control signals from the CPU 91 to various parts and devices in the image forming apparatus 100 through the I / F 96. In addition, each part and device sends a signal indicating its state and an input signal to the CPU 91 through the I / F 96. As the various parts and devices controlled by the control unit 90, for example, there can be listed image forming units Pa to Pd, exposure device 5, primary transfer rollers 6a to 6d, secondary transfer roller 9, image input unit 70, voltage control circuit 71, main motor 75, development drive motor 76, toner supply motor 77, current detection unit 78, operation unit 80, etc.

[0067] The image input unit 70 is a receiving unit for receiving image data transmitted from a personal computer or the like to the image forming apparatus 100. The image signal input from the image input unit 70 is converted into a digital signal and then sent to the temporary storage unit 94.

[0068] The voltage control circuit 71 is connected to the charging voltage power supply 72, the developing voltage power supply 73 and the transfer voltage power supply 74, and the above-mentioned power supplies are operated by the output signal from the control unit 90. The above-mentioned power supplies are controlled by the control signal from the voltage control circuit 71. The charging voltage power supply 72 applies a charging voltage to the charging rollers (not shown) in the charging devices 2a to 2d. The developing voltage power supply 73 applies a developing voltage obtained by superimposing an AC voltage on a DC voltage to the developing rollers 30 in the developing devices 3a to 3d. The transfer voltage power supply 74 applies a predetermined primary transfer voltage and a secondary transfer voltage to the primary transfer rollers 6a to 6d and the secondary transfer roller 9, respectively.

[0069] The toner supply motor 77 rotates a toner replenishing screw (not shown) in the toner containers 4a to 4d to supply the toner stored in the toner containers 4a to 4d to the toner replenishing section 32 of the developing devices 3a to 3d via the main body conveying passage 40.

[0070] The current detection unit 78 detects the output current flowing through the toner supply motor 77 when the toner supply motor 77 is driven. The detection result is sent to the control unit 90. When toner clogging occurs in the connection portion 41 between the main body side conveying passage 40 and the toner replenishing portion 32 (toner replenishing port 33), the driving torque of the toner supply motor 77 increases due to the toner conveying load generated by the retained toner, so the output current of the toner supply motor 77 increases. By monitoring the output current value of the toner supply motor 77 by the current detection unit 78, the control unit 90 can detect the occurrence of toner clogging in the connection portion 41.

[0071] The operation unit 80 is provided with a liquid crystal display unit 81 and a light emitting diode 82 indicating various states. The user stops the image formation by operating the stop / clear button of the operation unit 80, and sets various settings of the image forming apparatus 100 to the default state by operating the reset button. The liquid crystal display unit 81 displays the state of the image forming apparatus 100, or displays the image formation status and the number of copies to be printed. Various settings of the image forming apparatus 100 are performed from the printer driver of the personal computer.

[0072] Fig.11 This is a flowchart showing an example of driving control of the developing devices 3a to 3d in the image forming apparatus 100. Figures 1 to 10 , press Fig.11 The following describes the execution steps of the toner loosening mode executed in the developing devices 3a to 3d.

[0073] The control unit 90 determines whether a print request is received from a high-level device such as a personal computer (step S1). If a print request is not received (step S1 is "No"), the print standby state is continued. If a print request is received (step S1 is "Yes"), a control signal is sent to the developing drive motor 76 to start driving the developing devices 3a to 3d (step S2). Then, at the same time as the image forming operation starts, the output current I of the toner supply motor 77 is detected by the current detection unit 78 (step S3).

[0074] The control unit 90 determines whether the output current I of the toner supply motor 77 reaches or exceeds a predetermined threshold value I1 (step S4). If I≧I1 (step S4 is "yes"), since toner clogging occurs in the connection portion 41 between the main body conveying passage 40 and the toner replenishing portion 32 of any of the developing devices 3a to 3d, the image forming operation is interrupted (step S5). Then, the developing drive motor 76 is reversed to execute a toner loosening mode for driving the developing device 3a to 3d in reverse where toner clogging occurs (step S6).

[0075] When the developing devices 3a to 3d are driven to rotate in reverse, the stirring screw conveyor 25 rotates in reverse, and the replenishing blade 25c formed on the stirring screw conveyor 25 also rotates in reverse. As a result, the developer in the stirring conveying chamber 21 flows back to the horizontal conveying portion 34b of the toner replenishing portion 32, pushing the loosening member 50 up to the second position (see Figure 8 In this state, the eccentric rotating shaft 60 is reversed, and the loosening member 50 moves back and forth up and down at the second position, so that the colorant clogging of the connecting portion 41 can be eliminated.

[0076] The control unit 90 determines whether a predetermined time has passed since the start of the reverse rotation (step S7). If the predetermined time has passed (step S7 is "yes"), the driving of the developing devices 3a to 3d to reverse is stopped, the toner loosening mode is terminated (step S8), and the developing devices 3a to 3d are driven to rotate forward to restart the image forming operation (step S9). On the other hand, if I < I1 in step S4 (step S4 is "no"), the toner loosening mode is not executed and the image forming operation is continued.

[0077] Subsequently, it is determined whether printing has been completed (step S10). If printing is to be continued (step S10 is "No"), the process returns to step S3, the image forming operation and the detection of the output current I of the toner supply motor 77 are continued, and the same control is repeated (steps S3 to S9). When printing is completed (step S10 is "Yes"), the process ends.

[0078] according to Fig.11 In the control example shown, when a toner blockage is detected in the connecting portion 41 during printing, the image forming operation is interrupted and the toner loosening mode is executed, so that the toner blockage can be quickly eliminated. In this way, insufficient toner supply due to toner blockage in the connecting portion 41 does not occur, and the density of the output image can be maintained constant. In addition, since the toner blockage is detected based on the output current of the toner supply motor 77, it is not necessary to provide a separate toner blockage detection mechanism, thereby reducing the number of parts and costs.

[0079] The present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the scope of the present invention. For example, the above-mentioned embodiment illustrates a loose member 50 having a first loose portion 51 and a second loose portion 52 in the shape of a coil spring. This is only an example. Fig.12 As shown, as the first loose portion 51 and the second loose portion 52, a loose member 50 having protrusions or strip-shaped protrusions radially extending from an axial core extending in the vertical direction may be used.

[0080] Furthermore, in the above-described embodiment, the developer in the developer container 20 is fed into the toner replenishing section 32 by driving the agitating screw conveyor 25 to rotate in reverse, and the loosening member 50 is moved to the second position. However, the method of increasing the amount of developer in the toner replenishing section 32 is not limited to driving the agitating screw conveyor 25 to rotate in reverse. For example, a bypass conveying passage connecting the developer container 20 and the toner replenishing section 32 is provided, and when the loosening member 50 is moved to the second position, the developer is fed from the developer container 20 to the toner replenishing section 32 via the bypass conveying passage.

[0081] In addition, in the above embodiment, the colorant clogging is detected based on the output current of the colorant supply motor 77 detected by the current detection unit 78, but a torque detection mechanism that directly detects the torque of the colorant supply motor 77 can also be provided to detect the colorant clogging based on the detection result of the torque detection mechanism.

[0082] In addition, the above embodiment describes a configuration in which toner is replenished to the developing devices 3a to 3d arranged in parallel with the stirring and conveying chamber 21 and the supply and conveying chamber 22, but it may also be a configuration in which toner is replenished to the developing devices 3a to 3d having the stirring and conveying chamber 21 and the supply and conveying chamber 22 arranged above the stirring and conveying chamber 21. In addition, in the above embodiment, an example in which the developer is supplied from the supply screw conveyor 26 to the developing roller 30 is shown, but the present invention is not limited thereto. A developer carrier such as a magnetic roller may be further provided between the supply screw conveyor 26 and the developing roller 30, and after the developer is supplied from the supply screw conveyor 26 to the magnetic roller or the like, only the toner is supplied from the magnetic roller or the like to the developing roller 30.

[0083] In addition, the above embodiment describes the toner replenishing section 32 for replenishing toner from the toner containers 4a to 4d to the developing devices 3a to 3d, but the toner conveying device of the present invention is not limited to the toner replenishing section 32 as long as the horizontal conveying section is arranged on the downstream side of the vertical conveying section. Figure 1 ) and the intermediate hopper for temporarily storing toner between the developing devices 3a to 3d can be applied to a toner conveying device for replenishing toner from the toner containers 4a to 4d to the intermediate hopper. Alternatively, it can also be applied to the toner conveying device for replenishing toner from the cleaning devices 7a to 7d (see Figure 1 ) A waste toner conveying device for conveying waste toner to a waste toner recovery container (not shown).

[0084] In addition, the present invention is not limited to Figure 1 The serial color printer shown can also be applied to various image forming devices such as digital or analog black and white copiers, black and white printers, color copiers, fax machines, etc., which have a colorant conveying device with a horizontal conveying section arranged on the downstream side of a vertical conveying section.

[0085] The present invention can be applied to a toner conveying device having a vertical conveying portion and a horizontal conveying portion connected to the lower end of the vertical conveying portion. The present invention can provide a toner conveying device that can suppress toner aggregation in the vertical conveying portion of the toner conveying device having a vertical conveying portion and a horizontal conveying portion, and can also suppress toner retention in the connecting portion at the upper end of the vertical conveying portion, and a developing device and an image forming device equipped with the toner conveying device.

Claims

1. A toner conveying device, characterized in that: include: A vertical conveying portion, wherein an inlet connected to a conveying passage on a main body side of the image forming device is formed at an upper end portion, so that the toner or the developer containing the toner fed from the inlet is vertically dropped and conveyed; A horizontal conveying portion connected to the lower end of the vertical conveying portion to convey the toner or the developer in a horizontal direction; A conveying member, comprising a rotating shaft arranged in the horizontal conveying portion along the conveying direction of the toner or the developer and a conveying protrusion protruding from the outer peripheral surface of the rotating shaft, wherein the toner or the developer in the horizontal conveying portion is conveyed in the direction of the rotating shaft by the conveying protrusion by rotating the rotating shaft; as well as The loose component is arranged in the vertical conveying part and can move in the vertical direction. The toner conveying device can be installed and removed relative to the image forming device. The loosening member is configured to be movable between a first position and a second position, wherein the first position is located below a connection portion between the main body side conveying passage and the delivery port, and the second position protrudes upward from the connection portion, and the loosening member moves back and forth in a vertical direction at the first position and the second position, respectively. The loose components include: A first loosening portion is arranged above the vertical conveying portion, with an upper end portion facing the delivery port; A second loosening portion is disposed at a lower portion in the vertical conveying portion, with a lower end portion facing the conveying member; and The annular portion connects the first loose portion and the second loose portion, and is engaged with the eccentric rotating shaft protruding horizontally in the vertical conveying portion with a predetermined gap in the vertical direction. The eccentric rotating shaft rotates while contacting the inner peripheral surface of the annular portion, so that the loosening member reciprocates in the vertical direction between the first position and the second position.

2. The toner conveying device according to claim 1, wherein: When the amount of the colorant or the developer in the horizontal conveying section is less than a specified value, the loose member is configured at the first position by its own weight. When the amount of the colorant or the developer in the horizontal conveying section reaches or exceeds a specified value, the loose member is pushed up by the colorant or the developer to be configured at the second position.

3. The toner conveying device according to claim 1, wherein: The first loose portion and the second loose portion are in the shape of a coil spring, and the annular portion is in the shape of an ellipse that is long in the vertical direction or a rectangle that is long in the vertical direction with the edges of the inner peripheral surface rounded off.

4. The toner conveying device according to claim 1, wherein: The eccentric rotating shaft is driven to rotate by a driving source common to the conveying member.

5. An image forming device, characterized in that: The toner conveying device comprises the toner conveying device as claimed in any one of claims 1 to 4.

6. A developing device, characterized in that: include: a developing container for storing a developing agent; a stirring and conveying member for stirring and conveying the developer in the developing container; as well as A developer carrier is rotatably supported by the developer container and carries the developer in the developer container. A toner supply unit for supplying toner to the developing container includes the toner conveying device according to any one of claims 1 to 4 .

7. The developing device according to claim 6, characterized in that: The conveying member and the stirring conveying member share the rotating shaft, By driving the conveying member to rotate reversely together with the stirring conveying member, the developer in the developing container is caused to flow back toward the toner replenishing portion and the loosening member is caused to reciprocate at the second position.

8. An image forming device, characterized in that: Comprising the developing device as claimed in claim 6 or 7.

Images