JP3752368B2 - Image forming apparatus - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, and a printer. More specifically, the thickness of a toner layer carried on a surface of a developer carrying member is restricted to a thin layer, and a latent image is developed with toner. It is related with the improvement of the means to provide the triboelectric charge for this.
[0002]
[Prior art]
For example, an electrophotographic image forming apparatus performs printing by the following process. That is, the surface of the photoreceptor is uniformly charged by the charging device, and an electrostatic latent image based on image information by the optical system is formed on the surface. Next, when the electrostatic latent image passes through the opposite position of the developing device, the latent image is visualized by adhesion of toner, superimposed on the recording material conveyed at the same time, and transferred using a transfer device. The toner image is transferred to a recording material. The transferred toner image is fixed on the recording material by passing through the fixing device. On the other hand, the residual toner is removed from the photoconductor after the transfer process by a cleaning device, and the residual charge on the photoconductor is neutralized by a static elimination device.
[0003]
As a developing device used in an image forming apparatus that performs such a series of processes, the toner stored in the interior is supported on the surface of the photosensitive member by a developer carrier having a magnet that is rotatably supported in the housing of the developing device. And making the latent image formed on the surface visible is widely put into practical use. In this type of developing device, the developer carrying member is used as a means for regulating the toner layer carried on the surface of the developer carrying member to a certain thickness and imparting a triboelectric charge to the toner to develop the latent image. A method of bringing a regulating member into contact with the surface of the body is widely used.
[0004]
On the other hand, in recent years, from the viewpoint of energy saving, low melting point toners (sharp melt toners) for performing the fixing at a temperature lower than the conventional temperature have been widely used as a visible image used for image formation. However, since the sharp melt toner easily adheres to the regulating member, toner fusion to the regulating member is likely to occur due to long-term use. For this reason, thickness unevenness occurs in the toner thin layer formed on the developer bearing member, and there arises a problem that density unevenness occurs in the formed image on the recording material. The toner fusion can be reduced by reducing the contact pressure between the developer carrying member and the regulating member. However, if the pressure is reduced, it becomes difficult to impart an appropriate amount of triboelectric charge to the toner. . Therefore, the regulating member is composed of a metal support member and a charge imparting layer having a polyamide elastomer adhered to the support member, so that an appropriate triboelectric charge amount can be obtained for the toner even when the pressure is reduced. A developing device that can be applied has been proposed (see, for example, Japanese Patent Laid-Open No. 9-50185).
[0005]
On the other hand, in recent years, with the improvement of the quality of the formed image, the necessity to make the particle diameter of the toner finer than before is increasing. In order to form such a thin layer of fine toner particles uniformly on the developer carrier, the contact pressure on the contact surface between the developer carrier and the regulating member must be made more uniform. I must. Accordingly, a roller-shaped reinforcing member is provided on the surface of the restricting member opposite to the contact surface, and the restricting member is attached to the restricting member in the direction of the developing roller as the developer carrier. A developing device that makes the contact pressure uniform is proposed (see, for example, 8-194373).
[0006]
[Problems to be solved by the invention]
By the way, in the developing devices of JP-A-9-50185 and JP-A-8-194373, the contact surface of the regulating member with the developing roller is at a fixed position. Also, toner accumulates at a fixed position on the surface of the regulating member on the downstream side in the developing roller rotation direction. When the deposited toner is left for a long period of time, it causes fusion that is difficult to dissociate from the surface of the regulating member, and new toner accumulates on the fused toner. As described above, since the contact surface is at a fixed position, the thickness of the toner layer deposited at a fixed position on the surface of the regulating member increases, and the toner layer thickness at the contact surface is prevented from being uniform. cause.
[0007]
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a developer carrying body for carrying and transporting a developer to a development area facing the latent image carrying body, and the developer carrying In an image forming apparatus using a developing device having a regulating member that regulates the layer thickness of the developer carried on the developer carrying body by contacting the body, a uniform and uneven thickness on the developer carrying body It is an object of the present invention to provide an image forming apparatus capable of stably forming a thin developer thin layer for a long period of time.
[0008]
[Means for Solving the Problems]
  In order to achieve the above object, the invention of claim 1 is characterized in that a developer carrying member for carrying and transporting a developer to a development region facing the latent image carrying member, and abutting against the developer carrying member. In the image forming apparatus using a developing device having a regulating member that regulates the layer thickness of the developer carried on the developer carrying member, the regulating member is a pressing member that pushes the developer carrying member, A charging support member sandwiched between the developer carrier and the pressing member;Provided is a rotatable rotating member that supports one end of the auxiliary charging member on the upstream side of the developer carrying member in the developer conveying direction with respect to the contact surface between the developing agent carrier and the auxiliary charging member. In addition, the other end portion of the auxiliary charging member is a free end that does not fix anything, and the rotation member rotates to wind the one end portion of the auxiliary charging member around the rotation member. The charging auxiliary member is reciprocated in the developer carrying direction of the developer carrying member by being fed out from the developer carrying member.It is characterized by this.
[0009]
  In the first aspect of the present invention, the developer deposited on the surface of the auxiliary charging member by moving the auxiliary charging member to the upstream side or the downstream side causes the auxiliary charging member, the developer carrier, and Move to a position that does not hinder the uniformity of the developer thin layer on the contact surface.
Further, when the auxiliary charging member moves to the upstream side of the developer carrying direction of the developer carrying member, the developer deposited on the surface of the auxiliary charging member contacts the charging auxiliary member and the developer carrying member. Move to the tangent surface. The developer that has moved to the contact surface is peeled off from the surface of the auxiliary charging member by being rubbed against the developer carrier. After the peeling, the charging auxiliary member moves to the downstream side of the developer carrying direction of the developer, so that the charging auxiliary member again comes into contact with the developer carrying body at the original position. Thus, the developer accumulated on the surface of the auxiliary charging member is removed by the reciprocating movement of the auxiliary charging member between the upstream side and the downstream side.
Further, the charging auxiliary member has a sheet-like structure that is more easily deformed than a thick block-shaped charging auxiliary member, and the shape change on the contact surface with the developer carrier is more than that of the block-shaped charging auxiliary member. Also grows. For this reason, the gap generated on the contact surface between the developer carrying member and the auxiliary charging member is made smaller than when the block-like auxiliary charging member is used.
Further, the charging auxiliary member is wound and fed by rotating the rotating member that supports one end of the sheet-shaped auxiliary charging member. When the winding and feeding are performed, the auxiliary charging member is moved to the upstream side or the downstream side. As described above, the movement of the auxiliary charging member is performed by the rotation of the rotating member.
[0018]
  Claim2The invention ofClaim 1In the image forming apparatus, in the developing deviceReplenishA developer cartridge for storing a replenishment developer is provided, and the charging auxiliary member and the developer cartridge are integrated.
[0019]
  ThisIn this invention, when the replenishment developer stored in the developer cartridge runs out, the developer cartridge is continuously replenished by replacing the developer cartridge with a new one. The charging auxiliary member is integrated with the developer cartridge, and at the time of replacement, the charging auxiliary member is also replaced with a new one at the same time. For this reason, when the developer cartridge is replaced, that is, when a certain amount of developer is consumed, the developer deposited between the auxiliary charging member and the developer carrier is removed.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the present invention is applied to an electrophotographic copying machine (hereinafter referred to as a copying machine) as an image forming apparatus will be described.
FIG. 1 is a schematic configuration diagram of a copying machine according to the present embodiment. The copying machine includes a scanner unit 20 for reading a document, an image processing unit 21 that electrically processes a digital signal output from the scanner unit 20, and an image based on the digital signal output from the image processing unit. Is formed on the transfer paper.
[0021]
In the scanner unit 20, an image of a document placed on the document table is read by an image reading device (not shown) via an irradiation lamp, a mirror, and a lens (not shown), and the data is read by the image processing unit. 21.
In the image processing unit 21, necessary processing is performed on this data, converted into an image signal, and sent to the printer unit 22.
[0022]
In the printer unit 22, the surface of the photosensitive drum 1 as an image carrier that is rotationally driven in the direction of arrow A in the drawing is uniformly charged by the charger 2. A latent image corresponding to the image of the document is formed on the surface of the photosensitive drum 1 by the exposure device 3 including a semiconductor laser, a polygon mirror, a reflection mirror, and the like based on an image signal from the image processing unit 21. . The latent image on the photosensitive drum 1 is developed with toner supplied from a developing roller 53 serving as a developer carrying member of the developing device 50 in the developing region P facing the developing device 50 to become a visible image. . The visible image is placed on a belt-like transport device 7 at a timing from a paper feed tray 5 by a registration roller 6 and transported to a portion facing the photosensitive drum 1, for example, transfer paper (not shown). 2) is transferred by the transfer device 8. At the time of the transfer, the number of copying is counted by a counter means (not shown). The transfer sheet on which the visible image has been transferred is transported by the transport device 7, and when passing through the fixing device 9, the visible image is fixed and discharged to the paper discharge tray 10. Untransferred toner remaining on the photosensitive drum 1 after the visible image transfer is cleaned from the photosensitive drum 1 by the cleaning device 11 and collected by the cleaning device 11. Then, residual charges are removed from the surface of the photosensitive drum 1 after cleaning by a charge removal lamp (not shown).
[0023]
The developing device 50 mainly includes a hopper portion 56 and a toner cartridge 60 as a developer replenishing container provided above the hopper portion 56. A toner replenishing port for replenishing toner is provided between the toner cartridge 60 and the hopper 56, and the toner in the toner cartridge 60 falls into the hopper 56 due to its own weight. In the hopper 56, in addition to the developing roller 53 described above, an agitator 55 as a stirring unit for stirring the toner and a supply roller 54 that contacts the developing roller 53 are provided. The agitator 55 conveys the toner onto the supply roller 54 while stirring the toner in the hopper 56.
[0024]
In the copying machine configured as described above, the line speeds of the photosensitive drum 1 and the developing roller 53 of the present embodiment are both 100 [mm / S].
[0025]
Next, an example in which the configuration of claims 1 to 6 is applied to the copying machine of this embodiment will be described in detail.
FIG. 2 is a schematic configuration diagram of a developing device used in the copying machine of the present embodiment. The developing roller 53 is opposed to the surface of the photosensitive drum 1 with a predetermined gap (hereinafter referred to as a developing gap G) in the developing area (P in FIG. 1), and an alternating electric field is formed by applying a bias voltage. Has been. The supply roller 54 rotates counterclockwise with respect to the developing roller 53, and the linear speed ratio = 0.9 and the biting amount = 1 [mm]. However, since the above values depend on the charging characteristics and supplyability of the toner, it is desirable to set the optimum conditions in a wider range. Further, the amount of biting of the supply roller 54 with respect to the developing roller 53 also depends on the characteristics of the motor that drives the two, so that the charging characteristics, the supply characteristics, and the motor characteristics should be set comprehensively. Is desirable. In addition, if the torque of the motor used in the image forming apparatus according to the present invention is in the range of 1 to 1.5 [kgfcm], it is considered that the motor can be operated without any problem.
[0026]
The supply roller 54 is made of urethane foam, is flexible, has a multi-cell structure with a diameter of 50 to 500 [μm], and has a structure that can easily carry the toner conveyed by the agitator 55. . The hardness is about 20 to 30 degrees according to JIS-A, is relatively soft, and the contact with the developing roller 53 is uniform. An AC bias is applied to the supply roller 54 to promote toner charging. In this embodiment, the toner on the supply roller 54 obtains a negative charge on the contact surface (hereinafter referred to as the contact surface) with the developing roller 53 that rotates in the counter direction relative to the rotation of the supply roller 54. And supported on the developing roller 3.
[0027]
The developing roller 53 is made of aluminum and is subjected to a blasting process in which uniform particles of metal (or glass) collide with the surface at high speed, thereby improving the toner conveyance performance. By the blasting process, the roughness of the surface of the developing roller 53 falls within the range of 1 to 4 [μm] in RZ. Since the surface roughness is 13 to 80% with respect to the toner particles, the toner particles are conveyed without being buried in the surface of the developing roller 53. As a processing method of the surface of the developing roller in the image forming apparatus according to the present invention, there is a processing method of performing coating processing with a resin or the like in addition to the above blast processing. In the above processing method, the quality of the surface of the developing roller can be kept constant for a long period of time, and the resin material is a silicon-based resin material with good toner charging or a Teflon-based resin material with good toner releasability. Is used. In addition, good toner conveying performance can be obtained even if processing is performed so that a part of the metal portion of aluminum is exposed by a special coating means. Further, a rubber material having a low hardness may be used as the material of the developing roller. In this case, if a relatively soft material having a hardness of about 15 to 40 degrees in JIS-A is used, the contact pressure between the developing roller and the supply roller can be made uniform along the axial direction of both rollers. it can.
[0028]
The toner carried on the developing roller 53 by the supply roller 54 has a non-uniform layer thickness, and is adhered in excess of the amount necessary for development [1 to 3 mg / cm.². Therefore, the charging auxiliary member 59 is sandwiched between the developing roller 53 and the pressing blade 52 that presses the developing roller 53, and the charging auxiliary member 59 is brought into contact with the developing roller 53 to form a thin layer of toner. . In the developing device used in the copying machine of this embodiment, there is no adhesive layer between the charging auxiliary member 59 and the pressing blade 52, and the charging auxiliary member 59 and the developing roller 53 come into contact with each other due to uneven thickness of the adhesive layer. There is no variation in pressure. For this reason, the thin layer thickness of the toner formed on the developing roller 53 can be made uniform.
[0029]
In this embodiment, the arrangement direction of the pressing blade 52 with respect to the developing roller 53 is a trailing direction, but the counter blade direction in which the free end of the pressing blade 52 is located on the upstream side of the developing roller 53 with respect to the fixed end. There may be. The pressing blade 52 is made of a material of SUS304 and a thickness of 0.1 [mm]. The pressing blade 52 is pressed against the developing roller 53 so that the pressure is 30 to 150 [g / cm] and the angle is 30 to 45 ° with respect to the tangent line between the developing roller 53 and the auxiliary charging member 59. Has been. As the material of the pressing member in the image forming apparatus according to the present invention, a metal such as stainless steel is used, the thickness is 0.1 to 0.15 [mm], and the free end length from the fixing holder is 10 to 15 [mm]. ] Is desirable. If the free end length exceeds the upper limit value, the size of the developing device increases. Therefore, it is necessary to secure a large arrangement space in the image forming apparatus. Since vibration is likely to occur during friction with the surface, density unevenness occurs in the formed image. Further, the pressing force of the pressing member to the developing roller is desirably in the range of 10 to 150 [g / cm]. When the upper limit is exceeded, the toner adhesion amount on the developing roller decreases and the toner charge amount becomes excessive. As a result, the density of the formed image is lowered. On the contrary, if the lower limit value is not reached, the toner thin layer is not uniformly formed and the toner lump passes through the contact surface, so that the quality of the formed image is remarkably lowered.
[0030]
The auxiliary charging member 59 is made of silicon and has a thickness of 0.2 [mm], and is configured in a sheet shape. As described above, the charging auxiliary member 59 is formed into a sheet shape, so that the structure is easily changed. Further, the surface roughness of the auxiliary charging member 59 is less than 1 [μm] in RZ, and the electric resistance is 10⁸[Ω · cm] is set. The auxiliary charging member of the image forming apparatus according to the present invention is made of a resin such as urethane or PET in addition to the above silicon, and has a thickness of about 0.2 [mm] and a surface roughness of 1 [μm in RZ. It is desirable that The electrical resistance is 10 due to dispersion of carbon or the like.^Five-10^TenAlthough it can be adjusted within the range of [Ω · cm], it is desirable to set it relatively high for the reason described later.
[0031]
A DC bias is applied to the pressing blade 52 described above, and an electric field having a polarity opposite to the developing electric field generated by the developing roller 53 is formed between the auxiliary charging member 59 and the developing roller 53 via the auxiliary charging member 59. The The value of the DC bias is V_Bl= V_Bl-V_Bl= 500 [V] and relatively high voltage. Therefore, an electric field can be formed between the auxiliary charging member 59 and the developing roller 53 by setting the electric resistance of the auxiliary charging member 59 relatively high. Under such application conditions, the toner existing between the auxiliary charging member 59 and the developing roller 53 and in the vicinity of the non-contact surface of both tends to reciprocate between the two. For this reason, the toner on the developing roller 53 is filled without any gap along the axial direction on the developing roller 53 before passing through the contact surface, and after the passage, excess toner is peeled off, A uniform thin layer with very little thickness variation can be formed. In the copying machine of this embodiment, the formed toner thin layer is 0.5 to 1 [mg / cm per unit area.²The toner charge amount was in the range of −5 to −20 [μC / g].
[0032]
In the copying machine of this embodiment, the diameter of the photosensitive drum 1 is 100 [mm] and the diameter of the developing roller is 16 [mm]. In this case, the area width of the developing area P is about 5 to 10 [mm]. Become. The latent image on the photosensitive drum 1 is developed with toner conveyed by the developing roller 53 within the range of the region width. The development gap in the development region P is 200 [μm]. Also, the AC bias peak-to-peak voltage (V_pp) Is a rectangular wave set to 400 [V], frequency is set to 4 [kHz], and Duty is 15 [%].
[0033]
FIG. 3 is a detailed view of the pressing blade 52, the developing roller 53, and the auxiliary charging member 59 in the developing device 50 used in the copying machine of this embodiment. The charging auxiliary member 59 has a sheet-like structure that is more easily deformed than the thick block-shaped charging auxiliary member, and the shape change on the contact surface with the developing roller 53 is larger than that of the block-shaped charging auxiliary member. For this reason, the gap generated on the contact surface between the developing roller 53 and the auxiliary charging member is made smaller than when the block-like auxiliary charging member is used. Further, the charging auxiliary member 59 is applied with a force for moving the developing roller 53 in the rotating direction on the contact surface. For this reason, the movement is prevented by supporting one end portion of the auxiliary charging member 59 located on the upstream side in the rotation direction from the contact surface by the rotating member 61 and applying tension.
[0034]
As shown in FIG. 3, the rotation member 61 is rotated by 60 ° at the maximum in the direction indicated by the solid line arrow and in the direction indicated by the dotted line arrow by a rotation drive system (not shown). By this rotation of the rotation member 61, the charging auxiliary member 59 is moved to the upstream side or the downstream side. Since the diameter of the rotating member 61 is 10 [mm], the distance of the movement is about 5.2 [mm] at the maximum. The rotation angle of the rotation member 61 per operation is 12 ° or 24 °. When the rotation member 61 performs one operation, the charging auxiliary member 59 is moved by 1.04 [mm] or 2.08 [mm]. The
[0035]
The portion where the toner is fused and accumulated on the auxiliary charging member 59 is within the range of 0.25 to 0.75 [mm] on the downstream side in the rotation direction of the developing roller 53 from the contact surface (hereinafter referred to as the accumulation range). The length of the contact surface is approximately the same as the distance corresponding to the entire axial direction of the developing roller 53 of the contact surface (hereinafter, the charging auxiliary member 59 corresponds to the accumulation range immediately after shipment from the factory). The surface is referred to as the primary fused surface). By rotating the rotating member 61 by 12 ° in the direction of the dotted line in the drawing, the toner fused and deposited on the primary fusing surface moves 1.04 [mm] upstream in the rotation direction of the developing roller 53 and develops. It contacts the roller 53. Due to this contact, a frictional force is generated between the toner and the developing roller 53, and the toner is peeled off from the auxiliary charging member 59. Further, after the peeling, by rotating the rotating member 61 by 12 ° in the direction of the solid line in the drawing, the primary fusing surface moves 1.04 [mm] downstream in the rotation direction of the developing roller 53. It is again located within the deposition range.
As described above, according to the copying machine of the present embodiment, the toner accumulated in the above range is removed, so that a uniform toner thin layer without uneven thickness can be stably formed on the developing roller 53 for a long period of time. Can do.
Further, since the charging auxiliary member 59 reduces the gap generated on the contact surface between the developing roller 53 and the charging auxiliary member, compared with the case where a thick block-shaped charging auxiliary member is used, the charging auxiliary member 59 is more uniform on the developing roller 53. A thin toner layer with a sufficient thickness can be formed.
In this embodiment, the auxiliary charging member 59 is reciprocated between the upstream side and the downstream side in the rotation direction of the developing roller 53. However, the charging auxiliary member 59 is moved to either the upstream side or the downstream side. Also good. In this case, by adjusting the rotation angle of the rotation member 61, the toner accumulated on the auxiliary charging member 59 is moved to a position that does not hinder the toner thinning on the contact surface, thereby making it uniform. Formation of a toner thin layer is realized.
[0036]
FIG. 4 is a flowchart showing the control operation in the copying machine of this embodiment. As shown in the figure, after the power of the copying machine is turned on, it is determined whether or not a signal of a power-off command for the copying machine has been received (step 100). When the signal is received, the print number counter value Pt, the rotation number counter value R1 of the rotation member 61, and the contact surface update operation counter value R2 are written in the EPP ROM, and then the power is turned off. (Steps 101 and 102). If the signal is not received, it is determined whether or not a copy operation command signal is received (step 103). If there is no copy operation command signal received, the operations after step 100 are performed again.
[0037]
If the copy operation command signal is received in step 103, a copy operation is performed (step 104), and Pt = Pt + 1 is set when copying of one sheet is completed (steps 105 and 106). Next, it is determined whether Pt = 400 (step 107). If Pt ≠ 400 [sheets], it is determined whether all copying operations have been completed (step 108). When all the copying operations are completed, the operations after step 100 are performed, and when all the copying operations are not completed, the operations after step 104 are performed.
In such a control operation, the copying machine of this embodiment performs a normal copying operation until Pt = 400, that is, until copying of 400 sheets of paper is performed.
[0038]
When the number of copied sheets reaches 400, that is, when Pt = 400, the rotating member 61 is rotated by −12 ° with respect to clockwise rotation (forward rotation) (step 109), and the auxiliary charging member 59 is moved. The developing roller 53 is moved 1.04 [mm] upstream in the rotation direction. By this movement, the toner fused and deposited on the primary fusing surface comes into contact with the developing roller 53 and is peeled off from the primary fusing surface by the rotation of the developing roller 53 (step 110). After the peeling, it is determined whether R1 is 9 or more (step 111). If R1 is not 9 or more, the rotating member 61 is rotated by 12 ° with respect to the normal rotation (step 112). By this rotation, the primary fused surface is again positioned within the above range. After the rotation, R1 = R1 + 1 and Pt = 0 are set (steps 113 to 114), and the operations after step 108 are performed.
With such a control operation, in the copying machine of this embodiment, the rotating member 61 is rotated every time 400 sheets of paper are copied, and the contact position of the auxiliary charging member 59 with the developing roller 53 is determined during the copying operation. Between the contact position and the primary fusing surface (hereinafter, the corresponding contact position at the time of copying immediately after factory shipment is referred to as an initial contact position). By this reciprocation and rotation of the developing roller 53, the toner fused and deposited on the primary fused surface is removed.
[0039]
When the charging auxiliary member 59 repeats the above-described reciprocation, the toner fused to the primary fused surface becomes difficult to be peeled off gradually. In addition, toner fusion / deposition occurs in the accumulation range when the primary fusing surface and the developing roller 53 are in contact with each other (hereinafter, within the accumulation range of the charging auxiliary member 59 at the time of the contact). The surface corresponding to is referred to as a secondary fusion surface). Therefore, when R1 is 9 in step 111, that is, when the number of rotations of the rotating member is the 10th, the rotating member 61 is rotated 24 ° clockwise (step 116). The auxiliary charging member 59 is moved 2.08 [mm] to the downstream side. By this movement, the contact position of the auxiliary charging member 59 with the developing roller 53 during the copying operation is moved 1.04 [mm] downstream of the initial contact position in the rotation direction of the developing roller 53. A new position that does not contact the developing roller 53 is set. After the rotating member 61 is rotated by 24 °, R1 and R2 are changed to 0 and R2 + 1, respectively (steps 117 and 118), and the operations after step 114 are performed. Therefore, in the copying machine of this embodiment, every time 4000 sheets of paper are copied, the contact position (hereinafter referred to as the contact position) of the auxiliary charging member 59 with the developing roller 53 at the time of copying is the downstream side. 1.04 mm.
[0040]
Before the operation of step 116 is performed, it is determined whether or not R2 = 4 so that the movement amount of the auxiliary charging member 59 from the initial contact position does not exceed 5.2 [mm] ( Step 115). In step 115, when R2 = 4, the display unit displays that it is necessary to replace the auxiliary charging member 59 (step 119), and then the operations in and after step 112 are performed. Therefore, after R2 = 4, that is, when the rotating member 61 has rotated 60 ° in the direction of the solid line arrow, the contact position at the time of copying is not updated.
In such a control operation, in the copying machine of this embodiment, every time the rotating member 61 rotates 10 times, the rotation of 24 ° is performed, and the contact position at the time of copying is changed. For this reason, the position of the toner accumulation layer formed on the auxiliary charging member 59 is changed to facilitate the removal of the toner from the accumulation layer.
[0041]
By repeating the above control operation, the rotation member 61 rotates at a maximum of 60 ° in the direction of the arrow shown in the drawing, and the contact position of the auxiliary charging member 59 with the developing roller 53 is the maximum from the initial contact position. Also, the developing roller 53 moves to the downstream side of 5.2 [mm] in the rotation direction. Accordingly, the exchange cycle of the rotating member 61 is 49 [operation] × 400 [sheets] = 19600 [sheets], that is, every time 19600 sheets are copied, stable image quality can be obtained for a long period of time.
[0042]
FIG. 5 is a plan view of the developing roller 53, the charging auxiliary member 59, and the rotating member 61 inside the developing device used in the copying machine of this embodiment as viewed from above. In this figure, the pressing member 52 is removed for easy viewing. As shown in the drawing, the auxiliary charging member 79 and the rotating member 11 are reciprocated in the direction of the arrow in the drawing by driving means (not shown). The driving means is realized, for example, by fixing a spring at one end of both members, fixing a thread-like member at the other end, and pulling the thread-like member back by a rotating member. It can also be realized by repeating contact and separation of the rack and pinion tooth tips on the other end. The distance of such reciprocating motion of the auxiliary charging member 59 is about several [mm], and the cycle is set to about 0.5 [second], that is, about 2 [Hz]. By the reciprocating motion, a toner lump generated between the developing roller 53 and the auxiliary charging member 59 is broken, and the fluidity of the toner between the two is increased. For this reason, fusion of toner to the auxiliary charging member 59 is reduced, and toner accumulation between the auxiliary charging member 59 and the developing roller 53 hardly occurs.
As described above, according to the copying machine of this embodiment, toner accumulation between the auxiliary charging member 59 and the developing roller 53 is difficult to occur, so the toner thin layer thickness formed on the developing roller 53 is uniform. Can be stably performed for a long time.
[0043]
Next, an example in which the configuration of claim 6 is applied to the copying machine of the above embodiment will be described.
FIG. 6 is a detailed view of the toner cartridge 60a and the auxiliary charging member 59a of the developing device used in this embodiment. As shown in the figure, the auxiliary charging member 59a is fixed to the toner cartridge 60a, and both are integrally formed. For this reason, when the toner cartridge 60a is replaced, the auxiliary charging member 59a is also replaced at the same time. Therefore, when a certain amount of toner is consumed, the toner accumulated between the auxiliary charging member 59a and the developing roller 53 is removed. The durability of the auxiliary charging member 59a depends on the material and the characteristics of the toner, but the quality of the copy of 2000 to 4000 sheets as a toner cartridge replacement cycle can be sufficiently maintained.
[0044]
When the toner cartridge 60a is replaced, the auxiliary charging member 59a is pressed against the developing roller 53 by the pressing member 52, but can be pulled out with a sufficiently weak force by pulling the toner cartridge 60a in the direction of the arrow in FIG. Is possible. When the new auxiliary charging member 59a is sandwiched between the pressing member 52 and the developing roller 53, the free end of the auxiliary charging member 59a is first inserted between the pressing member 52 and the developing roller 53, and then developed. By rotating the roller 53 a predetermined number of times, the auxiliary charging member 59 a is moved in the rotation direction of the developing roller 53 and is sandwiched between the pressing member 52 and the developing roller 53.
[0045]
FIG. 7 is a flowchart showing the control operation in the copying machine of this embodiment. As shown in the figure, in the copying machine of the present embodiment, a cartridge replacement work start command signal is received while waiting for reception of a copy operation command signal, and when the start command signal is received, Is activated (steps 206 to 210).
[0046]
In the above configuration, in the copier of this embodiment, when the replenishment toner stored in the toner cartridge 60a runs out, the replenishment of toner into the developing device is continued by replacing the toner cartridge 60a with a new one. The The charging auxiliary member 59a is integrated with the toner cartridge 60a, and at the time of the replacement, the charging auxiliary member 59a is also replaced with a new one at the same time. Therefore, when a certain amount of toner is consumed, the toner accumulated between the auxiliary charging member 59a and the developing roller 53 is removed.
[0047]
As described above, according to the present exemplary embodiment, the toner accumulated between the auxiliary charging member 59a and the developing roller 53 is removed when a certain amount of toner is consumed. The thickness of the thin layer can be made uniform over a long period of time.
[0048]
【The invention's effect】
  According to the first aspect of the present invention, the developer deposited on the surface of the auxiliary charging member is positioned so as not to hinder the uniformization of the thin developer layer on the contact surface between the auxiliary charging member and the developer carrying member. Since it moves, there is an excellent effect that it is possible to stably form a uniform developer thin layer without uneven thickness on the developer carrying member for a long period of time.
Further, since the developer deposited on the surface of the auxiliary charging member is removed, it is possible to stably form a uniform thin developer layer without uneven thickness on the developer carrier for a long period of time. effective.
Further, since a gap generated on the contact surface between the developer carrying member and the charging auxiliary member is made smaller than in the case of using a thick block-shaped charging auxiliary member, more uniform on the developer carrying member. A thick developer thin layer can be formed.
Further, since the charging auxiliary member is moved by the rotation of the rotating member, there is an excellent effect that the moving means can be facilitated.
[0053]
  Claim2According to the invention, when a certain amount of developer is consumed, the developer deposited between the auxiliary charging member and the developer carrier is removed, so that the developer carrier has a uniform thickness. There is an excellent effect that a developer thin layer without unevenness can be stably formed for a long period of time.
[0054]
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a copier according to an embodiment.
FIG. 2 is a schematic configuration diagram of an embodiment in which the configuration of claims 1 to 5 is applied to a developing device used in the copier.
FIG. 3 is a detailed view of the developing device.
FIG. 4 is a flowchart showing a control operation in a copying machine using the developing device.
FIG. 5 is a plan view of a developing roller 53, a charging auxiliary member 59, and a rotating member 61 in the developing device as viewed from above.
FIG. 6 is a detailed view of a toner cartridge 60a and a charging auxiliary member 59a in an example in which the configuration of claim 6 is applied to the developing device used in the copying machine of the embodiment.
FIG. 7 is a flowchart showing a control operation in a copying machine using the developing device of the embodiment.
[Explanation of symbols]
1 Photosensitive drum
2 Charger
3 Exposure equipment
5 Paper tray
6 Registration roller
7 Transport device
8 Transfer device
9 Fixing device
10 Output tray
11 Cleaning device
20 Scanner section
21 Image processing unit
22 Printer section
50 Developer
52 Pressing blade
53 Developing roller
54 Supply roller
55 Agitator
56 Hopper
57 Development bias power supply
58 Supply bias power supply
59 Charging Auxiliary Member
60 toner cartridge
61 Rotating member
62 Thin bias power supply

Claims (2)

The developer carrying member that carries and transports the developer to the developing area facing the latent image carrying member, and the developer carrying member that is carried on the developer carrying member can be made to have a layer thickness by contacting the developer carrying member. In an image forming apparatus using a developing device having a regulating member for regulating,
The regulating member includes a pressing member that presses the developer carrier, and a sheet-like charging auxiliary member that is sandwiched between the developer carrier and the pressing member, and the developer carrier and the Provided is a rotatable rotating member that supports one end of the charging auxiliary member on the upstream side of the developer carrying member in the developer transport direction with respect to the contact surface with the auxiliary charging member. The other end is a free end that does not fix anything, and by rotating the rotating member, the one end of the charging auxiliary member is wound around the rotating member or sent out from the rotating member, An image forming apparatus, wherein the auxiliary charging member is reciprocated in the developer transport direction of the developer carrying member. The image forming apparatus according to claim 1 .
An image forming apparatus comprising: a developer cartridge for storing a replenishment developer to be replenished in the developing device; and the charging auxiliary member and the developer cartridge are integrated.

Images