JP2005173012A - Developing apparatus, image forming apparatus and image forming system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the density reduction of a developer image on an image carrier. <P>SOLUTION: In the developing apparatus provided with a developing roller for carrying developer, an electrifying member in contact with the developing roller for negatively electrifying the developer, a supply roller for supplying the developer to the developing roller, a contact member coming in contact with the supply roller so that the supply roller may hold the developer, and for developing the latent image carried by the image carrier with the negatively electrified developer carried by the developing roller, the contact part coming in contact with the supply roller of the contact member is formed of metal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a developing device, an image forming apparatus, and an image forming system.

As the developing device, for example, a developing roller for carrying the developer, a charging member that contacts the developing roller and negatively charges the developer, and a supply roller for supplying the developer to the developing roller, , There is a developing device. The developing device develops the latent image carried on the image carrier using a negatively charged developer carried on the developing roller.
JP 2003-173081 A

Further, the developing device is provided with an abutting member that abuts on the supply roller in order to hold the developer on the supply roller. And conventionally, this contact part is often formed of resin.
However, when the contact portion of the contact member that contacts the supply roller is formed of resin, there is a problem that the density of the developer image on the image carrier is lowered.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a developing device capable of preventing a decrease in the density of a developer image on an image carrier, and such a developing device. An image forming apparatus and an image forming system are provided.

In order to solve the above-mentioned problems, the main present invention includes a developing roller for carrying a developer, a charging member for contacting the developing roller to negatively charge the developer, and a developer on the developing roller. A supply roller for supplying, and an abutting member for contacting the supply roller and holding the developer on the supply roller, and the negatively charged developer carried on the development roller In a developing device for developing a latent image carried on a carrier,
In the developing device, the contact portion of the contact member that contacts the supply roller is made of metal.

  Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

  According to the present invention, it is possible to provide a developing device capable of preventing a decrease in the density of a developer image on an image carrier, and to realize an image forming apparatus and an image forming system provided with such a developing device. It becomes possible.

  At least the following will be made clear by the description of the present specification and the accompanying drawings.

A developing roller for carrying the developer, a charging member that contacts the developing roller and negatively charges the developer, a supply roller for supplying the developer to the developing roller, and a contact with the supply roller And a contact member for holding the developer on the supply roller, and developing the latent image carried on the image carrier by a negatively charged developer carried on the development roller In
In the developing device, the contact portion of the contact member that contacts the supply roller is made of metal.
According to such a developing device, since the toner is negatively charged by the contact portion that is a metal, it is possible to prevent a decrease in the density of the developer image on the image carrier.

In the developing device, the developer may be negatively charged when contacting the contact portion, and the contact portion may hold the negatively charged developer on the supply roller.
According to such a developing device, since the developer is negatively charged when coming into contact with the contact portion, the charge amount of the developer is increased, and the density of the developer image on the image carrier is decreased. Can be more effectively prevented.

In the developing device, the supply roller is in contact with the development roller, and the supply roller is in contact with the supply roller and the development roller from a contact position between the contact member and the supply roller. The developer may be transported to a position, and the developing roller may transport the developer from a contact position between the supply roller and the development roller to a contact position between the development roller and the charging member. Good.
In the developing device having the above configuration, when the charge amount of the developer is small, the developer may not be sufficiently held on the supply roller or may not be sufficiently supported on the developing roller. is there. Therefore, when the supply roller or the development roller conveys the developer, the developer falls from the supply roller or the development roller due to the action of gravity or the like, and the conveyance amount of the developer by the supply roller or the development roller decreases. Sometimes. When the amount of developer transported by the supply roller and the developing roller decreases, the density of the developer image on the image carrier tends to decrease. Therefore, when the developer is negatively charged by the contact portion, the supply roller can securely hold the developer, and the development roller can reliably carry the developer. The conveyance amount can be prevented from decreasing, and the density of the developer image on the image carrier can be prevented from decreasing.

In the developing device, the contact position between the contact member and the supply roller is located below the contact position between the supply roller and the development roller, and the contact between the development roller and the charging member is low. The contact position may be located below the contact position between the supply roller and the developing roller, and a gap may be provided between the contact member and the charging member.
If there is a gap between the abutting member and the charging member, the developer around the gap may fall through the gap, which further reduces the density of the developer image on the image carrier. It becomes easy. Therefore, the effect of the present invention, that is, the effect that it is possible to more effectively prevent the decrease in the density of the developer image on the image carrier is more effectively exhibited.

In such a developing device, the developer may be non-magnetic.
When the developer is non-magnetic, the amount of developer transported by the supply roller and the developing roller may be smaller than when the developer is magnetic, and the developer image on the image carrier may be reduced. A decrease in the concentration of is more likely to occur. Therefore, the effects of the present invention and the effect that it is possible to prevent a decrease in the density of the developer image on the image carrier are more effectively exhibited.

In the developing device, the supply roller may be in contact with the development roller, and the rotation direction of the supply roller may be the same as the rotation direction of the development roller.
When the supply roller is in contact with the developing roller and the rotation direction of the supply roller is the same as the rotation direction of the developing roller, the developer held on the supply roller is supplied so as to be rubbed against the developing roller. In addition, since the developer is charged, the charge amount of the developer carried on the developing roller is increased. As a result, since the developer having an increased charge amount is reliably carried by the developing roller, it is possible to prevent a decrease in the transport amount of the developer by the developing roller.

In the developing device, the surface of the supply roller may be provided with an elastic portion that is made of urethane foam and holds the developer.
According to such a developing device, the supply roller holds the developer more reliably by the depression in the surface of the elastic portion formed of foamed urethane. As a result, it is possible to more effectively prevent a decrease in the amount of developer transported by the supply roller.

Further, in such a developing device, a housing portion for housing the developer, and a developer provided in the housing portion that rotates about a central axis, allows the developer housed in the housing portion to be brought into contact with the contact member. A conveying member for conveying, wherein the central axis of the conveying member is located below the central axis of the supply roller, and the abutting member is configured to receive the developer conveyed by the conveying member. The storing roller may supply the developer stored in the contact member to the developing roller.
When the central axis of the transport member is located below the central axis of the supply roller, the transport member is more sensitive than when the central axis of the transport member is positioned above the central axis of the supply roller. The developer that is transported and stored in the contact member tends to decrease. For this reason, the supply amount of the developer supplied to the developing roller by the supply roller may be insufficient, and the density of the developer image on the image carrier is likely to decrease. Therefore, the effect of the present invention, that is, the effect that it is possible to prevent the decrease in the density of the developer image on the image carrier is more effectively achieved.

In the developing device, the contact member may be a metal, and may be a member different from a member constituting the housing portion.
When the contact member is a metal and is a member different from the member constituting the housing portion, the contact member capable of preventing a decrease in the density of the developer image on the image carrier is provided. It can be easily manufactured.

Furthermore, a developing roller for carrying the developer, a charging member that contacts the developing roller and negatively charges the developer, a supply roller for supplying the developer to the developer roller, and the supply roller And a contact member for holding the developer on the supply roller, and the latent image carried on the image carrier is developed by the negatively charged developer carried on the development roller. In the developing device,
The contact portion of the contact member that contacts the supply roller is metal,
When the developer contacts the contact portion, the developer is negatively charged, and the contact portion holds the negatively charged developer on the supply roller,
The supply roller contacts the developing roller, and the supply roller conveys the developer from a contact position between the contact member and the supply roller to a contact position between the supply roller and the development roller. The developing roller conveys the developer from a contact position between the supply roller and the development roller to a contact position between the development roller and the charging member,
The contact position between the contact member and the supply roller is located below the contact position between the supply roller and the developing roller, and the contact position between the developing roller and the charging member is the supply roller. And a position below the contact position with the developing roller, a gap is provided between the contact member and the charging member,
The developer is non-magnetic,
The rotation direction of the supply roller is the same direction as the rotation direction of the developing roller,
The surface of the supply roller is formed of urethane foam and is provided with an elastic portion for holding the developer,
A storage portion for storing the developer, and a transport member provided in the storage portion for transporting the developer stored in the storage portion to the contact member by rotating about a central axis. The central axis of the conveying member is positioned below the central axis of the supply roller, the contact member stores the developer conveyed by the conveying member, and the supply roller Supplying the developer stored in the contact member to the developing roller;
It is also possible to realize a developing device in which the abutting member is a metal and is a member different from the member constituting the housing portion.

Furthermore, a developing roller for carrying the developer, a charging member that contacts the developing roller and negatively charges the developer, a supply roller for supplying the developer to the developer roller, and the supply roller And a contact member for holding the developer on the supply roller, and the latent image carried on the image carrier is developed by the negatively charged developer carried on the development roller. In an image forming apparatus comprising a developing device,
In the image forming apparatus, the contact portion of the contact member that contacts the supply roller is made of metal.
According to such an image forming apparatus, it is possible to realize an image forming apparatus superior to the conventional one by including a developing apparatus capable of preventing a decrease in the density of the developer image on the image carrier. It becomes.

Further, a computer main body, a developing roller connected to the computer main body for carrying the developer, a charging member for contacting the developing roller to negatively charge the developer, and a developer on the developing roller An abutting member for abutting the supply roller and holding the developer on the supply roller, and by a negatively charged developer carried on the developing roller, A developing device for developing a latent image carried on the image carrier;
In an image forming system comprising:
In the image forming system, the contact portion of the contact member that contacts the supply roller is made of metal.
According to such an image forming system, it is possible to realize an image forming system superior to the conventional one by including a developing device capable of preventing a decrease in the density of the developer image on the image carrier. It becomes.

=== Overview of Image Forming Apparatus (Laser Beam Printer) ===
An outline of a laser beam printer (hereinafter referred to as a printer) 1 as an example of an image forming apparatus will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view showing main components constituting the printer 1. In FIG. 1, the vertical direction is indicated by arrows. For example, the paper discharge tray 5 is disposed at the top of the printer 1, and the paper feed unit 50 is disposed at the bottom of the printer 1. .

<Example of Overall Configuration of Printer 1>
As shown in FIG. 1, the printer 1 according to the present embodiment includes a housing 3, a paper discharge tray 5 formed on the upper portion of the housing 3, and a door body 7 that can be opened and closed on the front surface of the housing. Have. Further, an image forming unit 20, a transfer belt unit 30, an exposure unit 10, and a paper feed unit 50 are provided in the housing 3, and a paper transport unit 60 is provided in the door body 7.

  The image forming unit 20 includes four image forming stations 21 in which four developing devices that store different color toners can be set. The four image forming stations 21 are for yellow, magenta, cyan, and black developing devices, and these are distinguished by reference numerals 21Y, 21M, 21C, and 21K in the drawing.

  Each image forming station 21Y (21M, 21C, 21K) is provided around a photosensitive drum 23Y (23M, 23C, 23K), which is an example of an image carrier, and a photosensitive drum 23Y (23M, 23C, 23K). A charging unit 25Y (25M, 25C, 25K) and a developing device 100Y (100M, 100C, 100K) are included. For example, the image forming station 21Y includes a photosensitive drum 23Y, a charging unit 25Y, and a developing device 100Y.

The photosensitive drum 23Y (23M, 23C, 23K) has a cylindrical conductive substrate and a photosensitive layer formed on the outer peripheral surface thereof, and is rotatable around a central axis. In the present embodiment, It rotates clockwise as indicated by the arrow in FIG.
The charging means 25Y (25M, 25C, 25K) is a device for charging the photosensitive drum 23Y (23M, 23C, 23K).
The developing device 100Y (100M, 100C, 100K) is a device for developing the latent image formed on the photosensitive drum 23Y (23M, 23C, 23K) using toner T, which is an example of a developer. Details of the developing device 100Y (100M, 100C, 100K) will be described later.

The transfer belt unit 30 includes an intermediate transfer belt 37, primary transfer rollers 43 </ b> Y, 43 </ b> M, 43 </ b> C, and 43 </ b> K, and a cleaning unit 41 that contacts the surface of the intermediate transfer belt 37. The transfer belt unit 30 includes a driving roller 31 that is rotationally driven by a driving source (not shown), a driven roller 33 that is provided obliquely above the driving roller 31, and a tension roller 35.
The drive roller 31 also serves as a backup roller for the secondary transfer roller 45. In addition, a rubber layer having a thickness of about 3 mm and a volume resistivity of 105 Ω · cm or less is formed on the peripheral surface of the drive roller 31, and the secondary transfer roller 45 is grounded through a metal shaft. The conductive path of the secondary transfer bias supplied via the first is constituted.
The driven roller 33 also functions as a backup roller for the cleaning means 41.

The tension roller 35 can control the tension of the intermediate transfer belt 37, the curvature of the arch, and the like by adjusting the position.
The intermediate transfer belt 37 is stretched between the driving roller 31, the driven roller 33, and the tension roller 35, and is driven to circulate in the direction X of the arrow in FIG.
The driven roller 33, the tension roller 35, and the intermediate transfer belt 37 are arranged side by side so as to incline with respect to the drive roller 31, so that when the intermediate transfer belt 37 is driven, the belt conveyance direction X is downward. The belt surface 37A is positioned on the lower side, and the belt surface 37B with the conveying direction facing upward is positioned on the upper side. The photosensitive drums 23Y, 23M, 23C, and 23K are in pressure contact with the belt surface 37A along the arched line.

In the exposure unit 10, a scanner unit 11 including a polygon mirror motor 11A and a polygon mirror 11B is vertically arranged on the bottom. In addition, a single f-θ lens 13 and a reflection mirror 15 are provided in the optical path B. Above the reflection mirror 15, the scanning optical paths of the respective colors are not parallel to the photosensitive drums 23Y, 23M, 23C, and 23K. A plurality of folding mirrors 17 are provided so as to be folded. The exposure unit 10 is provided in a space obliquely below the image forming unit 20.
In the exposure unit 10, an image signal corresponding to each color is emitted from the polygon mirror 11 </ b> B with a laser beam modulated and formed based on a common data clock frequency, and passes through the f-θ lens 13, the reflection mirror 15, and the folding mirror 17. The photosensitive drums 23Y, 23M, 23C, and 23K of the image forming stations 21Y, 21M, 21C, and 21K are irradiated to form latent images.

The paper feed unit 50 includes a paper feed cassette 51 in which the media P are stacked, and a pickup roller 53 that feeds the media P from the paper feed cassette 51 one by one. The paper feed unit 50 is provided below the exposure unit 10.
The paper transport unit 60 includes a gate roller pair 61 that defines the timing of feeding the medium P to the secondary transfer unit, a secondary transfer roller 45 that is pressed against the drive roller 31 and the intermediate transfer belt 37, and a fixing unit 63. , A paper discharge roller pair 65 and a duplex printing conveyance path 67.

  The fixing means 63 includes a rotatable fixing roller pair 63A having a heating element such as a halogen heater incorporated in at least one side, and at least one roller of the fixing roller pair 63A is pressed to the other side so as to be secondary to the sheet material. Pressing means for pressing the transferred secondary image against the medium P. The secondary image secondarily transferred to the medium P is fixed to the medium P at a predetermined temperature at the nip portion formed by the fixing roller pair 63A.

  As shown in FIG. 2, the control unit 80 includes a main controller 81 and a unit controller 83. An image signal is input to the main controller 81, and the unit controller 83 responds to a command based on the image signal. The unit is controlled to form an image.

<Operation of Printer 1>
Next, the operation of the printer 1 configured as described above will be described with reference to other components.
First, when an image signal and a control signal from a host computer (not shown) are input to the main controller 81 of the printer 1 via the interface (I / F) 85, the unit controller 83 based on a command from the main controller 81 The photosensitive drums 23Y, 23M, 23C, and 23K, the developing rollers 100Y, 100M, 100C, and 100K, which will be described later, and the intermediate transfer belt 37 are rotated by the control.

The photosensitive drums 23Y, 23M, 23C, and 23K are charged by the charging units 25Y, 25M, 25C, and 25K at the charging positions while rotating. The charged areas of the photosensitive drums 23Y, 23M, 23C, and 23K reach the exposure position as the photosensitive drums 23Y, 23M, 23C, and 23K rotate, and the exposure unit 10 performs yellow Y, magenta M, cyan C, and black. A latent image corresponding to K image information is formed in the area.
The latent images formed on the photosensitive drums 23Y, 23M, 23C, and 23K reach the developing position as the photosensitive drums 23Y, 23M, 23C, and 23K rotate, and are developed by the developing devices 100Y, 100M, 100C, and 100K. . As a result, toner images are formed on the photosensitive drums 23Y, 23M, 23C, and 23K.
The toner images formed on the photosensitive drums 23Y, 23M, 23C, and 23K reach the primary transfer position as the photosensitive drums 23Y, 23M, 23C, and 23K rotate, and are transferred by the primary transfer rollers 43Y, 43M, 43C, and 43K. The image is transferred to the intermediate transfer belt 37. At this time, a primary transfer voltage having a polarity opposite to the charging polarity of the toner T is applied to the primary transfer rollers 43Y, 43M, 43C, and 43K. As a result, the four color toner images formed on the respective photosensitive drums 23Y, 23M, 23C, and 23K are transferred to overlap the intermediate transfer belt 37, and a full color toner image is formed on the intermediate transfer belt 37. .

The full color toner image formed on the intermediate transfer belt 37 reaches the secondary transfer position as the intermediate transfer belt 37 rotates, and is transferred to the medium P by the secondary transfer roller 45. The medium P is conveyed from the paper feed cassette 51 to the secondary transfer roller 45 through the pickup roller 53 and the gate roller pair 61. When performing the transfer operation, the secondary transfer roller 45 is pressed against the intermediate transfer belt 37 and a secondary transfer voltage is applied.
The full-color toner image transferred to the medium P is heated and pressed by the fixing roller pair 63A and fused to the medium. On the other hand, the toner T remaining on the intermediate transfer belt 37 after the secondary transfer is scraped off by the cleaning blade 41A.
The medium on which the full-color toner image is fused is transported to the paper discharge tray 5 via the paper discharge roller pair 65 when double-sided printing is not performed, and is transported for double-sided printing when double-sided printing is performed. It is conveyed toward the path 67.

=== Overview of Control Unit ===
Next, the configuration of the control unit 80 will be described with reference to FIG. The main controller 81 of the control unit 80 is connected to a host computer via an interface 85 and includes an image memory 87 for storing an image signal input from the host computer.
The unit controller 83 is electrically connected to each unit (image forming unit 20, transfer belt unit 30, exposure unit 10, paper feed unit 50, paper transport unit 60) of the apparatus main body, and receives signals from sensors included in them. By receiving the signal, each unit is controlled based on a signal input from the main controller 81 while detecting the state of each unit.

=== Overview of Developing Device ===
Next, the outline of the developing device will be described with reference to FIG. FIG. 3 is a cross-sectional view showing main components of the developing device 100Y.
As in FIG. 1, FIG. 3 also shows the vertical direction in FIG. 3. For example, the central axis of the developing roller 140 is above the central axis of the photosensitive drum 23 </ b> Y.

<Example of overall configuration of developing device>
The developing device 100Y (100M, 100C, 100K) is set and used in each image forming station 21Y (21M, 21C, 21K). Since the configurations of the developing devices 100Y, 100M, 100C, and 100K are basically the same, the configuration of the developing device 100Y will be described with reference to FIG.

The developing device 100Y includes a housing 110. In the housing 110, a developing roller 140, a supply roller 130, a regulating blade 150 that is an example of a charging member, a seal member 160, a toner storage unit 120 that is an example of a storage unit, and an example of a transport member An agitator 170 and a toner guide member 180 which is an example of a contact member.
The developing roller 140 carries the toner T and conveys it to the developing position facing the photosensitive drum 23 in order to develop the latent image carried on the photosensitive drum 23Y with the toner T. The developing roller 140 is made of aluminum, stainless steel, iron, or the like, and is subjected to nickel plating, chrome plating, or the like, and sand blasting or the like on the toner carrying area as necessary.

The developing roller 140 is rotatable about the central axis, and rotates in a direction (counterclockwise in FIG. 3) opposite to the rotation direction of the photosensitive drum 23Y (clockwise in FIG. 3). The central axis is above the central axis of the photosensitive drum 23Y.
As shown in FIG. 3, there is a gap between the developing roller 140 and the photosensitive drum 23Y. That is, the developing device 100Y develops the latent image formed on the photosensitive drum 23Y in a non-contact state. The developing roller 140 is applied with a developing bias in which an AC voltage is superimposed on a DC voltage from a developing bias power source (not shown). Therefore, when developing the latent image formed on the photosensitive drum 23Y, an alternating electric field is formed between the developing roller 140 and the photosensitive drum 23Y.

  The supply roller 130 supplies the developing roller 140 with the toner T stored in a temporary storage unit 189 formed between a toner guide member 180 (described later) and the supply roller 130. The supply roller 130 has an elastic portion 130 </ b> B that holds the toner T and is formed of urethane foam around the core metal 130 </ b> A. On the surface of the elastic portion 130B, there are 70 to 100 cells (dents) per inch, and the toner T is held. Moreover, the elastic part 130B has conductivity, and its resistance value is 1.0 × 10 4 to 1.0 × 10 7 (Ω).

The supply roller 130 is in contact with the developing roller 140 in a state where the elastic portion 130B is elastically deformed. The amount of biting of the elastic portion 130B with respect to the developing roller is 0.5 mm.
The supply roller 130 is rotatable about the central axis, and rotates in the same direction (counterclockwise in FIG. 3) as the rotation direction of the developing roller 140 (counterclockwise in FIG. 3). As a result, the toner T is frictionally charged in the vicinity of the contact position H2 between the supply roller 130 and the developing roller 140. Further, the central axis of the supply roller 130 is above the central axis of the developing roller 140.
The supply roller 130 is applied with the same voltage as the developing bias voltage applied to the developing roller 140 from the developing bias power source described above.

  The regulating blade 150 regulates the layer thickness of the toner T carried on the developing roller 140 and gives a negative charge to the toner T carried on the developing roller 140. The regulating blade 150 includes a rubber part 151 that is abutted along the axial direction of the developing roller 140 and a support part 152 that supports the rubber part 151.

The rubber part 151 is made of silicon rubber, urethane rubber or the like, and the support part 152 has a function of urging the rubber part 151 toward the developing roller 140, so that it is a sheet-like thin plate having a spring property such as phosphor bronze or stainless steel. Is used. One end of the support portion 152 is fixed to the housing 110.
The end of the rubber portion 151 of the regulating blade 150 opposite to the side fixed to the housing 110, that is, the tip is not in contact with the developing roller 140, and a portion away from the tip by a predetermined distance is The developing roller 140 is in contact with the width. That is, the rubber part 151 of the regulating blade 150 is not in contact with the developing roller 140 at the edge, but is in contact with the belly.
Further, the regulating blade 150 is arranged so that the tip thereof faces the upstream side in the rotation direction of the developing roller 140, and is in a so-called counter contact. The contact position H3 between the regulating blade 150 and the developing roller 140 is below the contact position H2 between the supply roller and the developing roller, and below the central axis of the developing roller 140.
Further, an elastic member 153 is provided on the side of the regulating blade 150 opposite to the developing roller 140 side. Due to the action of the support portion 152 and the elastic member 153, the rubber portion 151 is always pressed uniformly in the longitudinal direction of the developing roller 140, and an excess portion of the toner T adhering to the peripheral surface of the developing roller 140 is scraped off. As a result, a certain amount of toner T is carried on the peripheral surface of the developing roller 140. The toner T thus scraped off naturally falls and is mixed into the toner T in the toner storage unit 120.

  The seal member 160 has one end fixed to the housing 110 and the other end in contact with the developing roller 140. The seal member 160 collects the toner T on the developing roller 140 that has passed through the developing position without being scraped off, and prevents the toner T in the developing device 100Y from leaking out of the device. The seal member 160 is a member made of a polyethylene film or the like. The contact position at which the seal member 160 contacts the developing roller 140 is above the central axis of the developing roller 140.

The toner storage unit 120 stores toner T for developing the latent image carried on the photosensitive drum 23Y. As shown in FIG. 3, the toner storage unit 120 is formed in a cylindrical shape. In addition, the toner storage unit 120 forms a part of the housing 110 and is formed of resin or the like.
An agitator 170 is provided in the toner storage unit 120. The agitator 170 includes two arm members 173 that extend in opposite directions around a central axis 171, and each arm member 173 is set to a dimension that is slightly shorter than the diameter of a circle in the cross section of the toner storage unit 120.

From the tip of each arm member 173, a stirring fin 175 extends in the opposite direction (counterclockwise in FIG. 3) to the rotational direction of the agitator 170 (clockwise in FIG. 3). The stirring fin 175 is made of a flexible member, and the tip side thereof is in pressure contact with the inner peripheral surface of the cylindrical toner container 120 by an elastic force resulting from the flexibility.
Further, the agitator 170 rotates around the central shaft 171 in the direction (clockwise in FIG. 3) opposite to the rotation direction of the supply roller 130 (counterclockwise in FIG. 3). The central axis is below the central axis of the supply roller 130 and below the central axis of the developing roller 140.

  When the agitator 170 having such a configuration rotates, the toner T present in the region 177 between the inner peripheral surface of the toner storage unit 120 and the stirring fin 175 is scraped up by the stirring fin 175 so as to be described later. It can be conveyed onto the member 180. Further, the agitator 170 has a function of stirring the toner T stored in the toner storage unit 120 by rotating about the central shaft 171.

Note that the toner T described above is non-magnetic. Therefore, unlike magnetic toner, the toner is not held on the supply roller 130 or the like by magnetic force. In addition, non-magnetic toner is less easily charged than magnetic toner.
The toner T is a polymerization toner having a good circularity.

<Configuration of toner guide member>
The toner guide member 180 stores the toner T conveyed by the stirring fin 175, and holds the stored toner T on the supply roller 130 that is in contact therewith. The toner guide member 180 includes a scraper 181, a flat conveyance unit 183, a bending unit 184, and a contact unit 185.

The scraper 181 is provided at an end portion on the side away from the supply roller 130, and is formed at an acute angle to scrape off the toner T conveyed by the stirring fin 175. The flat conveying unit 183 is formed in a planar manner with the upper surface side inclined more than the repose angle of the toner T on the supply roller 130 side than the scraper 181.
The curved portion 184 is formed on the downstream side of the flat conveyance portion 183. Further, a primary storage portion 189 of the toner T whose cross section narrows in a wedge shape is formed between the curved portion 184 and the peripheral surface of the supply roller 130. Here, the wedge-shaped cross section means that the entrance side is relatively large and becomes narrower in the traveling direction of the toner T.
The contact portion 185 is in contact with the peripheral surface of the elastic portion 130 </ b> B of the supply roller 130 on the downstream side of the curved portion 184. The amount of biting into the contact portion 185 of the elastic portion 130B is 0.2 mm, and the biting width is 3.5 mm.
The contact position H1 between the toner guide member 180 and the supply roller 130 is located below the contact position H2 between the supply roller 130 and the developing roller 140. Further, a gap A is provided between the toner guide member 180 and the regulating blade 150. The toner T scraped off from the developing roller 140 by the rubber part 151 passes through the gap A and is returned to the toner containing part 120.

In the toner guide member 180 having such a shape, after the toner T conveyed by the stirring fin 175 is scraped off by the scraper 181, the toner T extends along the flat conveying portion 183 in the width direction thereof and the inclination thereof. Gravity drops at a uniform speed at any point in the direction, and are temporarily stored in the toner temporary storage unit 189.
In the temporary toner storage portion 189 that narrows in a wedge shape, as the toner T advances to a narrow region, the pressure contact force against the peripheral surface of the supply roller 130 gradually increases, and therefore the toner T is applied to the peripheral surface of the supply roller 130. Is pressed, and the toner T is easily held on the peripheral surface. When the toner T is pushed out beyond the contact portion 185, the toner T passes through the gap A and falls into the toner guide space portion 192 and is guided directly or to the toner guide surface 190. The toner is returned to the toner container 120.

The toner guide member 180 is made of metal. As the metal, for example, aluminum, SECC (galvanized steel plate), SPCC (cold rolled steel plate) + nickel plating, or the like is used. When the toner T comes into contact with the contact portion 185, the toner T is negatively charged.
Further, the toner guide member 180 is a member different from the members constituting the toner storage unit 120. Therefore, it is possible to form the toner accommodating portion 120 with resin and the toner guide member 180 with metal. Further, the contact portion 185 that is in contact with the elastic portion 130B of the supply roller 130 is grounded.

<Operation of developing device>
In the developing device 100 </ b> Y configured as described above, as the agitator 170 rotates, the agitation fins 175 transport the toner T onto the toner guide member 180 so as to scoop up the toner T present in the region 177.
The toner T conveyed onto the toner guide member 180 by the stirring fin 175 is temporarily stored in the temporary storage unit 189. The toner T stored in the temporary storage unit 189 is negatively charged when coming into contact with the elastic part 130B or the contact part 185. The negatively charged toner T is held on the supply roller 130 by the contact portion 185.

  The toner T held on the supply roller 130 is conveyed by the rotation of the supply roller 130 from the contact position H1 between the toner guide member 180 and the supply roller 130 to the contact position H2 between the supply roller 130 and the developing roller 140. Is done. Then, in the vicinity of the contact position H2, the toner T moves from the supply roller 130 to the developing roller 140, and the developing roller 140 carries the toner T. The toner T carried on the developing roller 140 is transported from the contact position H2 between the supply roller 130 and the development roller 140 to the contact position H3 between the development roller 140 and the regulating blade 150 by the rotation of the development roller 140. Is done.

  When the toner T that has reached the contact position H3 by the rotation of the developing roller 140 passes through the contact position H3, a negative charge is applied to the toner T by the restriction blade 150 and the layer thickness is restricted. The negatively charged toner T on the developing roller 140 whose layer thickness is regulated reaches the developing position facing the photosensitive drum 23Y by further rotation of the developing roller 140, and on the photosensitive drum 23Y under an alternating electric field at the developing position. The latent image formed in (1) is subjected to development.

On the other hand, the toner T scraped off by the regulating blade 150 passes through the gap A and falls into the toner guide space portion 192 and is guided directly or by the toner guide surface 190 and returned to the toner storage portion 120.
Further, by further rotation of the developing roller 140, the toner T on the developing roller 140 that has passed the developing position passes through the seal member 160 and is collected in the developing device 100Y without being scraped off.

=== About work function ===
The work function (Φ) of a substance is known as the energy required to extract electrons from the substance. The smaller the work function, the easier it is to emit electrons, and the larger the work function, the harder it is to emit electrons. Therefore, when a substance having a small work function is brought into contact with a substance having a small work function, the substance having a small work function is positively charged, and the substance having a large work function is negatively charged.

The work function is measured by the following measurement method, and is quantified as energy (eV) for extracting electrons from the material. The work function includes a toner composed of various materials and various members in the image forming apparatus. The chargeability by contact can be evaluated.
The work function (Φ) is measured using a surface analyzer (AC-2, low energy electronic counting method manufactured by Riken Keiki Co., Ltd.). In the present invention, in the apparatus, a deuterium lamp is used, the irradiation light quantity is set to 500 nW, monochromatic light is selected by a spectroscope, the irradiation area is set to 4 mm square, and the energy scanning range is 3.4 to 6. The sample is irradiated at 2 eV and at a measurement time of 10 sec / 1 place. It is obtained by detecting photoelectrons emitted from the sample surface, and the work function is measured with a repeatability (standard deviation) of 0.02 eV. In addition, as a measurement environment for ensuring data reproducibility, a 24-hour standing product is used as a measurement sample under the conditions of operating temperature and humidity of 25 ° C. and 55% RH.

  The work function of the toner T measured by the surface analyzer is 5.48 eV for yellow toner, 5.52 eV for magenta toner, 5.35 eV for cyan toner, and 5.46 eV for black toner.

  The work function of the contact portion 185 of the toner guide member 180 made of aluminum is 4.9 eV. This value is smaller than the work function of the above four color toners. Note that the work function of a metal other than aluminum (for example, SECC, SPCC + nickel plating, etc.) is also smaller than that of the toner T. Therefore, when the toner T comes into contact with the contact portion 185 made of metal, the electrons move from the contact portion 185 to the toner T, so that the toner T is negatively charged.

  The work function of the elastic portion 130B is 5.1 to 5.2. This value is smaller than the work function of the above four color toners. Therefore, when the toner T comes into contact with the elastic portion 130B, electrons move from the elastic portion 130B to the toner T, so that the toner T is negatively charged.

=== About the function of the contact member ===
As described above, the toner guide member 180 is a metal such as aluminum. As a result, it is possible to prevent a decrease in the density of the toner images on the photosensitive drums 23Y, 23M, 23C, and 23K. This will be described in detail below.

  The effect when the toner guide member 180 is metal will be described with reference to FIGS. 4A and 4B. FIG. 4A is a view showing a toner guide member 380 for comparison. FIG. 4B is a schematic diagram when the comparative toner guide member 380 is viewed from the X direction in FIG. 4A.

  The comparative toner guide member 380 shown in FIGS. 4A and 4B is different from the toner guide member 180 according to the present embodiment. That is, as shown in FIG. 4B, the comparative toner guide member 380 shown in FIG. 4A is formed of one side half of aluminum (380A in FIG. 4B) and the other half of ABS (acrylonitrile-butadiene-styrene) resin. (380B in FIG. 4B). The reason why the contact portion is formed of ABS resin is that the contact portion is conventionally formed of ABS resin in many cases.

On the other hand, in terms of shape and the like, the toner guide member 180 and the toner guide member 380 for comparison are the same.
In the developing device provided with such a toner guide member 380, a medium on which an image formed with the same density (hereinafter also referred to as “solid image”) is formed on almost the entire medium is the medium shown in FIG. is there. A region P1 in FIG. 5 indicates an image region formed using the toner T held on the supply roller 130 by the toner guide member 380A formed of aluminum. A region P2 in FIG. 5 indicates an image region formed using the toner T held on the supply roller 130 by the toner guide member 380B formed of ABS resin.

  Then, the density of the image on the medium P is measured using a color reflection densitometer X-Rite 404. The positions at which the image density is measured are the front end side and the rear end side with respect to the medium conveyance direction shown in FIG. That is, the image density of the image front end portion (F1 in FIG. 5) and the image rear end portion (R1 in FIG. 5) on the region P1 is measured, and the image front end portion (in FIG. 5 in FIG. 5) is measured. F2) and the image density of the rear end portion of the image (R2 in FIG. 5) are measured.

As a result of the measurement, the density value of the image at F1 is 1.38, whereas the density value of the image at R1 is 1.35. On the other hand, the density value of the image at F2 is 1.38, whereas the density value of the image at R2 is 1.22. The difference in image density between the image leading end side and the image trailing end side is smaller in the P1 image than in the P2 image.
That is, when the toner guide member is made of resin, the image density of the rear end portion of the image is lower than the front end portion of the image. On the other hand, when the toner guide member is made of metal, the image density of the rear end portion of the image is hardly lowered with respect to the front end portion of the image.
The image density at the rear end portion of the image is lower than the image density at the image front end portion of the medium. The density of toner images on the photosensitive drums 23Y, 23M, 23C, and 23K (hereinafter also referred to as “rear end toner image”) corresponding to the rear end portion of the image is higher than the density of “front end toner image”). It is because it has fallen.
The density of the trailing edge toner image decreases with respect to the density of the leading toner image. The supply amount of the toner T to the developing roller 140 by the supply roller 130 corresponds to the consumption amount of the toner T by the developing roller 140. This is because there is a shortage.

By the way, since the work function of the metal is smaller than that of the resin, the metal contact portion 185 is easier to negatively charge the toner than the resin contact portion.
Further, since the supply roller 130 holds the toner and the development roller 140 carries the toner and conveys the toner, the toner is surely held by the supply roller 130 or the toner is surely supplied to the development roller 140. If the toner is not carried on the toner, the amount of toner transported by the supply roller 130 and the developing roller 140 may decrease.

On the other hand, when the toner is charged, the charged toner is securely held by the supply roller 130 and is reliably carried by the developing roller 140. Therefore, the amount of toner transported by the supply roller 130 and the developing roller 140 is reduced. The decrease is unlikely to occur, and the shortage of the supply amount of the toner T to the developing roller 140 by the supply roller 130 can be solved.
Therefore, the toner guide member 180 is made of metal, so that the shortage of toner transport by the supply roller 130 and the developing roller 140 can be solved, and the density of the trailing edge toner image is prevented from lowering with respect to the density of the leading edge toner image. Is possible. This coincides with the density result of the image formed using the toner guide member 380 described above.

As described above, when the toner guide member 180 formed of a metal such as aluminum is used, it is possible to prevent the density of toner images on the photosensitive drums 23Y, 23M, 23C, and 23K from being lowered.
Further, the contact portion 185 causes the toner T to be negatively charged (hereinafter also referred to as “pre-charge”) before being negatively charged by the regulating blade 150. As a result, the toner T precharged by the contact portion 185 is further negatively charged by the regulating blade 150, and therefore the negative charge amount of the toner T used for developing the latent images on the photosensitive drums 23Y, 23M, 23C, and 23K. Can be increased.

=== Other Embodiments ===
The image forming apparatus and the like according to the present invention have been described above based on the above embodiment. However, the above embodiment of the present invention is for facilitating understanding of the present invention and limits the present invention. is not. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes the equivalents thereof.

  The present invention relates to a developing roller (for example, developing roller 140) for carrying a developer (for example, toner T), and a charging member (for example, a regulating blade) for contacting the developing roller and negatively charging the developer. 150), a supply roller (for example, supply roller 130) for supplying developer to the developing roller, and a contact member (for example, for holding the developer on the supply roller by contacting the supply roller) A latent image carried on an image carrier (for example, photosensitive drums 23Y, 23M, 23C, and 23K) by a negatively charged developer carried on the developing roller. In a developing device (for example, developing devices 100Y, 100M, 100C, and 100K), a contact portion (for example, contact portion 185) of the contact member that contacts the supply roller. Relates a developing device which is a metal.

  In the above embodiment, an intermediate transfer type full color laser beam printer has been described as an example of the image forming apparatus. However, the present invention is not limited to the intermediate transfer type, but a full color laser beam printer, a monochrome laser beam printer, a copying machine, The present invention can be applied to various image forming apparatuses such as facsimiles.

  In the above-described embodiment, the image forming apparatus including the tandem developing devices 100Y, 100M, 100C, and 100K has been described as an example. However, the present invention is not limited to this. For example, the present invention can be applied to an image forming apparatus provided with a rotary developing device.

  In the above-described embodiment, the image carrier is described as a configuration in which a photosensitive layer is provided on the outer peripheral surface of a cylindrical conductive substrate. However, the present invention is not limited to this. For example, a so-called photosensitive belt configured by providing a photosensitive layer on the surface of a belt-like conductive substrate may be used.

  In the above-described embodiment, the toner is described as being a polymerization toner, but is not limited thereto. For example, the toner may be a pulverized toner. However, since the circularity of the polymerization toner is better, charging of the toner is advantageous.

In the embodiment described above, the regulation blade 150 having the rubber part 151 is brought into contact with the developing roller 140 formed of aluminum or the like. However, the present invention is not limited to this.
For example, as shown in FIG. 6, a regulating blade 250 made of SUS (stainless steel) may be brought into contact with the developing roller 240 whose surface is made of rubber 240B. FIG. 6 is a diagram for explaining another embodiment of the developing roller and the charging member.

  In the above embodiment, the supply roller 130 contacts the developing roller 140, and the supply roller 130 starts from the contact position H 1 (see FIG. 3) between the toner guide member 180 and the supply roller 130. The developing roller 140 transports the toner T to the contact position H2 (see FIG. 3) between the developing roller 140 and the developing roller 140. The developing roller 140 starts from the contact position H2 between the supply roller 130 and the developing roller 140, and the developing roller 140 and the regulating blade 150 The toner T is conveyed to the contact position H3 (see FIG. 3), but is not limited thereto.

  However, if the supply roller 130 transports the toner T from the contact position H1 to the contact position H2, and the developing roller 140 transports the toner T from the contact position H2 to the contact position H3, the toner When the charge amount of T is small, the toner T may not be sufficiently held on the supply roller 130 or may not be sufficiently carried on the developing roller 140. Therefore, when the supply roller 130 or the developing roller 140 conveys the toner T, the toner T falls from the supply roller 130 or the developing roller 140 due to the action of gravity or the like. The transport amount may decrease. When the transport amount of the toner T by the supply roller 130 and the developing roller 140 decreases, the density of the toner images on the photosensitive drums 23Y, 23M, 23C, and 23K is likely to decrease.

  Therefore, when the toner T is negatively charged by the contact portion 185, the supply roller 130 can reliably hold the toner T, and the developing roller 140 can reliably carry the toner T. Therefore, the supply roller 130 and the developing roller The amount of toner T transported by 140 can be prevented from decreasing, and the density of toner images on the photosensitive drums 23Y, 23M, 23C, and 23K can be prevented from decreasing.

  In the above embodiment, the contact position H1 between the toner guide member 180 and the supply roller 130 is located below the contact position H2 between the supply roller 130 and the developing roller 140, and the developing roller 140 and the regulating blade 150 is located below the contact position H2 between the supply roller 130 and the developing roller 140, and a gap A (see FIG. 3) is provided between the toner guide member 180 and the regulating blade 150. However, the present invention is not limited to this.

For example, no gap may be provided between the toner guide member 180 and the regulating blade 150.
If there is a gap A between the toner guide member 180 and the regulating blade 150, the toner T around the gap A may fall through the gap A, and the toner T on the photosensitive drums 23Y, 23M, 23C, and 23K. The toner image density is more likely to decrease. Therefore, the effect of the present invention, that is, the effect that it is possible to more effectively prevent the decrease in the density of the toner image on the photosensitive drums 23Y, 23M, 23C, and 23K is more effectively achieved.
Therefore, the above embodiment is more desirable.

In the above embodiment, the toner T is non-magnetic. However, the present invention is not limited to this.
For example, the toner may have magnetism.
When the toner T is non-magnetic, the amount conveyed by the supply roller 130 and the developing roller 140 may be smaller than when the toner has magnetism, and the toner on the photosensitive drums 23Y, 23M, 23C, and 23K may be smaller. The image density is more likely to decrease. Therefore, the effects of the present invention and the effect that it is possible to prevent the density of the toner images on the photosensitive drums 23Y, 23M, 23C, and 23K from being lowered can be more effectively achieved.
Therefore, the above embodiment is more desirable.

In the above embodiment, the supply roller 130 contacts the developing roller 140 and the rotation direction of the supply roller 130 is the same as the rotation direction of the developing roller 140. However, the present invention is not limited to this. It is not a thing.
For example, the supply roller 130 may not be in contact with the developing roller 140. Further, the rotation direction of the supply roller 130 may be different from the rotation direction of the developing roller 140.
However, when the supply roller 130 contacts the developing roller 140 and the rotation direction of the supply roller 130 is the same as the rotation direction of the developing roller 140, the toner T held on the supply roller 130 is transferred to the developing roller 140. Since the toner T is charged when supplied so as to be rubbed, the charge amount of the toner T carried on the developing roller 140 increases. As a result, the toner T having an increased charge amount is reliably carried by the developing roller 140, and thus it is possible to prevent a decrease in the transport amount of the toner T by the developing roller 140.
Therefore, the above embodiment is more desirable.

Further, in the above-described embodiment, the surface of the supply roller 130 is provided with the elastic portion 130B that is formed of urethane foam and holds the toner T. However, the present invention is not limited to this. is not.
For example, the elastic part may be formed of a member other than urethane foam.
However, when the elastic portion 130B is formed of urethane foam, the supply roller 130 holds the toner T more reliably by the cells on the surface of the elastic portion 130B formed of urethane foam. As a result, it is possible to more effectively prevent a decrease in the transport amount of the toner T by the supply roller 130.
Therefore, the above embodiment is more desirable.

In the above embodiment, the toner storage unit 120 for storing the toner T and the toner stored in the toner storage unit 120 are provided in the toner storage unit 120 and rotated about the central axis. An agitator 170 for conveying T to the toner guide member 180, the central axis of the agitator 170 being positioned below the central axis of the supply roller 130, and the toner guide member 180 is conveyed by the agitator 170. The supplied toner T is stored, and the supply roller 130 supplies the toner T stored in the toner guide member 180 to the developing roller 140. However, the present invention is not limited to this.
For example, the central axis of the agitator may be located above the central axis of the supply roller.
However, when the central axis of the agitator 170 is located below the central axis of the supply roller 130, compared to the case where the central axis of the agitator 170 is located above the central axis of the supply roller 130. Therefore, the amount of toner conveyed by the agitator 170 and stored in the temporary storage unit 189 tends to decrease. For this reason, the supply amount of the toner supplied to the developing roller 140 by the supply roller 130 may be insufficient, and the density of the toner images on the photosensitive drums 23Y, 23M, 23C, and 23K is likely to decrease. Therefore, the effect of the present invention, that is, the effect that it is possible to more effectively prevent the decrease in the density of the toner image on the photosensitive drums 23Y, 23M, 23C, and 23K is more effectively achieved.
Therefore, the above embodiment is more desirable.

In the above embodiment, the toner guide member 180 is made of metal and is a member different from the member constituting the toner storage unit 120. However, the present invention is not limited to this.
For example, in the toner guide member, only the contact portion 185 may be made of metal, and other portions (the scraper 181, the flat conveyance portion 183, and the curved portion 184) may be made of resin or the like. Further, the toner guide member may be a member integrated with a member constituting the toner storage portion.
However, when the toner guide member 180 is a metal and is a member different from the member constituting the toner storage unit 120, the toner image density on the photosensitive drums 23Y, 23M, 23C, and 23K is prevented from being lowered. The toner guide member 180 that can be manufactured can be easily manufactured.
Therefore, the above embodiment is more desirable.

=== Configuration of Image Forming System etc. ===
Next, an image forming system according to an embodiment of the present invention will be described with reference to FIGS. 7 and 8. FIG.

  FIG. 7 is an explanatory diagram showing an external configuration of the image forming system. The image forming system 700 includes a computer 702, which is an example of a computer main body, a display device 704, a printer 1, an input device 708, and a reading device 710.

  In this embodiment, the computer 702 is housed in a mini-tower type housing, but is not limited thereto. The display device 704 is generally a CRT (Cathode Ray Tube), a plasma display, a liquid crystal display device, or the like, but is not limited thereto. As the printer 1, the printer described above is used. In this embodiment, the input device 708 uses a keyboard 708A and a mouse 708B, but is not limited thereto. In this embodiment, the reading device 710 uses a flexible disk drive device 710A and a CD-ROM drive device 710B. However, the reading device 710 is not limited to this. For example, an MO (Magneto Optical) disk drive device or a DVD (Digital Versatile) is used. Disk) etc. may be used.

  FIG. 8 is a block diagram showing a configuration of the image forming system shown in FIG. An internal memory 802 such as a RAM and an external memory such as a hard disk drive unit 804 are further provided in a housing in which the computer 702 is housed.

  In the above description, the example in which the printer 1 is connected to the computer 702, the display device 704, the input device 708, and the reading device 710 to configure the image forming system has been described. However, the present invention is not limited to this. Absent. For example, the image forming system may include the computer 702 and the printer 1, and the image forming system may not include any of the display device 704, the input device 708, and the reading device 710.

  For example, the printer 1 may have a part of each function or mechanism of the computer 702, the display device 704, the input device 708, and the reading device 710. As an example, the printer 1 includes an image processing unit that performs image processing, a display unit that performs various displays, a recording medium attachment / detachment unit for attaching / detaching a recording medium that records image data captured by a digital camera or the like. It is good also as a structure to have.

  The image forming system realized in this way is a system superior to the conventional system as a whole system.

2 is a schematic cross-sectional view showing main components constituting the printer 1. FIG. 2 is a block diagram showing a control unit 80 of the printer 1. FIG. It is sectional drawing which showed the main components of the developing device 100Y. FIG. 4A is a view showing a toner guide member 380 for comparison. FIG. 4B is a schematic diagram when the comparative toner guide member 380 is viewed from the X direction in FIG. 4A. It is the figure which showed the medium in which the solid image was formed. It is a figure for demonstrating another Example of a developing roller and a charging member. 1 is a diagram illustrating an external configuration of an image forming system 700. FIG. It is a block which shows the structure of the image forming system 700 shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer 3 Housing 5 Paper discharge tray 7 Door body 10 Exposure unit 11 Scanner part 11A Polygon mirror motor 11B Polygon mirror 13 f-theta lens 15 Reflecting mirror 17 Folding mirror 20 Image forming unit 21 Image forming station 23 Photosensitive drum 25 Charging means 30 Transfer belt unit 31 Drive roller 33 Drive roller 35 Tension roller 37 Intermediate transfer belt 37A Belt surface 37B Belt surface 41 Cleaning means 41A Cleaning blade 41B Toner transport path 43 Primary transfer roller 45 Secondary transfer roller 50 Paper feed unit 51 Paper feed cassette 53 Pickup roller 60 Paper transport unit 61 Gate roller pair 63 Fixing means 63A Fixing roller pair 65 Paper discharge roller pair 67 Double-sided print transport path 80 Control unit 81 main controller 83 unit controller 85 interface 87 image memory 89 CPU
DESCRIPTION OF SYMBOLS 100 Developing device 110 Housing 120 Toner accommodating part 130 Supply roller 130A Core metal 130B Elastic part 140 Developing roller 150 Restricting blade 151 Contact part 152 Support part 153 Elastic member 160 Seal member 170 Agitator 171 Rotating shaft 173 Arm member 175 Stirring fin 177 region 180 Toner guide member 181 Scraper 183 Flat conveyance unit 184 Curved portion 185 Contact portion 189 Temporary storage portion 190 Toner guide surface 192 Toner guide space portion 700 Image forming system 702 Computer 704 Display device 708 Input device 708A Keyboard 708B Mouse 710 Reading device 710A Flexible disk drive device 710B CD-ROM drive device 802 Internal memory 804 Hard disk drive unit Tsu DOO H1 toner guide member and the contact position A gap between the contact position H2 feed roller the feed roller and the contact position H3 developing roller of the developing roller and the restriction blade
P Medium T Toner

Claims (12)

A developing roller for carrying the developer;
A charging member that contacts the developing roller and negatively charges the developer;
A supply roller for supplying developer to the developing roller;
An abutting member that abuts on the supply roller and holds the developer on the supply roller;
In the developing device for developing the latent image carried on the image carrier by the negatively charged developer carried on the developing roller,
The developing device according to claim 1, wherein a contact portion of the contact member that contacts the supply roller is a metal. The developing device according to claim 1,
When the developer comes into contact with the contact portion, it is negatively charged,
The developing device according to claim 1, wherein the contact portion holds the negatively charged developer on the supply roller. The developing device according to claim 1 or 2,
The supply roller is in contact with the developing roller;
The supply roller conveys developer from a contact position between the contact member and the supply roller to a contact position between the supply roller and the development roller;
The developing device transports a developer from a contact position between the supply roller and the development roller to a contact position between the development roller and the charging member. The developing device according to claim 3,
The contact position between the contact member and the supply roller is located below the contact position between the supply roller and the developing roller,
The contact position between the developing roller and the charging member is located below the contact position between the supply roller and the developing roller,
A developing device, wherein a gap is provided between the contact member and the charging member. In the developing device according to claim 3 or 4,
The developing device, wherein the developer is non-magnetic. In the developing device according to any one of claims 1 to 5,
The supply roller is in contact with the developing roller;
The developing device according to claim 1, wherein a rotation direction of the supply roller is the same as a rotation direction of the developing roller. In the developing device according to any one of claims 1 to 6,
A developing device, wherein a surface of the supply roller is provided with an elastic portion formed of urethane foam for holding a developer. In the developing device according to any one of claims 1 to 7,
An accommodating portion for accommodating the developer;
A conveying member provided in the accommodating portion and configured to rotate around a central axis to convey the developer accommodated in the accommodating portion to the contact member;
The central axis of the conveying member is located below the central axis of the supply roller,
The contact member stores the developer transported by the transport member,
The developing device, wherein the supply roller supplies the developer stored in the contact member to the developing roller. The developing device according to claim 8, wherein
The developing device according to claim 1, wherein the contact member is made of metal and is a member different from a member constituting the housing portion. A developing roller for carrying the developer, a charging member that contacts the developing roller and negatively charges the developer, a supply roller for supplying the developer to the developing roller, and a contact with the supply roller And a contact member for holding the developer on the supply roller, and developing the latent image carried on the image carrier by a negatively charged developer carried on the development roller In
The contact portion of the contact member that contacts the supply roller is metal,
When the developer contacts the contact portion, the developer is negatively charged, and the contact portion holds the negatively charged developer on the supply roller,
The supply roller contacts the developing roller, and the supply roller conveys the developer from a contact position between the contact member and the supply roller to a contact position between the supply roller and the development roller. The developing roller conveys the developer from a contact position between the supply roller and the development roller to a contact position between the development roller and the charging member,
The contact position between the contact member and the supply roller is located below the contact position between the supply roller and the developing roller, and the contact position between the developing roller and the charging member is the supply roller. And a position below the contact position with the developing roller, a gap is provided between the contact member and the charging member,
The developer is non-magnetic,
The rotation direction of the supply roller is the same direction as the rotation direction of the developing roller,
The surface of the supply roller is formed of urethane foam and is provided with an elastic portion for holding the developer,
A storage portion for storing the developer, and a transport member provided in the storage portion for transporting the developer stored in the storage portion to the contact member by rotating about a central axis. The central axis of the conveying member is positioned below the central axis of the supply roller, the contact member stores the developer conveyed by the conveying member, and the supply roller Supplying the developer stored in the contact member to the developing roller;
The developing device according to claim 1, wherein the contact member is made of metal and is a member different from a member constituting the housing portion. A developing roller for carrying the developer, a charging member that contacts the developing roller and negatively charges the developer, a supply roller for supplying the developer to the developing roller, and a contact with the supply roller And a contact member for holding the developer on the supply roller, and developing the latent image carried on the image carrier by a negatively charged developer carried on the development roller ,
In an image forming apparatus comprising:
An image forming apparatus, wherein a contact portion of the contact member that contacts the supply roller is made of metal. A computer body, and
A developing roller connected to the computer main body for carrying the developer, a charging member that contacts the developing roller and negatively charges the developer, and a supply roller for supplying the developer to the developing roller And an abutting member that abuts the supply roller and holds the developer on the supply roller, and is carried on the image carrier by the negatively charged developer carried on the development roller. A developing device for developing a latent image,
In an image forming system comprising:
An image forming system, wherein a contact portion of the contact member that contacts the supply roller is made of metal.

Images