JP2014044294A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress adhesion of toner to an image carrier in an image forming apparatus that removes a toner remaining on an image carrier by using a cleaning blade.SOLUTION: The image forming apparatus includes a cleaning blade 13 that removes a toner remaining on a photoreceptor 2 by pressing a tip ridge part on the photoreceptor, and is provided with auxiliary cleaning means 16 arranged on the downstream side of the cleaning blade for coming into contact with the toner adhered on the photoreceptor to reduce adhesion force of the toner to the photoreceptor.

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer.

  In the image forming apparatus, the toner remaining on the image carrier without being transferred onto the transfer medium is removed by a cleaning device. As a cleaning device, it is known to use a strip-shaped cleaning blade made of an elastic body such as polyurethane rubber because it has a simple configuration and excellent cleaning performance (for example, Patent Document 1). The cleaning blade presses the tip ridge line portion (hereinafter referred to as an edge portion) against the peripheral surface of the image carrier, and clogs and removes the toner remaining on the image carrier.

  In recent years, a technique using a low-melting-point toner containing crystalline polyester capable of energy-saving fixing is known in order to meet the demand for energy saving in image forming apparatuses (for example, Patent Documents 2 and 3).

  However, when the low-melting-point toner is removed from the image carrier using the cleaning blade, there is a problem that the toner adheres to the image carrier easily. This is considered to be due to the following reasons.

  Since the cleaning blade presses the edge portion against the peripheral surface of the image carrier, a large frictional force is generated between the edge portion and the image carrier. For this reason, the edge part of a cleaning blade may vibrate abnormally, and abnormal noise (squeal) or abnormal vibration (chatter) may occur. Further, there is a possibility that a so-called blade curl that reverses the edge portion so as to follow the rotation direction of the image carrier or damage to the edge portion of the cleaning blade or the surface of the image carrier. However, in practice, not all of the remaining toner on the image carrier is scraped off, and a very small amount of toner remains on the edge portion of the cleaning blade. The remaining toner acts as a lubricant between the cleaning blade and the image carrier, preventing problems such as abnormal noise, abnormal vibration, curling and breakage.

  A very small amount of toner remaining on the edge portion of the cleaning blade receives pressure and frictional heat with the image carrier. When a low-melting-point toner is used, the toner easily undergoes plastic deformation due to pressure and heat and is easily crushed, and the shape can be easily changed to a flat shape. Flat toner tends to slip through the cleaning blade. For this reason, when a low-melting-point toner is used, the toner tends to slip through the cleaning blade. The flat toner passing through the cleaning blade adheres to the image carrier and moves, and reaches the cleaning blade again. Then, it receives pressure and heat again and slips through the cleaning blade. By repeating this, the toner adheres firmly to the image carrier, and the firmly attached toner becomes a nucleus, and agglomerates with other toners to become enormous and cause toner fixation. When the toner adheres to the image carrier, charging failure and latent image formation failure are caused, and an abnormal image is generated.

  As described above, the problem of toner fixing to the image carrier in the image forming apparatus that removes the toner remaining on the image carrier using the cleaning blade has been described using the low melting point toner. However, the present invention is not limited to this. This is a problem that may occur with other toners.

  The present invention has been made in view of the above problems, and an object of the present invention is to suppress toner adhesion to an image carrier in an image forming apparatus that removes toner remaining on the image carrier using a cleaning blade. An object of the present invention is to provide an image forming apparatus that can perform the above-described process.

In order to achieve the above object, the invention of claim 1 is directed to a latent image forming means for forming an electrostatic latent image on an image carrier that moves on the surface, and development for developing the electrostatic latent image on the image carrier. An image forming apparatus comprising: a means and a cleaning blade that presses a tip ridge line portion on the image carrier and removes toner remaining without being transferred from the image carrier onto the transfer member;
A cleaning assisting means is provided on the downstream side of the cleaning blade with respect to the surface movement direction of the image carrier to contact the toner adhered on the image carrier and weaken the adhesion between the toner and the image carrier. It is characterized by this.

  In the present invention, the cleaning auxiliary means provided on the downstream side of the cleaning blade comes into contact with the toner that has adhered to the image carrier and passed through the cleaning blade, and weakens the adhesion between the toner and the image carrier. The toner whose adhesion with the image carrier is weakened is easily removed by the cleaning blade when it reaches the cleaning blade again as the surface of the image carrier moves. For this reason, it can be suppressed that the toner attached to the image carrier repeatedly passes through the cleaning blade and adheres firmly to the image carrier. As a result, it is possible to prevent the toner adhering firmly from becoming a nucleus and aggregating with other toners to cause toner fixation.

  According to the present invention, in an image forming apparatus that removes toner remaining on an image carrier using a cleaning blade, there is an excellent effect that toner adhesion to the image carrier can be suppressed.

1 is an overall schematic diagram of a copier according to an embodiment. 1 is a schematic configuration diagram of a developing device employed in a copying machine. FIG. 3 is a first perspective explanatory view of the developing device. FIG. 6 is a second perspective explanatory view of the developing device. Cross-sectional explanatory drawing of a developing device. The perspective view which shows a part of developing device with sectional drawing. FIG. 3 is an enlarged perspective view of the vicinity of one end of the developing device, with the lower case not shown. FIG. 8 is an enlarged perspective view of the developing device from which the developing roller is omitted from the state of FIG. 7. FIG. 4 is an enlarged perspective view of the vicinity of the other end of the developing device, with the lower case not shown. FIG. 10 is an enlarged perspective view of the developing device from which the developing roller is omitted from the state of FIG. 9. FIG. The side view of a developing roller. Explanatory drawing of the surface shape of a developing roller, (a) is a schematic diagram of the whole developing roller, (b) is an enlarged view of a part of the surface of the developing roller. The perspective explanatory view of a supply roller. The side view of a supply roller. The perspective explanatory drawing of a doctor blade. The side view of a doctor blade. FIG. Side view of paddle. FIG. 3 is a configuration diagram of cleaning assisting means according to the first embodiment. Explanatory drawing of contact angle adjustment of the cleaning assistance means which concerns on Example 1. FIG. FIG. 6 is a configuration diagram of a cleaning assisting unit according to the second embodiment. FIG. 6 is a configuration diagram of a cleaning auxiliary unit according to the third embodiment. FIG. 10 is a configuration diagram of a cleaning auxiliary unit according to a fourth embodiment. FIG. 10 is a configuration diagram of cleaning assisting means according to a fifth embodiment. FIG. 10 is a configuration diagram of cleaning assisting means according to a sixth embodiment. FIG. 10 is a configuration diagram of cleaning assisting means according to a seventh embodiment. FIG. 10 is an operation explanatory view of a cleaning auxiliary unit according to an eighth embodiment. 10 is a control flowchart of a cleaning auxiliary unit according to the eighth embodiment. FIG. 10 is an explanatory diagram of a region where a cleaning assisting unit according to an eighth embodiment contacts and separates from a photoconductor. FIG. 10 is an operation explanatory view of the cleaning assisting means according to the ninth embodiment. FIG. 10 is an explanatory diagram of an example of area division of the cleaning assisting unit according to the ninth embodiment. Schematic block diagram of a conventional cleaning device.

Hereinafter, an embodiment in which the present invention is applied to a copying machine as an image forming apparatus will be described.
FIG. 1 is an overall schematic diagram of a copier 500 according to the present embodiment. The copying machine 500 includes a copying machine main body (hereinafter referred to as a printer unit 100), a paper feed table (hereinafter referred to as a paper feed unit 200), and a scanner (hereinafter referred to as a scanner unit 300) attached to the printer unit 100. .

The printer unit 100 includes a process cartridge 1 (Y, M, C, K) as four process units, an intermediate transfer member that is stretched by a plurality of stretching rollers and moves in the direction of arrow A in FIG. A transfer belt 7 is provided. Further, an exposure device 6 as an exposure unit, a fixing device 12 as a fixing unit, and the like are provided.
The suffixes Y, M, C, and K attached to the four process cartridges 1 indicate the specifications for yellow, magenta, cyan, and black. The four process cartridges 1 (Y, M, C, and K) have substantially the same configuration except that the colors of the toners to be used are different. Therefore, the subscripts K, Y, M, and C are omitted below. I will explain.

  The process cartridge 1 integrally supports a photosensitive member 2 as a latent image carrier, a charging member 3 as a charging means, a developing device 4 as a developing means, and a cleaning device 5 as a cleaning means. It has become the composition. Each process cartridge 1 can be attached to and detached from the copying machine 500 main body by releasing a stopper (not shown).

The photoconductor 2 rotates in the clockwise direction in the figure as indicated by the arrow in the figure. The charging member 3 is a roller-shaped charging roller, is in pressure contact with the surface of the photoconductor 2, and is rotated by the rotation of the photoconductor 2. At the time of image formation, a predetermined bias is applied to the charging member 3 by a high voltage power source (not shown) to charge the surface of the photoreceptor 2. In the process cartridge 1 of the present embodiment, the roller-shaped charging member 3 that contacts the surface of the photoreceptor 2 is used as the charging unit, but the charging unit is not limited to this, and non-contact such as corona charging. A charging method may be used.
In the present embodiment, an image forming system that does not have a mechanism for applying a lubricant to a photoconductor is mounted for low cost and space saving.

The exposure device 6 exposes the surface of the photoconductor 2 on the surface of the photoconductor 2 based on the image information of the original image read by the scanner unit 300 or image information input from an external device such as a personal computer. An electrostatic latent image is formed. The exposure device 6 provided in the printer unit 100 uses a laser beam scanner system using a laser diode, but may have other configurations such as an exposure unit using an LED array.
The cleaning device 5 cleans residual toner remaining on the surface of the photoreceptor 2 that has passed through a position facing the intermediate transfer belt 7.

  The four process cartridges 1 form toner images for the respective colors of yellow, cyan, magenta, and black on the photoreceptor 2. The four process cartridges 1 are arranged in parallel in the surface movement direction of the intermediate transfer belt 7 and transfer the toner images formed on the respective photoreceptors 2 in order to be superimposed on the intermediate transfer belt 7 in order. A visible image is formed on the belt 7.

  In FIG. 1, a primary transfer roller 8 serving as a primary transfer unit is disposed at a position facing each photoconductor 2 across the intermediate transfer belt 7. A primary transfer bias is applied to the primary transfer roller 8 by a high voltage power source (not shown) to form a primary transfer electric field with the photosensitive member 2. By forming a primary transfer electric field between the photosensitive member 2 and the primary transfer roller 8, the toner image formed on the surface of the photosensitive member 2 is transferred to the surface of the intermediate transfer belt 7. One of a plurality of stretching rollers that stretch the intermediate transfer belt 7 is rotated by a drive motor (not shown), so that the intermediate transfer belt 7 moves in the direction of arrow A in the figure. A full color image is formed on the surface of the intermediate transfer belt 7 by sequentially transferring the toner images of the respective colors on the surface of the intermediate transfer belt 7 moving on the surface.

  With respect to the position where the four process cartridges 1 are opposed to the intermediate transfer belt 7, the intermediate transfer belt 7 is located on the downstream side in the surface movement direction with respect to the secondary transfer counter roller 9 a that is one of the stretching rollers. A secondary transfer roller 9 is disposed at a position facing the belt 7 across the belt 7. Thereby, a secondary transfer nip is formed with the intermediate transfer belt 7. A predetermined voltage is applied between the secondary transfer roller 9 and the secondary transfer counter roller 9a to form a secondary transfer electric field. The transfer paper P, which is a transfer material fed from the paper supply unit 200 and conveyed in the direction of arrow S in FIG. 1, passes through the secondary transfer nip. At this time, the full-color image formed on the surface of the intermediate transfer belt 7 is transferred to the transfer paper P by the secondary transfer electric field formed between the secondary transfer roller 9 and the secondary transfer counter roller 9a. .

A fixing device 12 is disposed downstream of the secondary transfer nip in the conveyance direction of the transfer paper P. The transfer paper P that has passed through the secondary transfer nip reaches the fixing device 12, the full color image transferred onto the transfer paper P is fixed by heating and pressurization in the fixing device 12, and the transfer paper P on which the image is fixed is The data is output outside the copying machine 500.
On the other hand, the toner remaining on the surface of the intermediate transfer belt 7 without being transferred to the transfer paper P at the secondary transfer nip is collected by the transfer belt cleaning device 11.

As shown in FIG. 1, above the intermediate transfer belt 7, toner bottles 400 (Y, M, C, and K) that store toner of various colors are detachably disposed with respect to the copying machine 500 main body.
The toner stored in each color toner bottle 400 is supplied to each color developing device 4 by a toner replenishing device (not shown) corresponding to each color.

Next, the developing device 4 will be described.
FIG. 2 is a schematic diagram showing a schematic configuration of the developing device 4 employed in the copier of FIG. 1, and is a cross-sectional view seen from the back side in FIG.
3 and 4 are perspective explanatory views of the developing device 4, and are perspective explanatory views of the developing device 4 as viewed obliquely from above in different directions.
The developing casing 41 that forms the outer shape of the developing device 4 is formed by combining an upper case 411, an intermediate case 412, and a lower case 413. The middle case 412 forms a toner accommodating portion 43, and the upper case 411 is formed with a toner replenishing port 55 that is a developer replenishing portion that communicates the toner accommodating portion 43 with the outside. The upper case 411 is provided with an inlet seal 47 that seals a gap between the developing roller 42 and the upper case 411.

  FIG. 5 is a cross-sectional explanatory view of the developing device 4 viewed from the same direction as FIG. 2, and FIG. 6 is an enlarged perspective view of a part of the developing device 4, and a part thereof is a Z-X sectional view. It is explanatory drawing shown.

The middle case 412 is provided with a developing roller 42, a supply roller 44, a doctor blade 45, a paddle 46, a supply screw 48, a remaining toner sensor 49, and the like.
The developing device 4 is provided with an opening 56 that communicates the inside and the outside along the longitudinal direction (Y-axis direction in the figure). A cylindrical developing roller 42 is provided in the opening 56 to carry and carry the toner from the inside to the outside (developing area α facing the photoconductor).

FIG. 7 is an enlarged perspective view of the vicinity of one end (the rear end in FIG. 1) of the developing device 4 in which the lower case 413 is not shown, and FIG. 8 shows the developing roller 42 from the state of FIG. FIG. 2 is an enlarged perspective view of the developing device 4 in which FIG.
FIG. 9 is an enlarged perspective view of the vicinity of the other end (the front side end in FIG. 1) of the developing device 4 in which the lower case 413 is not shown, and FIG. 10 shows the developing roller 42 from the state of FIG. FIG. 2 is an enlarged perspective view of the developing device 4 in which FIG.

In the developing device 4, the supply roller 44 rotates and moves in the direction of arrow C in FIG. 2 (clockwise direction in FIG. 2), so that the toner T in the toner storage portion 43 faces the developing roller 42. Then, the toner is supplied to the surface of the developing roller 42. The developing roller 42 carries the supplied toner on the surface, rotates in the direction of arrow B in FIG. 2 (clockwise direction in FIG. 2), and moves on the surface, thereby removing the toner on the developing roller 42. The toner is conveyed to a portion facing the doctor blade 45 that is regulated to a predetermined amount. The toner regulated to a predetermined amount at the portion facing the doctor blade 45 reaches the developing area α which is the portion facing the photoreceptor 2 by the rotation of the developing roller 42.
In the supply nip β, the surface of the supply roller 44 moves from below to above, and the surface of the developing roller 42 moves from above to below.

In the developing area α, the toner T on the surface of the developing roller 42 is generated according to the developing electric field formed by the potential difference between the developing bias applied from the developing bias power source 142 to the developing roller 42 and the latent image on the surface of the photoreceptor 2. Moves to the surface of the photoreceptor 2. The moved toner adheres to the electrostatic latent image portion on the surface of the photoreceptor 2 and is developed. The photoreceptor 2 rotates in the direction of arrow D in FIG. 2 without contact with the developing roller 42. For this reason, in the development area α, the surface movement direction of the developing roller 42 and the surface movement direction of the photosensitive member 2 are the same direction.
The development bias power supply 142 is configured to develop the toner with the toner conveyed to the development area α, and the second voltage directs the toner from the developing roller 42 to the photosensitive member 2 and the second voltage directs the toner from the photosensitive member 2 to the developing roller 42. The voltage application unit applies an alternating voltage having a voltage to the developing roller 42.

Although details will be described later, the surface of the developing roller 42 has a regular uneven shape in which the height of the convex portion 42a and the depth of the concave portion 42b are substantially constant.
The toner T on the surface of the developing roller 42 that does not contribute to development in the developing area α and passes through the developing area α is collected by the supply roller 44 at the supply nip β, and the surface of the developing roller 42 is reset.

The toner T carried in the concave portions 42b regularly formed on the surface of the developing roller 42 is difficult to be collected. Then, when the toner T that has passed through the developing region α passes through the supply nip β and remains carried on the developing roller 42, the toner T adheres to the developing roller 42 and toner filming occurs. When toner filming occurs, the charge amount per unit weight of the toner T on the developing roller 42 and the toner amount per unit area of the developing roller 42 become unstable, causing density unevenness during development.
In the developing device 4 of the present embodiment, the surface movement direction of the developing roller 42 and the surface movement direction of the supply roller 44 are opposite in the supply nip β where the developing roller 42 and the supply roller 44 face each other. As a result, the linear velocity difference between the surface of the developing roller 42 and the surface of the supply roller 44 at the supply nip β increases, and the recovery performance of the supply roller 44 at the supply nip β can be improved. Therefore, it is possible to suppress the toner from being held on the developing roller 42, to suppress the toner from adhering to the surface of the developing roller 42, and to cause the developer to adhere to the surface of the developer carrying member. The occurrence of density unevenness during development can be suppressed.
In the developing device 4 of this embodiment, the linear speed ratio between the developing roller 42 and the supply roller 44 is the surface movement speed of the developing roller 42: the surface movement speed of the supply roller 44 = 1: 0.85. However, the linear speed ratio is not limited to this value.

  Further, it is desirable that the linear velocity of the developing roller 42 is high. As shown in FIG. 2, in the developing device 4, the supply roller 44 is disposed above the toner storage unit 43, and the toner T in the toner storage unit 43 in a state where at least a part of the supply roller 44 stops the rotation of the paddle 46. It is designed to be above the surface of the material. An area downstream of the supply nip β with respect to the surface movement direction of the supply roller 44 (hereinafter referred to as a supply nip downstream area) is above the surface of the toner T. If the toner is filled in the downstream area of the supply nip, the toner filled in the downstream area of the supply nip prevents new toner from entering the downstream area of the supply nip, and development in the supply nip β is performed. There is a possibility that the efficiency of collecting toner from the roller 42 may be reduced. On the other hand, in the developing device 4 of the present embodiment, the downstream area of the supply nip is above the surface of the toner T, as shown in FIG. Therefore, the toner is not filled in the downstream area of the supply nip, and the toner existing in the downstream area of the supply nip does not hinder the collection of the toner from the developing roller 42 in the supply nip β. Therefore, the toner can be efficiently collected and the toner resetting property can be improved.

Next, the developing roller 42 will be described.
FIG. 11 is an explanatory perspective view of the developing roller 42, and FIG. 12 is a side view of the developing roller 42. 13 is an explanatory diagram of the surface shape of the developing roller 42, FIG. 13A is a schematic diagram of the entire developing roller 42, and FIG. 13B is shown in FIG. 13A. 3 is an enlarged view of a part of the surface of the developing roller 42. FIG.

The developing roller 42 has a configuration in which a developing roller cylindrical portion 420 that carries toner on the surface thereof is provided on the developing roller shaft 421, and the developing roller shafts in the vicinity of both axial end portions that are axially outside the developing roller cylindrical portion 420. A spacer 422 is provided at 421.
The developing roller 42 is provided so as to be rotatable about the developing roller shaft 421, and is arranged so that the axial direction of the developing roller shaft 421 is parallel to the longitudinal direction (Y-axis direction in the drawing) of the developing device 4. Yes. Both ends of the developing roller shaft 421 in the axial direction of the developing roller 42 are rotatably attached to the side wall portion 412s of the middle case 412. A part of the surface of the developing roller 42 is exposed to the outside of the developing device 4 from the opening 56, and the developing roller 42 is moved from the lower side to the upper side to convey the toner so that the toner is conveyed in FIG. It rotates in the direction of arrow B.
Further, in the developing roller 42, the distance between the surface of the developing roller cylindrical portion 420 and the surface of the photosensitive member 2 in the developing region α is obtained by the spacers 422 provided in the vicinity of both ends in the axial direction contacting the surface of the photosensitive member 2. (Development gap) is kept constant.

The developing roller 42 is a member made of aluminum alloy, iron alloy, or the like.
As shown in FIG. 13A, the developing roller cylindrical portion 420 of the developing roller 42 is mainly divided into two portions (a groove forming portion 420a and a non-groove forming portion 420b) based on the difference in the surface structure. .
The groove forming portion 420a is a portion including a central portion in the axial direction of the developing roller 42, and is provided with a concavo-convex process on the surface thereof in order to properly carry the toner. In the present embodiment, a so-called rolling process is used as the concavo-convex process, and the convex portion 42a is formed by being surrounded by spiral first grooves L1 and second grooves L2 having different winding directions. In the developing roller 42 of the present embodiment, the pitch width W1 in the axial direction of the convex portion 42a is 80 [μm], and the axial length W2 of the top surface of the convex portion 42a is 40 [μm]. Furthermore, the depth of the recess, which is the height from the recess 42b to the top surface of the projection 42a, is 10 [μm]. The values of the pitch width W1, the axial length W2 of the top surface, and the depth of the recess are examples, and are not limited to these values.

  The surface of the developing roller 42 is desirably a material that normally charges the toner. Even when the low-charged toner is produced by the filming, the low-charged toner knocked out by the jumped toner T can be charged at the portions where the convex portions 42a and the concave portions 42b are not filmed. For this reason, low-charge toner can be reduced, and the image density is stabilized.

  Further, it is desirable that the surface material of the developing roller 42 is harder than the doctor blade 45 (blade member 450). This makes it difficult for the convex portion 42a on the surface of the developing roller 42 to be scraped by the doctor blade 45, so that the volume of the concave portion 42b surrounded by the convex portion 42a and the doctor blade 45 is difficult to change, and the M / A value (on the surface of the developing roller) The amount of toner carried per unit area) is stabilized.

  The height of the convex portion 42a of the developing roller 42 is desirably larger than the weight average particle diameter of the toner T to be used. Since the toner T having an average size is accommodated in the recess 42b, the selection of the particle size is difficult to occur, and the M / A value (the amount of toner carried per unit area on the surface of the developing roller) is stabilized over time. .

Next, the supply roller 44 will be described.
FIG. 14 is an explanatory perspective view of the supply roller 44, and FIG. 15 is a side view of the supply roller 44. A cylindrical supply roller 44 is provided on the developing roller 42 side above the toner container 43 inside the developing device 4. The supply roller 44 has a configuration in which a cylindrical foam material is wound around a supply roller shaft 441 that is a shaft portion thereof, and the cylindrical foam material becomes a supply roller cylindrical portion 440 that carries toner on the surface thereof. .

The supply roller 44 is configured to be rotatable about a supply roller shaft 441, and the shaft is attached to the side wall portion 412 s of the middle case 412 so as to be rotatable. The supply roller 44 is disposed so that a part of the outer peripheral surface of the supply roller cylindrical portion 440 is in contact with the outer peripheral surface of the developing roller cylindrical portion 420 of the developing roller 42 at the supply nip β. As shown, the supply roller shaft 441 is disposed above the developing roller shaft 421.
Further, as described above, the supply roller 44 rotates so that the surface moves in the direction opposite to the surface movement direction of the developing roller 42 at the supply nip β that is a portion facing the developing roller 42. Further, as shown in FIG. 2, the developing device 4 is arranged such that the position of the supply nip β is positioned above the contact position of the doctor blade 45 with respect to the developing roller 42.

  The supply roller 44 uses a foam material for the supply roller cylindrical portion 440, and the surface layer in contact with the developing roller 42 is a sponge layer in which a large number of micropores are dispersed on the surface. By making the surface layer of the supply roller 44 into a sponge shape, the supply roller 44 can easily reach the bottom of the recess 42b, so that the resetability of the toner on the developing roller 42 is improved.

  Further, the amount of biting of the supply roller 44 with respect to the development roller 42 (“radius of the development roller 42” + “radius of the supply roller 44” − “distance between the axes of the development roller 42 and the supply roller 44”) It is set to be larger than the height of the convex portion 42a. By making the amount of biting of the supply roller 44 larger than the height of the convex portion 42a, the toner resetting property in the concave portion 42b can be improved. Note that if the amount of biting of the supply roller 44 with respect to the developing roller 42 is too large relative to the height of the convex portion 42a, the toner will be pushed into the concave portion 42b and cause aggregation, so the amount of biting will not be too large. It is necessary to set as follows.

The foam material used for the supply roller cylindrical portion 440 of the supply roller 44 is set to an electric resistance value of 10 ³ to 10 ¹⁴ [Ω].
A supply bias is applied to the supply roller 44 by a supply bias power supply 144 to assist the operation of pressing the toner preliminarily charged at the supply nip β against the developing roller 42. The supply roller 44 rotates in the clockwise direction in FIGS. 2 and 5 to apply and supply the developer adhered on the surface to the surface of the developing roller 42.

  The voltage applied to the supply roller 44 by the supply bias power supply 144 is opposite to the normal charging polarity of the toner (negative polarity in the toner T of the present embodiment) with respect to the alternating voltage applied to the developing roller 42. Apply polarity (positive polarity) DC voltage. At this time, the voltage applied to the supply roller 44 is opposite in polarity (plus polarity) to the normal charging polarity of the toner than the voltage applied to the developing roller 42. As a result, an electric field in the direction in which the toner T is attracted toward the supply roller 44 with respect to the development roller 42 is formed in the supply nip β, and the resetability of the toner on the development roller 42 can be improved. Note that the configuration including the supply bias power supply 144 requires a separate DC power supply, which increases the cost. Therefore, the supply bias power supply 144 may not be provided according to the specifications of the developing device 4.

Next, the doctor blade 45 will be described.
FIG. 16 is an explanatory perspective view of the doctor blade 45, and FIG. 17 is a side view of the doctor blade 45.
As shown in FIGS. 5 to 10, a doctor blade 45 is provided in the middle case 412 that is located below the developing roller 42 and inside the lower case 413.
The doctor blade 45 includes a blade member 450 that is a thin plate-like metal member, and a metal base portion 452 to which one end of the blade member 450 is fixed. The other end side of the blade member 450 is configured to come into contact with the developing roller 42. The contact state of the blade member 450 with respect to the developing roller 42 may be either a tip contact state in which the tip contacts or a stomach contact state in which the surface portion on the base side from the tip contacts. However, in the state where the tip is applied, the toner present on the top surface of the convex portion 42a can be worn out, and only the toner present in the concave portion 42b is conveyed to the developing region α, whereby the toner conveyed to the developing region α. It is more preferable because the amount is stable.

  The blade member 450 of the doctor blade 45 is fixed to the pedestal portion 452 by a plurality of rivets 451. The pedestal portion 452 is made of a metal that is thicker than the blade member 450 and functions as a substrate for fixing the blade member 450 to the main body of the developing device 4 (side surface portion of the middle case 412). A pin hole 454 is provided at the longitudinal end of the pedestal portion 452, one is a perfect circular main reference hole 454 a, and the other is an elliptical secondary reference hole having a long diameter in the direction of the main reference hole 454 a. 454b. When a pin (not shown) enters the main reference hole 454a, the position of the pedestal portion 452 with respect to the main body of the developing device 4 is determined and supported by the sub reference hole 454b. The pedestal portion 452 to which the blade member 450 is fixed is fixed to the developing device 4 main body (inner case 412) with a doctor fixing screw 455, whereby the blade member 450 is fixed to the developing device 4.

  The blade member 450 of the doctor blade 45 is made of a metal plate spring material such as SUS304CSP, SUS301CSP, or phosphor bronze, and the free end is brought into contact with the surface of the developing roller 42 with a pressing force of 10 to 100 [N / m]. Is. The blade member 450 regulates the toner that has passed under the pressing force to a predetermined amount and applies electric charge by frictional charging. Further, a bias is applied to the blade member 450 from a doctor bias power source 145 to assist frictional charging.

  Further, the blade member 450 of the doctor blade 45 is desirably conductive. Since the blade member 450 is conductive, the charge amount of the toner T having a large Q / M value (charge amount per unit volume) can be lowered, and the Q / M value of the toner T can be made uniform. it can. Thereby, sticking of the toner T to the developing roller 42 can be prevented.

  The voltage applied to the doctor bias power supply 145 blade member 450 is configured such that a DC voltage can be applied in the range of ± 200 [V] with respect to the alternating voltage applied to the developing roller 42, and the DC voltage depends on the usage environment. It is good also as a structure which can control the value of. Thereby, it is possible to suppress fluctuations in the M / A value (toner carrying amount per unit area on the surface of the developing roller) due to environmental fluctuations.

Next, the paddle 46 will be described.
18 is a perspective explanatory view of the paddle 46, and FIG. 19 is a side view of the paddle 46. As shown in FIG.
A toner accommodating portion 43 is provided in the developing device 4 as a space for accommodating toner, and a paddle 46 is rotatably attached to the developing casing 41 in the toner accommodating portion 43.

The paddle 46 includes a paddle shaft 461 that is a shaft portion thereof, and paddle blades 460 as thin blade members made of an elastic sheet material such as Mylar. The paddle shaft 461 has two flat portions facing each other, and paddle blades 460 are respectively attached to the two flat portions. The two paddle blades 460 are fixed to the flat portion of the paddle shaft 461 so as to protrude in opposite directions around the paddle shaft 461.
The base portion of the paddle blade 460 is provided with a plurality of holes arranged in parallel so as to be parallel to the axial direction of the paddle shaft 461. The paddle shaft 461 has a plurality of protrusions so as to be parallel to the axial direction thereof. The parts are arranged side by side. Then, the paddle blades 460 are fixed to the paddle shafts 461 by inserting the convex portions of the paddle shafts 461 into the holes of the paddle blades 460 and performing heat caulking.

  The paddle 46 is disposed so that the axial direction of the paddle shaft 461 is parallel to the longitudinal direction of the developing device 4 (Y-axis direction in the figure). Both ends in the axial direction of the paddle shaft 461 are rotatably attached to the side wall portion 412s of the middle case 412.

In the paddle 46, the protruding amount of the paddle blade 460 is set to such a length that the tip of the paddle blade 460 extending from the paddle shaft 461 contacts the inner wall surface of the toner containing portion 43. As shown in FIGS. 2 and 5, the bottom surface portion 43 b of the toner accommodating portion 43 has an arc shape along the rotation direction of the paddle 46, and the paddle blade 460 is moved by the rubbing operation accompanying the rotation of the paddle 46. 43 is prevented from being caught by the bottom surface portion 43b.
On the developing roller 42 side of the toner containing portion 43, a side wall surface portion 43s that rises vertically from the bottom surface portion 43b is formed. The side wall surface portion 43 s is horizontal in the direction toward the roller parallel to the X axis at a level that is equal to or slightly lower than the center of the paddle shaft 461, and forms a stepped portion 50.

  The distance between the side wall surface portion 43s and the paddle shaft 461 is set shorter than the distance between the bottom surface portion 43b and the paddle shaft 461. Therefore, the paddle blade 460 that has rubbed the bottom surface portion 43b hits the side wall surface portion 43s and bends more greatly. Thereafter, when the tip of the paddle wing 460 reaches the stepped portion 50, there is nothing to hold the paddle wing 460, and the tip of the paddle wing 460 is released and jumps upward. By such movement of the paddle blade 460, the toner is splashed upward, and is stirred, conveyed, and supplied.

  The step portion 50 is a horizontal plane parallel to the XY plane, and is formed to extend in the longitudinal direction of the developing device 4 (Y-axis direction in the drawing). In the developing device 4 of the present embodiment, the step portion 50 is provided in the entire region in the width direction, but may be provided in a part of the developing device 4 as long as the paddle blade 460 jumps up.

  The supply screw 48 is a screw member that becomes a supply screw shaft 481 and a supply screw blade portion 480 which is a spiral blade portion fixed to the supply screw shaft 481. The supply screw shaft 481 is provided so as to be rotatable, and the axial direction of the supply screw shaft 481 is arranged so as to be parallel to the longitudinal direction of the developing device 4 (Y-axis direction in the drawing). Both axial ends of the supply screw shaft 481 are rotatably attached to the side wall portion 412s of the middle case 412.

  The end of the supply screw 48 in the axial direction is positioned below a toner supply port 55 formed at the end of the developing device 4 in the longitudinal direction. Then, when the supply screw 48 is rotated, the spiral supply screw blade 480 conveys the toner replenished from the toner replenishing port 55 toward the central portion of the developing device 4 in the longitudinal direction.

  A sheet member such as Mylar is attached as an inlet seal 47 along the longitudinal direction to the edge portion forming the opening 56 of the upper case 411. The inlet seal 47 is a substantially rectangular sheet, one end of which is affixed to the edge portion of the upper case 411, and the other end is a free end. The free end side of the inlet seal 47 protrudes toward the inside of the developing device 4, and is further provided so as to contact the developing roller 42. The inlet seal 47 is fixed to the upper case 411 on the upstream side in the rotational direction of the developing roller 42, and the downstream side in the rotational direction of the developing roller 42 is a free end, and the surface portion of the inlet seal 47 contacts the developing roller 42. It is arranged to do. Further, the inner side of the developing device 4 of the upper case 411 is curved so as to follow the upper shape of the supply roller 44, and the gap between the curved surface of the upper case 411 and the surface of the supply roller 44 is 1 0.0 [mm].

As shown in FIGS. 7 to 10, side seals 59 are attached to a part of the middle case 412 corresponding to both longitudinal ends of the opening 56 of the developing device 4. The side seal 59 is provided on the inner side in the axial direction with respect to the spacer 422 provided in the vicinity of both ends in the axial direction of the developing roller 42, and in a region where the axial end where the doctor blade 45 contacts the developing roller 42 overlaps. ing. Such a side seal 59 prevents the toner from leaking from the end portion in the longitudinal direction of the opening 56 in the developing casing 41.
A remaining toner sensor 49 provided in the middle case 412 detects the amount of toner in the toner storage unit 43.

Next, the movement of toner in the developing device 4 will be described.
The toner replenished into the developing device 4 from the toner replenishing port 55 is supplied to the toner accommodating portion 43 by the supply screw 48 and stirred by the paddle 46. Further, the paddle 46 is flipped up in the direction of the developing roller 42 and the supply roller 44 and conveyed. The toner supplied to the supply roller 44 is delivered to the surface of the developing roller 42 at a supply nip β where the supply roller 44 contacts the developing roller 42. Of the toner delivered to the surface of the developing roller 42, the amount of toner exceeding a predetermined amount conveyed to the developing area α is scraped off from the surface of the developing roller 42 by the doctor blade 45.

  The toner remaining on the surface of the developing roller 42 that has passed through the portion facing the doctor blade 45 is conveyed as it is by the surface moving method by the rotation of the developing roller 42, and reaches the developing region α facing the photoreceptor 2. The toner that has passed through the development region α without being used for development passes through a position where the inlet seal 47 contacts, and is conveyed to the supply nip β that is a position facing the supply roller 44. The toner that has reached the supply nip β by the developing roller 42 is scraped off from the surface of the developing roller 42 by the supply roller 44 and conveyed by the supply roller 44.

Next, toner used in the copying machine 500 of this embodiment will be described.
As the toner used in the copying machine 500, a toner having excellent low-temperature fixability is used. Specifically, a toner composition containing a modified polyester resin capable of reacting with a compound having an active hydrogen group in an organic solvent is dissolved and / or dispersed, and the solution or dispersion is dissolved in an aqueous medium containing resin fine particles. , A toner obtained by reacting with a crosslinking agent and / or an extender. Further, the toner binder of this toner contains a crystalline polyester resin together with the modified polyester resin.

Hereinafter, the toner will be described in detail.
(Effect of crystalline polyester)
Since the crystalline polyester resin in the toner used in the copying machine of the present embodiment has crystallinity, it exhibits a thermal melting characteristic that shows a rapid viscosity decrease near the fixing start temperature. In other words, the toner has good heat-resistant storage stability due to crystallinity until just before the melting start temperature, and suddenly drops in viscosity (sharp melt) at the melting start temperature and fixes, so it has both good heat storage stability and low-temperature fixability. Can be designed. It was also found that good results were obtained with respect to the release width (difference between the fixing lower limit temperature and the hot offset occurrence temperature).

(Circularity and circularity distribution)
It is important that the toner has a specific shape and shape distribution, and an irregularly shaped toner having an average circularity of less than 0.95 and too far from the spherical shape has a satisfactory transferability and high dust-free toner. A quality image cannot be obtained. As a method for measuring the shape, an optical detection band method is suitable in which a suspension containing particles is passed through an imaging unit detection band on a flat plate, and a particle image is optically detected and analyzed by a CCD camera. A toner with an average circularity of 0.99 to 0.95, which is a value obtained by dividing the perimeter of an equivalent circle having the same projected area obtained by this method by the perimeter of the actual particle, has a high density with a reproducibility of an appropriate density. It was found to be effective in forming a clear image. More preferably, particles having an average circularity of 0.99 to 0.96 and a circularity of less than 0.96 are 10% or less. The value of the average circularity can be measured as the average circularity by a flow type particle image analyzer FPIA-2000 (manufactured by Toa Medical Electronics Co., Ltd.). As a specific measuring method, 0.1 to 0.5 ml of a surfactant, preferably alkylbenzene sulfonate is added as a dispersant to 100 to 150 ml of water from which impure solids have been removed in advance, and further measurement is performed. Add about 0.1-0.5g of sample. The suspension in which the sample is dispersed is obtained by performing dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and measuring the shape and distribution of the toner with the above apparatus at a dispersion concentration of 3000 to 10,000 / μl. .

(Dv / Dn (ratio of volume average particle diameter / number average particle diameter))
Dry toner having a volume average particle diameter (Dv) of 4 to 8 μm and a ratio (Dv / Dn) to the number average particle diameter (Dn) of 1.25 or less, preferably 1.05 to 1.20. It is. Thereby, it is excellent in all of heat-resistant storage stability, low-temperature fixability, and hot offset resistance, and in particular, it is excellent in image gloss when used in a full-color copying machine. When used as a one-component developer, fluctuations in the particle diameter of the toner are reduced even if the balance of the toner is performed. In addition, there is no filming of toner on the developing roller and no toner fusion to a member such as a blade for thinning the toner, and the development is stable and stable even in long-term use (stirring) of the developing device. Sex and images were obtained.

In general, it is said that the smaller the particle size of the toner, the more advantageous it is to obtain a high-resolution and high-quality image, but it is disadvantageous for transferability and cleaning properties. is there. Further, when the volume average particle diameter is smaller than the above range, or when used as a one-component developer, toner filming on the developing roller or toner on a member such as a blade for thinning the toner It becomes easy to generate the fusion. These phenomena are the same for toner having a high content of fine powder.
Conversely, when the toner particle size is larger than the above range, it becomes difficult to obtain a high-resolution and high-quality image, and the toner particle size when the balance of the toner in the developer is performed. In many cases, fluctuations of It was also clarified that the same applies when the volume average particle diameter / number average particle diameter is larger than 1.25.
Further, when the volume average particle size / number average particle size is smaller than 1.05, there are preferable aspects from the viewpoint of stabilizing the behavior of the toner and uniformizing the charge amount, but the toner can be sufficiently charged. It became clear that there were cases where it was not possible or the cleaning performance was deteriorated.

(Modified polyester resin)
Examples of the modified polyester resin (i) include polyester prepolymers modified with isocyanate or epoxy. This undergoes an extension reaction with a compound having an active hydrogen group (such as amines), and has an effect of improving the release width (difference between the minimum fixing temperature and the hot offset generation temperature). As a method for synthesizing the modified polyester resin (i), it can be easily synthesized by reacting a conventionally known isocyanate agent or epoxidizing agent with a base polyester resin. Isocyanating agents include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.); aromatic diisocyanates (Tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanurates; block the polyisocyanates with phenol derivatives, oximes, caprolactam, etc. And combinations of two or more of these. Moreover, epichlorohydrin etc. can be mentioned as the representative example as an epoxidizing agent.

  The ratio of the isocyanate agent is usually 5/1 to 1/1, preferably 4/1 to 1 as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the base polyester. 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. If the molar ratio of [NCO] is less than 1, the urea content in the modified polyester will be low, and the hot offset resistance will deteriorate. The content of the isocyanate agent in the modified polyester resin is usually 0.5 to 40% by weight, preferably 1 to 30% by weight, and more preferably 2 to 20% by weight. If it is less than 0.5% by weight, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40% by weight, the low-temperature fixability deteriorates.

  The number of isocyanate groups contained per molecule in the modified polyester resin is usually 1 or more, preferably 1.5 to 3 on average, and more preferably 1.8 to 2.5 on average. When the number is less than 1 per molecule, the molecular weight of the urea-modified polyester after the elongation reaction becomes low, and the hot offset resistance deteriorates. Examples of amines include diamine compounds, trivalent or higher polyamine compounds, amino alcohol compounds, amino mercaptan compounds, amino acid compounds, and compounds in which these amino groups are blocked. Examples of diamine compounds include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′dimethyldicyclohexylmethane, diaminecyclohexane, isophoronediamine). Etc.); and aliphatic diamines (ethylenediamine, tetramethylenediamine, hexamethylenediamine, etc.) and the like. Examples of the trivalent or higher polyamine compound include diethylenetriamine and triethylenetetramine. Examples of amino alcohol compounds include ethanolamine and hydroxyethylaniline. Examples of the amino mercaptan compound include aminoethyl mercaptan and aminopropyl mercaptan. Examples of amino acid compounds include aminopropionic acid and aminocaproic acid. Examples of the compounds in which these amino groups are blocked include ketimine compounds and oxazoline compounds obtained from the amines and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines, preferred are a diamine compound and a mixture of a diamine compound and a small amount of a polyamine compound. Moreover, amines can be used as a crosslinking agent and an extender.

  Furthermore, if necessary, the molecular weight of the urea-modified polyester can be adjusted using an elongation terminator. Examples of the elongation terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine and the like), and those obtained by blocking them (ketimine compounds).

  The ratio of amines is usually 1/2 to 2/1 as equivalent ratio [NCO] / [NHx] of isocyanate group [NCO] in modified polyester resin and amino group [NHx] in amines, preferably The ratio is 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] exceeds 2 or less than 1/2, the molecular weight of the urea-modified polyester after the elongation reaction becomes low, and the hot offset resistance deteriorates. In the present embodiment, the urea-modified polyester may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.

  The urea-modified polyester after the extension reaction in the present embodiment is produced by a one-shot method or a prepolymer method. The weight average molecular weight of the urea-modified polyester is usually 10,000 or more, preferably 20,000 to 10,000,000, and more preferably 30,000 to 1,000,000. If it is less than 10,000, the hot offset resistance deteriorates. The number average molecular weight of the urea-modified polyester is not particularly limited when using an unmodified polyester described later, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. When used alone, the number average molecular weight is usually 20000 or less, preferably 1000 to 10000, and more preferably 2000 to 8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color apparatus are deteriorated.

(Unmodified polyester)
In the present embodiment, not only the urea-modified polyester but also a polyester resin (ii) not modified with the urea-modified polyester can be contained as a toner binder component. By using (ii) in combination, the low-temperature fixability and glossiness when used in a full-color apparatus are improved, which is preferable to single use. The above (i) and (ii) are preferably at least partially compatible in terms of low temperature fixability and hot offset resistance. Accordingly, the polyester component (i) and (ii) preferably have similar compositions. The peak molecular weight of (ii) is usually 1000-30000, preferably 1500-10000, more preferably 2000-8000. If it is less than 1000, heat-resistant storage stability will deteriorate, and if it exceeds 10,000, low-temperature fixability will deteriorate. The weight average molecular weight of the unmodified polyester resin (ii) is preferably 2000 to 90000, and the glass transition point (Tg) is preferably 40 to 80 ° C. The hydroxyl value of (ii) is preferably 5 or more, more preferably 10 to 120, and particularly preferably 20 to 80. If it is less than 5, it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. The acid value of (ii) is usually 1-30, preferably 5-20. By having an acid value, it tends to be negatively charged. Further, those having an acid value and a hydroxyl value exceeding these ranges are easily affected by the environment under high temperature and high humidity and low temperature and low humidity, and are liable to cause image deterioration.

（式中、Ｒ１、Ｒ２は炭化水素基であり、その炭素数は１〜２０である。また、ｎは自然数である。）
また、結晶性ポリエステル樹脂の結晶性および軟化点を制御する方法として、ポリエステル合成時にアルコール成分にグリセリン等の３価以上の多価アルコールや、酸成分に無水トリメリット酸などの３価以上の多価カルボン酸を追加して縮重合を行った非線状ポリエステルなどを設計、使用するなどの方法が挙げられる。 (Crystalline polyester)
The crystalline polyester (iii) is a polyester having at least a melting point. Examples of the crystalline polyester (iii) include diol compounds having 2 to 6 carbon atoms, particularly alcohol components containing 1,4-butanediol, 1,6-hexanediol and derivatives thereof, maleic acid, and fumaric acid. A crystalline polyester resin having a repeating unit represented by the following general formula (1) synthesized using an acid component containing succinic acid and succinic acid is preferable.

(In the formula, R1 and R2 are hydrocarbon groups, and the number of carbon atoms is 1 to 20. Also, n is a natural number.)
In addition, as a method for controlling the crystallinity and softening point of the crystalline polyester resin, a trivalent or higher polyhydric alcohol such as glycerin as an alcohol component and a trivalent or higher polyvalent such as trimellitic anhydride as an acid component can be used during polyester synthesis. Examples thereof include a method of designing and using a non-linear polyester that has been subjected to condensation polymerization by adding a polyvalent carboxylic acid.

The molecular structure of the crystalline polyester can be confirmed by solid NMR. As for the molecular weight, as a result of intensive studies from the viewpoint that the above-mentioned molecular weight distribution is sharp and the low molecular weight is excellent in low-temperature fixability, the molecular weight distribution by GPC of the soluble part of o-dichlorobenzene is expressed by log (M ), The peak position of the molecular weight distribution diagram in which the vertical axis is expressed in weight% is in the range of 3.5 to 4.0, the half width of the peak is 1.5 or less, and the weight average molecular weight (Mw) is 1000 to 1000. It was found that 6500, the number average molecular weight (Mn) is 500 to 2000, and Mw / Mn is preferably 2 to 5. It has been found that the melting temperature and F1 / 2 temperature are desirably low so long as the heat resistant storage stability does not deteriorate, and are preferably in the range of 50 to 130 ° C.
When the melting temperature and F1 / 2 temperature are 50 ° C. or lower, heat-resistant storage stability deteriorates, and blocking tends to occur at the temperature inside the developing device. Sex cannot be obtained.
The dispersed particle diameter of the crystalline polyester resin in the toner is preferably 0.2 to 3.0 μm in major axis diameter.

  The acid value of the crystalline polyester is 8 mgKOH / g or more, more preferably 20 mgKOH / g or more in order to achieve the desired low-temperature fixability from the viewpoint of the affinity between paper and resin. Is preferred. On the other hand, in order to improve hot offset property, it is preferable that it is 45 mgKOH / g or less. Further, the hydroxyl value of the crystalline polymer is preferably 0 to 50 mgKOH / g, more preferably 5 to 50 mgKOH / g in order to achieve a predetermined low-temperature fixability and to achieve good charging characteristics. .

In the toner according to the exemplary embodiment, the weight ratio of (i), (ii), and (iii) in the toner is usually (i) / (ii) + (iii) in order to develop low-temperature fixability. 5/95 to 25/75, preferably 10/90 to 25/75, more preferably 12/88 to 25/75, particularly preferably 12/88 to 22/78, and (ii) and (iii ) Is 99/1 to 50/50, preferably 95/5 to 60/40, more preferably 90/10 to 65/35. Outside the above range, hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

In this embodiment, the glass transition point (Tg) of the toner binder is usually 40 to 70 ° C., preferably 40 to 65 ° C. If it is less than 40 ° C., the heat-resistant storage stability of the toner is deteriorated, and if it exceeds 70 ° C., the low-temperature fixability is insufficient. Due to the coexistence of the urea-modified polyester resin, the toner of the present embodiment tends to have good heat-resistant storage stability even when the glass transition point is low, as compared with a known polyester toner. As the storage elastic modulus of the toner binder, the temperature (TG ′) at which 10000 dyne / cm ² is obtained at a measurement frequency of 20 Hz is usually 100 ° C. or higher, preferably 110 to 200 ° C. If it is less than 100 ° C., the resistance to hot offset deteriorates. As the viscosity of the toner binder, the temperature (Tη) at 1000 poise at a measurement frequency of 20 Hz is usually 180 ° C. or lower, preferably 90 to 160 ° C. If it exceeds 180 ° C., the low-temperature fixability deteriorates. That is, TG ′ is preferably higher than Tη from the viewpoint of achieving both low temperature fixability and hot offset resistance. In other words, the difference between TG ′ and Tη (TG′−Tη) is preferably 0 ° C. or higher. More preferably, it is 10 degreeC or more, Most preferably, it is 20 degreeC or more. The upper limit of the difference is not particularly limited. Further, from the viewpoint of achieving both heat-resistant storage stability and low-temperature fixability, the difference between Tη and Tg is preferably 0 to 100 ° C. More preferably, it is 10-90 degreeC, Most preferably, it is 20-80 degreeC. In the molecular weight distribution of the THF-soluble component of the polyester resin contained in the toner, the molecular weight peak is 1000 to 30000, the molecular weight is 30,000 or more, the component is 1 to 80% by weight, and the number average molecular weight is 2000 to 15000. It is preferable that Further, in the molecular weight distribution of the THF-soluble component of the polyester resin contained in the toner, the component having a molecular weight of 1000 or less is preferably 0.1 to 5.0% by weight. The polyester resin contained in the toner preferably has a THF insoluble content of 1 to 15% by weight.

(Coloring agent)
As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher, Yellow lead, Titanium yellow, Polyazo yellow, Oil yellow, Hansa yellow (GR, A, RN, R), Pigment yellow L, Benzidine yellow (G, GR), Permanent yellow (NCG), Vulcan fast yellow (5G, R) ), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Phi Se Red, parachlor ortho nitro Nirin Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine B, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Tolujing Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thio Indigo red B, thioindigo maroon, oil red, quinacridone red, pyrazolone red, Riazo Red, Chrome Vermillion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), indigo, ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Lid Cyanine Green, anthraquinone green, titanium oxide, zinc white, lithopone and mixtures thereof can be used. The content of the colorant is usually 1 to 15% by weight, preferably 3 to 10% by weight, based on the toner.

  The colorant can also be used as a master batch combined with a resin. As the binder resin to be kneaded together with the production of the masterbatch or the masterbatch, in addition to the modified and unmodified polyester resins mentioned above, styrene such as polystyrene, poly p-chlorostyrene, polyvinyltoluene, and polymers of substituted products thereof; Styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer Styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α- Chloromethyl methacrylate copolymer, Tylene-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-malein Styrene copolymers such as acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, poly Acrylic resin, rosin, modified rosin, terpene resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. The

  This master batch can be obtained by mixing and kneading a resin for a master batch and a colorant under a high shear force to obtain a master batch. At this time, an organic solvent can be used to enhance the interaction between the colorant and the resin. There is also a so-called flushing method in which an aqueous paste containing water of a colorant is mixed and kneaded together with a resin and an organic solvent, the colorant is transferred to the resin side, and moisture and organic solvent components are removed. This flushing method is preferably used because the wet cake of the colorant can be used as it is and does not need to be dried. For mixing and kneading, a high shear dispersion device such as a three-roll mill is preferably used.

(Release agent)
Further, a wax may be contained together with the toner binder and the colorant. Known waxes can be used, for example, polyolefin wax (polyethylene wax, polypropylene wax, etc.); long chain hydrocarbon (paraffin wax, sasol wax, etc.); carbonyl group-containing wax, etc. Of these, carbonyl group-containing waxes are preferred. Examples of the carbonyl group-containing wax include polyalkanoic acid esters (carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18. -Octadecanediol distearate, etc.); polyalkanol ester (tristearyl trimellitic acid, distearyl maleate, etc.); polyalkanoic acid amide (ethylenediamine dibehenyl amide, etc.); polyalkylamide (tristearyl amide, trimellitic acid, etc.) And dialkyl ketones (such as distearyl ketone). Among these carbonyl group-containing waxes, polyalkanoic acid esters are preferred. The melting point of the wax is usually 40 to 160 ° C, preferably 50 to 120 ° C, more preferably 60 to 90 ° C. A wax having a melting point of less than 40 ° C. has an adverse effect on heat resistant storage stability, and a wax having a melting point of more than 160 ° C. tends to cause a cold offset during fixing at a low temperature. Further, the melt viscosity of the wax is preferably 5 to 1000 cps, more preferably 10 to 100 cps as a measured value at a temperature 20 ° C. higher than the melting point. Waxes exceeding 1000 cps have poor effects for improving hot offset resistance and low-temperature fixability. The content of the wax in the toner is usually 0 to 40% by weight, preferably 3 to 30% by weight.

(Charge control agent)
The toner of the exemplary embodiment may contain a charge control agent as necessary. All known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified). Quaternary ammonium salts), alkylamides, phosphorus simple substances or compounds, tungsten simple substances or compounds, fluorine-based activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. Specifically, Nitronine-based dye Bontron 03, quaternary ammonium salt Bontron P-51, metal-containing azo dye Bontron S-34, oxynaphthoic acid metal complex E-82, salicylic acid metal complex E- 84, E-89 of a phenol-based condensate (manufactured by Orient Chemical Industry Co., Ltd.), TP-302 of a quaternary ammonium salt molybdenum complex, TP-415 (manufactured by Hodogaya Chemical Industry Co., Ltd.), quaternary ammonium Copy charge PSY VP2038 of salt, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit), copper phthalocyanine, perylene, quinacridone Azo pigments, sulfonate group, carboxyl group, and polymer compounds having a functional group such as a quaternary ammonium salt.

  The amount of charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is not uniquely limited. However, it is preferably used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the main charge control agent is reduced, the electrostatic attractive force with the developing roller is increased, the flowability of the developer is reduced, and the image density is reduced. Incurs a decline. These charge control agents can be dissolved and dispersed after being melt-kneaded with a masterbatch and resin, and of course, they can be added directly when dissolved and dispersed in an organic solvent, or fixed on the toner surface after preparation of toner particles. May be.

(Resin fine particles)
The resin fine particles used in the toner of the present embodiment can be any resin as long as it can form an aqueous dispersion, and may be a thermoplastic resin or a thermosetting resin. For example, a vinyl resin, a polyurethane resin, Examples thereof include epoxy resins, polyester resins, polyamide resins, polyimide resins, silicon resins, phenol resins, melamine resins, urea resins, aniline resins, ionomer resins, and polycarbonate resins. As the resin fine particles, two or more of the above resins may be used in combination. Of these, vinyl resins, polyurethane resins, epoxy resins, polyester resins, and combinations thereof are preferred because an aqueous dispersion of fine spherical resin particles is easily obtained.
The vinyl resin is a polymer obtained by homopolymerization or copolymerization of a vinyl monomer, such as a styrene- (meth) acrylate resin, a styrene-butadiene copolymer, a (meth) acrylic acid-acrylate polymer, Examples include styrene-acrylonitrile copolymers, styrene-maleic anhydride copolymers, styrene- (meth) acrylic acid copolymers, and the like. It is preferable that the resin fine particles have a volume average particle diameter of 5 to 500 nm.

(External additive)
As the external additive for assisting the fluidity, developability and chargeability of the colored particles obtained in this embodiment, inorganic fine particles can be preferably used. The primary particle diameter of the inorganic fine particles is preferably 5 mμ to 2 μm, and particularly preferably 5 mμ to 500 mμ. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The use ratio of the inorganic fine particles is preferably 0.01 to 5% by weight of the toner, and particularly preferably 0.01 to 2.0% by weight. Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.

In addition, polymer fine particles such as polystyrene obtained by soap-free emulsion polymerization, suspension polymerization and dispersion polymerization, methacrylic acid ester and acrylic acid ester copolymer, polycondensation system such as silicone, benzoguanamine and nylon, thermosetting resin And polymer particles.
Such a fluidizing agent can be surface-treated to increase hydrophobicity and prevent deterioration of flow characteristics and charging characteristics even under high humidity. For example, silane coupling agents, silylating agents, silane coupling agents having an alkyl fluoride group, organic titanate coupling agents, aluminum coupling agents, silicone oils, modified silicone oils and the like are preferable surface treatment agents. .
Examples of the cleaning property improver for removing the developer after transfer remaining on the photoreceptor or the primary transfer medium include, for example, zinc stearate, calcium stearate, fatty acid metal salts such as stearic acid, such as polymethyl methacrylate fine particles, polystyrene fine particles, etc. And polymer fine particles produced by soap-free emulsion polymerization. The polymer fine particles preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.

Next, the cleaning device will be described. First, a conventional cleaning device will be described.
FIG. 33 is a schematic configuration diagram of a conventional photoconductor cleaning device, where (a) is a cross-sectional view and (b) is a bottom view. In FIG. 33, a part of the housing of the cleaning device 5 is shown, and the outer frame portion is not shown. The cleaning device 5 includes a strip-shaped cleaning blade 13 made of an elastic body such as polyurethane rubber. The base end portion of the cleaning blade 13 is supported by the support member 14. The support member 14 is fixed to a part 10 of the housing by screws 15 or the like. The edge portion of the cleaning blade 13 is pressed against the peripheral surface of the photoconductor 2 to block the toner remaining on the photoconductor 2 and scrape off and remove it.

However, when the low-melting-point toner containing the crystalline polyester as described above is used, there is a problem that the toner adheres to the photoreceptor 2 and an abnormal image appears. The mechanism by which the low melting point toner adheres to the photoreceptor is as follows.
1. The low-melting-point toner is developed on the image area of the photoreceptor 2 or adheres to the non-image area as a background stain.
2. Residual toner that could not be transferred in the transfer portion or reverse transfer toner that was reversely transferred onto the photoreceptor 2 from the intermediate transfer belt 7 reaches the position of the cleaning blade 13.
3. The cleaning blade 13 stops the toner and scrapes it off.
4). The toner that has not been scraped off receives frictional heat due to friction between the surface of the photoreceptor 2 and the cleaning blade 13. Further, the toner is drawn between the cleaning blade 13 and the photoreceptor 2, that is, into the nip portion due to friction. The low melting point toner is more easily plastically deformed when subjected to heat and pressure at the same time than the conventional toner. For this reason, the low melting point toner is crushed by receiving frictional heat and blade pressure.
5. The crushed toner passes through the nip portion and adheres to the photoreceptor 2.
6). The toner adhering to the photoreceptor 2 reaches the position of the cleaning blade 13 again as the surface of the photoreceptor 2 moves. The toner adhering to the photoconductor is not easily scraped off by the cleaning blade 13, and firmly adheres to the photoconductor 2 by passing through the cleaning blade again.
7). By repeating this, the toner adheres to the photosensitive member 2 more firmly, and the firmly attached toner becomes a nucleus, and aggregates with other toners to become enormous and the toner adheres to the aggregate.
When the toner is fixed, the charging of the photoconductor 2 and the latent image formation are poor, and an abnormal image is generated.

  Such toner sticking to the photoreceptor 2 is particularly noticeable in a copying machine using the above-described non-contact one-component developing device. In the two-component developing device, the toner that has passed through the cleaning blade is easily scraped off by magnetic spikes by a carrier that rotates at a high speed of the two-component developing device before becoming an aggregate. Also, the effect is less than that of a two-component developing device, but even a contact one-component developing device has an effect of scraping the toner that has passed through the cleaning blade with the developing device before it becomes an aggregate. ing. On the other hand, in the non-contact one-component developing device, since the developing device does not have an effect of scraping off the toner, it is considered that toner fixation occurs remarkably.

  Further, toner adhesion to the photosensitive member 2 occurs particularly noticeably in a copying machine using the low-melting-point toner containing the above-described crystalline polyester. This is presumably because the toner having a high melting point has little plastic deformation due to heat and pressure.

  In addition, in a copying machine that does not have a mechanism for applying a lubricant to the photosensitive member 2 for low cost and space saving, the adhesion between the toner and the photosensitive member 2 is large, so that the toner adheres to the photosensitive member 2. It's easy to do. Further, when the photoconductor 2 that does not contain a lubricant is used due to low cost, the adhesion between the toner and the photoconductor is large, and thus toner sticking to the photoconductor 2 is likely to occur. Furthermore, in order to reduce the running cost per printed sheet, when a toner not added with a lubricant is used, the adhesion between the toner and the photoconductor is large, so that the toner adheres to the photoconductor 2 easily. .

  Therefore, in the cleaning device of the present embodiment, the toner is applied to the toner so as to weaken the adhesion between the toner adhering on the photoconductor 2 and the photoconductor 2 on the downstream side of the cleaning blade 13 with respect to the surface movement direction of the photoconductor 2. Provide cleaning auxiliary means for contact. This cleaning assisting unit comes into contact with the toner that has passed through the cleaning blade, and weakens the adhesion between the toner and the photoreceptor 2. The toner whose adhesion to the photosensitive member 2 is weakened is easily removed by the cleaning blade 13 when it reaches the cleaning blade 13 again as the surface of the photosensitive member 2 moves. For this reason, it is possible to suppress the toner adhering to the photoconductor 2 from repeatedly passing through the cleaning blade 13 and firmly adhering to the photoconductor 2 to become a nucleus. Therefore, occurrence of toner sticking can be suppressed.

Among the toners whose adhesion to the photoreceptor 2 is weakened by the cleaning assisting means, some toners are removed from the photoreceptor 2 at the position of the cleaning assisting means. Thus, it may be removed from the photoreceptor 2 at the position of the cleaning assisting means.
In any case, the toner passing through the cleaning blade 13 and adhering to the photoconductor 2 is easily peeled off from the photoconductor 2 and is removed from the photoconductor 2 before it continues to pass through the cleaning blade 13. Toner sticking to the body 2 can be suppressed.

Hereinafter, it demonstrates in detail based on an Example.
<Example 1>
FIG. 20 is a schematic configuration diagram of the cleaning assisting unit of the first embodiment, where (a) is a cross-sectional view and (b) is a bottom view. In the first embodiment, a sheet-like cleaning auxiliary means 16 is provided as a cleaning auxiliary means. The base end of the sheet-like cleaning auxiliary means 16 is supported by the surface of the support member 14 opposite to the surface that supports the cleaning blade 13, and the tip is on the downstream side of the cleaning blade 13 and passes through the cleaning blade 13. Place it in contact with.

The sheet-like cleaning auxiliary means 16 can come into contact with the toner adhering to the photoreceptor 2 by a minute stick slip, and can weaken the adhesion between the toner and the photoreceptor 2. This sheet-like cleaning auxiliary means 16 has a simple structure and has an advantage of low cost.
Further, by adjusting the contact angle of the sheet-like cleaning auxiliary means 16 (see FIG. 21), selecting the shape and material, the ability to weaken the adhesion between the slip-through toner and the photosensitive member 2, and the sheet-like cleaning auxiliary means 16 The contact pressure to the photoreceptor 2 can be adjusted. Here, if the contact pressure to the photosensitive member 2 is too high, the hazard to the photosensitive member 2 is increased, and if the contact pressure is too low, the function as a cleaning assisting unit is insufficient. As shown in FIG. 21, when the sheet-like cleaning assisting means 16 is applied to the photoreceptor 2, the hazard to the photoreceptor 2 can be reduced.

  Further, the sheet-like cleaning auxiliary means 16 is provided integrally with the cleaning blade 13, and the sheet-like cleaning auxiliary means 16 is installed immediately after the cleaning blade 13. For this reason, the adhesion force between the toner and the photoconductor 2 can be weakened before the toner that has passed through the cleaning blade 13 adheres firmly to the photoconductor 2. Further, space saving and cost reduction can be achieved by providing the sheet-like cleaning auxiliary means 16 integrally with the cleaning blade 13 as compared with a configuration in which the sheet-like cleaning auxiliary means 16 is provided separately from the cleaning blade 13.

<Example 2>
FIGS. 22A and 22B are schematic configuration diagrams of a cleaning assisting unit according to the second embodiment, where FIG. 22A is a cross-sectional view and FIG. 22B is a bottom view. In the second embodiment, a cleaning-like cleaning auxiliary means 17 is provided as a cleaning auxiliary means. As shown in FIG. 22 (b), the sudder shape is a state in which the front end side of the sheet-like auxiliary means is divided in the longitudinal direction. The base end of the cleaning-like cleaning means 17 is supported by the surface of the support member 14 opposite to the surface that supports the cleaning blade 13, and the tip is downstream of the cleaning blade 13 and the toner that has passed through the cleaning blade 13. Place it in contact with.

  Compared with the sheet-like cleaning auxiliary means 16 of the first embodiment, the slip-like cleaning auxiliary means 17 has a finer stick-slip, so that the effect of weakening the adhesion between the slip-through toner and the photoreceptor 2 is enhanced. Further, in the sheet-like cleaning auxiliary means 16 of the first embodiment, when the sheet has a slight distortion in manufacturing, the contact pressure to the photosensitive member 2 locally increases, and the main scanning direction which is the width direction of the photosensitive member. As a result, there is a possibility that the behavior of the cleaning assisting means is uneven. On the other hand, the cleaning-like cleaning assisting means 17 according to the second embodiment is hardly affected by distortion, and the cleaning assisting means acts uniformly in the main scanning direction. Further, as in the first embodiment, the ability to weaken the adhesion between the slip-through toner and the photosensitive member 2 by adjusting the contact angle and selecting the shape and material, and the contact of the cleaning-type cleaning assisting means 17 with the photosensitive member 2. The pressure can be adjusted.

  Further, as in the first embodiment, since the sag-like cleaning auxiliary means 17 is provided integrally with the cleaning blade 13, the sag-like cleaning auxiliary means 17 can be installed immediately after the cleaning blade 13. For this reason, the adhesion force between the toner and the photoconductor 2 can be weakened before the toner that has passed through the cleaning blade 13 adheres firmly to the photoconductor 2. Further, as compared with the configuration in which the cleaning-like cleaning assisting means 17 is provided separately from the cleaning blade 13, by providing the cleaning-like cleaning assisting means 17 and the cleaning blade 13 integrally, space saving and cost reduction can be achieved. .

<Example 3>
FIG. 23 is a schematic configuration diagram of a cleaning assisting unit of Example 3, (a) is a cross-sectional view, and (b) is a bottom view. In the third embodiment, a brush-like cleaning auxiliary means 18 is provided as a cleaning auxiliary means. The brush-like cleaning auxiliary means 18 extends in a direction perpendicular to the surface of the photoreceptor 2 and is in contact with the photoreceptor 2 with a small area, and is a brush portion made of a plurality of fiber members, linear members, or needle-like members. 18a. The brush holding portion 18b that holds the brush portion 18a is supported by the surface of the support member 14 opposite to the surface that supports the cleaning blade 13. The tip of the brush-like member 18a is disposed downstream of the cleaning blade 13 so as to come into contact with the toner that has passed through the cleaning blade 13.

  As compared with the sheet-like cleaning auxiliary means 16 of the first embodiment and the slip-like cleaning auxiliary means 17 of the second embodiment, the brush-like cleaning auxiliary means 18 has a hazard to the photosensitive body 2 by making soft contact with the photosensitive body 2. Can be reduced. The brush-like cleaning auxiliary means 18 can adjust the ability to weaken the adhesion between the slip-through toner and the photoreceptor 2 by increasing the hardness and density of the fibers of the brush member 19a and adjusting the contact angle. Also, as in the first and second embodiments, the cleaning-like cleaning assisting means is provided integrally with the cleaning blade 13, so that the toner and the photosensitive member before the toner that has passed through the cleaning blade 13 firmly adheres to the photosensitive member. 2 can be weakened. In addition, space saving and cost reduction can be achieved.

<Example 4>
FIGS. 24A and 24B are schematic configuration diagrams of a cleaning assisting unit according to the fourth embodiment, in which FIG. 24A is a cross-sectional view and FIG. 24B is a bottom view. The cleaning assisting unit of Example 4 includes a toner contact member 19a having a surface extending along the surface moving direction of the photoreceptor 2, a contact member holding portion 19b, a compression spring 19c, and a spring holding member 19d. This is a surface cleaning auxiliary means 19. The toner contact member 19a is pressed against the photoreceptor 2 by a compression spring 19c through a contact member holding portion 19b. The spring holding member 19d that holds the compression spring 19c is supported by the surface of the support member 14 that is opposite to the surface that supports the cleaning blade 13. Then, the toner contact member 19 a is arranged on the downstream side of the cleaning blade 13 so as to contact the toner that has passed through the cleaning blade 13. As the toner contact member 19a, a block or sheet made of a highly flexible material such as felt or sponge is used to reduce the hazard to the photoreceptor 2.

  The surface cleaning auxiliary means 19 is pressed against the photoreceptor 2 by the compression spring 19c, and the toner contact member 19a extends along the surface movement direction of the photoreceptor 2, so that the contact area is wide. For this reason, the effect of weakening the adhesion between the slip-through toner and the photosensitive member 2 is high, and this is effective when the cleaning assisting means of Embodiments 1 to 3 are insufficient in the effect of weakening the adhesion between the slip-through toner and the photosensitive member 2. is there. Furthermore, by having a mechanism for adjusting the contact pressure between the toner contact member 19 a of the surface cleaning auxiliary means 19 and the photosensitive member 2, the ability to weaken the adhesion between the slip-through toner and the photosensitive member 2 can be adjusted. Further, as in the first to third embodiments, the cleaning-like cleaning assisting means is provided integrally with the cleaning blade 13, so that the toner and the photosensitive member before the toner that has passed through the cleaning blade 13 firmly adheres to the photoreceptor 2. The adhesion force with the body 2 can be weakened. In addition, space saving and cost reduction can be achieved.

<Example 5>
FIG. 25 is a cross-sectional view illustrating a schematic configuration of the cleaning assisting unit according to the fifth embodiment. In the fifth embodiment, instead of the toner contact member 19a of the surface cleaning auxiliary means 19 of the fourth embodiment, a brush-like toner contact member 20a extending along the surface moving direction of the photoreceptor 2 is used. This is a cleaning auxiliary means 20. By adopting such a configuration, it is possible to reduce the hazard to the photoconductor 2 as compared with the fourth embodiment while increasing the effect of weakening the adhesion between the slip-through toner and the photoconductor 2.

<Example 6>
FIGS. 26A to 26D are bottom views of the cleaning auxiliary means of the sixth embodiment. The cleaning assisting unit of Example 6 is configured such that the ability to weaken the adhesion between the slip-through toner and the photoreceptor 2 is different in the main scanning direction that is the width direction of the photoreceptor 2. This corresponds to a copier in which toner is likely to adhere to the photoconductor 2 intensively at a specific location in the main scanning direction, so that the cleaning auxiliary means and the photoconductor 2 are selectively contacted at the specific location in the main scanning direction. The pressure is increased to facilitate removal of the toner.
FIG. 26A shows a surface cleaning auxiliary unit 19 ′ according to the fourth embodiment, which has a structure in which the spring pressures of the compression springs 19c provided at two positions on the left and right sides in the main scanning direction are different.
FIG. 26B shows the brush-like cleaning auxiliary means 18 according to the third embodiment, which is a brush-like cleaning auxiliary means 18 ′ in which the brush fibers are locally elongated in the main scanning direction. Further, the brush fibers may be locally hardened in the main scanning direction.
FIG. 26 (c) shows the slidable cleaning auxiliary means 17 according to the second embodiment, which is a slidable cleaning auxiliary means 17 ′ having a configuration in which the tip is locally elongated in the main scanning direction. Further, the blur may be locally hardened in the main scanning direction.
FIG. 26D shows the sheet-like cleaning auxiliary means 16 according to the first exemplary embodiment, which is a sheet-like cleaning auxiliary means 16 ′ having a different length in the main scanning direction.

<Example 7>
FIG. 27 is a cross-sectional view illustrating a schematic configuration of the cleaning assisting unit according to the sixth embodiment. Example 6 is a cleaning auxiliary unit 21 using magnetic particles as a toner contact member. The cleaning auxiliary means 21 has a magnetic particle 21d accommodated in the case 21g, a rotatable nonmagnetic sleeve 21c containing the magnet roller 21b, and a supply roller 21e for supplying the magnetic particle 21d onto the sleeve 21c. doing. Furthermore, a doctor blade 21a that regulates the layer thickness of the magnetic particles 21d on the sleeve 21c and a doctor adjusting device 22 that can adjust the gap between the doctor blade 21c and the sleeve 21c are provided.

  The sleeve 21c carries the magnetic particles 21d supplied from the supply roller 21e by the magnetic force of the magnet roller 21b included therein, and forms a magnetic brush 21f made of the magnetic particles 21d on the surface. The magnetic brush 21f moves with the rotation of the sleeve 21c. After the layer thickness is regulated by the doctor blade 21a, the magnetic brush 21f reaches the area facing the photoconductor 2 and contacts the photoconductor 2. When the magnetic brush 21 f comes into contact with the photosensitive member 2, the toner on the photosensitive member 2 that has passed through the cleaning blade 13 is scraped off from the photosensitive member 2 or the adhesion force to the photosensitive member 2 is weakened. The toner whose adhesion to the photoconductor 2 is weakened reaches the cleaning blade 13 as the surface of the photoconductor 2 moves, and is scraped off by the cleaning blade 13. The cleaning assisting means 21 using magnetic particles has a high effect of weakening the adhesion between the slip-through toner and the photoreceptor 2 because the magnetic brush 21f is in contact with the photoreceptor 2, and the cleaning assisting means 21 itself is scratched as described above. Easy to be taken. Thereby, toner adhesion to the photoreceptor 2 can be suppressed.

  The doctor adjustment device 22 includes a drive mechanism (not shown) such as a solenoid and a motor, and slides the doctor blade 21a (arrow A in FIG. 28C) to connect the doctor blade 21a and the sleeve 21c. Adjust the gap. Thereby, the layer thickness of the magnetic brush 21f that contacts the photoconductor 2 in the region facing the photoconductor 2 can also be adjusted. By adjusting the layer thickness of the magnetic brush 21c, it is possible to adjust the ability to weaken the adhesion between the slip-through toner and the photoreceptor 2, and the hazard to the photoreceptor 2 by the magnetic brush 21f.

Each member which comprises Example 7 is demonstrated.
The magnetic particles 21d preferably have an average particle size of 20 μm or more and 50 μm or less. In the present embodiment, the magnetic particles 21d have a resin coating film on the magnetic core, and the resin coating film is a resin component obtained by crosslinking a thermoplastic resin such as acrylic and a melamine resin. The one containing a charge control agent was used.

  As the magnet roller 21b, a cylindrical member formed by mixing a magnetic powder in a resin and having a plurality of magnetic poles formed by applying a magnetizing process to the peripheral surface thereof was used. The magnet roller 21b of this embodiment has two poles, S poles and N poles, which are fixedly arranged. The diameter of the magnet roller 21b is 18 mm. The magnet roller 21b of the present embodiment is integrally formed as a whole. However, a magnet member separately formed for each magnetic pole may be disposed around the shaft. The integrally formed magnet roller 21b is preferably one in which magnetic powder is dispersed in a resin such as ethylene ethyl acrylate or nylon (registered trademark). The magnetic powder is preferably a rare earth magnet such as strontium ferrite, NdFeB, or SmFeN.

  The sleeve 21c is a non-magnetic hollow body, and the material thereof is preferably aluminum or stainless steel in view of workability, cost, and durability. It is preferable to randomly provide a large number of elliptical recesses on the outer peripheral surface of the sleeve 21c, for example, by forming a large number of random elliptical dents on the outer peripheral surface of the sleeve 21c. According to this configuration, it is possible to prevent the magnetic particles 21d from slipping without being able to follow the rotation of the developing sleeve 21c by making the dents on the surface of the sleeve 21c rough.

In the present embodiment, the pumping amount of the magnetic brush is set to 40.0 [mg / cm ² ] and PG is set to 0.3 [mm], but are not limited to these values.

<Example 8>
In the eighth embodiment, in the cleaning auxiliary unit 21 using magnetic particles as the toner contact member of the seventh embodiment, the toner contact member is divided into a plurality of parts in the main scanning direction, and each divided area is separated from the photoreceptor 2. It is configured so that it can be selectively contacted and separated.
FIGS. 28A and 28B are explanatory views of a cleaning assisting unit according to the eighth embodiment, in which FIG. 28A is a front view of the doctor blade 15, FIG. 28B is a top view of the doctor blade 15, and FIG. FIG. As shown in FIGS. 28A and 28B, the doctor blade 21a that regulates the layer thickness of the magnetic brush 21f conveyed to the region facing the photoconductor 2 is divided into a plurality of parts in the main scanning direction. Further, as shown in FIG. 28 (c), the doctor adjusting device 22 can individually adjust the gap with the sleeve 21c in each divided region of the doctor blade 21a.

  The doctor adjusting device 22 slide-drives each area of the divided doctor blade 21a (arrow A in FIG. 28C) by a drive mechanism such as a solenoid or a motor (not shown), and the doctor blade 21a, the sleeve 21c, Adjust the gap. By changing the gap between each divided area of the doctor blade 21 a and the sleeve 21 c by the doctor adjusting device 22, the doctor blade 22 is conveyed to the area facing the photoreceptor 2 corresponding to each divided area. The layer thickness of the magnetic brush 21f is selectively adjusted.

  For example, the doctor adjustment device 22 can select whether the distal end of the doctor blade 21a approaches or separates from the sleeve 21c in each divided region of the doctor blade 21a. When the cleaning auxiliary member 21 is not operated, the doctor adjusting device 22 brings the divided doctor blade 21a closer to the sleeve 21c. When the cleaning auxiliary member 21 is operated, the divided doctor blade 21a is selectively separated from the sleeve 21c only in a region where the magnetic brush 21f is brought into contact with the photosensitive member 2. In the region where the magnetic brush 21f is not in contact with the photosensitive member 2, the divided doctor blade 21a is kept close to the sleeve 21c. Thereby, the magnetic brush 21f can be selectively brought into contact with the areas of the photoreceptor 2 corresponding to the respective areas divided in the main scanning direction. The magnetic brush 21 f that selectively contacts the photoconductor 2 scrapes off the toner that has passed through the cleaning blade 13 from the photoconductor 2 or weakens the adhesion between the toner and the photoconductor 2. FIG. 27 shows an example in which the doctor blade 21a is divided into five parts in the main scanning direction. Correspondingly, the magnetic brush 21f as the toner contact member has five regions in the main scanning direction. The photosensitive member 2 can be selectively brought into contact with and separated from.

As described above, the reason why the magnetic brush 21f, which is the toner contact member of the cleaning auxiliary means 21, is selectively brought into contact with the main scanning direction of the photoreceptor 2 is as follows.
The toner adhering to the photoreceptor 2 by the toner that has passed through the cleaning blade 13 tends to occur in a region where the printing rate of the formed image is small and the toner input to the cleaning blade 13 is small. This is because when the toner input to the cleaning blade 13 is relatively large, the toner is not easily crushed because the toner continues to convect and move near the edge of the cleaning blade 13. On the other hand, when the toner input to the cleaning blade 13 is relatively small, the toner hardly moves near the edge portion of the cleaning blade 13 and is easily crushed. Therefore, the magnetic brush 21f, which is a toner contact member, is selectively brought into contact with a portion where the toner input to the cleaning blade 13 is small. In this way, by selectively bringing a part into contact with the main scanning direction, unnecessary wear of the photosensitive member 2 and the cleaning auxiliary means can be prevented, and the lifetime can be increased. As a result, the copying machine 500 can be reduced in time and cost.

FIG. 29 is a flowchart illustrating an example of control for selectively bringing the magnetic brush 21f into contact with an area where the toner input to the cleaning blade 13 is small. FIG. 30 is an explanatory diagram of a region where the photoreceptor abuts and separates. The toner contact member is divided into n regions with respect to the longitudinal direction of the photoreceptor 2, and the amount of toner input to the cleaning blade 13 is determined based on the force image printing rate in each region, and the magnetic brush 21f is selectively contacted. Is. FIG. 28 shows an example in which n = 5. Hereinafter, it demonstrates in detail based on a flow.
(STEP 1) The traveling distance of the photoreceptor 2 is counted.
(STEP 2) The average printing rate for each area is counted from the input image history.
(STEP 3) STEPs 1 and 2 are repeated until a specified travel distance (for example, 500 m) is reached.
(STEP 4) It is determined whether or not there is an area that does not reach a specified printing rate (for example, 5%).
(STEP 5) The magnetic brush of the cleaning assisting unit is brought into contact with a region that does not reach a specified printing rate (for example, 5%) for a specified traveling distance (for example, 500 m). When the specified travel distance is reached, the magnetic brush is separated.
(STEP 6) The print rate of all areas is reset to zero.
(STEP 7) The travel distance of the photosensitive member 2 is reset to zero.
By repeating such a flow, the magnetic brush 21f can be selectively brought into contact according to the amount of toner input to the cleaning blade 13. Thus, the toner can be effectively prevented from sticking to the tourist body, and unnecessary wear of the photosensitive member 2 and the cleaning auxiliary means can be prevented, thereby extending the life.

<Example 9>
FIGS. 31A and 31B are schematic configuration diagrams of the cleaning assisting unit according to the ninth embodiment, in which FIG. 31A is a cross-sectional view and FIG. 31B is a bottom view. In the ninth embodiment, in the surface cleaning auxiliary unit 23, the toner contact member is divided into a plurality of parts in the main scanning direction, and each of the divided areas can be selectively brought into contact with and separated from the photosensitive member 2. It is. The surface cleaning assisting means 23 has a toner contact member 23 a having a surface extending along the surface movement direction of the photoreceptor 2, a contact member holding portion 23 b, and a contact for bringing the toner contact member 23 a into contact with and away from the photoreceptor 2. It consists of a separating member 23c. The toner contact member 23a and the contact member holding portion 23b are divided into a plurality of parts in the main scanning direction, and contact / separation members 23c that contact and separate the respective areas from the photoreceptor 2 are provided for the divided areas. Yes. As the toner contact member 23a, a flexible nonwoven fabric is used, thereby reducing the hazard to the photoreceptor 2. The contact / separation member 23c includes a solenoid, a motor, and the like (not shown), and slides the contact member holding portion 23b (arrow A in the drawing) to contact each divided area of the toner contact member 23a with toner. The member 23a is brought into contact with the photoreceptor 2.

Each member which comprises Example 9 is demonstrated.
As the nonwoven fabric, a plain weave of polyester fiber, a thickness of 160 [μm], and a basis weight of 70 [g / m ² ] was used. The contact pressure of the toner contact member 23a to the photosensitive member 2 is preferably set as appropriate from the viewpoint of preventing the photosensitive member 2 from being worn and the toner (particles) from being deformed. It is preferable to set the value significantly lower than the contact pressure.

  In the surface cleaning auxiliary unit 23, the toner contact member 23 a contacts with a predetermined width in the surface moving direction of the photoreceptor 2. As a result, the toner that has passed through the cleaning blade 13 is scraped off from the photoreceptor 2 or the adhesion force with the photoreceptor 2 is weakened. The toner whose adhesion to the photoconductor 2 is weakened reaches the cleaning blade 13 as the surface of the photoconductor 2 moves, and is scraped off by the cleaning blade 13. Since the cleaning assisting means 23 using such a toner contact member 23a can widen the contact area with the photosensitive member 2, it has a high effect of weakening the adhesion between the slip-through toner and the photosensitive member 2, and as described above, the cleaning auxiliary means 23a. It is easily scraped off by the means 21 itself. Thereby, toner adhesion to the surface of the photoreceptor can be suppressed.

  Further, a plurality of regions (contact members A to E) of the divided toner contact member are arranged as shown in FIG. The contact members 23B and 23C are located downstream of the contact member A in the moving direction of the photoconductor surface, and extend with a position overlapping with one end of the contact member A as a base end. Similarly, the contact members D and E are also located downstream of the contact members B and C in the moving direction of the photosensitive member surface, and extend with the base end as a position overlapping with one end of the contact members B and C. With such an arrangement, the cleaning auxiliary means 23 can be brought into contact with the entire area downstream of the cleaning blade 13.

  In this planar cleaning auxiliary means 23, the contact member 23a is selectively brought into contact with the photosensitive member 2 in the main scanning direction, so that the toner fixing is efficiently suppressed and the image carrier and the cleaning auxiliary means are unnecessary. Abrasion can be prevented and a long life can be achieved.

What has been described above is an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
A latent image forming unit that forms an electrostatic latent image on an image carrier such as the photosensitive member 2 that moves on the surface, a developing unit that develops the electrostatic latent image on the image carrier, and a leading edge portion on the image carrier And a cleaning blade 13 that removes residual toner that has not been transferred from the image bearing member onto the transfer target member. In this image forming apparatus, a cleaning auxiliary means is provided on the downstream side of the cleaning blade with respect to the surface movement direction of the image carrier to contact the toner adhered on the image carrier and weaken the adhesion between the toner and the image carrier. . According to this, as described in the above embodiment, toner adhesion to the image carrier can be suppressed.

(Aspect B)
In (Aspect A), the developing means includes a developer carrying member such as a developing roller 42 having a groove on the surface, carries a one-component developer composed of a low-melting toner on the developer carrying member, and carries the developer. The developing device 4 transports the image forming body and the image carrier to a developing area facing each other in a non-contact manner, and performs development by forming a developing electric field in which alternating current is superimposed on direct current in the developing area. According to this, as described in the above embodiment, since the toner that has passed through the cleaning blade reaches the cleaning blade again without contacting the developing unit, it is effective in the image forming apparatus in which toner fixation is likely to occur. Toner sticking can be suppressed.

(Aspect C)
In (Aspect A) or (Aspect B), the member in contact with the toner is a sheet-like cleaning assisting means 16 in the form of a sheet. According to this, as described in the first embodiment, the adhesion force between the toner and the image carrier can be weakened by contacting the toner adhered on the image carrier by a minute stick slip. This cleaning auxiliary means has a merit that it has a simple configuration and is low in cost.

(Aspect D)
In (Aspect A) or (Aspect B), the member that contacts the toner is a sag-like cleaning auxiliary means 17 that is sag-like. According to this, as described in the second embodiment, since the stick slip becomes finer than that of the cleaning assisting unit in the first embodiment, the effect of weakening the adhesion between the slip-through toner and the image carrier is enhanced. Further, even if the member in contact with the toner has a minute distortion in manufacturing, there is an advantage that the cleaning assisting means acts uniformly in the width direction of the image carrier without being affected by the distortion.

(Aspect E)
In (Aspect A) or (Aspect B), the member in contact with the toner is a brush-like cleaning assisting means 18 having a brush shape. According to this, as described in the third embodiment, it is possible to reduce the hazard to the image carrier by making soft contact with the image carrier as compared with the cleaning auxiliary means of the first and second embodiments.

(Aspect F)
In (Aspect A) or (Aspect B), the member that contacts the toner is a planar cleaning auxiliary means 19 having a surface extending along the surface moving direction of the image carrier. According to this, as described in Examples 4 and 5 above, the contact area with the image carrier can be increased with respect to the surface movement direction of the image carrier, and the adhesion between the slip-through toner and the image carrier can be increased. Increases the effect of weakening. Examples 1 to 3 are effective when the effect of weakening the adhesion between the slip-through toner and the photoreceptor 2 is insufficient.

(Aspect G)
In (Aspect A) or (Aspect B), the member that contacts the toner is carried on a rotatable non-magnetic sleeve containing magnetic field generating means such as a magnet roller, and the layer thickness is regulated by the regulating member. It is a magnetic particle such as 21f. According to this, as described in the seventh embodiment, since the magnetic brush contacts the image carrier, the effect of weakening the adhesion between the slip-through toner and the photosensitive member 2 is enhanced. Examples 1 to 5 are effective when the effect of weakening the adhesion between the slip-through toner and the photoreceptor 2 is insufficient.

(Aspect H)
In (Aspect A), (Aspect B), (Aspect C), (Aspect D), (Aspect E), (Aspect F), or (Aspect G), the cleaning assisting means includes the toner in the width direction of the image carrier. The contact state is different. According to this, as described in the sixth embodiment, in correspondence with the image forming apparatus in which the toner fixing to the image carrier is likely to be concentrated on a specific portion in the width direction, it is selectively performed at the specific portion in the width direction. In addition, the contact pressure between the cleaning auxiliary means and the image carrier can be increased to easily remove the toner.

(Aspect I)
In (Aspect A), (Aspect B), (Aspect C), (Aspect D), (Aspect E), (Aspect F) or (Aspect G), the member in contact with the toner of the cleaning auxiliary means is an image carrier. Are divided into a plurality of regions in the width direction, and each of the divided regions can be selectively brought into contact with and separated from the image carrier. According to this, as described in the eighth and ninth embodiments, unnecessary wear of the image carrier and the cleaning auxiliary unit can be prevented by selectively bringing the cleaning auxiliary unit into contact with the width direction of the image carrier. , Life can be extended. As a result, the downtime and cost reduction of the image forming apparatus can be achieved.

(Aspect J)
In (Aspect I), the printing rate of the image formed on the image carrier is calculated for each of the divided regions of the member that contacts the toner, and the plurality of members that contact the toner based on the calculated printing rate. The contact / separation of each area divided into the carrier is controlled. According to this, as described in the eighth embodiment, the cleaning auxiliary means can be selectively brought into contact only with a region where toner input to the cleaning blade is small and toner sticking is likely to occur. For this reason, it is possible to efficiently suppress toner adhesion and to prevent unnecessary wear of the image carrier and the cleaning auxiliary means.

DESCRIPTION OF SYMBOLS 1 Process cartridge 2 Photoconductor 4 Developing device 5 Cleaning device 13 Cleaning blade 16 Sheet-like cleaning auxiliary means 17 Sludge-like cleaning auxiliary means 18 Brush-like cleaning auxiliary means 19 Planar cleaning auxiliary means 20 Wide brush-like cleaning auxiliary means 21 Magnetic brush Cleaning assist means 21f used Magnetic brush 42 Developing roller

JP-A-9-50217 JP 2008-065097 A JP 2009-109971 A

Claims (10)

A latent image forming unit that forms an electrostatic latent image on an image carrier that moves on the surface; a developing unit that develops the electrostatic latent image on the image carrier; and a tip ridge line portion is pressed against the image carrier. An image forming apparatus comprising a cleaning blade that removes toner remaining without being transferred from the image carrier onto the transfer member,
A cleaning assisting means is provided on the downstream side of the cleaning blade with respect to the surface movement direction of the image carrier to contact the toner adhered on the image carrier and weaken the adhesion between the toner and the image carrier. An image forming apparatus.   2. The image forming apparatus according to claim 1, wherein the developing unit includes a developer carrying member having a groove on a surface thereof, carrying a one-component developer made of a low melting point toner on the developer carrying member, and the developer. An image forming apparatus characterized in that a carrier and the image carrier are transported to a development area facing each other in a non-contact manner, and development is performed by forming a development electric field in which alternating current is superimposed on direct current in the development area.   3. The image forming apparatus according to claim 1, wherein the member of the cleaning assisting unit that contacts the toner is in a sheet form.   3. The image forming apparatus according to claim 1, wherein the member of the cleaning assisting unit that contacts the toner has a sled shape.   3. The image forming apparatus according to claim 1, wherein the member of the cleaning auxiliary unit that contacts the toner has a brush shape.   3. The image forming apparatus according to claim 1, wherein the member of the cleaning auxiliary unit that contacts the toner has a surface extending along a surface movement direction of the image carrier.   3. The image forming apparatus according to claim 1, wherein the member of the cleaning auxiliary means that contacts the toner is carried on a rotatable non-magnetic sleeve containing the magnetic field generating means, and the layer thickness is regulated by the regulating member. An image forming apparatus comprising particles.   8. The image forming apparatus according to claim 1, wherein the cleaning assisting unit is configured such that a contact state with the toner is different in a width direction of the image carrier. An image forming apparatus.   8. The image forming apparatus according to claim 1, wherein the member that contacts the toner of the cleaning auxiliary unit is divided into a plurality of regions in the width direction of the image carrier. An image forming apparatus, wherein each of the plurality of divided areas is provided so as to be selectively contactable and separable with respect to the image carrier.   10. The image forming apparatus according to claim 9, wherein a printing rate of an image formed on the image carrier is calculated for each of a plurality of divided regions of the member that contacts the toner, and the toner is contacted based on the printing rate. An image forming apparatus that controls contact / separation of each region divided into a plurality of members to the image carrier.

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