JP2014056104A - Developing device, image forming apparatus, and developing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of adhesion of toner at a contact part between a developer carrier and a developer thickness regulating member to prevent disturbance of a toner thin layer on the developer carrier.SOLUTION: A developing device includes: a cloud roller 13d that conveys a developer to a photoreceptor drum 11; odd number-side electrodes 21 and even number-side electrodes 22 that are provided to the cloud roller 13d, the even number-side electrodes 22 being provided with a surface protective layer 24 that is an insulator between the odd number-side electrodes 21; a driving circuit that applies an alternating voltage in which a potential difference between the odd number-side electrodes 21 and the even number-side electrodes 22 is temporally reversed to make the developer in a cloud state; and a toner thickness regulating member 13e that forms a predetermined gap with the cloud roller 13d to regulate a thickness of the developer remaining on the cloud roller 13d after the development. The driving circuit has increased the number of reversion per predetermined time of the alternating voltage applied during the interim of actual developments, twice or more that during the development.

Description

  The present invention relates to a developing device, an image forming apparatus, and a developing method, and more specifically, a developing device that develops by developing a cloud of a developer, an image forming device including the developing device, and development performed by the developing device Regarding the method.

  Conventionally, as a developing device of this type, a toner that has been hopped on the surface of a toner carrier such as a toner carrying substrate is not used for development, but is used for development. Are known.

  For example, a developing device described in JP-A-3-21967 (Patent Document 1) includes a cylindrical toner carrier having a plurality of electrodes arranged at a predetermined pitch in the circumferential direction. These electrodes are formed by repeatedly arranging electrode pairs composed of two electrodes adjacent to each other. An alternating electric field is formed between the two electrodes in each electrode pair. Then, the hopping that the toner that has been located on one electrode in the electrode pair floats and landes on the other electrode, or floats on the other electrode and landes on one electrode. Do. Then, while repeating the hopping in this way, the cylindrical toner carrier is transported to the developing region by the surface movement accompanying the rotational driving. In the developing region, the toner that has floated to the vicinity of the latent image on the latent image carrier is attracted to the electric field by the latent image and does not descend toward the electrode of the toner carrier, and adheres to the latent image.

  In such a configuration, not the toner adsorbed on the developing roller or the magnetic carrier but the toner that does not exhibit the adsorbing force by hopping is used for the development. As a result, low-potential development that cannot be realized by the conventional one-component development method or two-component development method can be realized. For example, toner can be selectively attached to an electrostatic latent image having a potential difference of only a few tens [V] with respect to surrounding non-image portions.

  However, the developing device described in Patent Document 1 has a problem that the toner adheres to the contact portion between the toner carrier and the toner regulating member, and the toner thin layer on the toner carrier is disturbed.

  On the other hand, Japanese Patent Application Laid-Open No. 2002-207355 (Patent Document 2) discloses a developing device having a developer carrying member and a layer thickness regulating member for regulating the layer thickness of a one-component developer carried on the developer carrying member. A developer having a predetermined polarity between the layer thickness regulating member and the developer carrying member, wherein at least the developer carrying member contact portion of the layer thickness regulating member is made of an insulating material. A technique characterized by providing a voltage applying means for applying a voltage for forming an alternating electric field on which a direct current component for forming an electric field directed to the developer carrier side from the layer thickness regulating member side is superimposed. Have been described.

  With this configuration, the toner reciprocates at the facing portion between the layer regulating member and the developer carrier to prevent aggregation, and a uniform charge amount is sufficient on the developer carrier. The toner layer can be stably formed over a long period of time, and toner scattering outside the developing device can be prevented.

  In the technique described in Patent Document 2, the developer is reciprocated by an external oscillating electric field in the gap between the developer carrier and the developer thickness regulating member to prevent agglomeration. A stable and uniform developer layer can be formed, and toner sticking or aggregation in Patent Document 1 can be prevented. However, what can be prevented is temporary. That is, even if the toner aggregation can be eliminated temporarily, the regulated toner stays in the wedge formed by the regulating member and the developer carrier (developing roller), and the developer carrier is driven. During this process, it is considered that the toner continues to be stressed and eventually adheres, so that the toner adheres at the contact portion between the developer carrier and the regulating member, and the toner thin layer on the developer carrier The problem of disturbance has not been solved.

  Therefore, the problem to be solved by the present invention is to suppress the occurrence of toner fixation at the contact portion between the developer carrying member and the developer thickness regulating member, and to prevent the toner thin layer on the developer carrying member from being disturbed. There is.

  In order to solve the above problems, the present invention relates to a developer carrier that transports a developer to an image carrier, a first electrode provided on the developer carrier, and the first electrode. A second electrode provided through an insulator, a voltage applying unit that applies an alternating voltage in which a potential difference between the first electrode and the second electrode is temporally reversed, and converts the developer into a cloud; A predetermined gap is formed between the developer carrying member and a regulating member that regulates the layer thickness of the developer remaining on the developer carrying member after development, and is applied between the realized images. The developing device is characterized in that the number of inversions of the alternating voltage per fixed time is twice or more that during development.

  According to the present invention, it is possible to suppress the occurrence of toner fixation at the contact portion between the developer carrying member and the developer thickness regulating member, and to prevent the toner thin layer on the developer carrying member from being disturbed.

1 is a diagram illustrating a configuration of an image forming unit including a developing device of an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the internal structure of the process cartridge currently used by the image creation part of FIG. FIG. 3 is a diagram showing an internal configuration of a developing device in the process cartridge of FIG. 2. FIG. 4 is a waveform diagram showing a state of application of alternating voltage in Example 1. 6 is a waveform diagram showing a state of application of alternating voltage in a comparative example of Example 1. FIG. It is a figure which shows the measurement result which measured the time change of the number of stripes on the surface of a cloud roller when a developing device was stirred for 120 minutes by the print job which prints one page by one job. 6 is a waveform diagram showing a state of application of an alternating voltage in Example 3. FIG. FIG. 10 is a waveform diagram showing states of an applied voltage to a cloud roller and an applied voltage to a toner layer thickness regulating member in Example 4. It is a perspective view which shows schematic structure of a cloud roller. It is the figure which crossed the cloud roller in the direction orthogonal to a longitudinal direction, developed, and showed the electrode part. It is a figure which expands and shows the electrode part of a cloud roller in plane. It is a figure which shows the drive waveform of the antiphase applied to a two-phase electrode.

  The present invention relates to a developing device that uses toner hopped on the surface of a developer carrying member for development, the frequency of an alternating electric field during which the developing device develops a latent image, in other words, a portion corresponding to the space between papers. The frequency of the alternating electric field is set to be equal to or higher than the frequency when the latent image is actually developed.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of an image forming unit including a developing device of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus according to the present embodiment is a so-called indirect transfer type tandem type full-color image forming apparatus that forms a toner image of each color on an intermediate transfer member, and the image forming apparatus or the image forming unit itself of this configuration. Is conventionally known. Therefore, the configuration will be briefly described. The image forming unit 1 includes magenta (M), cyan (C), yellow (Y), and black (Bk) image forming stations 10M, 10C, 10Y, and 10Bk. And an intermediate transfer belt 17 as an intermediate transfer member.

  The image forming stations 10 for the respective colors are arranged in a straight line (hereinafter, when the colors are common, M, C, Y, and Bk indicating the colors are omitted). Each image forming station 10 basically includes a photosensitive drum 11, a charging device 12, a developing device 13, a primary transfer device (primary transfer roller) 14, a cleaning device 15, and a charge removal device 16. Of the image forming stations 10, the photosensitive drum 11, the charging device 12, the developing device 13, the cleaning device 15, and the charge removal device 16 are process cartridges 10 CR configured to be replaceable as one unit, and are primary. The transfer device 14 is located at a position facing the photosensitive drum 11 of the process cartridge 10CR with the intermediate transfer belt 17 interposed therebetween. The intermediate transfer belt 17 is stretched between a driving roller 18, a driven roller 19, and four primary transfer rollers 14, and is rotationally driven by a driving unit (not shown).

  When forming an image, first, the charging device 12 uniformly charges the photosensitive layer on the surface of the photosensitive drum 11. The charged photosensitive drum 11 is exposed by a light beam modulated with magenta image data by a writing device as exposure means (not shown), and an electrostatic latent image to be developed with magenta is formed on the photosensitive drum 11. The This electrostatic latent image is developed by a developing device (magenta) 13M to become a magenta toner image (visualized image). Next, the image is transferred onto the intermediate transfer belt 17 by the primary transfer device 14.

  The development and transfer operations are sequentially executed at 10C, 10Y, and 10Bk at cyan, yellow, and black image forming stations, and four color images are superimposed on the intermediate transfer belt 17 to form a full color image. Residual toner on the photosensitive drum 11 is cleaned by the cleaning device 15, and the surface of the photosensitive drum 11 is neutralized by the neutralization device 16 to return to the initial state, and is newly charged in the next step.

On the other hand, a recording medium such as recording paper is fed from a paper feeding device (not shown). This recording medium is conveyed to a nip portion between a secondary transfer device (secondary transfer roller) as a transfer means to which a transfer bias is applied from a power source and the intermediate transfer belt 17, and the full color on the intermediate transfer belt by the secondary transfer device. The image is transferred to a recording medium. The recording medium on which the full color image is transferred is fixed by the fixing device (not shown) and discharged to the outside. In the intermediate transfer belt, residual toner and the like are removed by a cleaner as a cleaning unit after the full-color image is transferred.
FIG. 2 is a view showing a process cartridge used in the image forming unit 1 shown in FIG. 1, and FIG. 3 is a view showing a developing device in the process cartridge.

  In FIG. 2, the image forming station 10 includes the photosensitive drum 11, the charging device 12, the developing device 13, the cleaning device 15, and the charge eliminating device 16 as described above. As shown in FIG. 3, the developing device 13 includes a toner storage portion 13a, a stirring paddle 13b, a supply (collection) roller 13c, a cloud roller 13d, and a toner layer thickness regulating member 13e. Since the configuration of the developing device 13 is known, detailed description thereof will be omitted here, and the toner behavior in the developing device 13 will be described.

  In addition, toner hopped on the surface of the toner carrier (cloud roller) is used for development, but when viewed microscopically, the toner that is “hopping” is observed in a “cloud” shape when viewed macroscopically, This is called the “cloud state” or “flare state” of the toner. Therefore, in this specification, “flare” is also described in a unified manner using the term “cloud”.

  First, the toner stored in the toner storage unit 13a is conveyed to the supply roller 13c by the stirring paddle 13b. In the configuration of the developing device 13 in FIG. 2, the supply roller 13c also functions as a collection roller by rotating the supply roller 13c in the counter direction with the cloud roller 13d. Therefore, here, it is referred to as a supply (collection) roller. Of course, the supply member and the recovery member may be independent.

  When toner is supplied from the supply roller 13c to the cloud roller 13d, the toner is charged by friction between the cloud roller 13d and the supply roller 13c. The charged toner performs a hopping motion in accordance with an electric field that periodically changes between the two-phase electrodes inside the cloud roller 13d. Then, when the cloud roller 13d itself is rotated, the toner adhesion amount on the surface of the cloud roller 13 is regulated through the toner layer thickness regulating member 13e. Thereafter, the toner is conveyed to a region facing the photosensitive drum 11, and the electrostatic latent image on the photosensitive drum 11 is developed in a non-contact manner with toner.

  On the other hand, the toner that has not contributed to development passes through the development area. The toner after passing is collected by a collection roller 13c (in this example, the collection function and the supply function are integrated, and thus the same as the above-described supply roller 13c), and is temporarily returned to the toner storage unit 13a. Since the toner on the cloud roller 13d is hopped, the adhesion between the cloud roller 13d and the toner is small, and is easily collected by the collection roller 13c. By repeating such a series of processes, a state where the toner is always hopping is formed on the cloud roller 13d.

  The above is the outline of the configuration and operation of the image forming unit 1 and the developing device 12 that have been conventionally performed, and is a premise of the present embodiment. Hereinafter, it will be described in more detail with reference to examples.

  FIG. 4 is a waveform diagram showing a state where an alternating voltage is applied in the first embodiment.

In the first embodiment, in the developing device 13 of FIG. 3, the cloud roller 13d is stopped between sheets, and an alternating voltage having a frequency twice or more that at the time of image formation is applied to the electrode on the cloud roller 13d. Specific application conditions are, for example,
Average value V0: -300V
Peak to peak voltage Vpp: 500V
Frequency f (Duty) during image formation: 700 Hz (50%)
Frequency f ′ (Duty) during paper interval: 1500 Hz (50%)
It is. Note that the sheet interval here corresponds to the interval between the preceding sheet and the succeeding sheet of the recording sheet conveyed from the sheet feeding device, but when viewed on the photosensitive drum 11, the preceding image to be formed and the following sheet are detected. This corresponds to the image interval of the images.

  If the frequency of the alternating voltage at the time of the sheet interval is increased as in the application condition, the toner is released from the surface of the cloud roller 13d or moves irregularly on the surface of the cloud roller 13d. For this reason, the toner staying in the groove formed by the contact between the cloud roller 13d and the toner layer thickness regulating member 13e is removed. As a result, the toner adheres to the toner layer thickness regulating member 13e and the toner thin film on the cloud roller 13d is thinned. Layer disturbance can be prevented.

  FIG. 5 is a waveform diagram showing a state of application of alternating voltage in the comparative example of Example 1. In this comparative example, the frequency f ′ at the time between sheets was fixed to 700 Hz, which is the frequency f at the time of image formation. If the frequency between the sheets is constant, the toner regulated at the contact portion between the cloud roller 13d and the toner layer thickness regulating member 13e receives a force due to the rotation of the cloud roller 13d. As a result, the toner continues to stay in a groove formed by the cloud roller 13d and the toner layer thickness regulating member 13e. The staying toner aggregates as it continues to receive friction at the contact portion for a certain time, and adheres or adheres firmly to the toner layer thickness regulating member 13e. When fixed in this manner, the fixed toner comes into contact with the roller surface layer, thereby causing uneven density in the longitudinal direction and vertical white stripes in the toner thin layer on the cloud roller 13d.

  FIG. 6 is a diagram illustrating measurement results obtained by measuring a time change in the number of streaks on the surface of the cloud roller 13d when the developing device 13 is stirred for 120 minutes in a print job (1p / J) for printing one page in one job. It is. As can be seen from the figure, when the frequency is constant at 700 Hz, the streaks on the surface of the cloud roller 13d increased with time. On the other hand, when the frequency f 'between the sheets was 1500 Hz, streaks were not generated after 2 hours of air stirring.

  Note that this embodiment is also effective in continuous printing that is not 1p / J and in which the driving does not stop between sheets, but the effect of the airflow generated by the rotational drive is pushed back to the contact portion, so that the effect is less than in the case of stopping. Decrease.

  The second embodiment is an example in which the cloud roller 13d is rotated in the opposite direction to that during the development with respect to the first embodiment. That is, in Example 2, the cloud roller 13d was rotated in the opposite direction to that during development while an alternating voltage having a frequency twice or more that during image formation was applied to the electrode on the cloud roller 13d between the sheets. Specifically, after stopping the cloud roller 13d between papers, it was rotated 20 degrees in the reverse direction at the same linear speed as that during driving. The applied voltage and frequency are the same as in the first embodiment.

  When the frequency of the alternating voltage during the sheet interval is increased under the application conditions of the first embodiment, the toner is released from the surface of the cloud roller 13d or moves irregularly on the surface of the cloud roller 13d. Therefore, in the second embodiment, when the toner is separated from the surface of the cloud roller 13 or moves irregularly on the surface of the cloud roller 13d, the cloud roller 13d is reversely rotated. Thereby, the toner staying in the groove formed by the contact between the cloud roller 13 and the toner layer thickness regulating member 13e is efficiently removed. As a result, it is possible to prevent toner adhesion to the toner layer thickness regulating member 13e and disturbance of the toner thin layer on the cloud roller 13d, and a good image can be obtained.

  Example 3 is an example in which the peak-to-peak voltage Vpp of the alternating voltage applied between the sheets is set to an alternating voltage larger than that at the time of image formation. That is, in Example 3, an alternating voltage having a frequency twice or more that at the time of image formation and a peak-to-peak value larger than that at the time of image formation was applied to the electrodes on the cloud roller 13d between the sheets.

  FIG. 7 is a waveform diagram showing an alternating voltage application state in the third embodiment. As can be seen from the figure, specifically, the peak-to-peak voltage Vpp was set to 600 V, and the rest was the same as in Example 1.

  As shown in FIG. 7, as the peak-to-peak voltage Vpp increases, the electric field strength increases. As a result, the initial speed of toner hopping is increased. As a result, when the frequency of the alternating voltage between the sheets is high, the toner is released from the surface of the cloud roller 13d, or the speed at which the surface of the cloud roller 13d moves irregularly increases. By this increase in speed, the toner staying in the vicinity of the contact portion of the toner layer thickness regulating member 13e with the cloud roller 13d is effectively removed from the vicinity. As a result, it is possible to prevent toner adhesion to the toner layer thickness regulating member 13e and disturbance of the toner thin layer on the cloud roller 13d, and a good image can be obtained.

  In the fourth embodiment, the average voltage of the cloud roller 13d is applied to the toner layer thickness regulating member 13e while an alternating voltage having a frequency twice or more that during image formation is applied to the electrode on the cloud roller 13d between the paper sheets. The voltage was applied so as to be +100 V with respect to the voltage V0. FIG. 8 is a waveform diagram showing the state of the applied voltage to the cloud roller 13d and the applied voltage to the toner layer thickness regulating member 13e at this time. Specifically, the voltage Vbl of the toner layer thickness regulating member 13e is set to −200V, and other than that is the same as in the first embodiment.

  As shown in FIG. 8, when the voltage applied to the toner layer thickness regulating member 13e is set to the positive side of the average voltage V0 applied to the cloud roller 13d, the toner when the frequency of the alternating voltage between the sheets is high is used. Is released from the surface of the cloud roller 13d, or the toner moving irregularly on the surface of the cloud roller 13d is attracted to the toner layer thickness regulating member 13e. Therefore, the toner staying in the vicinity of the cloud layer 13d of the toner layer thickness regulating member 13e is effectively removed from the vicinity. As a result, it is possible to prevent toner adhesion to the toner layer thickness regulating member 13e and disturbance of the toner thin layer on the cloud roller 13d, and a good image can be obtained. Therefore, toner adhesion to the regulating member and disturbance of the toner thin layer on the cloud roller can be prevented, and a good image can be obtained.

  Here, the cloud development performed by the cloud roller 13d will be described.

  FIG. 9 is a perspective view showing a schematic configuration of the cloud roller 13d, and FIG. 10 is a diagram showing a cross section of the cloud roller 13d in a direction perpendicular to the longitudinal direction and developing the electrode portion. As shown in FIG. 10, a plurality of electrodes 21 and 22 are arranged in parallel at a predetermined interval on a support substrate 23, and a surface protective layer 24 formed of an inorganic or organic insulating material is laminated thereon. . 21 represents an odd-numbered electrode (for example, the first electrode), 22 represents an even-numbered electrode (for example, the second electrode), and the odd-numbered electrode 21 has an A-phase voltage 27A and an even-numbered electrode. A B-phase voltage 27 </ b> B is applied to 22.

  In FIG. 10, lines 25 and 26 extending from the electrodes 21 and 22 represent conductive lines for applying a voltage to the electrodes 21 and 22, respectively. Of the overlapping portions of the lines 25 and 26, only the portions indicated by black circles are electrically connected, and the other portions are electrically insulated. Two-phase driving voltages 27A and 27B applied to the electrodes 21 and 22 are supplied from a power source (not shown) on the main body side. Similarly, the drive voltage is set to the application condition by a drive circuit (not shown) and applied as drive voltages 27A and 27B.

  The drive circuit includes a CPU. The CPU includes a control unit and a calculation unit. The control unit controls the flow of instruction interpretation and program control, and the calculation unit executes calculation. The program is stored in a memory (not shown), an instruction to be executed (a certain numerical value or a sequence of numerical values) is taken out from the memory in which the program is placed, and the program is executed.

  FIG. 11 is a plan view showing the electrode portion of the cloud roller 13d. This planarly expanded electrode portion is a so-called electrode pattern 20. As shown in FIGS. 9 to 11, the cloud roller 13d has two-phase electrodes 21 and 22 that generate an electric field for hopping toner, and includes an even-numbered electrode 22 group and an odd-numbered electrode 21 group. As an example, a driving waveform having an opposite phase as shown in FIG. 12A or 12B is applied from a driving circuit (not shown), and a time-periodic potential difference is formed between the two-phase electrodes 21 and 22.

  The cloud roller 13d is supported on a bearing (not shown) of the developing device 13 by a rotating shaft 28, and is driven to rotate by a driving source (not shown). An odd numbered electrode 21 is connected to one of the rotating shafts 28, and an even numbered electrode 22 is connected to the other of the rotating shafts 28. The CPU also executes rotation drive control of the cloud roller 13d.

As the support substrate 23 of the cloud roller 13d, a substrate made of an insulating material such as a resin or a substrate made of a conductive material such as SUS and an insulating film such as SiO ₂ can be used. For the electrode, a conductive material such as Al, Cu, or Ni—Cr is formed on the support substrate in a thickness of 0.1 to 10 μm, preferably 0.5 to 2.0 μm, and this is required by a photolithographic technique or the like. It is formed by patterning into an electrode shape.

The electrode width L and the electrode interval R on the cloud roller 13d for toner hopping greatly affect the toner hopping efficiency. The electrode pitch P is
P = R + L
It is represented by The toner between the electrodes 21 and 22 moves on the surface of the support substrate 23 to an adjacent electrode by a substantially horizontal electric field. On the other hand, the toner on the electrodes 21 and 22 is given an initial velocity having at least a component in the vertical direction, so that most of the toner flies away from the support substrate surface. In particular, since the toner near the electrode end surface moves over the adjacent electrode, when the electrode width L is wide, the number of toners on the electrode increases, and the toner having a large moving distance increases. However, if the electrode width L is too wide, the electric field strength in the vicinity of the center of the electrode is lowered, so that the toner adheres to the electrode and the hopping efficiency is lowered. The hopping efficiency is the ratio of toner that hops when a hopping electric field is applied.

  In view of the above, the present inventors have intensively researched and found that there is an appropriate electrode width for efficiently hopping toner at a low voltage.

  The electrode interval R determines the electric field strength between the electrodes 21 and 22 from the relationship between the distance and the applied voltage. The smaller the interval R is, the stronger the electric field strength is, and it is easy to obtain the initial hopping speed. However, for the toner that moves from the electrode 21 (22 to the electrode 22 (21), the moving distance of one time is shortened, and the hopping time is shortened unless the drive frequency is increased. As a result of intensive research on the toner, the time for which the toner lands on the electrodes 21 and 22 has been increased, and as a result, the present inventors have an appropriate electrode interval for efficiently transporting and hopping the toner at a low voltage. I found out.

  Furthermore, the inventors of the present invention also influence the electric field strength of the surfaces of the electrodes 21 and 22 by the thickness of the surface protective layer 24 covering the surfaces of the electrodes 21 and 22, and particularly the influence of the vertical component on the electric field lines. Also found to determine the efficiency of hopping.

  Thus, it can be seen that efficient hopping can be performed at a low voltage by appropriately setting the relationship between the electrode width L, the electrode interval R, and the surface protective layer thickness of the cloud roller 13d.

Therefore, in the present embodiment, the electrode width L shown in FIG. 10 is 1 to 20 times the average toner particle size, and the electrode interval R is also 1 to 20 times the average toner particle size. For example, SiO ₂ , BaTiO ₂ , TiO ₂ , TiO ₄ , SiON, BN, TiN, Ta ₂ O _5, or the like can be applied to the surface protective layer 24, and the thickness is 0.5 to 30 μm. Further, an organic material such as polycarbonate may be coated on SiO ₂ or the like. It is also possible to select zirconia or a material generally used as a coating material for a carrier of a two-component developer, for example, a silicone resin. The surface protective layer 24 is appropriately selected from the relationship between the insulating property, durability, the manufacturing method of the cloud roller 13d itself, and the charge train with the toner to be used.

  Furthermore, when the developing device 13 according to the present embodiment is used in the image forming unit 1 of the image forming apparatus shown in FIG. 1, the surface of the cloud roller 13d is a long, large area having an A4 length of 21 cm or a width of 30 cm or more. Therefore, it is necessary to form a fine pattern.

In order to form a fine pattern on the surface of such a long and large area cloud roller 13d,
・ Forming a flexible electrode pattern and winding it around a support drum ・ Method of patterning electrode material on a polyimide base film ・ Screen printing using conductive ink, inkjet printing, plating There is a method of removing the non-electrode portion of the processed electrode by laser processing.

  A method of forming a flexible electrode pattern and winding it around a support drum is as follows.

  For example, a polyimide (PI) base film (thickness 20 to 100 μm) is used as a substrate having flexible fine pitch thin layer electrodes. Using this polyimide (PI) base film as a base material (support substrate 23), Cu, Al, Ni—Cr, etc. having a thickness of 0.1 to 0.3 μm are formed thereon by vapor deposition. If it is 30-60 cm in width, it can be manufactured by a roll-to-roll apparatus, and mass productivity is greatly increased. The common bus line simultaneously forms electrodes having a width of about 1 to 5 mm.

  Specifically, a method such as a sputtering method, an ion plating method, a CVD method, or an ion beam method can be applied to the vapor deposition method. For example, when an electrode is formed by sputtering, a Cr film may be interposed in order to improve adhesion with polyimide, and adhesion can also be improved by plasma treatment or primer treatment.

  Further, as a method other than the vapor deposition method, a thin layer electrode can be formed also by an electrodeposition method. In this case, an electrode is first formed on the polyimide substrate by electroless plating. A base electrode can be formed by sequentially immersing in Sn chloride, Pd chloride, and Ni chloride, and then electroplating can be performed in a Ni electrolyte solution to produce a Ni film of 1 to 3 μm in a roll-to-roll manner.

  Then, electrodes 21 and 22 are formed on these thin film electrodes by resist coating, patterning, and etching. In this case, if the electrode is a thin layer electrode having a thickness of 0.1 to 3 μm, a fine pattern electrode having a width of 5 μm to several tens of μm or an interval can be accurately formed by photolithography and etching.

Then, the thickness of 0.5~2μm the _{SiO 2,} BaTiO 2, TiO 2 or the like as a surface protective layer 24 is formed by sputtering or the like. Alternatively, polyimide is applied as a surface protective layer to a thickness of 2 to 5 μm with a roll coater or other coating device, and baked to finish. When troubles occur with polyimide as it is, SiO ₂ and other inorganic films may be formed on the outermost surface by sputtering or the like to a thickness of 0.1 to 0.5 μm. Further, an organic material such as polycarbonate may be coated on SiO ₂ or the like. It is also possible to select zirconia or a material generally used as a coating material for a carrier of a two-component developer, for example, a silicone resin.

  By configuring such a flexible substrate, the cloud roller 13d according to the present embodiment can be manufactured by being attached to a cylindrical drum or by partially forming a curved surface.

  In a method of patterning an electrode material on a polyimide base film as a base material, a polyimide base film (thickness 20 to 100 μm) is used as a base material (supporting substrate 11), and an electrode material is formed thereon, for example, as a thickness. 10 to 20 μm of Cu, SUS or the like is used. In this case, conversely, polyimide is applied on a metal material with a roll coater by 20 to 100 μm and baked. Thereafter, the metal material is patterned into the shape of the electrodes 21 and 22 by photolithography and etching to form the electrode pattern 22, and polyimide is coated on the surfaces of the electrodes 21 and 22 as the protective layer 13. In this case, if there are irregularities according to the thickness of the metal material electrode of 10 to 20 μm, it is flattened and completed.

  The planarization is performed, for example, by spin-coating a polyimide material or polyurethane material having a viscosity of 50 to 10,000 cps, more preferably 100 to 300 cps, and leaving it to stand. In this case, the substrate unevenness is smoothed by the surface tension of the material while being left, and the outermost surface of the conveying member is flattened.

  Furthermore, as another example of increasing the strength of the flexible substrate, an SUS or Al base material having a thickness of 20 to 30 μm is used as the base material, and an insulating layer (insulation between the electrode and the base material) is formed on the surface thereof. ), A diluted polyimide material of about 5 μm is coated with a roll coater. The polyimide is then pre-baked at 150 ° C. for 30 minutes and post-baked at 350 ° C. for 60 minutes to form a thin-layer polyimide film.

Thereafter, after performing plasma treatment and primer treatment for improving adhesion, Ni-Cr is deposited as a thin electrode layer in a thickness of 0.1 to 0.2 μm, and the fine pattern of several tens of μm is formed by photolithography and etching. Electrodes 21 and 22 (electrode pattern 20) are formed. Furthermore, a flexible transport member can be obtained by forming the surface protective layer 13 such as SiO ₂ , BaTiO ₂ , or TiO _{2 on} the surface to a thickness of about 0.5 to 1 μm by sputtering. Further, an organic material such as polycarbonate may be coated on SiO ₂ or the like. It is also possible to select zirconia or a material generally used as a coating material for a carrier of a two-component developer, for example, a silicone resin.

  Further, as described above, a fine pattern can be formed by a method such as screen printing using conductive ink, ink jet printing, or removal of non-electrode portions of the plated electrode by laser processing. At this time, the surface protective layer 24 can also be formed by the above-described method, but is not limited to the above-described method, and a known method can also be applied.

  As described above, according to the present embodiment, the following effects can be obtained.

1) A cloud roller 13d that conveys developer to the photosensitive drum 11, an odd-numbered electrode 21 provided on the cloud roller 13d, and a surface protection layer 24 that is an insulator with respect to the odd-numbered electrode 21. In addition, an even voltage is applied between the even-numbered electrode 22 and an alternating voltage in which the potential difference between the odd-numbered electrode 21 and the even-numbered electrode 22 is reversed in time to set the developer in the cloud and the cloud roller 13d in advance. And a toner layer thickness regulating member 13e that regulates the layer thickness of the developer remaining on the cloud roller 13d after development, and the drive circuit has a constant alternating voltage applied between realized images. The number of reversals per hour was set to be twice or more that during development. As a result, a phenomenon occurs in which the toner is released from the surface of the cloud roller 13d, or the toner irregularly moves on the surface of the cloud roller 13d, and in the vicinity of the contact portion between the cloud roller 13d and the toner layer thickness regulating member 13e. The toner does not stay. As a result, it is possible to prevent toner sticking at the contact portion between the cloud roller 13d and the toner layer thickness regulating member 13e, and to prevent disturbance of the toner thin layer on the cloud roller 13d.

2) Since the driving (rotation) of the cloud roller 13d is stopped during the actual development, there is no air flow toward the contact portion generated by the rotation of the cloud roller 13d. As a result, it is possible to increase the probability that the toner staying in the vicinity of the contact portion is released from the vicinity of the contact portion and moves.

3) Since the cloud roller 13d is rotationally driven in the opposite direction to that during development during the actual development, the toner staying in the vicinity of the contact portion is conveyed upstream in the rotation direction on the cloud roller 13d, and in the vicinity of the contact portion. The probability that the toner staying in the area will be removed from the vicinity of the contact portion increases.

4) During the actual development, the potential difference of the voltage that makes the number of reversals twice or more is larger than the potential difference at the time of development, so the initial speed at which the toner hops from the cloud roller 13d increases. As a result, the speed at which they are released and moved by applying a high-frequency voltage is increased, and the probability that the toner staying in the vicinity of the contact portion is removed from the vicinity of the contact portion is increased.

5) During actual development, a voltage of +50 V or more is applied to the toner layer thickness regulating member 13e with respect to the central potential of the potential difference with different number of inversions. A force is applied in a direction away from the regulating member 13e, and as a result, the probability that the toner staying in the vicinity of the contact portion is removed is increased.

6) In 2) to 5), since the probability that the toner staying in the vicinity of the contact portion is removed increases, the same effect as in 1) is obtained.

  In this embodiment, the image carrier in the claims is the photosensitive drum 11, the developer is the toner, the developer carrier is the cloud roller 13d, and the first electrode is the odd-numbered electrode 21 or the even number. The second electrode corresponds to the even-numbered electrode 22 or odd-numbered electrode 21, the voltage applying means corresponds to the drive circuit, and the regulating member corresponds to the toner layer thickness regulating member 13e.

  Furthermore, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention, and all the technical matters included in the technical idea described in the claims are all included. The subject of the present invention. The above-described embodiments show preferred examples, but those skilled in the art can realize various alternatives, modifications, variations, and improvements from the contents disclosed in the present specification. These are included in the technical scope described in the appended claims.

11 Photosensitive drum 13d Cloud roller 13e Toner layer thickness regulating member 21 Odd side electrode 22 Even side electrode

JP-A-3-21967 JP 2002-207355 A

Claims (8)

A developer carrier for conveying the developer to the image carrier;
A first electrode provided on the developer carrier and a second electrode provided via an insulator with respect to the first electrode;
Voltage application means for applying an alternating voltage in which the potential difference between the first electrode and the second electrode is temporally reversed, and clouding the developer;
A regulating member that forms a preset gap with the developer carrier and regulates the layer thickness of the developer remaining on the developer carrier after development,
With
A developing device in which the number of inversions per predetermined time of the alternating voltage applied between actual developments is twice or more that during development. The developing device according to claim 1,
A developing device in which the driving of the developer carrying member is stopped between the realized images. The developing device according to claim 1,
A developing device in which the developing carrier is rotationally driven in a direction opposite to that during development between the realized images. The developing device according to any one of claims 1 to 3,
A developing device in which the potential difference of the voltage in which the number of inversions is twice or more between the realization images is larger than that during development. The developing device according to any one of claims 1 to 4, wherein
A developing device in which a voltage of +50 V or more is applied to the regulating member between the realization images with respect to the central potential of the potential difference with different number of inversions.   An image forming apparatus comprising the developing device according to claim 1. The image forming apparatus according to claim 6,
An image forming apparatus in which a plurality of developing devices are provided for each color and image formation is performed by superimposing images developed for each color. With respect to the first electrode provided on the developer carrying member and the second electrode provided on the first electrode via an insulator, the potential difference between the two electrodes is temporally changed by the voltage applying means. A cloud process for applying an alternating voltage that reverses to cloud the developer,
The surface of the developer carrying member is moved relative to the image carrier, the developer on the surface of the developer carrying member is conveyed to a developing region, and the latent image is developed;
With
A developing method in which, in the developing step, the number of inversions per unit time of the alternating voltage applied between the realized images by the voltage applying unit is twice or more that during development.