JPS58121052A - Developing method and its device - Google Patents

Abstract

PURPOSE:To obtain a picture having good quality, which has no fog, is stable over a long period of time, and also is scarcely varied by environment, by varying an electric field applied between a carrying body of a latent image and a feed means of a developer, in accordance with charge, etc., of the developer. CONSTITUTION:In a pre-rotation process, a photoconductive drum 1 is formed in a state that there is no latent image, a sleeve 22 is rotated, a uniform thin toner layer is provided on the sleeve 22 by a control blade 4, it is detected by a surface potential sensor 5, this detecting signal is inputted to a developing bias control unit 6, deflection from the surface potential of a prescribed toner layer is decided, and a correcting signal of an electric field applied between the drum 1 and a developing roller 2 is sent to a developing bias electric power source 7 or/and 9. For instance, in case when a charge generating state by triboelectric charging has dropped remarkably at the time of high environmental humidity, it is detected by the potential sensor 5, and an output for correcting the bias applied voltage of DC or AC is generated from the unit 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming apparatus such as an electrophotographic image forming apparatus, and relates to a method and apparatus for visualizing an image using a developer.

In conventional development methods, the toner and carrier are biological substances.
[Magnetic brush viewing method using #L cupping, cascade'
These methods, which have been widely put into practical use, are excellent methods that can obtain relatively good images, but on the other hand, they cause deterioration of the carrier,
It addresses a common drawback of two-component fluids, namely, variations in the mixing ratio of carrier and toner.

In order to avoid such drawbacks, a developing method using a one-component method consisting only of toner has been proposed, but the current 1J#! The method using a drug is better.

US 1FF-No. 3,909,258 also proposes a method of producing this effect using conductive rutted toner. This is a cylindrical quadrilateral sleeve with a magnet inside that holds a quadrielectric peak toner, which is brought into contact with an electrostatic latent image and developed by inducing an electric charge to the toner. ◎This current printing method is an excellent method that avoids the problems of the conventional two-component imaging method, but on the other hand, since the toner has four charges, it is possible to remove one layer from the recording medium in consideration of #. A disadvantage is that it is difficult to electrostatically transfer the electrostatic charge to a solid support.

A force mechanism using an insulating magnetic toner with a steerable transfer force, a toner that utilizes electric dispersion of toner particles, friction between toner particles, and a sleeve between toner particles, etc.) A method is known in which particles are allowed to settle and an electrostatic latent image is developed by contact. However, in these methods, since the toner comes into contact with both image and non-image areas, it is difficult to avoid toner adhesion to non-mis areas, so-called ground force blur, and also toner particles and umbrellas. The number of times of contact with the cleaning member is small, which tends to result in insufficient JLL-JI'1, and the Coulomb force of the charged toner particles with the sleeve becomes strong, causing them to stick vertically on the sleeve, which may be a disadvantage. Ta.

In contrast, the toner layer on the toner carrier is not brought into direct contact with the surface of the toner carrier, and the toner on the toner carrier is fluoresced by the electric field of the electrostatic M image. The jumping method, which allows the image to fly selectively to the image plane, has no 11ilI source capri, and has a clear a] visual 1 the 1
Can you get G? This is an old method. This toner image is easily electrostatically transferred to a recording material such as paper.

The upper female self-jumping development method removes the magnetic toner.
At the same time, the toner carrier is coated thinly with a toner regulating member, and the toner carrier is electrostatically deposited directly on the body, and at the same time, the toner is jumped by an electrostatic electric field. The cycle is repeated in which the toner is electrostatically charged and turned into an image, and then the remaining toner on the toner carrier is further transferred to the toner regulating member, where it is used for toner coating.

Although the toner is uniformly coated with the S material, the amount of charge is not particularly controlled.

However, the present invention has discovered that toner IIIEO1 changes due to visual humidity or deterioration due to long-term use, and thus the image density changes even if the toner coat layer thickness does not change. The analogy of environmental humidity is, of course, significant for insulating toner, especially for humid FI.
Under the L#a condition, charging due to the #I characteristic is insufficient, and therefore the toner charge decreases, resulting in a decrease in the current dispersion ability. In addition, in an extremely low humidity environment, on the contrary, the charge generation by A11 Son Teiden is strong, and the Coulomb force between the particles and the sleeve becomes strong, which tends to form a fixed layer on the sleeve, and the M effect, which should contribute to development, becomes strong. This causes the inconvenience that the number of toner layers decreases.

In addition, due to long-term use of the developing device, toner components adhere to the surface of the toner carrier, causing changes in the thickness of the toner.

Furthermore, in the jumping development 1c of toner poured into loquat (
-The charge distribution of the toner and the quality and weight of the toner particles change in the process of toner consumption, because the jumping current occurs depending on the amount of charge on each toner particle or the size of the particle. If you do so, the developability will change accordingly.
Corps, the princess's feet of concentration will be brought to you.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a developing method and method which solves the above-mentioned problems associated with the developing method using an insulating magnetic toner. The purpose of the present invention is to provide a developing method and apparatus that are stable over a long period of time without any turbulence, and which are less susceptible to fluctuations due to viewing and provide rich, high-quality images.

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2, which show embodiments of the present invention.

The explanation will be centered on FIG. Reference numeral 1 denotes a photosensitive drum that vibrates a photoconductive layer, and a desired half agI is formed by an electrostatic membrane-forming biofilm (not shown). A developing roller 2 rotates on the outside of the magnet roll 21 so as to maintain a predetermined gap between the magnet roll 21 and the photosensitive drum. A container 011 consisting of the bottom of the sleeve 22 is a container for storing the bottom of the insulating magnetic toner particles, and is provided so as to store a part of the aspect of the sleeve 22. Incidentally, 10 is a scree for replenishing toner particles To.

Reference numeral 4 denotes a blade that regulates the number of the single layer of toner formed on the sleeve 22, and is placed above the sleeve 22 so as to be at a predetermined distance M from the sleeve 22 and to face the position of one magnetic pole N of the magnet roll 2.1. are placed close together.

Reference numeral 5 denotes a non-contact type potential sensor, which is one of the means for detecting the surface potential of the toner particles T on the sleeve 22, and is provided close to the sleeve 22 in front of the lump image and at the threshold between the blade 4 and the drum 1. .

6 is a signal to be adjusted to the applied voltage by the image bias control unit 7 and to be corrected in accordance with the signal from the potential sensor 5. ．． 9. ◇The DC and AC bias applying power supplies 7 and 9 are both used to apply a bias between the visual image roller 2 and the drum 1, and move the toner due to the electrostatic charge on the drum 1. The AC bias applying power source 9 is superimposed on the DC bias applying power source.

Reference numeral 23 denotes a scraper for scraping toner off the surface of the sleeve 22, and is provided on the sleeve entrance side in the container 11 so as to cover the entire sleeve 220 and both sides.

Here, the violet of the charged toner layer whose thickness is regulated by the blade 4 can be detected by the potential sensor 5 as the corresponding surface potential.

In this embodiment, the toner layer on the sleeve 22 depends on its surface potential. Although the developing bias electric field control step may be performed simultaneously with the above-described developing step, it is actually more appropriate to perform it as a pre-step prior to the developing step. That is, first, as a pre-rotating punch, a blank sheet is placed on the photoconductor drum 1.
At the same time, the sleeve 22
By passing through the position of the regulating blade 4 while rotating 1g of toner, a uniform thin layer of toner is coated on the sleeve 22.

This uniform thin layer of toner I- is detected by the surface potential sensor 5, and a detection signal is sent to the developing bias control unit 6.
sent to. The specified toner layer surface potential is now cut off and the signals necessary to modify the electric field applied between the photoconductor drum 1 and the developer roller 2 are developed from the developer bias control unit 6. It is sent to the bias power supply 7 and/or 9.

1. For example, if the environmental humidity becomes abnormally high and the charge generation caused by electrification drops noticeably, the charge generation on the toner layer on the sleeve will be affected to some extent, and the charge will become smaller and the sleeve will The surface potential of the upper toner layer decreases. In this case, in jumping development using the normal JllIt bias setting, sufficient development is not achieved because the toner agglomeration ability is further reduced, and the density of the final image is therefore low. Since the value detected by the potential sensor 5 during the pre-rotation process is naturally low, the developing bias control unit 6 outputs an output for modifying the applied DC bias voltage or the voltage of the AC bias. As a result, the development efficiency of jumping development, etc. is corrected to a normal level, and the quality of the developed image is stabilized.

Control involving such a pre-rotation process need not be performed for each copying cycle, but may be performed at intervals that follow changes in environmental humidity, toner consumption, and the degree of deterioration. Therefore, the purpose can be achieved by adding nine operations corresponding to the length of the copying pause time. 2 is an explanatory diagram of another embodiment of the present invention, which has the same members and configuration as those in FIG. 1, and the different configurations are clear from the figure.

Reference numeral 3 denotes an application roller for supplying toner to the developing roller 2, which has the same structure as the developing roller 2 and is disposed close to the developing roller 2. Reference numeral 8 denotes a bias applying power source for transferring toner when supplying the toner from the application port roller 3 to the developing roller 2.

*The magnet roll 31 of the cloth roller has an S pole in a portion close to the magnet roll 21 and does not have an N or S pole on the magnet roll 21 side. Further, the magnet roll 21 has an S pole at a portion close to the first section drum 1@. Furthermore, N above the magnet roll 31
A regulating blade 4 is provided at a position facing the pole.

Toner is supplied from a toner container and held on the application roller 3 by magnetic force. The toner conveyed by the rotation of the sleeve 320 is uniformly coated with the layer thickness regulated by the blade 4. The toner is electrically charged as it is conveyed on the sleeve and at the friction temples when regulating the layer thickness at the blade section. The toner charged and uniformly applied on the sleeve 32 moves to the roller 2 at a position where the application roller 3 faces the developing roller 2, and is applied onto the sleeve 22.

The toner is transferred from the coating roller 3 to the developing roller 2 by an electric field generated by a power source 8 applied between the developing roller 2 and the coating roller 3.゛The toner moved by the magnetic field and transferred to the sleeve 22 is held by the magnetic force of the magnet roll 21 and the electrostatic force between the sleeve 22, moves on the developing roller by the rotation of the sleeve 22, and is placed opposite the drum 1. to visualize the electrostatic charge on the drum. The residual toner on the sleeve 22 after development is removed by a scraper 23.
It is destroyed by.

In this example, as well as the example shown in FIG. 1, the electrostatic residue image control during the development process is carried out based on the detected potential of the surface potential sensor to control the charge on the toner layer on the sleeve 22. Do it before.

A feature of this example is that the magnet roll structure of the developing device is separated into an application roller and a developing roller. Even if the thickness of the toner becomes uneven due to foreign matter or aluminized toner in the pick blade section 4, the toner is transferred from the coating roller 3 to the developing roller 2 and is almost completely removed during the coating process. The developing roller is able to form a uniform layer of toner without any unevenness.In addition, since the coating method from 3) is an electric field process, it is possible to form small toner particles or large angular toner particles. The toner particles cannot be transferred to the developing roller 2, and the amount of charge of the toner particles is almost uniform and only particles of a certain size are transferred to the developing roller 2, such as a fist.

FIG. 3 shows the potential sensor 6 in the above-mentioned embodiment of the main emission.
An explanatory diagram for explaining an example of the position of the tongue, - has a white area A on the entire cheek area 0 This white area A is located on the optical means P
This is the part that always forms a white image even when exposed to light. Photosensitive drum 1 corresponding to this white area A
The upper end is formed in the area B by means of the optical means P. Therefore, the area B corresponding to the entrapment area B of the developing roller 22 (FIG. 1, FIG. 2) and the applicator roller 32 (FIG. 2), respectively. In the area ', the toner particles T do not move to the photosensitive drum 1 even immediately after the electrostatic latent image is developed.

Therefore, the potential sensor 6 is located close to this region B'.
1 tl-, the potential on the sleeve 22 can be measured at all times, so the charge on the toner layer or the surface potential corresponding to this can be measured at any time or at all times, and The reference '1 position (or charge) is stabilized under excellent control. be able to.

In the figure, an example in which the surface of the photosensitive drum 1 is directly exposed with the lamp 13 without providing the white area A, and the exposed area B1 is determined by the reflective shade 12 is also shown by the two-dot broken line. The roller 22 (or developing roller 22) corresponding to this area B1
A toner charge amount detecting means is provided in the region B/ of the application roller 32) and the application roller 32).

In this way, the charging of the toner can be controlled at all times or when necessary, as described above.

In addition, the potential sensor 6 shown by a dotted line shows an example when the entire surface of the photosensitive drum is exposed or as shown in FIGS. 1 and 2. In each of the above embodiments, the magnetic roller is fixed and the sleeve is rotated. However, it is also possible to rotate both of them in the opposite direction, or to supply developer such as toner particles to the round developing reservoir. good.

As described above, the present invention is a developing method and apparatus capable of performing stable development unaffected by the environment.

FIG. 4 is a flowchart of an embodiment based on the present invention. In the figure, α corresponds to the electric charge of the agglomerate (toner) detected by the potential sensor, and represents a signal of nine curved potentials. There is. In addition, Ar e At Bs eBt and C are reference signals corresponding to the surface potential, and their magnitude relationship is At >
The surface potential is vaguely high as A > Bs > Bt > C, and the surface potential in the range suitable for development is B,
≧α≧B1, and the dovetail signal is taken as signal B. 0 Furthermore, E indicates the amount of positive applied bias that increases the predetermined bias, D>E, and H, F, and G indicate that the predetermined bias is increased. It shows the amount of decreasing bias to be decreased (so as to apply a small or zero bias to thlc), and H<F<G. 0 Now, when the main switch of the entire device is turned on, the system waits at check #rS1 until the copy key (start signal) is turned on. 0 When the copy key is turned on, the pre-rotation is performed and the process starts. is started and the process P1
A normal predetermined bias is applied at , and the normal surface potential (
If the signal B, ≧α≧Bl), a state is established in which excellent development can be performed. Next, drum 1 and sleeve 2
2. It is determined in judgment S1 that the sleeve 22. (32) rotates, and the postmortem punch P2 rotates the sleeve 22. (32) The above surface potential is detected by the potential sensor, and judgments S3 to S7 are performed on the sensor signal α as shown in the following table. That is, it is determined which reference signal the surface potential is located between, and the sexual roots P3 to P8 shown in the figure are determined, respectively.

In this way, the application/(ias) is increased or decreased in accordance with the range to correct the desired charging state of the developer (toner).

The following nine judgment steps are performed. Furthermore, after the copying is completed and the person dies, all the previous temperature-sensing processes can be reset, or the 9 judgment processes before the end can be memorized in a known storage means, and the next process can be performed from this memory state. Good 6) Prepare for the first step. This determination and temperature sensing content may be performed by known electrical means or the like so as to act on the IAScon current power source 7 and/or the bias application AC power source 9.

Further, by dividing the six cells, control may be performed only when the potential drops below a predetermined level, or when the voltage rises after a drop, so that the voltage is converted into several blocks.

It is more preferable that the developing powder that can be applied to the developing device of the present invention is insulating and magnetic;
It is more preferable to use one containing a layer of mm and magnetic powder in terms of the ability to use t=f. Magnetic powders include ferromagnetic elements and alloys and compounds containing them, sb,! Dannetite,
There are substances conventionally known as HA materials, such as alloys and compounds of iron such as hematite and ferrite, cobalt, nickel, and manganese, and other strong cicada alloys. The average particle size of the magnetic powder that is usually used is 0.05.
-5μ, preferably 0.1-1μ, and this magnetic powder has a weight of 10-70μ, preferably 15-50μ, in the developing powder.
It is better if it contains a lot of weight. All known binder resins can be used, such as polystyrene,
Monopolymers of styrene and its substituted products such as poly-P-chlorostyrene and polyvinyltoluene, styrene-P-chlorostyrene copolymers, styrene-globylene copolymers,
Styrene-bitoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic methyl copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer , styrene-methacrylic methyl co-1
combination, styrene-methacrylic plate ethyl copolymer, styrene-butyl methacrylate coelectrolyte, styrene-α chloromethyl methacrylate coelectrolyte, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinylethyl ether conjugate,
Styrene/-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-imprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer, etc. styrenic coelectrolyte, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene,
Polyester, polyurethane, polyamide, epoxy resin, poly(x-nylbutyral), polyamide, polyacrylic resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorine Chemical paraffin, paraffin wax, etc. can be used alone or in combination.

In addition, carbon black, various apple dye pigments,
Examples include hydrophobic colloidal silica fine powder and plasticizers.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams for explaining one embodiment of the developing device or its method according to the present invention, FIG. 3 is an explanatory diagram for explaining an example of the positional relationship of potential sensors, and FIG.
The figure is a flow chart diagram of one embodiment of the present invention. 1 is a photosensitive drum, 2 is a developing roller, 3 is a coating roller, 4 is a blade, 5 is a potential sensor, 6 is a #4m bias control unit, 7 is a (developing) DC bias application power supply, 8 is a (coating) application power supply, 21, 31 are magnet rolls, 22.32 are sleeves, 23.33 are scrapers 〇 Applicant Canon Co., Ltd. Figure 8P

Claims (1)

[Scope of Claims] (υ In a developing method in which the developer is supplied to a carrier carrying a 1w image to form a single image, A regulating method characterized in that the visualization of all is controlled by varying the electric field applied between the carrier and the supply means according to the method (2J); The IW image is produced by supplying a carrier that carries the IW image and a developer that charges M.
4.4a, a means for detecting the charge or potential of the developer, a means for applying an electric field between the carrier and the developing surface, and an applying means according to the m number of the detecting means. A developing device 0 characterized in that it has an applied electric field t- +K for controlling