JP2001121735A - Method and apparatus for forming image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a high printing speed without causing tailing in the case where an image for controlling a toner fly track is formed with the use of deflecting electrodes 10a and 10b. SOLUTION: A process of controlling passage by one dot by a toner pass control means 4 is comprised of a promote process of promoting toner's passing a toner pass hole 6 in accordance with an image signal from the outside, and a suppress process of suppressing toner's passing the toner pass hole 6 immediately after the promote process. In accordance with an increase of a distance between two dots formed on an image-receiving member 5 from the same toner pass hole 6 through a deflect process, a period of the suppress process in the passage control process which contributes to the image formed earlier of the two dots is made longer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a copying machine, a facsimile, a printer, and the like. In particular, a developer passage control means controlled by an image signal controls the flying of a developer from a developer carrier to a back electrode. The present invention belongs to a technical field related to an image forming apparatus and an image forming method for performing image formation by controlling and attaching a developer to an image receiving member located between a developer passage control unit and a back electrode.

[0002]

2. Description of the Related Art In recent years, with the improvement of the capabilities of personal computers and the advancement of network technology, there has been a social demand for printers and copiers capable of handling a large amount of documents and having high processing capabilities capable of handling color documents. Is getting stronger. However, an image forming apparatus that is capable of outputting a satisfactory high-quality monochrome or color document, which is a high-speed image forming apparatus, is under development and is expected to appear.

[0003] Conventionally, for example, Japanese Patent Publication No. 44-2633.
No. 3, U.S. Pat. No. 3,689,935 (see Japanese Patent Publication No. 60-20747) and Japanese Patent Publication No. 9-500.
An image forming technique of a direct printing method disclosed in Japanese Patent Application Publication No. 842 and the like, in which a developer such as toner is caused to fly on an image receiving member such as a recording paper or an intermediate image carrying belt by the action of an electric field to form an image. ing.

[0006] The principle of the direct printing method will be described with reference to FIGS. 6 and 7. FIG. 6 is a schematic diagram showing an image forming apparatus according to the above method. For example, a toner passage control unit 4 for controlling toner flying is disposed between the toner carrier 2 that carries the negatively charged toner 1 and moves and the back electrode 3. The image receiving member 5 is transported. The toner passage control means 4 uses an insulating member as a base material, and has a plurality of toner passage holes 6 through which toner passes and a control electrode 7 around each toner passage hole 6.

The toner carrier 2 is grounded, and the back electrode 3 is connected to a back electrode power supply 8. The control electrode 7 is connected to a control electrode power supply 9. The control electrode power supply 9 repeatedly outputs a pulse-like control voltage according to an external image signal.

If the polarity of the control voltage supplied from the control electrode power supply 9 to the control electrode 7 is the same as the toner charging polarity,
Since the toner 1 on the toner carrier 2 has an electrostatic adhesion in the direction of the toner carrier 2, the toner 1 is
Do not fly from. When the polarity of the control voltage supplied from the control electrode power supply 9 to the control electrode 7 is opposite to the toner charging polarity, the toner 1 acts on the toner carrier 2 by the action of electrostatic adhesion toward the control electrode 7. Detached from further,
By supplying a voltage having a polarity opposite to the toner charging polarity from the power supply 8 for the back electrode to the back electrode 3, an electrostatic adhesion toward the back electrode acts on the toner 1. Thereby, the toner 1
Is passed through the toner passage hole 6 and the toner passage control means 2
Adheres to the image receiving member 5 conveyed between the first electrode and the back electrode 3.

Further, Japanese Patent Publication No. 59-38908 and the Journal of the Society of Electrophotography, Vol. 36, No. 2 (1997), p. 114-1
17, a plurality of dots can be formed from one passage hole by deflecting and converging the flying toner.

FIG. 7 is a principle diagram showing the state of deflection.
FIG. 7A is a diagram showing the direction of toner deflection, and FIG.
7B is a time chart of the voltage (V7) applied to the control electrode 7, FIG. 7C is a time chart of the voltage (V10b) applied to the right deflection electrode 10b, and FIG.
4 shows a time chart of a voltage (V10a) applied to the left deflection electrode 10a.

On the back electrode 3 side of the toner passage control means 4,
The two divided deflection electrodes 10a and 10b are inserted into the toner passage holes 6
Are placed symmetrically with respect to the center of. Further, deflection power supplies 11a, 11b are supplied to the two divided deflection electrodes 10a, 10b.
Apply different voltages from b. As a result, the symmetry of the electric field around the toner passage hole 6 is broken, and the trajectory of the toner passing through the toner passage hole 6 is deflected from the center of the toner passage hole 6. As a result, the toner lands on the image receiving member 5 at a position away from the central axis of the toner passage hole 6, and a dot is formed. Further, by applying the same voltage to the deflection electrodes 10a and 10b, the toner lands on the central axis of the passage hole and a dot is formed.

As described above, by controlling the deflection voltage applied to the deflection electrodes 10a and 10b, dots can be formed at a plurality of positions on the image receiving member from one passage hole. Even when the number of the toner passage holes 6 provided in the image forming member 4 is small, a high-resolution toner image can be formed on the image receiving member.

The left side of FIG. 7 shows that the voltage (V _H ) applied to the deflecting electrode 10a disposed on the left side of the toner passage hole 6 is disposed on the right side when viewed in a direction orthogonal to the conveying direction of the image receiving member 5. (V _L ) applied to the deflection electrode 10b
FIG. Accordingly, the flight trajectory of the negatively charged toner 5 is changed by the two deflection electrodes 10a and 10a.
It is deflected to the left by the electrostatic field generated between b. The left-right center in the figure shows a case where the deflection electrodes 10a, 10b both to the same voltage (V _M) is applied. As a result, the charged toner advances straight toward the image receiving member 5 as indicated by the arrow, and reaches a position on the image receiving member 5 opposite to the position of the passage hole. Further, on the right side of the figure, the voltage (V _H ) applied to the right deflection electrode 10b is
This shows a case where the voltage is relatively higher than the voltage (V _L ) applied to a. As a result, an electrostatic field is formed between the deflection electrodes 10a and 10b in a direction opposite to that of the left part of the figure, and the trajectory of the negatively charged toner 5 is deflected to the right. The deflection process of the flight trajectory of the toner as described above, that is, deflection to the left,
The straight traveling and the rightward deflection are continuously repeated while the image receiving member 5 is conveyed, so that a toner image is formed on the image receiving member 5. In the following description, each of the above deflection steps is abbreviated as a left deflection step, a straight traveling step, and a right deflection step. Further, a cycle in which the deflection steps up to are repeated is abbreviated as a full deflection step cycle.

[0012]

However, in the image forming apparatus having the above-described structure, a so-called tailing phenomenon occurs in which a portion of the toner lands on the image receiving member 5 at a position different from the regular dot forming position. There is a problem that occurs. FIG. 8 shows a state diagram of a line image in which the tailing phenomenon has occurred. The tailing phenomenon referred to here means that, as shown in the right deflection line portion in FIG. 8, the toner trails as shown in B in FIG. The phenomenon of sticking.

The principle of occurrence of the tailing phenomenon will be described below with reference to FIGS. FIG. 9 is a diagram illustrating the principle of occurrence of the tailing phenomenon for explaining the principle of occurrence of the tailing phenomenon.
(A) to (c) show how the flying state of the toner changes continuously. That is, FIG. 9A shows the toner flying state during the right deflection process, and FIG.
9 shows the flying state of the toner immediately after switching from the right deflection step to the left deflection step, and FIG. 9C shows the toner landing state on the image receiving member 5 during the left deflection step.

In FIG. 9, reference numeral 13 denotes a toner column discharged from the toner passage hole of the toner passage control means. Toner carrier 2
The toner layer carried thereon contains toner particles having different charge amounts and particle sizes. When the charge amount and the particle size are different, the electrostatic force and the air resistance acting on each toner particle while being separated from the toner carrier 2 and flying toward the image receiving member 5 are different. For this reason, the flying speed of the toner fluctuates while flying, and as a result, the toner flies in a columnar shape. Further, some toner particles of the flying toner contact the inner wall of the toner passage hole 6. As a result, frictional resistance with the inner wall of the toner passage hole 6 acts, and the flying speed of the contacting toner particles is reduced. As a result, the variation in the flying speed between the toner that contacts the inner wall of the toner passage hole 6 and the toner that does not contact the toner wall increases, and the length of the toner column 13 that has passed through the toner passage hole 6 increases.

Arrows T ₁ , T in FIGS.
Reference numeral ₃ denotes the flight trajectory of the toner due to each electric field. Arrow T ₁ ,
As shown in T _3, the deflection electrodes 10a, in the vicinity of 10b,
The trajectory of the toner is greatly deflected because it is strongly affected by the electric field formed by the deflection electrodes 10a and 10b. When approaching the back electrode 3, the electrostatic attraction to the back electrode strongly acts on the toner particles, so that the flying trajectory of the toner is in a direction substantially perpendicular to the image receiving surface of the image receiving member 5. The other symbols shown in FIG. 9 are the same as those in FIG.

Next, the process until the tailing phenomenon occurs will be described with reference to FIG.

First, during the right deflection step shown in FIG. 9A, the toner column 13 is deflected to the right in the figure and flies.
Next, as shown in FIG. 9 (b), it proceeds from right deflection step to the left deflection step, the electric field trajectory of the toner as indicated by an arrow T ₁ is deflected to the left are formed. However, immediately after the shift to the left deflection step, the rear end of the toner column 13 has not reached the image receiving member 5. For this reason, electrostatic attraction in the direction of arrow F in FIG. 9B acts on the toner particles at the rear end of the toner column 13. As a result, as shown in FIG. 9C, the toner particles at the rear end of the toner column land on the left side of the normal landing position, causing a tailing phenomenon as shown in FIG.

The tailing phenomenon as described above occurs when the distance between the dots landed on the image receiving member continuously is long, that is,
This is noticeable when the difference between the deflection voltages applied before and after switching the toner trajectory is large. For example, in FIG. 7, the difference between the deflection voltage levels of the right deflection process and the left deflection process is the largest compared to the difference between the other deflection processes. Therefore, when shifting from the right deflection process to the left deflection process, a tailing phenomenon is likely to occur. This is because the relative amount of change in the electric field strength relative to the deflection direction of the toner flight trajectory is greater than the others, so that the toner lands on the image receiving member following the change in the electric field strength.

The above-described tailing phenomenon occurs remarkably as the printing speed increases. This is because when the printing speed increases, the time required for supplying a control voltage to the control electrode in order to discharge the toner for one dot from the toner passage control means, that is, the passage control process for one dot is shortened. At the same time, the deflection process time for switching the toner trajectory in synchronization with the passage control process time is also reduced. As a result, the toner cannot land on the image receiving member before the deflection process is switched. For this reason,
In order to suppress the occurrence of the tailing phenomenon, it was necessary to reduce the printing speed.

As means for solving the above-described tailing phenomenon, means for shortening the toner column can be considered. Specifically, it is a method of making the charge amount and the particle size of the toner particles uniform. However, in order to make the characteristics of the toner uniform,
There is a problem that the yield in toner production is reduced.

In view of the above problems, the present invention provides an image forming method and an image forming method for controlling a toner trajectory using a deflection electrode without causing a tailing phenomenon and without reducing a printing speed. It is intended to provide a device.

[0022]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, there is provided a carrying step of carrying a developer carried on a developer carrying member, and a developing step carried in the carrying step. The passage control step of sequentially controlling the passage of the developer conveyed to the positions facing the plurality of developer passage holes of the developer passage control means of the developer passage control means; A deflection step of sequentially deflecting the flight trajectory of the developer sequentially passing through the developer passage hole in synchronization with the passage control step; and sequentially landing on the image receiving member the developers sequentially deflected to different flight trajectories by the deflection step. An image forming method comprising:
The passage control process for one dot includes an accelerating step of accelerating the passage of the developer through the developer passage hole in response to an image signal from the outside, and suppressing the passage of the developer through the developer passage hole immediately after the accelerating step. And a suppression step.

As the distance between two dots formed by successive landing steps increases, the period of the suppression step in the passage control step, which contributes to the dot formed earlier of the two dots, increases. Lengthen.

In other words, according to the present invention, under the condition where the tailing phenomenon is likely to occur, that is, under the condition where the distance between two dots continuously formed on the image receiving member becomes long, the passage control of the previously formed dot is performed. The suppression process period in the process becomes longer. For this reason, before the passage control process of the next dot to be formed is started, all the developer flying before landing on the image receiving member or the flying trajectory of the developer affects the deflection electric field. You will reach a position that you do not receive. Therefore, when the deflection process is switched, the developer before landing, which causes the tailing phenomenon, does not remain between the developer passage hole and the image receiving member.

According to the present invention, the period of the promotion step is made variable in accordance with an external image signal.

Thus, the amount of the developer passing through the developer passage control means can be adjusted, so that the dot density formed on the image receiving member can be reproduced in multiple gradations.

According to a third aspect of the present invention, the length of each of the passage control process periods is an integral multiple of the shortest passage control process period.

As a result, the timing for starting the promotion step in each passage control step is always kept constant.

According to the fourth aspect of the present invention, dots formed by the developer sequentially landed on the image receiving member through the same developer passage hole via the deflecting step are formed by D ₁ , D ₂ ,..., D _n (n is And an integer of 3 or more), and let T ₁ , T ₂ ,..., T _n be the periods of the passage control step that contributes to the formation of dots from D ₁ to D _n , and D ₁ , D _{2 ,.} It is assumed that dots are repeatedly formed on the image receiving member in order, and that the expression T ₁ = T ₂ =... = T _n-1 <T _n is satisfied.

By satisfying the above equation, among the pass control steps performed in the entire deflection step cycle, the pass control step longer than the period of the other pass control steps is performed only at the end of the entire deflection step cycle. Will be implemented. This allows T ₁ to T _n
Is shortened, and as a result, the printing speed is increased. Further, by satisfying the above expression, all the time differences ΔT from the start of the predetermined passage control step to the start of the next passage control step become equal within the entire deflection step cycle. Therefore, assuming that the image receiving member is moving at a constant velocity v, the period from when the dot D _k (k is an integer of 3 to n−1) lands on the image receiving member until D _{k + 1} lands. In addition, the distance L _k by which D _k is conveyed by the image receiving member is ΔT ×
It is always constant at v (v is the conveying speed of the image receiving member). Therefore conveying direction improvement of the image receiving member, by landing on the image receiving member by deflecting the D _k only forward advance distance L _k from landing scheduled position of D k _{+ 1,} and D _k and D _{k + 1,} the image receiving member Are formed at the same position in the direction perpendicular to the transport direction.

Further, according to the invention of claim 5, a developer carrying member for carrying and transporting the developer, an image receiving member provided opposite to the developer carrying member for receiving a developer image, and the developer carrying member A developer passage control means disposed between the image receiving member and a plurality of developer passage holes through which the developer carried by the developer carrying member passes toward the image receiving member; And a control voltage for controlling the passage of the developer through the developer passage hole in accordance with an external image signal in order to form one dot on the image receiving member. Control voltage supply means for supplying the control electrode with the control electrode, a deflecting electrode disposed around each of the developer passage holes to deflect a flight trajectory of the developer from the developer passage control means to the image receiving member, and a control voltage. Supply to deflection voltage in synchronization with An image forming apparatus having a sequential switching deflection voltage supply unit a voltage level, said control voltage supply means is supplied to the deflecting electrodes for two consecutive
As the difference between the two deflection voltage levels increases,
The control voltage supply time is adjusted so that the control voltage supply time corresponding to the deflection voltage applied to the control electrode before one of the deflection voltage levels becomes longer.

According to this image forming apparatus, under the condition that the tailing phenomenon is likely to occur, that is, under the condition that the distance between two dots continuously formed on the image receiving member becomes long, it is possible to correspond to the dot formed first. The control voltage supply time becomes longer.
For this reason, before the control voltage supply time corresponding to the dot to be formed next, all the previously flying developer lands on the image receiving member, or the trajectory of the developer reaches a position where it is not affected by the deflection electric field. To reach. Therefore, when the level of the deflection voltage applied to the deflection electrode is switched, the developer before landing, which causes the tailing phenomenon, does not remain between the developer passage hole and the image receiving member.

According to the sixth aspect of the present invention, the control voltage of the control voltage supply means includes an accelerating voltage for promoting the passage of the developer through the developer passage hole and a suppression voltage for suppressing the passage of the developer through the developer passage hole. The application time of the accelerating voltage is adjusted in accordance with an external image signal.

With this configuration, the amount of the developer passing through the developer passage control means can be adjusted, so that the dot density formed on the image receiving member can be reproduced in multiple gradations.

In the present invention, each of the control voltage supply times is an integral multiple of the shortest control voltage supply time.

Therefore, the timing for starting the supply of the voltage pulse for promoting the passage of the developer through the developer passage hole within each control voltage supply time is always kept constant.

According to the eighth aspect of the present invention, dots formed by the developer flying from the same developer passage hole and passing near the deflection electrode and landing on the image receiving member are sequentially formed as D ₁ , D ₂ ,.
D _n (n is an integer of 3 or more), and control voltage supply times that contribute to the formation of dots from D ₁ to D _n are T ₁ , T ₂ ,.
When _{T n, D 1, D 2} , ..., such that dots on repeated image receiving member in the order of D _n are formed, sequentially switches the voltage level supplied to the deflection voltage at the deflection voltage supply means, The control voltage supply means adjusts the control voltage supply time so as to satisfy the equation T ₁ = T ₂ =... = T _n-1 <T _n .

By satisfying the above expression, the control voltage supply time longer than the other control voltage supply times out of the control voltage supply times corresponding to the plurality of dots formed in the entire deflection step cycle is changed. Set last in the cycle.
Thus, since the sum of the T ₁ to T _n becomes shorter, so that the printing speed is quickened. Further, by satisfying the above expression, all the time differences ΔT from the start of the predetermined control voltage supply time to the start of the next control voltage supply time become equal within the entire deflection process cycle. Therefore, assuming that the image receiving member is moving at a constant speed v, the dot D _k (k is 1 to n−
During a period from integer between 1) is landed on the image receiving member to the D _{k + 1} is landed, the conveying speed of the distance L _k is △ T × v (v is the image receiving member D _k is conveyed in the image receiving member ) Is always constant. Therefore, the conveyance direction improvement of the image receiving member, by landing on the image receiving member by deflecting the D _k forward by advance distance L _k from landing scheduled position of D k _{+ 1,} and D _k and D _{k + 1,} the image receiving The members are formed at the same position in the direction orthogonal to the conveying direction of the members.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an image forming apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a toner. In the present embodiment, a non-magnetic toner having a volume average 50% diameter of about 8.5 μm using a polyester resin as a binder resin is used.
In addition, as the binder resin used for the toner 1, a styrene-acrylic copolymer, a styrene-butadiene-based copolymer, an epoxy resin, and a mixed resin thereof are suitable. In addition, a magnetic toner containing a magnetic powder may be used.In this case, the magnetic powder includes ferrite, magnetite and other alloys and compounds containing ferromagnetic elements such as iron, cobalt, and nickel. It is valid. The holding power of the magnetic powder is suitably from 100 to 500 Oe, and the amount of the magnetic powder to the resin is suitably from 20 to 40% by weight based on 100 parts by weight of the toner particles. In addition, in order to control the fluidity of the charge control agent and the toner, silica (SiO ₂ ), titanium oxide (TiO ₂ ), a metal salt of stearic acid or the like is used in an amount of 0.1 to 5%.
It is preferable to add by weight. In particular, silica greatly affects fluidity, and can prevent toner from being clogged in a toner passage hole of a toner passage control unit described later. Further, since silica has a small diameter and a high chargeability, it is strongly attracted by electric force and easily adheres to the inner wall surface of the toner passage hole. However, the toner adhered to the inner wall surface of the toner passage hole serves as a roller for promoting the movement when passing through the toner passage hole, so that clogging of the hole can be prevented. Silica has a BET specific surface area of 100 to 300 m ² / g by nitrogen adsorption.
Those in the range are suitable. If silica having a small diameter of less than 100 m ² / g is used, sufficient fixing property cannot be obtained since the resin is mixed so as to be shredded.

Reference numeral 2 denotes a toner carrier 2 for carrying and transporting the toner 1. In this embodiment, the toner carrier 2 has an outer diameter of 20 mm and a thickness of 1 mm.
And the toner carrier 2 is grounded. The material of the toner carrier 2 may be made of a metal such as iron, an alloy, or a member obtained by winding a rubber material such as silicon rubber or urethane rubber around a core shaft in addition to aluminum. Further, in addition to the roller shape, a belt shape or a drum shape may be used. In addition to the grounding of the toner carrier 2, a DC voltage or an AC voltage may be applied. When an AC voltage is applied, a DC voltage may be superimposed.

A layer of the toner 1 is formed on the toner carrier 2 by a regulating blade (not shown). This regulating blade is formed of an elastic member such as urethane or silicon, and has a hardness of 40 to 80 degrees (JIS K6301A).
Scale).

The free end length (length of the portion protruding from the mounting member) of the regulating blade for regulating the toner layer with respect to the toner carrier 2 is 5 to 15 mm. The linear pressure on the toner carrier 2 by the regulating blade is suitably 5 to 40 g / cm, and the toner is formed on the toner carrier 2 by one to three layers by pressing the regulating blade. The regulating blade is used by electrically applying a float state, a ground state, or a DC or AC voltage. In the present embodiment, the regulating blade is used in a float state. The toner 1 is sandwiched between the toner carrier 2 and the regulating blade, and receives a small charge from the toner carrier 2 to receive and charge the toner.

The toner 1 is supplied to a supply roller (not shown).
At the surface of the toner carrier 2. The supply roller is
A synthetic rubber such as foamable urethane is formed to a thickness of about 2 to 6 mm on a metal shaft such as iron (diameter 8 mm in the present embodiment). The hardness of the surface of the supply roller is 30 degrees (measured by a method according to JIS K6301 A scale when processed into a roller shape). The amount of biting into the toner carrier 2 is preferably in the range of 0.1 to 2 mm. The supply roller is grounded,
Alternatively, a DC or AC voltage is applied. The supply roller controls the amount of toner supplied to the toner carrier 2 and assists in charging the toner 1. The charge polarity of the toner 1 may be either positive or negative. However, in the present embodiment, a negatively charged toner is used. Further, the charge amount of the toner is about −20 μC /
The type and amount of the charge control agent internally added to the toner were adjusted so as to obtain g.

In FIG. 1, reference numeral 3 denotes a back electrode, which is formed of a metal plate in this embodiment. In addition, a film in which a conductive filler is dispersed in a resin may be used. In this case, the resistance of the film is preferably about 10 ² to 10 ¹⁰ Ω · cm. The toner image is recorded by directly attaching toner on the back electrode 3 or by placing an image receiving member on the back electrode 3 and attaching toner on the image receiving member to form a toner image. Good. Further, the back electrode 3 may be processed into an endless film shape as described above, and the toner may be directly recorded on the film and then transferred to the image receiving member. The distance between the back electrode 3 and the toner passage control means 4 described later is preferably in the range of 50 to 1000 μm. In the present embodiment, the distance from the back electrode 3 to the toner passage control means 4 is set to 150 microns.

The back electrode 3 is connected to a back electrode voltage power supply 8 for supplying a constant voltage thereto. The voltage applied to the back electrode 3 is preferably from +500 V to +2000 V, and more preferably from +800 V to +1500 V. preferable. When the voltage applied to the back electrode 3 is higher than the above range, the toner passage control means 4 and the back electrode 3 are electrically short-circuited,
There is a risk that both will be destroyed by discharge. If the applied voltage is lower than the above range, the force of electrostatically attracting the toner 1 to the back electrode 3 side is weakened, and it is not possible to attract enough toner to the image receiving member 5 side to print high density dots. In the present embodiment, a voltage of +1000 V is supplied to the back electrode 3 by the back electrode voltage power supply 8.

4 is a flexible printed circuit board (hereinafter FP)
C) and is disposed between the toner carrier 2 and the image receiving member 5. The toner passage control means 4 has an insulating substrate 12, which is suitably 10 to 100 μm thick, and is preferably made of a material such as polyimide or polyethylene terephthalate. In this embodiment, a polyimide having a thickness of 50 μm is used. Reference numeral 14 denotes an insulating cover film provided on the insulating base material 12, and its thickness is suitably 5 to 30 microns. In the present embodiment, a polyimide film having a thickness of 10 μm is attached to both surfaces of the insulating base material 12 with an adhesive layer having a thickness of about 10 to 15 μm. Of course, the material, dimensions, number of constituent layers, and the like of the insulating base material 12 and the cover film 14 are not limited thereto, and may be arbitrarily designed.

The toner passage control means 4 is provided with a toner passage hole 6 passing therethrough. Processing for forming the toner passage hole 6 in the toner passage control means 4 is as follows.
It is possible to form a hole by excimer laser or press working. Alternatively, after performing a hole forming by YAG laser or CO ₂ laser or the like, post-processing such as etching may be performed. In the present embodiment, the one in which the toner passage hole 6 is formed by performing hole processing with an excimer laser is used. A plurality of the toner passage holes 6 are arranged along the longitudinal direction of the toner passage control unit 4, and the toner passage control unit 4 which forms a toner passage hole array and which is described in the present embodiment has two rows of toner passage holes. It has a row of holes. A control electrode 7 is disposed on the surface of the insulating base 12 on the side of the toner carrier 2 so as to surround the toner passage hole 6. In addition to the arrangement shown in the present embodiment, a control electrode 7 may be provided on the inner wall surface of the toner passage hole 6.

Deflection electrodes 10 a and 10 b are provided around the toner passage hole 6 on the surface of the insulating substrate 12 of the toner passage control means 4 on the back electrode 3 side. The control electrode 7 and the deflection electrodes 10a and 10b are made of copper foil or aluminum foil having a thickness of about 2 to 30 microns. In this embodiment, a 10-micron thick copper foil is used as the control electrode 7 and the deflection electrode 10.
a and 10b were used respectively.

The control electrode 7 is connected to a control electrode power supply 9, and the control electrode voltage power supply 9 supplies a voltage pulse to the control electrode 7 according to an image signal supplied from the outside. The control electrode voltage power supply 9 includes a voltage generator (not shown) for generating a voltage, and a switching element (not shown) for switching the voltage. One of the switching elements has about 32, 64, 128 channels, and controls the voltage supplied to the control electrode 7 respectively. For example, a recording density of 300 dots per inch (300d
In the case of recording by pi), if a switching element having 64 channels is used, five switching elements having 64 channels are required to control 300 openings.

Reference numerals 11a and 11b denote deflecting electrode voltage power supplies, which are connected to the deflecting electrodes 10a and 10b, respectively, and synchronize the voltage with a voltage pulse supplied from the control electrode voltage power supply 9 to deflect the deflecting electrodes. 10a and 10b.

Next, the insulating base material 1 of the toner passage control means 4
2 and a control electrode 7 provided on the
The configuration with b will be described with reference to FIG.

FIGS. 2A and 2B show toner passage control means 4.
FIG. 2A is a plan view showing a control electrode 7 and a toner passage hole 6 provided in the toner passage control means 4 on the toner carrier 2 side. FIG. 2B shows the toner passage control means 4 on the back electrode 3 side.
FIG. 3 is a plan view showing deflection electrodes 10a and 10b and a toner passage hole 6 provided in FIG.

Although the shape of each toner passage hole 6 shown in FIG. 2A is circular, it may be oval or elliptical. The diameter of the toner passage hole 6 is set to about 70 to 120 μm. In this embodiment, a circular toner passage hole 6 having a diameter of 90 μm is provided in the toner passage control unit 4. The shape of the control electrode 7 is a circle concentric with the toner passage hole 6, but may be an oval or an ellipse. Further, the control electrode 7 does not need to surround the entire periphery of the toner passage hole 6, and may be provided only on the upstream side or the downstream side in the rotation direction of the toner carrier 2. In this embodiment,
The toner passage hole 6 has a concentric shape, an inner diameter of 110 microns,
A control electrode with an outer diameter of 150 microns was used. Lead wire 15
Is provided on the toner passage control means 4 so as to connect the control electrode 7 and a voltage power supply for the control electrode. The voltage pulse generated by the control electrode voltage power supply is supplied to the control electrode 7 via the lead 15.

As shown in FIG. 2B, the deflection electrodes 10a and 10b are arranged obliquely with respect to the conveying direction of the image receiving member indicated by the arrow A with the toner passage hole 6 interposed therebetween. This is for causing the toner to sequentially fly in an oblique direction on the image receiving member being conveyed, thereby finally forming a horizontal line. Toner passage hole 6
Let l1 be a straight line passing through the center of the image receiving member and orthogonal to the conveying direction of the image receiving member, and let l2 be a straight line connecting the center of the deflection electrodes 10a and 10b in the length direction and the center of the toner passage hole. And l2 can be determined by the following equation.

Tan θ = 1 / N In the above equation, N is the number of toner trajectories obtained in the deflection process. For example, in the case shown in FIG. 7, three types of toner trajectories, left, center and right, are formed. Therefore, N = 3. In the present embodiment, as in FIG. 7, θ is set to 18.3 degrees in order to form three types of toner trajectories. The deflection electrodes 10a and 10b are shared by the adjacent toner passage holes 6.

FIG. 3 shows the control electrode 7 and the deflection electrode 10.
5A and 5B show the voltage waveforms applied to a and 10b and the flying direction of the toner corresponding thereto. That is, FIG. 3A is a time chart of the voltage waveform applied to the control electrode, and FIG.
(C) shows a time chart of voltage waveforms applied to the deflection electrodes 10a and 10b, respectively. FIGS. 3 (a) to 3 (c)
In the graph, the vertical axis represents voltage, and the horizontal axis represents time. FIG. 3D is a view showing a state in which the flying direction of the toner is sequentially deflected (see FIGS. 1 and 2).

In FIGS. 3A to 3C, T_tperiod
Indicates the time required to form one line, as described above.
This corresponds to the entire deflection process period. T_tIs the conveying direction of the image receiving member
Is determined by the resolution at. For example, 300d
To form horizontal lines at a pitch of pi (dot / inch)
Is 1 inch (inch) 25.4mm with 300 dots (Dot)
When divided, the line pitch becomes about 84.6 μm. One line
It is sufficient that the image receiving member moves by one pitch during the formation of.
Therefore, the speed of the image receiving member is, for example, 60 mm / s.
And T_tThe period is about 1390 μs. In this embodiment
Means that the resolution is 600 dpi and the conveying speed of the image receiving member is 10
0 mm / s. Therefore T_tThe period is 423 μs
You. Also, T_L, T_C, T_RSupplies a voltage to the control electrode 7
Supply of control voltage necessary to control the formation of one dot
Time, which corresponds to the above-described passage control step period. T _L
Is required to form one dot by the left deflection process
Control voltage supply time, T_C, T_RIs a straight running process, right deflection
Control electric power for forming one dot for each process
Pressure supply time.

[0060] In the present invention, long sets than the T _R on the other control voltage supply time. In the present embodiment, T _L = T _C = T
Set to satisfy _R / 2. That is, T _t = 423
μs, T _L = T _C ≒ 105.8 μs, T _R = 2
11.5 μs. Each control voltage supply time T _L ,
T _C, T _R is composed of a pulse voltage width T _B to facilitate the passage of the toner to the toner passage hole 6, a suppressor for suppressing time T _w the passage of toner into the toner passage hole 6. Pulse voltage width T _B corresponds to step promoting above. The pulse voltage width T _B is variable in accordance with an image signal supplied from the outside. That is, in the case of forming a low density dot is shorter T _B, at the time of high concentrations of dot formation is set longer T _B. Further, by setting T _B to zero, the toner cannot pass through the toner passage hole, so that a non-print area is formed. As a result, image formation with excellent gradation can be realized.

[0061] On the other hand, T _w indicates a period from after the end of the T _B to the next control voltage supply time. In the present embodiment, T
The variable range of _B was from 0 μs to 80 μs. Also,
During suppression periods T _w, a voltage V _w applied to the control electrode -1
And 00V, the pulse voltage V _c was set to 300V. In addition,
As described in Japanese Patent Application No. 10-75248 and drawings by the present applicant, a voltage pulse smaller than the voltage level at which the toner starts flying may be superimposed immediately after the start of each control voltage supply time. Good. Furthermore, and the voltage level V _w applied to the control electrode to suppress process period, voltage V _c that is added to the voltage level V _w in the period T _B is not limited to the above values,
An electric field for suppressing or promoting the passage of toner through the toner passage hole may be formed between the toner carrier and the toner passage control means. Further, in the present embodiment is applied to the control electrode of the suppression voltage V _w between the suppression period T _W, Set V _w to the ground level of the image forming apparatus, the toner and opposite polarity voltage to the toner carrier Is applied, it is possible to suppress the toner from passing through the toner passage hole during the _Tw period.

As shown in FIGS. 3B and 3C,
Each deflection electrode 10a, the voltage supply for the deflection electrode for supplying a deflection voltage to 10b is, V _L, three voltage levels of V _M, V _H are possible outputs, each deflection voltage levels, one dot control voltage Switch in synchronization with supply time. In the present embodiment, V
_L = -50V, and a _{V M = + 50V, V H} = + 120V. In this embodiment, the deflection voltage level is switched at the same time as the start of the control voltage supply time for one dot.
As described in Japanese Patent Application No. 11-52182 and drawings by the present applicant, the deflection voltage level may be switched after a delay from the start of the control voltage supply time.

Next, the overall operation of the image forming apparatus according to the present embodiment will be described with reference to FIGS.

First, the toner carrier 2 rotates, and the toner 1 is transported to a position facing the toner passage hole 6. The back electrode 3 has a voltage of +100 from the back electrode voltage power supply 8.
A voltage of 0 V is applied in advance. At this time, a voltage of −100 V is applied to the control electrode 7. As a result, the electric field formed between the toner carrier 2 and the back electrode 3 is cut off by the voltage supplied from the back electrode voltage power supply 8, so that the toner 1 is carried on the toner carrier 2. Becomes

Next, the image receiving member 5 is conveyed to a position facing the toner passage hole 6, that is, a print execution position. At the same time as the image receiving member 5 is conveyed to the print execution position, a predetermined pulse voltage as shown in FIG. 3 is selectively supplied from the control electrode voltage power supply 9 to the control electrode 7. Thereby, the toner carrier 2 is moved toward the control electrode 7 to which the pulse voltage is supplied.
The suction electric field by which the toner 1 above is sucked is applied to the toner carrier 2.
And the control electrode 7. The toner 1 detached from the toner carrier 2 by the above-mentioned suction electric field is further attracted by the electric field formed between the toner carrier 2 and the back electrode 3 and enters the toner passage hole 6.

A predetermined voltage is applied to the deflection electrodes 10a and 10b from the deflection electrode voltage power supplies 11a and 11b in synchronization with the pulse voltage applied to the control electrode 7. As a result, the flight trajectory of the toner 1 passing through the toner passage hole 6 is deflected by the deflecting electric field in the vicinity of the deflection electrodes 10a and 10b. After the flight trajectory is deflected, the toner is electrostatically attracted to the back electrode 3 and lands on the moving image receiving member 5 to form dots. The image receiving member 5 on which the dots are formed is conveyed to a fixing unit (not shown), and the image receiving member 5
The upper toner is heated and melted by the fixing unit, and is fixed on the image receiving member 5. After the fixing step, the image receiving member 5 is discharged out of the image forming apparatus, and a toner image fixed to the image receiving member 5 is finally obtained.

Next, the details of the operation of deflecting the flight trajectory of the toner will be described with reference to FIG.

First, in the passage control step corresponding to the control voltage supply time of _TL , the toner 1 detached from the toner carrier 2 by applying a pulse voltage to the control electrode 7 becomes a columnar shape and the toner passage hole 6 Pass through. At this time, the deflection electrode 1
The deflection voltage _VH is applied to 0a, and the deflection voltage _VL is applied to the deflection electrode 10b. Toner pillar 13 after passing through the toner passage hole 6 receives the electrostatic force F _Lb to repel the electrostatic force F _La and deflection electrode 10b is attracted to the deflection electrode 10a side. Also the voltage being applied to the back electrode 3, the toner pillar 13 is subjected to electrostatic force F _B which is attracted to the rear electrode 3. These electrostatic forces F _La , F _Lb ,
The resultant force of the F _B, trajectory of the toner pillar 13 is deflected, as shown in FIG. 3 (d), the flies tilted to the left,
The tip of the toner column 13 lands on the image receiving member 5.

Next, T_cControl voltage supply time
Move on to over control process. Apply to both deflection electrodes 10a and 10b
Voltage level is V_MSwitch to. At this time,
T_LToner flying in the passage control process corresponding to the period
The rear end of the column 13 has not landed on the image receiving member 5 yet. Yo
Thus, the deflection electrode 10 to which a voltage having a polarity opposite to that of the toner is applied.
Electrostatic force F sucked in the direction of b_CbBut the flight in flight
It acts on the rear end of the knurled column 13. Also, V_MBy applying
Electrostatic force F attracted to deflection electrode 10a_CaAt the same time
It acts on the toner column 13. Also, the back electrode 3 is
Since the same voltage as above is continuously applied, the toner
The column 13 has an electrostatic force F attracted to the back electrode 3._BReceiving
You. Therefore, the electrostatic force is applied to the rear end of the toner column 13 that has not landed.
F_Ca, F_Cb, F_BAnd the resultant force acts. However,
The distance between the rear end of the toner column 13 and the deflection electrode 10b is large.
The electrostatic attraction force F in the direction of the deflection electrode 10b_Cb
Is F_CaAnd F _BMuch smaller than. Therefore, undelivered
The rear end of the toner column 13 has almost electrostatic force F_CbAction
Without receiving it, as it is on the left side in FIG.
To land. On the other hand, a pulse voltage is applied to the control electrode 7 again.
Is done. As a result, the toner from the toner carrier 2
The toner is removed and becomes the next toner column 13 so that the toner passage hole 6 is formed.
pass. The same voltage is applied to the deflection electrodes 10a and 10b.
Is applied, the flight trajectory of the toner is deflected.
And not. Therefore, the toner column 13 moves toward the image receiving member 5.
It goes straight, and its tip tries to land on the image receiving member 5.

[0070] Turning now to passage control step corresponding to the control voltage supply time T _R. Deflection electrode 10a V the applied voltage level _L, and the voltage level applied to 10b switched to V _H. At this time, the rear end of the toner pillar 13 desorbed from the toner carrying member 2 in the step corresponding to front from T _C has not landed yet to the image receiving member 5. Therefore, it receives the electrostatic force F _Rb attracted to the deflection electrode 10b and the electrostatic force F _Ra repelling the deflection electrode 10a. Further, since the back electrode 3 it is continuously applied a voltage identical previous step, toner pillar 13 is subjected to electrostatic force F _B which is attracted to the rear electrode 3. Therefore the rear end of the non-impact of the toner pillar 13, the electrostatic force F _Ra, F _Rb, the resultant force of the F _B acts. However,
Since the distance between the rear end of the toner column 13 and the deflection electrode 10b is large, the electrostatic attraction force F _{Rb in} the direction of the deflection electrode 10b.
And the electrostatic repulsive force F _{Ra on the} deflection electrode 10a is much smaller than F _B. Therefore, the toner that has not landed is hardly affected by the electrostatic forces F _Ra and F _Rb and landed on the central portion in FIG. 3D as it is. On the other hand, a pulse voltage is applied to the control electrode 7 again. As a result, the toner is detached from the toner carrier 2 again, becomes a toner column, and passes through the toner passage hole 6. Deflection electrodes 10a, 10b
Since each voltage V _L, V _H is applied to the flying trajectory of the toner pillar is deflected towards the deflection electrode 10b. Passage control process of T _R are the double of the length of the other control processes, all of the toner lands on the image receiving member 5.

Next, again proceeds to steps T _L, the deflection voltage V _H is the deflection electrode 10a is, the deflecting electrode 10b but the deflection voltage V _L is applied, respectively, in this case, the T _R step If the toner column 13 whose deflection trajectory is deflected is located between the toner passage control means 4 and the back electrode 3 and does not reach the image receiving member 5, the toner column 13 will be attracted to the deflection electrode 10a by the electrostatic force F _La. And the electrostatic force _FLb repelling the deflection electrode 10b. Since the unlanded toner is close to the deflecting electrode 10b, the electrostatic repulsive force F _Lb largely acts on the unlanded toner, and as a result, the flight trajectory of the toner column 13 is deflected. As shown in (1), the toner lands on the image receiving member 5 toward the left and tries to cause a so-called tailing phenomenon. However, in the present invention,
Because all the toner pillar 13 in the process of T _R lands on the image receiving member 5, between the toner passing controller 4 and the back electrode 3, non-impact toner to cause tailing phenomenon does not exist. As a result, the tailing phenomenon is prevented.

Next, the printing speed of the image forming apparatus according to the embodiment of the present invention will be described in comparison with a conventional example with reference to FIG.

FIG. 4 is a time chart of voltage application to each electrode. 4A to 4C show time charts according to the present invention, and FIGS. 4D to 4F show time charts according to the conventional example. FIGS. 4A and 4D
Is a voltage pulse applied to the control electrode, (b) and (e) are deflection voltages applied to the deflection electrode 10a, and (c) and (f) are voltages applied to the deflection electrode 10b. The time chart of the deflection voltage is shown respectively.

In FIG. 4, T _t1 and T _t2 indicate the time required to form one line. The former indicates the present invention and the latter indicates the conventional example. Note that both correspond to the above-described entire deflection step period. T _L1 , T _C1 , and T _R1 denote control voltage supply times required to form one dot by the left deflection step, the straight movement step, and the right deflection step in the present invention, and T _L2 , T _{C 2} ,
T _R2 indicates the control voltage supply time required to form one dot by the left deflection step, the straight movement step, and the right deflection step in the conventional example. At this time, _TR2 indicates a limit time during which the tailing phenomenon does not occur. That is, if the control voltage supply time corresponding to the right deflection step is shorter than T _R2 , a tailing phenomenon occurs. Note that T _L1 , T _C1 , T _R1 and T _L2 , T _C2 , T _R2 correspond to the above-described passage control step period.

Further, as described above, in the dots formed through the left deflection process and the straight travel process, the trailing phenomenon of the toner hardly occurs. Therefore, the control voltage supply time corresponding to the left deflection step and the straight movement step indicated by T _L1 and T _C1 in FIG. 4A can be reduced as compared with the conventional example. In the present embodiment, T _L1 and T _C1 are set to half of the conventional T _L2 and T _C2 . On the other hand, the right deflection process, tailing phenomenon of the toner so prone, as shown by the T _R1 of FIG. 4 (a), equal to the prior art the same period T _R2.

By performing the above setting, in the present invention, the time T _t1 required to form one line can be reduced to ２ of T _t2 according to the conventional technique. This makes it possible to increase the printing speed by a factor of 1.5 compared to the prior art. In FIG. 4, T _L1 and T _C1 are set to be half those of the conventional T _L2 and T _C2 , but may be further reduced as long as the tailing phenomenon does not occur. However, since the allowable range of the voltage pulse width applied to the control electrode is also shortened at the same time, there is a possibility that the gradation of the dots printed on the image receiving member is inferior, as described above, T _R1 is T _L1 , It is preferable to set an integral multiple of T _C1 . If the supply of the voltage pulse is turned ON, ON, ON, and OFF in synchronization with one frequency, the supply start timing of the voltage pulse is always kept constant so that the voltage waveform shown in FIG. 4D is obtained. This is because you can do it.

The reason why it is preferable to set only the last control voltage supply time long in the entire deflection process cycle will be described with reference to FIG. In other words, FIG. 5 shows the case where the control voltage supply time of the dot formed last is set longer in the entire deflection process cycle and the case where the control voltage supply time of the dot formed first is set longer. FIGS. 5A and 5B are diagrams comparing the formation positions. FIGS. 5A and 5B are a time chart and a dot formation position when the control voltage supply time of the dot to be formed last is set longer.
(C) and (d) show a time chart and a dot formation position, respectively, when the control voltage supply time of the initially formed dots is set long.

Referring to FIG. 5, the process of forming dots will be described.
explain. First, the first control shown in FIGS. 5 (a) and 5 (c)
Voltage supply time T_LToner flies with the voltage pulse between
Starts, and the deflection electrode deflects the toner flight trajectory to the left.
After passing through the steps, ₁Is formed at the position. Next
Control voltage supply time T_CThe voltage pulse between
Starts flying, and the toner flight trajectory goes straight by the deflection electrode
After the process, the dot is_TwoFormed in the position
Is done. C_TwoUntil a dot is formed at the position₁
The dot formed at the position is carried and conveyed by the image receiving member,
L_TwoMove to the position. Last control voltage supply time T_Rof
With the voltage pulse between, the toner starts flying and the deflection electrode
After the process of deflecting the toner flight trajectory to the right by
Dot is R _ThreeIs formed at the position. R_ThreeDot at position
Until formed, L_Two, C_TwoFormed in the position of
Each dot is carried and conveyed to the image receiving member, and_Three, C_ThreeRank
Move to the position.

When the position of the dot formed by the above process is set to be longer than the last control voltage supply time,
The comparison is made below (see FIG. 5B) and when the first control voltage supply time is set long (see FIG. 5D).

[0080] In the former case, so that L ₂ is conveyed to the next pre-dot position, by setting the image receiving member conveying speed and TL, since the control voltage supply time T _L and T _c is equal to, L
The travel distance from ₂ to L ₃ or C ₂ to C ₃ is L ₁
Equal to the moving distance to the L ₂ from. As a result, L ₃ ,
The dot positions of C ₃ and R ₃ are arranged in a horizontal line, and a smooth horizontal line is formed.

On the other hand, in the latter case, since the control voltage supply time T _L is longer than T _c , the moving distance from L ₁ to L ₂ is the moving distance from L ₂ to L ₃ or the moving distance from C ₂ to C _3. Be longer. As a result, the dot positions of L ₃ , C ₃ , and R ₃ are not arranged in a horizontal line, and a smooth horizontal line cannot be formed. As described above, by leaving equal last control voltage supply time T _R other control voltage supply time with the exception of T _L, a T _C, smooth horizontal lines can be formed.

In the above-described embodiment, the deflection process is performed in three types: the left deflection process, the straight traveling process, and the right deflection process. However, the number of deflection processes may be further increased. By increasing the number of deflection steps for deflecting the flight trajectory of the toner in a direction perpendicular to the moving direction of the image receiving member, an image with high resolution can be printed. However, since the value obtained by dividing the entire cycle of the deflection process by the number of deflection processes is the pass control process for one dot, the period of the pass control process is shortened as the number of deflection processes increases.
For this reason, the range in which the promotion process for promoting the passage of the toner through the toner passage hole is narrowed, and the gradation number of the printed image is reduced.

In the above-described embodiment, the flying trajectory of each toner is deflected so that the dots formed by the deflecting process within the entire deflecting process cycle are aligned in a direction orthogonal to the traveling direction of the image receiving member. However, the present invention is not limited to this. For example, in order to improve the resolution of an image viewed in the traveling direction of the image receiving member, the dots formed by the deflecting process within the entire deflecting process cycle are arranged in a line along the traveling direction of the image receiving member. The flight trajectory may be deflected.

In the above embodiment, the trajectory of the toner is deflected by applying a deflecting voltage to the deflecting electrode and forming a deflecting electric field between the toner passage control means and the image receiving member. The present invention is not limited to this. For example, it is a matter of course that a deflection magnetic pole that forms a deflection magnetic field instead of a deflection electric field using a magnetic toner containing magnetic powder may be provided.

[0085]

As described above, the image forming method according to the first aspect of the present invention is an image forming method including a transporting step, a passage controlling step, a deflecting step, and a landing step.
The passage control process for one dot includes a promotion process for promoting the passage of the developer through the developer passage hole and a suppression process for suppressing the passage of the developer through the developer passage hole, and is formed by a continuous landing process. As the distance between the two dots becomes longer, the period of the suppression step that contributes to the dot formed earlier of the two dots is made longer. According to the method of the present invention, under the condition that the distance between two dots continuously formed on the image receiving member increases, all the developer that has been flying before lands on the image receiving member, or When the flight trajectory reaches a position that is not affected by the deflection electric field, the developer before landing, which causes the tailing phenomenon, does not remain between the developer passage hole and the image receiving member. The phenomenon can be prevented.

According to the second aspect of the present invention, the amount of the developer passing through the developer passage control means can be adjusted by making the period of the acceleration step variable according to an external image signal. The dot density formed on the image receiving member can be reproduced in multiple gradations.

According to the third aspect of the present invention, the length of each pass control process period is an integral multiple of the shortest pass control process period. Since the acceleration step can be started, a plurality of frequency oscillating means are not required.

According to the fourth aspect of the present invention, the dots formed by the developer that has landed on the image receiving member sequentially from the same developer passage hole through the deflecting step are D ₁ , D ₂ ,..., D _n (n is 3
Together is formed on the image receiving member repeatedly in the order of an integer greater than one), the period T _1, T ₂ of the passage control step, ..., T _n is the formula _{T 1 = T 2 = ... =} T n-1 <T n By satisfying the condition, the printing speed is increased, and at the same time, the images are arranged in a line in a direction orthogonal to the image receiving member transport direction, so that a smooth horizontal line image can be formed.

According to the image forming apparatus of the present invention,
A developer carrier, an image receiving member, a developer passage control unit,
An image forming apparatus having a control electrode and a supply unit for a control voltage and a deflection voltage, wherein the control voltage supply unit increases a difference between two deflection voltage levels continuously supplied to the deflection electrode. By adjusting the control voltage supply time so that the control voltage supply time corresponding to the deflection voltage applied to the control electrode before one of the two deflection voltage levels becomes longer, the dots formed earlier 2. The same operation as in claim 1 under the condition that the control voltage supply time corresponding to the condition (1) becomes longer and the distance between two dots continuously formed on the image receiving member becomes longer, which is the condition that the tailing phenomenon is likely to occur. The effect can be obtained.

According to the sixth aspect of the present invention, the control voltage of the control voltage supply means includes an accelerating voltage for promoting the passage of the developer through the developer passage hole and a suppression voltage for suppressing the passage of the developer through the developer passage hole. The application time of the accelerating voltage is adjusted according to the image signal from the outside,
The same function and effect as the second aspect of the invention can be obtained.

According to the seventh aspect of the invention, the control voltage supply time is set to an integral multiple of the shortest control voltage supply time, so that the same operation and effect as the third aspect of the invention can be obtained.

According to the eighth aspect of the present invention, the dots that fly from the same developer passage hole, pass near the deflection electrode, and are sequentially formed by the developer landed on the image receiving member are D ₁ , D ₂ , and D ₁ .
.., D _n (n is an integer of 3 or more) so that the voltage level supplied to the deflection voltage by the deflection voltage supply means is sequentially switched so that dots are formed on the image receiving member, and the control voltage is supplied. The times T ₁ , T ₂ ,..., T _n are given by the equation T ₁ =
By controlling the control voltage supply time by the control voltage supply means so as to satisfy T ₂ =... = T _n-1 <T _n , the same operation and effect as the invention of claim 4 can be obtained. Can be.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of a surface on a toner carrier side and a surface on a back electrode side of the toner passage control unit according to the embodiment of the present invention.

FIG. 3 is a diagram showing a voltage waveform applied to a control electrode and a deflection electrode, and a state in which a flying direction of toner is sequentially deflected in the embodiment of the present invention.

FIG. 4 is a time chart showing a voltage waveform applied to a control electrode and a deflection electrode in an embodiment of the present invention, as compared with a conventional example.

FIG. 5 is a time chart for a case where the formation time of a dot to be formed last is set to be long and a case where the formation time of a dot to be formed first is set to be long;

FIG. 6 is a schematic sectional view showing a conventional image forming apparatus.

FIG. 7 is a diagram illustrating a state of deflection, a direction of deflection, and voltages applied to control electrodes and deflection electrodes in a conventional image forming apparatus.

FIG. 8 is a diagram illustrating a state of a line image in which a tailing phenomenon has occurred.

FIG. 9 is a diagram illustrating the principle of generation of the tailing phenomenon for explaining the principle of generation of the tailing phenomenon.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Toner 2 Toner carrier 3 Back electrode 4 Toner passage control means 5 Image receiving member 6 Toner passage hole 7 Control electrode 8 Voltage power supply for back electrode 9 Voltage power supply for control electrode 10a, 10b Deflection electrode 11a, 11b Voltage power supply for deflection electrode 12 Insulating base material 13 Toner pillar 14 Cover film 15 Lead wire

 ────────────────────────────────────────────────── ─── Continuation of the front page (71) Applicant 597063831 Owneds Brygga 13 421 57 Vestro Froland a Sweden (72) Inventor Yoshitaka Kitaoka 1006 Odakadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Masahiro Aizawa 1006, Kazuma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F-term (reference) 2C162 AE13 AE25 AE31 AE47 AE74 AE79 AE83 AE86 AF13 AF19 AF70 AF72 AH03 AH15 AH19 CA02 CA12 CA24

Claims (8)

[Claims] A transporting step of transporting the developer by supporting the developer on a developer carrying member; and, among the developers transported in the transporting step, facing a plurality of developer passage holes of a developer passage control unit. A passage control step of sequentially controlling passage of the developer conveyed to the position through the developer passage hole; and synchronizing a flight trajectory of the developer sequentially passing through the same developer passage hole with the passage control step in the passage control step. And a landing step of sequentially landing on the image receiving member the developers sequentially deflected to different flight trajectories by the deflection step, respectively. The passage control step includes: a promotion step of promoting the passage of the developer through the developer passage hole in response to an external image signal; and a suppression step of suppressing the passage of the developer through the developer passage hole immediately after the promotion step. Composed of The longer the distance between two dots formed by successive landing steps, the longer the period of the suppression step in the passage control step that contributes to the dot formed earlier of the two dots. Image forming method. 2. The image forming method according to claim 1, wherein a period of the promotion step is variable according to an external image signal. 3. The image forming method according to claim 1, wherein the length of each pass control step period is an integral multiple of the shortest pass control step period. 4. The same dots formed by developer sequentially landed on the image receiving member through the deflection step from the developer passage hole D _1, D _2, ..., and D _n (n is an integer of 3 or more), D ₁ from D _n periods contributes passage control step for formation of dots to T _1, T _2, ..., When _{T n, D 1, D 2} , ..., on repeated image receiving member in the order of D _n Forming a dot and formula T
_{1 = T 2 = ... = T} n-1 < Image forming method according to any one of claims 1 to 3 and satisfies the T _n. 5. A developer carrying member for carrying and transporting a developer, an image receiving member provided to face the developer carrying member and receiving a developer image, and between the developer carrying member and the image receiving member. A developer passage control unit provided with a plurality of developer passage holes through which the developer carried by the developer carrier passes toward the image receiving member; and a control arranged around each of the developer passage holes. An electrode, and a control voltage for controlling passage of a developer through a developer passage hole in accordance with an external image signal to the control electrode for a specific period in order to form one dot on the image receiving member. A control voltage supply unit, a deflection electrode disposed around each of the developer passage holes, for deflecting a flight trajectory of the developer from the developer passage control unit to the image receiving member, and a deflection voltage synchronized with the control voltage. Turn off the supplied voltage level A control voltage supply unit, wherein the control voltage supply unit changes the two deflection voltage levels as the difference between the two deflection voltage levels continuously supplied to the deflection electrode increases. Wherein the control voltage supply time is adjusted so that the control voltage supply time corresponding to the deflection voltage applied to the control electrode before becomes longer. 6. The control voltage of the control voltage supply means includes an accelerating voltage for accelerating the passage of the developer through the developer passage hole and a suppression voltage for suppressing the passage of the developer through the developer passage hole. 6. The image forming apparatus according to claim 5, wherein an application time of the acceleration voltage is adjusted according to an external image signal. 7. The image forming apparatus according to claim 5, wherein each of the control voltage supply times is an integral multiple of the shortest control voltage supply time. 8. same flies from the developer passage hole passing through the vicinity of the deflection electrodes, the sequentially formed dots with a developer that has landed on the receiving member _{D 1, D 2, ...,} D n (n is 3 more integer), and contributing control voltage supply time for formation of dots from D ₁ to _{D n T 1, T 2,} ..., When T _n, D _1,
The voltage level supplied to the deflection voltage by the deflection voltage supply means is sequentially switched so that dots are repeatedly formed on the image receiving member in the order of D ₂ ,..., D _n , and the equation T ₁ = T ₂ =. = T _n-1 <T _n , wherein the control voltage supply means adjusts the control voltage supply time so as to satisfy T _n-1 <T _n . Image forming device.