JP2003291391A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus in which a toner image having a good image quality can be formed stably by controlling deformation of a gap regulating means at a position touching a toner layer thereby sustaining a uniform touching pressure between the toner layer and the gap regulating means. <P>SOLUTION: The gap GP is kept constant by providing a spacer 5 touching a toner layer TL on a developing roller 12 on an FPC 4. The spacer 5 is bonded to the FPC 4 only at the other end 59 on the side opposite to the side end part 58 touching the toner layer TL and a rod-like spacer reinforcing rib 55 extending in the widthwise direction X is provided on the surface of the spacer 5 between the other end 59 and the touching side end part 58. Consequently, the spacer 5 is hard to be bent in the X direction and deformation at the end part 59 due to waving of the FPC 4 or uneven thickness of an adhesive layer 60 does not extend to the touching side end part 58. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile and a printer, and more particularly to copying paper, transfer paper, copying paper and recording paper by controlling the toner flying from the toner carrier to the back electrode. The present invention relates to an image forming apparatus that forms an image by attaching toner to an image receiving body such as a transfer medium.

[0002]

2. Description of the Related Art As an image forming method using toner,
Conventionally, the jumping type and the projection type have been most widely used. In this type of image forming method, an electrostatic latent image corresponding to an image is formed on a photoconductor, and toner as an image forming agent is adhered to the electrostatic latent image on the photoconductor from a toner carrier such as a developing roller. To obtain a toner image, and then transfer the toner image to copy paper, transfer paper, copy paper,
It is to be transferred onto recording paper. However, these image forming methods require a step (photosensitive process) of forming an electrostatic latent image on the surface of the photoconductor, which involves a problem that the apparatus configuration is complicated and the apparatus cost and running cost are high. There is. Therefore, in recent years, as described in U.S. Pat. Nos. 3,689,935 and 5,036,341 and Japanese Patent Laid-Open No. 2001-505146, toner is copied by a function of an electric field, recording paper or intermediate paper. An image forming apparatus of a so-called "toner jet (registered trademark)" system, which forms an image by flying on an image receiving body such as a transfer belt, has been attracting attention.

In this image forming apparatus, a flexible printed circuit board (Flexible Printed Circu) having a plurality of toner passage holes for passing charged toner between a toner carrier for carrying and carrying charged toner and the back electrode.
It) is arranged, and further an image receiver such as a recording paper or a transfer medium is arranged between the flexible printed circuit board and the back electrode. Then, a potential difference is applied between the toner carrier and the back electrode to form a transfer electrostatic field that causes the charged toner to fly from the toner carrier to the back electrode. Further, in the flexible printed circuit board, control electrodes are arranged around each toner passage hole, and each toner passage hole is electrostatically opened and closed by controlling the voltage applied to each control electrode according to the image signal, Corresponding to the image signal, the charged toner is caused to fly from the toner carrier to the back electrode through the toner passage hole and adhere to the image receiver. By doing so, a toner image corresponding to the image signal is formed on the image receiving body.

In such an image forming apparatus, it is necessary to increase the electric field strength of the transfer electrostatic field in order to fly a sufficient amount of charged toner for forming a toner image.
Since a very high voltage cannot be applied to the control electrode due to the device configuration, it is desirable to make the gap as small as possible in order to obtain a sufficient electric field strength. Further, in order to stably form a toner image, it is necessary to keep the gap between the toner carrier and the control electrode constant. Therefore, there has been proposed a gap management technique for keeping the gap constant by disposing a spacer (gap defining means) having a thickness of several μm to several tens μm between the toner carrier and the flexible printed circuit board.

For example, in Japanese Unexamined Patent Publication No. 2000-355115, a spacer is provided which contacts a toner layer formed on a toner carrier, and the width of the spacer in the direction orthogonal to the moving direction of the toner carrier is defined as the width of the toner layer. An image forming apparatus having a width larger than the width is disclosed. Further, it is described that with such a configuration, it is possible to prevent the end portion of the spacer contacting the toner layer from disturbing the uniformity of the toner layer on the toner carrier, and to perform stable image formation. .

[0006]

By the way, as described above, it is desirable to make the spacer as thin as possible. However, the spacer formed so thin is easily deformed. In particular, in an apparatus having a structure in which the spacer is attached to the surface of the flexible printed board, the spacer may be deformed by attaching the spacer to the flexible printed board. For example, when the spacer is brought into close contact with the surface of the flexible printed board, the spacer may be deformed by picking up irregularities due to corrugation or the like on the surface of the board. Further, for example, when both are attached by adhesion, if the thickness of the adhesive layer is uneven, the spacer is deformed correspondingly.

However, in the above-mentioned prior art apparatus, the deformation of the spacer (gap defining means) caused by the waving of the flexible printed circuit board (toner flying control means) or the mounting method of the spacer is taken into consideration. However, when the spacer thus deformed contacts the toner layer on the toner carrier, a non-uniform force is applied to each toner particle forming the toner layer depending on the position, and as a result, the toner layer There is a problem in that the uniformity deteriorates and the image quality deteriorates.

The present invention has been made in view of the above problems, and suppresses the deformation of the gap defining means at the contact position with the toner layer to uniformly maintain the contact pressure between the toner layer and the gap defining means. An object of the present invention is to provide an image forming apparatus capable of forming a stable toner image with good image quality.

[0009]

In order to achieve the above object, an image forming apparatus according to the present invention carries a charged toner and moves the toner in a predetermined moving direction so that the toner reaches a toner flying start position. A toner carrier to be conveyed, a back electrode arranged so as to face the toner flying start position of the toner carrier, and a back electrode arranged between the toner carrier and the back electrode. A toner flying control means for forming a toner image by landing toner on an image receiving body conveyed between the back electrode and the back electrode by controlling toner flying to the back electrode, and a direction orthogonal to the moving direction of the toner carrier. The toner carrier and the toner flying control are inserted between the toner layer carried on the toner carrier and the toner flying control means. A gap defining means for defining a gap between the means and the gap defining means, wherein the gap defining means is provided on the side opposite to the toner flying start position with respect to one end of the gap defining means that abuts the toner layer. It is characterized in that it is provided with a deformation suppressing member for suppressing the deformation of the gap defining means in the width direction.

In the invention thus constructed, the deformation regulating member is provided in the gap defining means in order to suppress the deformation of the thin gap defining means. Therefore, at the contact position with the toner layer, the gap defining means is kept flat without being deformed, and the pressure exerted by the contact of the gap defining means with each toner particle forming the toner layer, that is, the contact force The contact pressure is substantially uniform within the image forming range in the width direction. Therefore, in this image forming apparatus, the uniformity of the toner layer conveyed to the toner flying start position is maintained, and as a result, a stable toner image with good image quality can be formed.

Further, in order to stably form a toner image having a good image quality, it is necessary to make the gap between the toner carrier and the toner flying control means extremely small and uniform. In view of this, in the present invention, the deformation suppressing member provided in the gap defining means is arranged at a position farther from one end contacting the toner layer when viewed from the toner flying start position. Therefore, it is possible to form one end of the gap defining means that comes into contact with the toner layer to be extremely thin, and to effectively suppress the deformation thereof. By doing so, the gap can be kept small and uniform, It is possible to form a stable toner image.

Further, the gap defining means may be fixed to the toner flying control means at the other end opposite to the one end contacting the toner layer. In this case, the deformation suppressing member is arranged between the other end of the gap defining means fixed to the toner flying control means and the one end in contact with the toner layer. Even if the other end portion is deformed due to the unevenness of the surface of the toner flying control means adhered to the toner layer or the unevenness of the thickness of the adhesive layer, the deformation does not affect the one end portion contacting the toner layer. Without this one end can be kept flat.

Such a deformation suppressing member may be a suppressing member that abuts on the gap defining means at an abutting portion extending in the width direction between the one end and the other end of the gap defining means. Good. Further, it is preferable that the deformation suppressing member has a flexural rigidity in the width direction larger than that of the toner flying control means.

The image forming apparatus according to the present invention is
In order to achieve the above object, a toner carrier that carries a charged toner and moves the toner in a predetermined moving direction to a toner flying start position, and a toner carrier at the toner flying start position of the toner carrier. The back electrode is disposed so as to face each other, and is disposed between the toner carrier and the back electrode, and the distance between the back electrode and the back electrode is controlled by controlling the toner flying from the toner carrier to the back electrode. Toner flight control means for forming a toner image by landing toner on a conveyed image receiving body, and toner carried on the toner carrying body extending in a width direction orthogonal to the moving direction of the toner carrying body. A gap defining means that is interposed between a layer and the toner flying control means and defines a gap between the toner carrier and the toner flying control means. The gap defining means is integrally formed with the gap defining means on the side opposite to the toner flying start position with respect to one end of the gap defining means that is in contact with the toner layer, and the width of the gap defining means. It is characterized in that a deformation suppressing portion for suppressing deformation in the direction is provided.

In the invention thus constructed, the deformation suppressing portion formed integrally with the gap defining means prevents deformation of the gap defining means in the width direction, like the deformation suppressing member in the above apparatus. Therefore, the uniformity of the toner layer conveyed to the toner flying start position is maintained, and as a result, a stable toner image with good image quality can be formed. Further, by providing the deformation suppressing portion integrally with the gap defining means, it is possible to reduce the number of parts and simplify the device structure, and to make the deformation suppressing effect more reliable.

Such a deformation suppressing portion can be constructed by making the shape of the gap defining means as follows. For example, the gap defining means is formed in a thin plate shape and includes a thin portion including the one end portion, and is integrally formed with the thin portion, and the gap direction is defined between the one end portion and the other end portion. By forming the gap defining means in a direction orthogonal to the width direction to have a thick portion formed by increasing the thickness from the thin portion, the thick portion having higher bending strength in the width direction. Can be made to function as the deformation suppressing portion.

Further, for example, the gap defining means is
By forming the bent portion along at least one location along a straight line substantially parallel to the width direction into a thin plate shape, the bent portion can function as the deformation suppressing portion.
This is because bending the gap defining means in this manner makes it difficult for the gap defining means to bend in the width direction.

Further, the gap defining means may be provided on either the upstream side or the downstream side in the moving direction of the toner carrier with respect to the toner flying start position. Among them, in the structure in which the gap defining means is provided on the upstream side, the toner layer in contact with the gap defining means is conveyed to the toner flying start position, so that the non-uniform contact pressure causes variations in the flying property of each toner particle. This immediately causes deterioration of image quality such as image unevenness. On the other hand, in the configuration in which the gap defining means is provided on the downstream side, the toner particles are pressed against the toner carrier by a non-uniform force, which causes non-uniformity in the subsequent toner removal from the toner carrier and the reforming process of the toner layer. Occurs, and it becomes impossible to stably form a uniform toner layer on the toner carrier,
After all, the image quality will deteriorate.

Therefore, in any of the configurations, in order to improve the uniformity of the contact pressure between the gap defining means and the toner layer, the gap defining means is provided with the deformation suppressing portion as described above, so that image quality and image formation are improved. The stability can be improved.

[0020]

1 is a diagram showing an embodiment of an image forming apparatus according to the present invention. 2 is a block diagram showing an electrical configuration of the image forming apparatus of FIG. In this image forming apparatus, when an image signal is given to the main controller 101 of the control unit 100 from an external device such as a host computer, the main controller 1
The engine controller 102 controls each part of the developing device 1 in accordance with a signal from 01, so that the two rollers 21,
The toner flies and adheres to the intermediate transfer belt 23 that is stretched around the sheet 22 to form a toner image corresponding to the image signal. Thus, in this embodiment, the intermediate transfer belt 23
Is functioning as an image receiver.

In this developing device 1, in the housing 11,
The toner T as a developer is stored, and the developing roller 12, the supply roller 13, and the regulation blade 14 are housed. The developing roller 12 carries charged toner (that is, charged particles for image formation) T, and rotates at a predetermined peripheral speed in the direction of arrow D in FIG. Flight start position) J
It is a toner carrier to be transported to. This developing roller 12
Is formed in a cylindrical shape with a metal or alloy such as aluminum or iron, and a DC voltage is applied from the developing roller bias generator 103 provided in the engine controller 102.

The supply roller 13 is brought into contact with the outer peripheral surface of the developing roller 12 and rotates in the opposite direction to the developing roller 12,
The toner T is supplied to the developing roller 12 and the excess toner T is dropped from the developing roller 12. The supply roller 13 is made of, for example, a metal core wrapped with synthetic rubber such as urethane sponge, and also has a function of charging the toner T to a predetermined polarity by frictionally contacting the developing roller 12. In the present embodiment, the toner T will be described below as being negatively charged.

The regulation blade 14 is applied to the outer peripheral surface of the developing roller 12 on the downstream side of the supply roller 13 in the rotation direction D of the developing roller 12, and the toner T is negatively charged by friction with the developing roller 12. The amount of toner T carried on the developing roller 12 is regulated. More specifically, the regulation blade 14 is constituted by a plate-shaped metal piece 141 having one end fixed to the housing 11, and an elastic member 142 attached to the other end of the plate-shaped metal piece 141. Contact the surface, toner T
Are regulated.

The back electrode 3 is opposed to the developing roller 12.
Are arranged. More specifically, the back electrode 3 is shown in FIG.
As shown in FIG. 3, the intermediate transfer belt 23 is sandwiched between the developing roller 12 and the developing roller 12. The back bias generator 104 provided in the engine controller 102
Therefore, a DC voltage higher than the voltage applied to the developing roller 12 is applied, and a transfer electrostatic field for transferring the charged toner T toward the back electrode 3 is applied between the developing roller 12 and the back electrode 3. Has been formed. For this reason, the charged electrostatic toner T at the toner flying start position J is generated by the transfer electrostatic field.
Flies from the developing roller 12 toward the back electrode 3 and is deposited and attached to the surface of the intermediate transfer belt 23 that functions as an image receiver.

Further, in this embodiment, in order to control the flight of the charged toner T onto the intermediate transfer belt 23, a flexible printed circuit board (hereinafter referred to as FPC) 4 is provided between the developing roller 12 and the back electrode 3. It is arranged. Hereinafter, the configuration and operation of the FPC 4 will be described with reference to FIGS. 3 and 4.

FIG. 3 is a diagram showing a partially enlarged cross section of a flexible printed circuit board and a flying model of charged toner. Further, FIG. 4 is a view showing control electrodes and deflection electrodes formed on the flexible printed circuit board. This F
In the PC 4, a toner passage hole 41 for guiding the charged toner T from the developing roller 12 to the back electrode 3 is formed in a base 42 made of an electrically insulating material such as polyimide.
Although only one toner passage hole 41 is shown in FIG. 3, in this embodiment, a plurality of toner passage holes 41 are provided in a line in the direction perpendicular to the plane of FIG. The charged toner T can pass through the toner passage holes 41 toward the back electrode 3 side. Although the toner passage holes 41 are arranged in one row in this embodiment, they may be arranged in plural rows. Further, the shape of the toner passage hole 41 may be circular as in this embodiment, or may be elliptical or polygonal.

On the developing roller 12 side of the base 42, a control electrode 43 is formed in a ring shape so as to surround each toner passage hole 41. In addition, each control electrode 43
The lead wire 44 extends in the direction orthogonal to the arrangement direction of the toner passage holes 41. The shape of the control electrode 43 is not limited to the circular shape, but may be any shape, and may be, for example, an elliptical shape or a polygonal shape. Further, the control electrode 43 may have a partial cutout instead of a perfect ring. .

On the back electrode 3 side of the base 42,
A pair of deflection electrodes 45L, 4L is provided for each toner passage hole 41.
As shown in FIG. 4, 5R is provided so as to be diagonally opposed to the conveyance direction Y of the intermediate transfer belt 23 (direction orthogonal to the toner passage hole array), and the deflection electrodes 45L, 4L,
Lead wires 46L and 46R are extended from 5R, respectively.

Although not shown in FIGS. 3 and 4, the base 42 has a control bias generator 47 (FIG. 2) and an L deflection bias generator 48L (FIG. 2), which are high voltage driver ICs and the like. And R deflection bias generator 48
R (FIG. 2) is provided. Of these, the control bias generator 47 is electrically connected to each control electrode 43, and an appropriate voltage is selectively applied according to an opening / closing control signal from the CPU 105 of the engine controller 102, whereby the toner is discharged. The passage hole 41 is opened and closed electrostatically. That is, for each control electrode 43, the charged toner T is ejected from the developing roller 12, passes through the toner passage hole 41, and is ejected toward the back electrode 3, so that the toner is between the developing roller 12 and the back electrode 3. It exposes the transfer electrostatic field passing through the passage hole 41 and limits the exposure.

The L deflection bias generator 48L is electrically connected to the deflection electrode 45L, and the R deflection bias generator 48R is electrically connected to the deflection electrode 45R. The engine controller 102 controls deflection. By appropriately applying an appropriate voltage to each of the deflection electrodes 45L and 45R according to the signal, the charged toner T
The flight direction of is switched to the following three directions.

(1) No deflection: When the same voltage is applied to both deflection electrodes 45L and 45R of arrow P1 in FIG. 3, the charged toner T is charged with the toner passage hole 41 as shown by arrow P1 in FIG. Straight through the intermediate transfer belt 23
And fly to a position corresponding to the toner passage hole 41 on the above.

(2) Leftward deflection: Among the deflection electrodes 45L and 45R indicated by the arrow P2 in FIG. 3, the deflection electrode 45L disposed on the left side of the toner passage hole 41 on the right side with respect to the conveyance direction Y of the intermediate transfer belt 23 is on the right side. Deflection electrode 45 arranged
When a voltage relatively higher than R is applied, the charged toner T charged in the negative polarity has a static charge for deflection generated between the electrodes 45L and 45R as shown by an arrow P2 in FIG. It is deflected to the left by the electric field.

(3) Right deflection: Among the deflection electrodes 45L and 45R indicated by the arrow P3 in FIG. 3, the deflection electrode 45R disposed on the right side of the toner passage hole 41 on the left side with respect to the conveyance direction Y of the intermediate transfer belt 23 is on the left side. Deflection electrode 45 arranged
When a voltage relatively higher than L is applied, the charged toner T, which is negatively charged, is deflected statically between the electrodes 45L and 45R as shown by the arrow P3 in FIG. It is deflected to the right by the electric field.

As described above, in this embodiment, the flying direction of the charged toner T is switched to the three directions, and the charged toner T is landed on the intermediate transfer belt 23 at the landing position PI of the intermediate transfer belt 23 including the deflection range. I am letting you.

However, as described above, the deflection electrodes 45L, 45
Since R is diagonally opposed to the transport direction Y of the intermediary transfer belt 23, the intermediary transfer belt 23 is formed by the three modes of (1) no deflection, (2) left deflection, and (3) right deflection. When 23 is stopped, the intermediate transfer belt 23
On the intermediate transfer belt 23, three dots lined up obliquely with respect to the transport direction Y of. In this case, the transport speed is determined so that the intermediate transfer belt 23 is transported by the displacement amount (distance) of the adjacent dots in the cycle (time) of hitting the dots, so that the three dots are transferred to the intermediate transfer belt 23. They can be arranged linearly in the direction orthogonal to the transport direction Y. Therefore, three dots can be formed with one toner passage hole 41, and the density of the dots can be increased.

In the base 42 of the FPC 4, the developing roller 12
On the surface 421 on the side and the surface 422 on the side of the back electrode 3, a semiconductive layer 49 for antistatic is formed and a ground potential is given. These semi-conductive layers 4
Reference numeral 9 indicates an optimum resistance value at a preset temperature (initial setting temperature). The frictional charge generated when the charged toner T flying as described above comes into contact with the FPC 4 is indicated by the FPC 4
The FPC 4 can be effectively prevented from being discharged from the above, and the influence on the electrostatic transfer field and the deflection electric field can be suppressed. That is, good print quality can be ensured while the temperature of the semiconductive layer 49 is maintained within the initial set temperature or the allowable temperature range.

Further, on the upstream side of the toner flying start position J in the rotation direction D of the developing roller 12, between the FPC 4 and the developing roller 12 configured as described above, the longitudinal direction of the developing roller 12 (see FIG. 3). Direction), that is, the spacer 5 spread in the width direction X of the developing roller 12 is inserted in the front side in the rotation direction D with respect to the toner passage hole 41 of the FPC 4, and a part of the spacer 5 is formed.
The gap GP between the developing roller 12 and the toner passage hole 41 of the FPC 4 is regulated to a constant value by coming into contact with the toner layer TL carried on the sheet 2. Thus, in this embodiment, the spacer 5 functions as a gap defining means.

Spacer reinforcing ribs 55 for suppressing deformation of the spacers 5 in the width direction X are provided on the main surface of the spacer 5 opposite to the FPC 4. The spacer reinforcing ribs 55 will be described later in detail. I will describe.

In the image forming apparatus configured as described above, when an image signal is given from the external device to the main controller 101 of the control unit 100, the CPU 105 of the engine controller 102 responds to the signal from the main controller 101. Applies a control signal corresponding to the image signal to the control bias generation unit 47, the L deflection bias generation unit 48L and the R deflection bias generation unit 48R to cause the toner T to fly and adhere onto the intermediate transfer belt 23 to correspond to the image signal. The formed toner image is formed. Then, the toner image is transferred onto a sheet S such as a copy sheet, a transfer sheet, and an OHP transparent sheet taken out from the cassette 7 in a predetermined transfer region TR. Further, the sheet S on which the image is thus formed is conveyed to the discharge tray (not shown) via the fixing unit 8.

Next, the structure and action of the spacer reinforcing rib 55 will be described with reference to FIGS. FIG. 5 is a view showing the spacer 5 and the spacer reinforcing rib 55 in this image forming apparatus, and FIG. 6 is a view showing a state in which the spacer 5 is attached to the FPC 4. Further, FIG. 7 is a diagram for explaining the operation of the spacer reinforcing rib 55 in this image forming apparatus.

As shown in FIG. 5, the spacer reinforcing rib 55 is formed in a rectangular rod shape in cross section so that the bending rigidity in the length direction thereof is larger than the bending rigidity in the width direction X of the FPC 4. Is configured. For the FPC 4 whose base body 42 is made of a resin material such as polyimide, a spacer reinforcing rib 55 is provided.
For example, a metal material such as brass or stainless steel, a resin material such as epoxy, or a ceramic material can be used.

The length of the spacer reinforcing rib 55 is formed to be substantially the same as the width of the spacer 5. The spacer reinforcing ribs 55 are fixed to the main surface of the spacer 5 opposite to the FPC 4 substantially in parallel with the width direction X of the spacer 5.

As shown in FIG. 6, the spacer 5 and the spacer reinforcing rib 55 are integrally bonded to the surface of the FPC 4 on the side of the developing roller 12 on the upstream side of the toner flying start position J in the toner transport direction D. ing. Here, the spacer 5 is not adhered to the FPC 4 over the entire surface thereof, but only the upstream side other end portion 59 opposite to the one end portion 58 of the spacer 5 in contact with the toner layer TL on the developing roller 12. The adhesive 60 is applied to the FPC 4 and adheres to the FPC 4.

With this structure, the image forming apparatus of this embodiment has the following operational effects. As described above, the spacer 5 formed in a thin plate shape is extremely easily deformed. For example, as shown in FIG. 7A, when the FPC 4 has a corrugation and the spacer 5 is closely attached to such an FPC 4, the end portion of the spacer 5 that is closely adhered to the FPC 4 in accordance with the corrugation. 59 is also transformed. In addition, for example, as shown in FIG.
Even if the thickness of the adhesive layer 60 for bonding the C4 and the spacer 5 is uneven, the end portion 59 of the spacer 5 is deformed according to the unevenness. When such deformation of the spacer 5 in the width direction occurs at the other end portion 58 of the spacer 5 that abuts the toner layer TL on the developing roller 12, the toner particles T constituting the toner layer TL are not uniform. Since the contact pressure is applied, the flying amount of the toner at the toner flying start position J becomes non-uniform in the width direction X, and uneven density of the image occurs.

Therefore, in this embodiment, as shown in FIG. 6, the adhesion portion between the spacer 5 and the FPC 4 is farthest from the one end portion 58 of the spacer 5 which is in contact with the toner layer TL on the developing roller 12. Only the other end 59 is provided.
Therefore, at the one end portion 58 side contacting the toner layer TL, F
The spacer 5 is not deformed due to the waviness of the PC 4 and the uneven thickness of the adhesive layer 60.

Further, in this embodiment, the end portion 59 adhered to the FPC 4 and the end portion 5 contacting with the toner layer TL.
8 and a spacer reinforcing rib 55 is provided between them. This makes it difficult to bend the spacer 5 in the width direction X, and even if the spacer 5 is deformed at the end 59 bonded to the FPC 4, the deformation is opposite to the spacer reinforcing rib 55. Side end portion, that is, the toner layer T
It is prevented from reaching the end 58 which is in contact with L. As described above, in this embodiment, the spacer reinforcing ribs 55 function as the deformation suppressing member of the present invention, whereby the contact pressure applied to the toner T on the developing roller 12 becomes uniform in the width direction X, so that the density is reduced. It is possible to perform stable image formation without unevenness.

As described above, in the image forming apparatus of this embodiment, the spacer 5 is inserted between the toner layer TL on the developing roller 12 and the FPC 4 for controlling the toner flying from the upstream side in the toner conveying direction D. As a result, it is possible to stably form the toner image by keeping the gap GP constant. Then, the spacer 5 is adhered to the FPC 4 at an upstream end 59 that is far from the contact end 58 that comes into contact with the toner layer TL, and the upstream end 59 and the contact end 58 are bonded together. By providing the spacer reinforcing rib 55 as a deformation suppressing member between them, the spacer 5 that can be generated by attachment to the FPC 4
Of the contact side end 58 is prevented.
As a result, the pressure applied to the toner carried on the developing roller 12 becomes uniform, so that the flying amount of the toner at the toner flying start position J becomes uniform in the width direction X, and as a result, this image forming apparatus can reduce the density. It is possible to stably form a toner image having good image quality without unevenness.

The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the spacer reinforcing rib 55 formed in a rod shape having a rectangular cross-sectional shape is provided on the spacer 5 as the “deformation suppressing member” of the present invention, but as the deformation suppressing member of the present invention, In addition to this, various forms can be used as exemplified below.

8 to 10 are views showing various forms of the deformation suppressing member or the deformation suppressing portion in the image forming apparatus according to the present invention. As shown in FIG. 8, in addition to the above, the cross-sectional shape of the spacer reinforcing rib is, for example, a circle (reference numeral 55a shown in FIG. 8A), a triangle (55b shown in FIG. 9B), or another polygonal shape. And the number to be provided is 2 as shown in FIG.
It may be more than one. Further, this deformation suppressing member does not necessarily have to be fixed to the spacer 5, and is formed so as to be able to come into contact with and separate from the spacer 5 so as to come into contact with the spacer 5 in the vicinity of the toner flying start position J or the spacer 5. The deformation may be suppressed by sandwiching.

Further, in the above-mentioned embodiment, the deformation suppressing member for preventing the deformation of the spacer 5 is formed separately from the spacer 5 and is attached to the spacer 5, but as shown in FIG. 9, the shape of the spacer 5 itself. May be devised to have a function of suppressing the deformation. For example, in the spacer 500 shown in FIG.
8 and 509 are thinly formed, a thick portion 505 having a thickness larger than those of both ends is provided in the center thereof. By providing the thick portion 505 in this manner, it is difficult for the spacer 500 to bend in the width direction X, and the FPC 4 is not formed at one end 509 of both ends.
Even if it is adhered to the
It does not extend to Therefore, by using the spacer 500 having such a configuration, the spacer 50 at the contact position with the toner layer TL is similar to the spacer 5 and the spacer reinforcing rib 55 in the above-described embodiment.
It is possible to prevent the deformation of 0 in the width direction. Thus, in this spacer 500, the thick portion 50
5 functions as the deformation suppressing portion of the present invention.

In addition to the shape of the spacer 500, as shown in FIG. 9B, for example, the spacer 500 may be formed to be thick except for the end portion 508 on the contact side with the toner layer TL. Good. In this case, the spacer 50
0 The bending rigidity as a whole is increased, and the abutting end 5
The deformation of No. 08 can be suppressed more effectively, and the spacer 500 having such a high bending rigidity is used as the FP.
By adhering to C4, the effect of correcting the deformation of FPC4 can also be mentioned.

Further, as shown in FIG. 10A or 10B, the spacers 510 and 520 formed in a thin plate shape may be bent along the width direction X thereof. By doing so, the bending strength of the spacers 510, 520 in the width direction X is increased, and one end 519,
It is possible to prevent the deformation of 529 from reaching the opposite ends 518, 528. In this case, the bent parts 515 and 525 function as the deformation suppressing part of the present invention. The form and the number of times of bending are arbitrary and may be other than those shown in FIG.

Further, in the above embodiment, the spacer 5 is provided upstream of the toner flying start position J in the toner transport direction D, but the spacer 5 is provided downstream of the toner flying start position J. You may do it. In this case, the arrangement of the respective parts is such that the respective parts other than the developing roller 12 in FIG. 6 are laterally reversed about the toner flying start position J. In this case, the toner layer TL on the developing roller 12 reaches the toner flying start position J without touching the spacer, but is pressed against the developing roller 12 by contacting the spacer on the downstream side thereof. At this time, if the contact pressure becomes nonuniform, the removal of these toners and the formation of a new toner layer become uneven, and a uniform toner layer cannot be formed. Therefore, by applying the present invention also to the spacer provided on the downstream side and providing the same deformation suppressing member or the deformation suppressing portion as in the above-described embodiment, it is possible to form a stable toner image with good image quality. It will be possible. When the spacer is provided on the downstream side, in order to prevent the toner from being scraped off from the developing roller by the edge of the spacer and being deposited around the toner passage hole, as shown in FIG.
It is preferable to provide a taper at the edge portion of 2.

Further, for example, in the above embodiment, after the toner image is formed on the transfer medium such as the intermediate transfer belt 23,
The present invention is applied to an intermediate transfer type image forming apparatus that transfers the toner image on the transfer medium to the sheet S. However, the charged toner T flying from the developing device 1 is directly landed on the sheet S to form an image. The present invention may be applied to an image forming apparatus to be formed.

Further, in the above embodiment, the semiconductive layer 49.
The present invention is applied to an image forming apparatus in which the FPC 4 is provided with antistatic property, but the application target of the present invention is not limited to this, and an antistatic semiconductive layer is provided. The present invention can be applied to an image forming apparatus which is not provided.

Further, in the above embodiment, the deflection electrode 45 is used.
The flying directions of the charged toner T are three directions P by L and 45R.
Although the present invention is applied to an image forming apparatus that can switch between 1, P2, and P3, the application target of the present invention is not limited to this, and an image in which the flight direction of the charged toner T is fixed is used. The present invention can be applied to a forming apparatus.

In the above embodiment, the spacer 5 is brought into contact with the semiconductive layer 49 so that the spacer 5 is prevented from being charged and the electric field in the vicinity of the toner passage hole 41 is not disturbed. Although it is applied, another bias potential may be applied if necessary.

Furthermore, in the above-described embodiment, the present invention is applied to an image forming apparatus that forms an image with one developing device 1, that is, executes so-called single-color printing. However, in the case of forming a full-color image, for example. In contrast to a so-called tandem type color image forming apparatus in which the same developing devices 1 for four types of toners of yellow, magenta, cyan and black are arranged in a line in the conveyance direction Y of the intermediate transfer belt 23 or the sheet S, However, the present invention can be applied.

[0059]

As described above, according to the present invention, the gap defining means is provided between the toner layer on the toner carrying member and the toner flying control means so that the gap between the toner carrying body and the toner flying control means is increased. In order to suppress the deformation of the thin gap defining means, the gap defining means is provided with a deformation suppressing member or a deformation suppressing portion. Therefore, at the contact position with the toner layer, the gap defining means is kept flat without being deformed, and the pressure exerted by the contact of the gap defining means with each toner particle forming the toner layer, that is, the contact force The contact pressure is substantially uniform within the image forming range in the width direction. Therefore, in this image forming apparatus, the uniformity of the toner layer conveyed to the toner flying start position is maintained, and as a result, a stable toner image with good image quality can be formed.

Further, the deformation suppressing member or the deformation suppressing portion provided in the gap defining means is arranged at a position farther from one end which comes into contact with the toner layer when viewed from the toner flying start position. Therefore, it is possible to form one end of the gap defining means that comes into contact with the toner layer to be extremely thin, and to effectively suppress the deformation thereof. By doing so, the gap can be kept small and uniform, It is possible to form a stable toner image.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a block diagram showing an electrical configuration of the image forming apparatus of FIG.

FIG. 3 is a diagram showing a partially enlarged cross section of a flexible printed circuit board and a flying model of charged toner.

FIG. 4 is a diagram showing control electrodes and deflection electrodes formed on a flexible printed circuit board.

FIG. 5 is a diagram showing spacers and spacer reinforcing ribs in this image forming apparatus.

FIG. 6 is a diagram showing a state in which a spacer is attached to an FPC.

FIG. 7 is a diagram illustrating an operation of a spacer reinforcing rib in this image forming apparatus.

FIG. 8 is a diagram showing various forms of a deformation suppressing member in the image forming apparatus according to the present invention.

FIG. 9 is a diagram showing various forms of a deformation suppressing unit in the image forming apparatus according to the present invention.

FIG. 10 is a diagram showing another form of the deformation suppressing portion in the image forming apparatus according to the present invention.

FIG. 11 is a diagram showing a configuration in which a spacer is provided on the downstream side.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Developing device 3 ... Back electrode 4 ... FPC (toner flying control means) 5,500, 510, 520 ... Spacer (gap defining means) 12 ... Developing roller (toner carrier) 23 ... Intermediate transfer belt (image receiving body) 55 ... Spacer reinforcing rib (deformation suppressing member) 505 ... Thick portion (deformation suppressing portion) 515, 525 ... Bent portion (deformation suppressing portion)

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2C162 AE09 AE25 AE31 AE47 AE56                       AE69 AH03 CA03 CA12 CA13                       CA24                 2H029 DB04

Claims (9)

[Claims] 1. A toner carrier which carries a charged toner and moves the toner in a predetermined moving direction to a toner flying start position, and a toner carrier facing the toner flying start position of the toner carrier. Is arranged between the toner carrier and the back electrode, and is transported between the toner carrier and the back electrode by controlling the toner flight from the toner carrier to the back electrode. A toner flight control means for forming a toner image by landing a toner on an image receiving body, and a toner layer extended on a width direction orthogonal to a moving direction of the toner carrier and carried on the toner carrier. A gap defining unit that is inserted between the toner flying control unit and defines a gap between the toner carrier and the toner flying control unit; The defining means includes a deformation suppressing member for suppressing deformation of the gap defining means in the width direction, on a side opposite to the toner flying start position with respect to one end of the gap defining means that comes into contact with the toner layer. An image forming apparatus characterized by. 2. The image forming apparatus according to claim 1, wherein the gap defining unit is fixed to the toner flying control unit at the other end opposite to the one end in contact with the toner layer. 3. The deformation suppressing member is in contact with the gap defining means at an abutting portion extending in the width direction between the one end and the other end of the gap defining means. The image forming apparatus described. 4. The image forming apparatus according to claim 1, wherein the deformation suppressing member has a bending rigidity in the width direction larger than that of the toner flying control means. 5. A toner carrier that carries a charged toner and moves the toner in a predetermined moving direction to a toner flying start position, and a toner carrier facing the toner flying start position of the toner carrier. Is arranged between the toner carrier and the back electrode, and is transported between the toner carrier and the back electrode by controlling the toner flight from the toner carrier to the back electrode. A toner flight control means for forming a toner image by landing a toner on an image receiving body, and a toner layer extended on a width direction orthogonal to a moving direction of the toner carrier and carried on the toner carrier. A gap defining unit that is inserted between the toner flying control unit and defines a gap between the toner carrier and the toner flying control unit; The defining means is integrally formed with the gap defining means on the side opposite to the toner flying start position with respect to the one end of the gap defining means that comes into contact with the toner layer, and the width direction of the gap defining means. An image forming apparatus, comprising: a deformation suppressing unit that suppresses deformation in the above. 6. The gap defining means is formed in a thin plate shape and is formed integrally with the thin portion including the one end portion, and the gap defining means is provided between the one end portion and the other end portion. A thick portion formed by increasing the thickness of the gap defining means in the direction orthogonal to the moving direction and the width direction from the thin portion, and the thick portion functions as the deformation suppressing portion. Item 5. The image forming apparatus according to item 5. 7. The gap defining means is formed in a thin plate shape having at least one bent portion along a straight line substantially parallel to the width direction, and the bent portion functions as the deformation suppressing portion. 5. The image forming apparatus according to item 5. 8. The image forming apparatus according to claim 1, wherein the gap defining unit is provided upstream of the toner flying start position in the moving direction of the toner carrier. 9. The image forming apparatus according to claim 1, wherein the gap defining unit is provided on the downstream side in the moving direction of the toner carrier with respect to the toner flying start position.