JP2002211027A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus in which the relative position between a back face electrode and a developer passage control substrate can be measured through a simple arrangement. SOLUTION: The imaging apparatus comprises a developer carrier, a developer passage control substrate disposed in the vicinity of the developer carrier while being provided with an array of a plurality of small holes for passing developer and controlling passage of developer through the small holes, a back face electrode disposed oppositely to the developer passage control substrate and generating an electric field for flying the developer between the back face electrode and the developer carrier, an image receiving member interposed between the developer passage control substrate and the back face electrode and forming an image when the developer passed through the small holes adheres to the surface of the image receiving member, a potential detection element for detecting the strength of an electric field generated on the developer passage control substrate by the back face electrode in the form of a potential, and means for recognizing positional relation between the developer passage control substrate and the back face electrode based on the detection results of the potential detection element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image forming apparatus applied to a copying machine, a facsimile, a printer, and the like.

[0002]

2. Description of the Related Art In recent years, in offices, with the improvement of personal computer capabilities and the advancement of network technology,
High-performance printers that can handle large volumes of documents,
Facsimiles and copiers are becoming widespread. On the other hand, color documents are also increasing due to the rapid spread of inkjet printers and the like. However, engines capable of outputting satisfactory black-and-white or color documents including printing speed are under development, and their appearance is expected.

One conventional image forming apparatus uses a direct marking method of forming an image directly on a recording member. For example, an image forming apparatus disclosed in JP-B-44-26333 proposes a developer injection type apparatus which is one of direct marking methods. This is because an image signal is input to an image signal electrode provided in a print head to generate an accelerating electric field, a charged developer passes through a small hole near the image signal electrode, and the developer is applied to a counter electrode. The recording medium is landed on the recording paper to form an image.

[0004] In contrast to the above direct marking system,
It has been proposed that a developer lands on the surface of a transfer belt, an image is formed on the surface of the transfer belt, and the image is transferred to a recording sheet. FIG. 18 is a schematic diagram of an image forming apparatus of a type using the transfer belt as a reference example. The developing unit 1001 of this type of image forming apparatus includes:
Storage containers 1003a to 1003d for storing developers of four colors of yellow, magenta, cyan and black, and a developing roller 1004a for carrying and transporting the developer on the peripheral surface
Developer supply unit 1002a consisting of
1002 to 1002d are continuously provided. Further, the developing roller 10
Prior to 04a to 1004d, a developer passage control substrate (recording head) 1005 in which small holes through which the developer passes is formed.
a to 1005d are installed.

An image receiving unit 1006 is arranged so as to face the developing unit 1001. The image receiving unit 1006 includes a transfer belt 1009 stretched between a pair of rollers 1007 and 1008, and a transfer belt 1009.
9 and back electrodes 1010a to 1010d opposed to the developing rollers 1004a to 1004d with the developer passage control substrates 1005a to 1005d interposed therebetween.

When a color image forming apparatus adopting the above-described printing method is configured as a color image apparatus, a developer passing control board (printing head) is generally called a tandem type for each color.
1005a to 1005d have independent configurations. For this reason, color unevenness, color shift, and the like are likely to occur in the final image of each color.

The causes of color unevenness, color misregistration, etc. are caused by developer passage control substrates (print heads) 1005a to 1005d.
Mounting position accuracy of each developer supply unit 1002a
Each developer supply unit 1002a due to a pitch error of 1002 to 1002d, speed fluctuation of the transfer belt 1009, and temperature rise
To 1002d or a developer passage control substrate (recording head) 10
The position fluctuations of 05a to 1055d are increased. Since such color unevenness, color misregistration, or skew can be a fatal defect in image quality, a configuration / method capable of correcting the defect at low cost has been proposed.

In this method, four colors of the color misregistration measurement pattern are once formed on the transfer belt 1009. Next, the formed measurement pattern is irradiated by an LED or a semiconductor laser or the like, and the reflected light is scanned by a CCD or a photodiode which is a reflection sensor for receiving light. Then, the scanning result is compared with the original measurement pattern, and the amount of deformation of the pattern is measured. Next, the skew, color shift / uneven color amount are calculated from the change amount. Then, correction is performed according to the calculated skew, color shift / color unevenness amount. To make a specific correction, each developer passage control substrate (print head) 1005
A line writing timing for each of a to 105d is operated.

[0009]

However, in the above-mentioned conventional example, in order to calculate the skew, the amount of color misregistration, and the amount of color unevenness, an LED or a semiconductor laser for irradiation and a reflective sensor for receiving light are used to transfer the light onto the transfer belt 1009. It is necessary to recognize the measurement pattern recorded in the. Therefore, the irradiation LED or the semiconductor laser and the reflection type sensor for light reception are connected to the respective developer passage control substrates (recording heads) 1005a to 1005a.
It must be provided separately from the image forming portion downstream of 1005d in the transport direction of the recording paper. Further, at least two sensors are required in the width direction of the transfer belt 1009 to detect the skew. In the above configuration, the reliability of the correction value cannot be maintained unless the arrangement / geometric accuracy of the plurality of sensors is also maintained. For this reason, the man-hour for adjusting the sensor arrangement is increased. Therefore, this conventional configuration tends to increase the number of parts and increase the cost.

The flight time of the toner is determined by the back electrode 10
10a to 1010d and a developer passage control substrate 1005a to
It corresponds to the distance to 1005d. Therefore, the back electrode 10
10a to 1010d and a developer passage control substrate 1005a to
A change in the distance from 1005d changes the flight time of the toner. The flying time of the toner has a large effect on image quality and recording speed. Therefore, the back electrodes 1010a to 1010
The precision of the distance between 0d and the developer passage control boards 1005a to 1005d is strict, and it is necessary to manage ± 10 μm.

At present, an engineer applies paper or a thin plastic film to the back electrodes 1010a to 1010d.
And between the developer passage control boards 1005a to 1005d, and the distance is determined based on the feel of the hand felt at that time.
Then, based on this determination, the adjustment mechanism is used to control the back electrodes 1010a to 1010d and the developer passage control board 1005.
The positional relationship with a to 105d is adjusted.

However, such back electrodes 1010a to 1010d and the developer passage control substrate 1
The measurement of the distance from 005a to 1055d requires a skilled technique. Therefore, there is a problem that the distance between the back electrodes 1010a to 1010d and the developer passage control substrates 1005a to 1005d can be measured only by a specific person.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an image forming apparatus capable of measuring a relative position between a back electrode and a developer passage control substrate with a simple configuration.

[0014]

In order to solve this problem, an image forming apparatus according to the present invention comprises a developer carrying member for carrying and transporting a developer, and a developer arranged near the developer carrying member. A developer passage control substrate that forms a row of small holes that pass therethrough and controls the passage of developer through the small holes, and an electric field that is arranged opposite to the developer passage control substrate and causes the developer to fly And a receiving member that forms an image by adhering to the surface a developer that is disposed between the developer passage control substrate and the back electrode and that passes through the small hole. , A potential detection element that detects the strength of the electric field generated by the back electrode on the developer passage control board as a potential, and recognizes a positional relationship between the developer passage control board and the back electrode based on a detection result of the potential detection element. And position recognizing means.

Thus, the positional relationship between the developer passage control substrate and the back electrode, that is, the positional relationship between the row of small holes and the back electrode can be determined from the potential detected by each potential detecting element. Since it is relatively easy to increase the accuracy of the back electrode, skew and color misregistration can be suppressed if the back electrode can be adjusted with reference to the back electrode. The skew / color misregistration correction amount of the image forming apparatus can be determined from the positional relationship described above.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An image forming apparatus according to a first aspect of the present invention includes: a developer carrying member for carrying and transporting a developer;
A developer passage control substrate that is arranged near the developer carrier and that forms a small hole array including a plurality of small holes through which the developer passes and controls the passage of the developer through the small holes; A back electrode that is arranged to face the developer passage control substrate and generates an electric field for causing the developer to fly between the developer carrier, and a back electrode that is arranged between the developer passage control substrate and the back electrode. An image receiving member that forms an image by the developer that has passed through the small hole adhering to the surface; and a potential detection that detects, as a potential, the intensity of the electric field generated by the back electrode on the developer passage control substrate. And a position recognizing means for recognizing a positional relationship between the developer passage control substrate and the back electrode based on a detection result of the potential detecting element.

With this configuration, the positional relationship between the developer passage control substrate and the back electrode, that is, the positional relationship between the row of small holes and the back electrode can be determined from the potential detected by each potential detecting element. Then, the skew / color misregistration correction amount of the image forming apparatus can be determined from this positional relationship.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the potential detected by the potential detection element and the developer passage control substrate corresponding to the potential and the back electrode A distance storage unit that stores a plurality of pairs of distances, and by referring to the distance storage unit, recognizes a distance between the developer passage control board and the back electrode corresponding to the potential detected by the potential detection element. It adopts the configuration of doing.

With this configuration, the potential from the back electrode corresponding to the potential detected by the potential detection element to the developer passage control substrate is detected by detecting the potential with the potential detection element and comparing the detected potential with the initial value stored in the distance storage means. Can understand.

According to a third aspect of the present invention, in the image forming apparatus according to the first aspect or the second aspect, the plurality of potential detecting elements are arranged symmetrically with respect to the row of small holes. Take.

According to this configuration, the positional relationship between the back electrode and the row of small holes can be grasped more accurately by detecting the potential with a plurality of potential detecting elements arranged symmetrically with respect to the row of small holes.

According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, the inclination of the row of small holes with respect to the back electrode is compared by comparing the potentials detected by the plurality of potential detecting elements. Is adopted.

With this configuration, the skew inclination of the row of small holes with respect to the back electrode can be detected by comparing the potentials detected by the plurality of potential detecting elements symmetrically arranged with respect to the row of small holes.

According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the potential detecting element is a coil sensor, and the back electrode is configured to generate and eliminate an electric field. Is repeated to generate the potential in the coil sensor.

With this configuration, the configuration of the potential detecting element is simplified, and the cost can be reduced.

According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, the potential detecting element is formed integrally with the developer passage control substrate. Take the configuration.

With this configuration, the potential detection element can be formed integrally with the developer passage control substrate, so that the cost is advantageous.
In addition, by integrally forming the potential detection element on the developer passage control substrate, the positional relationship between the potential detection element and the row of small holes can be controlled with high accuracy. Thereby, the skew amount of the small hole array can be easily obtained, and the distance between the back electrode and the developer passage control substrate can be stably measured.

According to a seventh aspect of the present invention, there is provided an image forming apparatus comprising: a developer carrying member for carrying and transporting a developer; and a plurality of small holes arranged near the developer carrying member and through which the developer passes. And a developing unit having a developer passage control substrate for controlling passage of the developer through the small holes, and a developing unit disposed opposite the developer passage control substrate of the developing unit. A back electrode that generates an electric field for causing the developer to fly on the image receiving member that forms an image by the agent adhering to the surface of the developer carrier, according to the number of colors of the developer. An image forming apparatus having a plurality of potential detection elements for detecting, as a potential, the intensity of the electric field generated by the back electrode disposed on the developer passage control substrate of each of the developing units; and Multiple potentials Leaving a configuration provided with the, position recognizing means for recognizing the positional relationship between the developer passing controller board said back electrode of said respective developing units by comparing the potential of detecting elements.

According to this configuration, the potential detection element is provided on each of the developer passage control boards of the developing units provided with the developer carriers accommodating the developers of a plurality of colors. As a result, the positional relationship between the row of small holes corresponding to a plurality of colors and the back electrode corresponding thereto can be determined, and the correction amount of the skew and color shift can be obtained. Thereby, the printing position for all of the plurality of colors can be adjusted to each back electrode, so that color misregistration can be suppressed.

Embodiment 1 Hereinafter, an image forming apparatus according to Embodiment 1 of the present invention will be described with reference to the accompanying drawings. First, the configuration of the image forming apparatus according to the first embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view illustrating a schematic configuration of the image forming apparatus according to the first embodiment of the present invention. In FIG. 1, the right side is the front side of the image forming apparatus, and the left side is the rear side.

As shown in FIG. 1, a recording paper cassette 10 is disposed in the vicinity of the bottom of the main body 2 of the image forming apparatus 1 and on the front side. The recording paper cassette 10 has a detachable configuration. Inside the recording paper cassette 10, a recording paper mounting plate 101 is provided. The recording paper 102 is placed in a stacked state so that a part of the recording paper 102 is placed on the recording paper
0 is stored. A lift unit 103 is provided at an end of the recording paper placing plate 101.

The lift unit 103 lifts the rear end of the recording paper mounting plate 101 upward by a spring (not shown). As a result, the uppermost recording paper 102 on the recording paper mounting plate 101 is regulated by the triangular claws (not shown).
At this time, the actuator 1 above the recording paper 102
04 detects the presence or absence of the recording paper 102. In addition,
If the recording paper 102 is not stored in the recording paper cassette 10, the operator of the image forming apparatus 1 is notified of the fact.

A feed roller 105 having a semicircular cross section is provided slightly behind the actuator 104.
The paper feed roller 105 is rotated clockwise by a drive unit (not shown), and feeds the uppermost recording paper 102 into the apparatus. As a result, the recording paper 102 is
Even if the number is reduced to 0, the last sheet is fed.

A recording paper guide 106 is provided slightly behind the paper supply roller 105 in the paper supply direction. A pair of conveying rollers 10 is provided near the front end of the recording paper guide 106.
7 are provided. The transport roller 107 transports the recording paper 102 fed by the feed roller 105 in the same direction. An actuator 108 is arranged near the center of the recording paper guide 106. The actuator 108
The position of the leading end of the recording paper 102 conveyed through the recording paper guide 106 is detected. Further, a pair of registration rollers 109 is provided near the rear end of the recording paper guide 106. The registration roller 109 adjusts the conveyance of the recording paper 102 so that the leading end position of the recording paper 102 detected by the actuator 108 and the leading end of the image formed on the transfer belt to be described later coincide with the leading end of the recording paper 102.

On the other hand, an image forming unit 20 is disposed above these paper feed mechanisms. Image forming unit 20
Is a developing unit 210 for forming a plurality of color images.
And an image receiving unit 220 on which a single-color image formed by the developing unit 210 is superimposed.

The developing unit 210 has a flexible printed circuit board in which developer supply units (hereinafter referred to as developing units) 211a to 211d containing toners as developers of four colors of yellow, magenta, cyan and black are inserted. (Hereinafter, "FPC" (Flexible
Four head units 212a to 212d (referred to as Printed Circuits) are provided above and below.
The FPC head units 212a to 212d are configured to be detachable from an FPC folder unit (not shown) provided in the developing unit 210. The details of the FPC head units 212a to 212d will be described later.

Each of the developing units 211a to 211d
It is configured to be detachable from the PC head units 212a to 212d. It is removed when toner inside the developing units 211a to 211d is replenished or the like. Further, the developing device 211a
Grips 213a to 213d for facilitating removal from the development unit 210
Is provided. Further, developing units 211a to 211d
A developing roller 21 carrying toner is
4a to 214d are provided. Such a developing device 2
11a to 211d are FPC head units 212a to 2
Pressing portions 215a to 215 formed of springs or the like from the front side so as to be fixed at a predetermined position when mounted on 12d.
d is pressing.

The image receiving unit 220 includes an endless transfer belt 221 wound around three belt rollers 222a to 222c.

The belt roller 222a is arranged above the uppermost FPC head unit 212a, and the belt roller 222c is arranged below the lowermost FPC head unit 212d. The belt roller 222b has a height corresponding to a substantially intermediate position between the FPC head units 212c and 212d, and is disposed at a position in contact with the inside of the transfer belt 221 disposed on the rear side. This is transfer belt 2
This is for giving a tension to 21. Belt roller 222c
Supports the transfer belt 221 and is connected to a drive motor (not shown), and functions as a drive roller for the transfer belt 221.

Back electrodes 223a to 223d are provided inside the transfer belt 221 arranged on the front side and at positions facing the developing rollers 214a to 214d, respectively. In other words, the developing rollers 214a to 214d and the back electrodes 223a to 223 via the transfer belt 221.
3d is facing. Also, the back electrodes 223a to 223
Has a circular cross section, that is, a roller shape, so as to smoothly contact the transfer belt 221.

A box-shaped waste toner unit 230 is provided on the rear side of the belt roller 222a. The waste toner unit 230 is provided in a detachable configuration. Inside the waste toner unit 230, the waste toner unit 23
The shaft 231 is fixedly provided on the housing 0. A blade 232 is attached to the front side of the shaft 231.

The tip of the blade 232 protrudes from the housing of the waste toner unit 230. The tip of the blade 232 is just the belt roller 222.
a and comes in contact with the surface of the transfer belt 221 at a position on the rear side. As a result, the toner remaining on the transfer belt 221 without being transferred to the recording paper 102 is scraped off by the blade 232. The scraped toner is used as the waste toner unit 23.
It is stored in 0.

As shown in FIG. 1, the lower belt roller 222c around which the transfer belt 221 is wound is disposed slightly above the registration roller 109 in the conveying direction of the recording paper 102.

The transfer unit 30 is disposed below the belt roller 222c and on the rear side of the above-described paper feeding mechanism. The transfer unit 30 is provided in a detachable configuration on the rear surface side, and improves the maintainability when a paper jam occurs in the image forming apparatus 1.

On the front side of the transfer unit 30, a transfer roller 301 is provided above and at a position facing the belt roller 222c. The transfer roller 301 transfers images of a plurality of colors formed on the transfer belt 221 to the recording paper 102. Specifically, the toner constituting the image on the transfer belt 221 is electrically drawn to the transfer roller 301 side, and the image is transferred to the recording paper 102.

On the front side of the transfer roller 301, a recording paper guide 302 formed integrally with the housing of the transfer unit 30 is provided. The recording paper guide 302 transports the recording paper 102 conveyed from the registration roller 109 to the belt roller 2.
It is led to the contact surface between the transfer roller 301 and the transfer roller 301.

The connecting members 303a and 303b are connected to the transfer roller 301. A solenoid 304 is connected to one end on the rear surface side of the connecting portion 303b. Further, one end of the spring 305 is hooked on one end on the front side of the connecting member 303b. The other end of the spring 305 is the transfer unit 3
0 is hooked on the housing. Normally, this spring 30
5 pulls the connecting member 303b to the front side,
The transfer roller 301 is moved rearward with the shaft 306 as a fulcrum, and is in a state separated from the belt roller 222c. At a predetermined timing, the solenoid 304 causes the transfer roller 301 to contact the belt roller 222c. That is, the solenoid 304 transfers the transfer belt 2 to the recording paper 102.
The transfer roller 30 is used to transfer the image formed on the transfer roller 21.
1 is brought into contact with the belt roller 222c.

A blade 307 is provided on the rear side of the connecting member 303a. The blade 307 is a member for scraping toner adhered to the transfer roller 301. The toner on the recording paper 102 is transferred to a belt roller 222c.
Since the transfer is performed on the transfer roller 301 side, it is generally not considered that the toner adheres to the transfer roller 301. However, assuming that toner adheres to the transfer roller 301 due to malfunction due to paper jam or the like, such a blade 307 is used.
Is provided.

A recording paper guide 308 is provided slightly above the transfer roller 301 and on the rear side. The recording paper guide 308 is provided in a swingable configuration. When the transfer unit 30 is mounted on the image forming apparatus 1, the recording sheet guide 308 rises as shown in FIG. 1 and moves to a position where the recording sheet 102 is guided, while the transfer unit 30 is moved from the image forming apparatus 1. When the image forming apparatus 1 is removed, the image forming apparatus 1 is stored in the storage unit 309, thereby improving maintainability of the image forming apparatus 1. Accordingly, when the transfer unit 30 is removed for maintenance or the like inside the apparatus, the maintenance property inside the apparatus is improved, and when the maintenance or the like is not required, the conveyance of the recording paper 102 is securely performed. Can be done.

As shown in FIG. 1, the fixing unit 40 is arranged in the conveying direction of the recording paper 102 when the recording paper guide 308 is raised. The fixing unit 40 also
Like the transfer unit 30, the transfer unit 30 is provided in a detachable configuration on the rear surface side, thereby improving the maintainability when a paper jam occurs in the image forming apparatus 1.

Since the fixing unit 40 is disposed above the transfer unit 30, the transfer unit 3 in the apparatus is
A conveyance path for the recording paper 102 from 0 is formed upward. For this reason, inside the apparatus, the recording paper 10
The space for the second conveyance path can be reduced. Thereby, the size of the image forming apparatus 1 can be reduced.

The fixing unit 40 is provided with the conveyed recording paper 1
A receiving port 400 for facilitating receiving of the fixing unit 02 is provided below the housing of the fixing unit 40. Entrance 400
The recording paper 102 is provided in a shape that gradually narrows as the recording paper 102 is transported, and also serves as a guide for the recording paper 102. The fixing roller 402 and the heater roller 403 are provided inside the receiving port 400.

Recording paper 1 received from receiving port 400
02 enters the contact surface between the fixing roller 402 and the heater roller 403. The heater roller 403 applies heat to the recording surface of the recording paper 102, and the fixing roller 402 presses the recording paper 102 between the recording paper 102 and the heater roller 403, so that an image is fixed on the recording paper 102.

The oil roller 404 and the cleaning roller 405 are provided so as to contact the peripheral surface of the heater roller 403. The oil roller 404 supplies a predetermined amount of oil to the heater roller 403, thereby enhancing the toner releasability of the heater roller 403.
The cleaning roller 405 is made of, for example, a solid aluminum material. Also, the cleaning roller 405
The temperature of the heater roller 403 is lower than that of the heater roller 403, so that unnecessary toner adhering to the heater roller 403, in other words, toner not fixed on the recording paper 102 is offset toward the cleaning roller 405.
(Fixed).

The recording paper 102 discharged from the contact surface between the fixing roller 402 and the heater roller 403 passes through a transport path 406 formed by the housing of the fixing unit 40. A pair of discharge rollers 407 is provided at the end of the transport path 406. The discharge roller 407 discharges the recording paper 102 transported on the transport path 406 to the outside of the fixing unit 40.

A recording paper guide 408 is provided in the conveying direction of the recording paper 102 discharged by the discharge roller 407. The recording paper guide 408 regulates conveyance of the recording paper 102 discharged from the discharge roller 407. This allows
The paper discharge tray 40 arranged below the recording paper guide 408
The recording paper 102 on which an image has been formed is discharged.

Here, the developing unit 211 and the FPC head unit 2 which are members constituting the developing unit 210
The configuration around 12 will be described in detail with reference to FIG.
FIG. 2 is a partially enlarged view showing the configuration around the developing device and the FPC head unit. In FIG. 2, the pressing portion 21
5 and the developing device 2
11 shows a state mounted in a predetermined position,
The grip 213 of the developing device 211 is omitted.

As shown in FIG. 2, on the transfer belt 221 side of the FPC head unit 212, a developer passage control means for controlling the supply of toner from the developing device 211, that is, an FPC 251 as a recording head is attached. Specifically, one end of the FPC 251 is
The PC head unit 212 is fixed to the lower frame 602. The other end of the FPC 251 is bent to the front side by the stay 253 at the tip of the upper frame 601, and the tension spring 2 is inserted into a spring mounting hole 254 formed near the tip of the other end.
One end of 55 is attached. Further, the other end of the tension spring 255 is attached to a spring hook 256 provided on the upper frame 601. The tension spring 255 pulls the FPC 251 forward. FPC25
Since the stopper 257 is erected at the point where the FPC 251 is pulled, the FPC 251 abuts on the stopper 257, thereby restricting the FPC 251 from moving further. In this way, the FPC 251 is
And the lower frame 602. In addition,
The FPC 251 is made of a sheet-shaped and flexible insulating material.

A spacer 258 is fixed to a surface of the FPC 251 on the side of the developing device 211 (hereinafter, referred to as a “back surface of the FPC 251”) slightly above the axis of the developing roller 214. The spacer 258 is in contact with the developing roller 214 to maintain a constant distance between the FPC 251 and the developing roller 214. The transfer belt 221 is located at a position corresponding to the axis of the developing roller 214 of the FPC 251.
A large number of small holes 259 are formed at a fine pitch along the width direction of.

Here, the small hole 2 drilled in the FPC 251
The structure around 59 will be described with reference to FIG. FIG.
FIG. 2 is an enlarged view of a back surface of the FPC and a surface of the FPC on a transfer belt side (hereinafter, referred to as “a front surface of the FPC”) according to the first exemplary embodiment;

As shown in FIG. 3, the back surface 2 of the FPC 251
A plurality of small hole rows 260 are formed in the small hole 63 by the small holes 259 that are formed. Also, the back surface 2 of the FPC 251
The ring 63 has a ring-shaped image signal electrode (control electrode) 261 formed so as to surround each small hole 259. On the other hand, an aperture electrode 262 is formed on the surface of the FPC 251.

Each image signal electrode 261 is also connected to the FPC 2
51 are connected independently to an image signal output unit serving as an image signal voltage switching means through a lead wire 300 wired on the back surface. Normally, a voltage of 400 V or less is applied to the image signal electrode 261. In the present embodiment, a voltage of 300 V is applied for dot formation, and a voltage of -100 V for non-dot formation.

As shown in FIG. 2, a vibration is applied to the lower side of the small hole 259 formed in this way and on the back surface of the FPC 251 to remove the toner adhered inside or around the small hole 259. A mechanism is provided. This vibration mechanism
A metal vibration plate 264 fixed to the back surface of the FPC 251 along the small hole row 260 and an ultrasonic vibration generator 265 fixedly supported on the outer wall of the developing unit 210 and generating ultrasonic vibration. . The principle of operation will be omitted because it departs from the present invention.

On the other hand, the developing device 211 has a developing roller 21
4, a toner supply roller 266 is provided.
The toner supply roller 266 stirs the toner stored in the developing device 211 to frictionally charge the toner and supplies the toner to the developing roller 214. Further, a toner regulating blade 267 is provided above the developing roller 214. The toner regulating blade 267 regulates the toner layer carried on the developing roller 214.

Further, a regulating collar 268 which comes into contact with the back electrode 223 on the outside of both ends in the axial direction of the developing roller 214 to keep the distance between the developing roller 214 and the back electrode 223 constant.
Is attached. The distance between the back electrode 223 and the developing roller 214 by the regulating collar 268 is, for example, 1
It is maintained at 50 to 1000 μm, and in this embodiment, it is 350 μm.
It is configured to be set to μm. A driving gear (not shown) for transmitting a rotational driving force to the developing roller 214
And rotates the developing roller 214 counterclockwise.

Developing roller 214, toner supply roller 26
6. The toner regulating blade 267 may electrically apply a ground, DC or AC voltage. Further, the toner regulating blade 267 may be electrically floated.

The back electrode 223 functions as a counter electrode and forms an electric field with the developing roller 214.
A conductive filler dispersed in a metal plate or resin is used. Although a DC voltage of about 500 to 2000 V is applied to the back electrode 223, a voltage of 1000 V is applied in the present embodiment.

When a voltage of 1000 V is applied to the back electrode 223, the back electrode 223 and the developing roller 214
An electric field is generated between the two, and the toner carried on the developing roller 214 is attracted to the back electrode 223. In the image forming apparatus 1, the voltage applied to the image signal electrode 261 provided on the FPC 251 is changed. The adjustment controls the toner passing through the small holes 259.
As a result, a desired recorded image is formed.

The image forming apparatus 1 is an apparatus for forming a color image, and it is necessary to match four color images in color printing. Therefore, in the first embodiment, the positional relationship between the back electrode 223 and the small hole row 260, specifically, the inclination of the small hole row 260 with respect to the center line of the back electrode 223 is measured. Although such a measurement of the positional relationship has been conventionally performed, the first embodiment is different from the conventional one, and the back electrode 223a is controlled by the apparatus itself without intervention of a user operation.
It is characterized in that the positional relationship between .about.223d and the small hole 259 is measured.

Specifically, the image forming apparatus 1 according to the first embodiment focuses on the fact that the electric field generated by the back electrodes 223a to 223d changes according to the distance from the back electrodes 223a to 223d. A potential detecting element (coil sensor) for detecting the strength of the electric field as a potential is provided on an FPC (developer passage control board) 251 having a small hole 259 through which the developer passes. Then, by analyzing the detection result of this potential detecting element, the row of small holes 260 is analyzed.
In this case, the positional relationship between the image data and the back electrode 223 is recognized.

Hereinafter, the image forming apparatus 1 measures the positional relationship between the back electrode 223 and the small hole array 260 to obtain the small hole array 260.
A method of measuring the inclination skew of the skew and correcting the skew will be described.

First, a coil sensor of the image forming apparatus 1 according to the first embodiment will be described with reference to FIG. FIG.
FIG. 4 is a diagram for explaining a positional relationship between a row of small holes and a coil sensor according to the first embodiment.

As can be seen from FIG. 4, a small hole array 260 in which a plurality of small holes 259 are horizontally arranged in one line is formed on the front side surface of the FPC 251. In the figure, for convenience,
Although the small hole row 260 is shown by a line, a plurality of small holes 259 are actually formed at equal intervals on a straight line.

Further, on the side front surface of the FPC 251 and near the left end of the row of small holes 260, coil sensors 401a and 40, which are potential detecting elements, are sandwiched by the small holes 259a at the left end.
1b is provided. Further, on the side front surface of the FPC 251 and near the right end of the small hole row 260, a small hole 25 at the left end is provided.
Coil sensor 40 as a potential detection element so as to sandwich 9b
1c and 401d are provided.

The coil sensor 401a and the coil sensor 40
1b is equidistant from the small hole 259a, that is, the small hole 2
It is arranged in a position symmetrical with respect to 59a. Also,
The coil sensor 401c and the coil sensor 401d are arranged at an equal distance to the small hole 259b, that is, at a position symmetrical with respect to the small hole 259b. Further, the coil sensor 401a, the coil sensor 401c, and the coil sensor 401
b, the coil sensor 401d, and the small hole 259c positioned at the center of the small hole row 260,
It is arranged at a position symmetrical with respect to c. The coil sensors 401a and 401d, the coil sensors 401b and 401c, and the small holes 259c are arranged at point-symmetric positions.

Further, the coil sensors 401a to 401d
Is a coil pattern that generates a potential by electrostatic induction by a change in an electric field generated by the back electrode 223. That is, since the coil sensors 401a to 401d are formed integrally with the FPC 251 at the stage of manufacturing the FPC 251, the positional relationship with respect to the small hole row 260 is controlled with high precision.

Next, by measuring the positional relationship between the back electrode 223 and the small hole array 260, the back electrode 223 of the small hole array 260 is measured.
The hardware configuration for measuring the inclination (skew) with respect to the center line and correcting the skew will be described with reference to FIG. FIG. 5 is a hardware block diagram of the image forming apparatus according to the first embodiment.

The image forming apparatus 1 has a main controller CP
U501 is provided. The CPU 501 operates according to a program stored in the storage unit. Further, the image forming apparatus 1 has a ROM 502 and a RAM as storage means.
503 are provided. The ROM 502 is a nonvolatile read-only storage unit, and stores programs and various initial settings. The RAM 503 is a volatile rewritable storage unit, and operates as a work memory of the CPU 501.

The image forming apparatus 1 has a back electrode 22
A back electrode control unit 504 for performing the voltage control of No. 3 is provided. The back electrode control unit 504 turns on and off the voltage of the back electrode 223 according to the image forming signal sent from the CPU 501. Accordingly, the back electrode 223
Generates or disappears an electric field. The back electrode control unit 504 also turns on and off the voltages of the back electrodes 223a to 223d when measuring the skew of the small hole array 260.
F.

The image forming apparatus 1 has a back electrode 22
3, the coil sensors 401a to 401
a potential detecting unit 50 for detecting the potential of the dielectric electromotive force generated in the d.
5 are provided. The potential detecting unit 505 detects each potential of the coil sensors 401a to 401d.

The image forming apparatus 1 includes a potential detecting section 5
05 based on the potentials of the coil sensors 401a to 401d detected by the rear surface electrodes 223a to 223 of the FPC 251.
A position recognition unit 506 for detecting a position with respect to d is provided. The position recognition unit 506 includes:
The skew of the small hole row 260 is detected from the potential difference of 401d.

The image forming apparatus 1 has a position recognition unit 5.
A correction value measuring unit 507 is provided for measuring a skew correction value according to the skew amount of the small hole array 260 recognized by 06. Further, the image forming apparatus 1 includes a correction value measuring unit 5.
A skew correction unit 508 that performs skew correction based on the correction value measured by the counter 07 is provided.

The skew correction unit 508 is provided, for example, in FIG.
As shown in (a) and (b), the row of small holes 260 is
23, in other words, the back electrode 223
FPC25 when inclined with respect to the center line of
The write start timing from 1 is divided into a plurality of parts in the main scanning direction, and a delay in the write start timing is provided for each of the divided areas, so that apparent linearity is obtained. For example, FIG.
As shown in (b), when the skew in which the difference in the main scanning direction between the small hole 259a located at the left end of the small hole row 260 and the small hole 259b located at the right end is δ is divided into four and the skew is corrected. The skew of the printed straight line is the difference δ / 4.

Here, the number by which the skew correction unit 508 divides the write start timing, that is, the skew correction value is
It is determined according to the difference δ. Specifically, the greater the difference δ, the greater the number of divisions. Since such a skew correction method has been conventionally performed, a detailed description thereof will be omitted. 6 (a) and 6 (b)
FIG. 3 is a diagram for explaining skew of a row of small holes according to the first exemplary embodiment;

Next, the image forming apparatus 1 according to the first embodiment measures the positional relationship between the back electrode 223 and the small hole array 260 to determine the amount of tilt skew and the difference between the center of the back electrode 223 and the small hole array 260. An operation of measuring and correcting a correction value such as a deviation of an absolute position (distance), a skew, and a deviation direction of the absolute position will be described with reference to FIG. FIG. 7 is a flowchart of the correction value measurement of the image forming apparatus according to the first embodiment. In FIG. 7, a description will be given of a form in which the skew amount is used as a correction value. The method of correcting the deviation of the absolute position (distance) between the center of the back electrode 223 and the small hole row 260 is adjusted by shifting the printing timing according to the measured absolute position.

When the image forming apparatus 1 starts the correction value measurement (ST701), first, the back electrode control section 504 turns ON / OFF the voltage applied to the back electrode 223 (ST70).
2). As a result, the generation and disappearance of the electric field centering on the back electrode 223 occurs. As a result, voltages (potentials) corresponding to the densities of the lines of electric force passing through the coil sensors 401a to 401d serving as the potential detecting elements are generated in the coil sensors 401a to 401d serving as the potential detecting elements (ST703). Specifically, as shown in FIG.
When the N-OFF operation is performed, a voltage is applied to the back electrode 223 as shown in FIG. Then, as shown in FIGS. 8C and 8D, the back electrode 223 is formed.
Sensors 401a to 401 of lines of electric force generated from
The voltage (potential) according to the density that passes through d is the coil sensor 4
01a to 401d. FIG. 8 is a diagram illustrating a relationship between the ON-OFF operation of the back electrode and the voltage generated in the coil sensor according to the first embodiment.

Here, the coil sensors 401a to 401d
Will be described. As shown in FIG. 9, the potential takes a form inversely proportional to the square of the distance centering on the back electrode 223. When this is expressed by the lines of electric force, as shown in FIG. 10, the lines of electric force exist close to the back electrode 223 or the developing roller 214, and become sparser as the distance increases. That is, the outputs of the coil sensors 401a to 401d are values having the distance to the back electrode 223 as a variable.

For example, as shown in FIG. 10, when the back electrode 223 is perpendicular to the row of small holes 260, that is, when the FPC 251 is accurately arranged with respect to the back electrode 223, the electrode passes through the coil sensors 401a and 401c. The number of lines of electric force is the same as the number of lines of electric force passing through the coil sensors 401b and 401d. In this case, the coil sensor 40
1a and 401c and the coil sensor 401
The potentials detected by b and 401d become the same.

Also, as shown in FIG. 11, when the back electrode 223 is displaced from the small hole row 260 toward the coil sensors 401b and 401d, that is, the FPC 251 is
If they are not arranged correctly with respect to 3, the number of lines of electric force passing through the coil sensors 401a and 401c and the number of lines of electric force passing through the coil sensors 401b and 401d are different. In this case, the coil sensors 401a, 401
The potential detected by c differs from the potential detected by coil sensors 401b and 401d. FIGS. 9 to 11 are diagrams for explaining the electric field between the FPC head unit and the back electrode according to the first embodiment.

As described above, in the image forming apparatus 1, in the potential detecting section 505, the potentials detected by the coil sensors 401 a and 401 c symmetrically arranged in the small hole row 260 and the potentials detected by the coil sensors 401 b and 401 d are determined. Are compared (ST704). Then, the position recognition unit 506 recognizes the position of the small hole array 260 with respect to the back electrode 223 based on the comparison result of the potential detection unit 505, and recognizes the skew amount.

Next, the image forming apparatus 1 includes the coil sensor 4
It is determined whether or not the difference between the output values of the coil sensors 01a and 401c and the coil sensors 401b and 401d is within an allowable value (ST70).
5). In ST705, when image forming apparatus 1 determines that the output value difference is within the allowable value, it determines that skew correction is not necessary, determines that there is no skew correction amount (ST706), and waits for the start of a printing operation. That is, the process enters the standby mode (ST707).

On the other hand, in ST705, when image forming apparatus 1 determines that the output value difference is equal to or larger than the allowable value, it determines that skew correction is necessary, and correction value measuring section 507 detects coil sensors 401a and 401c. The number of main scanning divisions (skew correction amount) is calculated from the relationship between the detected potential, the potentials detected by the coil sensors 401b and 401d, and the distance between the back electrode 223 and the FPC 251 (ST708). Then, the image forming apparatus 1 calculates the calculated skew correction amount as RA
Write to M503 (ST709), and enter standby mode (ST710). Then, when a print command is received, image forming apparatus 1 outputs the print data by dividing it in the main scan in accordance with the number of divisions calculated in ST708. As a result, an image whose skew has been corrected can be output.

As described above, according to the image forming apparatus 1 of the first embodiment, the coil sensors 401a,
The skew amount can be calculated by comparing the output of the coil sensor 401b with the output of the coil sensor 401b. Therefore, in order to adjust the skew, each color head (here, each color FP) is not temporarily printed on the transfer body as in the conventional image forming apparatus.
The inclination amount (skew amount) of C251) with respect to the back electrode 223 can be automatically obtained. As a result, the color adjustment, especially the skew, can be extremely easily adjusted.

In the first embodiment, each of the FPC head units 212a to 212d into which the developer supply units 211a to 211d containing the toners of the four colors of yellow, magenta, cyan and black are inserted. Since the FPC 251 is provided with the coil sensors 401a to 401d, the skew of the small hole array 260 corresponding to all four colors of yellow, magenta, cyan and black can be measured. This makes it possible to match the printing positions for all four colors, thereby preventing the occurrence of color misregistration. Further, the correction of the color shift between the colors is adjusted by shifting the printing timing of another color with reference to a certain color.

Further, the first embodiment uses the coil sensors 401a to 401d which are coil patterns formed at the stage of manufacturing the FPC 251 as the potential detecting element, thereby simplifying the configuration of the potential detecting element and reducing the cost. Not only can be suppressed, but also the positional relationship between the potential detecting element and the small hole array 260 can be controlled with high precision. This allows
The skew of the small hole row 260 can be reliably calculated.

The first embodiment focuses on the fact that it is easier to determine the parallelism and positional relationship of the back electrodes than to achieve the placement accuracy of the FPC 251.
The skew is calculated based on the back electrodes 223a to 223d which can relatively easily obtain the accuracy, so that the accuracy of parts can be improved, and the FPC 251 and the transfer belt 2
21 can be stabilized. Thereby, the small hole row 26
The skew of 0 can be calculated reliably. In addition, the small hole row 26
Since it is not necessary to newly add a component serving as a reference for calculating the skew of 0, the size of the apparatus can be reduced.

In the first embodiment, the coil sensor 4
01a, 401b and coil sensors 401c, 40
1d are arranged symmetrically with the small hole row 260 interposed therebetween, and the coil sensors 401a, 401b, and the coil sensors 401c,
The skew was measured by comparing the output values of 401d, but as shown in FIG.
201f may be arranged. FIG. 12 is a diagram illustrating another example of the positional relationship between the FPC and the coil sensor according to the first embodiment.

The embodiment shown in FIG. 12 has the small hole array 26 in addition to the coil sensors 401a to 401d according to the first embodiment.
Coil sensors 1201c and 1201d are provided symmetrically with respect to a small hole 259c located at the center of 0. Thus, the coil sensors 1201c, 1201d
The skew can be measured more accurately by adding. It should be noted that a mode in which a coil sensor is further added to the mode shown in FIG. 12 may be used.

Further, as shown in FIG.
The coil sensors 1301a to 1301d may be arranged on the front, rear, left and right sides of the small hole 259c located at the center of. FIG. 13 is a diagram illustrating another example of the positional relationship between the FPC and the coil sensor according to the first embodiment.

In the case of the embodiment shown in FIG. 13, the output values of the coil sensors 1301a and 1301c and the coil sensor
1b and 1301d, the small hole array 2
The inclination of the back electrode 223 with respect to the center line can be measured.

In the first embodiment, the back electrode 223 having a roller shape is used as the electric field generating means.
As shown in FIG. 4, the back electrode 1401 may be used for the electric field generating means. FIG. 14 is a diagram illustrating another example of the back electrode according to the first embodiment.

The back electrode 1401 has a shape in which an apex portion 1401a in contact with the transfer belt 221 is bent up and down with an apex as a top. In this way, by providing the back electrode 1401 as the electric field generating means with the vertex 1401a, an electric field is generated from the position of the vertex 1401a.
Thus, the change in potential that occurs as the distance from the apex portion 1401a increases increases. As a result, the coil sensors 401a and 401c and the coil sensor 401
Even if the distances between b and 401d are slightly different, the difference between the potentials detected by the coil sensors 401a and 401c and the potentials detected by the coil sensors 401b and 401d appears remarkably. Therefore, the skew detection system can be improved.

(Embodiment 2) The flying time of the toner changes due to a change in the distance between the back electrode 223 and the small hole 259 of the developer passage control substrate 251, which affects the image quality and printing speed of the printed image. there is a possibility. Therefore, in the second embodiment, the distance (hereinafter, referred to as Li) between the FPC head unit 212 and the back electrode 223, which is an important parameter affecting the printing state, can be measured.

Specifically, Li and the coil sensor 401a
To the induced voltage generated in the coil sensors 401a to 401d, and compares the induced voltage generated in the coil sensors 401a to 401d with the value of the distance table to obtain Li.
Is calculated.

Hereinafter, an image forming apparatus according to the second embodiment will be described. The structural difference between the image forming apparatus 1500 according to the second embodiment and the image forming apparatus 1 according to the first embodiment is that the distance table 15 shown in FIG.
01 is provided. Other configurations of the image forming apparatus 1500 according to the second embodiment are the same as those of the image forming apparatus 1 according to the first embodiment, and thus the same reference numerals are given and the description will be omitted. FIG. 15 is a hardware block diagram of the image forming apparatus according to the second embodiment.

Next, a distance table 1501 which is a feature of the second embodiment will be described. Distance table 1500
Represents the voltage generated in the coil sensors 401a to 401d measured while shifting the distance between the back electrode 223 and the FPC 251 and stored as an initial value. FIG. 16 shows the relationship between the distance from the back electrode 223 to the FPC 251 and the voltage induced in the coil sensors 401a to 401d obtained by the measurement. FIG.
FIG. 9 is a diagram illustrating a relationship between a distance from a back electrode to an FPC head unit and a voltage induced in a coil sensor according to the second exemplary embodiment.

As can be seen from FIG. 16, the back electrode 22
If the distance from FPC head unit 3 to FPC head unit 212a deviates, the induced voltages generated in coil sensors 401a to 401d greatly differ. Specifically, the induced voltage is proportional to the square of the distance Li.

The image forming apparatus 1500 has the relationship between the distance Li and the voltage as the distance table 1501, so that the coil sensors 401a to 401d and the back electrode 223
The distance from a to 223d can be calculated as an actual value.

Next, the image forming apparatus 1500 according to the second embodiment calculates the distance Li (correction value) and corrects the positions of the FPC head unit 212 and the back electrode 223 according to the distance Li (correction value). Will be described with reference to FIG. FIG. 17 is a flowchart of a correction value measuring operation of the image forming apparatus according to the second embodiment.

When the image forming apparatus 1500 starts the operation of calculating the correction value (ST1700), first, the image forming apparatus 1
500 enters the measurement of the distance Li.

The image forming apparatus 1500 first
In the back electrode control unit 504, the back electrode 223 is turned on.
-OFF is performed (ST1701) to generate an electric field.
Accordingly, a voltage is induced by passing the lines of electric force through coil sensors 401a to 401d (ST1702).

Next, image forming apparatus 1500 performs the above operation a plurality of times, and averages the output values of coil sensors 401a to 401d in potential detecting section 505. Then, next, the position recognizing unit 506 executes the distance table 15
01 and the coil sensor 401a
The average value of the output of the first to fourth outputs is compared (ST1703),
The distance Li from the back surface of each of the coil sensors 401a to 401d to the back electrodes 223a to 223d is calculated (ST1704). Then, the correction value measurement unit 507 compares the distances Li with respect to each of the coil sensors 401a to 401d, thereby obtaining the coil sensors 401a to 40d.
The gap (correction value) of the distance Li between 1d is calculated (S
T1705).

Then, the positions of FPC head units 212a to 212d are adjusted according to the magnitude of the calculated correction value (ST1706). FPC head unit 21
As a means for performing the position adjustment of 2a to 212d, a ball screw method using a stepping motor or an adjustment by a screw feed amount is used as manual adjustment.

The FPC head units 212a-212
When the position adjustment of 212d is completed, image forming apparatus 1500
Enters the standby mode (ST1707) and waits for the start of the print instruction operation.

As described above, according to the second embodiment, by comparing the output values of the coil sensors 401a to 401d with the voltage values stored in the distance table 1501,
The actual distance value between the back electrode 223 and the small hole 259 can be measured without manual intervention. As a result, it is very easy to determine whether the position adjustment of the FPC head unit 212 is necessary or unnecessary. Therefore, a specifically stable image can be provided.

[0116]

As described above, according to the present invention,
By using the developer passage control substrate on which the integrally formed potential detecting element is mounted, the skew / color misregistration correction amount can be easily obtained, and the distance between the back electrode and the developer passage control substrate can be stably measured.

[Brief description of the drawings]

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

FIG. 2 is a partially enlarged view showing a configuration around a developing device and an FPC head unit of the image forming apparatus according to the first exemplary embodiment;

FIG. 3 is an enlarged view of the front and back surfaces of the FPC of the image forming apparatus according to the first embodiment;

FIG. 4 is a diagram for explaining a positional relationship between a row of small holes and a coil sensor according to the first embodiment;

FIG. 5 is a hardware block diagram of the image forming apparatus according to the first embodiment;

FIG. 6 is a diagram for explaining a skew of a row of small holes according to the first embodiment;

FIG. 7 is a flowchart of a correction value measurement of the image forming apparatus according to the first embodiment;

FIG. 8 shows ON-OFF of the back electrode according to the first embodiment.
Diagram showing the relationship between the operation and the voltage generated in the coil sensor

FIG. 9 is a first diagram illustrating an electric field between the FPC head unit and the back electrode according to the first embodiment;

FIG. 10 is a second diagram illustrating an electric field between the FPC head unit and the back electrode according to the first embodiment;

FIG. 11 is a third diagram illustrating an electric field between the FPC head unit and the back electrode according to the first embodiment;

FIG. 12 is a diagram showing another example of the positional relationship between the FPC and the coil sensor according to the first embodiment;

FIG. 13 is a diagram showing another example of the positional relationship between the FPC and the coil sensor according to the first embodiment.

FIG. 14 is a diagram showing another example of the back electrode according to the first embodiment.

FIG. 15 is a hardware block diagram of the image forming apparatus according to the second embodiment of the present invention;

FIG. 16 is a diagram showing the relationship between the distance from the back electrode to the FPC head unit and the voltage induced in the coil sensor according to the second embodiment.

FIG. 17 is a flowchart of a correction value measurement of the image forming apparatus according to the second embodiment;

FIG. 18 is a schematic diagram illustrating a configuration of a conventional image forming apparatus.

DESCRIPTION OF SYMBOLS 1, 1500 Image forming apparatus 20 Image forming unit 30 Transfer unit 210 Developing units 212a to 212d FPC head unit 214a to 214d Developing roller 221 Transfer belt 223a to 223d, 1401 Back electrode 259 Small hole 260 Small hole array 261 Image signal electrode 264 Vibration plate 265 Ultrasonic vibration generator 266 Toner supply roller 267 Toner regulating blade 300 Lead wire 301 Transfer roller 302 Recording paper guide 304 Solenoid 401a to 401d, 1201a to 1201f, 130
1a to 1301d Coil sensor 501 CPU 504 Back electrode control unit 505 Potential detection unit 506 Position recognition unit 507 Correction value measurement unit 508 Skew correction unit 1501 Distance table

Claims (7)

[Claims] A developing device for supporting and transporting a developer; forming a small hole array including a plurality of small holes arranged near the developer carrying member and through which the developer passes; A developer passage control substrate for controlling the passage of the developer through the small holes, and a back electrode that is disposed opposite to the developer passage control substrate and generates an electric field for causing the developer to fly between the developer carrier. An image receiving member that is arranged between the developer passage control substrate and the back electrode and forms an image by the developer passing through the small hole adhering to the surface; and an image receiving member on the developer passage control substrate. A potential detecting element for detecting the intensity of the electric field generated by the back electrode as a potential; and position recognition for recognizing a positional relationship between the developer passage control substrate and the back electrode based on a detection result of the potential detecting element. And means An image forming apparatus comprising: 2. A distance storage means for storing a plurality of sets of the potential detected by the potential detection element and a distance between the developer passage control substrate and the back electrode corresponding to the potential, wherein the distance storage is provided. 2. The image forming apparatus according to claim 1, wherein a distance between the developer passage control substrate and the back electrode corresponding to the potential detected by the potential detecting element is recognized by referring to a unit. 3. The device according to claim 1, wherein the plurality of potential detecting elements are arranged symmetrically with respect to the row of small holes.
Alternatively, the image forming apparatus according to claim 2. 4. The image forming apparatus according to claim 3, wherein the inclination of the row of small holes with respect to the back electrode is recognized by comparing the potentials detected by the plurality of potential detection elements. 5. The electric potential detecting element according to claim 1, wherein the electric potential detecting element is a coil sensor, and the electric potential is generated in the coil sensor by repeating generation and disappearance of the electric field by the back electrode. An image forming apparatus according to any one of the above. 6. The device according to claim 1, wherein the potential detection element is formed integrally with the developer passage control substrate.
An image forming apparatus according to any one of claims 1 to 5. 7. A developer carrying member for carrying and transporting a developer, and a small hole array formed of a plurality of small holes arranged near the developer carrying member and through which the developer passes, and the developer is formed. A developing unit having a developer passage control substrate for controlling the passage of the small holes, and an image being formed by disposing the developer on the surface of the developer unit, the developer unit being disposed opposite to the developer passage control substrate of the developing unit. An image forming apparatus having a plurality of pairs of a back electrode for generating an electric field for causing the developer to fly on an image receiving member and the developer carrier, in accordance with the number of colors of the developer. A comparison is made between a plurality of potential detecting elements that detect the strength of the electric field generated by the back electrode disposed on the developer passage control board of the developing unit as potentials and the potentials detected by the plurality of potential detecting elements. To do An image forming apparatus characterized by including a position recognizing means for recognizing the positional relationship between the developer passing controller board the back electrode of the developing unit of the respective.