JP2003241515A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the consumption of a developer and the deterioration of a cleaning member in an image forming apparatus. <P>SOLUTION: By generating bias in the moving direction of toner from an intermediate transfer belt 26 to a photoreceptor belt 22, transferring of the toner for forming a patch from the photoreceptor belt 22 to the intermediate transfer belt 26 is regulated. By bringing the development roller 18 of a development cartridge 15 into contact with the photoreceptor belt 22 while generating bias in the moving direction of the toner to the development cartridge 15, the tonner is collected to the original development cartridge 15. Thus, in the case of forming the path, etc., the toner can easily be collected, so that the reduction of the toner is suppressed. Since it is less necessary to remove the toner for forming the patch by the cleaning member, the deterioration of the cleaning member can be suppressed. <P>COPYRIGHT: (C)2003,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 for forming an image by transferring a developer image formed on an image carrier by a developer supplied from a developing device to a transfer medium. .

[0002]

2. Description of the Related Art Conventionally, a developer image formed on an image bearing member by a developer supplied from a developing unit is transferred to a transfer medium (which can carry the developer image by transfer. For example, an intermediate transfer belt, recording. In an image forming apparatus that forms an image by transferring the image onto a sheet), in order to appropriately adjust the image density, an image for density detection (so-called patch) having various density patterns on the image carrier is formed. Calibration is performed by forming a patch, measuring the density of this patch with an optical density sensor, and controlling process conditions (for example, developing bias value) based on the result. In this case, the developer used for forming the patch is generally removed from the image carrier by a predetermined cleaning member.

[0003]

By the way, in the above technique, there is a problem that the developer is consumed quickly because the patch is formed. Further, since the amount of the developer to be removed from the image bearing member after forming the patch is larger than the amount of the developer remaining on the image bearing member after the transfer from the image bearing member to the transfer medium, this amount should be used as a cleaning member. Even if it is removed by, there is a problem that the cleaning performance deteriorates quickly.

The present invention has been made in view of these problems, and an object thereof is to make it possible to suppress consumption of a developer and deterioration of a cleaning member in an image forming apparatus.

[0005]

Means for Solving the Problems and Effects of the Invention In the image forming apparatus of the present invention (claim 1) made to solve the above problems, the regulating means develops from the image carrier to the transfer medium. The collecting unit collects the developer, which has been regulated from moving from the image carrier to the transfer medium by the regulating unit, from the image carrier to the developing unit.

That is, the image forming apparatus according to the first aspect regulates the movement of the developer from the image carrier to the transfer medium (in other words, the transfer of the developer image), and the development in which the movement is regulated. The agent can be collected from the image carrier to the developing device. Therefore, when the developer is used for a purpose other than the normal printing operation (for example, when forming a patch), the developer can be reused and the consumption amount thereof can be suppressed. Moreover, since the developer carried on the image carrier is collected by the developing device, it is not necessary to use a cleaning member to remove it from the image carrier, or the cleaning member removes a small amount of developer. Therefore, deterioration of the cleaning member can be suppressed.

As a method of recovering the developer to the developing device, for example, as described in claim 2, it is considered that a bias is generated in the developing device in a direction in which the developer moves. Generally, in an image forming apparatus that forms an image by transferring a developer image formed on an image bearing member by a developer supplied from a developing device to a transfer medium,
The developer is positively or negatively charged in the developing device, and a bias is applied so that the developer is transferred from the developing device to the image carrier, so that the developer is transferred from the image carrier to the transfer medium. A bias is also applied to. In other words, by switching the bias to be applied, it is possible to easily collect the developer by applying a bias in a direction opposite to that in the normal image formation, in other words, in the direction in which the developer goes from the image carrier to the developing device. Can be done in a configuration.

Further, as described in claim 3, the developing device is
When the non-magnetic one-component toner is stored as the developer and the developer is supplied by the contact developing method, the developer can be easily collected by bringing the developing device into contact with the photoconductor. . On the other hand, in order to regulate the movement (transfer) of the developer from the image carrier to the transfer medium, for example, as described in claim 4, a bias is applied in the direction in which the developer moves from the transfer medium to the image carrier. A method of generating it can be considered. According to the image forming apparatus of claim 4 configured as described above,
With a simple configuration, the movement (transfer) of the developer from the image carrier to the transfer medium can be regulated. As described above, in general, when an image is formed, a bias is applied so that the developer moves from the image bearing member to the transfer medium. Therefore, only by applying a reverse bias to the bias, the developer is transferred to the transfer medium. From the image carrier to the image carrier, the transfer from the image carrier to the transfer medium is regulated.

It is also conceivable that the transfer medium and the image carrier are separated from each other so as to regulate the movement of the developer from the image carrier to the transfer medium. According to the image forming apparatus of the fifth aspect configured as described above, it is possible to more reliably regulate the movement of the developer.

By the way, in a normal printing operation of the image forming apparatus, after the developer image formed on the image carrier is transferred to the transfer medium, the developer remaining on the image carrier is removed. In some cases, cleaning means may be provided. In such a case, as described in claim 6, the cleaning unit removes the developer from the image carrier while the regulation unit regulates the movement of the developer from the image carrier to the transfer medium. It is advisable to provide a prohibition means that prohibits such actions. According to the image forming apparatus of the sixth aspect configured as described above, it is possible to collect the developer in the developing device without accelerating the deterioration of the cleaning performance of the cleaning unit.

According to the above-mentioned constitutions of claims 1 to 6, as described in claim 7, the image carrier is inspected by the developer supplied from the developing device (that is, the inspection of the supply characteristic of the developer). The present invention can be applied to an image forming apparatus provided with a patch forming means for forming a patch for use. That is, the regulation means is configured to regulate the movement of the developer supplied from the developing device to form the patch from the image carrier to the transfer medium, and the developer is supplied from the developing device to form the patch. By configuring the recovery means so as to recover the developed developer from the image bearing member to the developing device, it is possible to prevent the developer from being rapidly reduced even when patch formation is performed. In addition, deterioration of the cleaning member can be suppressed.

When a plurality of developing devices for supplying developers of different colors are provided as described in claim 8,
The collecting unit may be configured to collect the developer, which is supplied from any one of the developing devices and whose movement from the image carrier is restricted to the transfer medium, into the supplied developing device. According to the image forming apparatus of the eighth aspect configured as described above, it is possible to collect the developers while preventing the developers of different colors from being mixed with each other.

Further, the patch forming means is configured so that the developer is supplied from each of the plurality of developing devices while the image bearing member makes one revolution, and a patch for measuring the supply characteristic of each developer is formed. Good to do. According to the image forming apparatus of the ninth aspect configured as described above, it is possible to quickly measure the supply characteristic of each developer onto the image carrier.

The image bearing member may be, for example, a member directly receiving the supply of the developer from the developing device (for example, a photoconductor), or a developer image formed on another image bearing member is transferred. As a result, an image carrier (for example, an intermediate transfer member) capable of carrying a developer image can be considered.

Therefore, as described in claim 10, the image bearing member (described in claims 1 to 9) transfers the developer image formed on another image bearing member to form a developer image. In the case of an image carrier to be carried, the collecting device is configured to use a developer whose transfer from the image carrier to the transfer medium is restricted by the restricting device to the developing device via the other image carrier. It may be configured to be collected at.

If a patch is formed on the image carrier that will carry the developer image by transferring the developer image formed on another image carrier, the developer supply characteristic can be improved. It will be possible to measure in a form that reflects the transfer efficiency.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically showing a mechanical configuration of a color laser printer 1 as an image forming apparatus of the first embodiment, and FIG. 2 is a diagram schematically showing an electrical configuration of the color laser printer 1. Is.

In FIG. 1, the color laser printer 1 includes a main body casing 2 and a paper 3 as a recording medium.
A sheet feeding section 4 for feeding a sheet, an image forming section 5 for forming a predetermined image on the fed sheet 3, and the like are provided. The paper feeding unit 4 includes a paper feeding tray 6 and a paper feeding roller 7, and the paper 3 is stacked on the paper feeding tray 6 in the paper feeding unit 4. Then, the topmost sheet 3 of the sheet feed tray 6
The sheets are fed one by one by the rotation of the sheet feeding roller 7, and are conveyed to the image forming section 5 by the conveying roller 8 and the registration roller 9.

The image forming section 5 includes a scanner unit 10,
A process unit 11, an intermediate transfer belt mechanism unit 12, a transfer roller 13, a fixing unit 14, and the like are provided. The scanner unit 10 as an exposing unit is provided with a laser emitting section (not shown), a polygon mirror, a plurality of lenses, and a reflecting mirror in the central portion of the main body casing 2. In the scanner unit 10, a laser beam based on predetermined image data emitted from the laser emitting section is passed or reflected through a polygon mirror, a reflecting mirror and a lens, and a photosensitive belt mechanism section 16 described later is provided. High-speed scanning is performed on the surface of the photosensitive belt 22 (which is an example of a photoconductor on which an electrostatic latent image is formed by exposure and corresponds to the “image carrier” in the claims).

The process section 11 includes a developing cartridge 15
(15Y, 15M, 15C, 15K), a photosensitive belt mechanism 16 and a scorotron charger 17 are provided. In this embodiment, four developing cartridges 15 are provided, and specifically, a yellow developing cartridge 15Y for supplying yellow toner, a magenta developing cartridge 15M for supplying magenta toner, and a cyan developing cartridge, respectively. The cyan developing cartridge 15C for supplying the black toner and the black developing cartridge 15K for supplying the black toner. These developing cartridges 15 are sequentially arranged in parallel in the vertical direction on the rear side of the main body casing 2 at predetermined intervals in the vertical direction.

Each developing cartridge 15 is provided with a developing roller 18, a layer thickness regulating blade (not shown), a supply roller, a toner accommodating portion, etc., and each developing roller 18 is brought into contact with or separated from the surface of a photosensitive belt 22 described later. So that the developing cartridge drive unit 60
It is configured to be movable horizontally.

As shown in FIG. 2, the developing cartridge drive unit 60 operates according to a control signal from the CPU 51, and has a developing device contact / separation mechanism including a motor and a clutch (not shown). The developing device contacting / separating mechanism is provided for each developing cartridge 15 (developing device), and the developing cartridge 15 is developed from the photosensitive belt 22 and the developing position where the developing roller 18 contacts the photosensitive belt 22 by the driving of the motor. The roller 18 is moved to a separated position where the roller 18 is separated. Further, in synchronism with the revolving movement of the photosensitive belt 22, the developing roller 18 moved to the developing position is rotationally driven by the motor so that the developer carried by the electrostatic force on the developing roller 18 is electrostatically charged on the photosensitive belt 22. A developing roller drive mechanism that supplies the latent image to the surface is also provided in the developing roller drive unit 60 for each developing cartridge 15. A yellow developing cartridge 15Y, a magenta developing cartridge 15M, a cyan developing cartridge 15C, and a black developing cartridge 15K are connected to the developing cartridge driving section 60, and a developing device contact / separation mechanism including a motor and a clutch not shown, The developing roller drive mechanism or the like allows each developing cartridge 15 to move in the horizontal front-rear direction, that is, the contacting / separating direction, and the developing roller 18 to be rotationally driven.

The toner storage portion of each developing cartridge 15 stores positively charged non-magnetic one-component polymerized toner as a developer of each color of yellow, magenta, cyan and black, and supplies the toner. When the toner is supplied to the developing roller 18 by the rotation of the roller, it is carried on the developing roller 18 as a thin layer having a constant thickness by the layer thickness regulating blade. At this time, the toner is charged and is carried on the developing roller 18 by an electrostatic force.

A developing bias applying circuit 54 is connected to the developing roller 18 of the developing cartridge 15 (see FIG. 2). The developing bias applying circuit 54 includes the CPU 5
The output voltage can be changed to be higher or lower than the surface potential of the photosensitive belt 22 in accordance with the control signal from 1. For example, a bias is generated in a direction in which toner moves from the developing cartridge 15 to the photosensitive belt 22. Alternatively, a bias can be generated in the direction in which the toner moves from the photosensitive belt 22 to the developing cartridge 15. When a negatively chargeable toner is used, a bias reverse to that of the positively chargeable toner may be applied.

The photosensitive belt mechanism section 16 is disposed on the front side of the four developing cartridges 15 so as to face each other, and the first photosensitive belt roller 19 disposed substantially opposite to the black developing cartridge 15K. The second photosensitive belt roller 20 that is disposed substantially vertically above and in opposition to the uppermost yellow developing cartridge 15Y.
And a third photosensitive belt roller 21 as a moving support member which is disposed above the first photosensitive belt roller 19 and diagonally below the second photosensitive belt roller 20.
And a photosensitive belt 22 wound around the first photosensitive belt roller 19 to the third photosensitive belt roller 21.

The first photosensitive belt roller 19 to the third photosensitive belt roller 21 are arranged in a triangular shape, and are provided inside the photosensitive belt 22 so as to come into contact with the photosensitive belt 22. The photosensitive belt 22 is an endless belt made of a resin such as PET (polyethylene terephthalate) having aluminum vapor-deposited on its surface, and has an organic photosensitive layer on its surface. The photosensitive belt 22 is rotated by the second photosensitive belt roller 20 being driven by the main drive unit 55 (moves counterclockwise in FIG. 1).

As shown in FIG. 2, the main drive section 55 has a CP
It operates in accordance with a control signal from U51 and has a main motor (not shown). The second photosensitive belt roller 20 is connected to the main motor via a gear train (not shown). Then, the second photosensitive belt roller 20 is rotationally driven by the main motor, and
As the first photosensitive belt roller 19 and the third photosensitive belt roller 21 are driven, the photosensitive belt 22 rotates.

The main motor includes a first intermediate transfer belt roller 2 which will be described later and which constitutes the intermediate transfer belt mechanism section 12.
3 is connected, paper feed roller 7, transfer roller 1
A drive unit (not shown) for driving the device 3 and the like is connected. A density sensor 39 for detecting the optical density of the toner image (developer image) formed on the photosensitive belt 22 is arranged above the second photosensitive belt roller 20 and near the photosensitive belt 22. The detection signal from the density sensor 39 is input to the CPU 51 as shown in FIG.

Next, the intermediate transfer belt mechanism section 12 is arranged on the front side of the photosensitive belt mechanism section 16 and faces the second photosensitive belt roller 20 via the photosensitive belt 22 and an intermediate transfer belt 26 described later. The first intermediate transfer belt roller 23 that is arranged, and the second intermediate transfer belt roller that is obliquely below the first intermediate transfer belt roller 23 and is opposed to the transfer roller 13 described later via the intermediate transfer belt 26. 24, a third intermediate transfer belt roller 25 disposed above the second intermediate transfer belt roller 24 and obliquely below the first intermediate transfer belt roller 23, and a first intermediate transfer belt roller 25.
The intermediate transfer belt roller 23 to the third intermediate transfer belt roller 25 are wound around the intermediate transfer belt 26.

The intermediate transfer belt 26 is an endless belt made of a resin such as conductive polycarbonate or polyimide in which a conductive material such as carbon is dispersed. The intermediate transfer belt 26 has a main drive unit 55.
The first intermediate transfer belt roller 23 is driven to rotate by the driving of the first intermediate transfer belt roller 23, and the second intermediate transfer belt roller 24 and the third intermediate transfer belt roller 25 are driven by the first intermediate transfer belt roller 23,
It moves around the intermediate transfer belt roller 23 to the third intermediate transfer belt roller 25 (clockwise in FIG. 1).

Further, as shown in FIG. 2, a primary transfer bias applying circuit 53 is connected to the intermediate transfer belt mechanism section 12. The primary transfer bias applying circuit 53 is a CPU
According to the control signal from 51, the output voltage is set to the photosensitive belt 2
The surface potential of the intermediate transfer belt 2 is set to be higher or lower than that of the photosensitive belt 22.
It is possible to generate a bias in the direction in which the toner is transferred to 6, or to generate a bias in the direction in which the toner is transferred from the intermediate transfer belt 26 to the photosensitive belt 22. In the case of negatively charged toner, the bias is reversed.

Next, the transfer roller 13 is arranged at a position facing the second intermediate transfer belt roller 24 with the intermediate transfer belt 26 interposed therebetween. The transfer roller 13 is provided so as to be in contact with and separated from the surface of the intermediate transfer belt 26 by the transfer roller driving unit 61, and when the sheet 3 is conveyed,
The intermediate transfer belt 26 is contacted and a predetermined transfer bias is applied. The color image formed on the intermediate transfer belt 26 is transferred (so-called secondary transfer) to the sheet 3 passing between the intermediate transfer belt 26 and the transfer roller 13 after the transfer roller 13 contacts the intermediate transfer belt 26. Will be.

The scorotron charger 17 is located below the photosensitive belt mechanism portion 16 and is located at the third photosensitive belt roller 21.
The first photosensitive belt roller 19 and the first photosensitive belt roller 19 are arranged at a predetermined interval so as not to contact the photosensitive belt 22. The scorotron type charger 17 is a scorotron type charger for positive charging that generates corona discharge from a charging wire such as tungsten.
Is uniformly charged to the positive polarity.

The surface of the photosensitive belt 22 is uniformly positively charged by the scorotron charger 17, and then exposed by high-speed scanning of the laser beam from the scanner unit 10, and electrostatically based on predetermined image data. A latent image is formed on the image forming area. Then, the developing roller 18 of the specific developing cartridge 15 to which a predetermined developing bias is applied is brought into contact with the photosensitive belt 22 on which the electrostatic latent image is formed, so that an image forming area of the photosensitive belt 22 is formed.
A monochromatic visible image (toner image) accommodated in the specific developing cartridge 15 is formed.

Further, the photosensitive belt 22 and the intermediate transfer belt 26
In between, the primary transfer bias is applied at a predetermined timing so that the toner image is transferred from the photosensitive belt 22 to the intermediate transfer belt 26 (so-called primary transfer). The formed single-color visible image is sequentially superposed on the intermediate transfer belt 26 when the photosensitive belt 22 and the intermediate transfer belt 26 face the intermediate transfer belt 26 at a transfer position where they are in contact with each other. As a result, a color image is formed on the intermediate transfer belt 26.

The fixing unit 14 is an intermediate transfer belt mechanism unit 12.
A heating roller 27 and a pressing roller 28 that presses the heating roller 27 are provided on the front side of the heating roller 27. 1 is provided on the downstream side of the heating roller 27 and the pressing roller 28.
A pair of transport rollers 29 is provided.

The heating roller 27 has a silicone rubber outer layer,
The inner layer is made of metal, and a halogen lamp is provided inside the roller as a heat source. The color image transferred onto the paper 3 is thermally fixed while the paper 3 passes between the heating roller 27 and the pressing roller 28. Let

The sheet 3 on which the color image has been heat-fixed in the fixing section 14 is conveyed by the conveying roller 29 toward the pair of sheet discharging rollers 30 and further discharged by the sheet discharging roller 30 of the main body casing 2. The sheet is discharged onto the sheet discharge tray 31 formed on the upper portion.

In the color laser printer 1, after the primary transfer to the intermediate transfer belt 26, the photosensitive belt 2 is
A photosensitive belt cleaning device 33 is provided for removing the residual toner remaining on the surface of No. 2. The photosensitive belt cleaning device 33 includes a photosensitive belt mechanism unit 1
6, on the opposite side of each developing cartridge 15,
Second photosensitive belt roller 20 and third photosensitive belt roller 21
Between the third photosensitive belt roller 21, the photosensitive belt cleaning box 34, the photosensitive belt cleaning roller 35, the secondary photosensitive belt cleaning roller 35a, and the photosensitive belt cleaning blade 35b.

The photosensitive belt cleaning box 34 is
An opening is formed in a part on the side facing the photosensitive belt 22 in the shape of a box, and the lower space inside thereof is a waste toner storage that stores the toner scraped by the photosensitive belt cleaning blade 35b. Is formed as a part.

The photosensitive belt cleaning roller 35 is made of an elastic material such as silicone rubber, is rotatably supported at the opening of the photosensitive belt cleaning box 34, and near the third photosensitive belt roller 21.
The photosensitive belt 22 comes into contact with the outside of the photosensitive belt 22.
It is arranged so as to rotate in the same direction as the photosensitive belt 22 (clockwise in FIG. 1) at the contact portion with.

Further, the photosensitive belt cleaning roller 35
Is provided so as to be able to come into contact with and separate from (contact with and separate from) the photosensitive belt 22 by the photosensitive belt cleaning roller driving unit 56, and the toner on the photosensitive belt 22 is removed by the bias applying circuit (not shown).
A bias (cleaning bias) can be applied in the direction of transfer to the photosensitive belt cleaning roller 35.

When the photosensitive belt cleaning roller 35 to which the cleaning bias is applied is in contact with the photosensitive belt 22, the intermediate transfer belt 2 is developed at the time of development for each color.
The toner remaining on the photosensitive belt 22 after the transfer of the toner image to 6 is electrically removed by the photosensitive belt cleaning roller 35 when the photosensitive belt 22 faces the photosensitive belt cleaning roller 35 due to the movement of the photosensitive belt 22.

Secondary photosensitive belt cleaning roller 35a
Is a roller made of metal, on the side opposite to the photosensitive belt 22 with respect to the photosensitive belt cleaning roller 35,
The photosensitive belt cleaning roller 35 is arranged so as to face the photosensitive belt cleaning roller 35.
A predetermined bias is applied to.

Photosensitive belt cleaning blade 35b
Is a thin plate-shaped scraping blade that is arranged to face the secondary photosensitive belt cleaning roller 35a on the side opposite to the photosensitive belt cleaning roller 35 so as to contact the secondary photosensitive belt cleaning roller 35a. Secondary photosensitive belt cleaning roller 35a
It is configured to scrape off the toner attached on the surface of the.

During the development of each color, the residual toner of each color remaining on the photosensitive belt 22 after the transfer to the intermediate transfer belt 26, when the photosensitive belt 22 moves to face the photosensitive belt cleaning roller 35, It is electrically captured by the photosensitive belt cleaning roller 35. After that, the captured toner is electrically captured by the secondary photosensitive belt cleaning roller 35a when it opposes the secondary photosensitive belt cleaning roller 35a due to the rolling of the photosensitive belt cleaning roller 35. Belt cleaning blade 3
It is scraped off by 5b and stored in the waste toner reservoir.

As shown in FIG. 2, the photosensitive belt cleaning roller drive unit 56 operates in accordance with a control signal from the CPU 51, and moves the photosensitive belt cleaning roller 35 to contact and separate from the photosensitive belt 22. Is configured to be able to.

Further, the color laser printer 1 is provided with an intermediate transfer belt cleaning device 36 for collecting the toner remaining on the surface of the intermediate transfer belt 26 after the transfer onto the sheet 3. The intermediate transfer belt cleaning device 36 is located on the side of the intermediate transfer belt mechanism unit 12, and includes the third intermediate transfer belt roller 25 and the intermediate transfer belt 2.
It is arranged at a position facing each other through 6. The intermediate transfer belt cleaning device 36 includes an intermediate transfer belt cleaning box 37, an intermediate transfer belt cleaning roller 38, a secondary intermediate transfer belt cleaning roller 38a, and an intermediate transfer belt cleaning blade 38b.
It has and.

Intermediate transfer belt cleaning box 37
Has a box shape, and an opening is formed in a part of the side facing the intermediate transfer belt 261, and a lower space inside the opening has an intermediate transfer belt cleaning blade 3 described later.
It is formed as a waste toner storage portion for storing the toner scraped off by 8b.

Intermediate transfer belt cleaning roller 38
Is made of an elastic material such as silicone rubber, and is rotatably supported at the opening of the intermediate transfer belt cleaning box 37. The third intermediate transfer belt roller is driven by the intermediate transfer belt cleaning roller drive unit 57 (see FIG. 2). 25 at the position facing the intermediate transfer belt 26.
It is arranged so as to contact with and separate from.

This intermediate transfer belt cleaning roller 3
The intermediate transfer belt 8 is separated from the intermediate transfer belt 26 by a predetermined distance until the above four color toners (yellow, magenta, cyan and black) are transferred onto the intermediate transfer belt 26. When the color images on the sheet 26 are collectively transferred to the sheet 3, the intermediate transfer belt 26 is contacted. A predetermined cleaning bias is applied between the intermediate transfer belt cleaning roller 38 and the intermediate transfer belt 26 so that the toner is transferred from the intermediate transfer belt 26 to the intermediate transfer belt cleaning roller 38.

When the color image is transferred, the toner remaining on the intermediate transfer belt 26 after the transfer onto the paper 3 is transferred to the intermediate transfer belt cleaning roller 38 by the rotation of the intermediate transfer belt 26, and the intermediate toner is transferred to the intermediate position. It is captured by the transfer belt cleaning roller 38. After that, the captured toner is captured by the secondary intermediate transfer belt cleaning roller 38a when the intermediate transfer belt cleaning roller 38 faces the secondary intermediate transfer belt cleaning roller 38a by the rotation of the intermediate transfer belt cleaning roller 38, and then the intermediate transfer belt cleaning roller 38a. Belt cleaning blade 3
It is scraped off by 8b and stored in the toner storage section.

The intermediate transfer belt cleaning roller drive unit 57 operates according to a control signal from the CPU 51, as shown in FIG. 2, and moves the intermediate transfer belt cleaning roller 38 to contact the intermediate transfer belt 26. And can be separated from each other.

As shown in FIG. 2, in the color laser printer 1, the CPU 51 includes a density sensor 39, a developing bias applying circuit 54, a main drive unit 55, a photosensitive belt cleaning roller drive unit 56, and an intermediate transfer belt cleaning roller drive. The unit 57, the developing cartridge drive unit 60, etc. are connected.

The CPU 51 has a RAM 58 and a ROM 5
9 is provided to execute control of each unit, and the RAM 5
The numeral 8 temporarily stores numerical values and image data input from the density sensor 39 and the like. Also, the ROM 59
Includes a primary transfer bias applying circuit 53 and a main drive unit 5.
5. The control program for controlling the developing cartridge drive unit 60 and the like is stored, and the density sensor 39
A sensor output / density conversion table 59a for converting the output signal from the sensor into a density, and a density / development bias conversion table 59b for determining the correction amount of the developing bias according to the difference between the detected density and the specified density. The table is also stored.

The calibration operation performed in the color laser printer 1 of the present embodiment configured as described above will be described with reference to a flow chart and a time chart. During the calibration, the photosensitive belt cleaning roller drive unit 56 keeps the photosensitive belt cleaning roller 35 away from the photosensitive belt 22.

As shown in the flow chart of FIG. 3, first, the setting of the color to be developed is initialized (S10). That is, the color of the patch to be developed first is set. Next, the patch is developed using the toner of the set color (S2
0). That is, first, the surface of the photosensitive belt 22 is uniformly positively charged by the scorotron charger 17, and is exposed by high-speed scanning of the laser beam from the scanner unit 10 to form an electrostatic latent image for forming a patch. Are formed on the photosensitive belt 22. As a result, the potential of the unexposed area is about 800 V (referenced to ground; the same applies below), and the potential of the exposed area (electrostatic latent image) is about 200 V.

Then, with the developing roller 18 of the developing cartridge 15 for storing the toner of the set color being in contact with the photosensitive belt 22 (FIG. 4: t1 to t4), a voltage of about 500 V is applied to the developing roller 18. Apply Vb (ie
By applying a developing bias) (Fig. 4: t2-t
3) The toner is moved from the developing cartridge 15 to the photosensitive belt 22 to form the patch of the set color (S20).

The density of the patch formed in this way is detected by the density sensor 39 when the patch faces the density sensor 39 due to the circular movement of the photosensitive belt 22 (S30). That is, from the density sensor 39 to C
The detection signal input to the PU 51 is converted into density by the sensor output / density conversion table 59a.

Thereafter, the patch opposes the intermediate transfer belt 26 at the position where the photosensitive belt 22 and the intermediate transfer belt 26 contact each other. The potential Vt of the intermediate transfer belt 26 is the primary transfer bias applying circuit 53. Is set to about 500V in advance (FIG. 4: t0 to t6) and is higher than the potential of the patch formation area of the photosensitive belt 22 (that is, about 200V), the toner from the photosensitive belt 22 to the intermediate transfer belt 26 is Movement is regulated.

After the density of the patch is detected, the toner used for forming the patch is replaced with the original developing cartridge 1.
5 (S40). For example, when toner is supplied from the yellow developing cartridge 15Y to form a patch, the toner is collected in the yellow developing cartridge 15Y.

Specifically, with the developing cartridge 15 in contact with the photosensitive belt 22, the voltage Vb applied to the developing roller 18 is set to about -100 V (FIG. 4: t3 to t).
5) By lowering the voltage Vb applied to the developing roller 18 below the potential of the photosensitive belt 22 (about 0 V), the toner is moved to the developing cartridge 15 (S4).
0). The potential of the photosensitive belt 22 is
An erase lamp (not shown) that irradiates the surface with light to erase the residual electric charge causes about 0 V.

The patch collection is completed by separating the developing cartridge 15 from the photosensitive belt 22 while keeping the voltage Vb applied to the developing roller 18 at about -100V (FIG. 4: t4). The voltage Vb applied to the developing roller 18 is set to 0V after the developing cartridge 15 is separated from the photosensitive belt 22 (FIG. 4: t5).

When the patches are collected as described above (S4
0) Next, it is determined whether or not the density of the patch detected as described above is the specified density (S50). When the detected density is not the specified density (S50: NO), the magnitude of the developing bias to be applied to the developing roller 18 is changed based on the density / developing bias conversion table 59b (S6).
0), patch development using the same color developing cartridge 15 (S20), density detection (S30), and patch collection (S40) are repeated until the detected density reaches the specified density.

When it is determined that the detected density is the specified density (S50: YES), it is determined whether the color of the developing cartridge 15 used immediately before is the final color (S70). For example, if patch density detection is performed in the order of yellow, magenta, cyan, and black, the patch development (S2
0) etc. are judged.

If it is not the final color (S70: NO), the color to be developed is changed to the next color (S80), and the same processing is performed for the developing cartridge 15 of that color (S20-S).
70). That is, as shown in FIG. 4, after the calibration of the first color is performed, the calibrations of the second color, the third color, and the fourth color are sequentially performed.

On the other hand, if it is the final color (S70: Y)
ES) and the calibration is completed. In this embodiment, the developing cartridge 15 corresponds to the "developing device" in the claims, and the photosensitive belt 22 corresponds to the "image carrier" in the claims.
And the intermediate transfer belt 26 corresponds to the "transfer medium" in the claims.
Equivalent to. Further, the CPU 51 and the primary transfer bias applying circuit 53 function as "regulating means" in the claims, and C
The PU 51, the developing bias applying circuit 54, and the developing cartridge driving unit 60 function as "collecting means" in the claims (S40). Further, the photosensitive belt cleaning device 33
Corresponds to the "cleaning unit" in the claims, and the CPU 51 and the photosensitive belt cleaning roller driving unit 56 function as the "inhibition unit" in the claims.
The processing of S20 performed by 51 is the "patch forming means" in the claims.
Is functioning as.

As described above, in the color laser printer 1 of this embodiment, the bias for generating toner in the direction in which the toner moves from the intermediate transfer belt 26 to the photosensitive belt 22 causes the toner for patch formation to be transferred to the photosensitive belt 22. Transfer from the intermediate transfer belt 26 to the intermediate transfer belt 26, and
The toner is collected in the original developing cartridge 15 by bringing the developing roller 18 of the developing cartridge 15 into contact with the photosensitive belt 22 while generating a bias in the direction in which the toner moves in the developing cartridge 15. Therefore, the toner can be easily collected even when the calibration using the patch is performed, and as a result, the toner decrease can be suppressed. Further, since it is less necessary to remove the toner for forming the patch with the cleaning member, it is possible to suppress the deterioration of the cleaning member.

The color laser printer 1 of this embodiment is also used.
In the above, since the developing cartridge 15 stores the non-magnetic one-component toner as the developer and supplies the toner by the contact developing method, the developing cartridge 1
It is easy to bring the developing roller 18 of No. 5 into contact with the photosensitive belt 22, and toner is easily collected.

The color laser printer 1 of this embodiment is also used.
In order to regulate the movement of toner from the photosensitive belt 22 to the intermediate transfer belt 26, the intermediate transfer belt 26
A bias is generated on the photosensitive belt 22 in the direction in which the toner moves. Therefore, it is possible to regulate the movement of the toner from the photosensitive belt 22 to the intermediate transfer belt 26 with a simple configuration.

The color laser printer 1 of this embodiment is also used.
In FIG. 3, a photosensitive belt cleaning device 33 for removing the toner remaining on the photosensitive belt 22 after the primary transfer is provided, but during the calibration (that is, the toner from the photosensitive belt 22 to the intermediate transfer belt 26 is removed). While the movement is restricted), the photosensitive belt 22 is separated and it is prohibited to remove the toner from the photosensitive belt 22. Therefore, the deterioration of the cleaning performance of the photosensitive belt cleaning device 33 is not accelerated,
Moreover, it does not prevent the toner from being collected in the developing cartridge 15.

The color laser printer 1 of this embodiment is also used.
In the above, a plurality of developing cartridges 15 for supplying toner of different colors are provided. However, the toner supplied from any of the developing cartridges 15 and the movement of which is restricted from the photosensitive belt 22 to the intermediate transfer belt 26 is It is collected in the developing cartridge 15 (that is, the supplied developing cartridge 15). Therefore, it is possible to collect and reuse the toner while preventing the toners of different colors from being mixed with each other.

Next, the second embodiment will be described. In the first embodiment described above, only one color patch is formed while the photosensitive belt 22 makes one revolution. In the second embodiment, a plurality of colors are formed while the photosensitive belt 22 makes one revolution. To form a patch. The configuration and operation of this embodiment other than those particularly described are the same as those of the first embodiment, and therefore the same reference numerals are given and the description thereof is omitted.

Now, as shown in FIGS. 5 and 6, in the calibration of the color laser printer 1 of the present embodiment, the photosensitive belt 22 makes one round for the development of the patches of each color from the first color to the fourth color. In between (S110). That is,
First, on the surface of the photosensitive belt 22 on which the electrostatic latent image is formed,
The developing cartridge 15 for the first color is brought into contact (see FIG. 6: t1 to
t4), a developing bias (about 500
V) is applied (FIG. 6: t2 to t3) to form a patch of the first color. Then, as shown in FIG. 6, while the photosensitive belt 22 makes one round, formation of patches for the second, third, and fourth colors is performed in the same manner. That is, the patches of a plurality of colors are formed on the photosensitive belt 22 at the same time.

The densities of the patches of the respective colors formed in this manner are detected by the density sensor 39 when the patches face the density sensor 39 due to the circular movement of the photosensitive belt 22 (S120). The potential Vt of the intermediate transfer belt 26 is set to about 500 V by the primary transfer bias applying circuit 53 as in the first embodiment (FIG. 6: t0 to t9), and the patch on the photosensitive belt 22 is formed. Since the potential is higher than the potential of the area (that is, about 200 V), the movement of the toner from the photosensitive belt 22 to the intermediate transfer belt 26 is restricted.

After the density of each patch is detected, the toner used for forming each patch is collected in each original developing cartridge 15 (S130). First, with the voltage Vb applied to the developing roller 18 for the first color set to about −100 V (FIG. 6: t5 to t8), this developing roller 18 is moved to the photosensitive belt 2
The toner of the first color is collected in the original developing cartridge 15 by bringing it into contact with 2 (FIG. 6: t6 to t7). Then, as shown in FIG. 6, after the toner of the first color is collected in the original developing cartridge 15, the toners of the second, third, and fourth colors are similarly collected in the original developing cartridge 15. To be done.

After collecting the patches (S130), first, it is judged whether or not the density detected for the patch of the first color is the specified density (S140). If the detected density is not the specified density (S140: NO), the magnitude of the developing bias to be applied to the developing roller 18 for the first color is set to the density /
The change is made based on the developing bias conversion table 59b (S160). On the other hand, if the detected density of the patch of the first color is the specified density (S140: YES), the completion flag indicating that the calibration of the first color is completed is set (S150).

Then, regarding the second to fourth color patches,
Processing for the density of the patch of the first color (S140 to S1
60) is performed (“S170 to S190”,
"S200-220", "S230-S250"). In this way, when the processing concerning the densities of the patches of the first to fourth colors (S140 to S250) is completed, it is judged whether or not the calibration of all the colors is completed based on each completion flag (S260), and it is completed. In case, (S2
60: YES), the calibration process is ended, but if it is not completed (S260: NO), S
Return to 110. In S110, the patch of the color for which the completion flag is not set is developed, and S120-
Each processing of S260 is repeated.

In the color laser printer 1 of the present embodiment described above, the same effect as that of the first embodiment can be obtained, and the toner is discharged from the plurality of developing cartridges 15 while the photosensitive belt 22 makes one revolution. The operation is such that each is supplied to form a patch, so that the supply characteristics for each toner can be measured quickly.

Next, the third embodiment will be described. The color laser printer 1 according to the first embodiment described above includes the photosensitive belt 2
The calibration is performed by measuring the densities of the patches formed on the sheet 2. The color laser printer 301 of the third embodiment further measures the densities of the patches transferred from the photosensitive belt 22 onto the intermediate transfer belt 26. Then, the calibration is performed.

The density sensor 39 in the color laser printer 301 of this embodiment is arranged so that it can detect the optical density of the toner image formed on the intermediate transfer belt 26 as shown in FIG.
It is arranged in the vicinity of the intermediate transfer belt 26 as shown in FIG. Also, while performing the calibration described below,
The intermediate transfer belt cleaning roller drive unit 57 separates the intermediate transfer belt cleaning roller 38 from the intermediate transfer belt 26. With regard to the configuration and operation of the present embodiment other than those particularly described,
Since this is the same as the embodiment, the same reference numerals are given and the description is omitted.

Now, as shown in FIG. 8, in the calibration of the color laser printer 301 of this embodiment,
The development color setting is initialized as in S10 of the first embodiment (S310), and the patch is developed as in S20 (S320). That is, by applying a developing bias to the developing roller 18 in a state where the developing roller 18 of the developing cartridge 15 which stores the toner of the set color is in contact with the photosensitive belt 22 (FIG. 9: t1 to t8). (FIG. 9: t2 to t4), from the developing roller 18 to the photosensitive belt 22.
Then, the toner is moved to form a patch of the color set above (S320), and the patch formed on the photosensitive belt 22 is transferred to the intermediate transfer belt 26 side (S325). That is, the potential Vt of the intermediate transfer belt 26 is set to about −300 V by the primary transfer bias applying circuit 53 (FIG. 9: t3 to t5), and is lower than the potential of the area where the patch is formed on the photosensitive belt 22 (that is, about 200 V). By setting the potential to be low, at the contact position between the photosensitive belt 22 and the intermediate transfer belt 26,
The patch is transferred (primary transfer) from the photosensitive belt 22 to the intermediate transfer belt 26.

The density of the patch transferred to the intermediate transfer belt 26 is determined by the density sensor 39 when the patch faces the density sensor 39 due to the circular movement of the intermediate transfer belt 26.
Is detected (S330). After that, the patch reaches a position facing the transfer roller 13, but since the transfer roller 13 is moved to a position separated from the intermediate transfer belt 26 by the transfer roller driving unit 61 during calibration, the patch is moved from the intermediate transfer belt 26. The patch is not transferred to the transfer roller 13, and the patch is not transferred to the paper 3.

Then, the patch whose optical density is detected as described above is reversely transferred from the intermediate transfer belt 26 to the photosensitive belt 22 (S335). That is, the potential Vt of the intermediate transfer belt 26 is set to about 500 V by the primary transfer bias applying circuit 53 (FIG. 9: t5 to t7) and is set to a potential higher than the potential of the photosensitive belt 22 (about 0 V), so that a predetermined value is obtained. At the contact position, the patch is transferred from the intermediate transfer belt 26 to the photosensitive belt 22.

When the patch is transferred from the intermediate transfer belt 26 to the photosensitive belt 22 (S335), the toner used for forming the patch is collected in the original developing cartridge 15 (S340). Specifically, with the developing cartridge 15 kept in contact with the photosensitive belt 22, the voltage Vb to be applied to the developing roller 18 is set to about −100 V (FIG. 9: t6 to t9) and the potential of the photosensitive belt 22 (about By lowering the potential Vb of the developing roller 18 from 0 V, the toner is collected in the developing cartridge 15 (S34).
0).

For the processing after S340, refer to S in FIG.
Since it is similar to 50 to S80, the same step numbers are given and the description thereof is omitted. However, when the process of changing the developing bias (S60) and the process of changing the developing color (S80) are performed, the process returns to S320. Therefore, after the calibration operation for the first color is performed, as shown in FIG.
The calibration of the second color, the third color, and the fourth color will be performed in order.

In this embodiment, the intermediate transfer belt 26 corresponds to the "image carrier" in claim 1 and the like, and the photosensitive belt 22 corresponds to the "other image carrier" in claim 10. ,
The sheet 3 corresponds to the "transfer medium" in the claims. Also, C
The PU 51 and the transfer roller drive unit 61 function as the "restriction unit" in the claims, and the CPU 51, the primary transfer bias application circuit 53, the development bias application circuit 54, and the development cartridge drive unit 60 function as the "collection unit" in the claims. (S335, S340). Further, the intermediate transfer belt cleaning device 36 corresponds to the "cleaning means" in the claims, and the CPU 51 and the intermediate transfer belt cleaning roller driving unit 57 correspond to the "inhibition means" in the claims.
And the processes of S320 and S325 function as the "patch forming unit" in the claims.

As described above, in the color laser printer 301 of this embodiment, by separating the transfer roller 13 from the intermediate transfer belt 26, the toner for patch formation is transferred from the intermediate transfer belt 26 to the transfer roller 13 or the sheet 3. The transfer is regulated, and a bias is generated in the developing cartridge 15 in the direction in which the toner moves, and the developing roller 18 of the developing cartridge 15 is brought into contact with the photosensitive belt 22 to collect the toner in the original developing cartridge 15. To do. Therefore, the toner can be easily collected even when the calibration using the patch is performed, and as a result, the toner decrease can be suppressed. Further, since it is less necessary to remove the toner for forming the patch with the cleaning member, it is possible to suppress the deterioration of the cleaning member.

Also, the color laser printer 3 of this embodiment is used.
In No. 01, the developing cartridge 15 stores the non-magnetic one-component toner as the developer, and by the contact developing method,
Since this toner is supplied, the developing roller 18 of the developing cartridge 15 can be easily brought into contact with the photosensitive belt 22, and the toner can be easily collected.

Also, the color laser printer 3 of this embodiment is used.
In 01, from the intermediate transfer belt 26 to the transfer roller 1
The transfer roller 13 is separated from the intermediate transfer belt 26 in order to regulate the movement of the toner to the third and the like. Therefore, it is possible to reliably regulate the movement of the toner from the intermediate transfer belt 26 to the transfer roller 13 or the like.

The color laser printer 3 of this embodiment is also used.
In No. 01, the intermediate transfer belt cleaning device 36 for removing the toner remaining on the intermediate transfer belt 26 after the secondary transfer is provided, but during calibration (that is, from the intermediate transfer belt 26 to the transfer roller 1).
While the movement of the toner to 3 and the like is regulated), the toner is separated from the intermediate transfer belt 26 and the removal of the toner from the intermediate transfer belt 26 is prohibited. Therefore, the deterioration of the cleaning performance of the intermediate transfer belt cleaning device 36 is not accelerated and the toner is not prevented from being collected in the developing cartridge 15.

The color laser printer 3 of this embodiment is also used.
In No. 01, a plurality of developing cartridges 15 for supplying toners of different colors are provided, but toners supplied from any of the developing cartridges 15 and restricted from moving from the intermediate transfer belt 26 to the transfer roller 13 or the like are supplied. , Are recovered in the original developing cartridge 15. Therefore, it is possible to collect and reuse the toner while preventing the toners of different colors from being mixed with each other.

Also, the color laser printer 3 of this embodiment is used.
In No. 01, a patch is formed on the intermediate transfer belt 26, and its optical density is detected. Therefore, the toner supply characteristic can be measured in a form that reflects the transfer efficiency from the photosensitive belt 22 to the intermediate transfer belt 26.

Next, a fourth embodiment will be described. In the third embodiment described above, only one color patch is formed while the intermediate transfer belt 26 makes one revolution. In the fourth embodiment, a plurality of patches are formed while the intermediate transfer belt 26 makes one revolution. The patch of the color is formed on the intermediate transfer belt 26. The configuration and the operation of this embodiment are the same as those of the third embodiment except for the matters to be particularly described, and therefore, the same reference numerals are given and the description thereof will be omitted.

Now, as shown in FIGS. 10 and 11, in the calibration process of the color laser printer 301 of this embodiment, the photosensitive belt 22 makes one round of development of the patches of each color from the first color to the fourth color. While doing (S41
0). That is, first, the photosensitive belt 2 on which the electrostatic latent image is formed
The first color developing cartridge 15 is brought into contact with the surface of No. 2 (FIG. 11: t1 to t5), and a developing bias (about 500 V) is applied to the developing roller 18 (FIG. 11: t2 to t5).
t4) A patch of the first color is formed. Then, as shown in FIG. 11, while the photosensitive belt 22 makes one revolution,
The formation of patches for the fourth and fourth colors is performed in the same manner.

Next, the patch formed on the photosensitive belt 22 is transferred to the intermediate transfer belt 26 side (S415).
That is, the potential Vt of the intermediate transfer belt 26 is set to about -300 V by the primary transfer bias applying circuit 53 (FIG. 11:
t3 to t6), by setting the potential lower than the potential (that is, about 200 V) of the area where the patch is formed on the photosensitive belt 22, the intermediate position from the photosensitive belt 22 is reduced at the contact position between the photosensitive belt 22 and the intermediate transfer belt 26. The patch is transferred (primary transfer) to the transfer belt 26. And FIG.
As shown in, the second, third, and fourth color patches are transferred in the same manner.

The densities of the patches of the respective colors transferred to the intermediate transfer belt 26 are sequentially detected by the density sensor 39 when the patches face the density sensor 39 due to the circular movement of the intermediate transfer belt 26 (S420). The patches of each color whose optical density has been detected are reversely transferred from the intermediate transfer belt 26 to the photosensitive belt 22 (S425). That is, the potential Vt of the intermediate transfer belt 26 is set to about 500 V by the primary transfer bias applying circuit 53 (FIG. 11: t6 to t9),
By setting the potential higher than the potential of the photosensitive belt 22 (about 0 V), the patch of each color is transferred from the intermediate transfer belt 26 to the photosensitive belt 22 at a predetermined contact position.

When the patch is transferred from the intermediate transfer belt 26 to the photosensitive belt 22 (S425), the toner used for forming the patch is collected in the original developing cartridge 15 (S430). Specifically, the voltage Vb applied to the developing roller 18 is set to about −100 V (FIG. 11: t7 to t1).
1) With the potential Vb of the developing roller 18 lower than the potential of the photosensitive belt 22 (about 0 V), the developing cartridge 15 is brought into contact with the photosensitive belt 22 sequentially (FIG. 11: t8).
.About.t10), the toner is collected in the developing cartridge 15 (S430).

That is, the patches are sequentially transferred to the photosensitive belt 22 from the intermediate transfer belt 26 in reverse. The patches are transferred (primarily transferred) from the developing device to the intermediate transfer belt 26 in the order of color development on the photosensitive belt 22, and the photosensitive belt 22 is transferred in that order.
Is reverse transcribed into. This is because the rotational movement directions of the photosensitive belt 22 and the intermediate transfer belt 26 do not change between the primary transfer and the reverse transfer. Then, each developing cartridge 15
Is moved from the separated position to the developing position by the developing device contact / separation mechanism when the patch of the corresponding color arrives, and the developing roller 18
Are rotated in contact with the patches of the corresponding color on the photosensitive belt 22. At this time, the developer forming the patch is applied to the developing roller 18 with the bias adjusted from the photosensitive belt 22 toward the developing cartridge 15, so that the patch is collected in the developing cartridge 15.
When the collection of the patch is completed, the developing cartridge 15
Is moved from the developing position to the separating position by the developing device contacting / separating mechanism, and the developing cartridge 15 of the next color is moved from the separating position to the developing position. In this way, the developing cartridge 15 comes into contact with the patch forming portion of the corresponding color on the photosensitive belt 22, and is separated before the contact with the patch forming portion of another color after collecting the developer, so that the developing cartridge 15 of the corresponding color is separated. Only the developer is collected in the developing cartridge 15. By performing this operation in synchronization with the revolving movement of the photosensitive belt 22,
The formed patches of each color are sequentially collected in the developing cartridge 15 of the corresponding color.

For the processing after S430, refer to S in FIG.
Since it is the same as 140 to S260, the same step numbers are assigned and the description is omitted. However, in the process of S260, when it is determined that the calibration is not completed for all the colors (S260: NO), S4 is performed.
Return to 10.

In the color laser printer 301 of the present embodiment described above, the same effect as that of the third embodiment can be obtained, and the toner from the plurality of developing cartridges 15 can be removed while the intermediate transfer belt 26 makes one revolution. Since the toner is supplied to the intermediate transfer belt 26 to operate to form a patch on the intermediate transfer belt 26, the supply characteristics of each toner can be quickly measured.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can take various modes. For example, the first and second
In the embodiment, the potential of the intermediate transfer belt 26 is set to the photosensitive belt 2.
Although the potential of the toner from the photosensitive belt 22 to the intermediate transfer belt 26 is regulated by making the potential higher than the potential of the area where the second patch is formed, the invention is not limited to this. For example, it is conceivable that the movement of the toner from the photosensitive belt 22 to the intermediate transfer belt 26 is regulated by separating the intermediate transfer belt 26 and the photosensitive belt 22. With this configuration, it is possible to more reliably regulate the movement of the toner.

On the other hand, in the third and fourth embodiments,
By separating the transfer roller 13 and the intermediate transfer belt 26 from each other, the transfer of toner from the intermediate transfer belt 26 such as the transfer roller 13 is regulated, but the present invention is not limited to this. For example, it is possible to regulate the movement of toner by making the potential on the transfer roller 13 side higher than that on the intermediate transfer belt 26 side.

Further, although each of the embodiments is provided with a plurality of developing devices for forming a color image, it can also be applied to the case of monochrome (when there is one developing device). In that case, it is not necessary to provide a developing device contact / separation mechanism of the developing cartridge drive unit. Further, in the above-described embodiment, the color laser printer is described as an example of the image forming apparatus, but the image forming apparatus is not limited to this. For example, the present invention can be applied to a monochrome printer.

[Brief description of drawings]

FIG. 1 is a diagram showing a mechanical configuration of a color laser printer according to first and second embodiments.

FIG. 2 is a diagram showing an electrical configuration of a color laser printer.

FIG. 3 is a flowchart showing a calibration process performed in the color laser printer of the first embodiment.

FIG. 4 is a time chart showing the operation of the color laser printer of the first embodiment.

FIG. 5 is a flowchart showing a calibration process performed in the color laser printer of the second embodiment.

FIG. 6 is a time chart showing the operation of the color laser printer of the second embodiment.

FIG. 7 is a diagram showing a mechanical configuration of color laser printers according to third and fourth embodiments.

FIG. 8 is a flowchart showing a calibration process performed in the color laser printer of the third embodiment.

FIG. 9 is a time chart showing the operation of the color laser printer of the third embodiment.

FIG. 10 is a flowchart showing a calibration process performed in the color laser printer of the fourth embodiment.

FIG. 11 is a time chart showing the operation of the color laser printer of the fourth embodiment.

[Explanation of symbols]

1,301 ... Color laser printer 3 ... Paper 12 ... Intermediate transfer belt mechanism 13 ... Transfer roller 15 ... Development cartridge 16 ... Photosensitive belt mechanism section 17 ... Scorotron type charger 18 ... Developing roller 22 ... Photosensitive belt 26 ... Intermediate transfer belt 33 ... Photosensitive belt cleaning device 35 ... Photosensitive belt cleaning roller 36 ... Intermediate transfer belt cleaning device 38 ... Intermediate transfer belt cleaning roller 39 ... Concentration sensor 51 ... CPU 53 ... Primary transfer bias applying circuit 54 ... Development bias application circuit 55 ... Main drive 56 ... Photosensitive belt cleaning roller drive unit 57 ... Intermediate transfer belt cleaning roller drive unit 58 ... RAM, 59 ... ROM 59a ... Sensor output / concentration conversion table 59b ... Density / Development bias conversion table 60 ... Developing cartridge drive unit 61 ... Transfer roller driving unit

Continued front page    F term (reference) 2H027 DA10 DE02 DE07 DE10 EA18                       EB04 EB08 EC03 EC06 ED01                       ED08 ED24 ED27 EE07                 2H030 AA03 AD03 AD17 BB02 BB23                       BB34 BB42 BB46 BB53 BB54                 2H077 AA37 AC04 AC16 AD06 AD13                       AD35 DA03 DA47 DA62 EA14                       EA15 GA13                 2H134 GA01 GA06 GB02 HA01 HA11                       HA13 HA16 HA17 HB08 KA18                       KB03 KB07 KB14 KD07 KG03                       KG04 KG08 KH01 KJ02                 2H200 FA09 GA16 GA24 GA34 GA46                       GA47 GA52 GA56 GB15 GB25                       GB37 HA03 HA04 HA12 HB03                       HB12 HB22 JA02 JA28 JA29                       JA30 JC04 JC12 JC15 JC18                       LA14 LA24 LB02 LB03 LB15                       LB33 LB35 MA03 MA04 MA14                       MA20 NA02 PA10 PA19 PB13                       PB17 PB18 PB39

Claims (10)

[Claims] 1. An image forming apparatus for forming an image by transferring a developer image formed on an image carrier by a developer supplied from a developing device to a transfer medium, the image carrier comprising: A regulating unit that regulates the movement of the developer to the transfer medium, and a developer whose movement from the image carrier to the transfer medium is regulated by the regulating unit is collected from the image carrier to the developing device. An image forming apparatus comprising: a collecting unit. 2. The collecting means collects the developer in the developing device by generating a bias in a direction in which the developer moves in the developing device.
The image forming apparatus according to item 1. 3. The developing device is non-magnetic as the developer.
3. The image forming apparatus according to claim 1, wherein the component toner is stored and the developer is supplied by a contact development method. 4. The regulating means regulates the movement of the developer from the image carrier to the transfer medium by generating a bias in a direction in which the developer moves from the transfer medium to the image carrier. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. 5. The regulating means regulates the movement of the developer from the image carrier to the transfer medium by separating the transfer medium and the image carrier from each other. The image forming apparatus according to any one of 4 to 4. 6. A cleaning unit for removing, from the image carrier, the developer remaining on the image carrier after transferring the developer image formed on the image carrier to a transfer medium, And a prohibiting means for prohibiting the cleaning means from removing the developer from the image carrier when the restricting means restricts the movement of the developer from the image carrier to the transfer medium. The image forming apparatus according to any one of claims 1 to 5, wherein: 7. A patch forming means for forming a patch for measuring a supply characteristic of a developer on the image carrier, wherein the regulating means is supplied from the developing device to form the patch. The developing agent is regulated from moving from the image carrier to the transfer medium, and the collecting means removes the developer supplied from the developing device to form the patch from the image carrier. The image forming apparatus according to claim 1, wherein the image forming apparatus collects the image in a developing device. 8. A plurality of developing devices for supplying developers of different colors are provided as the developing devices, and the collecting means is supplied from any of the developing devices, and the regulating means supplies the image carrier to the developing device. The image forming apparatus according to claim 7, wherein the developer whose movement to the transfer medium is restricted is collected in the supplied developing device. 9. The patch forming means includes the image carrier 1
Supplying the developer from each of the developing units during the cycle,
The image forming apparatus according to claim 8, wherein a patch for measuring the supply characteristic of each developer is formed. 10. The image carrying member carries a developer image by transferring a developer image formed on another image carrying member, and the collecting means is provided by the regulating means. The developer whose movement from the image carrier to the transfer medium is regulated is collected via the other image carrier.
9. The image forming apparatus according to any one of 9.