JP2003029588A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform cleaning operation only when an image forming time is not influenced by the lowering of the electrification of residual toner by appropriately setting a cleaning operation starting condition. SOLUTION: This image forming device is equipped with a fixing device temperature sensor SN2 detecting the temperature of a fixing device F for fixing a toner image transferred to a recording sheet S, and a cleaning work control means having a cleaning work performing means for performing cleaning work that toner attracted and held on toner attracting and holding members CLp and CLy to CLk is recovered by cleaners CLb and CL3, a cleaning work starting means for starting the cleaning work according to a detected temperature signal from the sensor SN2, and a cleaning work finishing means for finishing the cleaning work in set timing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a primary toner image carrier on which a toner image is formed on a rotating surface, an intermediate toner image carrier on which the toner image is intermediately transferred, and the intermediate toner image carrier. And an image forming apparatus provided with a sheet transfer device for transferring the toner image on the surface of the recording sheet to a recording sheet. The present invention relates to an image forming apparatus provided with a toner suction holding member that discharges the toner that is temporarily sucked and held at the timing, and a toner collecting cleaner that collects the discharged toner. The present invention can be applied to image forming apparatuses such as electrophotographic copying machines, laser beam printers, and electrostatic recording devices. Further, the present invention is particularly preferably applicable to an image forming apparatus having a plurality of primary toner image carriers.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic copying machine, a laser beam printer, and a facsimile, when forming a color image, a plurality of primary toner image bearing members (Y ( Yellow), M (magenta), C (cyan), and K (black) primary toner image carriers), and the toner images of the respective colors formed on the plurality of primary toner image carriers are intermediate toner image carriers. 2. Description of the Related Art There is conventionally known an image forming apparatus of a type in which a toner image on the surface of the intermediate toner image carrier is transferred onto a recording sheet by superposing and transferring the image onto an intermediate transfer belt, an intermediate transfer drum, or the like.
When a plurality of such primary toner image bearing members (photoconductors) are used, a plurality of respective primary toner image bearing members (photoconductors) and the intermediate toner image bearing members (intermediate transfer belt or intermediate transfer drum, etc.) are used. If a cleaner that cleans the residual toner on the surface of each of the intermediate transfer members) is provided, the number of cleaners increases, which makes it difficult to downsize the image forming apparatus and reduce the manufacturing cost. It was

The following techniques (J01) and (J02) are conventionally known as methods for solving the above-mentioned problems. (J01) Japanese Patent Application Laid-Open No. 11-249452 In this publication, a toner holding means for temporarily adsorbing and holding the residual toner remaining on the image carrier after the transfer is provided, and the adsorbing means holds the toner from the toner holding means at a predetermined timing. A technique is disclosed in which the held toner is discharged and collected by a cleaner provided on an intermediate toner image carrier (intermediate transfer member).

[0004]

(Problems to be Solved by the Invention)
Problem 1) In the prior art (J01), when the image formation is not performed for a long time, the residual toner temporarily held by the toner holding unit is charged less. If you start image formation when the residual toner charge is low,
The residual toner cannot be retained by the toner retaining unit, and the residual toner is discharged from the toner retaining unit to the image carrier, which may lead to deterioration of image quality. Prior art (J01)
Does not have a criterion for determining the start timing of the discharged toner collection (hereinafter referred to as cleaning). Therefore, in the case where the cleaning is configured to be performed before the start of image formation, the cleaning is performed even when the cleaning is not necessary, so that the time until the image formation becomes long, the productivity is lowered, and it is inconvenient for the user. . If a device for measuring the period during which image formation is not performed is provided in order to perform cleaning only when image formation is not performed for a long time, that is, when the residual toner charge is reduced, the power supply The period cannot be measured when it is off. In addition, if a battery is used in a device that measures the period during which the image formation is not performed in order to cope with power-off, the cost will increase.

In view of the above circumstances (and the results of the study), the present invention includes a primary toner image carrier (photoconductor) and an intermediate toner image carrier (intermediate transfer belt, intermediate transfer drum, or other intermediate transfer member). A cleaner is provided in one of the toner image bearing members, and a toner attracting / holding member that temporarily attracts and holds the toner to the other toner image bearing members and discharges the attracted and held toner at a predetermined timing. In an image forming apparatus that collects the discharged toner in the cleaner, the content described in (O01) below is an object. (O01) By properly setting the start condition of the cleaning operation,
Perform the cleaning operation only when the residual toner charge is reduced and does not affect the image formation time.

[0006]

The present invention devised to solve the above problems will now be described. The elements of the present invention are to facilitate correspondence with the elements of the embodiments described later. Note that the reference numerals of the elements of the embodiments are enclosed in parentheses. The reason why the present invention is described in association with the reference numerals of the embodiments described later is to facilitate the understanding of the present invention and not to limit the scope of the present invention to the embodiments. (Invention) In order to solve the above problems, an image forming apparatus of the present invention is characterized by having the following constituent requirements (A01) to (A010). (A01) A primary toner image carrier (PR, Py, ...) having a toner image formed on its surface and carrying the formed toner image.
Pk) and the primary toner image carrier (PR, Py to Pk)
A plurality of toner image carriers (P, B1 to B3) to which the toner image on the surface of the toner image is transferred.
R, B; Py to Pk, B; Py to Pk, B1 to B3),
(A02) A sheet transfer device (T) for transferring the toner image on the intermediate toner image carrier (B, B3) to the recording sheet (S).
2), (A03) a cleaner (CLb, CL3) disposed adjacent to the surface of the intermediate toner image carrier (B, B3) for collecting the toner adhering to the surface into a toner recovery container,
(A04) The primary toner image carrier (PR, Py to Pk)
A toner adsorbing / holding member (CL) that is disposed adjacent to the surface of the
p, CLy to CLk), (A05) Each toner image carrier (PR, B; Py to Pk, B; Py to Pk, B1, B)
2) transfer bias control means (C1) for applying a transfer bias for transferring the toner between (A06), the toner on the surface of the primary toner image carrier (PR, Py to Pk), and the toner adsorption holding member (CLp). , CLy to CLk), and an adsorption bias applying means (C3A) for applying an adsorption transfer bias for transferring to the toner adsorption holding member (CL).
p, CLy to CLk), the toner adsorbed and held by
Reverse transfer bias applying means (C) for applying a reverse transfer bias for reverse transfer to the next toner image carrier (PR, Py to Pk)
3B), toner adsorption transfer control means (C3), (A
07) Cleaner bias control means (C) for applying a cleaning bias for collecting the toner on the surface of the intermediate toner image carrier (B, B3) to the cleaner (CLb, CL3).
4), (A08) Sheet transfer device bias control means for applying a sheet transfer bias for transferring the toner image on the intermediate toner image carrier (B, B3) to the recording sheet (S) to the sheet transfer device (T2). (C2), (A09) Fixing device temperature sensor (SN2) for detecting the temperature of the fixing device (F) for fixing the toner image transferred onto the recording sheet (S),
(A010) The toner adsorption holding member (CLp, CLy to
The toner adsorbed and held by CLk) is applied to the reverse transfer bias applying means (C3) of the toner adsorption transfer control means (C3).
B) the primary toner image carrier (PR, Py to P)
k) and the primary toner image carrier (PR,
Py to Pk) toner on the surface is transferred to the intermediate toner image carrier (B, B1 to B3) by the transfer bias control means (C1).
To the intermediate toner image carrier (B, B1 to B).
3) Cleaning work executing means (C6B) for executing the cleaning operation for collecting the toner on the surface by the cleaner bias control means (C4) to the cleaners (CLb, CL3), and the fixing device temperature sensor (SN2).
Cleaning work control means (C6) having a cleaning work starting means (C6A) for starting the cleaning work in response to the detected temperature signal of No. 6 and a cleaning work ending means (C6C) for ending the cleaning work at a set timing. .

(Operation of the Present Invention) In the image forming apparatus of the present invention having the above construction, the toner adsorption / transfer control means (C3)
Is the primary toner image carrier (PR, Py) by the transfer bias for adsorption applied by the adsorption bias applying means (C3A).
To Pk) toner on the surface of the toner adsorption holding member (CL
p, CLy to CLk) and the toner transfer holding members (CLp, CLy to CL) by the reverse transfer bias applied by the reverse transfer bias applying means (C3B).
The toner that is temporarily adsorbed and held by k) is reversely transferred to the primary toner image carrier (PR, Py to Pk). The transfer bias control means (C1) is provided for each toner image carrier (P
A transfer bias is applied between R, B; Py to Pk, B; Py to Pk, B1 to B3) to transfer the toner. The cleaner bias control means (C4) applies the cleaning bias to the intermediate toner image carrier (B, B1 to B1).
B3) The toner adhered to the surface is cleaned by the cleaner (CLb,
CL3) collects the toner in a toner collecting container. The sheet transfer device bias control means (C2) applies a sheet transfer bias to the sheet transfer device (T2) to record the toner image on the intermediate toner image carrier (B, B1 to B3) on the recording sheet (S). Transfer to. The fixing device temperature sensor (SN2) detects the temperature of the fixing device (F) that fixes the toner image transferred to the recording sheet (S). Cleaning work starting means (C6) of the cleaning work control means (C6)
A) starts the cleaning operation in response to the temperature signal detected by the fixing device temperature sensor (SN2). The cleaning operation executing means (C6B) uses the reverse transfer bias applying means (C3B) of the toner adsorption / transfer control means (C3) to set the toner adsorbed and held by the toner adsorption / holding members (CLp, CLy to CLk) to 1 The toner on the surface of the primary toner image carrier (PR, Py to Pk) is reversely transferred to the next toner image carrier (PR, Py to Pk) and is transferred to the intermediate toner image carrier (C1) by the transfer bias control means (C1). B, B1 to B3) to move the toner on the surface of the intermediate toner image carrier (B, B1 to B3) to the cleaner (CL) by the cleaner bias control means (C4).
b, CL3). The cleaning operation ending means (C6C) ends the cleaning operation at the set timing. Therefore, depending on the result of the temperature detected by the fixing device temperature sensor (SN2), if the image formation is not performed for a long time and the charge of the residual toner decreases, or
Since the cleaning work is started after judging the case where the time for image formation is not affected, it is possible to prevent the deterioration of the image forming work efficiency (productivity).

Further, the image forming apparatus of the present invention has the above-mentioned constituent elements (A01) to (A09) and the following constituent elements (A011), (A0).
It is characterized by having 12). (A011) Environmental temperature sensor (SN3) for detecting the temperature inside the image forming apparatus, (A012) The toner adsorption / transfer control means (C3) for the toner adsorbed and held by the toner adsorption / holding members (CLp, CLy to CLk). The reverse transfer bias applying means (C3B) reversely transfers the toner to the primary toner image carrier (PR, Py to Pk) and transfers the toner on the surface of the primary toner image carrier (PR, Py to Pk). The bias control unit (C1) moves the intermediate toner image carrier (B, B1 to B3) to remove the toner on the surface of the intermediate toner image carrier (B, B1 to B3) from the cleaner bias control unit (C4). The cleaner (CL
b, CL3) cleaning work execution means (C6B) for executing the cleaning work to be collected, and the cleaning in accordance with the temperature signal detected by the fixing device temperature sensor (SN2) and the temperature signal detected by the environmental temperature sensor (SN3). Cleaning work starting means (C6) for starting work
Cleaning work control means (C6) having A) and cleaning work end means (C6C) for ending the cleaning work at a set timing.

In the image forming apparatus of the present invention having the above structure, the ambient temperature sensor (SN3) detects the temperature inside the image forming apparatus. The processes of the cleaning work control means (C6) and the cleaning work execution means (C6B) are as described above. Therefore, the detected temperature of the fixing device temperature sensor (SN2) and the environmental temperature sensor (S
According to the result of the detected temperature of N3), the cleaning operation is started by determining whether the image formation is not performed for a long time and the charge of the residual toner is reduced, or when the image formation time is not affected. It is possible to prevent a decrease in work efficiency (productivity).

An image forming apparatus of the present invention having the above-mentioned configurations (A01) to (A010) or (A01) to (A09), (A011), (A012) has the following configurations (A013) to (A01).
6) can be provided. (A013) The intermediate toner image carrier (B, B1 to B3)
The sheet transfer device (T2) having a sheet transfer roll (T2b) for transferring the toner image on the recording sheet (S),
(A014) A toner adsorbing / holding member (CLt) for a transfer roll, which is disposed adjacent to the surface of the sheet transfer roll (T2b) and temporarily adsorbs and holds the toner attached to the surface of the sheet transfer roll (T2b), (A015) Adsorption bias applying means (C5A) for applying an adsorption transfer bias for transferring the toner on the surface of the sheet transfer roll (T2b) to the toner adsorption holding member (CLt), and the toner adsorption holding member (CLt). Reverse transfer bias applying means (C5) for applying a reverse transfer bias for reversely transferring the toner adsorbed and held on the sheet transfer roll (T2b).
Toner adsorption transfer control means (C) for a transfer roll having B)
5), (A016) The toner attracted and held by the toner attracting and holding member (CLt) by the reverse transfer bias applying means (C5B) of the transfer roll toner transfer control means (C5) is transferred to the sheet transfer roll (T2b). The toner on the surface of the sheet transfer roll (T2b) is reversely transferred and moved by the sheet transfer device bias control means (C2) to the intermediate toner image carrier (B, B1 to B3), and the cleaner bias control means ( The cleaning operation executing means (C6B) for executing the cleaning operation for collecting the toner on the surface of the intermediate toner image carrier (B, B1 to B3) by the cleaner (CLb, CL3) by C4).
A cleaning work starting means (C6A) for starting the cleaning work in response to a temperature signal detected by the fixing device temperature sensor (SN2), and a cleaning work ending means (C6C) for ending the cleaning work at a set timing. Cleaning operation control means (C
6).

In the image forming apparatus of the present invention having the above-mentioned structural requirements (A013) to (A016), the sheet transfer device (T
2) is composed of a sheet transfer roll (T2b), and the transfer roll toner adsorption holding member (CL) is disposed adjacent to the surface of the sheet transfer roll (T2b).
In t), the toner attached to the surface of the sheet transfer roll (T2b) is temporarily adsorbed and held. The suction bias applying means (C5A) of the transfer roll toner suction transfer control means (C5) applies a suction transfer bias to transfer the toner on the surface of the sheet transfer roll (T2b) to the toner suction holding member (C5A). The reverse transfer bias applying means (C5B) applies a reverse transfer bias to transfer the toner attracted and held by the toner attracting and holding member (CLt) to the sheet transfer roll (T2b).
The cleaning work starting means (C6A) of the cleaning work control means (C6) is the fixing device temperature sensor (SN).
The cleaning work is started according to the detected temperature signal of 2). The cleaning operation executing means (C6B) uses the sheet transfer roll (T2b) to hold the toner attracted and held by the toner attracting and holding member by the reverse transfer bias applying means (C5B) of the transfer roll toner adsorption and transfer control means (C5). To the sheet transfer roll (T2) by the sheet transfer device bias control means (C2).
b) The toner on the surface is transferred to the intermediate toner image carrier (B, B1).
To B3), the cleaner bias control means (C4) causes the intermediate toner image carrier (B,
The toner on the surface of B1 to B3) is cleaned by the cleaner (CLb,
CL3) collects. Cleaning work ending means (C
6C) ends the cleaning operation at the set timing.

Further, the image forming apparatus of the present invention having the above constitutions (A01) to (A010) or (A01) to (A09), (A011), (A012) has the constitutions (A013) to (A01).
5) and the following configuration (A016 ′) can be provided. (A016 ′) The toner transfer control means for the transfer roll (C
5) Reverse transfer of the toner attracted and held by the toner suction holding member (CLt) by the reverse transfer bias applying means (C5B) to the sheet transfer roll (T2b) and by the sheet transfer device bias control means (C2). The toner on the surface of the sheet transfer roll (T2b) is moved to the intermediate toner image carrier (B, B1 to B3), and the cleaner bias control means (C4) controls the intermediate toner image carrier (B, B1 to B3). ) The cleaning work executing means (C6B) for executing the cleaning work for collecting the toner on the surface of the cleaner (CLb, CL3), the temperature signal detected by the fixing device temperature sensor (SN2) and the environmental temperature sensor (SN3). ) Cleaning work starting means (C6A) for starting the cleaning work according to the detected temperature signal of Cleaning operation ending means for ending the cleaning operation at a constant timing (C6
Cleaning work control means (C6) having C).

The above constituent elements (A013) to (A015), (A
In the image forming apparatus of the present invention equipped with 016 '), the cleaning operation starting means (C6A) of the cleaning operation control means (C6) detects the temperature signal of the fixing device temperature sensor (SN2) and the environmental temperature sensor (SN3). The cleaning operation is started in response to the detected temperature signal of (1). The processing by the cleaning work executing means (C6B) and the cleaning work ending means (C6C) is as described above.

An image forming apparatus of the present invention having the above-mentioned configurations (A01) to (A010) or (A01) to (A09), (A011), (A012) has the following configurations (A017), (A01).
8) can be provided. (A017) A plurality of primary toner image carriers (PR, Py to Pk) on which toner images of different colors are formed, (A018)
A plurality of primary intermediate toner image carriers (B, B1) to which toner images are transferred from the plurality of primary toner image carriers (Py to Pk).
To B3), the primary intermediate toner image carrier (B, B1) in which the toner adsorption holding member is arranged adjacent to the surface.
To B3) and the plurality of primary intermediate toner image bearing members (B
The toner image on the surface of (1, B2) is secondarily transferred.
The second intermediate toner image carrier (B3), wherein the cleaners (CLb, CL3) are arranged adjacent to the surface.
The intermediate toner image carrier (B1 to B3) having the next intermediate toner image carrier (B3).

In the present invention having the above-mentioned structural requirements (A017) and (A018), a plurality of the primary toner image bearing members (Py to
Toner images of different colors are formed on Pk). Intermediate toner image carrier (B1 to B3) primary intermediate toner image carrier (B
1, B2) are the plurality of primary toner image carriers (Py to
The toner image is transferred from Pk). The toner adhering to the surface of the primary intermediate toner image carrier (B1, B2) is adsorbed and held by the toner adsorbing and holding members (CL1, CL2) arranged adjacent to the surface thereof. A secondary intermediate toner image carrier (B3) to which the toner images on the surfaces of the plurality of primary intermediate toner image carriers (B1, B2) are secondarily transferred.
Is a cleaner (CL3) placed adjacent to its surface
Thus, the toner adsorbed on the surface is collected.

The image forming apparatus of the present invention has the following constituent elements (A01), (A02 ') to (A04'), (A05), (A05).
06 ')-(A08'), (A09), (A010 '). (A01) A primary toner image carrier (PR, Py, ...) having a toner image formed on its surface and carrying the formed toner image.
Pk) and the primary toner image carrier (PR, Py to Pk)
A plurality of toner image carriers (P, B1, B2) to which the toner image on the surface of the toner image is transferred.
R, B; Py to Pk, B; Py to Pk, B1 to B3),
(A02 ') a sheet transfer roll (T2b) for transferring the toner image on the intermediate toner image carrier (B, B3) to the recording sheet (S), (A03') the sheet transfer roll (T2)
A cleaner (CLb, CL) disposed adjacent to the surface of b) for collecting the toner adhering to the surface into a toner recovery container
3), (A04 ′) The plurality of toner image bearing members (PR,
B; Py to Pk, B; Py to Pk, B1 to B3), which are arranged adjacent to the surface of the toner image carrier and temporarily adsorb and retain the toner adhering to the surface of the toner image carrier (CLp, CLy to CLk, CL1, CL2), (A0
5) Each of the toner image bearing members (PR, B; Py to Pk,
B; transfer bias control means (C) for applying a transfer bias for transferring toner between Py to Pk, B1, B2)
1), (A06 ') Each of the plurality of toner image carriers (PR,
B; Py to Pk, B; Py to Pk, B1 to B3), the toner on the surface of the toner adsorption holding member (CLp, CLy to
CLk, CL1, CL2) and a biasing means for applying attraction (C3A) for applying a transfer bias for attraction for transferring to CLk, CL1, CL2, and the toner suction holding members (CLp, CLy to CLk,
The toners adsorbed and held by CL1 and CL2 are respectively attached to the toner image carriers (PR, B; Py to Pk, B; Py to Pk,
B1 to B3) has a reverse transfer bias applying means (C3B) for applying a reverse transfer bias for reverse transfer to toner adsorption transfer control means (C3), (A07 '), and the toner on the surface of the sheet transfer roll (T2b) is cleaned by the cleaner. (CLb, C
Cleaner bias control means (C4) for applying a cleaning bias for collection to L3), (A08 ') a sheet transfer bias for transferring the toner image on the intermediate toner image carrier (B, B3) to the recording sheet (S). Sheet transfer device bias control means (C2) for applying to the sheet transfer roll (T2b), (A09) Fixing for detecting the temperature of a fixing device (F) for fixing the toner image transferred to the recording sheet (S) Container temperature sensor (SN2), (A010 ') the toner adsorption holding member (CLp, CLy to CLk, CL)
1, CL2) to the toner image carrier (PR, B; Py) by the reverse transfer bias applying means (C3B) of the toner adsorption transfer control means (C3).
~ Pk, B; Py ~ Pk, B1 ~ B3),
The primary toner image carrier (PR, B; Py to Pk, B;
The toner on the surface of Py to Pk, B1 to B3) is transferred to the intermediate toner image carrier (B, B) by the transfer bias control means (C1).
3), and the toner on the surface of the intermediate toner image bearing member (B, B3) is applied to the transfer roll bias applying means (C2).
To the sheet transfer roll (T2b) by
The cleaner bias control means (C4) cleans the toner on the surface of the sheet transfer roll (T2b) into a cleaner (CL).
The cleaning work executing means (C6B) for executing the cleaning work to be collected in t) and the cleaning work starting means (C6A) for starting the cleaning work in response to the detection signal of the fixing device temperature sensor (SN2) are set. Cleaning work control means (C6) having a cleaning work ending means (C6C) for ending the cleaning work at different timings.

The above structural requirements (A01), (A02 ') to (A02)
04 '), (A05), (A06') to (A08 '), (A0
In the image forming apparatus of the present invention including 9) and (A010 ′),
The toner adsorption / transfer control means (C3) uses the adsorption transfer bias applied by the adsorption bias applying means (C3A) to apply a plurality of toner image carriers (PR, B; Py to Pk, B;
The toner on the surface of Py to Pk, B1 to B3) is attached to the toner adsorption holding member (CLp, CLy to CLk, CL1, CL).
2) and the toner adsorption holding members (CLp, CLy to CLk, CL1, CL) by the reverse transfer bias applied by the reverse transfer bias applying means (C3B).
2) The toner temporarily adsorbed and held by the toner image carrier (PR, B; Py to Pk, B; Py to Pk, B1)
~ B3) reversely transferred. Transfer bias control means (C
1) is the toner image carrier (PR, B; Py to P)
k, B; Py to Pk, B1 to B3), a toner image transfer bias is applied to transfer the toner. The cleaner bias control means (C4) collects the toner on the surface of the sheet transfer roll (T2b) in the cleaner (CLt) by applying a cleaning bias. The sheet transfer device bias control means (C2) applies a sheet transfer bias to the sheet transfer roll (T2b) to transfer the toner image on the intermediate toner image carrier (B, B3) to the recording sheet (S). To do. The fixing device temperature sensor (SN2) detects the temperature of the fixing device (F) that fixes the toner image transferred to the recording sheet (S).

The cleaning work starting means (C6A) of the cleaning work control means (C6) starts the cleaning work in response to the temperature signal detected by the fixing device temperature sensor (SN2). Cleaning work execution means (C6B)
Does the following: (1) The toner suction holding member (CLp, CLy to CL)
The toners adsorbed and held on the toner image carrier (PR, CL, CL2) are applied to the toner image carrier (PR,
B; Py to Pk, B; Py to Pk, B1 to B3). (2) The primary toner image carrier (PR, B; Py to P)
k, B; Py to Pk, B1 to B3) surface toner is moved to the intermediate toner image carrier (B, B3) by the transfer bias control means (C1) and the intermediate toner image carrier (B, B3) is moved.
The toner on the surface of B3) is moved to the sheet transfer roll (T2b) by the transfer roll bias applying means (C2). (3) The cleaner bias control means (C4) causes the cleaner (CLt) to collect the toner on the surface of the sheet transfer roll (T2b). The cleaning operation ending means (C6C) of the cleaning operation control means (C6) ends the cleaning operation at the set timing. Therefore, depending on the result of the temperature detected by the fixing device temperature sensor (SN2), it is determined whether the image formation is not performed for a long time and the charge of the residual toner is lowered, or the case where the image formation time is not affected is determined. Since the work is started, it is possible to prevent a decrease in image forming work efficiency (productivity).

Further, the image forming apparatus of the present invention has the above-mentioned constituent elements (A01), (A02 ') to (A04'), (A05), (A).
06 ')-(A08'), (A09) and the following constituent requirements (A01
1) and (A012 ') are provided. (A011) Environmental temperature sensor (SN3) for detecting the temperature inside the image forming apparatus, (A012 ') The toner adsorbed and held on the toner adsorbing / holding members (CLp, CLy to CLk, CL1, CL2) is transferred to the toner adsorbing / transferring member. Control means (C
3) The toner image carrier (PR, B; Py to Pk, B; Py to) by the reverse transfer bias applying means (C3B).
Pk, B1 to B3), and the primary toner image carrier (PR, B; Py to Pk, B; Py to Pk, B1 to
The toner on the surface of B3) is transferred to the bias control means (C1).
To the intermediate toner image carrier (B, B3) and the toner on the surface of the intermediate toner image carrier (B, B3) is moved to the sheet transfer roll (T2b) by the transfer roll bias applying means (C2). Then, the cleaner bias control means (C4) controls the sheet transfer roll (T2).
b) Cleaning work executing means (C6B) for executing a cleaning work for collecting the toner on the surface to the cleaner (CLt), a temperature signal detected by the fixing device temperature sensor (SN2) and a temperature detected by the environment temperature sensor (SN3). A cleaning work control means (C6) having a cleaning work starting means (C6A) for starting the cleaning work in response to a signal and a cleaning work ending means (C6C) for ending the cleaning work at a set timing.

The above structural requirements (A01), (A02 ') to (A)
04 '), (A05), (A06') to (A08 '), (A0
In the image forming apparatus of the present invention including 9) and (A010 ′),
The fixing device temperature sensor (SN2) is the recording sheet (S).
The temperature of the fixing device (F) that fixes the toner image transferred to the printer is detected. The environmental temperature sensor (SN3) detects the temperature inside the image forming apparatus. The processes of the cleaning work starting means (C6A) and the cleaning work ending means (C6C) of the cleaning work control means (C6) are as described above. Therefore, depending on the result of the temperature detected by the fixing device temperature sensor (SN2), if the image formation is not performed for a long time and the charge of the residual toner decreases, or
Since the cleaning work is started after judging the case where the time for image formation is not affected, it is possible to prevent the deterioration of the image forming work efficiency (productivity).

The image forming apparatus of the present invention has the following constituent elements (A01 '), (A02), (A03 "), (A04"),
(A05), (A06 ″), (A07 ″), (A08), (A0
9) and (A010 ″) are provided. (A01 ′) A plurality of primary toner image carriers (P1) having a toner image formed on the surface thereof and carrying the formed toner image.
R, Py to Pk) and the primary toner image carrier (PR, Pk)
y to Pk) and a plurality of toner image carriers (PR, B; Py to Pk, B; Py to Pk, B1) including an intermediate toner image carrier (B, B1 to B3) to which the toner image on the surface is transferred. ~ B
3), (A02) a sheet transfer device (T2) for transferring the toner image on the intermediate toner image carrier (B, B3) to a recording sheet (S), (A03 ″) the plurality of toner image carriers (P2)
R, B; Py to Pk, B; Py to Pk, B1 to B3), and a cleaner (CLb, CL3) is disposed adjacent to the surface of the toner image carrier and adheres to the surface. The toners carried by the cleaner (CLb, CL3) are collected in the toner collecting container by the cleaners (B, B3), (A04 ″) The toner images other than the cleaner-carrying toner image carrier (B, B3) Carrier (PR, P
y to Pk, B1, B2) for temporarily adsorbing and holding the toner adhering to the surface thereof (CL)
p, CLy to CLk, CL1, CL2) are arranged adjacent to the surface of the toner image carrier (PR, Py) with a holding member.
To Pk, B1, B2), (A05) each of the toner image bearing members (PR, B; Py to Pk, B; Py to Pk, B1, B)
2) Transfer bias control means (C1) for applying a transfer bias for transferring toner between (A06 ″) and the toner image carrier (PR, Py to Pk, B1, B2) with the holding member.
The toner on the surface of the toner adsorption holding member (CLp, C
Adsorption bias applying means (C3) for applying an adsorption transfer bias for transferring to Ly to CLk, CL1, CL2)
A) and the toner adsorption / holding member (CLp, CLy to
The toners adsorbed and held on CLk, CL1, CL2) are held by the toner image carrier (PR, Py to Pk, B) with the holding member.
1, B2) has a reverse transfer bias applying means (C3B) for applying a reverse transfer bias for reverse transfer, and toner adsorption transfer control means (C3), (A07 ″) surface of the toner image carrier with cleaner (B, B3) Cleaner bias control means (C4), (A08) for applying a cleaning bias for collecting the toner of No. 2 to the cleaners (CLb, CL3)
Sheet transfer device bias control means (C2) for applying a sheet transfer bias for transferring the toner image on the intermediate toner image carrier (B, B3) to the recording sheet (S) to the sheet transfer device (T2), (A09). ) Fixing device temperature sensor (SN2) for detecting the temperature of the fixing device (F) for fixing the toner image transferred to the recording sheet (S), (A010 ″) the toner adsorption holding members (CLp, CLy to CLk) , CL
1, CL2) is held by the toner image carrier (P) with the holding member by the reverse transfer bias applying means (C3B) of the toner adsorption transfer control means (C3).
R, Py to Pk, B1, B2) and the toner image carrier with the holding member (PR, Py to Pk, B1, B1).
B2) The toner on the surface is transferred to the transfer bias control means (C
1) is moved to the toner image carrier with cleaner (B, B3), and the toner image carrier with cleaner (B, B3) is moved.
3) The toner on the surface is transferred to the cleaner bias control means (C
4) cleaning work execution means (C6B) for executing the cleaning work to be collected by the cleaners (CLb, CL3), and cleaning work for starting the cleaning work according to the temperature signal detected by the fixing device temperature sensor (SN2). A cleaning work control means (C6) having a starting means (C6A) and a cleaning work ending means (C6C) for ending the cleaning work at a set timing.

The above constituent elements (A01 '), (A02), (A
03 ″), (A04 ″), (A05), (A06 ″), (A0
7 ″), (A08), (A09), and (A010 ″), the image forming apparatus of the present invention includes a plurality of toner image carriers (PR,
B; Py to Pk, B; Py to Pk, B1 to B3), and a toner image carrier with a cleaner in which a cleaner (CLb, CL3) is disposed adjacent to the surface thereof. (B, B3) is the cleaner (CLb, CL) to which the toner attached to the surface is applied with a cleaning bias by the cleaner bias control means (C4).
By 3), the toner is collected in the toner collecting container. A toner image carrier (PR, Py to Pk, B1, B2) other than the toner image carrier with cleaner (B, B3) and a toner adsorption holding member (CLp, CLy to CLk, CL1, CL).
In the toner image carrier (PR, Py to Pk, B1, B2) with the holding member 2) arranged adjacent to the surface, the toner adhering to the surface of the toner image carrier (CLp, CLp,
CLy to CLk, CL1, CL2) are temporarily adsorbed and held.

The attracting bias applying means (C3A) of the toner attracting and transferring control means (C3) applies the attracting transferring bias to the toner image carrier (PR, Py.
The toner on the surface of Pk, B1, B2) is transferred to the toner adsorption holding member (CLp, CLy to CLk, CL1, CL2), and the reverse transfer bias applying means (C3B) is transferred to the toner adsorption holding member (CLp, CLy to CLk). CLk, CL1,
The toner adsorbed and held by CL2) is reversely transferred to the toner image carrier (PR, Py to Pk, B1, B2) with the holding member. The transfer bias control means (C1) includes the toner image bearing members (PR, B; Py to Pk, B; Py to Pk,
A transfer bias is applied between B1 to B3) to transfer the toner.

Sheet transfer device bias control means (C2)
Applies a sheet transfer bias to the sheet transfer device (T2) to transfer the toner image on the intermediate toner image carrier (B, B3) to the recording sheet (S). The fixing device temperature sensor (SN2) detects the temperature of the fixing device (F) that fixes the toner image transferred to the recording sheet (S).
The cleaning work starting means (C6A) of the cleaning work control means (C6) is the fixing device temperature sensor (SN).
The cleaning operation is started according to the detected temperature signal of 2).

The cleaning work executing means (C6B) is
Do the following: (1) The toner suction holding member (CLp, CLy to CL)
k, CL1, CL2), the toner adsorbed and held on the toner image carrier (PR, Py to Pk, B1, Reverse transfer to B2). (2) Each toner image carrier (PR; Py to Pk; Py)
The toner on the surfaces (Pk, B1, B2) is moved to the cleaner-attached toner image carrier (B, B3) by the transfer bias control means (C1). (3) The cleaner bias control means (C4) causes the cleaner (CLt) to collect the toner on the surface of the toner image bearing member (B, B3) with the cleaner. The cleaning operation ending means (C6C) of the cleaning operation control means (C6) ends the cleaning operation at the set timing.

Further, the image forming apparatus of the present invention has the above structural requirements (A01 '), (A02), (A03 "), (A04"),
(A05), (A06 ″), (A07 ″), (A08), (A0
9) and the following constituent requirements (A011) and (A012 ″) are provided: (A011) Environmental temperature sensor (SN3) for detecting the temperature inside the image forming apparatus, (A012 ″) The toner adsorption The toner adsorbed and held by the holding members (CLp, CLy to CLk, CL1, CL2) is transferred to the toner adsorption transfer control means (C).
The toner image carrier (PR, Py to Pk, B) with the holding member is applied by the reverse transfer bias applying means (C3B) of 3).
1, B2) and the toner on the surface of the toner image carrier (PR, Py to Pk, B1, B2) with the holding member is cleaned by the transfer bias control means (C1). The cleaning operation is executed by moving the toner to the cleaner (CLb, CL3) by the cleaner bias control means (C4) by moving the cleaner to the cleaner image carrier (B, B3). Means (C6B) and cleaning work starting means (C6A) for starting the cleaning work in response to the temperature signal detected by the fixing device temperature sensor (SN2) and the temperature signal detected by the environmental temperature sensor (SN3). Cleaning operation ending means (C6C) for ending the cleaning operation at a predetermined timing
Cleaning work control means (C6) having and.

The above structural requirements (A01 '), (A02), (A
03 ″), (A04 ″), (A05), (A06 ″), (A0
7 "), (A08), (A09), (A011), (A012")
In the image forming apparatus of the present invention, the fixing device temperature sensor (SN2) detects the temperature of the fixing device (F) that fixes the toner image transferred to the recording sheet (S).
The environmental temperature sensor (SN3) detects the temperature inside the image forming apparatus. The cleaning work starting means (C6A) of the cleaning work control means (C6) starts the cleaning work in response to the temperature signal detected by the fixing device temperature sensor (SN2) and the temperature signal detected by the environment temperature sensor (SN3). The processing by the cleaning work executing means (C6B) and the cleaning work ending means (C6C) is as described above.

Further, the image forming apparatus of the present invention is characterized by having the following constituent requirements (B01) to (B06). (B01) A plurality of toner adhering rotary members (PR, B, T2b; which rotate in contact with each other to adhere a toner image to the surface;
Py to Pk, B, T2b; Py to Pk, B1 to B3, T
2b), (B02) the plurality of toner adhering rotary members (P
R, B, T2b; Py to Pk, B, T2b; Py to P
k, B1 to B3, T2b), the toner adhering rotary members (PR, B, T2b; Py to Pk, which rotate in contact with each other).
B, T2b; Py to Pk, B1 to B3, T2b), and a toner transfer bias applying member for transferring toner (B0
3) The plurality of toner adhering rotary members (PR, B, T2)
b; Py to Pk, B, T2b; Py to Pk, B1 to B
Cleaner (CLb, CL) for collecting the toner adhering to any one or more of the toner adhering rotary members (3, T2b).
t), (B04) Toner adhering rotary member (B, T2b) for collecting toner by the cleaner (CLb; CLt)
Other toner-attached rotating members (PR, T2b; Py to P
k, T2b; Py to Pk, B1, B2, T2b), the toner adsorbing and holding members (CLp, CLt; CLy to CLk, CLt; CLy to
CLk, CL1, CL2, CLt; CLy to CLk, C
(L1 to CL3), (B05) fixing device temperature sensor (SN2) for detecting the temperature of the fixing device (F) for fixing the toner image transferred to the recording sheet (S), (B06) the toner adsorption holding member (B06) CLp, CLt; CLy to CLk, CL
t; CLy to CLk, CL1, CL2, CLt; CLy
To CLk, CL1 to CL3), the toner adsorbed and held on the toner adhering rotary members (PR, B, T2b; Py to Pk,
B, T2b; Py to Pk, B1 to B3, T2b) and the toner adhering rotary member (PR, B, T2).
b; Py to Pk, B, T2b; Py to Pk, B1 to B
3, T2b) toner on the cleaner (CLb, C
Lt) transfers the toner to the toner adhering rotary member (B; B3; T2b) from which the cleaner (C
Lb, CL3, CLt) cleaning work execution means (C6) for executing a cleaning work for collecting the toner.
B), a cleaning work starting means (C6A) for starting the cleaning work in response to a temperature signal detected by the fixing device temperature sensor (SN2), and a cleaning work ending means (C6A) for ending the cleaning work at a set timing. C6C) and cleaning operation control means (C6).

In the image forming apparatus of the present invention having the above structural requirements (B01) to (B06), a plurality of toner adhering rotary members (PR,
B, T2b; Py to Pk, B, T2b; Py to Pk, B
1 to B3, T2b), the toner attached to the surface of any one or more toner adhering rotary members is directly collected by the cleaner (CLb, CLt). A toner adhering rotary member (PR, T2b; Py to Pk, other than the toner adhering rotary member whose toner is directly collected by the cleaner).
In T2b; Py to Pk, B1 to B3), the toner adhering to the surface of the toner is held by the toner adsorption holding members (CLp, CL).
t; CLy to CLk, CLt; CLy to CLk, CL
1, CL2, CLt; CLy to CLk, CL1 to CL
It is temporarily adsorbed and held by 3). The fixing device temperature sensor (SN2) detects the temperature of the fixing device (F) that fixes the toner image transferred to the recording sheet (S).
The cleaning work starting means (C6A) of the cleaning work control means (C6) is the fixing device temperature sensor (SN).
The cleaning operation is started according to the detected temperature signal of 2). The cleaning operation executing means (C6B) is configured to operate the toner adsorption holding members (CLp, CLt; CLy to CLk, C).
Lt; CLy to CLk, CL1, CL2, CLt; CL
The toner adsorbed and held on y to CLk, CL1 to CL3) is attached to the toner adhering rotary member (PR, B, T2b; Py to P).
k, B, T2b; Py to Pk, B1 to B3, T2b) and the toner adhering rotary member (PR, B, T2b).
T2b; Py to Pk, B, T2b; Py to Pk, B1
B3, T2b) toner on the surface of the cleaner (CLb,
CLt) transfers the toner to the toner-adhering rotary member (B; B3; T2b) from which the cleaner (C
A cleaning operation is performed to collect the toner in Lb, CL3, and CLt). Cleaning work ending means (C6
In C), the cleaning work is finished at the set timing.

Further, the image forming apparatus of the present invention has the above structural requirements (B01) to (B05) and the following structural requirements (B07) and (B0).
It is characterized by having 8). (B07) Environmental temperature sensor (SN3) for detecting the temperature inside the image forming apparatus, (B08) The toner adsorption / holding member (C)
Lp, CLt; CLy to CLk, CLt; CLy to CL
k, CL1, CL2, CLt; CLy to CLk, CL1
To CL3), the toner adsorbed and held on the toner adhering rotary member (PR, B, T2b; Py to Pk, B, T2b; Py).
To Pk, B1 to B3, T2b) and the toner adhering rotary member (PR, B, T2b; Py to Pk,
B, T2b; Py to Pk, B1 to B3, T2b) The toner adhering rotary member (B; B3; T2b) whose toner is collected by the cleaner (CLb, CLt).
The cleaner (CLb, CL3, CL
cleaning work executing means (C6B) for executing the cleaning work for collecting the toner in t), the fixing device temperature sensor (SN2) and the environmental temperature sensor (SN).
Cleaning work control means (C6C) having a cleaning work starting means (C6A) for starting the cleaning work in response to the detected temperature signal of 3) and a cleaning work ending means (C6C) for ending the cleaning work at a set timing ( C6).

The above structural requirements (B01) to (B05), (B0
In the image forming apparatus of the present invention including 7) and (B08), the environmental temperature sensor (SN3) detects the temperature inside the image forming apparatus. The cleaning work starting means (C6A) of the cleaning work control means (C6) starts the cleaning work according to the temperature signals detected by the fixing device temperature sensor (SN2) and the environmental temperature sensor (SN3). The processing by the cleaning work executing means (C6B) and the cleaning work ending means (C6C) is as described above.

When the temperature difference between the detected temperature of the fixing device detected by the fixing device temperature sensor (SN2) and the fixable temperature is equal to or more than the set value, the fixing device has not performed the fixing operation for a long time. That is, it is possible to determine that image formation has not been performed for a long period of time and start cleaning. Further, even when the temperature difference is not equal to or more than a set value, it is possible to limit the cleaning period to a period in which the temperature of the fixing device rises to the fixable temperature and execute the cleaning. The set value can be configured to be automatically changed according to the environment or the set condition. Further, when the temperature difference between the detected temperature and the environmental temperature (temperature inside the image forming apparatus) is less than or equal to a set value, it is determined that image formation has not been performed for a long period of time, and cleaning is started. Is also possible. By adopting such a configuration, the cleaning is executed only when the image formation is not performed for a long time, that is, when the charge of the residual toner is lowered and the image quality may be deteriorated, and the cleaning is executed. Therefore, the time for image formation is not affected, and a decrease in image recording efficiency (productivity) can be prevented.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiments) Next, specific examples (embodiments) of the embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. Absent. (Embodiment 1) FIG. 1 is an overall explanatory view of Embodiment 1 of an image forming apparatus of the present invention. In FIG. 1, the image forming apparatus U is
An automatic document feeder U1 and an image forming apparatus main body (copier) U2 having a platen glass PG supporting the automatic document feeder U1 are provided. The automatic document feeder U1 has a document feed tray T on which a plurality of documents Gi to be copied are stacked and placed.
G1 and the original feed tray TG1 to the platen glass P
It has a document discharge tray TG2 from which a document Gi conveyed through a copy position (document reading position) on G is discharged. The image forming apparatus main body U2 has a UI (user interface) through which a user inputs and operates an operation command signal such as copy start, an exposure optical system A, and the like. Reflected light from a document transported on the platen glass PG by the automatic document transport device U1 or a document (not shown) manually placed on the platen glass PG is transmitted through the exposure optical system A to a CCD ( R (red), G (green),
It is converted into a B (blue) electric signal. An IPS (image processing system) outputs the RGB electrical signals as Y signals.
(Yellow), M (magenta), C (cyan), K
It is converted into (black) image data and temporarily stored, and the image data is output to the laser drive circuit DL at a predetermined timing.

The surface of the drum-shaped photoconductor PR that rotates and moves in the direction of the arrow Ya is uniformly charged by the charging roll (charging member) CR, and the latent image forming position Q1, the developing area Q2, and the primary transfer area Q3. Sequentially pass through.

A ROS (latent image forming device) driven by the laser drive circuit DL exposes and scans the surface of the photoconductor PR at the latent image forming position Q1 by the laser beam L, and an electrostatic latent image is formed on the surface of the photoconductor PR. To form. When forming a full-color image, electrostatic latent images corresponding to four-color images of Y (yellow), M (magenta), C (cyan), and K (black) are sequentially formed, and in the case of a monochrome image, K is formed.
Only the electrostatic latent image corresponding to the (black) image is formed. To write the latent image on the photoconductor PR by the laser beam L, the belt position sensor SNb is set by using the reference mark Bm (see FIG. 1) provided on the non-image portion of the intermediate transfer belt (intermediate toner image carrier) B described later. Is started after a lapse of a predetermined time from detection. When forming a full-color image with the rotary developing device, the respective colors are superposed, so that the time from the detection of the reference mark Bm by the belt position sensor SNb to the start of the latent image writing by the laser beam L is the same for each color. .

The rotary type developing device G is sequentially rotated and moved to the developing area Q2 in accordance with the rotation of the rotating shaft Ga.
(Yellow), M (magenta), C (cyan), K
It has four (black) color developing devices GY, GM, GC and GK. The developing devices GY, GM, GC, and GK for the respective colors have a developing roll GR that conveys the developer to the developing area Q2, and the electrostatic latent image on the photoconductor PR passing through the developing area Q2 is tonered. The image Tn is developed. The toner image forming device (PR + CR + ROS +) is formed by the photoconductor PR, the charging roll CR, the ROS (latent image forming device), the developing device G, and the like.
G) is configured.

A slide frame F1 (2) is provided below the photoconductor PR by a pair of left and right slide rails SR, SR.
It is supported so as to be slidable back and forth (direction perpendicular to the image plane). A belt frame F2 of the belt module BM is supported on the slide frame F1 so as to be vertically rotatable around a hinge shaft F2a. The belt module BM includes a plurality of belt support rolls (Rd, Rt, Rf, T2a) that rotatably support the intermediate transfer belt (transfer toner image carrier) B, a primary transfer roll T1, and a contact roll. It has T2c and the belt frame F2 that supports them. The plurality of belt support rolls (Rd, Rt, Rf, T2a)
Includes a belt driving roll Rd, a tension roll Rt, an idler roll (free roll) Rf and a backup roll T2a, and the contact roll T2c is in contact with the backup roll T2a.

The belt module BM is rotatable up and down around the hinge shaft F2a, and when it is rotated downward, the belt module BM does not come into frictional contact with the photoconductor PR together with the slide frame F1. Body U2
You can get in and out of. The primary transfer roller T1 configured as the primary transfer device receives the toner image Tn on the surface of the photoconductor PR when a transfer voltage having a polarity opposite to the charging polarity of the toner is applied by the power supply circuit E controlled by the controller C.
Is primarily transferred to the intermediate transfer belt B in the primary transfer area Q3. In the case of a full-color image, the toner images Tn of the respective colors sequentially formed on the surface of the photoconductor PR are primary-transferred one after another on the surface of the intermediate transfer belt B in the primary transfer area Q3, and finally, a full-color multiple toner image. Are formed on the intermediate transfer belt B. When forming a monochromatic monocolor image, only one developing device is used, and the monochromatic toner image is primarily transferred onto the intermediate transfer belt B. After the first transfer,
The surface of the photoconductor PR is destaticized by the destaticizing roll JR, and the residual toner is cleaned by a brush-shaped photoconductor toner adsorption holding member CLp configured as a photoconductor cleaner.

Below the backup roll T2a, a secondary transfer slide frame Fs slidable forward and backward (a direction perpendicular to the paper surface) by a pair of left and right slide rails SR, SR is provided with respect to the image forming apparatus main body U2. It is detachably supported. A secondary transfer elevating frame Ft of the sheet transfer unit Ut is supported on the secondary transfer slide frame Fs so as to be vertically rotatable around a hinge axis Fta. The sheet transfer unit Ut can be moved in and out of the image forming apparatus main body U2 without being in frictional contact with the belt module BM in a state of being rotated downward.
The sheet transfer unit Ut includes a secondary transfer roll (that is, a sheet transfer roll that transfers toner to a recording sheet) T2b, a brush-shaped roll toner suction holding member CLt configured as a secondary transfer roll cleaner, and a roll. Support lever Lr, post-transfer sheet guide SG2,
The sheet transport belt BH and the secondary transfer elevating frame Ft that supports the sheet transport belt BH are provided.

The roll support lever Lr is a lever for supporting the secondary transfer roll (sheet transfer roll) T2b and the roll toner suction holding member CLt, and is rotated around the hinge axis La by a motor (not shown) or the like. The secondary transfer roll T2b is moved between a secondary transfer area that contacts the intermediate transfer belt B and a standby position that is separated from the intermediate transfer belt B. The secondary transfer roll T2b
A secondary transfer area Q4 is formed by the contact area of the intermediate transfer belt B, and the secondary transfer roll T2b, the backup roll T2a, and the contact roll T2.
The secondary transfer device T2 is constituted by c. The intermediate transfer belt B, the primary transfer device T1, and the secondary transfer device T2 constitute a transfer device (B + T1 + T2) that transfers the toner image on the surface of the photoconductor PR to the recording sheet S.

The recording sheets S stored in the paper feed tray TR1 are taken out by the pickup roll Rp at a predetermined timing, separated one by one by the separating roll Rs, and conveyed to the registration roll Rr. The cash register roll Rr
The recording sheet S conveyed to the pre-transfer sheet guide S is timed to move the primary-transferred multiple toner image or single-color toner image to the secondary transfer area Q4.
It is conveyed from G1 to the secondary transfer area Q4. When the recording sheet S passes through the secondary transfer area Q4, the secondary transfer device T2
A secondary transfer voltage having the same polarity as the charging polarity of the toner is applied to the contact roll T2c from the power supply circuit E controlled by the controller C. The secondary transfer device T2 secondarily transfers the color toner images, which are primary-transferred overlappingly on the intermediate transfer belt B, to the recording sheet S collectively in the secondary transfer area Q4. Therefore, the toner image forming device (P
R + CR + ROS + G) and the transfer device (B + T1)
+ T2), a toner image is formed on the toner image forming surface of the recording sheet S.

The residual toner on the intermediate transfer belt B after the secondary transfer is collected by the belt cleaner CLb. Further, the toner adhering to the surface of the secondary transfer roll T2b is primarily adsorbed and held by the roll toner adsorbing and holding member CLt. The secondary transfer roll T2b and the belt cleaner CLb are arranged so as to be able to separate from and contact (separate and contact) with the intermediate transfer belt B, and when a color image is formed, an unfixed toner image of the final color is formed. On the intermediate transfer belt B 1
It is separated from the intermediate transfer belt B until the next transfer. The roll toner suction holding member CLt is
The contact and separation movement is performed together with the secondary transfer roll T2b. The recording sheet S to which the toner image is secondarily transferred is conveyed to the fixing area Q5 by the post-transfer sheet guide SG2 and the sheet conveying belt BH. The fixing area Q5 includes a heating roll (fixing heating rotating member, recording sheet holding rotating member) Fh and a pressure belt (fixing pressing rotating member, recording sheet holding rotating member) Fp (a pair of recording sheet holding rotating members Fh and Fp) is a region formed by a pressure contact region (recording sheet holding portion). The recording sheet S has the heating roll Fh and the pressure belt Fp when passing through the fixing area Q5.
It is heated and fixed by a fixing device F (fixing device) having a.
The recording sheet S on which the toner image is fixed is discharged to the recording sheet discharge tray TR2. The symbols Rp, Rs, R
The sheet conveying device SH (Rp, Rs, Rr, SG1, SG2, BH) by the elements indicated by r, SG1, SG2, BH
Is configured.

(Belt cleaner CLb) FIG.
2A is a diagram showing the belt cleaner shown in FIG. 2A, showing the state in which the belt cleaner is in contact with the intermediate transfer belt and has moved to a cleaning position for cleaning the toner on the intermediate transfer belt. FIG. It is a figure which shows the state which moved to the standby position separated from the belt. In FIG. 2, the belt cleaner CLb is arranged so as to face the portion of the intermediate transfer belt B wound around the belt drive roll Rd. The belt cleaner CLb
Is a cleaning case 1 which is rotatable about a hinge shaft 1a, a tension spring 2 which operates to rotate the cleaning case 1 in a counterclockwise direction at all times, and the cleaning case 1 is separated from and in contact with the intermediate transfer belt B. It has a cam 3 for making it.

The belt cleaner CLb has a cleaning blade 4 whose edge (tip portion) contacts the intermediate transfer belt B on the belt driving roll Rd, a cleaning brush 5 rotatably supported in the cleaning case 1, and Metal brush cleaning roll 6
And a scraper member 7 that comes into contact with the surface of the brush cleaning roll 6 and mechanically scrapes the toner from the brush cleaning roll 6, and a toner transport auger 8 that carries the scraped toner to a toner collecting device (not shown). Have

The toner remaining on the intermediate transfer belt (intermediate toner image carrier) B that has passed through the secondary transfer area Q4 is belt cleaner CLb together with the intermediate transfer belt B.
Is transported to the position. The toner remaining on the intermediate transfer belt B receives a mechanical scraping force from the cleaning brush 5 rotating in the direction opposite to the direction of the intermediate transfer belt B, and the adhesion force with the intermediate transfer belt is weakened. The toner whose adhesion has been weakened moves to the cleaning brush 5 by a bias having a polarity opposite to the charging potential of the toner applied to the cleaning brush 5, and the toner that has not moved to the cleaning brush 5 is provided downstream of the cleaning brush. It is scraped off by the blade 2. In the first embodiment, the bias potential of V1 = + 500V is applied to the cleaning brush 5 when the − (minus) charged toner is collected,
When collecting + (plus) charged toner, V2 = -7
A bias potential of 00V is applied.

The toner adsorbed on the cleaning brush 5 is carried to the contact portion with the brush cleaning roll 6 arranged so as to contact the cleaning brush 5. To the brush cleaning roll 6, a bias having a polarity opposite to the charging potential of the toner and having a larger absolute value than the bias applied to the cleaning brush 5 is applied,
The toner reaching the contact portion is cleaned by the cleaning brush 5.
Under the action of an electric field formed between the brush cleaning roll 6 and the brush cleaning roll 6, the electrostatic charge moves to the surface of the brush cleaning roll 6. In the first embodiment, when the − (minus) charged toner is collected on the brush cleaning roll 6 (when the bias potential of V1 = + 500V is applied to the cleaning brush 5), V3 = + 700.
When the bias potential of V is applied and the + (plus) charged toner is collected (when V2 = −700V), V4 is applied.
A bias potential of = -900V is applied. The toner adhered to the brush cleaning roll 6 is mechanically mechanically brushed by a scraper member 7 (see FIG. 2) provided in one direction of the doctor (a direction facing the rotation of the brush cleaning roll) at a position downstream of the contact portion. Scraped from 6. The toner scraped off is cleaned by the cleaning brush 5 and the brush cleaning roll 6.
By the toner conveying auger 8 provided below the
The toner is carried to a toner collecting device (not shown).

(Toner suction holding members CLp and CL
t) FIG. 3 is an enlarged view of a main part of FIG. In FIG. 3, the photoconductor toner attracting / holding member CLp and the roll toner attracting / holding member CLt are brush-like members. The toner attracting / holding member CLp for each photoconductor is
V5 = + 500V when attracting (minus) charged toner and when discharging the attracted and held + charged toner
V is applied when the + (plus) charged toner is attracted and when the − charged toner is discharged.
A bias potential of 2 = -700V is applied. Further, a bias potential of V5 = + 700V is applied to the roll toner adsorption / holding member CLt when adsorbing the − (minus) charged toner and discharging the adsorbed / held + charged toner, and the + (plus) charged toner is V2 = -9 when adsorbing and when discharging charged toner
A bias potential of 00V is applied.

(Explanation of Control Section of First Embodiment) FIG. 4 is an explanatory view of a control section of the first embodiment of the image forming apparatus of the present invention, and is a block diagram of each function provided in the control section (functional block diagram). It is the figure shown with. In FIG. 4, the controller C is an I / O (input / output interface) for inputting / outputting signals to / from the outside and adjusting the input / output signal level,
A ROM (read only memory) in which programs and data for performing necessary processing are stored, a RAM (random access memory) for temporarily storing required data, and a program stored in the ROM. It is configured by a computer having a CPU (central processing unit) that performs processing, a clock oscillator, and the like, and various functions can be realized by executing the programs stored in the ROM.

(Signal Output Element Connected to the Controller C) The controller C receives signals from the UI (user interface), the toner concentration sensor SN1, the fixing device temperature sensor SN2, a belt position sensor (not shown), and other signal output elements. The output signal of is input. The UI
Is a display unit UI1, a copy start key UI2, a copy number setting key UI3, a magnification setting key UI4, a ten-key UI
5. Equipped with a sheet type designation key.

(Control element connected to the controller C) Further, the controller C controls the IPS, the main motor drive circuit D1, the developing device rotation drive circuit D2, the heating roll drive circuit D3, the power supply circuit E, and other control elements. They are connected and output their operation control signals. The power supply circuit E is a charging power supply circuit E1, a CLp power supply circuit E2,
Development bias power supply circuit E3, intermediate transfer power supply circuit E
4, sheet transfer power supply circuit E5, CLb power supply circuit E
6, a CLt power supply circuit E7, a heater power supply circuit E8, and the like. The main motor drive circuit D1 rotationally drives the main motor M1, and the main motor M1 drives the photoconductor (primary toner image carrier) PR, charging roll CR, intermediate transfer belt (intermediate toner image carrier) B, primary The transfer roll T1 is rotationally driven. The developing device rotation drive circuit D2 rotates the developing device G via the developing device rotation motor M2, and moves the developing devices Gy to Gk of each color to the developing area Q2. The developing roll driving circuit D3 is a developing roll G of each developing unit Gy to Gk via a GR (developing roll) driving motor M3.
Rotate R. Fh (heating roll) drive circuit D4
Drives the heating roll Fh of the fixing device F to rotate through the Fh (heating roll) drive motor M4.

The charging power source E1 applies a charging bias or the like to the charging roll CR (charge roll). CLp
The power supply circuit E2 applies a toner attraction bias and a toner ejection bias for ejecting the attracted and held toner to the toner attraction and holding member CLp for the photoconductor. The developing bias power source E3 applies a developing bias to the developing roll of each developing device D that has moved to the developing area Q2. The primary transfer power source E4 applies a primary transfer bias to the primary transfer roll T1 that primarily transfers the toner image on the surface of the photoconductor (primary toner image carrier) to the intermediate transfer belt (intermediate toner image carrier) B. Apply. The sheet transfer power supply circuit E5 transfers the toner image on the intermediate transfer belt (intermediate toner image carrier) B onto the recording sheet S or transfers the toner on the secondary transfer roll T2b to the intermediate transfer belt (intermediate toner image carrier). ) A transfer bias is applied to the contact roll T2c when it is moved to the surface. The CLb power supply circuit E6 applies a toner collecting bias to the cleaning brush 5 and the brush cleaning roll 6 of the belt cleaner CLb. The CLt power supply circuit E7 applies a toner suction bias and a toner discharge bias for discharging the held toner to the roll toner suction holding member CLt. The heater power supply circuit E8 applies heater driving power to the heater housed inside the heating roll Fh of the fixing device F.

(Function of Controller C) The controller C has a function of executing processing according to an input signal from the signal output element and outputting a control signal to each of the control elements. That is, the controller C has the following functions. C1: Transfer Bias Control Unit The transfer bias control unit C1 applies a transfer bias to the primary transfer device to transfer the toner between the toner image carriers. C2: sheet transfer roll bias control means (sheet transfer device bias control means) The sheet transfer roll bias control means C2 transfers the toner image on the intermediate transfer belt (intermediate toner image carrier) B to the recording sheet S. A bias is applied to the sheet transfer roll.

C3: Toner Adsorption Transfer Control Means The toner adsorption transfer control means C3 has an adsorption bias applying means C3a and a reverse transfer bias applying means C3b.
A bias for toner transfer is applied between the photoconductor (primary toner image carrier) PR and the toner adsorption / holding member CLp for the image carrier. C3a: Adsorption bias applying means C3a The adsorption bias applying means C3a applies an adsorption transfer bias for transferring the toner on the surface of the photoconductor (primary toner image carrier) PR to the toner adsorption holding member CLp. C3b: Reverse transfer bias applying means C3b reversely transfers the toner attracted and held by the toner attracting / holding member CLp for the photoconductor (for the primary toner image carrier) to the photoconductor (primary toner image carrier) PR. Apply reverse transition bias. C4: Cleaner Bias Control Means The cleaner bias control means C4 applies a cleaning bias for collecting the toner on the surface of the intermediate transfer belt (intermediate toner image carrier) B to the belt cleaner CLb, the cleaning brush 5 and the brush cleaning of the belt cleaner CLb. Apply to roll 6.

C5: Toner transfer control means for rolls The toner transfer control means for rolls C5 has an attraction bias applying means C5A and a reverse transfer bias applying means C5b, and a secondary transfer roll T2b and a roll toner attraction / holding member CLt. A bias for toner transfer is applied between and. C5A: Adsorption bias applying means C5A The adsorption bias applying means C5A is a secondary transfer roll T2.
The toner on the surface b of the roll toner adsorption holding member C
A transfer bias for adsorption that transfers to Lt is applied. C5b: Reverse transfer bias applying means C5b applies a reverse transfer bias for reversely transferring the toner attracted and held by the roll toner suction holding member CLt to the secondary transfer roll T2b.

C6: Cleaning work control means. The cleaning work control means C6 has a cleaning work start means C6A, a cleaning work execution means C6B, and a cleaning work end means C6C, and at the set timing, the toner adsorption holding member CLp for the toner image carrier and the roll toner. A toner cleaning operation of transferring the toner held by the suction holding member CLt to the belt cleaner CLb and collecting the toner is performed. C6A: Cleaning Work Starting Means Cleaning work starting means C6A includes a job starting means C6A1 and a continuous printing starting means C6A.
2, the cleaning operation is started at the set timing. C6A1: Start means at job start The start means at job start C6A1 is set under a condition (detected temperature of the fixing device temperature sensor SN2) when a start signal of a job (image forming operation) is input (when a copy start key is input). The set temperature Tr of the printable fixing device temperature (fixable temperature) set to Tf is Tr−Tf ≧ 100 ° C.)
If the condition is satisfied, the cleaning work is started. C6A2: Continuous Printing Start Unit The continuous printing start unit C6A2 starts the cleaning operation every time the number of continuous print sheets reaches 48.

C6B: Cleaning Work Execution Means The cleaning work execution means C6B uses the reverse transfer bias application means C3b of the toner adsorption transfer control means C3 to apply the toner adsorbed and held by the toner adsorption holding member CLp for the image carrier. The toner on the surface of the primary toner image carrier PR is reversely transferred to the primary toner image carrier PR and is moved to the intermediate transfer belt (intermediate toner image carrier) B by the transfer bias control means C1 to perform the intermediate transfer. The toner on the surface of the belt (intermediate toner image carrier) B is transferred to the belt cleaner C by the cleaner bias control means C4.
A cleaning operation for collecting Lb is performed.

C6C: Cleaning Operation Completion Means The cleaning operation completion means C6C is a cleaning toner density detection means C6C1 for detecting the toner density SN1a during the cleaning operation, and a cleaning operation completion for storing the toner density threshold value Ns for determining the cleaning operation completion. The toner concentration threshold storage unit C6C2 for determination is provided, and the cleaning operation is terminated when the detected concentration signal SN1a of the toner concentration sensor SN1 is SN1a ≦ Ns with respect to the set threshold Ns. For example, when the toner density is detected at a level of 0 to 255 and the detection value SN1a is 0 to 44, the toner density is 0% and the detection value SN1a is 2
In the case of 21 to 255, if the toner density is 100%,
When the detected value SN1a becomes Ns (= 50) or less (that is, when SN1a ≦ 50), the cleaning operation is ended.

C6C1: Toner concentration detecting means for cleaning Toner concentration detecting means for cleaning C6C1 detects the toner concentration SN1a during the cleaning operation based on the input signal from the toner concentration sensor SN1. C6C2: Toner density threshold storage means for cleaning operation end determination Toner density threshold storage means C for cleaning operation end determination
The 6C2 stores a toner density threshold value Ns for determining the end of the cleaning operation, which is used to determine the timing to stop the cleaning operation during the execution of the cleaning operation.

(Operation of First Embodiment) In the first embodiment of the image forming apparatus having the above-mentioned configuration, negative (-) charged toner, that is, negatively charged toner is used. A bias of +500 V is applied to the body toner suction holding member CLp and the roll toner suction holding member CLt to collect the negatively charged toner. These biases are applied by the attracting bias applying means C3A and C5A of the toner attracting and transferring control means C3 and the roll toner transferring control means C5 shown in FIG. When the image forming apparatus is used in such a state, the adsorbed toner is accumulated on the toner adsorbing / holding member CLp for the image carrier and the toner adsorbing / holding member CLt for the roll, and the cleaning performance deteriorates. Further, when image formation is not executed for a long period of time, the charge of the toner is lowered,
The force attracted to the image carrier toner suction holding member CLp and the roll toner suction holding member CLt becomes weak. Then, the toner that cannot be completely adsorbed is discharged to the photoconductor PR and the secondary transfer roll T2b, and the discharged toner is recorded on the sheet and the image quality deteriorates.

Therefore, in the first embodiment, the fixing device detection temperature Tf and the set temperature Tr detected by the fixing device temperature sensor SN2 at the start of the job (that is, when the copy start key UI2 (see FIG. 4) is input) are set. If the following expression (1) is satisfied, cleaning is started. Tr−Tf ≧ T (= 100 ° C.) …………………………………… (1) That is, when the above formula (1) is satisfied, the time until completion of warming up (fixing device F heating roll Fh
The time until the heater reaches the fixing possible temperature is considerably long, so the cleaning operation is performed during that time. When the number of continuous prints reaches 48 or more during execution of the job, the job is interrupted and the cleaning operation is performed. When the cleaning operation is performed at the timing as described above, the cleaning operation is executed only when the temperature difference between the detected temperature Tf and the set temperature Tr is large and the start of image formation is not affected even if the cleaning operation is performed. The large temperature difference means that the temperature of the heating roll Fh is lowered, that is, the image formation is not performed for a long time, and at this time, the charge of the residual toner is lowered. Therefore, by performing the cleaning when the image formation is not performed for a long time, it is possible to prevent the deterioration of the image quality due to the discharge of the residual toner whose charge has been lowered, and to perform the unnecessary cleaning operation. This makes it possible to prevent the image recording efficiency (productivity) from decreasing. Further, since the period during which the image formation is not directly performed is not measured, the power can be turned off.

When the cleaning operation is executed,
As a timing for ending the operation, there may be a method of executing the cleaning operation for a set time and then ending the cleaning operation. In that case, the cleaning time may be longer than necessary. However, by ending the cleaning operation in accordance with the detected toner concentration as in the first embodiment, it is possible to prevent the cleaning operation from being performed for an unnecessarily long time, and image recording efficiency (productivity).
Can be prevented.

(Timing Chart of Main Parts of First Embodiment) FIG. 5 is a diagram showing an example of a timing chart of operations of main parts at the time of starting a job of the image forming apparatus of the first embodiment. FIG. 6 is a diagram showing an example of a timing chart of operations of other main components at the time of starting a job of the image forming apparatus of the first embodiment. The flowcharts corresponding to the time charts of FIGS. 5 and 6 will be described later. Reference numerals ta to tf shown in FIGS. 5 and 6 and FIG.
The meanings of t1 and t2 are as follows. ta: Time required for the toner adsorption / holding member CLp for the image carrier to rotate once. tb: time required for the surface of the photoconductor PR to move from the position of the toner adsorption / holding member CLp for the image carrier (see FIG. 3) to the position of the charging roll CR (see FIG. 3). That is, the time required for the toner discharged from the toner adsorption / holding member CLp for the image carrier to move to the position of the charging roll CR. tc: Time required for the surface of the photoconductor PR to move from the position of the toner adsorption / holding member CLp for the image carrier to the position of the toner density sensor. That is, the toner discharged from the toner adsorption / holding member CLp for the image carrier is the toner concentration sensor SN.
The time it takes to move to position 1.

Td: Time required for the surface of the photoconductor PR to move from the position of the toner adsorption / holding member CLp for the image carrier to the position of the primary transfer device T1. That is, the time required for the toner ejected from the toner adsorption / holding member CLp for the image carrier to move to the position of the primary transfer device T1. te: time required for the toner ejected from the image carrier toner adsorption / holding member CLp to move to the position of the secondary transfer device T2. tf: Time required for the toner discharged from the toner adsorption / holding member CLp for the image carrier to move to the belt cleaner CLb. tg: Time required for the surface of the secondary transfer roll T2b to move from the roll toner adsorption holding member CLt to the secondary transfer area Q4. That is, the roll toner adsorption holding member CL
The time required for the toner discharged from t to move to the secondary transfer area Q4.

T1: Toner suction holding member CL for image carrier
-700V application time to p, that is,-(minus)
Toner ejection time. During this time, the time tc has elapsed from the start time of applying −700 V to CLp, the toner concentration sensor SN1 detects the − (minus) discharge toner concentration on the surface of the photoconductor PR, and then the detected toner concentration is the threshold value. The time until the time when it is detected that
(Time required for CLp to make one rotation) plus time. t2: +50 to the toner adsorption / holding member CLp for the image carrier
0V application time, that is, + (plus) toner discharge time. During this time, the toner concentration sensor SN1 detects the + (plus) ejected toner concentration on the surface of the photoconductor PR after the time tc has elapsed from the start time of + 500V application to CLp,
It is the time obtained by adding the time until the time when it is detected that the detected toner concentration has dropped below the threshold value thereafter and the time ta (the time required for CLp to make one rotation).

In the example of the flowcharts shown in FIGS. 5 and 6, when the copy start key UI2 (see FIG. 4) is input, the following operation is performed. (1) The main motor M1 is turned on. (2) The rotation of the polygon mirror of the ROS (not shown), the heating roll Fh, the toner adsorption / holding member CLp for the image carrier, etc. is also started. (3) The bias of −700 V for discharging − (minus) toner is started to the toner adsorption / holding member CLp for the image carrier. (4) The belt cleaner CLb moves to the cleaning position where it contacts the intermediate transfer belt B. This is cam 3 (Fig. 2
(See) rotation.

(5) Roll toner adsorption holding member CLt
The application of a bias of −900V for − (minus) toner discharge is started. (6) The contact roll T2c of the secondary transfer device T2 is
A bias of + 500V for transferring − (minus) charged toner for transferring − (minus) charged toner discharged from the CLt to the surface of the secondary transfer roll T2b is applied. The bias application time of +500 V is tg + t1. (7) The cleaning brush 5 of the belt cleaner CLb ejected from the CLt to the surface of the secondary transfer roll T2b and further transferred to the intermediate transfer belt B- (minus)
A bias of +500 V is applied to collect the charged toner.

(8) In FIG. 6, after the copy start key UI2 is turned on to the secondary transfer device T2, a time te has elapsed, and then the toner adsorption holding member CLp for the image carrier discharges the negative (-) charge. The toner reaches the secondary transfer device T2. Therefore, the contact roll T2c of the secondary transfer device T2 is configured such that the − (minus) charged toner discharged at CLp is transferred to the secondary transfer roll after a time te has elapsed since the copy start key UI2 was turned on. To prevent this, a bias of -700V is applied only for time t1,
Further, in order to prevent the + (plus) charged toner from transferring to the secondary transfer roll, + 500V for a time t2.
Bias is applied. (9) In FIG. 6, after the time tf has elapsed since the copy start key UI2 was turned on, the- (minus) charged toner discharged by the toner adsorption / holding member CLp for the image carrier is applied to the cleaning brush 5 of the belt cleaner CLb. To reach. Therefore, a bias of + 500V is applied to the cleaning brush 5 only for the time t1 in order to collect the − (minus) charged toner discharged at CLp after the time tf has elapsed since the copy start key UI2 was turned on. Further, subsequently, a bias of −700 V is applied for a time t2 in order to collect the + (plus) charged toner.

(Description of Flowchart of Cleaning Operation at Job Start of First Embodiment) FIG. 7 is a flowchart of a main routine of a job of the image forming apparatus of the first embodiment. Each ST (step) in the flowchart of FIG.
The process is performed according to the program stored in the ROM of the controller C. Further, this processing is executed by multitasking in parallel with other various processing of the image forming apparatus. In ST (step) 1 of FIG. 7, it is determined whether or not the copy start key is turned on. If no (N), ST1 is repeatedly executed. If yes (Y), move to next ST2. The following process is executed in ST2. (1) Start rotation of the main motor M1, secondary transfer roll rotation drive motor, ROS polygon mirror rotation drive motor, and other motors. That is, warm-up is started. (2) Heating heater built in the heating roll Fh, ROS
Start warming up the laser diode, etc.

In ST3, the heating roll F of the fixing device F
Detection temperature Tf of h and printable fixing device temperature set temperature Tr
And Tr−Tf ≧ 100 ° C. are determined. If yes (Y), move to ST4; if no (N), ST
Go to 5. In ST4, the cleaning operation is executed. This ST4 subroutine will be described later. S
At T5, it is determined whether the warm-up is completed. If no (N), ST5 is repeatedly executed. If yes (Y), move to ST6. In ST6, the job (image forming operation) is executed. This image forming operation is performed in the same manner as a normal image forming apparatus operation. During the job execution, the cleaning operation is executed every time the continuous print number reaches 50. When the job in ST6 is completed, the process returns to ST1.

The cleaning operation in ST4 and the execution of the job in ST6 are performed by controlling the toner adsorption / holding member CLp for the image carrier, the primary transfer device T1, the secondary transfer device T2, and the roll toner adsorption. Since the control of the holding member CLt, the control of the belt cleaner CLb, etc. are executed by multitasking (parallel processing), ST5 can be omitted. In that case, directly from ST4 to ST6
However, the printing efficiency will be higher if this is done.

FIG. 8 is a flowchart of the ST4 cleaning operation subroutine shown in FIG. 7, and is a flowchart of bias control of the toner adsorption / holding member for the image carrier during the cleaning operation. The flowchart of FIG. 8 is executed by multitasking in parallel with other flowcharts. In ST11 of FIG. 8, the following processing is performed. (1) A bias of -700 V is applied to the toner adsorption / holding member CLp for the image carrier to eject the-(minus) charged toner. (2) Turn on the clock timer TM1. In ST12, it is determined whether TM1> tc. TM1
When> tc, the toner discharged in ST11 has reached the position of the toner concentration sensor SN1.
If the answer is NO in ST12, ST12 is repeatedly executed. If yes (Y), move to ST13.

At ST13, the toner concentration sensor SN1
Detection density SN1a and toner concentration setting value Ns are SN1
It is determined whether or not a ≦ Ns. ST14 for no (N)
Move on to. In ST14, it is determined whether TM1 ≧ 5ta. If no (N), the process returns to ST13. ST14
In the case of YES (Y), after the TM1> tc is satisfied (after the discharged (-) charged toner reaches the position of the toner concentration sensor SN1), the toner adsorption / holding member CLp for the image carrier is 5 This means that the rotation time (ta × 5) has elapsed. In this case, even if SN1a ≦ Ns is not satisfied, the process proceeds to ST17.

If YES (Y) in ST13, and if SN1a ≦ Ns, the detected toner density SN1.
It means that a is equal to or less than the set value (threshold value) Ns. In the case of this yes (Y), it moves to ST15. ST1
In step 5, TM2 = ta is set in the timer TM2.
In ST16, it is determined whether or not the timer TM2 has timed out. If no (N) in ST16, ST
16 is repeatedly executed. If the answer is YES (Y) (time is up), the toner concentration S detected in ST13 is detected.
After N1a becomes the set value (threshold value) Ns or less, time t
It means that “a” has elapsed (that is, (−) toner has been ejected while CLp makes one further rotation after SN1a ≦ Ns is satisfied). In addition, ST14, ST15
Can be omitted. Yes in ST16 (Y)
In the case of, move to ST17.

In ST17, the following process is executed. (1) The measured time of the timer TM1, that is, the (−) charged toner discharge execution time t1 is stored in the (−) toner discharge execution time storage memory. (2) +500 for the toner adsorption / holding member CLp for the image carrier
A V (+) charged toner discharge bias is applied. ST
18, the measurement time TM1 of the timer TM1 is TM1>
It is determined whether t1 + ta. ST1 for no (N)
Repeat step 8. Yes in ST18 (Y)
In this case, it means that a time ta (the time from the position of CLp to the position of the toner density sensor SN1) has elapsed after the (+)-charged toner discharge bias of +500 V is applied to CLp. Move on to.

At ST19, the toner concentration sensor SN1
Detection density SN1a and toner concentration setting value Ns are SN1
It is determined whether or not a ≦ Ns. ST20 for no (N)
Move on to. In ST20, it is determined whether TM1 ≧ t1 + 5ta. If no (N), the process returns to ST19. S
If YES in T19, TM1> t
Time after which 1 + tc is reached (after the discharged (+) charged toner reaches the position of the toner density sensor SN1), the toner adsorption / holding member CLp for the image carrier is rotated 5 times (ta
It means that x5) has passed. In this case, SN1
Even if a ≦ Ns is not satisfied, the process proceeds to ST23.

If YES in ST19, if SN1a≤Ns, the detected toner concentration SN1.
It means that a is equal to or less than the set value (threshold value) Ns. In the case of this yes (Y), it moves to ST21. ST2
At 1, the timer TM3 is set to TM3 = ta.
In ST22, it is determined whether or not the timer TM3 has timed out. If no (N) in ST22, ST
22 is repeatedly executed. If yes (Y) (time up), the toner concentration S detected in ST19 is detected.
After N1a becomes the set value (threshold value) Ns or less, time t
It means that a has elapsed (that is, (+) toner has been ejected for one more rotation of CLp after SN1a ≦ Ns). In addition, ST21, ST22
Can be omitted. Yes at ST22 (Y)
In the case of, move to ST23.

In ST23, the following processing is executed. (1) The time obtained by subtracting the (-) charged toner discharge execution time t1 from the measurement time TM1 of the timer TM1, that is,
The (+) toner discharge execution time t2 is stored in the (+) toner discharge execution time storage memory. (2) +50 to the toner adsorption / holding member CLp for the image carrier
The application of the 0 V (+) charged toner discharge bias is stopped. Next, the process returns to ST5 of the main routine of FIG. In addition,
As described above, ST5 can be omitted. If ST5 is omitted, the process returns to ST6.

FIG. 9 is a flowchart of the ST4 cleaning operation subroutine shown in FIG. 7, and is a flowchart of the bias control of the intermediate transfer roll during the cleaning operation. The flowchart of FIG. 9 is executed by multitasking in parallel with other flowcharts. S in FIG.
At T31, it is determined whether TM1> td. ST31
In, the measured time TM1 of the timer TM1 is TM1> td
Judge whether or not. If no (N), ST31 is repeatedly executed. If yes (Y) in ST31,
-700V is applied to the toner attracting / holding member CLp for the image carrier.
Time td from application of the (-) charged toner discharge bias (time until the (-) charged toner discharged at CLp moves from the position CLp to the position of the primary transfer unit T1)
Has passed. At this time, the process proceeds to ST32.

In ST32, the primary transfer device T1 is +50.
By applying 0 V, the (−) charged toner on the surface of the photoconductor (primary toner image carrier) PR is primarily transferred to the intermediate transfer belt B. In ST33, it is determined whether or not TM1 ≧ td + t1. If no (N), ST33 is repeatedly executed.
If YES in ST33, TM1 ≧
After td (toner adsorption / holding member CL for image carrier)
This means that the time t1 has elapsed since the (−) charged toner ejected at p reached the position of the primary transfer device T1. At this time, the (+) charged toner ejected by the toner adsorption / holding member CLp for the image carrier reaches the position of the primary transfer device T1. In this case, the process proceeds to ST34.

At ST34, the primary transfer device T1 is set to -70.
Applying 0V (+) charged toner transfer bias,
PR of (+) charged toner to photoconductor (primary toner image carrier)
To the intermediate transfer belt B. T in ST35
It is determined whether M1 ≧ td + t1 + t2. In the case of no (N), ST35 is repeatedly executed. If YES in ST35, after TM1 ≧ td + t1 is satisfied (after the (+) charged toner ejected by the toner adsorption / holding member CLp for the image carrier reaches the position of the primary transfer unit T1. ) It means that time t2 has elapsed. At this time, the (+) charged toner ejected to the photoconductor (primary toner image carrier) PR by the toner adsorption / holding member CLp for the image carrier is transferred to the intermediate transfer belt B by the primary transfer device T1. become. In this case, the process proceeds to ST36. ST3
At 6, the primary transfer bias for the (+) charged toner of the primary transfer device T1 is stopped. Next, the process returns to ST5 of the main routine of FIG. As described above, ST5 can be omitted. If ST5 is omitted, the process returns to ST6.

FIG. 10 is a flow chart of the ST4 cleaning operation subroutine shown in FIG. 7, and is a flow chart of the bias control of the secondary transfer roll and the roll toner suction holding member during the cleaning operation. This FIG.
6 corresponds to the time chart of the applied bias of CLt and the applied bias of the contact roll T2c in FIG. The flowchart of FIG. 10 is executed by multitasking in parallel with other flowcharts. Further, in the first embodiment, the toner discharge processing of the roll toner suction holding member CLt is performed in synchronization with the toner discharge processing of the image carrier toner suction holding member CLp, but it may be performed without synchronization. Is also possible.
In ST41 of FIG. 10, the following processing is performed. (1) A bias of -900V is applied to the roll toner adsorption / holding member CLt in order to eject the-(minus) charged toner. (2) The secondary transfer roll (sheet transfer device) T2b is grounded. (3) A transfer bias of +500 V is applied to the contact roll T2c.

In ST42, it is determined whether or not the application of the (+)-charged toner discharge bias of +500 V to the toner adsorption / holding member CLp for the image carrier has started. No (N)
In this case, ST42 is repeatedly executed. If yes (Y), the process moves to ST43. In ST43, the discharge of the (+) charged toner of the roll toner suction holding member CLt is started in synchronization with the start of the discharge of the (+) charged toner of the toner suction holding member CLp for the image carrier. + 700V is applied to the holding member CLt. Then S
At T44, it is determined whether TM1 ≧ tg + t1. If no (N), ST44 is repeatedly executed. In the case of yes (Y), since the (+) charged toner discharged from CLt to the secondary transfer roll T2b has reached the secondary transfer area Q4, the (+) charged toner is transferred to the intermediate transfer belt B. Need to be transferred. If yes (Y), the process moves to ST45. In ST45, a (+) charged toner transfer bias of −700 V is applied to the contact roll T2c to move the toner on the secondary transfer roll T2b onto the intermediate transfer belt B.

At ST46, it is determined whether or not the measurement time TM1 of the timer TM1 ≧ tg + t1 + t2. No (N)
In this case, ST46 is repeatedly executed. In the case of yes (Y), the last part of the (+) charged toner discharged from CLt to the secondary transfer roll T2b has passed the secondary transfer area Q4. In the case of this Yes (Y), ST47
Move on to. In ST47, the bias application to the contact roll T2c is stopped. In the processing up to this point, the toner discharge from the roll toner suction holding member CLt and the transfer processing of the discharged toner to the intermediate transfer belt B are completed.
Next, it is necessary to apply a bias for preventing transfer of the toner discharged from the toner adsorption / holding member CLp for the image carrier to the secondary transfer roll T2b side.

At ST48, it is determined whether or not TM1 ≧ te. If no (N), ST48 is repeatedly executed. In the case of Yes (Y), the (−) charged toner discharged from the image carrier toner adsorption / holding member CLp to the photoconductor (primary toner image carrier) PR has reached the secondary transfer region Q4. become. In this case, the process proceeds to ST49. ST4
9, in order to prevent the (−) charged toner on the intermediate transfer belt B from transferring to the secondary transfer roll T2b, a transfer prevention bias of + 500V is applied to the contact roll T2c. In ST50, it is determined whether or not TM1 ≧ te + t1. If no (N), ST50 is repeatedly executed. In the case of Yes (Y), the (+) charged toner ejected from the image carrier toner adsorption / holding member CLp to the photoconductor PR has reached the secondary transfer area Q4, and therefore the (+) charged toner is used. Must be prevented from being transferred to the secondary transfer roll T2b. If yes (Y), the process moves to ST51.

At ST51, the contact roll T2
A (+)-charged toner transfer prevention bias of −700 V is applied to c. TM1 ≧ te + t1 + t2 in ST52
Judge whether or not. If no (N), ST52 is repeatedly executed. In the case of Yes (Y), the last part of the (+) charged toner discharged from the image carrier toner adsorption / holding member CLp to the photoconductor PR has passed through the secondary transfer area Q4 (time in FIG. 6). See chart). In the case of this yes (Y), it moves to ST53. In ST53, the bias application to the contact roll T2c is stopped. With the above processing, the bias application control of the secondary transfer device T2 and the roll toner adsorption / holding member CLt during the cleaning operation is completed.

FIG. 11 is a flowchart of the ST4 cleaning operation subroutine shown in FIG. 7, and is a flowchart of the bias control of the belt cleaner CLb during the cleaning operation. The flowchart of FIG. 11 is the same as that of FIG.
It corresponds to the time chart of the brush bias of the cleaner. In FIG. 6, only the time chart of the cleaning brush of the belt cleaner CLb is shown, and the timing chart of the brush cleaning roll 6 is omitted because the screen space is insufficient. The flowchart of FIG. 11 is executed by multitasking in parallel with other flowcharts. In ST61 of FIG. 11, the following processing is performed. (1) The cam drive motor that rotationally drives the cam 3 (see FIG. 2) is driven to move the cleaner to the cleaning position (the position shown in FIG. 2A). (2) A +500 V (−) charged toner collecting bias is applied to the cleaning brush 5. The (-) charged toner collected at this time is the roll toner adsorption holding member CL.
The toner ejected from t. (3) A + 700V (-) charged toner collecting bias is applied to the brush cleaning roll 6. The (-) charged toner collected at this time is the toner ejected from the roll toner adsorption holding member CLt.

Next, in ST62, TM1 ≧ tg + (t
f-te) + t1 is determined. If no (N), ST62 is repeatedly executed. If yes (Y),
Since the (+) charged toner discharged from the roll toner adsorption / holding member CLt has reached the belt cleaner CLb, it is necessary to transfer the (+) charged toner from the intermediate transfer belt B to the belt cleaner CLb. If yes (Y), the process moves to ST63. In ST63, the following process is executed. (1) A bias of −700V for (+) charged toner is applied to the cleaning brush 5 so that the (+) charged toner on the intermediate transfer belt B (roller toner attracting / holding member CL).
The toner ejected from t) is collected. (2) -900V is applied to the brush cleaning roll 6 to move the toner on the cleaning brush 5 onto the brush cleaning roll 6. The toner transferred to the brush cleaning roll 6 is scraped by the scraper member (see FIG.
(Refer to 7) Scraped by 7 and toner transport auger 8
(See FIG. 2), the toner is carried to a toner collecting device (not shown).

In ST64, it is determined whether or not the measurement time TM1 of the timer TM1≥tg + tf-te + t1 + t2. If no (N), ST64 is repeatedly executed.
If yes (Y), CLt to secondary transfer roll T2b
This means that the last portion of the (+) charged toner discharged to the belt cleaner CLb has reached the belt cleaner CLb. This Jesus (Y)
In the case of, move to ST65. The following process is executed in ST65. (1) Stop applying bias to the cleaning brush 5. (2) Stop applying bias to the brush cleaning roll 6. By the processing up to this point, the roll toner adsorption holding member C
The process of collecting the toner discharged from Lt ends. next,
It is necessary to collect the toner discharged from the toner adsorption / holding member CLp for the image carrier.

At ST66, it is determined whether or not TM1 ≧ tf. If no (N), ST66 is repeatedly executed. In the case of Yes (Y), the (−) charged toner discharged from the toner adsorption / holding member CLp for the image carrier to the photoconductor (primary toner image carrier) PR has reached the belt cleaner CLb. . In this case, the process proceeds to ST67. S
At T67, the following process is executed to collect the (−) charged toner on the intermediate transfer belt B. (1) A +500 V (−) charged toner collecting bias is applied to the cleaning brush 5 so that the (−) charged toner on the intermediate transfer belt B (toner adsorption / holding member C for image carrier).
The toner ejected from Lp) is collected. (2) + 700V is applied to the brush cleaning roll 6 to move the toner on the cleaning brush 5 onto the brush cleaning roll 6.

Next, in ST68, TM1 ≧ tf + t1
Judge whether or not. In the case of no (N), ST68 is repeatedly executed. In the case of yes (Y), since the (+) charged toner discharged from the toner adsorption / holding member CLp for the image carrier has reached the belt cleaner CLb, the above (+)
Transfer charged toner from intermediate transfer belt B to belt cleaner CL
It is necessary to transfer to b. If yes (Y), the process moves to ST69. The following process is executed in ST69. (1) A bias of −700V for (+) charged toner is applied to the cleaning brush 5 so that the (+) charged toner on the intermediate transfer belt B (roller toner attracting / holding member CL).
The toner ejected from t) is collected. (2) -900V is applied to the brush cleaning roll 6 to move the toner on the cleaning brush 5 onto the brush cleaning roll 6.

In ST70, it is determined whether or not the measurement time TM1 of the timer TM1 ≧ tf + t1 + t2. No (N)
In the case of, ST70 is repeatedly executed. In the case of Yes (Y), the last part of the (+) charged toner discharged from the image carrier toner adsorption / holding member CLp to the photoconductor PR has reached the belt cleaner CLb. In the case of this yes (Y), it moves to ST70. The following process is performed in ST70. (1) Stop applying bias to the cleaning brush 5. (2) Stop applying bias to the brush cleaning roll 6. By the processing up to this point, the roll toner suction holding member CLt and the image carrier toner suction holding member CLt
The process of collecting the toner discharged from p is completed.

(Embodiment 2) FIG. 12 is an overall explanatory view of an image forming apparatus according to Embodiment 2 of the present invention and corresponds to FIG. 1 of Embodiment 1. In the description of the second embodiment, constituent elements corresponding to those of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. This Example 2
Is different from Example 1 in the following points, but is configured similarly to Example 1 in other points. The image forming apparatus of the first embodiment is a color copying machine equipped with a rotary developing device, but the image forming apparatus shown in FIG. 12 is a tandem type color printer. In FIG. 12, the color printer U has a toner dispenser device Ua for supplying toner. Color printer U Y (yellow), M (magenta), C (cyan), K
(Black) toner image forming devices UY, UM, UC, U
K latent image forming device ROSy, ROSm, ROSc, RO
Sk emits a laser beam for image writing according to the laser drive signal of the laser drive circuit DL of each color. The controller C outputs control signals for the laser drive circuit DL and the power supply circuit E.

In FIG. 12, the drum-shaped photosensitive member (primary toner image bearing member) P of the K (black) toner image forming device UK is shown.
Around the k, a charging roll CRk as a charging device, a developing device Gk, a toner adsorption holding member CLk for an image carrier, and the like are arranged. Then, the other toner image forming devices UY, U
M, UC of the photoconductor (primary toner image carrier) Py, P
Also around m and Pc, charging devices CRy, CRm and CRc, and developing devices Gy and G similar to those around the photoconductor Pk, respectively.
m, Gc, toner adsorption holding members CLy, CL for image carrier
m, CLc, etc. are arranged. Toner suction holding members CLk, CLy, CLm, CL for the image carrier of the second embodiment
c is the toner adsorption / holding member C for the image carrier of the first embodiment
It has the same configuration as Lp.

In FIG. 12, the photoconductors (primary toner image carrier) Py, Pm, Pc and Pk are uniformly charged by the charging rolls CRy, CRm, CRc and CRk, respectively, and then the latent image forming device is formed. ROSy, ROSm, ROS
An electrostatic latent image is formed on the surface by the laser beam output from c and ROSk. The photoconductors Py, Pm, Pc,
The electrostatic latent image on the surface of Pk is the developing device Gy, Gm, Gc, Gk.
Is developed into toner images of Y (yellow), M (magenta), C (cyan), and K (black). The developing devices Gy, Gm, Gc, and Gk are configured to be replenished with toner from toner cartridges (not shown) of the respective colors mounted on the toner dispenser device Ua.

The toner images on the surfaces of the photoconductors Py, Pm, Pc and Pk (see FIG. 12) are transferred to the intermediate transfer belt (intermediate toner image bearing by primary transfer rolls T1y, T1m, T1c and T1k as primary transfer devices). A color image is formed on the intermediate transfer belt B by sequentially transferring the images onto the body B. In the case of only black image data, only the K (black) photoconductor Pk and the developing device Gk are used, and only a black toner image is formed. After the primary transfer, photoconductors Py, Pm, Pc, Pk
The residual toner on the surface is the toner adsorption holding member CL for the photoconductor.
It is primarily adsorbed and held by y, CLm, CLc, and CLk.

Photosensitive members Py, Pm, Pc, Pk of the respective colors
The intermediate transfer belt B and the belt drive roll R are located below
d, tension roll Rt, backup roll T2a
A plurality of belt supporting rolls (Rd, Rt, T2a,
Rf, Rw) are arranged. The intermediate transfer belt B is supported by the plurality of belt supporting rolls so as to be rotatable and movable in the arrow Ya direction.

A sheet transfer unit Ut is arranged below the backup roll T2a. Secondary transfer roll (sheet transfer roll) T of the sheet transfer unit Ut
2b is arranged so as to be able to separate and press contact (separate contact) with the backup roll T2a with the intermediate transfer belt B interposed therebetween, and the secondary transfer roll T2b has a region (nip) in which the secondary transfer roll T2b is in pressure contact with the intermediate transfer belt B. A next transfer area Q4 is formed. A brush-shaped roll toner adsorption holding member CLt is in contact with the secondary transfer roll T2b. The roll toner adsorption / holding member CLt of the second embodiment is configured similarly to the roll toner adsorption / holding member CLt of the first embodiment, and has the same operation. Below the intermediate transfer belt B, the paper feed tray TR1 and the paper feed tray T are provided.
Sheet conveyance path S for conveying the sheet S taken out from R1
An H1, a sheet circulation path SH2, and a sheet reversal path SH3 are arranged.

Sheets S stored in the paper feed tray TR1
Are picked up by a pickup roll Rp at a predetermined timing, separated one by one by a separating roll Rs,
The sheet is conveyed to the registration roll Rr by the conveying roller Ra on the sheet conveying path SH1. The recording sheet S conveyed to the registration roll Rr is secondarily transferred from the pre-transfer sheet guide SG1 at the same timing as the first-transferred multiple toner image or single-color toner image is moved to the second transfer area Q4. It is transported to the area Q4.

A contact roll T2c is in contact with the backup roll T2a, and when the recording sheet S passes through the secondary transfer area, the contact roll T2c has the same polarity as the charging polarity of the toner at the same timing. A secondary transfer voltage is applied. At this time, the toner image is transferred from the intermediate transfer belt B to the recording sheet S. The rolls T2a to T2c constitute a secondary transfer device T2. The intermediate transfer belt B after the secondary transfer is cleaned by the belt cleaner CLb. The belt cleaner CLb of the second embodiment has the same structure as the belt cleaner CLb of the first embodiment.

The recording sheet S to which the toner image is secondarily transferred is conveyed to the fixing device F through the post-transfer sheet guide SG2 and the conveying belt BH. On the recording sheet S, the toner image is heat-fixed when passing through the fixing area Q5 where the heating rolls Fh and Fp of the fixing device are in pressure contact with each other. Alternatively, the sheet is conveyed to the sheet circulation path SH2. The recording sheet conveyed to the sheet discharge roller Rh is discharged to the sheet discharge tray TR2. Seat circuit SH
The recording sheet conveyed to No. 2 is conveyed to the sheet inversion path SH3 by the switching gate G2, inverted, and then switched back to be retransmitted from the sheet circulation path SH2 to the secondary transfer area Q4 through the registration roll Rr.

(Operation of Second Embodiment) As in the first embodiment, the color printer U of the second embodiment having the above-described structure is similar to the first embodiment in that during the job (image forming operation), each photoconductor (primary toner image carrier). ) The toner adhering to the surface of Py, Pm, Pc, Pk is the toner adsorption holding member CLk, CLy, C for the image carrier.
It is temporarily adsorbed and held by Lm and CLc. Also, 2
The toner adhering to the surface of the next transfer roll T2b is temporarily adsorbed and held by the roll toner adsorbing and holding member CLt. The belt cleaner CLb is the intermediate transfer belt B.
The toner adhering to the surface is collected.

(Explanation of Flowchart of Cleaning Operation at Job Start of Second Embodiment) FIG. 13 shows the second embodiment.
9 is a flowchart of a main routine of a job of the image forming apparatus of FIG. 7, corresponding to FIG. 7 of the first embodiment. Figure 1
The processing of each ST (step) in the flowchart of FIG. 3 is performed according to the program stored in the ROM of the controller C. Further, this processing is executed by multitasking in parallel with other various processing of the image forming apparatus. The processing of each ST in FIG. 13 is different from that of the first exemplary embodiment in the following points, but the same processing is performed in other points, and thus detailed description will be omitted.

In ST3, the heating roll F of the fixing device F
Detection temperature Tf of h and printable fixing device temperature set temperature Tr
And Tr−Tf ≧ 100 ° C. are determined. If yes (Y), move to ST4; if no (N), ST
Move to 3-1. In ST3-1, tz = (Tr-T
f) / Th processing is performed, and the process proceeds to ST3-2. The fixing device temperature increase rate Th is a rate at which the temperature of the fixing device rises per unit time, and the value of the temperature increase rate Th is measured in advance and recorded in the nonvolatile RAM. Regarding the fixing device temperature rise rate Th, the set temperature Tr and the detected temperature Tf, the value of (Tr−Tf) / Th is the temperature of the heating roll Fh from the detected temperature Tf to the printable fixer temperature (set temperature). ) It means the time required to rise to Tr. Therefore, this time is shortened. Cleaning period t
Put it as z.

At ST3-2, it is determined whether tz> tf. If yes (Y), the process moves to ST3-3, and if no (N), the process moves to ST5 and the cleaning is not executed. During the cleaning operation, ta to tg are necessary and cannot be shortened. Therefore, when the shortened cleaning period tz is shorter than the longest period tf from ta to tg, even if the cleaning operation is started, the heating roll Fh does not reach the printable fixing device temperature Tr before the cleaning is completed. Reached and is ready to print. At this time, the start of printing must be delayed until the end of cleaning, and the delayed time is the time at which the start of printing is delayed as it is, so that the image forming efficiency (productivity) is reduced. Therefore,
If the shortened cleaning period tz is longer than tf, cleaning is performed, and if tz is tf or less, cleaning is not performed. By setting the value for comparing tz to be not tf, for example, tc or td, it is possible to control when printing is started during the cleaning operation without waiting for the end of cleaning.

In ST3-3, t1 = t2 = (tz
-Tf) / 2 processing is performed, and the process proceeds to ST4 '. In the first embodiment, t1 and t2 set based on the time measured by the clock timer TM1 are set by the values of tz and tf. That is, this t1, t
By setting 2, the time for discharging −toner and + toner is determined, so the cleaning operation is performed only for the period of tz, and at the same time when the heating roll Fh reaches the printable fixing device temperature, the cleaning is completed. However, cleaning is performed without affecting the start of printing. Regarding t1 and t2, in the second embodiment, t1 = t2 is set, but other settings, for example, t1 = tz−tf, t2 = 0.
A setting such as (-cleaning only toner) is also possible.

FIG. 14 is a flowchart of a subroutine of the shortening cleaning operation in ST4 'of FIG. 13 and is a flowchart of bias control of the toner adsorption holding member for the image carrier during the shortening cleaning operation. In ST4 ', the shortened cleaning operation is executed, and after the shortened cleaning operation is completed, the process proceeds to ST5. In addition, as in the first embodiment, S
When T5 is omitted, the process proceeds to ST6. In the shortening cleaning operation of ST4 ', processing different from the cleaning operation of ST4 is performed in the following points, but the other processing is the same, and thus detailed description thereof is omitted. In ST3-3, since the time for discharging −toner and + toner is set, the processing for setting t1 and t2 performed in ST17 and ST23 in the first embodiment is not performed in ST17 ′ and ST23 ′ in the second embodiment. Further, in ST14 and ST20 of Example 1, a process of controlling to forcibly end the toner discharge was performed due to the relationship between the time measured by TM1 and 5 ta. However, in the shortening cleaning operation of the second embodiment, the toner discharge time is set to t1.
In ST14 ′, the relationship between the time measured time of 1 and t1 is T
M1 ≧ t1, TM1 ≧ t1 + t2 in ST20 ′
In this case, the process of forcibly ending the toner discharge is performed. Other bias control of members and the like are t1, t2 set in ST17 and St23 in the first embodiment.
However, in the second embodiment, the processing is performed based on ST.
The processing and control performed in each ST (step) are the same, except that the processing is performed based on t1 and t2 set in 3-3. Therefore, detailed description is omitted.

The image forming apparatus of the second embodiment has an effect on the start of image recording not only when the temperature difference between the detected temperature Tf and the set temperature Tr is large (100 ° C.) but also when the cleaning operation is executed. Execute the cleaning operation within the range that does not exist. Therefore, similarly to the image forming apparatus of the first embodiment, the image forming apparatus of the second embodiment can prevent deterioration of image quality and reduction of image recording efficiency (productivity) due to discharge of residual toner.

(Third Embodiment) FIG. 15 is an overall explanatory view of an image forming apparatus according to a third embodiment of the present invention and corresponds to FIG. 12 of the second embodiment. In the description of the third embodiment,
The constituent elements corresponding to those of the second embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. The third embodiment differs from the second embodiment in the following points, but is configured similarly to the second embodiment in other points. In the image forming apparatus of the second embodiment, the intermediate toner image carrier is composed of the intermediate transfer belt B, but in the image forming apparatus of the third embodiment, two drum-shaped primary intermediate toner image carriers B1, B2 and one drum-shaped secondary intermediate toner image carrier B3. The primary intermediate toner image carrier B
1, B2 and the secondary intermediate toner image carrier B3 are members having a dielectric layer formed on the surface of a cylindrical aluminum sleeve, and a bias is applied to the aluminum sleeve. Further, in the second embodiment, the charger is composed of the charging rolls CRy to CRk, whereas in the third embodiment, the charger is composed of the charging corotron (discharger) CCy to CCk. In the third embodiment, the toner concentration sensors SNy to SNk of the second embodiment are omitted.

The primary intermediate toner image carrier B1 is a photosensitive member (1
The primary toner image carrier Py, Pm and the secondary intermediate toner image carrier B3 are in contact with each other in the primary transfer areas Qy, Qm.
Then, the photoconductors (primary toner image carrier) Py, Pm
The Y (yellow) and M (magenta) toner images formed on the primary transfer areas Q1y and Q1m are primarily transferred to the primary intermediate toner image carrier B1 in an overlapping manner and then transferred to the intermediate transfer area Q31. The image is transferred to the secondary intermediate toner image carrier B3. The primary intermediate toner image carrier B2 is a photosensitive member (1
The primary toner image carrier Pc, Pk and the secondary intermediate toner image carrier B3 are in contact with each other in the primary transfer areas Qc, Qk.
Then, the photoconductors (primary toner image carrier) Pc, Pk
The C (cyan) and K (black) toner images formed above are 1
In the secondary transfer areas Qc and Qk, the primary intermediate toner image carrier B
In the intermediate transfer area Q32, the secondary intermediate toner image carrier B3 is Y (yellow), M
It is transferred onto the (magenta) toner in an overlapping manner. Y, M, which are transferred and superposed on the secondary intermediate toner image carrier B3
The toner images of the four colors of C and K are the secondary intermediate toner image carrier B
3 is transferred onto the recording sheet S passing through a sheet transfer area Q4 which is a pressure contact area between the third transfer roller T2 and the secondary transfer roller T2.

The primary intermediate toner image bearing members B1 and B
The toner adsorption / holding member C for the primary intermediate toner image carrier is provided downstream of the intermediate transfer areas Q31 and Q32 in the rotation direction of 2.
L1 and CL2 are arranged. Further, adjacent to the surface of the secondary intermediate toner image carrier B3, the sheet transfer area Q
4, a toner image density sensor SN1 and an intermediate toner image carrier cleaner CL3 are disposed downstream of the toner image density sensor SN1. The cleaner CL3 for the intermediate toner image carrier is the same as in the first and second embodiments.
The belt cleaner CLb has the same structure.

In FIG. 15, an environmental temperature sensor SN3 for detecting the temperature inside the image forming apparatus is provided above the conveying roller Ra inside the image forming apparatus U. The ambient temperature sensor SN3 can be provided at any place where a typical temperature inside the image forming apparatus can be detected.

(Operation of Third Embodiment) In the image forming apparatus of the third embodiment of the present invention having the above-described structure, during the cleaning operation, the toner discharged from the toner adsorption / holding members CLy and CLm for the image carrier is the photoconductor. (Primary toner image carrier) P
Transferred from y, Pm to the primary intermediate toner image carrier B1,
Further, it is transferred to the secondary intermediate toner image carrier B3. The toner transferred to the secondary intermediate toner image carrier B3 (toner ejected from the toner attracting and holding members CLy and CLm for the image carrier) has an intermediate toner image carried after the toner image density sensor SN1 detects the density. It is collected by the body cleaner CL3. The toner ejected from the primary intermediate toner image carrier toner adsorption / holding member CL1 to the primary intermediate toner image carrier B1 is transferred to the secondary intermediate toner image carrier B3, and the toner image density sensor SN1 performs density. After being detected, the toner is collected by the cleaner CL3 for the intermediate toner image carrier.

Toner adsorption holding members CLc, C for image carrier
The toner discharged from Lk is transferred from the photoconductors (primary toner image bearing members) Pc and Pk to the primary intermediate toner image bearing member B2 and further to the secondary intermediate toner image bearing member B3. The toner transferred to the secondary intermediate toner image carrier B3 (toner ejected from the toner attracting / holding members CLc, CLk for the image carrier) is borne by the toner image density sensor SN1 after the density is detected. Cleaner C for body
Recovered at L3. Further, from the toner suction holding member CL2 for the primary intermediate toner image carrier to the primary intermediate toner image carrier B
The toner discharged to No. 2 is transferred to the secondary intermediate toner image carrier B3, the density is detected by the toner image density sensor SN1, and then collected by the intermediate toner image carrier cleaner CL3.

During the cleaning operation, the roll toner adsorption / holding member CLt moves from the secondary transfer roll T2.
The toner ejected on the surface b is transferred from the secondary transfer roll T2b to the secondary intermediate toner image carrier B3, the density is detected by the toner image density sensor SN1, and then collected by the intermediate toner image carrier cleaner CL3. To be done.

(Explanation of Flowchart of Cleaning Operation at Job Start of Third Embodiment) FIG. 16 shows the third embodiment.
9 is a flowchart of a main routine of a job of the image forming apparatus of FIG. 7, corresponding to FIG. 7 of the first embodiment. Figure 1
The processing of each ST (step) in the flowchart of 6 is performed according to the program stored in the ROM of the controller C. Further, this processing is executed by multitasking in parallel with other various processing of the image forming apparatus. Figure 1
The various processes of No. 6 are different from those of the first embodiment in the following points, but the other processes are the same as those of the first embodiment, and detailed description thereof will be omitted.

In ST3 ', | Te-Tf | ≤T'
(= 10 ° C.) is determined. If yes (Y), the process moves to ST4, and if no (N), the process moves to ST5 and the cleaning is not executed. The environmental temperature Te and the detected temperature Tf
When the temperature difference between the heating roll Fh and the temperature T is equal to or less than the set value T ′ (= 10 ° C.), the temperature difference between the temperature of the heating roll Fh and the temperature Te inside the image forming apparatus is small, and the heating roll Fh does not operate for a long time. That is, it represents a situation where image formation is not performed for a long period of time.

Therefore, the image forming apparatus of the third embodiment is
As in the first embodiment, since cleaning is performed only when image formation is not performed for a long period of time, the image quality is prevented from deteriorating due to the discharge of the residual toner whose charge has decreased, and the image is generated by performing unnecessary cleaning operation. It is possible to prevent a decrease in recording efficiency (productivity).

(Modifications) Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-mentioned embodiments, but is within the scope of the gist of the present invention described in the claims. Thus, various changes can be made. A modified embodiment of the present invention is illustrated below. (H01) In Examples 1 to 3, the cleaner CLb,
It is possible to configure CL3 as a toner adsorption / holding member for temporarily holding the toner and configure the roll toner adsorption / holding member CLt of Examples 1 to 3 as a toner recovery cleaner. (H02) In the third embodiment, the toner adsorbing / holding member CL1 for the primary intermediate toner image carrier is configured as a cleaner for collecting toner, and the cleaner CL3 for the intermediate toner image carrying member is used for temporarily adsorbing toner. It can be configured as a member. (H03) In each of the above embodiments, the cleaner for collecting toner may be provided not only at one location but at a plurality of locations. (H04) In each of the above-described embodiments, the end of the cleaning work is set by the detected density signal of the toner concentration sensor SN1, but the end of the cleaning work may be set by arbitrary end determination control. .

[0119]

The image forming apparatus of the present invention described above can achieve the following effects. (E01) By appropriately setting the start condition of the cleaning operation, the cleaning operation can be executed only when the charge of the residual toner is reduced and the time for image formation is not affected.

[Brief description of drawings]

FIG. 1 is an overall explanatory view of a first embodiment of an image forming apparatus of the present invention.

FIG. 2 is an explanatory view of the belt cleaner shown in FIG. 1, and FIG. 2A is a diagram showing a state where the belt cleaner comes into contact with the intermediate transfer belt and moves to a cleaning position for cleaning toner on the intermediate transfer belt. 2B is a diagram showing a state in which the belt cleaner CLb has moved to a standby position separated from the intermediate transfer belt.

FIG. 3 is an enlarged view of a main part of FIG.

FIG. 4 is an explanatory diagram of a control part of the first embodiment of the image forming apparatus of the present invention, and is a block diagram (functional block diagram) showing each function of the control part.

FIG. 5 is a diagram illustrating an example of a timing chart of operations of main components at the time of starting a job of the image forming apparatus according to the first embodiment.

FIG. 6 is a diagram illustrating an example of a timing chart of operations of other main components at the time of starting a job of the image forming apparatus according to the first embodiment.

FIG. 7 is a flowchart of a job main routine of the image forming apparatus according to the first exemplary embodiment.

8 is a flowchart of a subroutine of the ST4 cleaning operation of FIG. 7 and is a flowchart of bias control of the toner adsorption / holding member for the image carrier during the cleaning operation.

9 is a flowchart of a subroutine of the ST4 cleaning operation of FIG. 7, which is a flowchart of bias control of the intermediate transfer roll during the cleaning operation.

10 is a flowchart of a subroutine of the ST4 cleaning operation of FIG. 7 and is a flowchart of bias control of the secondary transfer roll and the toner adsorption / holding member for the roll during the cleaning operation.

11 is a flowchart of a subroutine of the ST4 cleaning operation of FIG. 7, which is a flowchart of bias control of the belt cleaner CLb during the cleaning operation.

FIG. 12 is an overall explanatory diagram of an image forming apparatus according to a second embodiment of the present invention and is a diagram corresponding to FIG. 1 of the first embodiment.

FIG. 13 is a flowchart of a job main routine of the image forming apparatus according to the second embodiment.
9 is a view corresponding to FIG. 7 in FIG.

FIG. 14 is a flowchart of a subroutine of the shortening cleaning operation of ST4 ′ of FIG. 13, which is a flowchart of bias control of the toner adsorption / holding member for the image carrier during the shortening cleaning operation.

FIG. 15 is an overall explanatory diagram of an image forming apparatus according to a third embodiment of the present invention and is a diagram corresponding to FIG. 12 of the second embodiment.

FIG. 16 is a flowchart of a main routine of a job of the image forming apparatus according to the third embodiment.
9 is a view corresponding to FIG. 7 in FIG.

[Explanation of symbols]

B, B1 to B3 ... Intermediate toner image carrier, C1 ... Transfer bias control means, C2 ... Sheet transfer device bias control means, C3 ... Toner adsorption transfer control means, C3A ... Adsorption bias application means, C3B ... Reverse transfer bias application Means, C4 ... Cleaner bias control means, C5 ... Transfer roll toner adsorption transfer control means, C5A ... Adsorption bias application means, C5B ... Reverse transfer bias application means, C6 ... Cleaning work control means, C6A ... Cleaning work start means, C6B ... Cleaning work executing means, C6C ... Cleaning work ending means, CLb, CL3 ... Cleaner, CLp, CLy to CLk, CL1, CL2 ... Toner suction holding member, CLt ... Transfer roll toner suction holding member, F ... Fixing device PR , B; Py to Pk, B; Py to Pk, B1 to B3 ...
Toner image carrier, PR, Py to Pk ... Primary toner image carrier, PR, B, T2b; Py to Pk, B, T2b; Py to P
k, B1 to B3, T2b ... Toner adhering rotary member, S ... Recording sheet, SN2 ... Fixer temperature sensor, SN3 ... Environmental temperature sensor, T2 ... Sheet transfer device, T2b ... Sheet transfer roll,

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/16 103 G03G 15/20 109 15/20 109 21/00 312 21/14 372 F term (reference) 2H027 DA03 DA12 DA14 DA32. BA30 BA58 BB01 CA03 CA07 CA11 CA28 CA30 2H134 GA01 GA02 GA05 GA06 GB02 HB08 HB11 HB12 HB16 HB18 HD01 HD06 HF04 HF14 HF16 JA01 JA05 JA14 KA17 KA20 KA28 KA29 KA33 KA40 KB03 KB04 KB05 KB11 KC01 KC02 KF02 KF03 KG04 KG06 KG07 KG08 KH01 KH04 KH07 KJ02 QA04 2H200 FA01 FA02 GA12 GA14 GA23 GA34 GA44 GB13 GB20 GB22 GB30 GB33 HA02 HB08 HB12 HB22 HB48 JA02 JA28 JA29 JA30 JC02 JC03 JC12 JC18 JC19 JC20 LA12 LB03 LB12 LB18 LB38 LB39 LB40 NA02 NA09 PA03 PA10 PA15 PA18 PA22 PB07 PB19 PB22 PB32 PB35 PB39

Claims (11)

[Claims] 1. An image forming apparatus characterized by comprising the following constituent requirements (A01) to (A010), and a toner image formed on a surface of (A01) and a primary member carrying the formed toner image. A plurality of toner image bearing members including a toner image bearing member and an intermediate toner image bearing member onto which a toner image on the surface of the primary toner image bearing member is transferred; (A02) a toner image on the intermediate toner image bearing member Sheet transfer device that transfers to recording sheet,
(A03) A cleaner disposed adjacent to the surface of the intermediate toner image carrier to recover the toner adhering to the surface into a toner recovery container, (A04) disposed adjacent to the surface of the primary toner image carrier. (A05) transfer bias control means for applying a transfer bias for transferring the toner between the respective toner image carriers, (A06) the toner adsorption holding member for temporarily adsorbing and holding the toner adhering to the surface Adsorption bias applying means for applying an adsorption transfer bias for transferring the toner on the surface of the next toner image carrier to the toner adsorption holding member, and the toner adsorbed and held on the toner adsorption holding member by the primary toner image carrier. (A07) The toner on the surface of the intermediate toner image carrier, which has a reverse transfer bias applying means for applying a reverse transfer bias for reverse transfer to Cleaner bias control means for applying a cleaning bias for collecting the cleaning bias to the cleaner,
(A08) Sheet transfer device bias control means for applying a sheet transfer bias for transferring the toner image on the intermediate toner image carrier to a recording sheet to the sheet transfer device, (A09) the toner image transferred to the recording sheet A fixing device temperature sensor for detecting the temperature of the fixing device for fixing the toner, (A010) the toner adsorbed and held by the toner adsorbing and holding member by the reverse transfer bias applying means of the toner transfer control means for the toner image carrier. The toner on the surface of the intermediate toner image carrier is reversely transferred to the intermediate toner image carrier and the toner on the surface of the primary toner image carrier is moved to the intermediate toner image carrier by the primary toner image transfer bias applying means. Cleaning work executing means for executing a cleaning operation for collecting the toner by the cleaning bias applying means to the cleaner; Cleaning work control means having a cleaning work starting means for starting the cleaning work according to a temperature signal detected by the fixing device temperature sensor, and a cleaning work ending means for ending the cleaning work at a set timing. 2. The following constituent requirements (A01) to (A09),
An image forming apparatus including (A011) and (A012), a primary toner image carrier on which a toner image is formed on a surface of (A01) and which carries the formed toner image, and the primary toner. A plurality of toner image bearing members including an intermediate toner image bearing member onto which the toner image on the surface of the image bearing member is transferred, (A0
2) A sheet transfer device for transferring the toner image on the intermediate toner image carrier to a recording sheet, (A03) A toner disposed in the vicinity of the surface of the intermediate toner image carrier and attached to the surface is collected in a toner collecting container. A cleaner for collecting, (A04) a toner adsorption holding member which is disposed adjacent to the surface of the primary toner image carrier and temporarily adsorbs and holds the toner adhering to the surface, (A05) each toner image carrier Transfer bias control means for applying a transfer bias for transferring the toner between the bodies, (A06) a suction bias for applying a suction transfer bias for transferring the toner on the surface of the primary toner image carrier to the toner suction holding member Reverse transfer bias applying means for applying a reverse transfer bias that reversely transfers the toner attracted and held by the applying means and the toner attracting and holding member to the primary toner image carrier. A toner adsorption transfer control means having: (A07) a cleaner bias control means for applying a cleaning bias for collecting the toner on the surface of the intermediate toner image carrier to the cleaner; (A08) recording a toner image on the intermediate toner image carrier. A sheet transfer device bias control means for applying a sheet transfer bias for transferring to a sheet to the sheet transfer device; (A09) a fixing device temperature sensor for detecting a temperature of a fixing device for fixing the toner image transferred on the recording sheet; (A011) An environmental temperature sensor for detecting the temperature inside the image forming apparatus, and (A012) the reverse transfer bias applying means of the toner transfer control means for the toner image carrier to transfer the toner attracted and held by the toner suction holding member. Reverse transfer to the primary toner image carrier and transfer the toner on the surface of the primary toner image carrier to the primary toner image transfer Cleaning operation executing means for performing a cleaning operation of moving the toner on the intermediate toner image carrier by the bias applying means and collecting the toner on the surface of the intermediate toner image carrier to the cleaner by the cleaning bias applying means; and the fixing device. Cleaning work having a cleaning work starting means for starting the cleaning work in response to a temperature signal detected by a temperature sensor and a detected temperature signal for the environment temperature sensor, and a cleaning work ending means for ending the cleaning work at a set timing. Control means. 3. The image forming apparatus according to claim 1 or 2, further comprising the following structural requirements (A013) to (A016), and (A013) recording a toner image on the intermediate toner image carrier. (A014) a transfer device configured by a sheet transfer roll for transferring to a sheet, (A014) a transfer disposed adjacent to the surface of the sheet transfer roll, for temporarily adsorbing and holding the toner adhering to the surface of the sheet transfer roll (A015) Adsorption bias applying means for applying an adsorption transfer bias for transferring the toner on the surface of the sheet transfer roll to the toner adsorption holding member; Toner transfer control means for transfer roll having reverse transfer bias applying means for applying reverse transfer bias for reversely transferring toner to the sheet transfer roll (A016) The toner that is attracted and held by the toner attracting and holding member by the reverse transfer bias applying means of the transfer roll toner transfer control means is reversely transferred to the sheet transfer roll, and the sheet transfer device bias control means is used to transfer the sheet. A cleaning operation executing means for moving the toner on the surface of the transfer roll to the intermediate toner image carrier, and performing a cleaning operation for collecting the toner on the surface of the intermediate toner image carrier by the cleaner by the cleaner bias control means; Cleaning work control means having a cleaning work starting means for starting the cleaning work according to a temperature signal detected by the fixing device temperature sensor and a cleaning work ending means for ending the cleaning work at a set timing. 4. The following constituent elements (A013) to (A015),
3. The image forming apparatus according to claim 1, further comprising (A016 '), and (A013) the sheet transfer roll configured to transfer the toner image on the intermediate toner image carrier to a recording sheet. A sheet transfer device, (A014) a toner adsorption holding member for a transfer roll, which is arranged adjacent to the surface of the sheet transfer roll and temporarily adsorbs and holds the toner adhering to the surface of the sheet transfer roll, (A015)
Adsorption bias applying means for applying an adsorption transfer bias for transferring the toner on the surface of the sheet transfer roll to the toner adsorption holding member, and reverse transfer of the toner adsorbed and held by the toner adsorption holding member to the sheet transfer roll. A transfer roll toner transfer control means having a reverse transfer bias applying means for applying a reverse transfer bias;
6 ') Reverse transfer of the toner attracted and held by the toner suction holding member by the reverse transfer bias applying means of the transfer roll toner transfer control means, and the sheet transfer by the sheet transfer device bias control means. The cleaning operation execution means for moving the toner on the surface of the roll to the intermediate toner image carrier, and performing the cleaning operation for collecting the toner on the surface of the intermediate toner image carrier by the cleaner bias control means; A cleaning work starting means for starting the cleaning work in response to the detected temperature signal of the fixing device temperature sensor and the detected temperature signal of the environment temperature sensor; and a cleaning work ending means for ending the cleaning work at a set timing. Cleaning work control means having. 5. The image forming apparatus according to claim 1, further comprising the following constituent requirements (A017) and (A018), and (A017) a plurality of the toner images of different colors are formed. Primary toner image carrier, (A018) A plurality of primary intermediate toner image carriers to which a toner image is transferred from the plurality of primary toner image carriers, wherein the toner adsorbing and holding member is arranged adjacent to the surface. And the primary intermediate toner image carrier,
The secondary intermediate toner image carrier on which the toner images on the surfaces of the plurality of primary intermediate toner image carriers are secondarily transferred, and the cleaner is arranged adjacent to the surface. The intermediate toner image carrier having a carrier. 6. The following constituent elements (A01), (A02 ') to
(A04 '), (A05), (A06') to (A08 '), (A
09), (A010 ′), and an image forming apparatus comprising: (A01) a primary toner image carrier on which a toner image is formed and which carries the formed toner image;
A plurality of toner image bearing members including an intermediate toner image bearing member onto which the toner image on the surface of the next toner image bearing member is transferred, (A0
2 ') A sheet transfer roll for transferring the toner image on the intermediate toner image carrier to a recording sheet; (A03') A toner arranged on the surface of the sheet transfer roll and adhering to the surface of the toner is collected in a toner collecting container. Cleaner to collect, (A0
4 ') a toner adsorption holding member which is arranged adjacent to the surfaces of the plurality of toner image carriers and temporarily adsorbs and holds the toner adhering to the surfaces of the toner image carriers, (A05) each toner image carrier Transfer bias control means for applying a transfer bias for transferring the toner between the bodies, (A06 ') Adsorption for applying a transfer bias for adsorption for transferring the toner on the surface of each of the plurality of toner image bearing members to the toner suction holding member Adsorption transfer control means (A07 ') having a bias application means and a reverse transfer bias applying means for applying a reverse transfer bias for reversely transferring the toner adsorbed and held by the toner adsorbing and holding member to each of the toner image carriers. Cleaner bias control means for applying a cleaning bias for collecting the toner on the surface of the sheet transfer roll to the cleaner, (A08 ') Transfer roller bias control means for applying a sheet transfer bias for transferring the toner image on the toner image bearing member onto a recording sheet in the sheet transfer roller,
(A09) Fixing device temperature sensor for detecting temperature of fixing device for fixing the toner image transferred on the recording sheet,
(A010 ′) The toner attracted and held by the toner attracting and holding member is reversely transferred to the toner image carrier by the reverse transfer bias applying means of the toner adsorption and transfer control means,
The toner on the surface of the primary toner image carrier is moved to the intermediate toner image carrier by the transfer bias control unit, and the toner on the surface of the intermediate toner image carrier is moved to the sheet transfer roll by the transfer roll bias applying unit. And a cleaning operation executing means for executing a cleaning operation for collecting the toner on the surface of the sheet transfer roll by the cleaner bias control means, and a cleaning operation for starting the cleaning operation in response to a temperature signal detected by the fixing device temperature sensor. Cleaning work control means having work start means and cleaning work end means for ending the cleaning work at a set timing. 7. The following constituent elements (A01), (A02 ') to
(A04 '), (A05), (A06') to (A08 '), (A
09), (A011), and (A012 '), an image forming apparatus, and (A01) a primary toner image carrier on which a toner image is formed and which carries the formed toner image. A plurality of toner image bearing members including an intermediate toner image bearing member onto which the toner image on the surface of the primary toner image bearing member is transferred, (A02 ') transferring the toner image on the intermediate toner image bearing member to a recording sheet A sheet transfer roll for (A03 ') a cleaner disposed adjacent to the surface of the sheet transfer roll for collecting the toner adhering to the surface into a toner recovery container, (A04') on the surface of the plurality of toner image carriers A toner adsorbing / holding member which is disposed adjacent to and temporarily adsorbs and holds the toner adhering to the surface of the toner image bearing member;
05) Transfer bias control means for applying a transfer bias for transferring toner between the toner image carriers, (A06 ′)
Adsorption bias applying means for applying an adsorption transfer bias for transferring the toner on the surface of each of the plurality of toner image carriers to the toner adsorption holding member, and the toner adsorbed and held on the toner adsorption holding member by each toner image. Toner adsorption transfer control means having reverse transfer bias applying means for applying reverse transfer bias for reverse transfer to the carrier, (A07 ')
Cleaner bias control means for applying a cleaning bias for collecting the toner on the surface of the sheet transfer roll to the cleaner; (A08 ') a sheet transfer bias for transferring the toner image on the intermediate toner image carrier to a recording sheet; Transfer roll bias control means applied to the roll, (A09) a fixing device temperature sensor that detects the temperature of the fixing device that fixes the toner image transferred to the recording sheet, and (A011) detects the temperature inside the image forming apparatus. Environmental temperature sensor, (A012 ') The toner attracted and held by the toner attracting and holding member is reversely transferred to the toner image carrier by the reverse transfer bias applying means of the toner adsorption transfer control means, and the primary toner image is carried. The toner on the surface of the body is moved to the intermediate toner image carrier by the transfer bias control means and bears the intermediate toner image. Execution of a cleaning operation in which the toner on the surface of the holding member is moved to the sheet transfer roll by the bias applying means for the transfer roll, and the cleaner bias control means performs a cleaning operation for collecting the toner on the surface of the sheet transfer roll to the cleaner. Means, a cleaning work starting means for starting the cleaning work in response to the detected temperature signal of the fixing device temperature sensor and the detected temperature signal of the environment temperature sensor, and a cleaning work ending means for ending the cleaning work at a set timing. Cleaning work control means having: 8. The following constituent elements (A01 ′), (A02),
(A03 ″), (A04 ″), (A05), (A06 ″), (A
07 ″), (A08), (A09), and (A010 ″), and a plurality of (A01 ′) toner images formed on the surface and carrying the formed toner images. A plurality of toner image bearing members including a primary toner image bearing member and an intermediate toner image bearing member onto which a toner image on the surface of the primary toner image bearing member is transferred, (A02) on the intermediate toner image bearing member A sheet transfer device that transfers a toner image onto a recording sheet,
(A03 ″) A toner image bearing member of the plurality of toner image bearing members, a cleaner is disposed adjacent to the surface of the toner image bearing member, and the toner adhering to the surface is collected in the toner collecting container by the cleaner. (A04 ″) A toner image carrier other than the cleaner-bearing toner image carrier, which is a toner image carrier for temporarily adsorbing and retaining the toner adhering to the surface, is adjacent to the surface. Toner image carrier with a holding member arranged in parallel (A05)
Transfer bias control means for applying a transfer bias for transferring toner between the respective toner image carriers, (A06 ″) transfer for adsorption for transferring the toner on the surface of the toner image carrier with the holding member to the toner adsorption holding member Toner adsorption transfer having an adsorption bias application unit for applying a bias and a reverse transfer bias application unit for applying a reverse transfer bias for transferring the toner adsorbed and held by the toner adsorption holding member to the toner image carrier with the holding member. Control means,
(A07 ″) Cleaner bias control means for applying a cleaning bias for collecting the toner on the surface of the toner image carrier with the cleaner to the cleaner, (A08) A sheet for transferring the toner image on the intermediate toner image carrier to a recording sheet A sheet transfer device bias control means for applying a transfer bias to the sheet transfer device; (A09) a fixing device temperature sensor for detecting a temperature of a fixing device for fixing the toner image transferred on the recording sheet; (A010 ″); The toner attracted and held by the toner attracting and holding member is reversely transferred to the toner image carrier with the holding member by the reverse transfer bias applying means of the toner adsorption and transfer control means, and the toner on the surface of the toner image carrier with the holding member is removed. The transfer bias control means moves the toner image carrier with the cleaner to move the toner with the cleaner. Cleaning operation executing means for executing a cleaning operation for collecting the toner on the surface of the carrier by the cleaner bias control means, and cleaning operation starting means for starting the cleaning operation in response to a temperature signal detected by the fixing device temperature sensor. And a cleaning operation control means for ending the cleaning operation at a set timing. 9. The following constituent elements (A01 ′), (A02),
(A03 ″), (A04 ″), (A05), (A06 ″), (A
07 "), (A08), (A09), (A011), (A012")
An image forming apparatus comprising: (A01 ') a plurality of primary toner image bearing members having a toner image formed on the surface thereof and carrying the formed toner images; and the primary toner image bearing member. A plurality of toner image bearing members including an intermediate toner image bearing member onto which a toner image on the surface is transferred, (A02) a sheet transfer device for transferring the toner image on the intermediate toner image bearing member to a recording sheet, (A03 ″) One of the plurality of toner image carriers, a cleaner disposed adjacent to the surface of the toner image carrier, and the toner attached to the surface is collected by the cleaner in a toner collecting container. Image carrier, (A04 ″) A toner image carrier other than the toner image carrier with the cleaner, and a toner attracting / holding member that temporarily attracts and holds the toner adhering to the surface is arranged adjacent to the surface. A holding member with a toner image bearing member, (A05) the transfer bias control means for applying a transfer bias to transfer the toner between the respective toner image carrier,
(A06 ″) Adsorption bias applying means for applying an adsorption transfer bias for transferring the toner on the surface of the toner image bearing member with the holding member to the toner adsorption holding member, and the toner adsorbed and held by the toner adsorption holding member. Toner adsorption transfer control means having a reverse transfer bias applying means for applying a reverse transfer bias for reverse transfer to the toner image carrier with the holding member, (A07 ″) The toner on the surface of the toner image carrier with the cleaner is collected in the cleaner. Cleaner bias control means for applying a cleaning bias,
08) Sheet transfer device bias control means for applying a sheet transfer bias for transferring the toner image on the intermediate toner image carrier to a recording sheet to the sheet transfer device, (A09) transferring the toner image transferred to the recording sheet. A fixing device temperature sensor for detecting the temperature of the fixing device to be fixed, (A011) An environmental temperature sensor for detecting the temperature inside the image forming apparatus, (A011)
2 ″) The toner attracted and held by the toner attracting and holding member is reversely transferred to the toner image carrier with the holding member by the reverse transfer bias applying means of the toner adsorption and transfer control means, and the toner image carrier with the holding member is provided. A cleaning operation in which the toner on the surface is moved to the cleaner-bearing toner image carrier by the transfer bias control means, and the toner on the surface of the cleaner-bearing toner image carrier is collected by the cleaner by the cleaner bias control means. Execution means, cleaning work starting means for starting the cleaning work in response to the detected temperature signal of the fixing device temperature sensor and the detected temperature signal of the environment temperature sensor, and a cleaning work for ending the cleaning work at a set timing. Cleaning work with termination means Control means. 10. An image forming apparatus comprising the following constituent features (B01) to (B06); (B01) a plurality of toner adhering rotating members that rotate in contact with each other and onto which toner images adhere. (B02) Toner transfer bias applying means for transferring toner between the toner adhering rotary members of the plurality of toner adhering rotary members, which rotate in contact with each other, and (B03) At least one of the plurality of toner adhering rotary members. A cleaner that collects the toner adhering to the rotating member,
(B04) A toner adsorption holding member for temporarily adsorbing and holding the toner attached to the toner attachment rotating member other than the toner attachment rotating member whose toner is collected by the cleaner, (B0
5) A fixing device temperature sensor that detects the temperature of the fixing device that fixes the toner image transferred to the recording sheet, and (B06) reversely transfers the toner adsorbed and held by the toner adsorbing and holding member to the toner adhering rotating member. Cleaning operation executing means for transferring the toner on the surface of the toner adhering rotary member to the toner adhering rotary member where the toner is collected by the cleaner, and performing a cleaning operation for collecting the toner by the cleaner; and a fixing device temperature sensor. Cleaning work control means having a cleaning work starting means for starting the cleaning work in response to a detected temperature signal, and a cleaning work ending means for ending the cleaning work at a set timing. 11. The following constituent elements (B01) to (B05),
(B07) and (B08) are provided in the image forming apparatus, (B01) a plurality of toner adhering rotation members that rotate in contact with each other and a toner image adheres to the surface, and (B02) the plurality of toner adhering rotations. Toner transfer bias applying means for transferring the toner between the toner adhering rotary members that rotate in contact with each other, and (B03) collect the toner adhering to any one or more of the toner adhering rotary members. A cleaner, (B04) a toner adsorption holding member for temporarily adsorbing and holding the toner adhering to the toner adhering rotation member other than the toner adhering rotation member from which the toner is collected by the cleaner, (B05) the toner transferred to the recording sheet A fuser temperature sensor that detects the temperature of the fuser that fixes the image, (B07) Environmental temperature sensor that detects the temperature inside the image forming apparatus, (B08) The toner adsorbed and held by the toner adsorbing and holding member is transferred to the toner adhering rotary member in the reverse direction, and the toner on the surface of the toner adhering rotary member is transferred to the toner adhering rotary member where the toner is collected by the cleaner, and the toner is attached to the cleaner. Cleaning work executing means for executing a cleaning work for recovering the toner, cleaning work starting means for starting the cleaning work in response to the temperature signals detected by the fixing device temperature sensor and the environmental temperature sensor, and the cleaning operation at a set timing. Cleaning work control means having a cleaning work end means for ending the work.