Information
-
Patent Grant
-
6532355
-
Patent Number
6,532,355
-
Date Filed
Monday, December 3, 200122 years ago
-
Date Issued
Tuesday, March 11, 200321 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Oblon, Spivak, McClelland, Maier & Neustadt, P.C.
-
CPC
-
US Classifications
Field of Search
US
- 399 358
- 399 359
- 399 360
-
International Classifications
-
Abstract
A toner recycling device of an electrophotographic image forming apparatus conveys collected used toner to a developing device of the image forming apparatus. The toner recycling device includes a powder conveying pump that is driven to convey the collected used toner to the developing device of the image forming apparatus when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value, and an adding device that adds a predetermined constant value to the integrated value when driving of an image bearing member of the image forming apparatus is detected.
Description
CROSS REFERENCE TO RELATED APPLICATION
The present application claims priority and contains subject matter related to Japanese Patent Application No. 2000-367433 filed in the Japanese Patent Office on Dec. 1, 2000, and the entire contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a toner recycling device of electrophotographic image forming apparatuses such as copying machines, printers, facsimile apparatuses, multi-functional apparatuses, etc.
2. Discussion of the Background
An electrophotographic image forming apparatus forms a toner image on a photoconductor by performing charging, optical writing, and developing operations. The toner image formed on the photoconductor is transferred onto a sheet either directly from the photoconductor or via an intermediate transfer member, and thereby an image is recorded on the sheet. After the toner image is transferred onto the sheet, respective residual toner on the photoconductor and the intermediate transfer member are removed by cleaning devices for subsequent image formation starting with a charging operation.
Recently, in such electrophotographic image forming apparatuses, from the view points of effective use of resources, protection of the environment, and reduction of the maintenance expenses, it is widely practiced to recycle residual toner collected by a cleaning device without discarding the collected residual toner. The collected residual toner is transferred to a developing device to be mixed with a new toner for subsequent use.
A known toner recycling device, which recycles residual toner collected by a cleaning device to a developing device, fluidizes and conveys the collected residual toner to the developing device using a powder conveying pump called a Monau pump. In such a toner recycling device, however, if the powder conveying pump is always driven, the airtightness of the powder conveying pump is deteriorated due to abrasion, so that toner scattering is caused, the life of the powder conveying pump is reduced, and the temperature of the pump rises.
Accordingly, a known toner recycling device using a powder conveying pump includes a detecting device to detect the amount of collected toner (e.g., a powder sensor) in a toner reservoir, and is configured such that when the detecting device detects that the collected toner amount has reached a predetermined amount, the powder conveying pump is driven for a predetermined period of time.
The present inventors realized that to eliminate such a collected toner amount detecting device by providing a counting device for counting the number of picture elements of an image which is formed. The picture element counting device counts the number of picture elements of an image which is formed, and based upon the integrated value of the number of picture elements, the toner consumption amount is calculated. When the calculated toner consumption amount reaches a predetermined value, the collected toner amount in the toner reservoir is determined to reach a predetermined amount, and then a powder conveying pump is driven.
In a copying operation in an image forming apparatus, a photocoductor starts to rotate when a sheet starts to be fed from a sheet cassette and continues to rotate until the sheet is discharged from the apparatus. Accordingly, in a one-to-one copying operation in which one copy is obtained from one original, the rotating period time of the photoconductor per one copy is longer than in a continuous copying operation in which a plurality of images are successively obtained from one original. As the rotating period of time of the photoconductor per one copy increases, the background soiling of the photoconductor increases, and thereby causes an increase in toner consumption and consequently an increase in the amount of collected residual toner per one picture element.
The increase in the amount of collected residual toner is significant as the image ratio in an image to be formed is smaller. For example, when the image ratio of an image to be formed is about 5%, the amount of collected residual toner in the one-to-one copying operation is about three to five times of that in the continuous copying operation. That is, depending upon whether the ratio of one-to-one copying operations is greater or smaller than that of continuous copying operations, the amount of collected residual toner greatly varies.
A powder conveying pump is always driven minimally, considering the above-described variation in the amount of collected residual toner. Therefore, generally, the amount of consumed toner per one picture element is set adjusted to the amount for the one-to-one copying operation, and the powder conveying pump is driven when it is detected the toner consumption amount, which is calculated based upon the integrated value of the number of picture elements, reaches a predetermined value.
Accordingly, when the ratio of continuous copying operations is greater than that of one-to-one copying operations, the time when the powder conveying pump is driven unnecessarily increases. Thereby, airtightness of the powder conveying pump is deteriorated due to abrasion, toner scattering is caused, the life of the powder conveying pump is reduced, and the temperature of the pump rises.
Further, the amount of collected residual toner which is conveyed to a developing device by the powder conveying pump varies due to the deterioration of the airtightness of the powder conveying pump, causing instability to the mixture ratio of the collected residual toner relative to a new toner, and consequently decreasing the image quality.
Furthermore, depending upon the density of a toner image, the amount of collected residual toner per one picture element greatly varies.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above-discussed and other problems and addresses the above-discussed and other problems.
Preferred embodiments of the present invention provide a novel toner recycling device of an electrophotographic image forming apparatus, in which the amount of collected residual toner is precisely detected in accordance of the copying mode so that a driving interval of a powder conveying pump is enlarged and at the same time the ratio of recycled toner in a developer is made constant so that the image quality is improved.
The preferred embodiments of the present invention further provide a novel toner recycling device of an electrophotographic image forming apparatus, in which the amount of collected toner is precisely detected in accordance of the density of a toner image so that a driving interval of a powder conveying pump is enlarged and at the same time the ratio of recycled toner in a developer is made constant so that the image quality is improved.
The preferred embodiments of the present invention also provide a method of precisely detecting the density of a toner image based upon an objective criterion and of precisely detecting the amount of collected residual toner.
Further, the preferred embodiments of the present invention provide a method of avoiding useless driving of a powder conveying pump so that the life of the powder conveying pump is increased.
According to a preferred embodiment of the present invention, a toner recycling device of an electrophotographic image forming apparatus conveys collected used toner to a developing device of the image forming apparatus. The toner recycling device includes a powder conveying pump that is driven to convey the collected used toner to the developing device of the image forming apparatus when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value, and an adding device that adds a predetermined constant value to the integrated value when driving of an image bearing member of the image forming apparatus is detected.
According to another preferred embodiment of the present invention, a toner recycling device of an electrophotographic image forming apparatus to convey collected used toner to a developing device of the image forming apparatus includes a powder conveying pump that is driven to convey the collected used toner to the developing device of the image forming apparatus when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value, and a coefficient determining device that determines a predetermined coefficient according to toner density of a developer of the image forming apparatus and that corrects each of the predetermined numerical values by multiplying the each of the predetermined numerical values by the coefficient.
According to still another preferred embodiment of the present invention, a toner recycling device of an electrophotographic image forming apparatus to convey collected used toner to a developing device of the image forming apparatus includes a powder conveying pump that is driven to convey the collected used toner to the developing device of the image forming apparatus when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value, an adding device that adds a predetermined constant value to the integrated value when driving of an image bearing member of the image forming apparatus is detected, and a coefficient determining device that determines a predetermined coefficient according to toner density of a developer of the image forming apparatus and that corrects each of the predetermined numerical values by multiplying the each of the predetermined numerical values by the coefficient.
In the above-described toner recycling devices, the coefficient may be determined according to a difference between the toner density of the developer and a target value for the toner density. Further, the powder conveying pump may be stopped to be driven a predetermined time after having been started to be driven.
According to still another preferred embodiment of the present invention, an electrophotographic image forming apparatus includes a developing device to develop a latent image formed on a photoconductor with a toner, and a toner recycling device that conveys collected used toner to the developing device. The toner recycling device includes a powder conveying pump that is driven to convey the collected used toner to the developing device when an integrated value of predetermined numerical values, each based upon a number of picture elements of an image to be formed, is equal to or greater than a constant value, and an adding device that adds a predetermined constant value to the integrated value when driving of the photoconductor is detected.
According to still another preferred embodiment of the present invention, an electrophotographic image forming apparatus includes a developing device to develop a latent image formed on a photoconductor with a toner, and a toner recycling device to convey collected used toner to the developing device. The toner recycling device includes a powder conveying pump that is driven to convey the collected used toner to the developing device when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value, and a coefficient determining device that determines a predetermined coefficient according to toner density of a developer of the image forming apparatus and that corrects each of the predetermined numerical values by multiplying the each of the predetermined numerical values by the coefficient.
According to still another preferred embodiment of the present invention, an electrophotographic image forming apparatus includes a developing device to develop a latent image formed on a photoconductor with a toner, and a toner recycling device configured to convey collected used toner to the developing device. The toner recycling device includes a powder conveying pump that is driven to convey the collected used toner to the developing device when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value, an adding device that adds a predetermined constant value to the integrated value when driving of the photoconductor is detected, and a coefficient determining device that determines a predetermined coefficient according to toner density of a developer of the image forming apparatus and that corrects each of the predetermined numerical values by multiplying the each of the predetermined numerical values by the coefficient.
In the above-described electrophotographic image forming apparatuses, the coefficient may be determined according to a difference between the toner density of the developer and a target value for the toner density. Further, the powder conveying pump may be stopped to be driven a predetermined time after having been started to be driven. According to still another preferred embodiment of the present invention, a toner recycling method of an electrophotographic image forming apparatus includes driving a powder conveying pump to convey collected used toner to a developing device of the image forming apparatus when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value, and adding a predetermined constant value to the integrated value when driving of an image bearing member of the image forming apparatus is detected.
According to still another preferred embodiment of the present invention, a toner recycling method of an electrophotographic image forming apparatus includes driving a powder conveying pump to convey collected used toner to a developing device of the image forming apparatus when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value, and determining a predetermined coefficient according to toner density of a developer of the image forming apparatus and correcting each of the predetermined numerical values by multiplying the each of the predetermined numerical values by the coefficient.
According to still another preferred embodiment of the present invention, a toner recycling method of an electrophotographic image forming apparatus includes driving a powder conveying pump to convey collected used toner to a developing device of the image forming apparatus when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value, adding a predetermined constant value to the integrated value when driving of an image bearing member of the image forming apparatus is detected, and determining a predetermined coefficient according to toner density of a developer of the image forming apparatus and correcting each of the predetermined numerical values by multiplying each of the predetermined numerical values by the coefficient.
In the above-described toner recycling methods, in the determining step the coefficient may be determined according to a difference between the toner density of the developer and a target value for the toner density. Further, in the driving step the powder conveying pump may be stopped to be driven a predetermined time after having been started to be driven.
According to still another preferred embodiment of the present invention, an electrophotographic image forming method includes developing a latent image formed on a photoconductor with a toner, and recycling collected used toner to a developing device. The recycling includes driving a powder conveying pump to convey the collected used toner to the developing device when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value, and adding a predetermined constant value to the integrated value when driving of the photoconductor is detected.
According to still another preferred embodiment of the present invention, an electrophotographic image forming method includes developing a latent image formed on a photoconductor with a toner by a developing device, and recycling collected used toner to the developing device. The recycling includes driving a powder conveying pump to convey the collected used toner to the developing device when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value, and determining a predetermined coefficient according to toner density of a developer of the image forming apparatus and correcting each of the predetermined numerical values by multiplying the each of the predetermined numerical values by the coefficient.
According to still another preferred embodiment of the present invention, an electrophotographic image forming method includes developing a latent image formed on a photoconductor with a toner by a developing device, and recycling collected used toner to the developing device. The recycling includes driving a powder conveying pump to convey the collected used toner to the developing device when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value, adding a predetermined constant value to the integrated value when driving of the photoconductor is detected, and determining a predetermined coefficient according to toner density of a developer of the image forming apparatus and for correcting each of the predetermined numerical values by multiplying the each of the predetermined numerical values by the coefficient.
In the above-described image forming methods, in the determining step the coefficient may be determined according to a difference between the toner density of the developer and a target value for the toner density. Further, in the driving step the powder conveying pump may be stopped to be driven a predetermined time after having been started to be driven.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in conjunction with accompanying drawings, wherein:
FIG. 1
is a schematic drawing illustrating a construction of a digital copying machine according to a preferred embodiment of the present invention;
FIG. 2
is a partially enlarged drawing of the digital copying machine of
FIG. 1
, illustrating portions around a photoconductor;
FIG. 3
is a perspective view of a toner recycling device of the digital copying machine;
FIG. 4
is a perspective view illustrating a state that the toner recycling device is set in the digital copying machine;
FIG. 5
is a cross section of the toner recycling device;
FIG. 6
is a flowchart illustrating an exemplary operation of driving the toner recycling device of the digital copying machine; and
FIG. 7
is a setting table used in driving the toner recycling device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, preferred embodiments of the present invention are described.
FIG. 1
illustrates a schematic construction of a digital copying machine according to a preferred embodiment of the present invention. Reference
100
denotes a main body of the digital copying machine. A reading and writing device
200
is mounted on the main body
100
, and the main body
100
is mounted on a sheet feeding device
300
which is shaped like a table.
A drum-like-shaped photoconductor
10
is provided inside the main body
100
. Around the photoconductor
10
provided are a charging device
12
, a developing device
13
, a transfer and conveying device
14
, and a cleaning device
15
in this order in a rotating direction “A” of the photoconductor
10
.
A sheet conveying path “B” is formed in the main body
100
to convey a sheet from right to left in
FIG. 1
, passing between the photoconductor
10
and the transfer and conveying device
14
. A registration roller
16
is provided in the sheet conveying path B upstream of the photoconductor
10
in a sheet conveying direction. A fixing device
17
is provided along the sheet conveying path B downstream of the photoconductor
10
. The fixing device
17
includes a fixing roller
18
having a heater inside and a pressing roller
19
pressed against the fixing roller
18
from below. A discharging roller
20
is arranged left of the fixing device
17
in the figure.
The reading and writing device
200
includes a laser writing device
22
and an original reading device
23
. The laser writing device
22
includes, for scanning, a laser light source (not shown), a rotating multi-faced mirror
24
, a polygon motor
25
, and a scanning optical system including a fθ lens, etc. The original reading device
23
includes a light source
28
, a plurality of mirrors
29
, and an image sensor
30
(e.g., a CCD, etc.).
The main body
100
further includes a contact glass
31
at an upper surface thereof, and an original pressing plate
32
is provided at the upper surface so as to open and close and to cover the contact glass
31
when closed.
The sheet feeding device
300
includes multiple feeding cassettes
34
arranged inside in a multistage manner. Each of the cassettes
34
has a feeding roller
35
and a separating roller
36
. A feeding path “C” is formed right side of the multistage feeding cassettes
34
in the figure to connect to the sheet feeding path B. Feeding rollers
37
are provided in the sheet feeding path C.
A manual feeding tray
38
for guiding a manually fed sheet to the sheet feeding path B is provided at the right side of the main body
100
in the figure so as to freely open and close. A discharging tray
39
is provided at the left side of the main body
100
in the figure to receive a sheet discharged by the discharging roller
20
.
When making a copy of an original document using the above-described digital copying machine, the original document is placed on the contact glass
31
by opening the original pressing plate
32
, and then a start switch (not shown) is depressed.
Then, the original reading device
23
is driven to move the light source
28
along the contact glass
33
. A light from the light source
28
is reflected by the surface of the original document on the contact glass
31
, the reflected light is reflected by the plurality of mirrors
29
so as to be incident onto the image sensor
30
, so that the contents of the original document is read by the image sensor
30
.
At the same time, the photoconductor
10
is driven by a photoconductor driving motor (not shown), the charging device
12
uniformly charges the surface of the photoconductor
10
, and then the laser writing device
22
performs image writing by irradiating a laser light according to the contents of the original document read by the original reading device
23
, and thereby an electrostatic latent image is formed on the surface of the photoconductor
10
. The latent image is visualized by applying toner thereon with the developing device
13
.
When the start switch is depressed, the feeding roller
35
of a selected one of the cassettes
34
is rotated to feed out a sheet from the selected one of the cassettes
34
. The fed sheet is separated from other sheets in the selected one of the cassettes
34
, and is fed into the sheet feeding path C. The sheet is fed by the conveying roller
37
to be guided to the sheet conveying path B, and the sheet is stopped by impinging upon the registration roller
16
. The registration roller
16
is rotated in synchronism with a rotation of the photoconductor
10
so that the sheet is conveyed to a position below the photoconductor
10
.
Alternatively, the feeding roller
41
for the manual feeding tray
38
is rotated to feed a sheet set on the manual feeding tray
38
into the sheet feeding path B. The sheet is also conveyed by the registration roller
16
in synchronism with a rotation of the photoconductor
10
so as to be conveyed to the position below the photoconductor
10
.
Thereafter, a visual image on the photoconductor
10
is electrostatically transferred onto the sheet fed to the position below the photoconductor
10
by the transfer and conveying device
14
. Residual toner on the photoconductor
10
after transfer of the visual image is removed by the cleaning device
15
, so that the photoconductor
10
is cleaned for subsequent image formation which starts with charging by the charging device
12
.
The sheet on which the visual image has been transferred from the photoconductor
10
is conveyed by the transfer and conveying device
14
to the fixing device
14
, where the transferred image is fixed onto the sheet by applying heat and pressure with the fixing roller
18
and the pressing roller
19
. Thereafter, the sheet is discharged onto the discharging tray
39
by the discharging roller
20
to be stacked thereupon.
Now, the developing device
13
is described referring to
FIG. 2
, which is a partially enlarged drawing of FIG.
2
. The developing device
13
includes a developing tank
43
and a developing hopper
44
. The developing tank
43
includes, inside of a developing case
58
, a first developing roller
45
, a second developing roller
46
, a paddle wheel
47
, a stirring roller
48
, a conveying screw
49
, a separator
50
, a doctor blade
51
, and a toner density sensor
52
. A two-component developer including a toner and a developer is accommodated in the developing tank
43
.
The developing hopper
44
includes a toner replenishing member
54
formed in a gear-like shape and a replenishing regulating plate
55
, and an agitator
56
. A toner is accommodated in the developing hopper
44
.
The developing device
13
stirs the two-component developer in the developing case
58
with rotation of the stirring roller
48
so as to be charged by friction. The two-component developer is scooped up by rotation of the paddle wheel
47
, and is attracted to the first developing roller
45
and the second developing roller
46
by magnets provided in the first and second developing rollers
45
and
46
.
The attracted developer is conveyed by sleeves formed at the outer circumferential surfaces of the first and second developing rollers
45
and
46
, and after an excessive portion of the developer is scraped by the doctor blade
51
to be removed, the developer is attracted to the photoconductor
10
by a developing bias, and thereby an electrostatic image on the photoconductor
10
is developed.
In the above-described developing device
13
, when the developer is applied onto the photoconductor
10
and toner of the developer is consumed, the ratio of toner in the developer, i.e. toner density, is decreased. Therefore, when a toner density Vt of the developer is decreased to be below a predetermined value relative to a target value Vref for the toner density, the agitator
56
is rotated to stir the toner in the developing hopper
44
and at the same time the toner is conveyed to the toner replenishing device
54
. The toner replenishing device
54
is rotated to vibrate the replenishing regulating plate
55
, so that the toner is supplied from the developing hopper
44
to the developing tank
43
. Thereby, the toner density of the developer in the developing tank
43
is maintained.
The toner density of the developer is measured by the toner density sensor
52
mounted to the developing case
58
of the developing tank
43
. The target value Vref of the toner density is set based upon a value obtained by measuring a toner image for monitoring which is formed on the photoconductor
10
with a photo-sensor (not shown).
As described above, toner adhered on the photoconductor
10
is electrostatically transferred onto a sheet by the transfer and conveying device
14
. In actuality, however, about 10% of the toner adhered on the photoconductor
10
is not transferred onto the sheet and remains on the photoconductor
10
. The residual toner remaining on the photoconductor
10
is scraped off by a cleaning blade
60
and a brush roller
61
of the cleaning device
15
.
The toner scraped off the photoconductor
10
by the cleaning device
15
is put into a collecting tank
62
of the cleaning device
15
. The toner is then conveyed by a collecting screw
63
to one side of the cleaning device
15
in the axial direction of the photoconductor
10
. The toner is then discharged, as illustrated in
FIG. 3
, from a discharging outlet
64
of the cleaning device
15
to be guided to a toner recycling device
66
.
The toner recycling device
66
includes, as illustrated in
FIGS. 3
,
4
, and
5
, a toner guiding part
68
which is formed to protrude from a case
67
toward above. A tip end portion of the toner guiding part
68
is connected with the discharging outlet
64
of the cleaning device
15
, so that collected toner discharged from the discharging outlet
64
falls down by gravity inside of the case
67
.
The case
67
is sealed by a sealing member
69
(FIG.
5
), and a lateral conveying screw
71
is provided inside of the case
67
so as to be supported by a bearing
70
in a freely rotatable manner. A timing pulley
73
is mounted to one end of the lateral conveying screw
71
via a clutch
72
. A timing belt
74
is spanned around the timing pulley
73
. The clutch
72
is turned on and off by a MPU (microprocessor unit)
75
.
A powder conveying pump
77
, which is called a Monau pump, is mounted to the case
67
. The powder conveying pump
77
includes a holder
78
in which a stator
79
is fixed, and a rotor
80
is provided so as to enclose the stator
79
. The rotor
80
is connected with the lateral conveying screw
71
.
The holder
78
is connected with one end of an air tube
81
, and the other end of the air tube
81
is connected with an air pump
82
. The air pump
81
is turned and off by the MPU
75
.
A discharging outlet
83
of the powder conveying pump
77
is connected with one end of a conveying tube
84
, and the other end of the conveying tube
84
is connected with the developing tank
43
of the developing device
13
.
The MPU
75
includes a powder conveying pump driving device “L” which drives the powder conveying pump
77
when the integrated value of predetermined values, each according to the number of picture elements (e.g., the number of picture elements itself, the amount of consumed toner calculated based upon t he number of picture elements or the amount of collected toner, etc.), exceeds a predetermined value, an adding device “M” which adds a predetermined value to the integrated value when driving of an image bearing member driving device (i.e., a photoconductor driving motor for driving the photoconductor
10
, etc.) is detected, and a coefficient determining device “N” which determines a predetermined coefficient “n” according to toner density of the developer and which corrects each of the predetermined values by multiplying the each of the predetermined values by the coefficient n.
Next, an exemplary operation of driving the toner recycling device
66
is described referring to a flowchart illustrated in FIG.
6
.
When a copying operation is started by depression of the start switch (not shown), in step S
1
, the number of picture elements of a formed image is counted, and a toner consumption amount “a” is calculated based on the counted number of picture elements. At the same time, when driving of the photoconductor driving motor (not shown) which drives the photoconductor
10
is detected, the adding device M adds a predetermined value “b” (e.g., 60 mg) to an integrated value “c” of the toner consumption amounts prior to that particular copying operation.
In step S
2
, the coefficient determining device N determines a predetermined coefficient “n” according to the toner density of a developer. For example, a difference between the toner density Vt of the developer and a target value Vref for the toner density is obtained, and based on the difference, using a setting table illustrated in
FIG. 7
, the coefficient “n” is determined. The toner consumption amount “a” is then corrected by multiplying the toner consumption amount “a” by the coefficient “n”. The corrected toner consumption amount “a” is added to the integrated value “c” of the toner consumption amounts so that a new integrated value “x” of the toner consumption amounts is obtained.
In step S
3
, it is determined if the integrated value “x” is equal to or greater than a predetermined value “d” (e.g., 3000 mg). When the integrated value “x” is smaller than the predetermined value “d”, the process proceeds to step S
4
. In step S
4
, if a next copying operation exists, the process returns to step S
2
, and if the next copying operation does not exist, the operation ends.
When the integrated value “x” of the toner consumption amounts is equal to or greater than the predetermined value “d”, the process proceeds to step S
5
, where the powder pump driving device L turns on the clutch
72
and the air pump
82
. The rotation of the timing pulley
73
which is rotated by rotation of the timing belt
74
is conveyed to the lateral conveying screw
71
to rotate the rotor
80
while contacting the stator
79
. Thereby, the collected toner is conveyed in the axial direction of the rotor
80
, is fluidized by the air from the air pump
82
, and is then returned to the developing device
13
through the conveying tube
84
.
In step S
6
, two seconds after the clutch
72
has been turned on, the clutch
72
is turned off. In step S
7
, four seconds after the air pump
82
has been turned on, the air pump
82
is turned off. In step S
8
, the integrated value “x” of the toner consumption amounts is reset.
Thereafter, in step S
9
, if a next copying operation exists, the process returns to step S
2
. If the next copying operation does not exist, the process ends.
As the background soiling of the photoconductor
10
deteriorates, the toner density Vt of the developer tends to increase relative to the target value Vref for the toner density. Accordingly, in the setting table illustrated in
FIG. 7
, as the background soiling of the photoconductor
10
deteriorates, the coefficient “n” increases, so that the driving interval of the powder conveying pump
77
is reduced.
For example, in copying an image of an A4 sheet having the image ratio of 5%, when Vref−Vt=0 and the coefficient “n” is 1, the powder conveying pump
77
is driven once, each time when 34 copies are made in the one-to-one copying operation, when 60 copies are made in the one-two-three copying operation, and when 100 copies are made in the one-to-500 copying operation.
In the digital copying machine of
FIG. 1
, because a transfer belt
90
of the transfer and conveying device
14
also contacts the photoconductor
10
, toner also adheres to the transfer belt
10
. Accordingly, a cleaning device
91
is provided for the transfer and conveying device
14
to scrape off residual toner on the transfer belt
90
.
However, the residual toner scraped off by the transferring and conveying device
14
often contains foreign substance such as paper dust, etc. Accordingly, the residual toner scraped off by the transfer and conveying device
14
is not put into the toner recycling device
66
, and instead, as illustrated in
FIGS. 1
,
3
, and
4
, falls down through a discharging outlet
92
of the cleaning device
91
by gravity to be collected by a discharged toner tank
94
through a discharging tube
93
.
In the above-described embodiment, the description has been made with respect to the drum-like-shaped photoconductor
10
. However, the present invention can be applied to a case in which the photoconductor
10
is belt-like shaped.
Further, in an electrophotographic image forming apparatus in which a toner image on a photoconductor is transferred onto a sheet via an intermediate transfer member, the present invention can be applied to a case in which residual toner on the intermediate transfer belt is collected in addition to collecting of residual toner on the photoconductor.
Numerous additional modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.
Claims
- 1. A toner recycling device of an electrophotographic image forming apparatus to convey collected used toner to a developing device of the image forming apparatus, comprising:a powder conveying pump driven to convey collected used toner to a developing device of the image forming apparatus when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value; and an adding device that adds a predetermined constant value to the integrated value when driving of an image bearing member of the image forming apparatus is detected.
- 2. The toner recycling device of claim 1,wherein the powder conveying pump is stopped to be driven a predetermined time after having been started to be driven.
- 3. A toner recycling device of an electrophotographic image forming apparatus to convey collected used toner to a developing device of the image forming apparatus, comprising:a powder conveying pump that is driven to convey the collected used toner to the developing device of the image forming apparatus when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value; and a coefficient determining device that determines a predetermined coefficient according to toner density of a developer of the image forming apparatus and that corrects each of the predetermined numerical values by multiplying the each of the predetermined numerical values by the coefficient.
- 4. The toner recycling device of claim 3,wherein the coefficient is determined according to a difference between the toner density of the developer and a target value for the toner density.
- 5. The toner recycling device of claim 3,wherein the powder conveying pump is stopped to be driven a predetermined time after having been started to be driven.
- 6. A toner recycling device of an electrophotographic image forming apparatus to convey collected used toner to a developing device of the image forming apparatus, comprising:a powder conveying pump that is driven to convey the collected used toner to the developing device of the image forming apparatus when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value; an adding device that adds a predetermined constant value to the integrated value when driving of an image bearing member of the image forming apparatus is detected; and a coefficient determining device that determines a predetermined coefficient according to toner density of a developer of the image forming apparatus and that corrects each of the predetermined numerical values by multiplying the each of the predetermined numerical values by the coefficient.
- 7. The toner recycling device of claim 3,wherein the coefficient is determined according to a difference between the toner density of the developer and a target value for the toner density.
- 8. The toner recycling device of claim 6,wherein the powder conveying pump is stopped to be driven a predetermined time after having been started to be driven.
- 9. An electrophotographic image forming apparatus, comprising:a developing device to develop a latent image formed on a photoconductor with a toner; and a toner recycling device that conveys collected used toner to the developing device, the toner recycling device including, a powder conveying pump that is driven to convey the collected used toner to the developing device when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value; and an adding device that adds a predetermined constant value to the integrated value when driving of the photoconductor is detected.
- 10. The electrophotographic image forming apparatus of claim 9,wherein the powder conveying pump is stopped to be driven a predetermined time after having been started to be driven.
- 11. An electrophotographic image forming apparatus, comprising:a developing device to develop a latent image formed on a photoconductor with a toner; and a toner recycling device to convey collected used toner to the developing device, the toner recycling device including, a powder conveying pump that is driven to convey the collected used toner to the developing device when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value; and a coefficient determining device that determines a predetermined coefficient according to toner density of a developer of the image forming apparatus and that corrects each of the predetermined numerical values by multiplying the each of the predetermined numerical values by the predetermined coefficient.
- 12. The electrophotographic image forming apparatus of claim 11,wherein the predetermined coefficient is determined according to a difference between the toner density of the developer and a target value for the toner density.
- 13. The electrophotographic image forming apparatus of claim 11,wherein the powder conveying pump is stopped to be driven a predetermined time after having been started to be driven.
- 14. An electrophotographic image forming apparatus, comprising:a developing device to develop a latent image formed on a photoconductor with a toner; and a toner recycling device configured to convey collected used toner to the developing device, the toner recycling device including, a powder conveying pump that is driven to convey the collected used toner to the developing device when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value; an adding device that adds a predetermined constant value to the integrated value when driving of the photoconductor is detected; and a coefficient determining device that determines a predetermined coefficient according to toner density of a developer of the image forming apparatus and that corrects each of the predetermined numerical values based on a number of picture elements by multiplying the each of the predetermined numerical values by the predetermined coefficient.
- 15. The electrophotographic image forming apparatus of claim 14,wherein the predetermined coefficient is determined according to a difference between the toner density of the developer and a target value for the toner density.
- 16. The electrophotographic image forming apparatus of claim 14,wherein the powder conveying pump is stopped to be driven a predetermined time after having been started to be driven.
- 17. A toner recycling device of an electrophotographic image forming apparatus to convey collected used toner to a developing device of the image forming apparatus, comprising:means for conveying the collected used toner to the developing device of the image forming apparatus when an integrated value of predetermined numerical values, each based on a number of picture elements, is equal to or greater than a constant value; and means for adding a predetermined constant value to the integrated value when driving of an image bearing member of the image forming apparatus is detected.
- 18. A toner recycling device of an electrophotographic image forming apparatus to convey collected used toner to a developing device of the image forming apparatus, comprising:means for conveying the collected used toner to the developing device of the image forming apparatus when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value; and means for determining a predetermined coefficient according to toner density of a developer of the image forming apparatus and for correcting each of the predetermined numerical values by multiplying each of the predetermined numerical values by the predetermined coefficient.
- 19. A toner recycling device of an electrophotographic image forming apparatus to convey collected used toner to a developing device of the image forming apparatus, comprising:means for conveying the collected used toner to the developing device of the image forming apparatus when an integrated value of numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value; means for adding a predetermined constant value to the integrated value when driving of an image bearing member of the image forming apparatus is detected; and means for determining a predetermined coefficient according to toner density of a developer of the image forming apparatus and for correcting each of the predetermined numerical values by multiplying the each of the predetermined numerical values by the predetermined coefficient.
- 20. An electrophotographic image forming apparatus, comprising:means for developing a latent image formed on a photoconductor with a toner; and means for recycling collected used toner to the developing means, the recycling means including, means for conveying the collected used toner to the developing means when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value; and means for adding a predetermined constant value to the integrated value when driving of the photoconductor is detected.
- 21. An electrophotographic image forming apparatus, comprising:means for developing a latent image formed on a photoconductor with a toner; and means for recycling collected used toner to the developing means, the recycling means including, means for conveying the collected used toner to the developing means when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value; and means for determining a predetermined coefficient according to toner density of a developer of the image forming apparatus and for correcting each of the predetermined numerical values by multiplying the each of the predetermined values by the coefficient.
- 22. An electrophotographic image forming apparatus, comprising:means for developing a latent image formed on a photoconductor with a toner; and means for recycling collected used toner to the developing means, the recycling means including, means for conveying the collected used toner to the developing means when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value; means for adding a predetermined constant value to the integrated value when driving of the photoconductor is detected; and means for determining a predetermined coefficient according to toner density of a developer of the image forming apparatus and for correcting each of the predetermined numerical values by multiplying the each of the predetermined numerical values by the coefficient.
- 23. A toner recycling method of an electrophotographic image forming apparatus, comprising the steps of:driving a powder conveying pump to convey collected used toner to a developing device of the image forming apparatus when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value; and adding a predetermined constant value to the integrated value when driving of an image bearing member of the image forming apparatus is detected.
- 24. The toner recycling method of claim 23,wherein, in the driving step the powder conveying pump is stopped to be driven a predetermined time after having been started to be driven.
- 25. A toner recycling method of an electrophotographic image forming apparatus, comprising the steps of:driving a powder conveying pump to convey collected used toner to a developing device of the image forming apparatus when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value; and determining a predetermined coefficient according to toner density of a developer of the image forming apparatus and correcting each of the predetermined numerical values by multiplying the each of the predetermined numerical values by the coefficient.
- 26. The toner recycling method of claim 25,wherein, in the determining step the coefficient is determined according to a difference between the toner density of the developer and a target value for the toner density.
- 27. The toner recycling method of claim 25,wherein, in the driving step the powder conveying pump is stopped to be driven a predetermined time after having been started to be driven.
- 28. A toner recycling method of an electrophotographic image forming apparatus, comprising the steps of:driving a powder conveying pump to convey collected used toner to a developing device of the image forming apparatus when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value; adding a predetermined constant value to the integrated value when driving of an image bearing member of the image forming apparatus is detected; and determining a predetermined coefficient according to toner density of a developer of the image forming apparatus and correcting each of the predetermined numerical values by multiplying each of the predetermined numerical values by the coefficient.
- 29. The toner recycling method of claim 28,wherein, in the determining step the coefficient is determined according to a difference between the toner density of the developer and a target value for the toner density.
- 30. The toner recycling method of claim 28,wherein, in the driving step the powder conveying pump is stopped to be driven a predetermined time after having been started to be driven.
- 31. An electrophotographic image forming method, comprising the steps of:developing a latent image formed on a photoconductor with a toner; and recycling collected used toner to a developing device, the recycling including, driving a powder conveying pump to convey the collected used toner to the developing device when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value; and adding a predetermined constant value to the integrated value when driving of the photoconductor is detected.
- 32. The electrophotographic image forming method of claim 31,wherein, in the driving step the powder conveying pump is stopped to be driven a predetermined time after having been started to be driven.
- 33. An electrophotographic image forming method, comprising:developing a latent image formed on a photoconductor with a toner by a developing device; and recycling collected used toner to the developing device, the recycling including, driving a powder conveying pump to convey the collected used toner to the developing device when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value; and determining a predetermined coefficient according to toner density of a developer of the image forming apparatus and correcting each of the predetermined numerical values by multiplying the each of the predetermined numerical values by the predetermined coefficient.
- 34. The electrophotographic image forming method of claim 33,wherein in the determining step the coefficient is determined according to a difference between the toner density of the developer and a target value for the toner density.
- 35. The electrophotographic image forming method of claim 33,wherein, in the driving step the powder conveying pump is stopped to be driven a predetermined time after having been started to be driven.
- 36. An electrophotographic image forming method, comprising:developing a latent image formed on a photoconductor with a toner by a developing device; and recycling collected used toner to the developing device, the recycling including, driving a powder conveying pump to convey the collected used toner to the developing device when an integrated value of predetermined numerical values, each based on a number of picture elements of an image to be formed, is equal to or greater than a constant value; adding a predetermined constant value to the integrated value when driving of the photoconductor is detected; and determining a predetermined coefficient according to toner density of a developer of the image forming apparatus and for correcting each of the predetermined numerical values by multiplying the each of the predetermined numerical values by the predetermined coefficient.
- 37. The electrophotographic image forming method of claim 36,wherein in the determining step the coefficient is determined according to a difference between the toner density of the developer and a target value for the toner density.
- 38. The electrophotographic image forming method of claim 36,wherein, in the driving step the powder conveying pump is stopped to be driven a predetermined time after having been started to be driven.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2000-367433 |
Dec 2000 |
JP |
|
Foreign Referenced Citations (3)
Number |
Date |
Country |
10-039610 |
Feb 1998 |
JP |
11-073079 |
Mar 1999 |
JP |
2002-169438 |
Jun 2002 |
JP |