JP2002169352A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of realizing the exchange and the replenishment of consumables at appropriate time and restraining a burden in the purchase of the consumables imposed on a user. SOLUTION: In this image forming device, plural image forming stations Pa, Pb, Pc and Pd including photoreceptor drums 222a to 222d for forming an image are arranged in a device main body 100, and a fixing device 217 is arranged on the downstream side of the stations Pa, Pb, Pc and Pd. The stations Pa, Pb, Pc and Pd are constituted as image forming units which can be attached to/detached from the main body 100, and the unit Pd adjacent to the fixing device out of the image forming units is equipped with an offset preventing agent supply part 230 to supply offset preventing agent to the fixing device 217.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a plurality of image forming means arranged in parallel and a fixing device for fixing an image formed by each image forming means.

[0002]

2. Description of the Related Art Generally, an image forming apparatus capable of forming a color image is capable of forming not only a color image but also a black-and-white image, so that the operation rate of the apparatus can be improved. Further, when a color image is formed, the amount of the developer formed on the transfer material on which the image is formed becomes larger than when a black and white image is formed, and the color image is fixed on the transfer material. phenomenon developer adheres fixing device (fixing roller) is generated when. Therefore Conventionally, fixing roller so that never developer to the fixing roller by supplying offset preventing agent (silicone oil) is attached (e.g., see JP-A-57-182768).

[0003]

However, as described above, the means for supplying an anti-offset agent such as silicone oil to the fixing roller does not allow the developer to adhere to the fixing roller when the anti-offset agent is no longer supplied. As a result, the developer adhering to the subsequent transfer material is fixed, leading to contamination of the transfer material and the image. Therefore, regular replenishment is required before the supply of the offset preventive agent becomes insufficient. However, it is troublesome for the user to replace the consumables (offset preventive agent). There is a problem that the cost burden of the user also becomes a heavy burden for the user.

[0004] Therefore, the present invention can easily replace and replenish the offset inhibitor at an appropriate time,
An object of the present invention is to provide an image forming apparatus in which the burden of purchasing consumables for a user is suppressed.

[0005]

In order to solve the above-mentioned problems, the present invention has a plurality of image forming means for forming an image arranged in parallel in a main body of the apparatus, and a fixing device arranged downstream of the image forming means. Wherein the image forming unit is configured as a replacement unit that is detachable from the apparatus main body, and the image forming unit adjacent to the fixing device includes an offset preventing agent for the fixing device. It is characterized by comprising an offset preventing agent supply section for supplying.

According to the present invention, in the image forming apparatus, the image forming means adjacent to the fixing device is an exchange unit for forming a black image.

Further, according to the present invention, in the image forming apparatus, the image forming means adjacent to the fixing device is an exchange unit for forming a color image.

In the present invention having such a configuration, the image forming means is constituted as an exchange unit which is detachable from the apparatus main body, and one of the image forming means adjacent to the fixing device is provided with an offset preventing agent. Since the offset prevention agent supply section is provided, the offset prevention agent supply section can be simultaneously replaced by replacing the image forming means. Therefore, the replacement operation is simplified as compared with the conventional case where the image forming unit and the offset preventing agent are supplied separately. If the offset prevention agent supply unit stores the offset prevention agent by the amount used up to the time of replacement of the image forming means, the consumable unit can be replaced at the same time.

In addition, the image forming means adjacent to the fixing device is a replacement unit for forming a black image, so that the fixing unit can be used in a replacement unit containing consumables such as toner and ink for forming a frequently used black image. And an anti-offset agent supply unit to be installed. Therefore, the unit replacement cycle is shortened, the amount of the anti-offset agent in the anti-offset agent supply unit can be reduced, and the exchange unit can be small.

The image forming means adjacent to the fixing device is a replacement unit for forming a color image, so that the image forming means is fixed to a replacement unit containing consumables such as toner and ink for forming a color image which is rarely used. An anti-offset agent supply unit to the device will be incorporated. Therefore, the frequency of replacement is lower than that of the frequently used black image forming means, resulting in a reduction in cost and a reduction in the burden of purchasing consumables on the user.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic sectional view showing a digital color copying machine as an image forming apparatus according to an embodiment of the present invention. An original platen 11 is provided on the upper surface of the copying machine main body 100.
1 and an operation panel to be described later are provided.
Inside the image reading unit 110 and the image forming unit 210
Is provided.

On the upper surface of the platen 111, the platen 11
1 and a double-sided automatic document feeder (RDAF: Reversing Automatic Document Feeder) with a predetermined positional relationship with respect to the surface of the document table 111.
r) 112 is mounted.

The double-sided automatic document feeder 112 first conveys the document so that one side of the document faces the image reading unit 110 at a predetermined position on the document table 111, and the image reading on this one side is completed. Later, when the other surface is at a predetermined position on the
The document is reversed so as to face the document table 0 and is conveyed toward the document table 111. Then, the two-sided automatic document feeder 112
After reading both sides of an image of one document, the original is discharged, and a double-sided conveyance operation is performed for the next document. The operation of conveying the document and reversing the front and back is controlled in relation to the operation of the entire copying machine.

The image reading section 110 is for reading an image of a document conveyed onto the document table 111 by the automatic double-sided document feeder 112, and reciprocates in parallel along the lower surface of the document table 111. , Second original scanning units 113 and 114, an optical lens 115, and a CCD line sensor 116 as a photoelectric conversion element.

The first scanning unit 113 has an exposure lamp for exposing the surface of the original image and a first mirror for deflecting a reflected light image from the original in a predetermined direction. On the other hand, it reciprocates in parallel at a predetermined scanning speed while maintaining a constant distance. The second scanning unit 114 has a second mirror and a third mirror that further deflect the reflected light image from the document deflected by the first mirror of the first scanning unit 113 in a predetermined direction, It reciprocates in parallel with the first scanning unit 113 while maintaining a constant speed relationship.

The optical lens 115 reduces the reflected light image from the document deflected by the third mirror of the second scanning unit 114 and converts the reduced light image into the CCD line sensor 11.
6, which forms an image at a predetermined position, sequentially photoelectrically converts the formed light image, and outputs it as an electric signal. A monochrome image or a color image is read, and R (red) and G (green) are read.
A three-line color CCD capable of outputting line data that is color-separated into B (blue) color components. The document image information converted into an electric signal by the CCD line sensor 116 is further transferred to an image processing unit described later and subjected to predetermined image data processing.

[0018] Next, the configuration of each unit relating to this and the image forming section 210. Below the image forming unit 210, there is provided a paper feed mechanism 221 that separates sheets (recording media) P stacked and accommodated in a sheet tray one by one and supplies the separated sheets P to the image forming unit 210. And one
The sheets P separated and supplied one by one are conveyed to the image forming unit 210 with the timing controlled by a pair of registration rollers 212 disposed in front of the image forming unit 210. Further, the sheet P on which an image is formed on one side is re-supplied and conveyed to the image forming unit 210 at the timing of image formation by the image forming unit 210 for double-sided printing. The details of the re-supply conveyance will be described later.

[0019] Below the image forming section 210, the conveying belt mechanism 213 is arranged transcribed. The transfer / transport belt mechanism 213 is provided between the drive roller 214 and the driven roller 215 to extend substantially in parallel with the transfer / transport belt 21.
6, the paper P is electrostatically attracted and transported.

A fixing device 217 for fixing the toner image transferred and formed on the paper P to the paper P is disposed downstream of the transfer and transport belt mechanism 213. A pair of fixing rollers 217a and 217b of the fixing device 217
The paper P that has passed through the gap is transferred to the conveyance direction switching gate 218.
After that, the sheet is discharged by a discharge roller 219 onto a discharge tray 220 attached to the outer wall of the copying machine main body 100.

The switching gate 218 is connected to the sheet P after fixing.
Is selectively switched between a path for discharging the paper P to the copying machine main body 100 and a path for re-supplying the paper P to the image forming unit 210. The sheet P is switched transport direction toward the image forming unit 210 again by the switching gate 218, after being reversed through a switch-back conveyance path 221, the image forming unit 21
0 again.

An image forming section 210 is disposed above the transfer and conveyance belt 216 and close to the transfer and conveyance belt 216. The image forming section 210 includes a first image forming station Pa, a second image forming station Pb, and a third image forming station P, which are image forming means.
c and a fourth image forming station Pd, and are arranged side by side in this order from the upstream side of the paper transport path.

The transfer conveyance belt 216 is driven by the driving roller 21.
4, by friction drive in the direction of arrow Z shown in FIG.
The paper P is fed through the paper feeding mechanism 211 as described above carrying the paper P image forming stations Pa, P
b, Pc, and Pd.

Each image station P as an image forming means
a to Pd have substantially the same configuration. Each of the image stations Pa to Pd has a photosensitive drum 222a, 222b, 22 which is driven to rotate in the direction of arrow F shown in FIG.
2c and 222d, respectively. Around the photosensitive drums 222a to 222d, the photosensitive drums 222a
Charger 223a for uniformly charging each ～222D,
223b, 223c, and 223d, photosensitive drum 222
developing devices 224a, 224b, 224c, 224d for developing the electrostatic latent images formed on
And transfer dischargers 225a and 225 for transferring the developed toner images on the photosensitive drums 222a to 222d to the paper P.
5b, 225c, and 225d, and the photosensitive drums 222a to 222d.
Cleaning devices 226a, 226b, 226c, and 226d for removing the toner remaining on 222d are sequentially arranged along the rotation direction of the photosensitive drums 222a to 222d. Each of the image stations Pa to Pd is configured to be detachable from the apparatus main body 100 as an image forming and replacing unit centering on the photosensitive drums 222a to 222d. Then, the consumables such as the photosensitive drums 222a to 222d are replaced with new image forming and replacing units (image stations) together with the life of the consumables.
The quality of the formed image can be maintained.

Above the photosensitive drums 222a to 222d, laser beam scanner units 227a and 227
7b, 227c and 227d are provided respectively.
The laser beam scanner units 227a to 227d are
A polygon mirror (deflecting device) 240 for deflecting a laser beam from a semiconductor laser element (not shown) that emits dot light modulated according to image data in the main scanning direction.
a to 240d and the laser beams deflected by the polygon mirrors 240a to 240d
Fθ lens 241a to form an image on the surface of 222d
241d and mirrors 242a-242d, 243a-
243d and the like (see FIG. 1).

The laser beam scanner 227a receives a pixel signal corresponding to the black component image of the color original image, and the laser beam scanner 227b receives a pixel signal corresponding to the cyan component image of the color original image.
A pixel signal corresponding to the magenta component image of the color original image is input to 7c, and a pixel signal corresponding to the yellow component image of the color original image is input to the laser beam scanner 227d.

As a result, an electrostatic latent image corresponding to the color-converted document image information is formed on each of the photosensitive drums 222a to 222d. The developing device 224a receives the black toner, the developing device 224b receives the cyan toner, the developing device 224c receives the magenta toner, and the developing device 224c.
24d contains yellow toner respectively, and the electrostatic latent images on the photosensitive drums 222a to 222d are:
The image is developed with the toner of each color. As a result, the document image information color-converted by the image forming unit 210 is reproduced as a toner image of each color.

Further, paper attraction charger 228 is provided between the first image forming station Pa and the paper feed mechanism 211, the paper attraction charger 228 charges the surface of the transfer conveyance belt 216 Then, the sheet P supplied from the sheet feeding mechanism 211 is conveyed without shifting between the first image forming station Pa and the fourth image forming station Pd in a state where the sheet P is securely attracted onto the transfer conveying belt 216. .

On the other hand, a static eliminator 229 is provided almost directly above the drive roller 214 between the fourth image station Pd and the fixing device 217. An alternating current is applied to the neutralizer 229 to separate the paper P electrostatically attracted to the transport belt 216 from the transfer transport belt 216.

In the digital color copying machine having the above configuration, cut sheet-shaped paper is used as the paper P. The sheet P is sent out from the sheet cassette and fed to the sheet feeding mechanism 2.
11, the leading end of the sheet P is detected by a sensor (not shown), and based on a detection signal output from the sensor, the pair of registration rollers 212 Once stopped.

The paper P is stored in each image station Pa.
Taking ~Pd and timing sent onto the transfer conveyor belt 216 rotating in the arrow Z direction in FIG. At this time, the transfer conveyor belt 216 is attached to the attraction charger 2 as described above.
Since the predetermined charging is performed by the sheet 28, the sheet P is stably conveyed and supplied while passing through the image stations Pa to Pd.

In each of the image stations Pa to Pd, a toner image of each color is formed, and is superposed on the support surface of the paper P conveyed by being electrostatically attracted and conveyed by the transfer conveyance belt 216. When the transfer of the image by the fourth image station Pd is completed, the sheet P is sequentially separated from the transfer conveyance belt 216 by the charge removing device 229 from the leading end thereof, and is guided to the fixing device 217. Finally, the paper P on which the toner image has been fixed is discharged onto a paper discharge tray 220 from a paper discharge port (not shown).

In the above description, the laser beam is scanned and exposed by the laser beam scanner units 227a to 227d to perform the optical writing on the photosensitive member, but instead of the laser beam scanner unit. Alternatively, a writing optical system (LED head) including a light emitting diode array and an imaging lens array may be used. Since the LED head is smaller in size than the laser beam scanner unit and has no moving parts and is silent, it is suitable for an image forming apparatus such as a tandem type digital color copying machine which requires a plurality of optical writing units. Can be used.

FIG. 2 is an enlarged view of a main part showing the fixing device 217 and the image forming unit 210 adjacent thereto. That is,
A plurality of image forming stations Pa, Pb,
Pc, the most downstream side among Pd, i.e. the fixing device 21
7 between the image forming station Pd and the fixing device 217.
An anti-offset agent supply unit 230 that supplies an anti-offset agent to 7a and 217b is provided.

[0035] Figure 3 is a main part schematic diagram showing a structure of a fixing device 217 and its associated offset preventing agent supply unit 230. As shown in FIGS. 2 and 3, the anti-offset agent supply section 230
a and an offset preventing agent supply pump at one end (not shown)
Supply member 23 composed of a supply pipe having
0b and an anti-offset agent supply port 230c that is provided at the other end of the anti-offset agent supply member 230b and supplies the anti-offset agent to the fixing device 217. On the other hand, in the fixing device 217, a pair of upper fixing rollers 2
17a, lower fixing roller 217b, upper fixing roller 217a
Roller 217c for supplying an anti-offset agent which comes into contact with the surface of the sheet
And an anti-offset agent supply member 217d such as felt for supplying an appropriate amount of anti-offset agent to the anti-offset agent supply roller 217c.

According to the above configuration, the offset preventing agent is supplied from the offset preventing agent tank 230a via the offset preventing agent supplying member 230b.
d, and supplies an appropriate amount of the anti-offset agent from the anti-offset agent supply roller 217c to the surface of the upper fixing roller 217a.

The structures of the offset preventing agent supply section 230 and the fixing device 217 associated therewith are not limited to the above-described structures, but may be the following structures. First, as shown in FIG.
Instead of the offset preventing agent supply member 217d shown in FIG. 3, the sponge roller 21 made of a hygroscopic material is used.
7e is provided. The peripheral surface of the sponge roller 217e is in contact with the anti-offset agent supply roller 217c, and rotates with the frictional force along with the rotation of the anti-offset agent supply roller 217c. It is supplied to the offset prevention agent supply roller 217c.

As shown in FIG. 5, a supply sponge roller 230d made of a hygroscopic material is provided in place of the offset prevention agent supply member 230b and the offset prevention agent supply port 230c shown in FIG. A part of the supply sponge roller 230d is immersed in the offset preventing agent tank 230a. The peripheral surface of the supply sponge roller 230d is in contact with the sponge roller 217e, and is configured to rotate by a frictional force with the rotation of the sponge roller 217e, and to supply the anti-offset agent to the sponge roller 217e. . As described above, the peripheral surface of the sponge roller 217e comes into contact with the offset preventing agent supply roller 217c,
While rotating by the frictional force with the rotation of 7c, the offset preventing agent supplied from the offset preventing agent supply port 230c is supplied to the offset preventing agent supply roller 217c.

As shown in FIG. 6, instead of the supply sponge roller 230d shown in FIG. 5, at least one end is immersed in an offset preventing agent tank 230a.
For example, an anti-offset agent supply member 230g made of felt or the like is provided. The other end is a sponge roller 2
17e, the sponge roller 217 is in contact with the anti-offset agent supply member 230g by the capillary phenomenon.
e is supplied with an anti-offset agent. As mentioned above,
The peripheral surface of the sponge roller 217e abuts against the anti-offset agent supply roller 217c, rotates with frictional force with the rotation of the anti-offset agent supply roller 217c, and offsets the anti-offset agent supplied from the anti-offset agent supply port 230c. It is supplied to the inhibitor supply roller 217c.

As shown in FIG. 7, the sponge roller 217e shown in FIG. 6 may be omitted, and the other end of the offset preventing agent supply member 230g may directly contact the surface of the offset preventing agent supplying roller 217c.

Further, as shown in FIG. 8, an anti-offset tray 217f in which a part of the anti-offset agent supply member 217d can be immersed is provided in the fixing device 217. Valve mechanism 2
An anti-offset tank 230f having 30 g is provided. The valve mechanism 230g includes a cylindrical body 230i and a cylindrical body 23.
0i, a biasing member 230h such as a spring disposed inside
This is a structure including a valve 230j that moves up and down between the lower end of the cylindrical body 230i and the offset tray 217f. One end of the offset prevention agent supply member (felt) 217d is immersed in the offset prevention agent receiving tray 217f, and the other end of the offset prevention agent supply member 217d is in contact with the offset prevention agent supply roller 217c.

When the image forming and replacing unit incorporating the offset preventing agent supply unit is not set in the apparatus main body 100, the valve 230j contacts the lower end of the cylindrical body 230i so as to close the offset preventing agent supply port. (The lock structure is not described in detail). When the image forming exchange unit is set in the apparatus main body 100, the lock is disengaged, the valve by biasing member 230h, such as a spring 23
0j moves downward, the lower end of the valve 230j abuts against the bottom surface of the anti-offset pan 217f, and the cylindrical body 230i
Is open at the lower end. The anti-offset agent is supplied to the anti-offset tray 250 to a predetermined water level from the supply port. When the water level decreases, the offset preventing agent is supplied to a predetermined amount from the gap between the valve 230j and the supply port. Note that the offset preventing agent supply member may not be a planar member, and a columnar member such as a sponge roller 217e may be used.
The peripheral surface may be provided so as to be in contact with the offset preventing agent supply roller 217c.

Note that the above structural examples are not limited to these, and may be combinations of these structures. When the offset preventing agent supply unit 230 is set in the image forming unit 210 together with the image forming station Pd, the fixing is performed. Device 217
Any configuration may be used as long as the offset preventing agent is supplied.

In the above embodiment, the color image forming apparatus in which a plurality of image forming stations are arranged in parallel has been described.
a, Pb, Pc, Pd, the most downstream side, that is,
Image forming station Pd located on fixing device 217 side
In addition, an image forming unit for forming a black image may be arranged. In the description of FIG. 1, the forming unit that forms a black image is the image forming station Pa that is the most upstream, that is, the image forming station Pa that is farthest from the fixing device 217.

[0045] In the color image is an image forming apparatus capable of forming a monochrome mode for forming a monochrome image is relatively well utilized. Therefore, consumables that form black images
(Replacement of replacement unit containing toner, ink, etc.)
Replenishment is performed more frequently than replacement units for color image formation. The fixing unit 21 is attached to an exchange unit for forming a black image whose exchange cycle is short.
By incorporating the anti-offset agent supply unit 7 into the anti-offset agent supply unit 230, the amount of the anti-offset agent stored in the anti-offset agent supply unit 230 can be reduced, and the size of the replacement unit can be relatively reduced. In addition, by incorporating the anti-offset agent supply unit 230 to the fixing device 217 in a replacement unit that is exchanged relatively regularly, the quality of an image formed without the anti-offset agent during operation of the apparatus can be reduced. Compensation can be made so as not to connect.

Further, one of the image forming units for forming a color image can be arranged in the image forming station Pd located on the fixing device 217 side. In the description of FIG. 1, the image forming station Pd for forming a yellow image is located at the most downstream side, that is, near the fixing device 217.

In an image forming apparatus capable of forming a color image and a black and white image, a mode for forming a black and white image is relatively frequently used. Therefore, the replacement frequency of the replacement unit for color image formation depends on the consumables that form the black image.
Replacement of replacement units containing toner (ink, ink, etc.)
This is less than replenishment. Therefore, the fixing device 217 is provided as one of the exchange units for forming a color image.
By incorporating the offset prevention agent supply unit 230 to the
It is longer than the replacement cycle of the replacement unit for forming a black image, and the cost of the replacement unit that is replaced relatively regularly can be minimized. Since this by requiring less expense for the consumable product procurement, it is easy to purchase consumables.

It should be noted that the anti-offset agent supply section 230 provided in the replacement unit stores an amount that almost disappears when the consumables for image formation are replaced. Thereby, at the time of replacement of the replacement unit, also becomes time to replace the offset preventing agent, omitting the waste, it is possible to perform efficient operations

[0049]

As described above in detail, according to the present invention, the image forming means is constituted as an exchange unit which can be attached to and detached from the apparatus main body, and is adjacent to the fixing device in the image forming means. Since the unit is provided with an anti-offset agent supply unit for supplying an anti-offset agent to the fixing device, it is possible to exchange the anti-offset agent at the same time as exchanging consumables in image formation, and the exchange operation is simple and efficient Can be done

Further, according to the present invention, the image forming means adjacent to the fixing device is replaced with a replacement unit for forming a black image.
The anti-offset agent can be exchanged at the same time as the replacement of consumables such as ink, so that the unit replacement cycle is shortened, the amount of the anti-offset agent in the anti-offset agent supply section is small, and the exchange unit can be small .

Further, according to the present invention, the image forming unit adjacent to the fixing device is a replacement unit for forming a color image. The offset preventing agent can be replaced at the same time as the replacement, and the burden on the user to purchase consumables can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a digital color copying machine which is an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part showing a fixing device and an image forming unit adjacent to the fixing device.

FIG. 3 is a schematic view of a main part showing a structure of an offset preventing agent supply unit and a fixing device related thereto.

FIG. 4 is a main part schematic diagram illustrating another structure of an offset preventing agent supply unit and a fixing device related thereto.

5 is a main part schematic view showing another structure of the offset preventing agent supply unit and a fixing device associated with it.

FIG. 6 is a schematic diagram of a main part showing another structure of an offset preventing agent supply unit and a fixing device related thereto.

FIG. 7 is a main part schematic diagram showing the structure of an offset preventing agent supply unit and a fixing device related thereto.

FIG. 8 is a schematic view of a main part showing an offset preventing agent supply unit and a fixing device structure related thereto.

[Explanation of symbols]

 100 Apparatus main body 217 Fixing devices 217a, 217b Fixing roller 217c Offset preventing agent supply roller (coating unit) 217d Felt (coating unit) 217e Sponge roller (coating unit) 222a to 222d Photosensitive drum 230 Offset preventing agent supply unit 230a Offset preventing agent storage Tank Pa, Pb, Pc, Pd Image station

Claims (3)

[Claims] 1. An image forming apparatus in which a plurality of image forming units for forming an image are arranged in parallel in an apparatus main body and a fixing device is arranged downstream of the image forming unit. The image forming unit is configured as an exchange unit that can be attached to and detached from the apparatus main body, and the image forming unit adjacent to the fixing device includes an offset preventing agent supply unit that supplies an offset preventing agent to the fixing device. Image forming apparatus. 2. The image forming apparatus according to claim 1, wherein the image forming unit adjacent to the fixing device is an exchange unit that forms a black image. 3. The image forming apparatus according to claim 1, wherein the image forming unit adjacent to the fixing device is an exchange unit that forms a color image.