JPH07281547A - Color image forming device - Google Patents

Abstract

PURPOSE:To provide a color image forming device capable of efficiently using a cleaning web and oil without making a cost high. CONSTITUTION:An image density sensor 29 is disposed between a press-contact part of a fixing roller 51 and a pressure roller 53 and a transferring means (not shown in a figure), and the density of unfixed toner 40 on a recording paper 41 is detected by the sensor 29. A device system control part 38 decides the driving amount of a solenoid 43 driving the cleaning web 35, and the driving amount of an oil drawing up electromagnetic clutch 44 based on the detected density, drives the clutch 44 so as to supply oil by a specified amount by means of a driving signal (b) before fixing, and cleans a fixing roller 51 by driving the solenoid 43 by the specified amount by means of the driving signal (a) after the fixing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic color image forming apparatus.

[0002]

2. Description of the Related Art Generally, a color image forming apparatus is an example of an apparatus requiring image density control. In this color image forming apparatus, one step is to transfer a recording image formed on a photosensitive drum by charging, exposing, and developing onto a recording paper, and by repeating this step a plurality of times, a plurality of colors are overlaid on the recording paper. A method of forming an image to obtain a color image is used, and it is described in, for example, DSA 2607727 and JP-A-50-50935.

A color image forming apparatus of this type will be described below with reference to FIG. FIG. 6 is a vertical cross-sectional view of this apparatus. As shown in the figure, the photosensitive drum 1 is arranged in the apparatus. The photosensitive drum 1 includes an organic photosensitive member (OP
C), A-Si, CdS, Se or the like is applied to form a photoconductor, and the driving means (not shown) is used to form 100 mm /
It is driven in the direction of the arrow in the figure at a peripheral speed of sec.

Above the photosensitive drum 1, a charging roller 3 is provided.
Are arranged so as to come into contact with each other, and the charging roller 3 has a DC voltage of −700 V and an AC frequency of 700 Hz.
An alternating voltage of pp (peak to peak) -1500V is superposed, and the surface of the photosensitive drum 1 is uniformly charged to approximately -700V.

A laser diode 11 constituting an exposure device, a polygon mirror 13 driven to rotate by a high-speed motor 12, a lens 14, and a folding mirror 15 are arranged above the main body of the apparatus, and a photosensitive drum is provided. 1 is irradiated with light to form an electrostatic latent image of approximately −100V.

Further, on the right side of the photosensitive drum 1, a plurality of developing cartridges 4a, 4b, 4c, 4d are arranged. The developing cartridges 4a, 4b, 4c, 4
d is carried by a rotatable support 9, and the developing openings 5a of the developing cartridges 4a, 4b, 4c, 4d as shown in FIG. 7 are formed on the same cylinder centered on the rotation axis of the support 9. , 5b, 5c, 5d are set.
Each of the developing cartridges 4a, 4b, 4c, 4d is a cartridge in which a toner accommodating portion for accommodating toner of each color and a developing means for developing are integrated into a cartridge, and is detachably attached to the apparatus main body. The toner is replaced when the stored toner is completely consumed.

FIG. 7 shows developing cartridges 4a, 4b, 4
The details of c and 4d are shown. In FIG. 7, the developing cartridges 4a, 4b, 4c and 4d contain yellow toner 4a-1, magenta toner 4b-1, cyan toner 4c-1 and black toner 4d-1, respectively, and a coating roller. 6a, 6b, 6c, 6d, toner regulating members 7a, 7b, 7c, 7d and developing rollers 8a, 8b,
8c and 8d are provided. Therefore, each of the above toners is
The toner is applied onto the developing rollers 8a, 8b, 8c and 8d by the application rollers 6a, 6b, 6c and 6d, and necessary tribo is provided by the toner regulating members 7a, 7b, 7c and 7d. The material of the regulating member is preferably nylon or the like when the toner has a negative polarity and silicone rubber or the like when the toner is positively charged, and is preferably a material that is charged opposite to the polarity of the toner. The peripheral speed of the developing roller 8 is
It is preferable to set the range of 1.0 to 2.0 times the peripheral speed of the photosensitive drum 1. Further, the developing cartridges 4a, 4b, 4c, 4d attached to the support 9 are driven so that the developing openings 5a, 5b, 5c, 5d always face the surface of the photosensitive drum 1 as shown in FIG. As the driving method, for example, the method described in JP-A-50-93437 is used. The developing cartridge eliminates the trouble of toner supply and maintenance and can be easily replaced by a user who does not have special knowledge or skill. Further, as the toner used in the developing cartridge, it is preferable to use a one-component developer, which has a simple cartridge structure, low cost, and easy size reduction, but a two-component developer may be used.

On the other hand, on the left side of the photosensitive drum 1, as shown in FIG. 6, a recording paper (not shown. The same applies hereinafter) is held and the image on the photosensitive drum 1 is recorded on the recording paper. A transfer drum 10 having a function of transferring is arranged. The transfer drum 10 is configured by winding a 2 mm-thick elastic layer 20 around a metal cylinder 19 having a diameter of 156 mm, and further winding a 100 μm-thick PVDF 21 around the elastic layer 20. The transfer drum 10 rotates in the arrow direction at substantially the same speed as the photosensitive drum 1. To do. As the elastic layer, for example, urethane foam made by Inoac is used.

An image density sensor 29 is provided above the transfer drum 10, and several kinds of image density sensors 29 are provided on the transfer drum 10 when the power is turned on by an apparatus system controller (not shown). An image having a standard density is formed, the density is read, and the setting of each parameter is changed to correct the color balance of the apparatus itself.

Further, a fixing device 25 is disposed on the left side of the transfer drum 10, and the fixing device 25 is shown in FIG.
As shown in (1), it is a heat roller fixing type device that allows the recording paper on which the unfixed image is transferred to pass between a pair of rollers including a fixing roller 51 and a pressure roller 53. That is, halogen heaters 52 and 54 are provided inside the fixing roller 51 and the pressure roller 53, respectively, and the temperature is detected by the resistance change of the thermistor (not shown) in contact with the surface of each roller. The temperature of each roller is maintained at a predetermined temperature by controlling the amount of heat generated by the heaters 52 and 54.

In the structure described above, when a signal according to, for example, yellow image information is input to the laser diode 11, the laser light passes through the optical path 16 and the photosensitive drum 1
And an electrostatic latent image is formed on the photosensitive drum 1 at the position where the light is irradiated. The electrostatic latent image moves to a position facing the developing opening of the developing cartridge 4a as the photosensitive drum 1 advances in the arrow direction, and the developing cartridge 4a
Visualized by the yellow toner in a.

On the other hand, in synchronism with the image formation on the photosensitive drum 1, the pickup roller 1 is moved from the recording paper cassette 17 into the pickup roller 1.
The recording paper is fed by 8 and the recording paper is transferred to the transfer drum 1.
It is held at 0 by the gripper 22. Further, the recording material is conveyed to a position facing the photosensitive drum 1 carrying a visualized toner image, and the toner image is formed by a voltage applied between the photosensitive drum 1 and the transfer drum 10 by a power source (not shown). The recording paper is transferred onto the recording paper, and at the same time, the recording paper is attracted to the transfer drum 10 by the charge injection into the recording paper. The recording material may be adsorbed in advance by applying a voltage between the adsorbing roller 23 and the transfer drum 10 as needed.

By carrying out the above steps for magenta, cyan and black toners, toner images of a plurality of colors are formed on the recording paper. The recording paper on which the color image is formed is peeled from the transfer drum 10 by the separation charger 2 and the separation claw 24, and is conveyed to the fixing device 25. As a result, the toner images of a plurality of colors on the recording paper are heated and pressed by the fixing roller 51 and the pressure roller 53 to be fused and fixed,
A color image is formed on the recording paper.

The transfer residual toner on the photosensitive drum 1 is cleaned by a cleaning device 26 such as a known fur brush 28 and blade means. Further, the toner on the transfer drum 10 is also cleaned by the fur brush 28 and the transfer drum cleaning device 27 as necessary, and the transfer drum 1
Fur brush 28 even after the image density control on 0 is performed.
And a transfer drum cleaning device 27.

Further, the fixing roller 5 in the fixing device 25
1. Since the molten toner adheres to the surface of the roller 1 and the pressure roller 53, a coating having a releasing property for the molten toner is applied to the surface of each roller, and a releasing agent such as silicone oil is applied to the surface of each roller. To prevent offset. That is, as shown in FIG. 8, a coating roller 57 is arranged on the surface of the fixing roller 51 so as to abut and rotate, and the silicone oil in the oil tank 55 is passed through the oil pumping roller 56. It is drawn up and evenly applied by the blade 58 from the upstream side of the fixing roller 51. Further, the cleaning web 35 is disposed above the fixing roller 51 so as to come into contact therewith,
The offset toner accumulated on the oil applied on the peripheral surface of the roller was removed.

Therefore, since the silicone oil on the fixing roller gradually decreases with use of the apparatus and the cleaning web becomes dirty, the silicone oil is supplied and the cleaning web is fed at predetermined intervals. In other words, assuming that the consumption of silicone oil on the fixing roller and the degree of dirt on the cleaning web are in a proportional relationship with the fixing execution time and the number of fixed sheets, a certain amount of the recording paper is considered after considering the type or length of the recording paper. When it is detected that the recording paper has passed through the fixing device, a fixed amount of silicone oil is supplied to the fixing roller and a cleaning web is fed by a fixed amount.

Then, the total length of the cleaning web is previously matched with the life of the roller so that the entire cleaning web is wound up and the life of the roller is exhausted.
Furthermore, the relationship between the time when the entire cleaning web is wound up and the amount of recording paper passing is set in advance, and when it is detected that the amount of recording paper passing reaches a predetermined amount, a new cleaning web and roller are replaced. Was.

However, this replacement is not performed for the cleaning web and the roller alone, and in order to improve the maintainability, the fixing roller, the pressure roller, the silicone oil, the oil tank, the cleaning web, and other members involved in the fixing process are unitized. This was done for the entire fixing device.

[0019]

However, according to the above-mentioned conventional example, after detecting the completion of the winding of the cleaning web wound from one shaft to the other shaft, the fixing device replacement cycle is performed. When it is carried out, the winding cycle is constant for each number of passed sheets regardless of the formed image, so that there is the following problem.

That is, in the color image forming apparatus,
Since the offset property varies depending on the formed image such as a color image, a monochromatic image, a solid image, or a halftone image, or the fixing temperature, if the winding cycle is set to correspond to the worst condition, for example, monochromatic half When it is used in an application in which a tone image is formed relatively often, it may have to be replaced before the average life of the fixing device is reached.

On the other hand, a method has been proposed in which pre-formed image data is calculated by the storage means and the supply amount of the cleaning web and the oil supply amount are controlled according to the integrated amount. A huge amount of memory is consumed to calculate the ratio, resulting in an extra cost increase.

An object of the first invention of the present application is to solve the above problems and provide a color image forming apparatus capable of efficiently using a cleaning web and oil without increasing the cost. It is in.

The second object of the present invention is to:
An object of the present invention is to provide a color image forming apparatus which can solve the above-mentioned problems and can replace the cleaning web and the oil with the fixing device at the same time.

[0024]

According to the first invention of the present application, the above object is to provide an unfixed image forming means for forming an unfixed image of color or monochrome, and the unfixed image as a recording material. Transfer means for transferring, a fixing roller and a pressure roller arranged in pressure contact with each other and rotatably arranged,
A releasing agent applying means for applying a releasing agent to both or one of the fixing roller and the pressure roller, and one shaft provided so as to be in sliding contact with both or one of the surfaces of the fixing roller and the pressure roller. In a color image forming apparatus equipped with a cleaning means wound around the other shaft, the density of an unfixed image is arranged in a recording material conveying path from the transfer means to the pressure contact portion of the fixing roller and the pressure roller. And a control set to adjust the coating amount of the release agent by the release agent coating unit and the winding amount of the cleaning unit according to the concentration information detected by the concentration detection unit. Means and means.

According to the second invention of the present application,
The purpose is to set the winding completion time on the other shaft of the cleaning means and the completion time of the release agent application of the release agent applying means to coincide with the pre-estimated fixing roller replacement time, The fixing roller and the pressure roller, and the releasing agent applying means and the cleaning means are arranged as a single fixing device in an exchangeable manner, and the completion of winding of the cleaning means and the completion of applying the releasing agent of the releasing agent applying means are detected. Means to do
And a means for indicating that it is time to replace the fixing device when the completion of winding and coating is detected by the means.

[0026]

According to the color image forming apparatus to which the first invention of the present application is applied, when a color or monochrome unfixed image is formed by the unfixed image forming means, the unfixed image is transferred by the transfer means. It is transferred onto the recording material.
Then, the recording material is conveyed to the pressure contact portion between the fixing roller and the pressure roller, and at this time, the image density thereof is detected by the density detecting means before entering the pressure contact portion.
This density information is transmitted to the control means, and the control means sets the application amount of the release agent by the release agent application means and the winding amount by the cleaning means to appropriate values based on the image density. This is because the offset property differs depending on the concentration. Therefore, good fixing is performed by the fixing roller or the fixing roller and the pressure roller to which an appropriate amount of the release agent is applied according to the density, and further, the fixing roller after fixing or the fixing roller and the pressure roller is contaminated. Is reliably removed by a cleaning means that is wound up in an appropriate amount. Further, since the coating amount and the winding amount of these release agents can be suppressed to the necessary minimum, they can be used efficiently.

According to the second invention of the present application,
In the same manner as the above-mentioned first invention, when an appropriate amount of the cleaning means is wound up, and an appropriate amount of the release agent is applied by the release agent applying means, and the winding and application are finally completed appropriately. In the figure, the detection means detects the completion of the winding and coating, and further, the predetermined means indicates that it is time to replace the fixing device. Therefore, if the fixing device is replaced according to the instruction, the fixing roller and the pressure roller, the release agent applying means, and the cleaning means, which are integrally and replaceably arranged, are replaced.

[0028]

Embodiments 1 to 7 of the present invention will be described with reference to the drawings.

<Embodiment 1> First, Embodiment 1 of the present invention will be described with reference to FIGS. In FIG. 1, reference numeral 38 denotes an apparatus system control unit, which detects a sensor necessary for image formation, controls an actuator, and has an internal ROM.
38a, the sequence control based on the RAM 38b, the density level of the unfixed formed image based on the image density sensor, and the calculation of the sampled density data are performed. An image density sensor 29 detects the image density of the unfixed toner 40 transferred onto the recording paper 41.

A fixing unit 42 is provided with a fixing roller 51 and a pressure roller 53 which rotate while being in pressure contact with each other. Further, a cleaning web 35 is arranged above the fixing roller 51, and the offset toner is wiped off from the fixing roller 51. When the web feed solenoid 43 is driven, the cleaning web 35 is configured to be uniformly rotated and wound only in the A direction by a one-way mechanical mechanism.
The web feed solenoid 43 is used by the device system control unit 3
It is adapted to be driven by a drive signal a from 8.

Reference numeral 44 is an oil pumping electromagnetic clutch for conveying silicone oil to the fixing roller to prevent the transferred unfixed toner from being offset, and is driven by a drive signal b from the apparatus system control unit 38. As a result, the silicone oil collected in the oil sump 46 is pumped up and the oil is supplied to the fixing roller.

A paper discharge sensor 47 detects whether or not the paper is discharged, and also detects whether or not the fixing process is performed and the conveyance is normally performed. Reference numeral 48 is a cleaning web remaining amount detection sensor, and the sensor 48 is lightly pressed against the web. Therefore, the completion of winding can be detected by changing the tension position of the web supply roller at the final end of the web. Four
An oil remaining amount sensor 9 detects that the oil sump 46 has run out of silicone oil. Each of the above sensors 4
Reference numerals 7, 48 and 49 include photosensors and the like.

An external device 50 such as a host computer performs mutual communication with the device system control unit 38.

The operation of the first embodiment of the present invention will be described below with reference to the flowchart of FIG. First, recording paper is fed based on a print signal from an external device, and when the leading edge of the recording paper passes a leading edge sensor (not shown), the latent image is printed on the photosensitive drum based on the image data from the external device. Form an image. Next, by applying a developing bias, the latent image is visualized by the toner flying to form a toner image,
The formed toner image is transferred to recording paper. Then, when this recording paper comes to the position of the image density sensor 29, detection of the density of the toner image transferred onto the recording paper is started (S).
1). This toner development detection sample is applied to several points on the recording paper. When the data output from the image density sensor 29 is sent to the system control unit 38, the system control unit 38 calculates the average value of the sampled density data, and then winds the cleaning web from the calculated density data. A table for referencing the drive amount of the solenoid 43 for taking out is read out from the ROM (S
2). FIG. 3 shows an example of the feed amount of the cleaning web required for the detected average image density value. After the web feed amount is set as described above, after the fixing process is performed, the paper discharge sensor 47 detects whether or not the paper is normally conveyed (S3). That is, when the start of paper discharge is detected and the timer is set (S4 to S5) and it is detected that the recording paper is at the position of the paper discharge sensor 47 for a specified time or longer, it is determined that a jam occurs and the abnormal state processing routine is entered. (S6 to S7). On the other hand, if the paper discharge is completed normally,
The drive signal b for outputting the cleaning web referred to above is output, the cleaning web feed solenoid 43 is driven by a required amount, and the process is terminated (S8).

As described above, according to the present invention, the cleaning web can be used efficiently.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIGS. The same parts as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the first embodiment, the winding control of the cleaning web is performed after the image density is detected, but in the present embodiment, the oil control is performed. The operation will be described with reference to FIG. First, the presence / absence of oil is checked by the oil remaining amount sensor 49 (S11), and if there is no oil, the process proceeds to an oil exchange processing routine informing the external device 50 that there is no oil or prompting the exchange of the oil container 39 (S12). ). On the other hand, if there is oil, it is determined whether the type of image formation is full color or monochrome (S13), and the image forming process is performed for each (S16, S14 to S1).
5) In the full-color mode and the single-color continuous mode, the density is detected in the final transfer step, and in the normal single-color mode, the density is detected in the transfer step (S17). In other words, the image density sensor 29 samples several points of density data in synchronization with the conveyance of the recording paper, and the apparatus system control unit 38 calculates the average density. Then, the oil pumping electromagnetic clutch 4 for determining the oil supply amount based on the calculated average concentration data.
The control amount of the drive signal a of No. 4 is referred to from the reference table shown in FIG. 5 (S18), the oil pumping electromagnetic clutch 44 is driven by the referred control amount (S19), and the fixing process is started.

As described above, according to the present invention, oil can be used efficiently.

Further, the length of the cleaning web 35 and the amount of oil are set so that the winding is completed and the oil application is completed when the fixing device reaches the end of its life. When the completion of the winding and coating is detected by the sensor 48 and the remaining oil amount detection sensor 49, it is displayed on the external device 50 such as the host computer, so that the time for replacing the web and the oil and the fixing device. The replacement times can be matched.

[0040]

As described above, the first aspect of the present application
According to the invention, by detecting the density of the unfixed image and controlling the winding amount of the cleaning web means and the supply amount of the release agent according to the image density, a flexible fixing process can be performed and the efficiency can be improved. Since a good fixing unit can be used, it is possible to reduce variations in device life of the unit due to deviation of the formed image.

According to the second invention of the present application,
When the winding completion time of the cleaning device and the release agent application completion time of the release agent applying device are matched with the life of the fixing device, and when the completion of the winding operation and the completion of the application are detected,
By providing the means for notifying it, it is possible not only to make the replacement time of the cleaning means and the release agent application means coincide with the replacement time of the fixing device, but also

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a device according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing cleaning means winding control in the apparatus of FIG.

FIG. 3 is a diagram showing a relationship between an image density used in the apparatus of FIG. 1 and a winding amount of a cleaning unit.

FIG. 4 is a flow chart showing a release agent application amount control by a release agent application means in Embodiment 2 of the present invention.

FIG. 5 is a diagram showing the relationship between the image density used in Example 2 of the present invention and the winding amount of the cleaning unit.

FIG. 6 is a diagram showing a schematic configuration of a conventional color image forming apparatus.

7 is a diagram showing a schematic configuration of a developing cartridge in the apparatus shown in FIG.

FIG. 8 is a diagram showing a schematic configuration of a fixing device in the device of FIG.

[Explanation of symbols]

1 photosensitive drum (unfixed image forming means) 3 charging roller (unfixed image forming means) 4a, 4b, 4c, 4d developing cartridge (unfixed image forming means) 10 transfer drum (transfer means) 11 laser diode (unfixed image) Forming means) 12 High-speed motor (unfixed image forming means) 13 Polyhedral mirror (unfixed image forming means) 14 Lens (unfixed image forming means) 15 Folding mirror (unfixed image forming means) 29 Image density sensor (density detecting means) ) 35 cleaning web (cleaning means) 38 apparatus system control section (control means) 40 unfixed toner (unfixed image) 41 recording paper (recording material) 48 web remaining amount detection sensor (detection of completion of winding of cleaning means) Means) 49 Oil remaining amount detection sensor (Means for detecting completion of oil application) 51 Fixing roller 5 3 pressure roller

Claims (2)

[Claims] 1. An unfixed image forming means for forming a color or monochrome unfixed image, a transfer means for transferring the unfixed image onto a recording material, a fixing roller rotatably arranged in pressure contact with each other. A pressure roller, a release agent applying unit for applying a release agent to both or one of the fixing roller and the pressure roller, and a release roller disposed so as to be in sliding contact with the surface of both or one of the fixing roller and the pressure roller. In a color image forming apparatus provided with a cleaning unit that is wound up from one shaft to the other shaft, the color image forming apparatus is disposed in a recording material conveyance path from the transfer unit to the pressure contact portion of the fixing roller and the pressure roller, A density detecting means for detecting the density of the unfixed image, and an amount of the release agent applied by the release agent applying means and a cleaning means according to the density information detected by the density detecting means. A color image forming apparatus, comprising: a control unit set to adjust a winding amount. 2. The completion time of winding on the other shaft of the cleaning means and the completion time of application of the release agent of the release agent application means are set so as to coincide with the estimated replacement time of the fixing roller. , The fixing roller and the pressure roller, and the releasing agent applying means and the cleaning means are arranged as an integral fixing device so as to be exchangeable, and the winding of the cleaning means and the application of the releasing agent of the releasing agent applying means are completed. The color image forming apparatus according to claim 1, further comprising: a detecting unit and a unit that indicates that it is time to replace the fixing device when the completion of winding and coating is detected by the unit.