JP4105837B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile machine, or a composite machine thereof, and more particularly, a plurality of toner images sequentially formed on an image carrier are sequentially superimposed on an intermediate transfer body. In particular, the present invention relates to an image forming apparatus that forms an image by collectively transferring a superposed toner image that has been primarily transferred to a transfer target body.
[0002]
[Prior art]
Conventionally, in an electrophotographic copying-type image forming apparatus, a plurality of visible color development images sequentially formed on an image carrier are sequentially primary-transferred on an intermediate transfer body that is moved endlessly. 2. Description of the Related Art An intermediate transfer type image forming apparatus that performs secondary transfer of a primary transfer image collectively onto a transfer sheet of a transfer medium is known.
In recent years, such an image forming apparatus using an intermediate transfer method is advantageous in that it is relatively small in size and has relatively few restrictions on the type of transfer paper that is a transfer target onto which a toner image is finally transferred. In particular, it is used as a color image forming apparatus for forming a full color image.
In such a color image forming apparatus, a toner image constituting a color developed image is transferred as a final image medium as a final image medium due to local transfer omission at the time of primary transfer and secondary transfer. In a paper image, a so-called bug-eating portion where no toner is locally transferred may be generated.
Further, in the case of a line image, transfer omission occurs so that the line is interrupted. Such an abnormal image is likely to occur when a four-color full-color image is formed.
This is because the toner layer becomes thick and the primary transfer is repeated up to four times. Therefore, the mechanical pressure is non-Coulomb due to the contact pressure between the surface of the image carrier and the toner and between the surface of the intermediate transfer body and the toner. This is due to the strong adhesion.
Another reason is that in the process of repeatedly executing the image forming process, a filming phenomenon occurs in which the toner adheres to the surface of the intermediate transfer member in the form of a film, and the adhesion between the surface of the intermediate transfer member and the toner increases. .
Therefore, in order to avoid the occurrence of such worm-eating images, a lubricant is applied to the surfaces of the image carrier and the intermediate transfer member to reduce the adhesion force of the toner, or to reduce the adhesion force of the toner itself. An apparatus to which an improvement such as a reduction is added is put on the market and is known.
It is also known to improve the transferability and prevent the occurrence of abnormal images such as worm-eating by adjusting the relative balance between the toner adhesion force of the image carrier and the toner adhesion force of the intermediate transfer member (special feature). (See the publication of Kaihei 8-21755).
That is, normally, when the toner adhesion force of the image carrier exceeds the toner adhesion force of the intermediate transfer member, it is difficult to transfer the toner from the image carrier to the intermediate transfer member, or the toner transferred onto the intermediate transfer member does not move. A phenomenon such as reverse transfer on the image carrier occurs, and an abnormal image such as a worm-eaten shape is likely to occur. In consideration of such a phenomenon, the toner adhesion force of the image bearing member is made smaller than the toner adhesion force of the intermediate transfer member.
[0003]
Specifically, each surface tension or surface energy of the image carrier and the intermediate transfer member is regarded as a physical quantity representing the ease of adhesion of the toner to each, and the surface tension or surface energy of the image carrier ≦ the surface of the intermediate transfer member By satisfying the condition of force or surface energy, the transferability is improved, and the occurrence of abnormal images such as worm-eating is prevented.
Further, in order to reduce the adhesion force of the toner that gradually increases in the image forming process, a lubricant is applied to the image carrier and the intermediate transfer member during actual use, and the amount of application per unit time is adjusted. It is like that.
As described above, as a countermeasure for preventing the occurrence of an abnormal image such as a worm-eating shape, it is only necessary to be able to control the adhesion force of the toner to the image carrier or the intermediate transfer member. It is effective to apply a lubricant to the transfer body.
FIG. 14 shows a solid image formed by a conventional image forming apparatus. When the toner images on the image bearing member and intermediate transfer member coated with such a lubricant are transferred to a transfer target (P), particularly on a thick or particularly poorly smooth transfer paper, a secondary transfer is performed. Due to the lack of pressure, etc., an abnormal image of a white-out image having a density called “bottle” in a solid image or the like was generated.
Therefore, when transferring to a transfer sheet of a transfer target (P) having a thick or particularly poor smoothness, increasing the pressure of the secondary transfer to compensate for the insufficient pressure of the secondary transfer is a secondary transfer. The load on the drive system is applied to the drive system, and a new abnormal image with color superposition is generated.
Further, a technique for selectively applying a secondary transfer bias for transferring a toner image to a transfer target (P) corresponding to the type of transfer target (P) is also known (Japanese Patent Laid-Open No. 08-286528). See the publication).
As described above, in such a conventional image forming apparatus, the solid lubricant is applied to the solid image or the like transferred from the image bearing member and the intermediate transfer member to which the solid lubricant is applied to the thick or particularly poor smoothness to be transferred. There has been a problem in that a white-out image having a density called “bosoki” is generated.
[0004]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to solve such problems. That is, a white image having a density called “blossiness” on a solid image or the like that is transferred from an image bearing member and an intermediate transfer member coated with a solid lubricant to the surface layer to a thick or particularly unsmoothed transfer target. An object of the present invention is to provide an image forming apparatus that prevents the occurrence.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, an image forming apparatus according to claim 1 collectively collects a plurality of toner images sequentially formed on an image carrier and sequentially superimposing a plurality of toner images on an intermediate transfer member to perform primary transfer. In an image forming apparatus that forms an image by secondary transfer to a transfer object, a rotating image carrier, a first solid lubricant application unit that applies a first solid lubricant to a surface layer of the image carrier, Developing means for forming a toner image on the image carrier having the first solid lubricant applied to the surface by the first solid lubricant application means; an intermediate transfer member that rotates in synchronization with the image carrier; A second solid lubricant applying means for applying a second solid lubricant to the surface layer of the intermediate transfer body, and the intermediate transfer body having the second solid lubricant applied to the surface layer by the second solid lubricant applying means. The first transfer that primarily transfers the toner image Means, second transfer means for secondary transfer of the toner image transferred to the intermediate transfer body by the first transfer means to the transfer target, and transfer target to which the toner image is secondarily transferred by the second transfer means A transfer bias switching unit of the first transfer unit that switches the primary transfer bias of the first transfer unit according to the type of the body. The transfer bias switching unit of the first transfer unit switches the transfer bias of the first transfer unit to be low when the transfer target is thick or the smoothness thereof is lowered. It is characterized by that. The image forming apparatus according to claim 1, wherein the toner image formed by the developing means on the image carrier having the solid lubricant applied to the surface layer by the solid lubricant applying means is applied to the surface layer by the solid lubricant applying means. The toner image transferred by the first transfer unit to the intermediate transfer member that is applied and rotated in synchronization with the image carrier, and the toner image is transferred by the second transfer unit that transfers the toner image to the transfer target. Depending on the type, the transfer bias of the first transfer means is switched by the transfer bias switching means of the first transfer means so that the solid lubricant is transferred from the image carrier and intermediate transfer body coated on the surface layer to the transfer target. It is possible to provide an image forming apparatus that prevents the occurrence of a white-out image having a shading that is referred to as “bottle” in a solid image or the like.
[0006]
Also The toner image formed by the developing means on the image carrier having the solid lubricant applied to the surface layer by the solid lubricant applying means is synchronized with the image carrier by applying the solid lubricant to the surface layer by the solid lubricant applying means. The toner image transferred by the first transfer unit to the intermediate transfer member that rotates and the toner image is transferred by the second transfer unit that transfers the toner image to the transfer target member is thick or smooth. The transfer bias of the first transfer means is switched so that the transfer bias of the first transfer means becomes lower than the normal transfer bias due to a decrease in the thickness or smoothness of the transfer paper. Occurrence of a white-out image having a density called “blossiness” on a solid image or the like that is transferred from an image bearing member and an intermediate transfer member to which a lubricant is applied to the surface layer to a transfer target that is thick or has particularly poor smoothness It is to be able to provide an image forming apparatus to prevent. Claim 2 The transfer bias switching means of the first transfer means according to the present invention is an image forming apparatus comprising a transfer object type input means for inputting the type of transfer object onto which the toner image is transferred by the second transfer means. Special It is a sign. Claim 2 According to the present invention, a toner image formed by a developing unit is applied to an image carrier having a solid lubricant applied to a surface layer by a solid lubricant applying unit, and an image carrier having a solid lubricant applied to the surface layer by a solid lubricant applying unit. The toner image transferred by the first transfer unit is transferred to the intermediate transfer member that rotates in synchronization with the second transfer unit that transfers the toner image to the transfer target member. The transfer bias of the first transfer unit is switched by the transfer bias switching unit of the first transfer unit in accordance with the input from the type input unit, and the transfer object to which the toner image from the transfer object type input unit is transferred is transferred. A simple operation just by inputting the type, the image bearing member coated with a solid lubricant on the surface and the solid image transferred from the intermediate transfer member to the transfer target, etc. Image generation It is to be able to provide an image forming apparatus to prevent.
[0007]
Claim 3 The present invention according to the present invention is an image forming apparatus in which at least the intermediate transfer member is detachable from the main body device. Special It is a sign. Claim 3 According to the present invention, a toner image formed by a developing unit is applied to an image carrier having a solid lubricant applied to a surface layer by a solid lubricant applying unit, and an image carrier having a solid lubricant applied to the surface layer by a solid lubricant applying unit. The toner image transferred by the first transfer unit to the intermediate transfer member that rotates in synchronization with the first transfer unit is transferred to the first transfer unit. The transfer bias switching means of the transfer means switches the transfer bias of the first transfer means and the intermediate transfer body can be attached to and detached from the main body device, so that the intermediate transfer body is replaced with a new one from the used intermediate transfer body. It is possible to replace the intermediate transfer member, and an image bearing member on which a solid lubricant is applied on the surface layer and a solid image transferred from the intermediate transfer member to the transfer member, etc. Prevent occurrence It is to be able to provide that image forming apparatus. Claim 4 The invention according to the present invention is an image forming apparatus that counts the number of use rotations of the intermediate transfer member by a use frequency counting unit. Special It is a sign. Claim 4 According to the present invention, a toner image formed by a developing unit is applied to an image carrier in which a solid lubricant is applied to a surface layer by a solid lubricant applying unit, and an image carrier in which a solid lubricant is applied to the surface layer by a solid lubricant applying unit. The toner image transferred by the first transfer unit to the intermediate transfer member that rotates in synchronization with the first transfer unit is transferred to the first transfer unit. The transfer bias switching means of the transfer means switches the transfer bias of the first transfer means, and the use frequency counting means counts the number of rotations of the intermediate transfer body, so that the intermediate transfer body can be counted over time. The solid image of the solid lubricant applied to the surface layer and the solid image transferred from the intermediate transfer body to the transfer target body, etc. Sutra It is so can be provided which suppresses image forming apparatus insufficient density in. Claim 5 The invention according to the present invention is an image forming apparatus that resets the count of the number of times of use rotation of the use frequency counting means by attaching and detaching the intermediate transfer member to the main body device. Special It is a sign. Claim 5 According to the present invention, a toner image formed by a developing unit is applied to an image carrier having a solid lubricant applied to a surface layer by a solid lubricant applying unit, and an image carrier having a solid lubricant applied to the surface layer by a solid lubricant applying unit. The toner image transferred by the first transfer unit to the intermediate transfer member that rotates in synchronization with the first transfer unit is transferred to the first transfer unit. The transfer bias switching means of the transfer means switches the transfer bias of the first transfer means, and the usage frequency counting means resets the count of the number of rotations of use by attaching / detaching the intermediate transfer body to / from the main body device. The initial state of the image can be counted, and the image bearing member on which the solid lubricant is applied to the surface layer and the solid image transferred from the intermediate transfer member to the transfer target member, etc., have white and dark images that are referred to as “bokeh” Preventing generation by the initial, it is to be able to provide an inhibiting image forming apparatus insufficient density in aging.
[0008]
Claim 6 The transfer bias switching means of the first transfer means is an image forming apparatus comprising an intermediate transfer body use frequency input means for inputting the number of use rotations counted by the intermediate transfer body use frequency counting means. The It is a sign. Claim 6 According to the present invention, a toner image formed by a developing unit is applied to an image carrier having a solid lubricant applied to a surface layer by a solid lubricant applying unit, and an image carrier having a solid lubricant applied to the surface layer by a solid lubricant applying unit. The toner image transferred by the first transfer unit to the intermediate transfer member that rotates in synchronization with the first transfer unit is transferred to the first transfer unit. The transfer bias switching means of the transfer means switches the transfer bias of the first transfer means, and the transfer bias switching means of the first transfer means inputs the number of times of use rotation counted by the use frequency counting means of the intermediate transfer body. An image carrier with a solid lubricant applied to the surface layer with a simple operation of inputting the number of rotations of the intermediate transfer body from the intermediate transfer body usage frequency input means. And an image forming apparatus that prevents an initial occurrence of a white-out image having a density called “blush” in a solid image or the like transferred from an intermediate transfer body to a transfer body, and suppresses a lack of density over time. To be able to Claim 7 The transfer bias switching means of the first transfer means according to the present invention is an image forming apparatus capable of switching the transfer bias according to the number of use rotations of the use frequency counting means of the intermediate transfer member. Special It is a sign. Claim 7 According to the present invention, a toner image formed by a developing unit is applied to an image carrier having a solid lubricant applied to a surface layer by a solid lubricant applying unit, and an image carrier having a solid lubricant applied to the surface layer by a solid lubricant applying unit. The toner image transferred by the first transfer unit to the intermediate transfer member that rotates in synchronization with the first transfer unit is transferred to the first transfer unit. The transfer bias switching means of the transfer means switches the transfer bias of the first transfer means, and the transfer bias switching means of the first transfer means switches the transfer bias according to the number of rotations of the use frequency counting means, so that the intermediate transfer body By switching the transfer bias of the first transfer means over time, the solid image is transferred from the image carrier having the solid lubricant applied to the surface layer and the intermediate transfer member to the transfer target. The generation by the initial white spot image having shading is prevented called "irregularity", it is to be able to provide an inhibiting image forming apparatus insufficient density in aging.
[0009]
Claim 8 The transfer bias switching means of the first transfer means is an image forming apparatus that switches the transfer bias to be higher by increasing the number of times of use rotation of the intermediate transfer body use frequency counting means. Special It is a sign. Claim 8 According to the present invention, a toner image formed by a developing unit is applied to an image carrier having a solid lubricant applied to a surface layer by a solid lubricant applying unit, and an image carrier having a solid lubricant applied to the surface layer by a solid lubricant applying unit. The toner image transferred by the first transfer unit to the intermediate transfer member that rotates in synchronization with the first transfer unit is transferred to the first transfer unit. The transfer bias switching means of the transfer means switches the transfer bias of the first transfer means, and the transfer bias switching means of the first transfer means increases the transfer bias by increasing the number of use rotations of the use frequency counting means of the intermediate transfer member. In this way, the image bearing member on which the solid lubricant is applied to the surface layer and the solid image transferred from the intermediate transfer member to the transfer target member have a density called “blossiness”. Generation of an image, it is to be able to provide automatically suppresses the image forming apparatus to "insufficient density" in time. Claim 9 The image forming apparatus includes a toner charge amount detection unit that detects the toner charge amount of the reference pattern transferred to the intermediate transfer member, and the transfer bias switching unit of the first transfer unit is detected by the toner charge amount detection unit. Toner charge amount According to the increase of Transfer bias To lower It is characterized by switching. Claim 9 The invention further comprises a toner charge amount detection means for detecting the toner charge amount of the reference pattern transferred to the intermediate transfer body, and the transfer bias switching means of the first transfer means is a toner charge amount detected by the toner charge amount detection means. According to the increase of Transfer bias To lower When switching, the transfer bias is set based on the detected toner charge amount, and when an image is formed on a transfer medium such as thick paper or paper with poor smoothness, the occurrence of a white-out image with a density called “bottle” In addition, it is possible to obtain a good image by preventing the “black” greening of 3C black.
[0010]
Claim 10 The image forming apparatus includes a toner adhesion amount detection unit that detects the toner adhesion amount of the reference pattern transferred to the intermediate transfer member, and a prediction unit that predicts the toner charge amount with respect to the developing bias with respect to the toner adhesion amount. The transfer bias switching means of one transfer means is a toner charge amount predicted by the prediction means. According to the increase of Transfer bias To lower It is characterized by switching. Claim 10 The first transfer means includes a toner adhesion amount detection means for detecting the toner adhesion quantity of the reference pattern transferred to the intermediate transfer member, and a prediction means for predicting the toner charge quantity with respect to the developing bias with respect to the toner adhesion quantity. The transfer bias switching means of the toner charging amount predicted by the prediction means According to the increase of Transfer bias To lower Therefore, the toner charge amount corresponding to the developing bias is predicted from the toner adhesion amount, the transfer bias is set based on the predicted toner charge amount, and an image is formed on a transfer medium such as thick paper or paper with poor smoothness. At this time, it is possible to eliminate the occurrence of a white-spotted image having a light and darkness called “bottle”, and to prevent the “black” of 3C black from being greened, thereby obtaining a good image.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a configuration diagram of an embodiment of an image forming apparatus to which the present invention is applied. An image carrier 1 is a belt-like photoconductor that is a belt-like image carrier. It is constructed between the moving rollers 1a and 1b, and is conveyed in the clockwise direction of the arrow A shown in the figure by the rotational drive of the rotating roller 1a. The first solid lubricant 2 is applied to the surface layer of the belt-like photoreceptor 1 in the first solid lubricant. It is applied by the application means 3.
On the outer periphery of the belt-like photosensitive member 1, a charging charger 11 for uniformly charging the surface of the belt-like photosensitive member 1, and a static light for writing laser light on the belt-like photosensitive member 1 corresponding to a document image (not shown). An electric image exposure means 12 is arranged.
Further, the intermediate transfer belt as the intermediate transfer member 5 is installed between the rotation rollers 5b and 5c, and is conveyed in the counterclockwise direction indicated by the arrow B in the drawing by the rotation of the rotation roller 5b. The second solid lubricant 6 is applied by the second solid lubricant applying means 7.
The frequency of use of the unitized intermediate transfer belt 5 is obtained by counting the number of times of rotation of the intermediate transfer belt 5 by the use frequency counting means 5a.
A new article of the intermediate transfer belt 5 is detected by the attachment / detachment detecting means 5d for detecting attachment / detachment of the unitized intermediate transfer belt 5 to / from the main body device 0a, and the count by the use frequency counting means 5a is reset.
The belt-like photoreceptor 1 and the intermediate transfer belt 5 are in contact with each other at the position of the rotation roller 1b of the belt-like photoreceptor 1.
On the intermediate transfer belt 5 side of the contact portion between the belt-like photoconductor 1 and the intermediate transfer belt 5, a transfer bias switching unit that switches a transfer bias as a first transfer unit 8 and a conductive bias roller are provided on the intermediate transfer belt 5. The toner image formed on the belt-like photosensitive member 1 is primarily transferred to the intermediate transfer belt 5 by contacting the back side of the belt-like photoreceptor under predetermined conditions.
Note that the transfer bias switching means of the first transfer means 8 is provided in the first transfer means 8, and is based on the type of the transfer target (P) and the number of rotations of the intermediate transfer body 5. Switch the primary transfer bias.
The superposed toner images that have been subjected to the primary transfer to the intermediate transfer belt 5 by the bias roller having a medium resistance as the second transfer means 9 and successively transferred in succession are collectively transferred to the transfer medium (P) and subjected to the secondary transfer. Is called. In FIG. 1, since the front frame 0b is in an open state, the second transfer unit 9 is separated from the surface of the intermediate transfer belt 5 (second transfer position). Since the second transfer means 9 is close to the surface of the intermediate transfer belt 5, secondary transfer is performed.
[0012]
Here, a color image forming operation in the image forming apparatus according to the embodiment of the present invention will be described.
The belt-like photosensitive member 1 is uniformly charged on the surface by a charging charger as the charging unit 11, and then scanned and exposed by laser light corresponding to document image information (not shown) by the electrostatic image exposure unit 12. An electrostatic latent image is formed.
Here, the original image information to be scanned and exposed is single-color original image information that is decomposed into desired full-color image color information of yellow, cyan, magenta, and black. Based on this information, a laser generated by a semiconductor laser (not shown) The beam (L) is scanned and the optical path is adjusted by the electrostatic image exposure means 12.
The electrostatic latent image formed here is developed in a single color in predetermined yellow, cyan, magenta, and black, respectively, by the rotary developing device of the developing means 4, and the respective color images are sequentially formed on the belt-like photoreceptor 1. It is formed.
Each single-color image formed on the belt-shaped photoconductor 1 rotating in the direction of the arrow A shown in the drawing is yellow, on the intermediate transfer belt 5 rotating in the direction of the arrow B in synchronization with the belt-type photoconductor 1. For each color of cyan, magenta, and black, the images are sequentially superimposed and transferred by a transfer bias applied to a conductive bias roller of the first transfer unit 8.
The primary transfer bias applied to the conductive bias roller 8 includes information on the type of the transfer target (P) input from the transfer target type input unit 10a and the number of use times counted by the use frequency counting unit 5a. Switching is made according to information from the intermediate transfer member use frequency input means 10b for inputting the number of movements.
When the surface state of the intermediate transfer body changes between the initial state and the time-lapse state, transfer defects occur due to the change. For this reason, by counting the number of rotations of the intermediate transfer member, the initial state and the aging state of the intermediate transfer member are separated, and the transfer failure is improved by switching the primary transfer bias.
[0013]
When the transfer material (P) to which the toner image is transferred by the second transfer means 9 is a thick paper of 90 (kg paper) or more, or particularly when the transfer paper has poor smoothness, the transfer of the first transfer means When the transferred object type input means 10a is turned on at the initial stage of the transfer by the bias switching means 10, the applied voltage of the bias roller 8 is that when the transferred object (P) has a normal thickness of around 70 (kg paper). The applied voltage is switched to 600 (V), which is lower than the applied voltage 800 (V) at the time of transfer to a transfer paper having normal smoothness. This is because, for example, until the start of the use of a new intermediate transfer member, 300 sheets of A3 paper are copied (up to 2400 count in the PCU count), while accepting the decrease in density, the primary is to prioritize the improvement of transfer defects. The transfer bias is lowered.
Further, when 2400 counts are input to the intermediate transfer body usage frequency input means 10b over time when the usage frequency of the intermediate transfer body 5 is increased, counted by the usage frequency counting means 5a, the first transfer means 8 The applied voltage of the bias roller having conductivity is switched again from 600 (V) to 800 (V).
FIG. 2 is a diagram showing the characteristics of the primary transfer bias of the first transfer means and the 3C greening rank. FIG. 3 shows the transfer paper (P) over 90 (kg paper) thick transfer paper over time. This is an evaluation result of a transfer defect rank using a white-spotted image having light and darkness, which is referred to as “Bosseki”. If the primary transfer bias is lowered, there are problems such as a decrease in transfer rate when three colors are superimposed and reverse transfer, and the image density is lowered. Therefore, it is not preferable to greatly reduce the primary transfer bias. In addition, increasing the secondary transfer pressure causes a load in the secondary transfer to be applied to the drive unit and cause color overlap.
For this reason, in this embodiment, in order to improve the transfer failure on the thick paper without affecting the color overlap, the primary transfer bias when transferring to the thick paper is switched. When there is insufficient pressure, such as when transferring to thick paper, or when the paper is not smooth, there is a demerit that the density decreases slightly, but the image due to transfer failure is improved by lowering the primary transfer bias. can do.
[0014]
When the intermediate transfer member is in the initial state, the transfer failure rank is further deteriorated by one rank as compared with the case where the intermediate transfer member is used over time (here, a larger numerical value means a better state). In other words, with respect to FIG. 3, the initial transfer failure rank when the transfer bias of 800 V is used is 2, the rank is 3 in the case of 600 V, and the transfer is better in rank 3. Therefore, when the intermediate transfer member 5 is in the initial state, the voltage applied to the bias roller having the conductivity of the first transfer unit 8 is lowered from 800 V to 600 V, and white spots having a density called “bottle” are obtained. Control is performed so that “rank 2” (800 V) of the transfer failure rank (initial state rank) by the image is changed to “rank 3” (600 V). When the density is insufficient such as the “3C greening rank” shown in FIG. 2, the density slightly decreases, but “Rank 4” does not change for both 800V and 600V.
Here, the 3C greening rank will be described. When forming a color image by superposing four colors of yellow, cyan, magenta, and black, black is obtained by superimposing the three colors of yellow, cyan, and magenta in that order. Although it can be obtained, in order to transfer magenta coming from the uppermost layer onto the cyan layer, it is necessary to increase the primary transfer bias. However, in the case where the primary transfer bias needs to be lowered as described above, the magenta cannot be sufficiently overlapped, so that the obtained color becomes black close to green. FIG. 2 shows the degree to which the black color obtained here is close to green. Then, when the intermediate transfer member is used over time, the first transfer is performed again so that the generation of white-out images having light and darkness called “bottle” over time is improved and the density is not insufficient. The applied voltage of the bias roller having conductivity of the means 8 is increased.
The yellow, cyan, magenta, and black toner images superimposed on the intermediate transfer belt 5 are fed from the paper feed cassette of the paper feed means 13 to the paper feed roller 14, the transport roller 15a and the transport roller 15b of the transport roller pair 15, or The thick paper having the transfer material (P) of 90 (kg paper) or more is fed from the manual paper feeding means 13a in the direction of the arrow C shown in the figure, and passes through the registration rollers 16a and 16b of the registration roller pair 16. Secondary transfer is collectively performed on the transfer target (P) conveyed to the second transfer unit 9 by a bias roller having a medium resistance of the second transfer unit 9.
After the secondary transfer is completed at once by the bias roller having the intermediate resistance of the second transfer means 9, the transfer target (P) is fixed by the fixing means 17, and a full color image is completed, and the paper discharge roller The formed images are discharged and stored in the paper discharge stack 19 through the pair of paper discharge rollers 18a and 18b.
[0015]
The cleaning means 20 is a cleaning device that includes a cleaning blade 20a that always contacts the belt-like photoreceptor 1 and cleans residual toner on the belt-like photoreceptor 1 and a waste toner collection container 20b.
The intermediate transfer body cleaning unit 21 is a cleaning device for the intermediate transfer belt 5, and the cleaning blade 21 a is held at a position separated from the surface of the intermediate transfer belt 5 during the image forming operation, and the formed image is transferred to the transfer target ( P) After being transferred onto the intermediate transfer belt 5, the intermediate transfer belt 5 is contacted.
The waste toner scraped off from the intermediate transfer belt 5 by the cleaning blade 21a is transported to the front side of the drawing by the auger 21b, and is further discarded by a transport unit (not shown) disposed on the front side of the process cartridge 22. It is conveyed to 20b. By replacing the process cartridge 22 when a predetermined amount or more of waste toner is accommodated in the discarded toner collection container 20b, the life of the process cartridge 22 can be extended.
The belt-shaped photosensitive member 1, the charging charger of the charging unit 11, the intermediate transfer belt 5, the cleaning unit 20, and the intermediate transfer unit cleaning unit 21 are integrally unitized as a process cartridge 22, and the discarded toner collection container 20b is a process cartridge. 22 is exchangeably incorporated. The case exterior portion on the registration roller pair 16 side of the process cartridge 22 has a function as a conveyance guide for the transfer target (P).
The main body device 0 includes a stationary housing of the main body frame 0a and a front frame 0b which is a front housing having an open conveyance path for the transfer target (P). The developing device 4 and the process cartridge 22 are replaceably disposed inside the main body device 0, and further, a fixing unit 17 is disposed above the main body device 0. A stack 19 is arranged.
The front frame 0b is supported so as to be able to open and close around a rotation support shaft 0c provided in the main body frame 0a, and normally rotates in the direction of the arrow D shown in the figure and is held in a closed state with respect to the main body frame 0a. Has been.
When a transfer failure of the transfer target (P) occurs in the transfer path, the lock mechanism of the front frame 0b (not shown) is released, and the front frame 0b is opened in the direction opposite to the arrow D direction as shown. It can be done.
In the front frame 0b, the conveyance rollers 15a and 15b of the conveyance roller pair 15 or the manual paper feeding unit 13a and the registration rollers 16a of the registration roller pair 16 constituting a part of the conveyance path of the transfer target (P), 16b, a bias roller having a middle resistance of the second transfer means 9, and the like, are held, and by opening the front frame 0b in the direction opposite to the direction of the arrow D shown in the figure, the transfer path of the transfer object (P) Is exposed, and the transfer failure processing of the transfer target (P) can be easily performed.
At this time, the other image forming units do not move, and problems such as toner scattering and leakage do not occur.
[0016]
FIG. 4 is a configuration diagram around the first solid lubricant applying means. The first solid lubricant applying means 3 is provided in the cleaning means 20 and applies the first solid lubricant 2 to the belt-shaped photoreceptor 1. A brush roller 3a, a holding member 3b that holds and rotates the first solid lubricant 2, and the holding member 3b in the direction of arrow E shown in the figure so that the first solid lubricant 2 contacts the brush roller 3a. And a spring of a biasing member 3c that biases the spring.
The brush roller 3a of the first solid lubricant applying means 3 is brought into contact with the belt-shaped photosensitive member 1 by the rotation in the direction indicated by the arrow A and is driven to rotate in the direction indicated by the arrow F. At this time, the rotatable holding member 3b is urged by the spring of the urging member 3c in the direction of the arrow E shown in the figure, so that the first solid lubricant 2 comes into contact with the brush roller 3a and the first A part of the solid lubricant 2 is scraped by the brush roller 3a, and the first solid lubricant 2 attached to the surface of the brush roller 3a adheres to the surface of the belt-like photoreceptor 1 to form a coating layer thickness.
The 1st solid lubricant 2 melt | dissolves the lubricating oil additive which has a zinc stearate as a main component, Then, it cools and solidifies in the rod shape. As the first solid lubricant 2, in addition to zinc stearate, stearic acid groups such as barium stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, strontium stearate, calcium stearate, etc. You can use the one with
Also, the same fatty acid group zinc oleate, barium oleate, lead oleate, the same as stearic acid, zinc palmitate, barium palmitate, lead palmitate, the same as stearic acid may be used. .
In addition, caprylic acid, linolenic acid, corinolenic acid and the like can be used as the fatty acid group. In addition, waxes such as candelilla wax, canrunauba wax, rice wax, wood wax, sesame oil, beeswax and lanolin can also be used.
These are organic solid lubricants and are easy to use because they are compatible with toner. Teflon and inorganic solid lubricants can also be used depending on the toner.
[0017]
FIG. 5 and FIG. 6 are diagrams for explaining the configuration of the second solid lubricant applying means. The second solid lubricant applying means 7 is provided in the intermediate transfer body cleaning means 21 and transfers the second solid lubricant 6 to the intermediate transfer. A brush roller 7a for applying to the belt 5 is provided.
The brush roller 7a of the second solid lubricant applying means 7 is brought into contact with the rotation of the intermediate transfer belt 5 in the direction indicated by the arrow B and is driven to rotate in the direction indicated by the arrow G.
At this time, the second solid lubricant 6 comes into contact with the brush roller 7a under its own weight, and a part of the second solid lubricant 6 is scraped by the brush roller 7a and adheres to the surface of the brush roller 7a. 6 adheres to the surface of the intermediate transfer belt 5 to form a coating layer thickness.
The second solid lubricant 6 is obtained by dissolving a lubricant additive mainly composed of zinc stearate and then cooling and solidifying it into a rod shape, and the same as the first solid lubricant 2 is used. Since the description is duplicated, the following is omitted.
In the above embodiment, the first transfer unit 8 is based on the type of the transfer target (P) input from the transfer target type input unit 10a and the number of rotations of use from the intermediate transfer unit use frequency input unit 10b. The transfer bias switching means switches the primary transfer bias, and when the transfer target (P) is a thick paper, the density called “blossiness” on a solid image or the like transferred from the intermediate transfer member 5 to the transfer target (P). An image forming apparatus that prevents the occurrence of white spots having the above has been described.
[0018]
Next, an embodiment in which the primary transfer bias is switched when the toner charge amount of the reference pattern transferred to the intermediate transfer body and the transfer target (P) are thick paper will be described.
FIG. 7 is a block diagram of the main part of another embodiment of the control system of the image forming apparatus according to the present invention.
In FIG. 7, the control system of the image forming apparatus includes a first transfer unit 8 having a transfer object type input type 10a, a toner charge amount detection unit 30, a transfer bias switching unit and a conductive bias roller shown in FIG. Prepare.
The toner charge amount detection unit 30 detects the toner charge amount of the reference pattern of the solid pattern image formed on the intermediate transfer belt 5. The transferred object type input type 10a outputs information on the target transferred object (P) being thick paper or paper with poor smoothness.
The transfer bias switching means of the first transfer means 8 switches the transfer bias based on the toner charge amount supplied from the toner charge amount detection means 30 and the transfer object type information supplied from the transfer object type input type 10a. A primary transfer bias (voltage) is supplied to the intermediate transfer belt 5 via a bias roller.
Here, the relationship between the toner charge amount and the transfer bias will be described in detail. When thick paper or paper with poor smoothness is passed through the image forming apparatus, an image defect called “bottled” with poor solid image filling as shown in FIG. 15 occurs.
This “bottleness” tends to deteriorate as the toner charge amount on the intermediate transfer belt 5 increases.
FIG. 8 shows an evaluation rank of “bottleness” on thick paper with respect to the toner charge amount.
In FIG. 8, the evaluation rank of “Bosseki” is determined in five stages with visual evaluation and rank 5 being the best. The evaluation rank decreases as the absolute value of the toner charge amount increases, and rank 4 when the toner charge amount is −18 (μc / g) and rank 3 when the toner charge amount is −24 (μc / g).
The image forming apparatus using the intermediate transfer method sequentially superimposes the toner from the photosensitive member to the intermediate transfer member, so that the toner first transferred onto the intermediate transfer member first is the primary of another color that is subsequently executed. At the time of transfer, the toner charge amount on the intermediate transfer member tends to increase due to the discharge generated between the photosensitive member and the intermediate transfer member.
For example, yellow toner is first transferred to the intermediate transfer member first, and then transferred to the intermediate transfer member in the order of cyan toner, magenta toner, and black toner, so that the discharge phenomenon between the photosensitive member and the intermediate transfer member. As a result, the toner charge amount on the intermediate transfer member increases in the order of yellow toner, cyan toner, magenta toner, and black toner in the order of image formation.
[0019]
FIG. 11 is a characteristic diagram of the number of primary transfers and the toner charge amount using the primary transfer bias as a parameter.
In FIG. 11, the toner charge amount increases as the primary transfer bias increases and the number of primary transfers increases.
FIG. 12 shows a change with time of the toner charge amount.
In FIG. 12, the toner charge amount tends to decrease with time, saturate and stabilize as the number of output sheets (P) increases. In particular, the toner charge amount shows a very high value in the initial stage.
As shown in the characteristics of FIG. 12, in the image forming apparatus using the intermediate transfer method, when the developing device is in the initial state, the toner charge amount on the intermediate transfer is very high, so that the primary transfer is executed sequentially. As shown in FIG. 11, if the toner charge amount on the intermediate transfer is further increased and secondary transfer is performed on thick paper or paper with poor smoothness, “blossiness” generated in an image formed on the paper surface is deteriorated.
In order to avoid the deterioration of “bottleness”, when the toner charge amount is high in the initial state of the developing device, the increase in the toner charge amount in the primary transfer must be suppressed, and the primary transfer bias needs to be set low. is there.
However, when the primary transfer bias is set too low, transfer shortage may occur. When the yellow toner, cyan toner, magenta toner, and black toner are sequentially superimposed on the intermediate transfer member in order, the yellow toner, cyan toner, and magenta toner are superimposed to reproduce “black” (3C black) with three colors. The magenta toner is not sufficiently transferred to the intermediate transfer member, resulting in a greenish black.
FIG. 9 is a rank evaluation diagram of the primary transfer bias and 3C greening.
In FIG. 9, rank evaluation is performed by visual five-level evaluation, and if it is rank 3 or higher, it can be sufficiently judged as “black”. From the rank evaluation chart, it can be seen that if the primary transfer bias is 600 V or more, it is satisfied as “black”.
Note that FIG. 2 also has a rank evaluation diagram similar to that in FIG. 9, and the rank evaluation values are different.
[0020]
Returning to FIG. 7, when the toner charge amount detection means 30 detects the toner charge amount −24 (μc / g) (“bottle” rank 3 shown in FIG. 8), the transfer bias switching means uses the toner charge amount −24. Switch to the primary transfer bias 600V (3C black green rank 3) shown in FIG. 9 corresponding to (μc / g), and lower the primary transfer bias to the extent that 3C black appears to be “black” to improve the “blur”. , Image defects can be eliminated.
Further, when the toner charge amount detecting means 30 detects the toner charge amount −18 (μc / g) (“BOSOKI” rank 4 shown in FIG. 8), the transfer bias switching means detects the toner charge amount −18 (μc / g). The primary transfer bias 800V (3C black green rank 4) shown in FIG. 9 corresponding to g) can be switched to emphasize “black” of 3C black, improve “blur”, and eliminate image defects. .
Next, an embodiment will be described in which, when the transfer target (P) is a cardboard, the toner charge amount is predicted from the toner adhesion amount of the reference pattern transferred to the intermediate transfer member, and the primary transfer bias is switched.
FIG. 13 is a block diagram of the main part of another embodiment of the control system of the image forming apparatus according to the present invention.
In FIG. 13, the control system of the image forming apparatus is a first having a transfer material type input unit 10a, a toner adhesion amount detection unit 31, a prediction unit 32, a transfer bias switching unit and a conductive bias roller shown in FIG. A transfer means 8 is provided.
The toner adhesion amount detection means 31 detects the toner adhesion amount of the reference pattern of the solid pattern image formed on the intermediate transfer belt 5. The prediction unit 32 is configured by a memory such as a ROM, and predicts the toner charge amount with respect to the developing bias for the toner adhesion amount detected by the toner adhesion amount detection unit 31. The transferred object type input type 10a outputs information on the target transferred object (P) being thick paper or paper with poor smoothness.
[0021]
FIG. 14 shows a prediction characteristic diagram of the prediction means according to the present invention.
In FIG. 14, the expected characteristic diagram shows a fixed amount m (= 0.65 mg / cm) of the toner adhesion amount of the reference pattern of the solid pattern image formed on the intermediate transfer belt 5. ² ) Represents the relationship between the developing bias and the toner charge amount when controlled.
The transfer bias switching means of the first transfer means 8 switches the transfer bias based on the toner charge amount supplied from the toner adhesion amount detection means 31 and the transfer object type information supplied from the transfer object type input type 10a. A primary transfer bias (voltage) is supplied to the intermediate transfer belt 5 via a bias roller.
Usually, the toner density on the photosensitive member or the intermediate transfer member is controlled so that the image density of the image formed by the image forming apparatus is constant. First, a reference pattern is formed on the photoconductor. Next, this reference pattern is primarily transferred onto the intermediate transfer means.
The toner adhesion amount on the intermediate transfer unit is detected by the toner adhesion amount detection unit 31, and the development bias and the charging grid bias are controlled so as to reach the target toner adhesion amount on the intermediate transfer unit from the detected toner adhesion amount. To do.
In order to keep the toner adhesion amount m on the intermediate transfer unit at a constant value, the development bias tends to be low when the toner charge amount is low, and the development bias tends to be high when the toner charge amount is high.
Thus, from FIG. 14, the toner charge amount that makes the toner adhesion amount a fixed amount m can be predicted from the development bias.
The toner adhering amount detecting means 31 has a constant toner adhering amount m (= 0.65 mg / cm ² ) Is detected, and when the developing bias is −300 V, the predicted toner charge amount is −22 (μc / g), the evaluation rank (rank 3) of “Bosseki” shown in FIG. 8 and 3C green shown in FIG. From the rank evaluation of rank (rank 3), the transfer bias switching means switches the primary transfer bias to 600 V, improves the greening and “bottleness” of “black” of 3C black, and can eliminate image defects.
Further, when the developing bias is −250 V, the predicted toner charge amount is −18 (μc / g), and the “rank” evaluation rank (rank 4) shown in FIG. 8 and the 3C greening rank evaluation shown in FIG. From (Rank 4), the transfer bias switching means can switch the primary transfer bias to 800 V, improve the greening and “blurring” of “black” of 3C black, and eliminate image defects.
[0022]
【The invention's effect】
Since the present invention is configured as described above, according to the first aspect of the present invention, the toner formed by the developing means on the image carrier in which the solid lubricant is applied to the surface layer by the solid lubricant applying means. The toner image transferred by the first transfer unit is transferred to the transfer target body, and the image is transferred to the intermediate transfer member that is rotated by the solid lubricant applied to the surface layer by the solid lubricant applying unit and synchronized with the image carrier. Depending on the type of transfer target to which the toner image is transferred by the second transfer means, the transfer bias switching means of the first transfer means, When the transfer object is thick or when its smoothness decreases, The transfer bias of the first transfer means To be lower Since it is switched, it prevents the occurrence of white-out images with a contrast called “blossiness” in the solid image transferred from the intermediate carrier to the image carrier with the solid lubricant applied to the surface layer, etc. An image forming apparatus can be provided. That is, since the solid lubricant applying means for improving the toner releasability is provided on the image carrier and the intermediate transfer member, it is possible to effectively prevent the toner from adhering to the intermediate transfer member with excessive force. Can prevent degradation of image quality . Also, A white image having a density called “bokeh” on a solid image or the like that is transferred from an image bearing member and an intermediate transfer member having a solid lubricant applied to the surface layer to a transferred material having a large thickness or poor smoothness. It has become possible to provide an image forming apparatus that prevents generation. That is, since the transfer bias of the first transfer means is switched according to the thickness and smoothness of the transfer paper, it is possible to appropriately prevent the image quality from being deteriorated.
[0023]
Claim 2 According to the invention, the toner image formed by the developing means on the image carrier on which the solid lubricant is applied to the surface layer by the solid lubricant applying means is applied to the image formed by applying the solid lubricant to the surface layer by the solid lubricant applying means. The toner image transferred by the first transfer unit is transferred to the intermediate transfer member that rotates in synchronization with the carrier, and the type of transfer target to which the toner image is transferred by the second transfer unit that transfers to the transfer target. Since the transfer bias of the first transfer unit is switched by the transfer bias switching unit of the first transfer unit in accordance with the input from the transfer member type input unit, the toner image from the transfer member type input unit is transferred. By simply inputting the type of transfer material, the image carrier with a solid lubricant applied to the surface layer and the solid image transferred from the intermediate transfer material to the transfer material, etc. can be said to have a “buzziness”. White spots It has become possible to provide an image forming apparatus to prevent the occurrence of image. Claim 3 According to the invention, the toner image formed by the developing means on the image carrier on which the solid lubricant is applied to the surface layer by the solid lubricant applying means is applied to the image formed by applying the solid lubricant to the surface layer by the solid lubricant applying means. The toner image transferred by the first transfer unit to the intermediate transfer member that rotates in synchronization with the carrier is transferred to the transfer member by the type of transfer target to which the toner image is transferred by the second transfer unit. The transfer bias switching unit of the first transfer unit switches the transfer bias of the first transfer unit and the intermediate transfer member can be attached to and detached from the main body device. Therefore, the used intermediate transfer member is replaced with a new intermediate transfer member. An image that can be used to prevent the occurrence of a white-out image having a shading that is referred to as “bottle” in a solid image or the like that is transferred from an intermediate transfer body to an image transfer body and an image bearing body coated with a solid lubricant on the surface layer form It has become possible to provide a device. Claim 4 According to the invention, the toner image formed by the developing means on the image carrier on which the solid lubricant is applied to the surface layer by the solid lubricant applying means is applied to the image formed by applying the solid lubricant to the surface layer by the solid lubricant applying means. The toner image transferred by the first transfer unit to the intermediate transfer member that rotates in synchronization with the carrier is transferred to the transfer member by the type of transfer target to which the toner image is transferred by the second transfer unit. Since the transfer bias of the first transfer unit is switched by the transfer bias switching unit of the first transfer unit and the use rotation count of the intermediate transfer member is counted by the use frequency counting unit, the time-lapse state of the intermediate transfer member is counted. It is possible to generate a white-out image having a gray level called “blossiness” in an image bearing member coated with a solid lubricant on the surface layer and a solid image transferred from the intermediate transfer member to the transfer target. Sealed, it has become possible to provide an inhibiting image forming apparatus insufficient density in aging.
[0024]
Claim 5 According to the invention, the toner image formed by the developing means on the image carrier on which the solid lubricant is applied to the surface layer by the solid lubricant applying means is applied to the image formed by applying the solid lubricant to the surface layer by the solid lubricant applying means. The toner image transferred by the first transfer unit to the intermediate transfer member that rotates in synchronization with the carrier is transferred to the transfer member by the type of transfer target to which the toner image is transferred by the second transfer unit. Since the transfer bias of the first transfer unit is switched by the transfer bias switching unit of the first transfer unit and the use frequency counting unit resets the count of the number of use rotations by attaching and detaching the intermediate transfer member to the main body device. The initial state of the intermediate transfer member can be counted, and the solid image with the solid lubricant applied to the surface layer and the solid image transferred from the intermediate transfer member to the transfer member have a density called “blossiness”. Omission preventing generation by the initial image, has become possible to provide an inhibiting image forming apparatus insufficient density in aging. Claim 6 According to the invention, the toner image formed by the developing means on the image carrier on which the solid lubricant is applied to the surface layer by the solid lubricant applying means is applied to the image formed by applying the solid lubricant to the surface layer by the solid lubricant applying means. The toner image transferred by the first transfer unit to the intermediate transfer member that rotates in synchronization with the carrier is transferred to the transfer member by the type of transfer target to which the toner image is transferred by the second transfer unit. The transfer bias switching unit of the first transfer unit switches the transfer bias of the first transfer unit, and the transfer bias switching unit of the first transfer unit inputs the number of use rotations counted by the use frequency counting unit of the intermediate transfer member. Since the transfer material usage frequency input means is used, the solid lubricant is applied to the surface layer with a simple operation by simply inputting the number of rotations of the intermediate transfer body from the intermediate transfer material usage frequency input means. An image forming apparatus that prevents the occurrence of an initial white-spotted image called “blush” in a solid image transferred from an image bearing member and an intermediate transfer member to a transfer target, etc., and suppresses insufficient density over time. It became possible to provide.
[0025]
Claim 7 According to the invention, the toner image formed by the developing means on the image carrier on which the solid lubricant is applied to the surface layer by the solid lubricant applying means is applied to the image formed by applying the solid lubricant to the surface layer by the solid lubricant applying means. The toner image transferred by the first transfer unit to the intermediate transfer member that rotates in synchronization with the carrier is transferred to the transfer member by the type of transfer target to which the toner image is transferred by the second transfer unit. The transfer bias switching unit of the first transfer unit switches the transfer bias of the first transfer unit and the transfer bias switching unit of the first transfer unit switches the transfer bias according to the number of rotations of the use frequency counting unit. By switching the transfer bias of the first transfer means over time of the intermediate transfer member, the solid lubricant is transferred from the image bearing member coated on the surface layer and the intermediate transfer member to the transfer target. Preventing generation due to the initial white spot image having a gray called "irregularity" in the solid image or the like, has become possible to provide an inhibiting image forming apparatus insufficient density in aging. Claim 8 According to the invention, the toner image formed by the developing means on the image carrier on which the solid lubricant is applied to the surface layer by the solid lubricant applying means is applied to the image formed by applying the solid lubricant to the surface layer by the solid lubricant applying means. The toner image transferred by the first transfer unit to the intermediate transfer member that rotates in synchronization with the carrier is transferred to the transfer member by the type of transfer target to which the toner image is transferred by the second transfer unit. The transfer bias switching means of the first transfer means switches the transfer bias of the first transfer means, and the transfer bias switching means of the first transfer means changes the transfer bias by increasing the number of use rotations of the use frequency counting means of the intermediate transfer member. Since it is switched so that it becomes higher, a solid image with a solid lubricant applied to the surface layer and a solid image transferred from the intermediate transfer member to the transfer target, etc., are shaded as `` buzziness '' Generation of white spots images, to provide automatically suppresses the image forming apparatus to "insufficient density" in time became possible.
[0026]
Claim 9 According to the invention, the toner charge amount detection means for detecting the toner charge amount of the reference pattern transferred to the intermediate transfer member is provided, and the transfer bias switching means of the first transfer means is the toner detected by the toner charge amount detection means. Charge amount According to the increase of Since the transfer bias is switched, the transfer bias is set based on the detected toner charge amount. To lower When setting and forming an image on a transfer medium such as thick paper or paper with poor smoothness, it eliminates the occurrence of white-out images with shading that is called “blossy” and makes 3C black “black” green Therefore, a good image can be obtained. Claim 10 According to the invention, the toner adhesion amount detection means for detecting the toner adhesion amount of the reference pattern transferred to the intermediate transfer member, and the prediction means for predicting the toner charge amount with respect to the developing bias with respect to the toner adhesion amount are provided. The transfer bias switching means of the transfer means is the toner charge amount predicted by the prediction means. According to the increase of Transfer bias To lower Therefore, the toner charge amount corresponding to the developing bias is predicted from the toner adhesion amount, the transfer bias is set based on the predicted toner charge amount, and an image is formed on a transfer medium such as thick paper or paper with poor smoothness. At this time, it is possible to eliminate the occurrence of a white-spotted image having a light and darkness called “bottle”, and to prevent the “black” of 3C black from being greened, thereby obtaining a good image. Therefore, it is possible to provide an image forming apparatus that eliminates the occurrence of a white-spotted image that is called “blossy” and prevents a 3C black “black” from being green and obtains a good image.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram illustrating characteristics of “primary transfer bias of a first transfer unit (8)” and “3C greening rank” of an image forming apparatus according to an exemplary embodiment of the present invention.
FIG. 3 is an explanatory diagram illustrating characteristics of “primary transfer bias of a first transfer unit (8)” and “transfer failure rank” of an image forming apparatus according to an embodiment of the present invention.
FIG. 4 is an explanatory diagram illustrating a main part of an image forming apparatus according to an exemplary embodiment of the present invention.
FIG. 5 is an explanatory diagram illustrating another main part of the image forming apparatus according to the exemplary embodiment of the present invention.
FIG. 6 is an exploded perspective view illustrating another main part of the image forming apparatus according to the embodiment of the present invention.
FIG. 7 is a block diagram of a main part of another embodiment of the control system of the image forming apparatus according to the present invention.
FIG. 8 is a diagram illustrating an evaluation rank of “bottleness” on thick paper with respect to a toner charge amount.
FIG. 9 is a rank evaluation diagram of primary transfer bias and 3C greening.
FIG. 10 is a characteristic diagram of the number of primary transfers and the toner charge amount using the primary transfer bias as a parameter.
FIG. 11 is a characteristic diagram of toner charge amount with time.
FIG. 12 is a block diagram of the main part of another embodiment of the control system of the image forming apparatus according to the present invention;
FIG. 13 is a prediction characteristic diagram of the prediction means according to the present invention.
FIG. 14 is a diagram showing a solid image formed by a conventional image forming apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 0 ... Main body apparatus, 0a ... Main body frame, 0b ... Front frame, 0c ... Rotation instruction | indication shaft, 1 ... Image carrier, 1a, 1b ... Turning roller, 2 ... 1st solid lubricant, 3 ... 1st solid lubricant Coating means, 3a ... brush roller, 3b ... holding member, 3c ... biasing member, 4 ... developing means, 5 ... intermediate transfer member, 5a ... usage frequency counting means, 5b, 5c ... rotating roller, 5d ... attachment / detachment detecting means , 6 ... second solid lubricant, 7 ... second solid lubricant application means, 7a ... brush roller, 8 ... first transfer means, 9 ... second transfer means, 10 ... transfer bias switching means of the first transfer means, DESCRIPTION OF SYMBOLS 10a ... Transfer object type input means, 10b ... Intermediate transfer body use frequency input means, 11 ... Charging means, 12 ... Electrostatic image exposure means, 13 ... Paper feed means, 13a ... Manual paper feed means, 14 ... Paper feed roller , 15 ... pair of conveying rollers, 15a, 15b ... conveying rollers DESCRIPTION OF SYMBOLS 16 ... Registration roller pair, 16a, 16b ... Registration roller, 17 ... Fixing means, 18 ... Discharge roller pair, 18a, 18b ... Discharge roller, 19 ... Discharge stack, 20 ... Cleaning means, 20a ... Cleaning blade, 20b ... Waste toner collection container 21. Intermediate transfer member cleaning means 21 a. Cleaning blade 21 b. Auger 22. Process cartridge 30. Toner charge amount detection means 31 31 Toner adhesion detection means 32.

Claims (10)

In an image forming apparatus for forming an image by collectively transferring a plurality of toner images sequentially formed on an image bearing member onto an intermediate transfer member and sequentially transferring the superimposed toner images to a transfer target member. A rotating image carrier, a first solid lubricant application means for applying a first solid lubricant to the surface layer of the image carrier, and the first solid lubricant on the surface layer by the first solid lubricant application means Developing means for forming a toner image on the applied image carrier, an intermediate transfer member that rotates in synchronization with the image carrier, and a second solid lubricant that is applied to the surface layer of the intermediate transfer member. A solid lubricant applying means; a first transfer means for primarily transferring a toner image onto the intermediate transfer body having the second solid lubricant applied to the surface layer by the second solid lubricant applying means; and the first transfer means. Transferred to the intermediate transfer member by Second transfer means for secondary transfer of the toner image to the transfer target, and primary transfer bias of the first transfer means according to the type of transfer target to which the toner image is secondarily transferred by the second transfer means. a transfer bias switches means of the first transfer means, Ri Tona, the transfer bias switches means of the first transfer unit, when the case where the transfer object is thick or where the smoothness is lowered, the first transfer means an image forming apparatus comprising switching Rukoto to be lower transfer bias. 2. The image forming apparatus according to claim 1 , wherein the transfer bias switching means of the first transfer means has a transferred object type input means for inputting the type of the transferred object. 3. The image forming apparatus according to claim 1 , wherein at least the intermediate transfer member is detachable from the main body device. 4. The image forming apparatus according to claim 1, wherein the number of use rotations of the intermediate transfer member is counted by a use frequency counting unit. 5. 5. The image forming apparatus according to claim 4, wherein a new article is detected by attaching / detaching the intermediate transfer member to / from the main body, and resetting the count of the number of times of use rotation by the use frequency counting means. 6. The image forming apparatus according to claim 1, wherein the transfer bias switching unit of the first transfer unit inputs the number of use rotations of the intermediate transfer unit counted by the use frequency counting unit. An image forming apparatus comprising a usage frequency input unit. The image forming apparatus according to any one of claims 1 to 6, the transfer bias switches means of the first transfer means, the transfer bias in accordance with the use number of times of rotation of the intermediate transfer member usage counting means has counted An image forming apparatus characterized in that switching is possible. 8. The image forming apparatus according to claim 1, wherein the transfer bias switching unit of the first transfer unit performs transfer in accordance with an increase in the number of rotations of the intermediate transfer body counted by the use frequency counting unit. An image forming apparatus, wherein switching is performed so that a bias is increased. 3. The image forming apparatus according to claim 2 , further comprising a toner charge amount detection unit that detects a toner charge amount of a reference pattern transferred to the intermediate transfer member, wherein the transfer bias switching unit of the first transfer unit includes the toner charge amount. An image forming apparatus, wherein the transfer bias is switched to be lowered in accordance with an increase in the toner charge amount detected by the detecting means. 3. The image forming apparatus according to claim 2, wherein a toner adhesion amount detection unit that detects a toner adhesion amount of a reference pattern transferred to the intermediate transfer member, a prediction unit that predicts a toner charge amount with respect to a developing bias with respect to the toner adhesion amount, And the transfer bias switching means of the first transfer means switches so as to lower the transfer bias according to the increase in the toner charge amount predicted by the prediction means.

Images