JP3931943B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a printer, and in particular, an image forming method in which a toner image on an image carrier is transferred to a recording material and residual toner on the image carrier is cleaned by a cleaning unit. It relates to the improvement of the apparatus.
[0002]
[Prior art]
As an example of a conventional image forming apparatus, for example, an intermediate transfer type image forming apparatus, for example, black (K), yellow (Y), magenta (M), and the like around a latent image carrier such as a photosensitive drum. A developing device for each color component of cyan (C) is provided, and an intermediate transfer belt, for example, is disposed facing the latent image carrier, and each color formed on the latent image carrier for each rotation of the latent image carrier. After primary transfer of the unfixed toner image of the components to the intermediate transfer belt sequentially, the composite primary transfer image superimposed on the intermediate transfer belt is secondarily transferred to a recording material such as paper or OHP, and a desired image is transferred onto the recording material. (See, for example, JP-A-5-323704).
According to this type, since the composite toner image that has already been multiplex-transferred onto the intermediate transfer belt is transferred onto the recording material, the recording material thickness and surface characteristics, and the recording material conveyance characteristics with respect to the latent image carrier For example, it is possible to effectively prevent image distortion and color misregistration during multiple transfer without considering the above.
[0003]
In this type of image forming apparatus, a belt cleaner is usually provided on the downstream side of the secondary transfer portion of the intermediate transfer belt. This belt cleaner has, for example, a cleaning blade that can be moved toward and away from the intermediate transfer belt, waits at the retract position during each color component imaging cycle, and contacts the intermediate transfer belt after the final color component imaging cycle. It moves to the set position and cleans the residual toner on the intermediate transfer belt.
[0004]
[Problems to be solved by the invention]
By the way, in this type of image forming apparatus, a method of reducing the fixing speed of the fixing device is adopted from the viewpoint of securing the fixing property in the case of special paper such as thick paper and OHP, or in the case of the full color mode. There is.
In order to cope with such a situation, a deceleration mode in which the speed of the intermediate transfer belt is reduced to match the reduced fixing speed may be performed.
At this time, a technical problem has been found that image quality such as image contamination is impaired as compared with the normal mode.
Also, a technical problem has been found that when the image forming cycle of a series of jobs ends and the image forming apparatus is stopped, the image quality of the first sheet of the next job is impaired.
[0005]
The present inventors have investigated the causes of these technical problems. As a result, when the speed of the intermediate transfer belt is suddenly changed during the deceleration mode or when the image forming apparatus is stopped, the phenomenon that the belt cleaner vibrates. I confirmed that it was seen.
Under this circumstance, the toner adhering to the cleaning blade of the belt cleaner at the retracted position is scattered to the intermediate transfer belt side due to vibration, and the intermediate transfer belt is soiled. fear There is.
For example, in the deceleration mode, if toner scattered on the intermediate transfer belt from the belt cleaner side adheres to the image forming area on the intermediate transfer belt, the image quality is impaired.
Further, when the toner scattered from the belt cleaner side onto the intermediate transfer belt adheres to the first image forming area of the next job on the intermediate transfer belt when the image forming apparatus is stopped, 1 of the next job is obtained. The image quality of the first sheet is impaired.
[0007]
The present invention has been made to solve the above technical problems, and Intermediate transfer Provided is an image forming apparatus capable of effectively avoiding image quality deterioration caused by toner scattering from a cleaning unit due to speed change.
[0008]
[Means for Solving the Problems]
That is, according to the present invention, as shown in FIG. Formation Carried Image forming carrier And this statue Formation Carrying body A toner image creating means 2 for forming a toner image in the image forming area; An intermediate transfer member on which an image forming region G and a non-image forming region corresponding to the recording material size and corresponding to the recording material size are provided and a toner image formed on the image forming carrier is temporarily supported; A primary transfer means for transferring the toner image on the forming carrier to the image forming region G of the intermediate transfer body; a secondary transfer means for transferring the toner image transferred onto the intermediate transfer body to the recording material 3; and an intermediate transfer body. Cleaning means 5 for cleaning the residual toner on the upper and lower sides with a cleaning member 5a which can be contacted and separated; The transfer speed of the intermediate transfer member can be switched according to the image forming mode. At least the cleaning member among the parts facing the cleaning means 5 5a In contact area Intermediate transfer member At the position where the non-image forming area of Intermediate transfer member From cleaning member 5a In a separated state Intermediate transfer member of Move Speed Switch control The movement control means 6 is provided.
[0009]
In such technical means, As shown in FIG. The image carrier 1 may be any member as long as it carries a toner image, and may be in any form such as a belt or a drum. as well as Intermediate transfer member Means something .
The toner image creating means 2 is Image forming carrier As long as the toner image is formed thereon, an electrophotographic method, an electrostatic recording method, or the like may be appropriately selected. Also, the image forming area may be uniformly fixed to the maximum size image forming area. However, when image forming efficiency of various sizes other than the maximum size is taken into consideration, the image forming area is used as a recording material. It is preferable to variably set according to the three sizes.
In addition, Secondary transfer means about, Intermediate transfer member In contrast, for example, a transfer roll may be disposed in contact, or for example, a non-contact arrangement may be performed, such as a corotron. In this case, the contact type is not limited to a mode in which the contact type is always in contact as in the black and white mode, but also includes a mode in which the contact type is in contact with and separated from in the full color mode. However, Secondary transfer means As Intermediate transfer member In the mode of contact arrangement so as to be freely contacted and separated, Intermediate transfer member It is preferable to devise so as not to vibrate unnecessarily.
[0010]
The cleaning means 5 may be appropriately selected as long as it has at least a detachable cleaning member 5a. A blade, a fur brush, a roll, or the like is used as the cleaning member 5a. In addition to 5a, for example, a cleaning auxiliary member (not shown) such as a sealing member that keeps the cleaning opening edge airtight may be provided.
Here, the contact / separation timing of the cleaning member 5a is determined by the cleaning member 5a in the normal cleaning cycle. Intermediate transfer member Placed in contact with the Intermediate transfer member However, it may be arranged to retract.
[0011]
Furthermore, among the movement control means 6, “ Switch and control the transfer speed of the intermediate transfer member Means that the toner adhering to at least the cleaning member 5a of the cleaning means 5 is Intermediate transfer member Speed change (V1 → V2 [V1 ≠ V2]) with a vibration that reversely shifts to the side, including a deceleration mode that decelerates from a predetermined speed, and an acceleration that increases from a predetermined speed This includes a wide range of modes, when stopped, and when operation starts.
Therefore, the movement control means 6 basically has Intermediate transfer member of Move Speed Switch control In all cases, the position control as described above may be performed.
However, in the image forming apparatus to be used, for example, Intermediate transfer member of Move Speed Switch control Among them, when the toner scattering due to the vibration of the cleaning unit 5 at the time of the deceleration mode and the stop is remarkable as compared with other conditions, the position control as described above is performed only at the time of the deceleration mode and the stop. Anyway, " Switch and control the transfer speed of the intermediate transfer member The target condition for performing the above-described position control can be selectively set for each image forming apparatus.
[0012]
Furthermore, in the movement control means 6, “at least the contact area of the cleaning member 5 a among the parts facing the cleaning means 5” does not mean the whole area where the whole cleaning means 5 faces but the toner. For the contact area of the cleaning member 5a, which is the most adherent part, Intermediate transfer member The non-image forming area may be arranged to pass through.
However, the area where the toner actually adheres is not limited to the contact area of the cleaning member 5a, but includes the peripheral area. Intermediate transfer member From the viewpoint of more reliably realizing the position control, the movement control means 6 Intermediate transfer member of Move Speed Switch control In this case, at least the cleaning member 5a and A seal member that keeps the cleaning opening edge airtight upstream of the cleaning member 5a in the moving direction of the intermediate transfer member. In the area surrounding the contact area Intermediate transfer member So that the non-image forming area of Intermediate transfer member It is preferable to control the above.
[0013]
Also, by the movement control means 6 Intermediate transfer member Speed switching The timing can be selected as appropriate, Intermediate transfer member The upper image forming area G Along the moving direction of the intermediate transfer member When the tip position reaches at least before the contact area of the cleaning member 5a among the parts facing the cleaning means 5 Intermediate transfer member of Move Speed Switch control What should I do?
[0014]
Furthermore, regarding the stop control by the movement control means 6, Intermediate transfer member The non-image forming area may be positioned at least in the contact area of the cleaning member 5a among the parts facing the cleaning means 5 during the stop operation, and the stop position is not particularly limited.
However, Intermediate transfer member From the viewpoint of dealing with image quality defects accompanying toner scattering from the cleaning means 5 at the start of the operation, Intermediate transfer member The upper image forming area G Along the moving direction of the intermediate transfer member The front end position stops at least before the contact area of the cleaning member 5a among the parts facing the cleaning means 5. Intermediate transfer member May be stopped.
[0015]
As for the position control by the movement control means 6, for example, “ Primary transfer position by the primary transfer means on the intermediate transfer member From Along the moving direction of the intermediate transfer member Opposing to the cleaning means 5 To position If the “at least the distance to the contact area of the cleaning member 5 a among the parts” is set to be equal to or larger than the maximum usable image forming area size, it may be performed uniformly regardless of the size of the image forming area G. .
However, for example, “ Primary transfer position by the primary transfer means on the intermediate transfer member From Along the moving direction of the intermediate transfer member Opposing to the cleaning means 5 To position In the case where “at least the distance to the contact area of the cleaning member 5a among the parts” is set to be smaller than the maximum usable image forming area size, it is of course uniform regardless of the size of the image forming area G. It is possible to do it, but for example Primary transfer position by the primary transfer means on the intermediate transfer member In the situation where the rear part of the image forming area G is passing Intermediate transfer member If you change the speed of Intermediate transfer member If the toner image on the top is distorted (image distortion), Primary transfer position by the primary transfer means on the intermediate transfer member From Along the moving direction of the intermediate transfer member Opposing to the cleaning means 5 To position Depending on the relationship between at least the distance to the contact area of the cleaning member 5a and the length dimension of the image forming area G to be created, Primary transfer means After the last imaging cycle Without switching the transfer speed of the intermediate transfer member It is preferable to determine whether or not to perform a dummy cycle for idling, and to perform position control after performing the dummy cycle in a situation where image distortion occurs.
[0016]
Next, the operation of the technical means described above will be described.
In FIG. 1, the movement control means 6 Intermediate transfer member From cleaning member 5a For example, in the deceleration mode with the Intermediate transfer member In the case where the speed of V is changed from V1 to V2 (V2 ≠ V1), at least the contact area of the cleaning member 5a among the parts facing the cleaning means 5 is used. Intermediate transfer member The non-image forming area (area other than the image forming area G) is positioned Intermediate transfer member To control.
For this reason, Intermediate transfer member The cleaning means 5 vibrates with the change in the speed of the cleaning member 5a of the cleaning means 5 and the like. Intermediate transfer member Even if the toner is reversely transferred to the side, Intermediate transfer member It mainly adheres to the upper non-image forming area and hardly adheres to the image forming area G.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
FIG. 2 is an explanatory view showing an embodiment of an image forming apparatus to which the present invention is applied. In this embodiment, reference numeral 21 denotes a photosensitive drum (latent image carrier) that rotates in the direction of an arrow, 22. Is a charger such as a corotron for charging the photosensitive drum 21 in advance, and 23 is an image of a laser scanning device (ROS) or the like that writes an electrostatic latent image corresponding to each color component on the photosensitive drum 21 based on each color component image information. A writing device (in this example, a beam is attached to the beam from the device), and 24 is a developing device 241 to 244 corresponding to each color of yellow (Y), magenta (M), cyan (C), and black (K). This is a rotary type (rotary type) developing device mounted on a rotary holder 245, and the electrostatic latent image formed on the photosensitive drum 21 is developed by any of the developing devices 241 to 244 to form each color component toner image 100. To do Going on. Reference numeral 25 denotes a drum cleaner that removes residual toner on the photosensitive drum 21 as waste toner.
[0018]
Reference numeral 30 denotes an intermediate transfer belt disposed so as to be in contact with the surface of the photosensitive drum 21, and is stretched around a plurality of (for example, six in the present embodiment) rolls 31 to 36 in the direction of the arrow. To turn to.
Further, a primary transfer device (primary transfer roll in the present embodiment) 26 is disposed on the back side of the intermediate transfer belt 30 at a portion (primary transfer position) of the intermediate transfer belt 30 facing the photosensitive drum 21. The toner image on the photosensitive drum 21 is electrostatically attracted to the intermediate transfer belt 30 by applying a voltage having a polarity opposite to the charging polarity of the toner to the primary transfer roll 26.
[0019]
Here, the tension rolls 31 to 36 of the intermediate transfer belt 30 used in this embodiment are used. about In other words, reference numeral 31 denotes a drive roll provided in the vicinity of the upstream side of the primary transfer portion by the primary transfer roll 26, and 32 denotes the drive roll 31 and the drive roll 31 in order to maintain the posture of the intermediate transfer belt 30 at the primary transfer portion in a predetermined posture. A driven roll (posture holding roll) 33 disposed on the extension line of the primary transfer roll 26, 33 is a tension roll provided on the downstream side of the driven roll 32 to apply a predetermined tension to the intermediate transfer belt 30, and 34 and 35 are provided. A driven roll 36 disposed on the further downstream side of the tension roll 33 is a counter roll (backup roll) which is an element of the secondary transfer device 40 described later.
Reference numeral 39 denotes a roll cleaner for cleaning the peripheral surface of the drive roll 31 and eliminates uneven conveyance of the intermediate transfer belt 30 due to dirt on the surface of the drive roll 31.
[0020]
Furthermore, a secondary transfer device 40 is disposed at the secondary transfer position of the intermediate transfer belt 30 facing the conveyance path of the recording material P such as paper. In this embodiment, the toner of the intermediate transfer belt 30 is disposed. A secondary transfer roll 37 disposed in pressure contact with the image carrying surface side and a counter roll (backup roll) 36 disposed on the back side of the intermediate transfer belt 30 and serving as a counter electrode of the secondary transfer roll 37 are provided.
In this embodiment, the secondary transfer roll 37 is grounded, and a bias having the same polarity as the charging polarity of the toner is stably applied to the backup roll 36 via the power supply roll 38.
[0021]
Reference numeral 41 denotes a belt cleaner that removes residual toner on the intermediate transfer belt 30.
In this embodiment, as shown in FIGS. 3A and 3B, the belt cleaner 41 has a cleaner case 42 that opens to face the toner image carrying surface of the intermediate transfer belt 30, and this cleaner case 42. A cleaning blade 43 that can be brought into contact with and separated from the intermediate transfer belt 30 is provided at the upper edge of the opening, and a film seal 44 that is brought into contact with and separated from the intermediate transfer belt 30 is provided at the lower edge of the opening of the cleaner case 42. The cleaner case 42 is provided with a transport auger 45 for transporting the recovered toner to a recovery container side (not shown).
In the cleaning cycle, the belt cleaner 41 places the cleaning blade 43 and the film seal 44 in contact with the intermediate transfer belt 30 (set to the set position) as shown in FIG. The residual toner 101 is scraped off by the cleaning blade 43 and airtightness is ensured by the film seal 44. On the other hand, during the image forming cycle other than the cleaning cycle, for example, as shown in FIG. The film seal 44 is spaced from the intermediate transfer belt 30 (set to the retract position). In FIG. 3B, reference numeral 102 denotes toner attached to the cleaning blade 43 and the like.
[0022]
Furthermore, in the present embodiment, the recording material conveyance system conveys the recording material P from the recording material tray 50 to the predetermined conveyance path by the feed roll 51, and a registration roll (registration roll) 52 in the conveyance path. Then, the recording material P is temporarily stopped in positioning, and then the recording material P is conveyed to the secondary transfer position at a predetermined timing. The recording material P after the secondary transfer is guided to the conveying belt 53, and this conveying belt 53 It is conveyed to the fixing device 60.
[0023]
In this embodiment, as shown in FIG. 4, the intermediate transfer belt 30 secures an image forming area (not shown) corresponding to the recording material size. In the non-image forming area, a reference mark 71 for generating a reference signal for determining an image writing position and the like is formed, and a predetermined position separated from the intermediate transfer belt 30 corresponding to the movement locus of the reference mark 71 is formed. A mark sensor 72 is arranged.
Here, as the reference mark 71, for example, a highly reflective light reflector or a hole through which light passes is used.
[0024]
Further, in the present embodiment, the image forming control device 80 is constituted by, for example, a microcomputer system (CPU, ROM, RAM, I / O port), and as shown in FIG. A signal from various mode selection switches such as a recording material mode and a detection signal from a recording material size sensor (not shown) and a mark sensor 72 are taken into the CPU via the I / O port, and the CPU is preinstalled in the ROM. Image forming processing program (see FIG. 5), various image forming devices including a photosensitive drum 21 and an image writing device (not shown), a primary transfer device 26, a secondary transfer device 40, a belt cleaner 41, A predetermined control signal is sent to the drive motor 73 of the intermediate transfer belt 30 through the I / O port.
[0025]
Next, an image forming process of the image forming apparatus according to the present embodiment will be described.
As shown in FIG. 5, when the printing is started, the image forming control device 80 first detects the recording material size information in the feeding direction, and then detects yellow (Y), magenta (M), cyan (C), black (K ) Of each color component toner image (each color printing), and each color component toner image is transferred onto the intermediate transfer belt 30.
That is, an electrostatic latent image for each color component of yellow, magenta, cyan, and black is formed on the photosensitive drum 21, and each electrostatic toner is applied with the corresponding color toner of each developer 241 to 244 in the rotary developing device 24. After the latent image is made visible, the image is sequentially primary-transferred to the intermediate transfer belt 30 and the superimposed transfer image of each color component toner image on the intermediate transfer belt 30 is secondarily transferred onto the recording material P. .
[0026]
Thereafter, the image forming control device 80 determines whether or not the special mode is set, and determines whether or not to implement the deceleration mode.
Now, assuming that the recording material P is cardboard, OHP, or the like, the image forming control device 80 determines that it is in the special mode and determines to execute the deceleration mode.
The deceleration mode referred to in this example indicates that the normal mode is reduced to about 60 to 130 mm / sec. When the normal mode is 220 mm / sec.
Next, the image forming control device 80 compares the recording material length Z (feed direction recording material size information) with the reference length L.
Here, as shown in FIG. 4, the reference length L is a region before the region A (see FIG. 3A) surrounding the contact region of the cleaning blade 43 and the film seal 44 of the belt cleaner 41 from the primary transfer portion T1. It is the distance to reach the restriction position B located at.
[0027]
Assuming that Z> L, the image forming control device 80, as shown in FIG. 6, the rear end portion of the image (corresponding to the image forming region G) has passed the primary transfer portion T1, and the front end portion of the image is region Before reaching A, specifically, when reaching the restriction position B, the deceleration mode is executed, and the intermediate transfer belt 30 is decelerated.
In this state, the cleaning blade 43 and the film seal 44 of the belt cleaner 41 are waiting at the retract position as shown in FIG. 3B, but when the intermediate transfer belt 30 is decelerated, the vibration at this time Is propagated to the belt cleaner 41, the toner 102 adhering to the cleaning blade 43 and the film seal 44 is scattered to the intermediate transfer belt 30 side by vibration.
However, the intermediate transfer belt 30 region Since the part corresponding to A is a non-image forming area (an area other than the image forming area G), the scattered toner only adheres to the corresponding non-image forming area of the intermediate transfer belt 30 as described above. It hardly adheres to the formation region G.
Therefore, even if the toner is scattered from the belt cleaner 41 to the intermediate transfer belt 30 side, the scattered toner image carried on the intermediate transfer belt 30 is not disturbed by the scattered toner.
[0028]
When the relationship between the reference length L and the recording material length Z is Z ≧ L, the leading end of the image (corresponding to the image forming area G) has reached the restriction position B as shown in FIG. Under the conditions, the rear end portion of the image is passing through the primary transfer portion T1, and if the deceleration mode is executed for the intermediate transfer belt 30 at this time, image distortion occurs.
Therefore, in the present embodiment, after the idle rotation (dummy cycle) of about one round is performed, in other words, after the primary transfer operation of the final color component toner image is finished, region Before reaching A, specifically, when reaching the restriction position B, the deceleration mode is executed, and the intermediate transfer belt 30 is decelerated.
[0029]
Thereafter, the image forming control device 80 executes the secondary transfer by the secondary transfer device 40, and when this is completed, the leading end of the remaining image (corresponding to the residual toner in the image forming region G) is detected. region Before reaching A, specifically, at the time when the regulation position B is reached, the speed increasing mode is executed, the intermediate transfer belt 30 is returned to the normal speed, and the cleaning blade 43 and the like are brought into contact with the intermediate transfer belt 30. (Contact) and execute the cleaning cycle.
Even when the acceleration mode is executed, the belt cleaner 41 vibrates with the vibration of the intermediate transfer belt 30 and the toner attached to the cleaning blade 43 and the film seal 44 may be scattered to the intermediate transfer belt 30 side due to the vibration. However, even if the toner scatters to the intermediate transfer belt 30 side, the toner only adheres to the non-image forming area of the intermediate transfer belt 30, and the image quality is not particularly impaired.
[0030]
When the cleaning cycle is completed, the cleaning blade 43 of the belt cleaner 41 moves backward from the set position to the retract position.
After this, the tip of the remaining image (corresponding to the residual toner in the image forming area G) region Before reaching A, specifically, when reaching the regulation position B, a brake for stopping is applied to stop the intermediate transfer belt 30.
At this time, if the brake for stopping is applied to the intermediate transfer belt 30, the intermediate transfer belt 30 vibrates, this vibration is transmitted to the belt cleaner 41, and the toner is scattered from the belt cleaner 41 to the intermediate transfer belt 30 side.
However, even if the toner scatters toward the intermediate transfer belt 30, the toner only adheres to the non-image forming area of the intermediate transfer belt 30, and becomes a part that becomes the first image forming area G of the next job. The toner does not adhere.
For this reason, the first image forming cycle of the next job does not start in the state in which the scattered toner adheres to the portion that becomes the first image forming area of the next job, and the image quality of the first sheet does not start. It will not be damaged.
[0031]
Also, region The dimension between A and the restricting position B may be selected as appropriate. In particular, for example, if the intermediate transfer belt 30 running in the normal mode is stopped, the dimension is set substantially corresponding to the braking distance. Even when the intermediate transfer belt 30 is completely stopped, the intermediate transfer belt 30 region The part corresponding to A is still a non-image forming area.
In this case, when the operation of the intermediate transfer belt 30 is started when starting the next job, the belt cleaner 41 vibrates with the vibration at that time, and the toner attached to the cleaning blade 43 and the film seal 44 is caused by the vibration. Although there is a concern that the toner is scattered on the intermediate transfer belt 30 side, even if the toner is scattered on the intermediate transfer belt 30 side, the toner only adheres to the non-image forming area of the intermediate transfer belt 30, and in particular, the image. Quality is not compromised.
[0032]
When the deceleration mode is not performed after the image forming cycle of each color component toner image is completed, the secondary transfer is immediately performed, and then the remaining image (corresponding to the remaining toner in the image forming area G). The tip is region Before reaching A, the cleaning blade 43 or the like is brought into contact with the intermediate transfer belt 30 and a cleaning cycle is executed.
When the cleaning cycle is completed, the cleaning blade 43 of the belt cleaner 41 is retracted from the set position to the retract position as described above, and then the remaining image (corresponding to the residual toner in the image forming area G). The tip is region Before reaching A, specifically, when reaching the regulation position B, a brake for stopping is applied to stop the intermediate transfer belt 30.
[0033]
Further, the usage condition of the belt cleaner 41 used in the present embodiment is changed, and for example, the toner adhesion amount (toner accumulation amount) of the cleaning blade 43 in two image forming apparatus (M / C) models (1) to (2). As a result, an experiment as shown in FIG. 8 was obtained.
In the figure, “film seal F / L” is the free length of the film seal 44 (PET is used in this experiment), “cam speed” is the retract speed of the cleaning blade 43 by a cam mechanism (not shown), “blade” “Adhering toner amount” indicates the toner adhesion amount of the cleaning blade 43 after 10 KCV run, “After cleaning” indicates the toner amount when the toner adhering to the cleaning blade 43 is removed by cleaning, and “upper surface”, “upper and lower surfaces” "Denotes the amount of toner removed from the upper surface or upper and lower surfaces of the cleaning blade 43 after cleaning. “Upper surface adhesion amount” represents the toner accumulation amount on the upper surface of the cleaning blade 43, and “Total adhesion amount” represents the toner accumulation amount on the upper and lower surfaces of the cleaning blade 43.
Here, the “total adhesion amount” is an index corresponding to the toner amount accumulated on the cleaning blade 43 at the retract position, and it is understood that the “total adhesion amount” increases as the “cam speed” increases. %)"reference).
Therefore, if the belt cleaner 41 having a fast retracting speed is used, the retracting operation time of the belt cleaner 41 can be shortened accordingly, and a series of image forming cycle times can be shortened. However, the belt cleaner 41 having a fast retracting speed is preferred. In the image forming apparatus using the toner, it is expected that toner scattering due to vibration appears remarkably. However, if this embodiment is used, image quality deterioration due to toner scattering is not particularly problematic.
[0034]
【The invention's effect】
As described above, according to the present invention, at least the contact area of the cleaning member among the parts facing the cleaning means is provided. Intermediate transfer member At the position where the non-image forming area of Intermediate transfer member With the cleaning member separated from Intermediate transfer member of Move Speed Switch control So that Intermediate transfer member Even if the cleaning means vibrates as the speed changes, and the toner scatters from the cleaning means side, the scattered toner Intermediate transfer member The situation of adhering to the upper image forming area can be effectively prevented.
Therefore, Intermediate transfer member Therefore, it is possible to effectively avoid image quality deterioration due to toner scattering from the cleaning means due to the speed change.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing an outline of an image forming apparatus according to the present invention.
FIG. 2 is an explanatory diagram illustrating an overall configuration of the image forming apparatus according to the first embodiment.
3A is an explanatory view showing a state of the belt cleaner used in the first embodiment at a set position, and FIG. 3B is an explanatory view showing a state of the belt cleaner at a retracted position.
FIG. 4 is an explanatory diagram showing an image formation control system used in the first embodiment.
FIG. 5 is a flowchart showing processing contents of the image forming control system of FIG. 4;
FIG. 6 is a schematic diagram showing an operation process in the case of a small size recording material.
FIG. 7 is a schematic diagram showing an operation process in the case of a large-size recording material.
FIG. 8 is an explanatory diagram showing a change in the toner adhesion amount when the use condition of the belt cleaner used in the first embodiment is changed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Image carrier, 2 ... Toner image preparation means, 3 ... Recording material, 4 ... Transfer means, 5 ... Cleaning means, 5a ... Cleaning member, 6 ... Movement control means

Claims (7)

An image forming carrier on which a toner image is formed and carried,
Toner image creating means for forming a toner image in an image forming area of the image forming carrier;
An intermediate transfer member on which an image forming region and a non-image forming region corresponding to the recording material size and facing the image forming carrier are provided to temporarily carry a toner image formed on the image forming carrier;
Primary transfer means for transferring the toner image on the image forming carrier to the image forming area of the intermediate transfer member;
Secondary transfer means for transferring the toner image transferred onto the intermediate transfer member to a recording material;
Cleaning means for cleaning residual toner on the intermediate transfer member with a cleaning member which can be contacted and separated; and
And can be switched in accordance with the moving speed of the intermediate transfer member to the image forming mode, from the intermediate transfer member at least a non-image forming region of the intermediate transfer member to the contact area of the cleaning member is positioned location of the portion facing the cleaning unit An image forming apparatus comprising: a movement control unit that switches and controls the movement speed of the intermediate transfer member in a state where the cleaning member is separated. The image forming apparatus according to claim 1.
The controlling switch the moving speed of the intermediate transfer member, the image forming, characterized in that the speed varying degrees with vibrations toner adhered to at least a cleaning member of the cleaning means will be reverse transition to the intermediate transfer member side apparatus. The image forming apparatus according to claim 1.
And controlling the switching of the moving speed of the intermediate transfer member, the image forming apparatus characterized by the speed change to the intermediate transfer member is decelerated or accelerated. The image forming apparatus according to claim 1.
When the movement control means switches and controls the movement speed of the intermediate transfer member , at least the cleaning member and the cleaning opening edge upstream of the cleaning member in the movement direction of the intermediate transfer member are hermetically sealed. an image forming apparatus wherein the non-image forming region of the intermediate transfer member to a portion surrounding the contact area of the seal member and controls the intermediate transfer member so as to be positioned to maintain. The image forming apparatus according to claim 1.
Movement control means, the intermediate transfer when the tip position along the moving direction of the intermediate transfer member of the image forming region on the intermediate transfer member reaches the front of the contact region of at least a cleaning member of the portion facing the cleaning unit An image forming apparatus characterized by switching and controlling a moving speed of a body . The image forming apparatus according to claim 1.
Further, the movement control means stops the tip position of the image forming area on the intermediate transfer body along the moving direction of the intermediate transfer body at least before the contact area of the cleaning member among the portions facing the cleaning means. An image forming apparatus for stopping an intermediate transfer member . The image forming apparatus according to claim 1.
The movement control means further includes at least a contact area of the cleaning member in a portion from the primary transfer position by the primary transfer means on the intermediate transfer body to a position facing the cleaning means along the movement direction of the intermediate transfer body. In accordance with the relationship between the distance and the length dimension of the image forming area to be created, a dummy cycle is performed in which the intermediate transfer member is idlely rotated without switching control of the moving speed of the intermediate transfer body after the final image forming cycle by the primary transfer unit. An image forming apparatus that determines whether or not.

Images