JP3880259B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile machine that forms an image by electrophotography.
[0002]
[Prior art]
In an image forming apparatus such as a copying machine, a laser printer, or a facsimile, generally, an electrostatic latent image is formed on the surface of a photosensitive drum (image carrier), and toner is attached to the electrostatic latent image and developed as a toner image ( The toner image is transferred onto a transfer material such as paper, and then fixed by heating and pressing. In such an image forming apparatus, toner that has not been transferred to the transfer material (transfer residual toner) or paper dust (a part of paper fibers or paper components) adheres to the surface of the photosensitive drum after the toner image is transferred. is doing. These deposits are removed from the photosensitive drum by a cleaning device and collected.
[0003]
As such a cleaning device, a device that scrapes off deposits from the surface of the image carrier by bringing a cleaning blade (cleaning member) into contact with the surface of the photosensitive drum is well known.
[0004]
There is also a cleaning device that provides an auxiliary device to the above-described cleaning device to further stabilize the cleaning function. For example, as an auxiliary member, a magnetic toner brush (toner supply means) is disposed downstream of the cleaning blade along the rotation direction of the photosensitive drum, and the toner that the cleaning blade scrapes off from the surface of the photosensitive drum by the magnetic toner brush is disposed. Again, it is supplied to the cleaning blade. By this resupply, a substantially constant amount of toner is always supplied to the nip between the surface of the photosensitive drum and the cleaning blade, the friction coefficient of both members in the nip is stabilized, and the cleaning performance is stabilized.
[0005]
[Problems to be solved by the invention]
However, in the image forming apparatus having the magnetic toner brush described above, in a situation where toner adheres to the surface of the photosensitive drum (hereinafter, this adhesion is also referred to as “fusion” together with electrostatic adhesion). There is a problem that the ability to eliminate fusion is low. This is because when the toner adheres to the surface of the photosensitive drum due to conditions such as unevenness on the surface of the photosensitive drum, the magnetic toner brush causes the fused portion to be removed rather than the toner removed at the nip between the photosensitive drum surface and the cleaning blade More toner is supplied to the toner, which is considered to result from the growth of the fusion.
[0006]
It is known that this phenomenon is likely to occur particularly in a high-temperature and high-humidity environment, and in particular, it is known that a talc component contained in a transfer material such as a public postcard promotes this fusion phenomenon. Therefore, when a postcard (acidic paper) manufactured by government is used in a high-temperature and high-humidity environment, the fusing phenomenon is likely to occur.
[0007]
SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of preventing toner from being fused to a photosensitive drum.
[0008]
[Means for Solving the Problems]
To achieve the above object, according to the present invention, a toner image remains on the surface of the first image carrier after the toner image is transferred from the surface of the first image carrier to the second image carrier at the transfer portion. A cleaning device that removes toner, the cleaning device being in contact with the surface of the first image carrier to form a nip and scraping off the toner on the surface of the first image carrier at the nip; A cleaning means having an elastic member, and an upstream side of the elastic member with respect to the moving direction of the surface of the first image carrier, and the toner is attached to the surface of the first image carrier to the nip. In the image forming apparatus having toner supply means for supplying toner, a first mode in which toner is supplied to the nip through the surface of the first image carrier by the toner supply means, and a second mode in which toner is not supplied. Mode and The control unit includes a switching unit that switches from the first mode to the second mode according to the type of transfer material onto which the toner image is transferred and fixed and the number of images formed by feeding the transfer material. It is characterized by switching to.
[0009]
The control unit may switch from the first mode to the second mode when a postcard is selected as the transfer material and the number of fed sheets reaches a set number.
[0010]
Further, the control means, when the number of fed sheets of the postcard selected as the transfer material is equal to or greater than a set number, and the ratio of the number of fed sheets of the transfer material other than the postcard to the postcard is smaller than the set ratio, It is characterized by switching from the first mode to the second mode.
[0011]
The set number of sheets is 500 to 2,000.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on the illustrated embodiments.
[0013]
<Embodiment 1>
FIG. 1 shows an example of an image forming apparatus according to the present invention. 2 is a longitudinal sectional view schematically showing a schematic configuration of an image forming apparatus (for example, a copying machine or a laser printer).
[0014]
The image forming apparatus shown in FIG. 1 includes a drum-type electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 1 as a first image carrier. The photosensitive drum 1 is configured by providing a photosensitive layer such as OPC (organic optical semiconductor) on the surface of a drum base made of aluminum or the like. The photosensitive drum 1 is rotationally driven at a predetermined process speed (eg, 340 mm / sec) in the direction of arrow R1 by a drum drive motor (not shown).
[0015]
The surface of the photosensitive drum 1 is charged by the charging device 2. The charging device 2 shown in the figure is of a scorotron type and is disposed so as to face the surface of the photosensitive drum 1. By applying a charging bias to the charging device 2 from a charging bias applying power source (not shown), the surface of the photosensitive drum 1 is uniformly charged to a predetermined polarity and a predetermined potential.
[0016]
An exposure device 3 is disposed on the downstream side of the charging device 2 with respect to the rotation direction of the photosensitive drum 1 (the direction of the arrow R1). As the exposure apparatus 3, for example, a laser scanner is used. The laser scanner scans and exposes the surface of the photosensitive drum 1 after charging with the laser light L that is on / off controlled in accordance with image information, thereby forming an electrostatic latent image by removing charges on the laser light irradiated portion. To do.
[0017]
A developing device 4 is disposed further downstream of the exposure device 3. The developing device 4 is provided with a developing roller 4a having a magnet (magnetic field generating means) inside. The developing roller 4a frictionally charges the toner 5 stored in the developing container 4b, carries a thin layer on the surface, and conveys it to the developing position facing the surface of the photosensitive drum 1. A developing bias is applied to the developing roller 4a by a developing bias applying power source (not shown), whereby the toner 5 conveyed to the developing position is attached to the electrostatic latent image and developed as a toner image.
[0018]
Here, the toner 5 will be described in detail. The toner used in the present embodiment is a magnetic toner (magnetic toner), and 100 parts by weight of a styrene-butyl methacrylate-dimethylaluminoethyl methacrylate (weight ratio 7: 2.5: 0.5) copolymer, BET. Surface area 5m ² 40 parts by weight of magnetite having a Mohs hardness of 5.5 at a weight of 3 parts by weight and 3 parts by weight of polypropylene having a weight average molecular weight of 15,000 and a boiling point of n-hexane of 20 weight percent were mixed and melt kneaded at 160 ° C. in a roll mill. Then, after cooling, coarsely pulverized with a hammer mill and then finely pulverized with a jet pulverizer. Subsequently, classification was performed using an air classifier, and a black fine powder having a volume average particle diameter of approximately 7.5 μm was obtained as a black magnetic toner.
[0019]
On the other hand, silica fine powder synthesized by dry method (specific surface area: about 130 m ² / G) While stirring 100 parts by weight, 12 parts by weight of a silicone oil having an amine in the side chain (viscosity at 25 ° C., 70 cps, amine equivalent 830) was sprayed, and the temperature was maintained at about 250 ° C. for 60 minutes. The triboelectric charge of the produced treated silica was +130 μc / g. This silica had a Mohs hardness of 6.0.
[0020]
To 100 parts by weight of magnetic toner, 0.4 parts by weight of silica fine powder treated with silicone oil having amine in the side chain and 0.05 parts by weight of polyvinylidene fluoride (PVDF) were externally added to obtain a magnetic toner. .
[0021]
A transfer guide 6 and a transfer separation charger 7 are disposed on the downstream side of the developing device 4 described above. Transfer of paper or the like to the transfer portion T between the transfer separation charger 7 and the photosensitive drum 1 is performed by the transfer guide 6. Material 8 is fed. The transfer separation charger 7 uses corona discharge to transfer the toner image from the photosensitive drum 1 to the transfer material 8 as the second image carrier, and from the photosensitive drum 1 of the transfer material 8 onto which the toner image has been transferred. Separation. Note that the corona discharge (transfer bias) used for transfer has a polarity opposite to that of the toner 5, and the corona discharge (separation bias) used for separation has the same polarity as that of the toner 5. These are respectively applied by a transfer bias application power source and a separation bias application power source (not shown).
[0022]
A cleaning device 9 according to the present invention is disposed on the most downstream side of the transfer portion T along the rotation direction of the photosensitive drum 1, and this cleaning device 9 is placed on the photosensitive drum 1 after the toner image is transferred. The toner remaining in the toner (transfer residual toner) is collected.
[0023]
FIG. 2 shows details of the cleaning device 9. This figure is a longitudinal sectional view (longitudinal sectional view in a direction perpendicular to the generatrix of the photosensitive drum 1) showing the configuration of the cleaning device 9.
[0024]
The cleaning device 9 includes a cleaning unit A and a toner supply unit B in a cleaning container 9a. As will be described in detail later, the toner scraped by the cleaning unit A is collected as waste toner in the main body of the image forming apparatus. The toner is collected in a container (not shown), but a part of the scraped toner is not collected and is supplied to the cleaning means A as a lubricant by the toner supply means B at a predetermined timing.
[0025]
The cleaning means A has a cleaning blade 9b formed of a plate-like elastic member. The cleaning blade 9b is held by a holder 9m that swings about a shaft 9k, and as the holder 9m is urged in the direction of the arrow Rk by a spring (tensile spring) 9c, the photosensitive drum 1 is moved. It is in contact with the surface with a predetermined contact pressure. A linear nip N is formed at the contact portion along the generatrix of the photosensitive drum 1. The nip N is formed on the side of the photosensitive drum 1 (left side in FIG. 2).
[0026]
Accordingly, the untransferred toner adhering to the surface of the photosensitive drum 1 is scraped off at the nip N by the cleaning blade 9b and falls downward due to its own weight.
[0027]
The toner supply means B has a cleaning roller 9e as a toner carrying member. The cleaning roller 9e is disposed on the upstream side of the cleaning blade 9b along the moving direction of the surface of the photosensitive drum 1 and below the cleaning blade 9b. The cleaning roller 9e is a magnet roller in which a magnet is formed in a roller shape, and is rotated in an arrow Re direction opposite to the arrow R1 direction of the photosensitive drum 1 (therefore, the movement between the surface of the photosensitive drum 1 and the surface of the cleaning roller 9e). The direction will be the same at the closest point of both).
[0028]
Further, the cleaning roller 9e is separated without being in contact with the photosensitive drum 1, and a gap a1 (for example, 2 mm) is provided between the surface of the cleaning roller 9e and the surface of the photosensitive drum 1. The toner scraped off by the cleaning blade 9b described above is carried on the surface of the cleaning roller 9e and moved in the direction of arrow Re.
[0029]
A doctor roller 9f is disposed on the left side of the cleaning roller 9e in FIG. 2, and a toner buffer member 9g is disposed further on the left side of the doctor roller 9f. A conveying screw 9d is arranged. The doctor roller 9f is composed of a non-magnetic round bar and rotates in the same arrow Rf direction as the rotation direction arrow Re direction of the cleaning roller 9e. The direction of movement is reversed.) The doctor roller 9f has a low toner conveying capability due to its rotation, and the toner buffer member 9g is inclined downward on the doctor roller 9f side.
[0030]
Accordingly, a concave toner reservoir 9j is formed by the cleaning roller 9e, the doctor roller 9f, and the toner buffer member 9b. A gap a2 (for example, 2.5 mm) larger than the above-described gap a1 (2 mm) is provided between the surface of the doctor roller 9f and the surface of the cleaning roller 9e.
[0031]
A gap 9h is provided between the surface of the doctor roller 9f and the front end of the toner buffer member 9g, and a slit 9i is provided on the base end side of the toner buffer member 9g, so that it accumulates in the toner reservoir 9j. Excess toner among the toner drops from the gap 9h and the slit 9i toward the lower toner conveying screw. The toner conveying screw 9d rotates in the direction of arrow Rd to convey toner to a waste toner collection container (not shown) in the image forming apparatus main body.
[0032]
Next, the operation of the cleaning device 9 configured as described above will be described.
[0033]
The untransferred toner adhering to the photosensitive drum 1 is scraped off by the cleaning blade 9b at the nip N, and drops and adheres to the cleaning roller 9e. The toner adhering to the cleaning roller 9e is conveyed to the doctor roller 9f side by its rotation. Here, the toner is blocked by the toner buffer member 9g and temporarily stays, and then falls from the gap 9h and the slit 9i toward the toner conveying screw 9d. The dropped toner is collected in a waste toner collecting container (not shown) by the rotation of the toner conveying screw 9d in the direction of arrow Rd.
[0034]
The photosensitive drum 1 described above has a peripheral speed of 340 mm / sec in the direction of arrow R1, the cleaning roller 9e has a peripheral speed of 30 mm / sec in the direction of arrow Re, and the doctor roller 9f has a peripheral speed of 3 mm / sec in the direction of arrow Rf. In addition, the toner conveying screw rotates in an arrow Rd direction at an appropriate rotation number.
[0035]
As the cleaning roller 9e and the doctor roller 9f rotate, the toner carried and transported on the surface by the magnetic force of the cleaning roller 9e causes the gap a2 between the surface of the cleaning roller 9e and the surface of the doctor roller 9f as described above. (2.5 mm) regulates the layer thickness on the surface of the cleaning roller 9 e to 2.5 mm. When the cleaning roller 9e further rotates in this state, the toner whose layer thickness is regulated to 2.5 mm is conveyed to the gap a1 with the surface of the photosensitive drum 1, and the surface of the photosensitive drum 1 is based on the fact that the gap a1 is 2 mm. And is coated on the surface of the photosensitive drum 1. The coated toner is supplied to the nip N of the cleaning blade 9b that is in contact with the surface of the photosensitive drum 1 by the rotation of the photosensitive drum 1, and ensures uniform sliding of the cleaning blade 9b.
[0036]
At this time, the toner reservoir 9i described above stabilizes the amount of toner restrained on the surface of the cleaning roller 9e by temporarily retaining an appropriate amount of toner, and finally forms a uniform toner coat on the surface of the photosensitive drum 1. In addition, the amount of toner supplied to the nip N is stabilized, and the uniform sliding property of the cleaning blade 9b is ensured. Thus, the toner reservoir 9i plays an important role in stabilizing the toner coat and preventing the “turning” and “chatter” of the cleaning blade 9b.
[0037]
The rebound resilience of the cleaning blade 9b has a characteristic that changes as shown in FIG. Generally, when the impact resilience of the cleaning blade 9b is low, the response to an impact from the outside of the cleaning blade 9b is low. For example, when there is a protrusion on a smooth plane, the protrusion is directed to the photosensitive drum 1 of the cleaning blade 9b. The abutment portion has a slow deformation speed, and the abutment portion strongly collides with the protrusion and scrapes off the protrusion. Accordingly, fine irregularities on the surface of the photosensitive drum 1 are scraped off by the cleaning blade 9b, and the surface layer of the photosensitive drum 1 is entirely polished.
[0038]
On the other hand, when the impact resilience of the cleaning blade 9b is high, when the cleaning blade 9b hits the protrusion on the surface of the photosensitive drum 1, the contact portion with the photosensitive drum 1 is quickly deformed, so the impact on the protrusion is weak. The contact portion of the cleaning blade 9b gets over the protrusion. In addition, the cleaning blade 9b acts in the same manner on the toner adhering to the surface of the photosensitive drum 1 as well as the protrusions, and the ability of the cleaning blade 9b to eliminate adhesion is low. There is little damage.
[0039]
In this embodiment, in principle, when the photosensitive drum 1 is driven to rotate, the cleaning roller 9e is also rotated, and toner is supplied from the cleaning roller 9e to the nip N of the cleaning blade 9b through the surface of the photosensitive drum 1. . This is the first mode. That is, the first mode is performed during a normal image forming (copying) operation.
[0040]
Further, while rotating the photosensitive drum 1, the cleaning roller 9e is stopped. Thus, the toner is not supplied from the cleaning roller 9e to the nip N of the cleaning roller 9e via the surface of the photosensitive drum 1. This is referred to as a second mode (a fusion elimination mode). Execution of this second mode (fusion fusion cancellation mode) will be described later. Switching between the first mode and the second mode (adhesion elimination mode), that is, the rotation and stop operation of the cleaning roller 9e, is based on information from the operation unit 20 shown in FIG. This is done by controlling the driving means (not shown) by a control device (CPU) 30.
[0041]
FIG. 4 is a perspective view showing a multi-stack general-purpose paper feed tray (hereinafter referred to as a manual feed tray) for feeding a transfer material such as paper in the image forming apparatus described above. The manual feed tray 10 is attached to the outside of the image forming apparatus main body (not shown).
[0042]
The manual feed tray 10 is provided with a movable bottom plate 12 on the rear end side of the bottom surface in the tray main body 11, and a pair of paper width regulating plates 13 </ b> A and 13 </ b> B are installed in front of the movable bottom plate 12. Yes. The sheet width regulating plates 13A and 13B are configured to be movable by a manual operation in a direction orthogonal to the sheet feeding direction (arrow C direction).
[0043]
That is, if one of the sheet width regulating plates 13A and 13B (for example, the sheet width regulating plate 13A) is gripped and moved, the other rack pinion gear mechanism (not shown) provided at the bottom of the tray body 11 The sheet width regulating plate (for example, the sheet width regulating plate 13B) regulates the lateral width of the transfer material to align the width, and also changes the resistance value of a slide volume (not shown) that moves in conjunction with the rack and pinion gear mechanism. Also, it has a function as a transfer material size information (paper type information) detection means for detecting the width of the transfer material.
[0044]
FIG. 5 is a plan view showing an operation unit provided in the upper part of the image forming apparatus (copier).
[0045]
The operation unit 20 is selected by a start key 21 for starting an image forming (copying) operation, a cassette key 22 for selecting a paper feed cassette for feeding each size of transfer material, and a cassette key 22. A display unit 23 for displaying the size of the transferred material, a counter 24 for displaying the number of images formed (copied), a manual feed mode display unit 25 displayed when the transfer material is fed from the manual feed tray, and a postcard mode. Postcard mode key 26, postcard mode display portion 27 displayed when postcard mode is selected, thick paper mode key 28 for selecting the thick paper mode, and thick paper mode display portion displayed when the thick paper mode is selected 29 and the like.
[0046]
Next, the situation in the case of shifting from the first mode described above to the second mode (the fusion elimination mode) in the present embodiment will be described with reference to the flowchart of FIG.
[0047]
When an image is formed (copied) on a postcard, after an operator places a postcard (public postcard) as a transfer material on the manual feed tray 10, the postcard mode key 26 of the operation unit 20 is depressed (step S1). By pressing the start key 21, a postcard is fed (step S2), and a desired image is formed on the postcard by the above-described image forming operation.
[0048]
Then, the counter 24 counts the frequency of the number of fed postcards that are fed to form an image (step S3). When the total number of postcards fed exceeds a preset number (step S4), the first postcard is formed. The second mode (the fusion elimination mode) switched from the mode is performed for 2 minutes (step S5). That is, the driving means (not shown) of the cleaning roller 9e is controlled by the control device (CPU) 30 to stop the rotation of the cleaning roller 9e, and the nip N of the cleaning roller 9e from the cleaning roller 9e through the surface of the photosensitive drum 1 is achieved. Do not supply toner.
[0049]
Then, after the second mode (fusing cancellation mode) is completed, the number of postcards fed by the counter 24 is reset to zero (step S6), and the mode is switched to the normal first mode.
[0050]
In step S4, the set value of the number of sheets fed in the postcard is set to 500 to 2000 sheets according to the execution time of the second mode (fusion-resolving mode), and the second mode (fusion-resolving mode) is set. In the case of performing for 2 minutes, the set value was 1000 sheets. According to the experiment of the present inventor, after feeding 1000 sheets of postcards, the second mode (fusing elimination mode) is performed for 2 minutes before visually recognizing the defect of the image formed on the postcards. In addition, it was possible to prevent toner fusion.
[0051]
As described above, in the present embodiment, when the number of postcards fed (number of images formed) exceeds the set value, the second mode (the fusing cancellation mode) is performed, whereby the toner on the photosensitive drum 1 is discharged. Fusion can be prevented.
[0052]
In the present embodiment, the predetermined number of sheets set in advance is fixed, but may be changed according to the temperature and humidity environment, or according to the postcard size.
[0053]
The counter for the number of postcards may be held by the nonvolatile memory regardless of whether the power is turned off, or may be entered at the same time when the counter is reset by turning the power off and on. In this latter case, the second mode is usually entered once every morning by turning on the power supply. However, as described above, the rebound resilience of the cleaning blade 9b becomes low at low temperatures. The effect of eliminating the wear can be further expected.
[0054]
In this embodiment, the second mode is forcibly entered when the number of postcards fed (number of images formed) exceeds a predetermined number. However, for example, when the number is exceeded during the image forming operation. The second mode may be entered after the image forming operation is completed.
[0055]
Further, regarding the selection of the postcard mode, it is possible to determine that the postcard is a postcard from the information on the detection of the lateral width when the postcard is set between the paper width regulating plates 13A and 13B of the manual feed tray 10. In this case, even if the operator forgets to press the postcard mode key 26, a flowchart for surely shifting from the first mode to the second mode (the fusion elimination mode) is executed.
[0056]
Further, when there is a mode (for example, a potential control mode or an automatic charging cleaning mode) that needs to be performed between sheets until the next image forming operation or during the image forming operation, downtime can be reduced. In this case, it is preferable to give a certain width to the predetermined number.
[0057]
In general, the size of a public postcard is 100 mm × 148.5 mm, but four sheets of this postcard are commercially available with a size of 297 mm × 200 mm. In this case, there is no problem if the operator depresses the postcard mode key 26, but it cannot be determined that the A4 size (297 mm × 210 mm) is detected by the lateral width detection by the manual feed tray 10. In addition, a method using a paper detection sensor in a paper passing path to determine the length of the transfer material in the paper feeding direction is known. In the present invention, approximately four A4 sizes and four official postcards are spelled. By applying to the detection of a difference of 10 mm, it is possible to judge even when four postcards are spelled.
[0058]
<Embodiment 2>
FIG. 7 is a flowchart in the case of shifting from the first mode described above to the second mode (the fusion elimination mode) in the second embodiment of the present invention. This embodiment will also be described using the cleaning device 9 of FIG.
[0059]
In the present embodiment, in the flowchart of the embodiment shown in FIG. 6, the counter 24 indicates the frequency of the number of sheets of plain paper fed when plain paper other than postcards is fed and the image forming operation is performed. Count (steps S7, S8).
[0060]
Even if the number of postcards fed exceeds the predetermined set number in step S4, if the number of plain papers fed is larger than the postcard in step S9 (postcard: ratio of plain paper in the set ratio of plain paper) Is larger than a preset value), the second mode is not executed. The set ratio of postcard: plain paper is set to 1: 1, for example.
[0061]
In step S9, if the postcard has a larger number of plain papers fed (postcard: the ratio of the postcards is larger than the set value in the set ratio of plain papers), the number of postcards fed in step S4 is larger. Since the predetermined number of sheets has been exceeded, the second mode (the fusion canceling mode) switched from the first mode is performed for 2 minutes (step S5). That is, the driving means (not shown) of the cleaning roller 9e is controlled by the control device (CPU) 30 to stop the rotation of the cleaning roller 9e, and the nip N of the cleaning roller 9e from the cleaning roller 9e through the surface of the photosensitive drum 1 is achieved. Do not supply toner.
[0062]
Then, after the second mode (fusing cancellation mode) ends, the counter 24 postcards, the number of plain paper fed is reset to zero (step S6), and the mode is switched to the normal first mode. According to the experiment of the present inventor, it was possible to prevent toner fusion by feeding plain paper as much as the number of postcards fed.
[0063]
As described above, in the present embodiment, when the number of postcards fed (number of images formed) exceeds the set value and the postcard: plain paper set ratio is larger than the set value, By performing the second mode (the fusion elimination mode), it is possible to prevent toner fusion on the photosensitive drum 1.
[0064]
【The invention's effect】
As described above, according to the present invention, the first mode in which the toner is supplied to the nip between the surface of the image carrier and the elastic member of the cleaning device and the second mode in which the toner is not supplied are set in the transfer material. By switching according to the paper type and the number of sheets to be passed, it is possible to prevent toner fusion on the surface of the image carrier.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to a first embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view showing the cleaning device in the first embodiment.
FIG. 3 is a graph showing the relationship between temperature and the rebound resilience of a cleaning blade.
FIG. 4 is a perspective view showing a manual feed tray.
FIG. 5 is a plan view showing an operation unit.
FIG. 6 is a flowchart in the case of switching from the first mode to the second mode (fusion fusion cancellation mode) in the first embodiment.
FIG. 7 is a flowchart in the case of switching from the first mode to the second mode (fusion fusion elimination mode) in the second embodiment.
[Explanation of symbols]
1 Photosensitive drum (first image carrier)
2 Charging device
3 Exposure equipment
4 Development device
7 Transfer separation charging device
8 Transfer material (second image carrier)
9 Cleaning device
9a Cleaning container
9b Cleaning blade
9e Cleaning roller (elastic member)
10 Bypass tray
13A, 13B Paper width regulating plate
20 Operation unit
26 Postcard mode key
30 Control device (control means)

Claims (4)

A cleaning device for removing toner remaining on the surface of the first image carrier after the toner image is transferred from the surface of the first image carrier to the second image carrier at the transfer section; Cleaning means having a plate-like elastic member that contacts the surface of the first image carrier to form a nip and scrapes off the toner on the surface of the first image carrier at the nip; and An image forming apparatus including a toner supply unit disposed on the upstream side of the elastic member with respect to a moving direction of the surface of the image carrier and supplying toner to the nip by attaching toner to the surface of the first image carrier. In the device
Control means for switching between a first mode in which toner is supplied to the nip via the surface of the first image carrier by the toner supply means and a second mode in which toner is not supplied;
The control means switches from the first mode to the second mode according to the type of transfer material onto which the toner image is transferred and fixed and the number of images formed by feeding the transfer material.
An image forming apparatus. The control means switches from the first mode to the second mode when a postcard is selected as the transfer material and the number of fed sheets reaches a set number.
The image forming apparatus according to claim 1. The control means is configured such that when the number of sheets fed for the postcard selected as the transfer material is equal to or greater than a set number, and the ratio of the number of sheets fed for other types of transfer materials to the postcard is smaller than the set ratio, Switching from the first mode to the second mode,
The image forming apparatus according to claim 1. The set number is 500 to 2000.
The image forming apparatus according to claim 2, wherein the image forming apparatus is an image forming apparatus.

Images