JPH034243A - Image forming device - Google Patents

Abstract

PURPOSE:To improve operability by providing a switch which turns on and off the action of a displaying means before and after the image forming action of the device main body. CONSTITUTION:A fluorescent displaying tube 11c is in an on-state at the time of connecting a power source and display is carried out. When an image formation starting key (not shown in diagram) is turned on in this state, the image forming action is started. On the other hand, when the starting key is not turned on, a key switch 11d is turned off and the fluorescent displaying tube 11c is made to be in an off state and the display is turned off. Thus, the image forming action is started only when the fluorescent displaying tube 11c is displayed. Further, by turning on the key switch 11d, when the fluorescent displaying tube 11c whose display has been turned off once is turned on, the displaying control is returned to the state at the time of connecting the power source. Thus, power consumption of the whole device can be cut down, and the operability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an image forming apparatus using an electrophotographic method or the like.

(Prior Art) A conventional image forming apparatus of this type includes a display means, for example, a fluorescent display tube, for displaying information necessary for operating the apparatus.

(Problems to be Solved by the Invention) However, this type of display means is configured to constantly turn on and display when the image forming apparatus main body is turned on, regardless of the image forming operation.

For this reason, when the power is on, the display means lights up and displays regardless of necessity, increasing the power consumption of the entire device more than necessary.

The present invention has been made based on the above circumstances, and an object thereof is to provide an image forming apparatus that consumes less power and has excellent operability.

[Structure of the Invention (Means for Solving the Problems) In order to solve the above problems, the present invention provides a switch means for turning on and off the display means before and after the start of the image forming operation. It is something.

(Function) That is, according to the present invention, the operating state of the display means can be switched on and off at will during a period other than the image forming operation using the above-mentioned means.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 2 shows the external appearance of an electrophotographic image forming apparatus using a semiconductor laser, and FIG. 3 shows its internal configuration. This image forming apparatus (laser printer) is connected to a host system (not shown), which is an external output device such as an electronic computer or a word processor, via a transmission controller such as an interface circuit. When a print start signal is received from the host system, an image recording operation is started, and the image is recorded on paper as a transfer material and output.

This image forming apparatus has the following configuration.

That is, numeral 1 in the figure is a main body of the apparatus, and a main control board 2 is disposed in the center of the main body 1 of the apparatus. and,
An electrophotographic process unit 3 for forming images is arranged behind the main control board 2 (toward the right side in the state shown in FIG. 3), and a plurality of control boards for adding functions are located at the lower front. A control board storage space 5 for accommodating a plurality of sheets of paper 4, and a paper discharge section 6 are formed in the upper front part.

Further, a lower portion inside the apparatus main body 1 is a cassette accommodating section 8 that accommodates a paper feed cassette 7.

As shown in FIG. 2, the paper ejection section 6 consists of a recess formed on the front upper surface of the main body 1 of the apparatus, and the front edge of the paper ejection section 6 is folded over the paper ejection section 6 or has a recess as shown in the figure. A rotatable paper discharge tray 9 that can be unfolded is provided. Furthermore, a notch 9a is formed in the center of the front end of the paper ejection tray 9, and a rotatable U-shaped auxiliary ejection that can be accommodated in the notch 9a or unfolded as shown in the figure. A tray 10 is provided. The size of the paper discharge section 6 can be adjusted according to the size of the paper P to be discharged.

Further, a control panel 11 is disposed on the upper surface of the left frame portion 1a of the apparatus main body located on the left side of the paper ejection section 6, and a manual feed tray 1 is disposed on the rear side of the apparatus main body 1.
2 is installed.

Next, the electrophotographic process unit 3 that performs electrophotographic processes such as charging, exposure, development, transfer, peeling, cleaning, and fixing will be described with reference to FIGS. 3 and 4.

A drum-mounted photoreceptor 15 serving as an image carrier is disposed approximately in the center of the unit accommodating portion, and this photoreceptor 1
5, a charging means 16 made of a scorotron, an exposure section 17a of a laser exposure unit 17 as an exposure means (electrostatic latent image forming means), a developing process and a cleaning process are arranged around the rotating direction of the 5. A magnetic brush type developing means 18 and a transfer means 19 consisting of a scorotron are carried out at the same time.
, a memory removing means 20 consisting of a brush member, and a pre-exposure means 21 are arranged in this order.

Further, inside the apparatus main body 1, paper P fed from the paper cassette 7 via the paper feeding means 22 and paper P manually fed from the manual tray 12 are placed between the photoreceptor 15 and the transfer means 1.
A paper conveyance section 24 is formed that leads to a paper discharge section 6 provided on the upper surface side of the apparatus main body 1 through an image transfer section 23 between the paper transfer section 9 and the image transfer section 23 .

Furthermore, an aligning roller pair 25 and a transport roller pair 26 are arranged on the upstream side of the image transfer section 23 of the paper transport path 24, and a fixing unit 27 and a paper ejection roller pair 28 are arranged on the downstream side.

Further, a pair of conveying rollers 26 is provided. Note that 13 is an aligning switch.

When a printing start signal is received from the host system, the drum-shaped photoreceptor 15 rotates, and the photoreceptor 15 is charged by the charging means 16. Next, the laser beam a modulated in response to the dot image monitor from the host system is operated to expose the photoreceptor 15 using the laser exposure unit 17 including the polygon mirror scanner 30, and an image signal is transferred onto the photoreceptor 15. form an electrostatic latent image corresponding to This electrostatic latent image on the photoreceptor 15 is developed and visualized by the toner t in the magnetic brush D' of the developing means 18.

On the other hand, in synchronization with this toner image forming operation, the paper P taken out from the paper feed cassette 7 or manually fed from the manual tray 12 is fed through a pair of aligning rollers 25 and placed on the photoreceptor 15 in advance. The toner image formed on the paper P is transferred to the paper P by the action of the transfer means 19. Just then,
The paper P passes through the paper transport path 24 and is sent to the fixing unit 27. The fixing unit 27 includes a heat roller 41 containing a heater lamp 40 and a pressure roller 42 pressed by the heat roller 41. The toner image is applied to the paper P by passing between these rollers 41 and 42. Melted and fixed. Then, after this, the paper ejection roller pair 2
The paper is discharged to the paper discharge section 6 via the paper discharge section 8 .

Note that after the toner image is transferred onto the paper P, the residual toner remaining on the photoreceptor 15 is removed by the memory removing means 7 consisting of a conductive brush, and the memory is removed in the next developing step as described above. will be collected.

In addition, in the present invention, in order to simplify the process of conventional electrophotography, a reversal development method is adopted in which the exposed portion is developed, and a method is adopted in which the residual toner t after transfer is removed at the same time as the development. did. At this time, changes in the surface potential of the photoreceptor 15 and the state of the toner t on the photoreceptor 15 are changed as shown in FIG.

That is, the charging means 16 charges the photoreceptor 2 to -5
The toner t is charged to 00V (see (A) in FIG. 5). At this time, the toner t, which has not been completely transferred on the photoreceptor 15 in the previous process, is also charged at the same time.

At this time, it has been found from experimental results that even if the toner t... is removed with a urethane blade or the like, the surface potential is maintained at 80 to 90% or more.

Next, the photoreceptor 15 receives the laser beam a which is modulated in response to the dot image data from the host system and scanned by the laser exposure unit 17 as described above.
The surface potential is attenuated and an electrostatic latent image is formed [(B in Fig. 5).
)reference]. The surface potential of the exposed portion at this time is -50V (room temperature). Here, the photoreceptor 15, the charging means 16, and the laser exposure unit 17 are designed as follows.

The photoreceptor 15 uses an OPC (organic photoconductor) photoreceptor, and as shown in FIG.
, charge transport layer 52 are applied in this order.

The charge generation layer 51 is made of γ-type raphthalocyanine (manufactured by Toyo Ink) and butyral resin in a weight ratio of 1:1 and has a thickness of 061 μm.
It was coated on. The charge transport layer 52 is made of 9-ethylcarbazole-3-carboxaldehyde methylhydrofuzone (ECMP) [manufactured by Kenu Pharmaceutical] and polyarylate (
U-100) manufactured by Unitika] was applied to a thickness of 17 μm at a weight ratio of 0.65. This charge transport layer 5
2 is transparent to visible light and semiconductor lasers, and is located above the charge generation layer 52, so even if toner particles t of 30 μm or less are present on the surface, the photoreceptor 1 is transparent as shown in FIG.
When 5 is exposed to light 55, the diffracted light 56 and the transport layer 52
Due to the reflected and scattered light 57 within the charge generating layer 51, shadows of the toner particles t are hardly formed or are only formed so thin that there is no problem in practical use. However, the diameter of the toner particles t is 3
When the thickness exceeds 0 μm, image defects occur as white spots on a solid black surface. The transport layer 52 may be made of any material as long as it is transparent to the exposure light source and has a carrier transport function, such as a polycarbonate resin in which a pyrazoline derivative is dispersed, or an acrylic resin in which an oxadiazole derivative or an oxazole derivative is dispersed. Alternatively, a triphenylmethane derivative dispersed in polycarbonate resin may be used. Further, if the thickness is not greater than the average particle diameter of the toner t, it will cause image defects. Furthermore, as shown in FIG. 8, the thickness is preferably 30 μm or less in view of residual potential characteristics. In addition, photoreceptor 1
5 basically only needs to have a charge transport layer 52 on the charge generation layer 51, and as shown in FIG. 60 etc. may be used. The photoreceptor 15 used in this embodiment has a photosensitivity of half-decreased exposure of 6.2 erg/cII2 (see FIG. 10). Here, the appropriate value of the amount of laser light is determined based on the following grounds.

This process does not use a dedicated cleaner or an independent process for cleaning, and performs electrostatic cleaning at the same time as development, so that image exposure is performed from above the transfer residual toner t existing on the photoreceptor 15. Therefore, in some cases, a portion where transfer residual toner t exists may be exposed.

Normally, the photoreceptor 1 is used for areas where there is no remaining transfer toner t.
Exposure amount to half the surface potential of 5 (6., 2e in this example)
rg/cm") (D3~43~4 times the amount of light is sufficient for the latent image potential of the image, but (
For example, in Fig. 10, the toner t is 24.8 erg/c12).
acts as a filter, and the photoreceptor 15 is underexposed in that area, resulting in memory generation and defective images.

In other words, if the exposure amount is less than 4 times, a one-dot wide black and white bare line as shown in (a) in Figure 11B or a checkerboard pattern created by exposing every other dot as shown in (a) in Figure 11A In the case of a pattern like this, the 15 photoreceptor process does not require a dedicated cleaner or an independent process for cleaning, as shown in (b) of Figure 11A and B, and electrostatic cleaning is performed at the same time as development. In order to do this, image exposure is performed from above where the transfer residual toner t is present on the photoreceptor 15. Therefore, in some cases, a portion where transfer residual toner t exists may be exposed.

Normally, the photoreceptor 1 is used for areas where there is no remaining transfer toner t.
Exposure amount to half the surface potential of 5 (6.2e in this example)
An exposure amount of about 3 to 4 times erg/cLI2) is sufficient for the latent image potential of the image (for example, 24.8erg/cI2 in Fig. 10), but a few pieces of untransferred toner may clump together. The toner t acts as a filter for a certain portion, and the photoreceptor 15 is underexposed in that portion, resulting in memory generation and a defective image.

In other words, if the exposure amount is less than 4 times, a one-dot wide pair of black and white lines as shown in (a) in Figure 11B or a checkered pattern formed by exposing every other dot as shown in (a) in Figure 11A. In the case of a pattern like a pattern, it is fastened to the photoreceptor 15 and fixed to the terminal 77, as shown in (b) of FIGS. 11A and 11H. The upper terminals 75 and 77 are each covered with terminal covers 78 and 79 so that the parts to which high pressure is applied are not exposed.

On the other hand, the shield case 70 is made of stainless steel with a thickness of 0.3 am, and has a mesh on the side facing the photoreceptor 15, as shown in FIG. 14, and serves as a grid 70a of the scorotron charger. Despite the configuration, the grid 70a is integrated with the side cases 70b and 70c, so that the grid 70a can maintain sufficient accuracy such as its flatness without using any special parts.

Furthermore, since the same bias voltage is applied to both side cases 70b and 70c when corona discharge occurs (described later), the corona current flowing through both side cases 70b and 70c is also reduced, resulting in a charger with good current effect.

Further, the shield case 70 is connected to the anode of a 560V Zener diode 82 (see FIG. 18), and is connected to a charger guide 83 (see FIG. 18) through the cathode of the Zener diode 82. On the other hand, the charger guide 83 is coupled to the ground terminal of the main body.

Therefore, the corona wire 71 is connected to the high voltage transformer (
When a higher voltage (-5 kv) (not shown) is applied through the power supply bin 73, corona discharge occurs in the shield case 70, and current flows through the shield case 70. However, due to the rectifying characteristics of the Zener diode 82, the shield case The potential at 70 rises to 560V and remains constant.

Therefore, the grid 70a naturally becomes -560V, so the surface potential of the photoreceptor 15 located 2 mm away from the grid 70a is kept constant at -500V, which is slightly lower than the potential of the grid 70a. In the figure, when the charger 17 is integrated into the process cartridge 105 (see FIG. 1), which will be described later, the engaged portion 82 (see FIGS. 19 and 20) formed in the process cartridge 105 is This is an engaging portion that engages.

As shown in FIGS. 4 and 16, the laser exposure unit 17 also includes a polygon scanner 32. fθ lens 33. Correction lens 34
．． It is composed of reflection mirrors 35, 36, etc. for scanning the scanned laser beam a to a predetermined position. The lower part of the laser exposure unit 17, that is, the upper and lower sides of the cassette accommodating section 8 are open, and the paper feed cassette 7 is placed forward (in the direction of the arrow in FIG. 3).
The structure is such that it can be removed downwards after being pulled out (
(See Figure 16).

Further, as described above, the developing means 18 employs a reversal developing method and a method in which the residual toner t after transfer is removed at the same time as development in order to simplify the electrophotographic process. There is. As shown in detail in FIGS. 4 and 17, this developing means 18 includes a photoreceptor 15 and a developing roller 92 provided in a casing 91 having a developer storage section 90. , developer storage section 9
A two-component developer consisting of toner (colored powder) t and carrier (magnetic powder) C is housed in the container 0.

Further, the sliding contact portion of the developer magnetic brush D' formed on the surface of the developing roller 92 with the photoreceptor 15, that is, the developing position 9
A doctor 94 for regulating the thickness of the developer magnetic brush D' is provided upstream of the photoconductor 3 in the rotational direction of the photoreceptor 15. Further, the developer storage section 90 includes a first
．． ! Two developer stirring bodies 95 and 96 are accommodated.

Note that the developing means 18 is equipped with a toner replenishing device (not shown) so as to appropriately replenish the developer accommodating portion 90 with toner t.

The developing roller 92 is a magnetic roll 1 having three magnetic pole parts 100, 101, and 102 as shown in FIG.
03, and a non-magnetic sleeve 104 that is fitted onto the magnetic roll 103 and rotates clockwise in the figure. Three magnetic pole parts 100, 101 . of magnetic roll 103 .
102, the magnetic pole portion 101 facing the development position 93 is N
The other magnetic pole parts 100 and 102 are S poles. Further, the angle θ1 between the magnetic pole portion ICl0 and the magnetic pole portion 101 is set to 150″, and the angle θ2 between the magnetic portion 101 and the magnetic pole portion 102 is set to 120″.

The electrostatic charge on the photoreceptor 15 is caused by the potential difference between the mechanical scraping force caused by magnetic brush development using a two-component developer, the charging potential caused by reversal development, and the development bias applied to the magnetic brush D'. At the same time as the latent image is developed, residual toner t is collected mechanically and electrically.

Further, as shown in FIGS. 1, 17, 18, and 19, the developing means 18 includes a photoreceptor 15, a charging means 16, a memory removing means 20, etc., which are integrated into the developing means 18.
It constitutes a process cartridge 105, and one end of the process cartridge 105 can be inserted into and taken out of the apparatus main body 1 via a cartridge insertion/removal handle 110 (see FIGS. 18 and 19). Further, on the other end side, a charging means power supply section 11 consisting of a developing bias power supply section 111, a memory removing means power supply section 112, and a power supply bottle 73 is provided.
3 is provided protrudingly, and this process cartridge 105
When the device is pushed into a predetermined position within the device main body 1, these power feeding portions 111, 112, and 113 are inserted into a power feeding connector provided within the device main body 1.

Further, a foldable handle 115 for carrying is provided on the top side of the process cartridge 105, and a cleaning brush 116 for cleaning the lower roller 25a of the aligning roller pair 25 is attached. Furthermore, as shown in FIGS. 1 and 20, on the other end side of the developing means 18, the developing sleeve 104, the first. A gear group 122 that is connected to the second developer stirring body 95, 96, a winding shaft 121 (see FIG. 17) for winding up the photoreceptor protection sheet 120, etc., and that interlocks with each other.
has been set up. And gear 122a
meshes with a drive gear (not shown) provided on the device main body 1 side, and by driving this gear 122a, each of the above-mentioned rotating members is rotationally driven in a predetermined direction at a predetermined speed. Note that the photoreceptor protection sheet 120 wound around the winding shaft 120 is housed in a guide tube 124 surrounding the winding shaft 120, so that the end portion does not protrude to the outside.

Note that 125 shown in FIG. 20 is a positioning groove for one of the charging means.

Further, 126 shown in FIG. 18 is a process cartridge 1.
05 is a rod for pressing the presence detection switch (not shown), 127 is a toner replenishment port shutter that opens when a toner replenishment hopper (not shown) is attached, and 128 is a shutter spring. Further, 129 is a pin for fixing the photosensitive drum.

As shown in FIGS. 18 and 21, an auto-toner sensor ring 140 consisting of a metal-plated cap is attached to one end of the photoreceptor 15, and the developer concentration can be detected at this portion. It has become. As shown in FIG. 22, this auto toner sensor ring 140 is connected to a doctor blade 94 via a conductive leaf spring 141 made of phosphorus paulownia or the like.
Furthermore, it is connected to the developing sleeve 104 via a conductive leaf spring 142, so that the auto-toner sensor ring 140, the doctor blade 94, and the developing sleeve 104 are at the same potential. In other words, power can be supplied to the auto toner sensor ring 140 without using a dedicated power supply means.

Further, the photoreceptor 1 provided with the auto toner ring 140
5, a flange 145 equipped with a leaf spring 143 and a bush 144 is attached to the other end as shown in FIG. A photoreceptor drive shaft 146 provided on the apparatus main body 1 side is inserted into the photoreceptor drive shaft 145a. Then, the locking tongue portions 143a of the leaf springs 143 engage with the engaged portions (not shown) of the photoreceptor drive shaft 146, so that the photoreceptor drive shaft 146
The driving force is transmitted to the photoreceptor 15.

Further, the transfer means 19 is composed of a scorotron as shown in FIGS. 23 to 26.

A corona wire 151 is stretched inside a shield case 150, and one end of this corona wire 151 is connected to the 23rd
As shown in the figure and FIG. 24, it is connected to a metal fitting 153 screwed to the power supply terminal 152, and the other end is connected to the shaft 155 of the power supply terminal 154 via a tension spring 156 as shown in FIG. . Further, the portion of the shield case 150 facing the photoreceptor 15 has a mesh as shown in FIG. 23, and has a grid 150a.
It consists of

23 and 2 on the power supply terminal 152 side.
As shown in FIG. 6, a grid voltage power supply section 157 and a wire high voltage power supply section 158 are provided.

Next, the memory removing means 20 will be explained.

The memory removing means 20 includes a brush member 160 and a holding member 204 that holds the brush member 160.

The brush member 160 is made of rayon, nylon, acrylic,
The main component is resin such as polyester, which is carbonized with carbon particles, metal powder, phenol resin, etc., or a bundle of conductive artificial fibers in which conductive materials such as stainless steel fibers are dispersed. . This artificial fiber is made by, for example, dispersing an appropriate amount of carbon particles in the resin liquid and extracting it from a nozzle-shaped extraction port. The volume resistivity of the artificial fiber can be freely selected by changing the amount of carbon particles dispersed. Further, the thickness and cross-sectional shape of the artificial fiber can be changed as appropriate depending on the diameter and shape of the extraction port of the nozzle.

It is desirable that the artificial fiber used as the brush member 102 of the present invention has a volume resistivity of 10 to 10 7 Ωcm.

If the deposition resistance is less than 102 Ωc, m, when a voltage is applied to the brush member 102 to electrostatically attract residual toner as described later, a discharge phenomenon occurs between the brush member 102 and the photoreceptor, and the photosensitive layer of the photoreceptor is The problem arises that it destroys the Furthermore, if the volume resistance is greater than 107 ΩCm, even if a voltage is applied to the brush member 160, the untransferred toner on the photoreceptor cannot be electrostatically attracted, and the untransferred toner directly moves to the brush member 160. In order to pass,
The effects of the brush member 160, which will be described later, cannot be obtained.

The artificial fiber used as the brush member 160 of the present invention has a cross-sectional shape as shown in FIG. That is, the artificial fiber has an uneven surface 160a, and the unevenness is substantially continuous in the length direction of the artificial fiber. Therefore, the artificial fiber used in the brush member 160 of the present invention has a large surface area and maintains linear orientation in the length direction. Therefore, when the brush member 160 is brought into contact with the photoreceptor 15, the brush member 102 can come into contact with more of the residual toner on the photoreceptor 15 and will not be bent, which will be described later. Brush member 1
60 and can withstand long-term use.

Moreover, the thickness of the artificial fiber is preferably 1 to 50 deniers. If the denier is less than 1 denier, the artificial fibers may break or easily fall off from the holding member 204, making it impossible to withstand long-term use as the brush member 160 of the present invention. If the denier is larger than 50 denier, even if the artificial fibers are brought into contact with the photoreceptor, the bundle of the artificial fibers will be coarse, resulting in problems such as untransferred toner passing through without making sufficient contact with the brush member 160. , it is not possible to obtain the effects of the brush member 160, which will be described later.

The holding member 204 includes a holding fitting 162 and a backing member 161.
and an auxiliary sheet metal 210. The holding fitting 162 is a plate made of a conductive metal, for example, an aluminum alloy.
One end side is bent in advance to have an abbreviated cross-sectional shape, and extends long in the axial direction of the photoreceptor.

Then, by taking into account the thickness a of the brush member 160 from the central part of the holding fitting 162 in the lateral direction, the plate material is bent around the part displaced toward the other end, and the base of the brush member 160 is inserted between the parts. supports the brush member 160. The brush member 160 is bent into an abbreviated shape between one end and the other end of the holding fitting 162. At this time, considering the thickness a, if the rib is smaller than the thickness a of the brush member 160, there is a risk that the brush member 160 will be cut off when the brush member 160 is sandwiched between plates, so it is desirable that the thickness a be larger.

Further, the relationship between the thickness of the brush member 160 and the thickness C of the holding fitting 162 in a bent state is that the thickness a is 0.5 to 2.
mm, the thickness C is desirably about 2.5 to 4 mm,
If it is out of this range, there will be a problem that the brush member 160 will be easily cut or pulled out when the plate material is bent.

Note that in order to prevent the brush member 160 from coming off, a conductive adhesive may be poured between the brush member 160 and the plate material for reinforcement.

The backing member 161 is provided along the surface of the brush member 160 opposite to the surface that contacts the photoreceptor 15, and is for pressing the free end side of the brush member 160 against the photoreceptor. The length of this backing member in the transverse direction is the length of the brush member 1
By making the length longer than the free end side of the brush member 60, there is also an effect of preventing the brush member 160 from having bending curls. Furthermore, by making the length of the brush member 160 in the longitudinal direction longer than that of the brush member 102, it is possible to obtain the effect of preventing the toner once attracted by the brush member from scattering.

Further, by making the backing member a particularly elastic or flexible resin member such as polyester resin, damage to the photoreceptor can be prevented even if the backing member comes into contact with the photoreceptor.

The auxiliary sheet metal 210 is provided in contact with the backing member on the side opposite to the photoconductor, and is provided in contact with the backing member 161 and the brush member 160.
It is intended to reinforce the

In the present embodiment, the auxiliary sheet metal 210 and the backing member 161 are constructed as separate members, but it is also possible for a - number of members to serve as both. In this embodiment, the brush 160 is made of rayon impregnated with carbon to have a specific resistance of 108 Ω·cm and made into fibers with a thickness of 6D (denier), which are made into bundles of 100 fibers at a density of 82 bundles/1 nch. It is constructed by making it into a satin weave and removing two layers of weft threads. Also, brush 1
60 has a backing member 161 made of a polyester film having a thickness of tmm (about 0.1a+m) on one side, as shown in FIGS. 30 and 33, from the tip of the brush 160.
It is attached to the holding fitting 162 in a state where it protrudes by ll1m (approximately 1.0Imm). And photoreceptor 1
5, θ(1, 5') is mounted upstream of the charging means 16 so that the brush surface contacts the corner at a position 3I1 ml from the tip of the brush 160.

The preferred shape of the memory removal means 20 is a fixed brush shape. That is, when the brush is rotated or moved from side to side, the toner not only scatters, but the rotary type also becomes larger and requires a drive system, resulting in higher costs.

Next, the principles, conditions, etc. of simultaneous development cleaning, transfer, image removal, etc. will be explained, including experimental data.

Main cleaning and simultaneous development process (Cleaning
&Developing Process: CDP
) is important in that it is performed using reversal development. This is because the polarity of the toner and the polarity of the charge are the same, so the charging means 3 does not reverse the polarity of the toner.

On the other hand, as shown in FIG. 34, when a cleaning process is performed using regular development, the following occurs.

In this case, if a negatively charged photoreceptor is used, the polarity of the toner will be positive, but in the charging step, the toner remaining after transfer becomes negative, which is the opposite polarity. Exposure step 3
In FIG. 4B, a portion corresponding to the background (white background) is irradiated with light, but the light usually goes around under the toner, and the potential under the toner in the background portion is also attenuated.

Next, when the unexposed areas are developed using toner of positive polarity, the residual toner transferred on the unexposed areas of the photoreceptor is electrostatically removed, and the pattern to be developed is removed in a negative form, resulting in black negatives and memory. The image becomes defective.

In addition, the negative toner remaining after transfer in the exposed area is not sucked into the developing device, so it remains on the photoreceptor. Furthermore, in some cases, development may occur in which positive polarity toner in the developer is attracted.

In the transfer step (D), the residual toner on the exposed area remains on the photoconductor without being transferred because it has the same polarity as the transfer charger. Therefore, each time a process cycle is repeated, the amount of untransferred toner on the photoreceptor increases. Further, since the positive polarity toner attracted by the residual toner is transferred, an image obtained before one revolution of the photoreceptor drum appears on the white background portion of the transferred image (white positive memory). In other words, in the regular development method, each time a process cycle is repeated, the amount of untransferred toner on the photoreceptor increases, and the occurrence of black negative memory and white positive memory increases. In other words, this is the reason why simultaneous development with cleaning is extremely difficult in regular development, but easy in reversal development.

Further, in this method, since the photoreceptor is cleaned by the developing device, paper waste adhering to the photoreceptor is taken into the developing device. Therefore, in order to form a thin layer of developer on the developing sleeve, there are magnetic component methods in which the developing sleeve and doctor blade must be made as narrow as several hundred microns, and non-magnetic component methods in which the doctor blade slides into contact with the sleeve. In this method, when printing a large number of sheets, paper waste gets trapped between the doctor blade and the developing sleeve, making it impossible to form a uniform developer layer on the sleeve, which tends to cause image defects.

(However, it goes without saying that even a single-component developer can be sufficiently implemented in terms of image quality and frequency of use.) On the other hand, two-component developing method does not have such problems, so even if more than 50,000 sheets are printed, image defects may occur. did not occur at all. In other words, the two-component developing method requires a longer maintenance period for the developing device, and is preferable to this method.

However, in this CDP method, certain process conditions are required to obtain high quality images. FIG. 35 is an explanatory diagram of the contents (terms) used here, in which the photoreceptor 15 is connected to the charging means 16.
The potential when it reaches the developing position 93 while being charged and unexposed is called the charging potential v0, and the potential that has been exposed and attenuated by the exposure means 17 is called the post-exposure potential Ver, and the potential applied to the developing roller 94 of the developing means 18. is called the development bias vb, and the difference between the post-exposure potential V (3r and the development bias vb is the development potential Vb -Vb-Ver, and the charging potential VO and the development bias v
The difference between VCL and b is called the cleaning potential VCL-VO-Vb.

In this embodiment, the photoreceptor 15 uses an OPC for negative charging, but considering a positive charging type, Vb, Ver, Vb -
We will discuss Ver and Vo-Vb as absolute values.

In the first quadrant of FIG. 36, the horizontal axis represents the development potential vb -ver,
Picture @ on the vertical axis! The density measurement and measurement data are plotted, and it can be seen that a developing potential of 100 V or more is required to obtain a good image density of 1.0 or more.

On the other hand, the second quadrant shows the developing potential vb on the horizontal axis and the charging potential VO on the vertical axis, and each plot point represents the memory of the image on the paper P that was generated one revolution before the photoreceptor 15 due to poor cleaning. Here, it has been found that when the developing potential is higher than 300V, a memory with a black pattern on a white background is generated due to poor cleaning (hereinafter referred to as "white background memory"). This is considered to be because, although the image density does not increase even when the development potential becomes 300 V or more, the actual amount of toner t attached increases, and the amount of toner t remaining after transfer also increases at the same time.

Next, regarding the third quadrant, here, the horizontal axis represents the cleaning potential vo-Vb1, and the vertical axis represents the charging potential Vo, and shows how a memory image is generated on the paper P.

Here, if the cleaning potential VCL=Vo-Vb is zero, blank memory will definitely occur due to poor cleaning, and it has been found that at least 50V or more is required.

However, when the cleaning potential increases, positive charges are injected back into the toner t from the developing roller 94, and the toner t, which has changed from negative polarity to positive polarity, is transferred to the unexposed area (uncharged area) of the photoreceptor 15. ), which acts as a filter and reduces the exposure amount of the exposure section 17a, resulting in image defects such as blurring of the exposed image or the appearance of an image from the previous rotation of the photoreceptor 15 as a positive memory in the dot pattern. cause a cause Therefore, it has been found that the maximum cleaning potential is preferably at most 300 ■, although it depends to some extent on the toner t, the carrier C, and their combination.

Furthermore, the resistance dependence of the memory removing means 20 was investigated. A 30φ OPC photoreceptor 15 rotating at a circumferential speed of 36 mm/sec is first subjected to pre-exposure using a pre-exposure device 21, and charged to -500V using a scorotron charger as a charging means 16. is rotated at a rotation speed of 14 Or pm in the forward direction relative to the rotation direction of the photoreceptor 15,
The electrostatic latent image formed by exposure is developed at the same time as cleaning, and is transferred onto paper P by a transfer charger serving as transfer means 19.

After the transfer, the image was passed through a brush 200 fixed to the process cartridge 105, and this cycle constituted one cycle to perform continuous printing and evaluate the transferred image.

Note that this embodiment uses reversal development, and since the transfer charger as the transfer means 19 has the opposite polarity to the charging, the surface potential of the photoreceptor 15 after transfer does not exceed the charging potential, and the charging means 16 has the opposite polarity. Since it is a controlled scorotron, there should basically be no potential fluctuations, but in reality, if the same image is printed for a long time, there will be a difference in the residual potential between the exposed and unexposed areas due to optical fatigue, as shown in Figure M37. Red L was used for the purpose of forced fatigue because density unevenness occurs when printing an image of
ED was used.

The resistance dependence of the memory removal means 20 was investigated and the following results were obtained.

The brush used here is a pile weave brush 170 (No. 38 Diagram A.

38B and 38C) was used. In addition, 1 in the figure
71 is a base fabric weft, 172 is a base fabric warp, and 173 is a pile. Here, the specific resistance of the brush 170 is 20°C, 60% RH.
Tests were conducted under different environments from 100 Ω*cm to 1015 Ω·cm, and as shown in Table 1, those with a resistivity of 10 6 Ω·cm or less were effective for black negative memory on halftone (halftone dot) patterns. However, for practical purposes, a resistance of 10 9 Ω·cm or less was sufficient to remove white positives.

If it is less than 103Ω・am, the photoreceptor is 15. (dielectric breakdown of the photoreceptor occurs), and if the hair falls out and touches the charging means 16, it leaks, and when the charging stops, it becomes solid black in the case of a reversal phenomenon. Therefore, it is preferably 10 Ω·cm to 10 Ω·cm.

Furthermore, it was necessary to apply a positive or negative bias to the black negative memory.

Here, when I tried to transfer the remaining toner t after passing through the brush 170 using a mending tape, as shown in FIG. Although it becomes thinner, there is almost no change and memory still occurs on the image.

However, if the negative bias is of the same polarity as the toner t, the border of the character pattern becomes thinner, but the brush 170 develops the central part of the line of the remaining transfer pattern where there was no toner t, making the character darker overall. It becomes a pattern.

However, this does not appear as memory on the image. If a positive bias is applied, which is opposite to the polarity of the toner t, the boundaries of the character pattern will become thinner, and no memory will occur on the image. The polarity of the toner t is the polarity obtained by *m charging with the carrier C. Here, memory removal brush 170 (160
) does not diffuse the toner pattern of the character characteristics remaining after transfer, and the brush 170 (160) does not diffuse the toner pattern of the remaining transferred characters.
It has been found that the toner t is once electrostatically attracted and then spontaneously ejected onto the photoreceptor 15, changing the adhesion position of the toner t on the photoreceptor 15. Note that if you only want to change the toner position, it may be possible to provide a means to actively diffuse the toner t instead of using the memory removal brush 170 (160), but in that case, the device itself would have to be large. This is undesirable because it also causes problems such as toner scattering. In addition, as a result of a running test with 20,000 image outputs, almost no toner t was accumulated in the brush 170 (i6o).

On the other hand, for a white positive memory in which untransferred toner is poorly cleaned due to transfer failure due to lifting, wrinkles, or folding of the paper, only Ov, float, or positive voltage was effective.

From these results, it was determined that the bias for brush 170 (160) must be positive. Therefore, the positive bias voltage is set to 1
Examining the pattern of residual toner t after changing from 00v to 1ooov and the memory removal effect on paper P1.
It was found that the effect is almost the same above 00V, and that a positive voltage is sufficient. However, if more than +700V is applied, OPC
(Organic, photoconductor) It has been found that a slight defect (possibly a pinhole) in the photoreceptor 15 causes a voltage leak, which in turn creates a burnt hole in the photoreceptor 15. The appropriate voltage is +100 to +700V. This is the range that can be practically used.

In this embodiment, in order to reduce the size and cost of the apparatus, the photoreceptor 15 is made small with a diameter of 30 mm, and the paper P is made more rigid.
Since only peeling is used, the transfer means (transfer charger) 19 is applied to the part where the paper P does not pass, and as shown in FIG.
That part is positively charged from 00 to 1200V.

Therefore, it has been found that the negatively charged toner t adhering to the brush 170 (160) develops the positively charged portion through which the paper P has not passed.

In particular, the toner t adheres to a large extent near the leading and trailing edges of the paper P, and appears as streaks on the image as white positive and black negative memory (see paper spacing traces in Table 4). To prevent this, apply a positive bias to the brush 170 (160), and as shown in the flowchart of FIG.
The power applied to the corona wire 151 of the transfer means 19 is turned off only when the transfer means (transfer charger) 19 is passing under the transfer means (transfer charger) 19.
NL, the problem could be solved by preventing the exposed parts of the photoreceptor 15 before and after the transfer paper P from being positively charged.

Note that although the device of this embodiment can print up to A3 paper,
When printing paper narrower than A3 paper, for example 85 paper, both sides of the paper P on the photoconductor 15 (because the device always feeds the center of the paper P at the same position regardless of the size of the paper P) are positively charged. However, in this case, there is no paper P in this area during printing, so there is no problem at all.

Furthermore, as will be described later, it has also been found that it is preferable for the brush shape to be a satin weave.

Here, the timing of turning on the bias power applied to the brush 170 (160) will be described.

Since a positive voltage (a voltage with a polarity opposite to that of charging) is applied to the brush 170 (160), the photoreceptor 15 is basically charged positively. Therefore, the brush 170 is energized.
If the surface of the photoreceptor 15 that has passed through (160) is not subjected to charging corona by the charging means 16, when that portion passes through the developing means 18, the toner (negative polarity) t of the developer in the developing means 18 will adhere. It ends up turning solid black. Such solid black cannot be cleaned completely and becomes a problem. Therefore, the negative charging by the brush 170 (160) may be changed to a negative charging by the charging means 16. TS-M (third
(see Figure 2), the time from turning on the brush bias power supply to turning on charging must be T, -8 or less. In this embodiment, charging and turning on the brush bias were performed simultaneously as shown in FIG. 41.

This problem also occurs when printing is completed.

Therefore, the discharge of the charging means 16 must not be stopped until the surface of the photoreceptor 15 passes through the charging position when it is turned off. That is, the time for turning off the charging must be longer than TSM.

Next, change the thickness of the fibers of the brush 170 (160) to examine the effect on the memory of the image and the photoreceptor 15 after passing through the brush.
When we examined the residual toner image above, we found that if it was thicker than 100D, it could not be removed in some areas, especially in the vertical lines. 1
Below 00D, no memory occurred, and the dark areas at the boundaries of the transferred residual toner image disappeared. In conclusion, the thickness of the fiber is preferably 100D or less.

In addition, the density of the brush 170 (160) is 1000 fibers/1 nch2 or more in the case of a pile type, and the thickness is 0.
There is no effect unless it is 5+u+ or more, and for satin weave, one bundle of 10 to 1000 fibers is 10 bundles/1 nc.
It has been found that unless the yarn is woven into warp or weft yarns at a ratio of h or more and then made into a brush shape, the memory removal effect will be uneven. The memory removal effect is largely determined by brush resistance, fiber thickness, density, etc., but for practical use of the device, it was found that toner falling (scattering) occurs depending on the shape of the brush and the way it is applied. .

Here, the brush 170 (see FIG. 38) made of Vile weave and 1
100 book fibers with a thickness of 3D are bundled together and a sateen weave brush 16 is used as the warp at a density of 127 bundles per inch.
0 (see Figure 31), the length II A s Thickness W (number of satin weaves), angle θ, contact position RB (32nd
1,000 sheets (A4 landscape) were printed with different sizes (see figure), and the amount of toner t scattered or falling onto the charging means 16 consisting of a scorotron was examined.

As a result, as shown in FIG. 42A, the pile weave brush 17
There was a lot of toner falling on both the tip of the brush 0 and the back of the pile brush 170 shown in FIG. 42B, and the grid of the charging means 16 made of a scorotron was stained black. In addition, the hair sometimes falls out, causing a short circuit with the grid of the charging means 16, resulting in a solid black image.

The brush 160 made of satin weave is not preferably applied in such a way that the tip touches the photoreceptor 15 as shown in FIG. 43, as this causes a lot of toner to fall off and also occasionally leaves gaps between the sheets of paper P.

On the other hand, as shown in FIG. 32, by using the satin brush 160 as a pad instead of a tip, toner dropping was significantly reduced. The optimum application conditions are as shown in FIG. 32, when there is no photoreceptor 15, there is no external force on the brush 160, and the brush 160 is fully extended. If M is the tangent in the direction of the brush to the photoreceptor 15 at the point where it intersects with the outer diameter circle at the PSP point, the brush length flA must be 4 mm or more and the installation angle θ must be 45 degrees or less to prevent toner from falling. has faded.

Further, as shown in FIGS. 32 and 33, the brush 16
A brush 1 is attached to the surface opposite to the surface that contacts the photoreceptor 15 of 0.
Backing film 16 to prevent the hairs of 60 from spreading
1 was installed, toner drop-off did not occur even after 3D printing of 10,000 sheets.

This backing film 161 is insulative, and any elastic material with a thickness of 21 mm or less may be used, such as polyester, urethane, high-density polyethylene, polypropylene, butadiene rubber, butyl rubber, silicone rubber, polyacetal, or fluororesin.

However, the tip of the film 161 needs to protrude as much as or more than the tip of the brush 160 (1.5 square inches in this example), and if it is recessed, there is no effect.

This is because when the fibers are spread out at the tips, the toner t adheres closely to each fiber with a size of several tens of microns, and falls and scatters due to subtle changes in air flow or vibrations.

Further, the photoreceptor 15, the charging means 16, and the memory removing means 20 are integrated into the developing unit 18 (see FIGS. 1 and 18), and these process cartridges 105 The device body 1 is integrated
It can be taken in and out.

Therefore, even if the photoconductor 15 is removed from the apparatus main body 1, the relative positional relationship between them does not change, thereby making it possible to prevent toner from scattering from the memory removing means 20 and deterioration of the memory removing effect. Become.

Further, since it is a mere fixed type, the cost will not change much even if it is discarded together with the photoreceptor 15.

Note that the electrostatic latent image on the photoreceptor 15 is visualized by the toner t of the developing means 18, and then transferred onto the paper P by the transfer means 19.

Here, the following measures have been taken.

The process speed (photoreceptor circumferential speed) in this example was 36 a.
m/sec and a normal copying machine (A4 paper vertically feeds 15 sheets/min, process speed is about 14 Cmm/sec)
It is considerably slower, about 1/4 of the time.

In the case of such a slow process speed, the following problems occur when a corotron charger, which has been conventionally used as a transfer means, is used.

■Since the corona current is small, the voltage applied to the corona wire is low and close to the discharge start point, making it unstable due to dirt and environmental changes.

■The values of the applied voltage or output current of the corona for good transfer of the character part and the solid part (the part where the toner is applied over a wide area) are different, and it is difficult to obtain a high-quality transferred image in both parts.

These causes are attributable to the fact that the transfer time is longer due to the slower process speed.

Basically, toner t can be transferred by applying an electric charge to paper P until the potential of paper P reaches a potential that electrostatically attracts toner t.

Therefore, since the process speed is slow, a suitable transfer current is generated when the voltage applied to the corona wire is about 3.5 to 4 kV, and if it is higher than that, excessive transfer occurs. However, as shown in Figure 44, the voltage of 3.5 to 4 kV is almost the starting voltage for corona discharge, and the stability may vary depending on the temperature, humidity, atmospheric pressure, amount of dirt, etc. I am very unwell.

In addition, in order to investigate the difference in the transfer conditions between the character part and the solid part image of ■, solid characters or a large number of characters were printed within a certain area, a visible image was made with toner t on the photoreceptor 15,
The amount of toner adhering to the photoreceptor 15, both untransferred and after being transferred to the paper P, was collected using a certain area cellophane tape (manufactured by Chiban), and the collected tape was dissolved in a certain amount of toluene to determine the transmittance. By determining iDJ, the transfer efficiency was calculated using the following formula.

Toner adhesion amount after transfer Transfer effect 1 - Untransferred toner adhesion amount X 100 No. 45
The figure shows the process speed 36 arm/
The transfer efficiency of the character (line) image area and the solid area was investigated when the transfer means 19 of the see device was used as a corotron and the voltage applied to the corona wire 151 was changed, and the character area and the solid area were transferred simultaneously. It can be seen that there is no applied voltage that would result in an efficiency of 80% or more. In other words, as long as a corotron is used, it is inevitable that the image density of either characters or solids will decrease.

The reason for this is that, as shown in FIG. 46, which shows the potential and charge movement of the paper P, the paper P is separated from the photoreceptor 15 in the solid area due to the presence of toner t between the paper P and the photoreceptor 15, and Since most of the toner t except for the toner t retains the charge received from the transfer corona, the potential of the paper P hardly decreases, and the toner t is transferred to the paper P by electric force.

On the other hand, since the width of the toner image in the text area is narrow, the charge on the paper P above the toner t is absorbed by the opposite charge on the unexposed part of the photoreceptor 15 next to the toner image, and the potential of the paper P does not rise. .

Therefore, if the solid area is transferred properly, the character area of the paper P
The potential of the transfer layer becomes low, and the transfer efficiency deteriorates. Conversely, if you try to raise the potential of the paper P in the text area, the potential in the solid area will rise too much, and the toner t in the solid area will receive leakage current from the paper P, causing the polarity to reverse, changing from negative to positive, making it difficult to transfer. Become. In other words, excessive transfer occurs.

In order to eliminate such problems, a scorotron charger similar to the charging means 16 was used as the transfer means 19. By using a scorotron charger, a voltage of 5 kV or higher can be applied to the corona wire 151, which not only stabilizes the discharge but also prevents charge jams from occurring due to dirt and the like. Further, since the potential of the transfer paper P in the solid area and the character area can be controlled to be the same potential, a transferred image with good quality in both the solid area and the characters can be obtained.

Figure 47 shows the transfer efficiency of text and solid areas when using Scotron, which was investigated in the same way as when using Corotron, and it is well controlled, and both solid and text are transferred well at the same time. (Transfer efficiency of 80% or more) This shows that a wide area can be obtained. The shape of a scorotron is almost the same as a charged one.

Here, the transfer scorotron opens downward with respect to the photoreceptor 15, but since it is a positive corona, almost no ozone is generated and there is no problem at all, unlike negative charging. Here, the appropriate value of the grid voltage of the scorotron was investigated by determining the transfer efficiency ilJ.

Table 2 shows the transfer efficiency of various types of transfer paper P by changing the grid voltage.

According to this, good transfer (efficiency 8.
It was found that the regions of grid voltage are different (more than 0%).

Therefore, in order to perform good transfer on all types of paper, it is necessary to switch the grid voltage to at least two different voltages depending on the paper.

In this example, it is 1200 V when using envelopes, and + when using other paper.
I decided to use a signal to switch the output of the grid transformer into two stages of 700■. It goes without saying that the grid voltage may be switched in multiple stages depending on the type of paper.

Here, when using a scorotron as the transfer means 19, one of the things to consider is countermeasures against dirt on the grid of the scorotron. Usually, the transfer means 19 is attached below the photoreceptor 15. Therefore, the opening faces upward, and the paper P passes above it. At this time, the toner t on the photoreceptor 15 and paper dust from the paper P inevitably fall onto the transfer means 19. Transfer means 19
If you turn it into a scorotron, you will inevitably need grid 150a.
Toner T and paper powder fell and adhered to the paper, resulting in dozens of sheets.
During printing of tens of thousands of sheets, the grid 150a becomes heavily soiled, the mesh becomes clogged, and transfer defects tend to occur.

Therefore, in this embodiment, the transfer position is set above the photoreceptor 15,
By providing the Scorotron transfer means 19 above it, the opening on the grid 150a side faces downward, thereby preventing the grid 150a from becoming dirty as described above (see FIG. 3).

The transferability was examined by changing the voltage of the Zener diode, varistor, resistor, power source, etc. on the guide plate 180 and the conductive guide roller 25 shown in FIG. 4. As a result, it was found that even in the scorotron, the transferability changes depending on the potential of the guide plate 181 and roller 25.

Table 3 is an evaluation table of the results.

When a scorotron is used, it has been found that when a voltage is applied to the guide members 181 and 180, transfer defects due to excessive transfer tend to occur.

For this reason, as in the past, the guide member 1 of the paper bus for paper P is
Applying a self-bias to 81.180 using a voltage, a resistor, or a constant voltage element causes excessive transfer in scorotron transfer, resulting in bad results.

Rather, the most preferred is ground (earth) or float (electrically isolated). Therefore, in this embodiment, the guide plate 1
81 and roller 25 were connected to ground, and other contact parts were made of insulating material (for example, ABS resin).

Here, photoreceptor 1 unique to simultaneous cleaning and development (CDP)
The types of memory in which the pattern developed one cycle before No. 5 appears on the next image area and the cause of this occurrence will be described.

There are three types of memory: ■Positive black pattern on a white background (white positive); ■Negative pattern on a halftone (black negative) made from a collection of dots or lines; ■Network made from a collection of dot patterns or lines. This is a positive pattern (black positive) on a dotted halftone (see Fig. 48).

The cause of the white positive in (2) is poor cleaning, and the cleaning potential Vc is the difference between the charging potential and the developing bias VB.
This occurs when L is too small.

The cause of the occurrence of black negative memory (2) is due to poor exposure due to the transferred residual toner image.

The black positive memory (3) is caused by the low resistance of the toner when the cleaning potential is too high.

FIG. 49 shows the principle of generation of black negative memory that tends to appear on the halftone halftone pattern of dots or line aggregates, with the vertical axis representing the surface potential and the horizontal axis representing the distance.

(A) shows the surface potential of the photoreceptor 15 in which there is a slight amount of toner remaining after transfer during the charging process (section a), a large amount (section b), and no toner at all (sections c and d).

(b) shows the surface potential when the photoreceptor 15 is irradiated with a laser spot at intervals of every other dot, ccr
Since part d) is a normal exposure, the potential is attenuated approximately equal to the width of one exposure. In part (a), since the amount of toner remaining after transfer is small, the potential under the toner is considerably attenuated by transmitted light, diffracted light, etc., and is close to the potential of the exposed part where no toner exists. On the other hand, there is a lot of toner remaining after transfer (part b)
does not hit the photoconductor portion under the toner and the potential does not attenuate, so the area where the potential attenuates becomes narrower or disappears altogether.

(c) and (d) show the potential diagram when the exposure state in (b) is reversely developed and the pattern on paper P after heat fixing.
There is no toner remaining after transfer (C.

In section d), a toner image is formed in a pattern with approximately the same diameter (width) as the exposed spot diameter (width), but in section b, where there is a large amount of untransferred toner, the area where the potential has attenuated is the exposed spot diameter (width). Because it is narrower, the developed pattern is also smaller or absent altogether. The remaining toner after transfer is then cleaned (recovered in the developing device). Therefore, if an area with a large amount of untransferred toner forms a pattern of letters or numbers, it will result in a negative memory with white areas (■ in Figure 48).
part).

On the other hand, in areas (area a) where residual toner remains after transfer, the potential under the toner is also attenuated or attenuated to some extent, so the toner remains attached without being cleaned, so the pattern after development is not much different from (areas e, d). , a pattern image with approximately the same diameter (width) as the exposure spot is obtained. In addition, even if the potential under the toner is not sufficiently attenuated, if the size of the toner particle is about 1.2, the exposure spot diameter should be the diameter of the toner particle (usually 8 to 1
0/IZ m (400dot/
1 nch), and the layer thickness of the developed toner is thick, so it gets buried during development or fixing, and there is virtually no problem at all.

By the way, as mentioned above, the cause of black negative memory is the filter effect caused by the residual toner after transfer.
For solid solid images, halftone images, and lines of 5 dots (400 dots/inch) or more, black negative memory does not occur by adjusting the amount of laser light, the structure of the photoreceptor, the transmittance of toner, etc.

However, 4-dot lines or less are more likely to occur.

This is particularly noticeable at the edges of lines, and when characters are composed of four dot lines or less, they look like characters with whitish edges.

Here, when we adhesively transfer the pattern of the character image on the photoreceptor 15 to a mending tape (manufactured by 3M), we see that there is no transfer remaining at the boundary between the developed area and the non-developed area, as shown in Figure 50. Too much toner.

FIG. 51 is a cross section taken along the line X-X of the residual transfer pattern shown in FIG. 50, and it can be seen that a large amount of residual transfer toner remains in the boundary area in the form of an 8i layer. Note that 190 shown in FIG. 51 is a tape. Therefore, almost no light passes through this boundary, which causes black negative memory.

This layered remaining transfer toner at the boundaries of characters and line patterns is broken down to create a single layer that does not cause memory. Alternatively, the black negative memory is prevented by removing the laminated portion by electrostatic attraction.

Therefore, the memory removing member 20 having the above-mentioned function is attached to the transfer means 1.
9 and upstream of the charging means 16.

FIG. 53 shows that the memory removing means 20 is attached to the photoreceptor 15.
It is arranged in a non-contact manner.

The brush member 160 constituting the memory removing means 20 and the photoreceptor 15 do not need to be in contact with each other, and as long as they have a gap of a predetermined distance, the above-mentioned effects can be sufficiently obtained. In this case, the voltage is applied to the memory removing means 20 as described above, and the toner remaining on the photoreceptor 20 is electrostatically attracted by the memory removing means 20.

FIG. 56 shows how the memory removing means 20a and 20b are removed from the photoreceptor 1.
A plurality of (two in this embodiment) are provided along the rotational direction of 5. These memory removal means 20a, 20
The configuration of b is the same as described above. The brush members of the upstream memory removing means 20a and the downstream memory removing means 20b may have the same thickness, but
The thicker the thickness of the brush member, the more desirable results can be obtained.

However, the thickness is limited to the range mentioned above.

Further, it is desirable that the upstream memory removal brush 20a has a larger electric resistance as a brush member than the downstream memory removal brush 20b. However, in this case as well, the resistance is limited to the electrical resistance of the brush member described above. Note that the brush members of the memory removal brushes 20a and 20b may be made of different materials.

FIG. 54 shows an example of how the control panel 11 described above is attached to the main body of the apparatus. The control panel 11 comes from the unit lla and is rotatably attached to the frame portion 1a of the main body of the apparatus via a support shaft 11b. The support shaft 11b also serves as a secondary wire passageway that enables electrical connection between the unit 11a and the main body of the apparatus. With this configuration, the control panel can be placed in an upright position with respect to the main body of the apparatus, so that operability and visibility can be significantly improved. The method of attaching the control panel is not limited to the above-mentioned method.
A similar effect can be obtained by being rotatably supported with respect to the main body of the device.

Next, the control panel 11 includes a fluorescent display tube 11C and a key switch lld for turning on and off the fluorescent display tube display. This fluorescent display tube 11c and key switch lid
The operation will be explained with reference to FIG. When the power is turned on, the fluorescent display tube 11c is in an on state and performs display. In this state, press the image formation start key (
(not shown) is turned on, an image forming operation is started. On the other hand, if the start key is not turned on, please turn off the key switch lid.
, the fluorescent display tube is turned off and the display is turned off. In this case, the operation of the cooling fan unit 29 is stopped or decelerated. The image forming operation described above is started only when the fluorescent display tube 11c is displaying. Mat Nikisui Sochi 1
When the fluorescent display tube 1d is turned on, the display of which was previously turned off is turned on, and the display control returns to the state when the power was turned on.

With such a configuration, the power consumption of the entire device can be reduced.

FIG. 57 shows a cleaning blade 300 and the above-mentioned memory removing brush 20 arranged in combination as memory removing means. Cleaning blade 300, thickness 0. An elastic member of about 1mm or 3ml (
For example, the memory removal brush 20 is made of a urethane sheet material) and is provided upstream of the memory removal brush 20 with respect to the rotational direction of the photoreceptor 15 .

The cleaning blade 300 removes residual toner from the photoreceptor 15. A hole 300a is formed in the cleaning blade 300, and residual toner peeled off and removed by the cleaning blade falls downward in the figure through the hole 300a. This falling residual toner is once sucked by the memory removal brush 2o and returned to the photoreceptor, thereby producing the same effect as already described.

Next, a configuration for peeling and transporting the paper P after transfer from the photoreceptor 15 will be described.

As shown in FIG. 3, the photoreceptor 15 and the fixing unit 27
A memory removal brush 20 is provided between the two.

In this embodiment, the polarity of the toner is negative. The transfer charger 19 performs positive discharge, and the paper P that has passed through the transfer charger 19 has a positive polarity charge. On the other hand, in the lower part of the drawing of the paper P passing through, there is a memory removal brush 2.
A holding metal fitting 162 forming a holding member of 0 is located. This holding metal fitting is applied with a positive potential (for example, a bias voltage of about 500 V). Therefore, the electric field generated from the holding metal fitting 162 and the positive charge of the paper repel each other, and 11;P is lifted upward in the figure. .For this reason, the paper P after transfer
is peeled off from the photoreceptor 15 and smoothly transferred to the fixing unit 27.
will be transported to. Note that a sheet metal member may be independently provided in place of the holding fitting 162, and a bias may be applied to this sheet metal member.

FIG. 58 shows the shape of the surface 7b of the paper feed cover 78 detachably provided on the paper feed cassette 7, which rubs against the paper P. The surface 7b has an uneven shape and has a surface roughness of 1
It is 0 μm or more. By having such a configuration,
The paper P contacts only the convex portion of the surface 7b, which is a so-called point contact state, and the contact area between the paper P and the paper feed cover 7a is significantly reduced. Therefore, the generation of frictional electricity between the paper P and the paper feed cover 7a is reduced, and the paper feed cover 7a and the paper P are not attracted by static electricity, so that the paper can be smoothly ejected from the paper feed cassette 7. .

Fig. 58(a) shows an example in which surface 7 is formed into a matte finish.
b) is an example in which the surface 7b is formed into a hairline (unidirectional) shape;
FIG. 58(C) is an example in which the surface 7b is formed in a hairline shape, FIG. 58(d) is an example in which the surface 7b is formed in a hairline shape, and FIG. 58(e) is an example in which the surface 7b is formed in a hairline shape. FIG. 58(f) shows an example in which the surface 7b is formed in a hairline shape and an example in which the surface 7b is formed in a tile shape, and the surface 7b may have any shape.

Next, details of the developing means 18 will be explained with reference to FIG.

In the casing part 91 of the developing means 18, which is close to the optical system unit 34, there is a cleaning member 18c which forms a double structure by pasting an elastic member 18b such as felt to a member 18a such as a malt brain with pressure contact property. is provided. This cleaning member 18c is the optical system unit 3.
4, and when the developing means 18 is taken out of the apparatus main body and when the developing means 18 is inserted into the apparatus main body, the light emitting surface of the optical system unit 34 is slid along the elongated direction. come into contact with Therefore, the optical system unit 34
8, dirt such as scattered toner will be periodically cleaned.

[Effects of the Invention] As explained above, according to the present invention, the operating state of the display means can be switched on and off at will while the image forming apparatus is not operating, so the display means can be turned on and off only when necessary. It is possible to provide an image forming apparatus that can be operated, has reduced power consumption, and has improved operability. .

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a perspective view of a process unit that is the main part of the present invention, FIG. 2 is a perspective view of the overall appearance of the image forming apparatus, and FIG. 4 is a schematic longitudinal sectional front view showing the configuration of the main parts, and FIG. Figure 6 is a cross-sectional view of the photoconductor, Figure 7 is an explanatory diagram showing the irradiation state when toner is attached to the photoconductor, and Figure 8 is a CT
A diagram showing the relationship between environmental conditions and residual potential when changing the L film thickness, Figure 9 is a schematic cross-sectional view of the photoreceptor, and Figure 10 is a diagram showing the relationship between the exposure amount and surface potential of the photoreceptor. Figure 11A is an explanatory diagram for explaining the effect of insufficient exposure when the exposure pattern is a single pine pattern, and Figure 11B is an explanatory diagram for explaining the influence of insufficient exposure when the exposure pattern is one line. Figure 12 is a plan view of the charging means as seen from the grid side, Figure 13 is a front view, and Figure 14 is Figure 12A-
15 is a side view taken in the direction of arrow B in FIG. 13, FIG. 16 is an explanatory diagram showing the state in which the electrostatic latent image forming means is removed, and FIG. 17 is a schematic cross-section of the process unit. 18 is a plan view, FIG. 19 is a side view of one end, FIG. 20 is a side view of the other end showing only the developing means, and FIG. 21 is a drive force transmission of the photoreceptor. 22 is a diagram schematically showing the power supply state to the auto toner ring, FIG. 23 is a partially cutaway plan view of the transfer means as seen from the grid side, and FIG. 24 is the same as that of FIG. 23. 25 is a sectional view taken along line C-C in FIG. 23; FIG. 26 is a sectional view taken along line C-C in FIG. 23;
FIG. 7 is a plan view of the memory removing means, FIG. 28 is a front view, FIG. 29 is a bottom view, and FIG. 30 is a FIG. 23 C-
31 is a perspective view of the satin weave brush constituting the memory removal member, FIG. 32 is a view showing the state of installation, and FIG. 33 is a view showing the state of the backing film of the brush. Figure 34 is a diagram schematically showing the change in surface potential and the state of toner on the photoreceptor according to the process when cleaning is performed simultaneously with regular development, Figure 35 is an explanatory diagram of the contents of the surface potential, and Figure 36 The figure is an explanatory diagram showing the relationship between the development potential and image density, the development potential and charging potential, and the cleaning potential and charging potential. Figure 37 is a diagram showing the state of the potential after exposure. Figure 38A is memory removal. A perspective view of the pile weave brush constituting the member, No. 38B is a partially enlarged view of the pile weave brush, FIG. 38C is a partial cross-sectional view of the pile weave brush, and FIG. 39 is after passing through the brush placement section. FIG. 40 is a diagram showing the surface potential on the photoreceptor after transfer when the transfer corona is continuous. FIG. 41 is a diagram showing the process timing during printing. FIG. 42A 42B is an explanatory diagram of the case in which the tips of the pile weave brushes are used in contact with each other, FIG. 42B is an explanatory diagram in the case in which the belly of the pile weave brushes are used in contact with each other, and FIG. Fig. 44 is a diagram showing the relationship between applied voltage and discharge current during transfer.
FIG. 45 is a diagram showing the relationship between the applied voltage and transfer efficiency for text and solid images by the corotron charger, FIG. 46 is an explanatory diagram showing the potential of the transfer paper and the state of charge leakage, and FIG.
The figure shows the relationship between the voltage applied by the Scorotron charger and the transfer efficiency, Figure 48 is an explanatory diagram showing examples of memory patterns that tend to appear on transfer paper, and Figure 49 shows the potential of the photoreceptor and transfer when black negative memory occurs. Diagram showing the relationship between remaining toner,
FIG. 50 is a diagram showing an example of a pattern remaining after transfer, FIG. 51 is an explanatory diagram showing the state of toner in the section XX in FIG.
Figure 2 is a sectional view of the brush, Figure 53 is an explanatory diagram when the tip of the brush is used without contacting the photoreceptor, Figure 54 is a partially cutaway diagram showing the operating section, and Figure 55 is a display means. FIG. 56 is a sectional view when multiple brushes are used, FIG. 57 is a sectional view when a blade and brush are used, and FIG. 58 is a diagram showing the shape of the paper feed cover surface. be. 15... Image carrier (photoreceptor), 16... Charging means,
17... Exposure means, 18... Developing means, 19...
Transfer means, 20...Memory removal means, 160.170
...brush, t...toner

Claims (1)

[Claims] In an image forming apparatus in which a display means for displaying image forming information is provided on an operation surface of the apparatus main body, a switch means for turning on and off the operation of the display means before and after the image forming operation of the apparatus main body is started. An image forming apparatus comprising: