JPH0677166B2 - Image forming device - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an improvement in an image forming apparatus such as a laser printer.

[Technical background of the invention and its problems]

In a copying machine or laser printer that uses an electrophotographic recording process, since the photoconductor as an image carrier is repeatedly used, the powder image developed on the photoconductor is transferred to the transfer material during the process of repeatedly using the photoconductor. Between the transfer means to be transferred onto the photosensitive member and the electrostatic latent image forming means for charging and exposing the photosensitive member to form an electrostatic latent image, and cleaning the photosensitive member for cleaning transfer residual powder on the photosensitive member. Means are arranged.

Conventionally, a laser printer has a configuration as shown in FIG. That is, the photoconductor 2 arranged in the center of the main body 1
The laser beam 5 uniformly charged by the charging charger 3 and scanned by the scanner 4 is focused and exposed on the photoconductor 2 by the Fθ lens 6, and the power is turned on as in the case of the semiconductor laser beam.・ When turned off, the electric charge of the photoconductor 2 is exposed and discharged, and an electrostatic latent image is formed. The electrostatic latent image on the photoconductor 2 is developed by the developing device 7 having a developing roller to which an appropriate bias is applied. The developed powder image is transferred to the transfer material P by the transfer charger 8.
The fixing device 9 fixes the transfer material P. On the other hand, the transfer residual powder that is not transferred onto the transfer material P by the transfer charger 8 and remains on the photoconductor 2 is removed from the photoconductor 2 by the cleaning blade 11 of the cleaning device 10. In this way, the cleaned photoconductor 2 is decharged by the charge removing lamp 12, and is charged again by the charging charger 3, so that the above-described image forming process can be continued. The transfer material P is taken out from a paper feed cassette 13 mounted on the lower part of one side of the main body 1 through a take-out roller 14 and its tip inclination is corrected by an aligning roller 15, and then transferred to the photoconductor 2. It is fed to the transfer portion formed between the transfer charger 8 and the photoconductor 2 at the image forming timing. And
The transfer material P on which the powder image is transferred by the function of the transfer charger 8 is peeled from the photoconductor 2 by the peeling charger 16 and sent to the fixing device 9, and then provided on the other side of the main body 1 via the paper discharge roller 17. It is designed to be discharged to the tray 18 that has been set.

Further, FIGS. 2, 3 and 4 show a conventional example when viewed from the process of repeatedly using the photoconductor. (1) → (2) → (3) → (4) → (5) in FIG.
→ (6) → (1) is the charged portion of the electrostatic latent image on the photoreceptor,
This is a mold for adsorbing and developing a powder having a polarity opposite to that of the charged electric charge, and is a process of repeatedly using a photoconductor in a regular development process.
(1) → (2) → (3) → (4) → (5) → in FIG.
In (6) → (1), a bias is applied to the developing roller at the electrostatic latent image discharging portion of the photoconductor to induce or inject electric charges into the one-component powder, and thereby the charged one-component powder is discharged. It is a mold for adsorbing and developing, that is, a process of repeatedly using a photoreceptor in a one-component reversal developing process. As is clear from the above example, in order to repeatedly use the photoconductor, it has been necessary and indispensable to remove the transfer residual powder on the photoconductor after the transfer process. Actually, in the regular development process of FIG. 2, when the cleaning step (5) is omitted and the static elimination step is performed directly, that is, (1 ′) →
In the process of repeatedly using (2 ′) → (3) → (4) → (6 ′) → (1 ′), the transfer residual powder is charged in the charging step (1 ′) and then exposed. Even when the charged powder remaining in the exposed portion is subjected to the developing step (3), since the residual potential of the photoconductor and the developing bias are almost the same, the charged powder is not cleaned during the developing step and the next transfer step ( In 4), the image is transferred to the transfer member and causes image deterioration such as background fog and background stain. Further, even in the reversal development process using the one-component powder shown in FIG. 3, when the cleaning step (5) is omitted and the charge removing step is performed directly from the transfer step, that is, (1 ′) → (2 ′) →
(3) → (4) → (6 ′) → (1 ′) → In the process of repeatedly using the photoconductor, after the exposure (2 ′), the transfer residual charged powder remaining in the charging portion of the electrostatic latent image. In the developing step (3), the developing bias V is set to be substantially equal to the surface potential V ₀ of the charged portion of the photoconductor, so that the body remains uncleaned, and as in the case of FIG. It is transferred to the transfer member in the transfer step (4). Obviously, this also becomes a factor of image deterioration. Therefore, in the photoconductor repeated use process as shown in FIGS. 2 and 3, it is essential to provide the photoconductor cleaning process between the transfer process (4) and the charging process (1). However, the provision of such a cleaning device firstly requires that the cleaning device be installed, and accordingly, the space volume must be increased, and thus the recording device must be increased accordingly. Give rise to. Secondly, a mechanical stress such as a cleaning member such as a cleaning blade is pressed against the photoconductor and rubbed against the photoconductor to damage the photoconductor or to adsorb powder or the like onto the photoconductor. Film forming to cause deterioration of the image. In order to overcome these drawbacks, the cleaning device is omitted, and the developing device that takes charge of the developing step in the first rotation by changing the developing bias in the second rotation, changing the developing bias in the second rotation during the image forming process, This time, something that works as a cleaning tool has been created. Figure 4 shows
This figure shows the process of repeatedly using the photoconductor.
In FIG. 4, the photosensitive member makes about one rotation at the stages of (1) → (2) → (3) → (4) → (5), and at the next about one rotation, (5) →
The cleaning process of (6) → (1) is performed.
In FIG. 4, in the charging step (1), the photoconductor is uniformly charged to have the surface potential V ₀ . Exposure is performed in the exposure step (2) to form an electrostatic latent image. In the developing step (3), a developing roller biased to a potential approximately the same as or slightly larger than the residual potential of the exposure / discharge portion of the photoconductor adsorbs powder having a polarity opposite to the electrostatic charge to the charged portion of the electrostatic latent image for development. To do. In the transfer step (4), the developed powder image is transferred to a transfer member by a transfer charger. After that, in the neutralization step (5), the photoconductor is electrically neutralized by the neutralization light and the neutralization charger. Here, the photoconductor makes one revolution. After that, the bias V of the developing roller is set in the range of 0 <V <V ₀ . Here, the developing roller is transformed into a cleaning unit, and the transfer residual powder on the photoconductor is removed from the photoconductor. In this way, a two-rotation one-record image is generated. However, in such a repeated use process of the photoconductor, the circumference of the photoconductor must be at least the length of one recording image (because the circumference of the photoconductor is longer than the length of one recording image). If it is shorter than this, when the leading edge of the one-recording image on the photoconductor reaches the developing roller position, the trailing edge of the one-recording image on the photoconductor is still in the developing process, and the developing roller can act as a cleaning means. However, the transfer residual powder on the tip of one recording image on the photoconductor is not cleaned from the photoconductor. Therefore, the peripheral length of the photoconductor, that is, the outer diameter must be increased. In addition, since one of two rotations must be used as a cleaning step, the usage efficiency of the photoconductor is extremely low at 50%. Therefore, there is a problem that the recording speed must be slowed down, and there is a problem that two bias power supplies must be prepared in order to change the bias of the developing roller.

Further, even in the image forming apparatus of the reversal development process using the two-component developer, the cleaning process is provided between the transfer process and the charging process as shown in FIG. Cleaning the photoconductor.

[Object of the Invention]

The present invention has been made based on the above circumstances, and an object of the present invention is to provide an image forming apparatus capable of preventing scratches and film forming of an image bearing member such as a photoreceptor and film forming, and enabling downsizing of the apparatus. It is the one we are trying to provide.

[Outline of Invention]

In order to achieve such an object, the present invention provides an image forming apparatus in which an image is formed by performing charging, exposure, development, transfer and cleaning by one rotation of the photoconductor and repeating image formation by rotating the photoconductor. Charging means for charging the photoconductor to a specific polarity, exposing means for irradiating the photoconductor charged by the charging means with light to form an electrostatic latent image on a portion irradiated with the light, An electrostatic latent image formed by being exposed by the exposing unit has an accommodating portion that is provided so as to face the body and that accommodates a developer having the same polarity as the charging unit charges the photosensitive member. The image is visualized by electrostatically adhering the developer contained in the accommodating portion to the electrostatic latent image, and at the same time, the developer attached to the unexposed portion of the photoconductor is separated from the surface of the photoconductor. Developing / cleaning means for collecting and collecting in the accommodating portion By applying a bias voltage to the developing / cleaning means, the developer adhering to the unexposed portion of the photoconductor is directed toward the developing / cleaning means, and the developing / cleaning is performed on the exposed portion of the photoconductor. Bias voltage applying means for generating an electric field that directs the developer from the means, transfer means for transferring a visible image on the photoconductor onto a recording medium, and the photoconductor after the transfer by the transfer means. And a brush that is provided in sliding contact with the surface to loosen the transfer residual developer adhering to the photoconductor, and develops the transfer residual developer on the photoconductor loosened by the brush.
It is configured to be collected in the collecting section by a cleaning means.

Example of Invention

The present invention will be described below with reference to an embodiment shown in FIGS. FIG. 5 shows a laser printer as an image forming apparatus. In the figure, reference numeral 20 denotes a main body, and a drum-shaped photosensitive body 21 as an image carrier is provided in the main body 20, and a charging charger 22, laser exposure is provided around the photosensitive body 21 along the rotation direction thereof. Beam irradiator of device 33,
A developing device 24, a transfer charger 25, a peeling charger 26, and a charge eliminating lamp 27 are sequentially arranged.

The laser exposure device 23 scans a laser beam 28 oscillated from a laser oscillator (not shown) with a laser scan motor 29 and irradiates the photoconductor 2 through the Fθ lens 30, the first mirror 31, and the second mirror 32. It is supposed to do. The developing device 24 has a structure including a first developing roller 33 and a second developing roller 34.

On the other hand, a cassette 35 is mounted in the lower portion of the main body 1 so that the transfer materials P are sequentially taken out one by one through the take-out roller 36. The transfer material P taken out by the take-out roller 36 is provided on the tray 38 provided on the upper portion of the main body 1 via a conveying path 37 formed by bending the peripheral surface of the photoconductor 21 along the rotation direction into an L-shape. It is supposed to be carried out to.

On the upstream side of the transport path 37, a pair of aligning rollers 39a,
39b, and a fixing device 40 and a pair of discharge rollers 41a and 41b on the downstream side. Further, before and after the aligning roller pair 39a, 39b, there are aligning roller front guide pairs 42a, 42b and pre-transfer guide pair 43a, 43b, and before and after the fixing device 40, a fixing device front guide 44 and a discharging roller front. Guide pairs 45a, 45b are provided. A pre-transfer sensor 46 is arranged corresponding to the pre-transfer guide pair 43a, 43b, and a discharge roller front sensor 47 is arranged corresponding to the discharge roller front guide pair 45a, 45b.

Further, the aligning roller front guide 42b, the aligning roller 39b, the pre-transfer guide 43b, the transfer charger 25, the peeling charger 26, and the fixing device front guide 44 are rotatable frames about a support shaft 48 (not shown). It is attached to the main body 1 and is displaced to the side of the maintenance opening 49 formed in the main body 1 as shown by a chain double-dashed line.

In the figure, reference numeral 50 is an access door that opens and closes a maintenance opening 49 formed facing the conveyance path 37, and is configured to be capable of being largely rotated outwardly about a support shaft 51 as a fulcrum as shown by a two-dot chain line. Has become.

In addition, the discharge roller front guide 45a and the discharge roller 41a
Is attached to a cover 53 pivotally supported by the main body 1 via a support shaft 52, and is pivotally displaced as indicated by a two-dot chain line.

The peripheral speed of the photoconductor 2 is 133.3 mm / sec, the diameter of the photoconductor 2 is 78 mm, and the laser power on the photoconductor 2 is 3.5 mW.

Further, in this image forming apparatus, the circumferential length of the photoconductor 2 is shorter than the longest image length along the rotation direction of the photoconductor 2 of one continuous recording image, and the image on the surface of the photoconductor 2 is made shorter. The transfer area is made larger than the image forming area to completely cover it.

Next, the operation of this device will be described. When the print command is transmitted to the apparatus, first, the drive motor rotates and each part of the apparatus starts to move. At the same time, the charger 22 and
The static elimination lamp 27 is turned on. In this way, the laser beam 28 scans the photoconductor 21 uniformly charged by the charging charger 22 with the scanner 29, so that the photoconductor 21 is negative (Ne
gative) electrostatic latent image is formed.

Now, assuming that the rotation speed of the photoconductor 21 is ω radian / sec, and the phase difference between the charging charger 22 and the first developing roller 33 is θ ₁ radian, the leading end portion of the electrostatic latent image is the first development after θ ₁ / ω second. roller
Reach 33. At this time, the first developing roller 33 and the second developing roller 33
The developing bias V is applied to the developing roller 34. The developing bias V is about half the surface potential V ₀ of the unexposed portion of the photoconductor 21 V ₀
It is set to / 2 (0 <V <V ₀ ). Therefore, the same polarity as the charging polarity, that is, charged colored powder (toner) is adsorbed to the exposed portion of the electrostatic latent image formed by being exposed by the laser light 28, and the electrostatic latent image The powder is not adsorbed to the unexposed portion, that is, the negative electrostatic latent image is developed by the first and second developing rollers 33 and 34. On the other hand, in synchronization with the movement of the electrostatic latent image on the photoconductor 21, the transfer material P is taken out from the cassette (transfer material container) 35 by a roller.
It is sent out toward the aligning roller pair 39a, 39b by 36. Further, the transfer material P and the electrostatic latent image are registered and moved to the image transfer position by rotating the aligning roller pair 39a, 39b at a preset timing. When the transfer material P reaches the image transfer position, that is, when θ ₃ / ω seconds (where θ ₃ is the phase difference between the first developing roller 33 and the transfer charger 25) after the development bias V is applied, The transfer charger 25 and the peeling charger (transfer material neutralizing charger) 26 are simultaneously turned on and off. In this way, electric charges are applied from the back surface of the transfer material P, and the potential of the transfer material P is lowered.
The upper developed powder image moves onto the transfer material P. After that, the transfer material P is neutralized by the peeling charger 26 of the AC charger biased to 1 KV and peeled off from the photoconductor 21, and then it is moved up along the fixing device front guide 44 and held by the heating roller of the fixing device 40. It Here, the powder image of the transfer material P is melted and fixed on the transfer material P. After that, the transfer material P is further nipped by the pair of discharge rollers 41a and 41b, is discharged outside the apparatus, and is stacked on the tray 38.

On the other hand, a part of the powder image transferred to the transfer material P remains on the photoconductor 21. The behavior of the transfer residual powder on the photoconductor 21 will be described along the process of repeatedly using the photoconductor 21 in FIG. According to the above description, each process is (1) →
(2) → (3) → (4) and the transfer process (4) is progressed. Here, a method of repeatedly using the photoconductor 21 of the apparatus of this embodiment will be described in the case where the printing operation of another sheet is further performed from the transfer step (4). Almost most of the powder image reverse-developed on the photoconductor 21 in the transfer step (4) (transfer efficiency of about 80%) is transferred to the transfer material P. However, as shown in the figure, a part of the powder remains on the photoconductor 21 and reaches the charge eliminating step (5). Here, almost all the adsorbed charges of the photoconductor 21 are discharged. Thus, in the charging step (1), the photoconductor 21 and the residual powder on the photoconductor 21 are uniformly charged. However, the experimental results shown in FIGS. 7 and 8 revealed the following. In other words, when the powder layer developed on the photoconductor 21 at a density of D = 1.3 or so is charged on the photoconductor 21 from the top, most of the charges pass through the powder layer and reach the surface of the photoconductor 21. The fact is that they are uniformly charged. FIG. 7 is a schematic view of the experimental apparatus, in which a photoconductor 21 is formed by a two-component developing roller 60 with a bias applied to + 400V.
Shows a state in which black toner is uniformly attached until D = 1.3. Then, the charging layer 61 uniformly charges the powder layer on the photoconductor 21. Next, the surface potential of the photoconductor is measured with a surface electrometer A from above the powder layer. This is the value shown on the horizontal axis of the diagram in FIG. Further, thereafter, the powder layer on the photoconductor 21 is completely removed by the cleaning blade 62, and the surface potential of the photoconductor 21 without the powder layer is measured by the surface electrometer B. This is the value on the vertical axis in the diagram of FIG. When the potential on the surface electrometer A is + 700V, the potential on the surface electrometer B is about + 500V. Therefore,
In this state, the surface potential of the powder layer is about + 200V. However, in practice, it is known that the photoreceptor 21 is charged to about −100 V due to frictional charging between the Se of the photoreceptor 21 and the urethane rubber of the cleaning blade 62. The electric potential becomes about 100V. That is, it can be seen that even if the powder layer is deposited on the photoconductor 21 at a density of D = 1.3, even if the powder layer is charged from above, almost all the charged electric charge is transferred to the surface of the upper photoconductor 21. Further, the density of the transfer residual powder is about 20%, which is low, as in the present embodiment, because the transfer efficiency is about 80%. Therefore, even if the residual powder layer on the photoconductor 21 is charged as in the present embodiment, the photoconductor is not charged.
21 can be uniformly charged, and most of the charged charge wraps around under the residual powder layer. Next, returning to the process of repeatedly using the photoconductor 21 shown in FIG. 6, the charged photoconductor 21 is exposed in the next exposure step (2). In this case, it is possible that the transfer residual powder described above is present in the exposed portion. Therefore, solid development is uniformly performed on the uniformly charged photoconductor 21 (density D = 1.
3) Then, change the transfer charger 25 strength to change the transfer efficiency.
Photosensitive member when exposed to laser after being charged on both sides to
The surface potential of 21 was investigated. The results of this experiment are shown in FIG. The condition at this time is 75 drum potential after charging and before exposure.
0V, development density of photosensitive drum D = 1.3, development bias 400V, drum sensitivity; half exposure 1.5μJ / cm ² , laser power; 5.6μJ
/ cm ² (drum surface) As shown in Fig. 9, transfer efficiency is approx.
At 70% or more, the surface potential of the photoconductor 21 drops to about 80V. This is exactly the same as the residual potential of the photoconductor 21 during normal exposure. That is, it is understood that when the transfer efficiency is 70% or more, the transfer residual powder layer on the photoconductor 21 does not adversely affect the exposure. Therefore, it can be seen that in the exposure step (2), the presence of the transfer residual powder in the exposed portion does not have a bad influence on the formation of the electrostatic latent image. Thus, the next developing step (3) is reached. Here, based on the experiments of FIGS. 7, 8 and 9 described above, and also in the actual print recording experiment, the following was confirmed.
In the two-component reversal development process as in this embodiment,
The transfer residual powder existing in the charging portion of the electrostatic latent image is removed from the photoconductor 21 in the developing step (3), and the electrostatic latent image is exposed.
The powder charged to the same polarity as the charge is adsorbed to the discharge part. That is, it was confirmed that the photoconductor 21 was cleaned at the same time as the development of the charged latent image. The reason for this is as follows. First, in the charging step (1), the photoconductor 21 was uniformly charged to + V ₀ . After this, in the exposure step (2), even if there is a transfer residual powder layer in the exposed portion, the surface potential of the exposed portion of the photoconductor 21 drops to the residual exposure potential, as can be seen from the explanation of FIG. There is. On the other hand, in the unexposed area, most of the charged electric charges are uniformly adsorbed on the surface of the photoconductor 21 below the transfer residual powder layer, as shown in the experiments of FIGS. 7 and 8. It is known and the surface potential of this unexposed part is + V ₀ . Here, the developing roller biased to approximately V = V _0/2 (0 <V <V ₀ ).
Photoconductor 21 on which an electrostatic latent image has been previously formed by 33, (34)
The surface of is rubbed. Therefore, the unexposed electrostatic latent image
In the charging section, an electric field is generated from the photoconductor 21 toward the developing roller 33 (34). In this electric field, the transfer residual powder of the unexposed portion described above is placed, and since it is charged with the same polarity as the charging polarity itself, it is separated from the surface of the photoconductor and the developing roller side 33, Move to (34). This is the cleaning action of the photoconductor 21.

In this embodiment, since the first developing roller 33 and the second developing roller 34 are provided, the above-mentioned cleaning action of the photoconductor 21 is executed quite completely. Seen from the first developing roller 33, the second developing roller 34 is
It can also be seen as a cleaning aid.

On the other hand, in the exposure / discharge section of the electrostatic latent image, the developing roller 33, (3
An electric field is generated from 4) toward the photoconductor 21. In the two-component developer of this embodiment, the carrier is held on the developing roller 33, (34) by the magnetic field force of the developing roller 33, (34), and the powder is frictionally charged with this carrier to be charged to It is electrically adsorbed on the carrier surface by the image charge () of the carrier. This charged colored powder is the developing roller 33,
Placed in the electric field from (34) to the photoconductor 21,
It moves from 33, (34) toward the exposing / discharging portion of the photoconductor 21, and is electrically attracted to the exposing / discharging portion by the mirror image charge () of the base of the photoconductor 21. That is, the electrostatic latent image is developed. Thus, in the method of repeatedly using the photoconductor 21 of the apparatus of this embodiment, the photoconductor is cleaned simultaneously with the development. Therefore, the transfer residual powder is not transferred to the transfer material P in the transfer step and does not cause the background fog or the background stain of the printed image.

Moreover, in this embodiment, unlike the cleaning of the photosensitive member by the cleaning blade or the fur brush to electrically remove the transfer residual powder from the photosensitive member, the photosensitive member 21 may be adversely affected such as mechanical damage and film forming. Not only is the cleaning means itself removed from the image forming apparatus (electrophotographic recording apparatus) without increasing the diameter of the photoconductor 21, it is also possible to make the shape of the apparatus compact.

Next, the stop operation of each element of the apparatus after the completion of printing one sheet will be described. Fig. 10 shows the image formation process for 1-sheet printing,
It shows the ON-OFF timing of each component of the drum static elimination process after the final printing after that. When the image forming process for printing one sheet is completed, that is, when the laser exposure for printing one sheet is stopped, the charging charger 22 is turned off with a slight delay. When θ ′ ₁ / ω seconds have passed since the charging charger 22 was turned off, that is, when the trailing end of the charging portion reaches the position of the second developing roller 34, the developing bias becomes OF.
F will be done. Here, θ ′ ₁ is the charge charger 22 and the second
This is the phase difference of the developing roller 34. (See FIG. 5) Therefore, the photoconductor 21 is not rotated any more and is not developed on the photoconductor 21. Furthermore, (θ ₃ + θ ₁ −θ ′ ₁ ) / ω
After a lapse of seconds, the transferred image for one sheet is completely transferred, so the transfer charger 25 is turned off. Where θ ₃
Is the phase difference between the first developing roller 33 and the transfer charger 25. However, the photoconductor 21 continues to rotate, keeps the peeling charger 26 ON for at least 2π / ω seconds or more, and after the peeling charger 26 is turned OFF, θ ₂ / ω seconds or more have passed, and then the motor and the charge removal are started. Turn off lamp 27. In this final drum static elimination process, the photoconductor 21 has a discharge polarity and thus is completely neutralized, and the image deterioration factors such as image blur caused by the residual charge are removed. In addition, the motor and charger 2
2, the discharge lamp 27 is turned on almost at the same time, but the developing bias does not turn on until the charged portion of the photoconductor 21 reaches the first developing roller 33, and therefore the developing bias is not applied to the uncharged portion. It is not developed in areas other than the image transfer area. That is, in the present embodiment, since image formation is performed only on the image transfer area at the start of printing and at the end of printing, an excessive powder layer is not formed on the photoconductor 21 that has passed the transfer process. It is possible to always obtain a good image without adversely affecting the image forming process for printing, that is, without adversely affecting the printed image.

Furthermore, a process when the transfer material P is jammed inside the apparatus will be described. In this embodiment, the pre-transfer guide pair 43a, 43b
A sensor 46 that detects that the transfer material P has passed through the inside.
And the time difference between the signals sent from the sensor 47 that detects that the transfer material P has passed through the pair of guides 45a, 45b of the discharge rollers and the time interval set by a preset timer, and transfer in the apparatus. The jam signal is generated by detecting whether or not the material P is jammed. As soon as the jam signal occurs, start the motor and
All the constituent elements shown in the figure are stopped and a jam is displayed on the operation panel. The jammed transfer material P is removed from the apparatus by the jam display. First, the access door 50 pivotally supported via the support shaft 51 obliquely below the photoconductor 21 is moved from the side surface of the photoconductor 21 by an arrow. (A) Rotate in the direction to open the maintenance opening 49, and further to the frame (not shown) pivotally supported via the support shaft 48 substantially below the photoconductor 21, the aligning roller front guide 42b, aligning The assembly unit 59 incorporating the roller 39b, the pre-transfer guide 43b, the transfer charger 25, the peeling charger 26, and the fixing device front guide 44 is rotated in the direction of the arrow (B) to remove the jammed transfer material P from the inside of the apparatus. Then, again, the jam signal is released by setting the assembly unit 59 and the access door 50 and inputting a reset signal. As described above, according to the present embodiment, the transport path 37 for the transfer material P is formed in the L shape so as to surround the photoconductor 21 in the transport direction of the transfer material P, and The access door 50 is located on the side surface of the photoconductor 21, and is configured to rotate and release about a support shaft 51 obliquely below the photoconductor, and further, the fixing device front guide 44 and the transfer charger 2 are provided.
5, the assembly unit 59 including the peeling charger 26, the pre-transfer guide 43b, the aligning roller 39b, the aligning roller front guide 42b, and the like is integrated, and rotates about the support shaft 48 located substantially below the photoconductor 21. Since the transfer material transporting path 37 is largely opened, the jam processing is extremely easy. The shape of the transfer path 37 for the transfer material P is achieved by a new method of repeatedly using the photosensitive member 21, that is, development and simultaneous cleaning. By the way, the device that has been jammed in this way and released the jam signal,
Again, the motor, the charger 22 and the static elimination lamp 27 are SW-O
N, and the developing bias is turned on again after θ ₁ / ω seconds.
In this way, the photosensitive member 21 is rotated by SW-ON of the charging charger 22 for at least 2π / ω seconds or more, and the developer powder images not transferred by the jam of the transfer material P and remaining on the photosensitive member 21 are the first and the second. 2 The developing roller 33, 34 removes the photosensitive member 21 and cleans it. Further, a charger 22 and the developing bias from the SW-OFF is SW-OFF to θ _'1 / ω seconds. Thus, if there is no print command, the rotation of the motor is stopped after the drum static elimination process is completed. If there is a print command, it goes without saying that the image forming process for printing one sheet shown in FIG. 10 is continued. Anyway, even if the transfer material P is jammed in this way,
The untransferred powder layer on 21 is completely removed and is prepared for the next recording printing, so that the printed image is not adversely affected by background fog and background stain.

Now, according to this embodiment, the transport path 37 for the transfer material P, which is described separately, is used.
Is L-shaped so as to surround the photoconductor 21 along this traveling direction, the discharge direction of the transfer material P is positioned obliquely above the photoconductor 21, and the transfer material P is shown in FIG. Tray
It is supposed to be loaded in 38. In this way, the transfer material P and the insertion direction of the cassette 35 into the main body 1, the processing direction of the transfer material P discharged outside the main body 1, and the determination / reading direction of the contents are matched with each other. It will have an ideal shape as a component of the system equipment.

As shown in FIG. 5, the discharging roller 41a rotates in the direction of the arrow (c) together with the discharging roller front guide 45a to open the conveyance path to facilitate the removal of the jammed transfer material P.

The present invention is not limited to the above embodiment. That is, in the above embodiment, the electrostatic latent image developing device has the first developing roller 33 and the second developing roller 34, and in the electrostatic latent image developing and cleaning step, the unexposed portion of the photoconductor 21 is exposed. The ability to remove residual toner after transfer and the ability to develop powder on the exposed area have been made even more effective. However, when the first developing roller 33 is regarded as the developing / simultaneous cleaning means, the second developing roller 34 can be regarded as a cleaning assisting means for further enhancing the cleaning ability of the first developing roller 33. Thus, instead of the second developing roller 34, for example, a fur brush 65 shown in FIG. 12 is rotated, and the surface of the photoconductor 21 is rubbed to scatter the transfer residual powder adhering to the photoconductor 21, The first developing roller 33 is also partially scraped off.
Thus, it is possible to remove the transfer residual powder of the unexposed / charged portion more effectively. Further, in this case, as compared with the embodiment, unlike a metal component such as a magnet or a sleeve like a two-component developing roller,
Because you can use a fur brush wrapped around a paper core,
Compared to the case where a cleaning step is provided between the transfer step and the electrostatic latent image forming step as in the conventional example, the cost can be reduced and the removed powder can be collected and processed in the developing device. It is possible to prevent problems such as the scattering of powder, which can be seen in the above.

Now, a method of removing light from the photoconductor 21 will be described. In the embodiment, there is a photo static elimination process between the transfer process and the charging process, but this photo static elimination process may be arranged between the developing process and the transfer process as shown in FIG. Of course. As can be seen from the repeated use of the photoconductor in FIG. 6, in the electrophotographic recording apparatus using the reversal development process, (1) → (2) → (3) → (5 ′) → in FIG.
Even with the method of repeatedly using the photoconductor 21 in (4) → (1), the memory of the charging potential on the photoconductor 21 can be removed.
In other words, the powder adhesion part where the photo-electrification is disturbed, that is, the developing part is already exposed and discharged in the exposure step, and the powder is adhered to the unexposed / charged part,
This is because the powder is not attached to the unexposed / charged portion, so that the electric charge is completely discharged in the static elimination step (5 '). By disposing the charge eliminating step (5 ') between the developing step and the transferring step in this manner, the following advantages exist as compared with the present embodiment and the conventional example. In the reversal development process, the area of the unexposed and undischarged portion of the background is overwhelmingly larger than that of the development area. For this reason, development occurs in which the peeling of the transfer material P from the photoconductor 21 immediately after the transfer process is deteriorated by the influence of the residual charge of the photoconductor 21. However, as shown in FIG. 13, by providing the photo-eliminating step before the transferring step, there is an advantage that such a deteriorating factor of the transfer material P can be removed in advance, and the photo-erasing step is applied to any other part. There is an advantage that it is possible to reduce the volume of the apparatus while improving the performance of the image forming apparatus without the need to arrange the apparatus.

Further, in the present embodiment, the semiconductor laser beam as the exposure light beam is focused on the photoconductor 21 and is scanned / recorded in the axial direction of the photoconductor 21. Of course it is possible. For example, as is a well-known exposure method, an LED array may be used instead of the laser beam, and this beam may be projected onto the photoconductor 21 using a SELFOC lens or the like.

In addition, it goes without saying that the present invention can be variously modified and implemented without departing from the spirit of the present invention.

〔The invention's effect〕

As described above, according to the present invention, development and cleaning can be performed simultaneously. For this reason, conventionally, it is necessary to provide an exclusive cleaning device after the transfer and collect the developer to clean the surface of the photoconductor, but the exclusive cleaning device can be eliminated. Therefore, it is possible to prevent the damage to the photoconductor and the film forming, which have been conventionally caused by the dedicated cleaning device, and to realize the downsizing of the device. Further, in the present invention, the untransferred developer is once loosened by a brush provided in sliding contact with the surface of the photoconductor, and the loosened developer is collected by the developing / cleaning means. Therefore, the developer on the photoconductor can be reliably and stably collected by the developing / cleaning means.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a conventional image forming apparatus, FIGS. 2 to 4 are explanatory views showing different conventional image processes, and FIGS. 5 to 11 show an embodiment of the present invention. FIG. 5 is a schematic sectional view of the entire image forming apparatus, FIG. 6 is an explanatory view showing the image forming process, FIG. 7 is a schematic view of an experimental apparatus for process investigation, and FIG. 8 is a toner layer. Showing charge injection characteristics to the surface of the photoconductor, FIG. 9 shows exposure characteristics of the photoconductor through the residual toner on the photoconductor, and FIG. 10 shows the photoconductor after the image forming process and printing. FIG. 11 is a diagram showing a charge eliminating process, FIG. 11 is a diagram showing a photoconductor cleaning process after the jam is cleared when the transfer material is jammed, and FIGS.
The drawing is a schematic configuration diagram showing another embodiment different from the present invention. P ... Transfer material, 21 ... Image carrier (photoreceptor), 24 ... Developing means (developing device), 65, 66 ... Cleaning assisting means.

Continuation of the front page (56) Reference JP 54-109842 (JP, A) JP 54-12843 (JP, A) JP 54-115233 (JP, A) JP 53-29135 (JP , A)

Claims (2)

[Claims] 1. A charging, exposing, and
In an image forming apparatus in which an image is formed by performing development, cleaning, and transfer, and image formation is repeated by rotating a photoconductor, a charging unit that charges the photoconductor to a specific polarity, and the photoconductor charged by the charging unit. Exposure means for irradiating light onto the surface to form an electrostatic latent image on the light-irradiated portion, and an electric charge having the same polarity as the charging means for charging the photoreceptor, which is provided so as to face the photoreceptor. An electrostatic latent image formed by being exposed by the exposing unit is electrostatically attached to the electrostatic latent image by the developer having an accommodating portion for accommodating the developer. By making the image visible, the developing / cleaning means for separating the developer adhering to the unexposed portion of the photoconductor from the surface of the photoconductor and collecting it in the accommodating portion, and applying a bias voltage to the developing / cleaning means. By doing so, Bias voltage applying means for causing the developer adhering to the exposed portion toward the developing / cleaning means, and generating an electric field in the exposed portion of the photoconductor such that the developer is directed from the developing / cleaning means, A transfer unit that transfers a visible image on the body onto a recording medium, and a transfer residual developing unit that is provided in sliding contact with the surface of the photoconductor between the exposing unit and the developing / cleaning unit, and that is attached to the photoconductor. An image forming method comprising: a brush for disentangling the agent and a part for scraping the agent, and the transfer residual developer on the photoconductor disentangled by the brush is recovered by the recovery unit by the developing / cleaning means. apparatus. 2. The image forming apparatus according to claim 1, wherein the brush is a fur brush.