JPH0467158A - Color picture forming device - Google Patents

Abstract

PURPOSE:To make the surface of the image carrying body of a color picture forming device completely cleanable so as to improve the durability of the cleaning blade used for the cleaning by imparting an emergency stop controlling function which sets the device to an initialized state with an emergency stop signal to a controlling means. CONSTITUTION:When an emergency stop signal is inputted from an emergency stop key, a control unit 13 stops image exposing and developing operations and actuates a destaticizer 8. Then a blade 32 is brought into contact with a developed red toner image section on a photosensitive drum 1 under a pressure and starts to remove toner adhering to the drum 1 at the moment when the leading edge of the red toner image passes through a cleaning device 9. Accordingly the toner of the toner image section acts as a roller or lubricant when the blade 32 is brought into contact with the drum 1 and the occurrence of a bounding phenomenon can be prevented. Therefore, good color images can be obtained, because the surface os the image carrying body is cleaned completely, and the durability of the blade 32 can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a color image forming apparatus, such as a color copying machine or a color printer, which completes one image by repeating an image forming process a plurality of times.

Conventional technologyColor image format that forms multicolor images such as color copying machines
In general, an image forming apparatus is designed to obtain a desired multicolor image by repeating an image forming process multiple times to form a plurality of monochrome images of different colors.

For example, in color copying machines that use electrophotography,
Separate the original into three colors and repeat the image forming process of [original exposure - charging - image exposure - development - transfer - cleaning] three times, or repeat the image forming process four times, including creating a black image, and transfer. It reproduces the color image of the original on paper. In addition, without performing transfer each time, [Original exposure - Charged image exposure -
A method in which multiple image forming units are arranged in series and each unit is A method is used in which a transfer paper is moved while sequentially forming images, and monochrome images are superimposed to obtain a multicolor image.

In all of these image forming devices, multiple image forming processes or a series of operations are incorporated until one complete image is obtained, and once the image forming operation starts partially, it operates continuously until the image is completed. It was like that.

In this way, conventional image forming apparatuses operate as a series from the start of the apparatus to the completion of the image, so for example, if an error in the document or operating condition settings of the apparatus is noticed immediately after the apparatus starts, it is possible to immediately stop the apparatus. Even if an attempt is made to do so, the device does not stop until all imaging processes are completed and continues to operate.

Therefore, during this time, unnecessary waiting time and wasteful consumption of toner transfer paper occur, which often results in a considerable drop in efficiency, especially when a large number of copies are to be made.

Therefore, in order to eliminate this waste of time and materials,
A color image forming apparatus has been proposed in which an emergency stop signal input at any time stops the image forming operation even if the image formation is not completed (Japanese Unexamined Patent Publication No. 62
-157068).

Problems to be Solved by the Invention In the color image forming apparatus described above, when an emergency stop signal is input, cleaning is performed by pressing the cleaning blade against the photoreceptor drum in a toner-free area slightly before the front edge of the formed toner image. It is supposed to be done.

However, when the cleaning blade is pressed against the toner-free area of the photoreceptor drum, the frictional force between the blade and the photoreceptor is too large, causing the tip of the blade to vibrate and collide irregularly with the photoreceptor drum. A so-called bounding phenomenon is likely to occur, which causes uneven cleaning and toner scattering, and adversely affects the durability of the cleaning blade.

SUMMARY OF THE INVENTION An object of the present invention is to provide a color image forming apparatus which can solve the above problems, can completely clean the surface of an image carrier when an emergency stop signal is input, and can improve the durability of a cleaning blade.

Means for Solving the Problems A color image forming apparatus according to the present invention includes an image bearing member, a latent image forming means for forming a latent image on the image bearing member, and a developing device including a plurality of developing units storing toners of different colors. means, a transfer means, a blade cleaning means for cleaning residual toner on the image carrier with a cleaning blade that can be pressed against and released from the image carrier, a transfer paper supply means, and a plurality of developing units of the developing means. In a color image forming apparatus equipped with a control means for controlling a color image forming process that is separately operated to form a color toner image, after at least a part of the color image forming process is started, an external operation is performed. In response to the generated emergency stop signal, the image forming operation is stopped even if the color image forming step is not completed, and a cleaning blade is pressed against the image carrier at the formed toner image portion to perform cleaning, The device is characterized in that the control means has a function of performing emergency stop control to bring the device into an initial state.

When performing emergency stop control, a cleaning blade may be brought into contact with the image carrier at a portion of the formed toner image, and then the image carrier may be rotated at least once to perform cleaning.

It may also include cleaning means or a counter-type cleaning blade.

The developing operation may be stopped in synchronization with the input of an emergency stop signal.

Operation During emergency stop control when an emergency stop signal is input, cleaning is performed by pressing the cleaning blade against the image carrier using the formed toner image area, so that when the cleaning blade presses against the image carrier, In addition, the toner in the toner image area acts as a lubricant, making it difficult for the bounding phenomenon to occur. It has been confirmed through experiments that when the cleaning blade presses the image carrier, if there is no toner in the area where the image carrier is pressed, the bounding phenomenon tends to occur, but if toner is present, the bounding phenomenon hardly occurs. It is being

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 schematically shows the mechanical structure of the main parts of a digital color copying machine, and FIG. 2 schematically shows the electrical structure of the main parts.

As shown in FIG. 1, the copying machine is equipped with an image carrier and a photosensitive drum (1) at 17, and a charger (2) is placed around it.
, a writing unit (3), a developing unit (4), a paper feeding unit (5), a transfer/separation unit (6), a fixing device (7), a static eliminator (8), a blade cleaning device (9), etc. ing. In addition, a document reading unit is installed below the document table (10) provided above these.
-(11) is provided. As shown in FIG. 2, the copying machine also includes an operation panel (12) for setting operating conditions, etc., and a control unit (12) for controlling the entire system.
18) etc.

The photosensitive drum (1) is driven by a main motor (14). Further, the entire circumferential surface of the photoreceptor drum (1) is charged by a charger (2), and as described later, images of a plurality of colors are superimposed on this.

The document reading unit (11) constitutes a document reading unit that scans and reads the document (15) placed on the document table (10) by exposure using a moving optical system.
16), a movable mirror unit (18), a lens (19), a photolysis prism (20) and an image sensor (CCD) (21).
) etc. Although not shown, the lamp unit (17) is provided with a cooling fan. Manuscript (1
5) is scanned by the lamp unit (17), and the image is reflected by the lamp unit (17) and the mirror of the movable mirror unit (18) and sent to the lens (19) and the photo-splitting prism (20), and the image is sent to the lens (19) and the photo-splitting prism (20). The light is split into two colors and images are formed on an image sensor (21) that receives each color image. The received color images are photoelectrically converted into electrical signals corresponding to each color image. After AD conversion is performed in the processing unit, the signal is further processed into an image signal for recording in the image processing unit (path shown).

The writing unit (3) is the reading unit (11)
The latent image forming means forms an electrostatic latent image by writing an image signal from an image processing section arranged in the photoreceptor drum (1) one by one for each recording color, and a semiconductor laser ( (path shown), a polygon motor (22), a polygon mirror (23), a fixed mirror (24), and the like.

The image sensor (
21) and a polygon mirror (23) that is rotated by a polygon motor (22) based on the image signals corresponding to the recording colors of red, blue, and black sent from the image processing section. ) and a fixed mirror (24) to form an electrostatic latent image on the uniformly charged peripheral surface of the photosensitive drum (1).

The developing unit (4) constitutes a developing unit that develops the latent image on the photoreceptor drum (1) into a toner image, and has a plurality of, for example, three developing units containing developers containing toners of different colors. It is equipped with containers (25), (26), and (27). The first developer (25) has red toner, the second developer (25) has red toner, and the second developer (25) has red toner.
2B) stores a developer containing blue toner, and the third developer (27) stores a developer containing black toner. These developing devices (25), (2B), and (27) are individually operated one by one to develop the electrostatic latent image on the photoreceptor drum (1) to form a toner image. In addition, one developing device (25)
(2B) While (27) is operating, other developing devices (
25) (2B) The developer layer in (27) is stationary apart from the photoreceptor drum (1) and is in an inactive state. In addition, these developing devices (25) (2B) (27
>, a two-component non-contact development method is preferably used.

The paper feed unit (5) constitutes a transfer paper supply unit that supplies transfer paper to the photoreceptor drum (1), and includes a paper feed cassette (28), a paper feed roller (29), and the like.

The transfer/separation unit (B) constitutes a transfer means for transferring the toner image formed on the photoreceptor drum (1) to transfer paper, and includes a transfer device (30), a separator (31), etc. We are prepared.

The cleaning device (9) constitutes a blade cleaning means that cleans the peripheral surface of the photoreceptor drum (1) with a cleaning blade (32). blade(
32) rotates slightly around the support part (32a) on the proximal end side, and the groove part (32b) on the distal end side is attached to the photoreceptor drum (1).
) and a press release state in which the edge portion (32b) separates from the surface of the photoreceptor drum (1). Preferably, the blade (32) is of a counter type, and the support portion (32a) is located downstream of the edge portion (32b) relative to the rotation of the photoreceptor drum (1). If the blade (32) is made of a counter type, compared to the Trail 2 type in which the support part is located upstream of the edge part with respect to the rotation of the photoconductor drum, the blade (32) will not be able to hold the photoconductor even if the pressing load of the blade is the same. The drum (1) has a large frictional torque in the rotational direction, and a small and thin drum can be used.

Although not shown, the operation panel (12) is provided with a start key, an emergency stop key, various operating condition setting keys, various indicators, and the like.

The control unit (13) constitutes a control means for controlling each part of the copying machine to control the color image forming process, and includes a microcomputer (path shown). The photosensitive drum (1), charger (2), reading unit (11), writing unit (3), developing unit (4), paper feeding unit (5), transfer/separation unit (6), The fixing device (7), the static eliminator (8), the cleaning device (9), etc. are sequentially controlled by a program stored in the memory of the microcomputer of the control unit (13).

In the case of color copying, charging of the photosensitive drum (1) by the charger (2), exposure scanning of the original (15) by the reading unit (11), formation and development of a latent image by image exposure of the writing unit (3). Vessel (25) (26) (
The imaging process including development according to 27) is repeated three times,
As a result, a multicolor toner image, which is a composite of monochrome toner images, is formed on the photoreceptor drum (1).

In the first image creation process, the reading unit (
In step 1), the document is exposed for recording with red toner, for example, and an image signal corresponding to the red toner recording is output from the image processing section to the writing unit (3). The photoreceptor drum (1) is charged by a charger (2), and based on the image signal for recording red toner, red toner is applied onto the photoreceptor drum (1) by image exposure of the writing unit (3). An electrostatic latent image is formed for recording. This electrostatic latent image for red toner recording is developed by the operation of the first developing device (25) having red toner, thereby forming a red toner image.

Similarly, in the second image forming process, the reading unit (II) exposes the document for recording with, for example, blue toner, and an image signal corresponding to blue toner recording is sent from the image processing section to the writing unit (3). ), and based on this image signal for blue toner recording, an electrostatic latent image for blue toner recording is formed on the photoreceptor drum (1) by image exposure of the writing unit (3). This electrostatic latent image for blue toner recording is developed by the operation of a second developer (26) having blue toner;
A blue toner image is further formed on the photoreceptor drum (1) having the red toner image.

Furthermore, similarly, in the third image forming process, the document is exposed for recording with black toner, for example, and an image signal corresponding to black toner recording is output from the image processing section to the writing unit (3). Based on this image signal for black toner recording, the writing unit (
By the image exposure in step 3), an electrostatic latent image for black toner recording is formed on the photoreceptor drum (1). This electrostatic latent image for black toner recording is produced by a third developing device (
27), and a black toner image is further superimposed on the photosensitive drum (1) having the red and blue toner images. As a result, a multicolor toner image of red, blue, and black is formed on the photoreceptor drum (1).

When a multicolor toner image is formed through three image forming processes in this way, the transfer paper is supplied from the paper feed cassette (28) to the photosensitive drum (1), and the transfer/separation unit (
6) is activated, and the toner image is transferred to the transfer paper. Then, the transfer paper onto which the toner image has been transferred is fixed by a fixing device (7), and a completed copy is ejected onto a paper ejection tray (shown @).

During the three image forming processes described above, the cleaning blade (32) is separated from the photoreceptor drum (1) and stops operating. When the transfer is finished, remove the cleaning blade (32
) is pressed against the photoreceptor drum (1), and the photoreceptor drum (1) is pressed against the photoreceptor drum (1).
) is removed and the entire photoconductor drum ( ) has been cleaned, the cleaning blade (3) is removed.
2) separates from the photoreceptor drum (1) and stops operating, and the photoreceptor drum (1) also stops, completing one image forming cycle.

FIG. 3 is a time chart showing the progress of the image forming process in the above-mentioned copying machine.

In Figure 3, the solid lines indicate processes during normal operation, and the periods in the upper row of each line indicate that the process is in operation, and the periods in the lower row indicate that the process is in a dormant state. .

When a start signal is input at time to, the photoreceptor drum (1
) starts rotating, and at the same time, the charger (2) operates to charge the entire surface of the photoreceptor drum (1). Photosensitive drum (1
) rotates and when the vicinity of the beginning of the charged part reaches the position of the writing unit (3), the reading unit (11
) is activated to start exposing the document for red toner recording, and at the same time, image exposure of the writing unit (3) is activated to start forming a latent image for red toner recording (time tl). When the vicinity of the beginning of the red latent image on the photosensitive drum (1) reaches the position of the first developing device (25), the first developing device (
25) is activated and development with red toner is started (time t2), which varies depending on the recording length, but in the case of maximum flame recording, this continues while the photoreceptor drum (1) rotates approximately once.

When the photoreceptor drum (1) rotates and the vicinity of the beginning of the red torch image reaches the position of the charger (2) again, the photoreceptor drum (
1) is charged again, and document exposure and image exposure for blue toner recording are started (time t3). Furthermore, the vicinity of the beginning of the blue latent image on the photoreceptor drum (1) is located in the second developing device (2).
When the position 6) is reached, the second developing device (26) is activated.
Development using blue toner is started (time t4). At this time, the blue toner image is formed overlapping the already formed red toner image.

Similarly, document exposure and image exposure for black toner recording are started from time t5, and development with black toner is started from time t6, but when the vicinity of the beginning reaches the transfer/separation unit (6), (time t7), transcription/
The separation unit (6) is activated, and the toner image on the photoreceptor drum (1) is started to be transferred to the transferred transfer paper in synchronization with the toner image on the photoreceptor drum (1), and the photoreceptor drum (1) rotates approximately once to complete the entire image. This continues until transfer and separation are complete.

When the leading edge of the photosensitive drum (1) that has been transferred and separated reaches the position of the static eliminator (8) (time t8), the static eliminator (
8) further reaches the position of the cleaning device (9) (time t9), the cleaning device (9) is activated and starts cleaning the surface of the photoreceptor drum (1).

When the photoreceptor drum (1) rotates approximately one more rotation to finish cleaning the entire surface and returns to the position shown in FIG. 1, the photoreceptor drum (1) stops. Then, one cycle of multicolor image formation is completed (time t10).

During this period, charging is at time tll, original exposure and image exposure are at 3
Time t12, that is, the end of the black image forming process
, development at time t13, transfer at time t14, static elimination at time t
15. The cleaning operation is sequentially stopped at time t1B,
At the time tlO when the photosensitive drum (1) stops, everything returns to its initial state and is ready for the next start. The interval between the above points corresponds to the distance on the photoreceptor drum (1) of each device. Note that in FIG. 3, arrows 1 to 4 indicate the point in time when the photoreceptor drum (1) rotates once after startup and returns to the startup position, and from this point on, one cycle is completed with four rotations of the photoreceptor drum. I understand that.

Next, the operation of the above-mentioned copying machine during an emergency stop will be explained.

For example, if an emergency stop signal is input from the emergency stop key at time Tl when original exposure for red toner recording, image exposure for red toner recording, and red toner development are in progress after startup at time t1, the control Unit (13)
performs the emergency stop operation shown in dotted lines in FIG. 3 according to a predetermined program. That is, at the same time as the stop signal is input, charging, document exposure by scanning the exposure lamp (16), image exposure, and development operations are stopped, and the front end of the developed red toner image reaches the position facing the static eliminator (8). At time T2, the static eliminator (8) starts operating. Subsequently, at time T3 when the front end of the developed red toner image passes through the cleaning device (9), the blade (32) presses the red toner image onto the photoreceptor drum (1) and removes the toner that has already adhered. Start removal. The static eliminator (8) and the cleaning device (9) continue to open for at least one rotation of the photoreceptor drum (1), and at time T4, the static eliminator (8) stops operating, and at time T5, the blade (32) moves away from the photoreceptor drum (1) and stops operating. Then, when the cleaning is completed, the photosensitive drum (1) stops and becomes ready to be restarted (time T6).

During the above-mentioned emergency stop control, the cleaning blade (32) presses against the photoreceptor drum (1) at the part of the formed toner image, so the blade (32) presses against the photoreceptor drum (1).
When press-bonding the toner image, the toner in the toner image area becomes sticky or acts as a lubricant, making it difficult for the bounding phenomenon to occur. Therefore, the surface of the photoreceptor drum (1) is completely cleaned, a good color image can be obtained next time, and the durability of the blade (32) is also improved.

During emergency stop control, when pressing the cleaning blade (32) onto the photoreceptor drum (1), the blade (
The speed of step 32) may be switched in two stages. This will further increase the effect of preventing the bounding phenomenon.

Furthermore, when an emergency stop signal is input, after stopping the image forming process, the cleaning blade (32) is moved to the photoreceptor drum (1).
), the rotational speed of the photoreceptor drum (1) may be lowered, for example, to about 1/2 to 115. In this way, the photoreceptor drum (1
) by crimping the blade (32) on the blade (32), the effect of preventing the bounding phenomenon will be even greater, and the cleaning action will be more complete.
The durability is also improved several times.

Note that if the emergency stop signal is input before the first color development starts, there is no need for cleaning, so it is sufficient to activate only the static eliminator (8) to stop the development. in this case,
If unnecessary, the photoreceptor drum (1) may be stopped after less than one revolution.

In the above-mentioned copier, it is possible to input an emergency stop signal at any point in the process of forming a multicolor image to immediately stop the device, thereby reducing wasteful consumption of materials such as toner and transfer paper, and work time. can be significantly reduced.

The present invention can also be applied to color image forming apparatuses other than digital color copying machines as described above.

For example, the present invention can be similarly applied to a transfer drum type analog color copying machine as shown in Japanese Patent Application Laid-Open No. 2-13977.

Effects of the Invention According to the color image forming apparatus of the present invention, as described above, it is possible to prevent the occurrence of the bounding phenomenon when the cleaning blade presses against the image carrier during emergency stop control, and therefore, It is possible to completely clean the surface of the image carrier to obtain a good color image, and to improve the durability of the blade (32).

[Brief explanation of the drawing]

FIG. 1 is a schematic longitudinal sectional view of the main parts of a digital color copying machine showing an embodiment of the present invention, FIG. 2 is a block diagram of the main parts of the copying machine, and FIG. 3 shows the normal operation and It is a time chart showing an example of the operation of each part during an emergency stop. (1)...Photosensitive drum (image carrier), (3)...
・Writing unit (latent image forming means), (4)...
Developing unit (developing means), (5)...Paper feeding unit (transfer paper supplying means), (6)...Transfer/separation unit (transfer means), (9)...Blade cleaning device (cleaning means) ), (13)...control unit (control means), (25) (2B) (27)...
・Developer, (32)...Cleaning blade. that's all

Claims (4)

[Claims] (1) An image bearing member, a latent image forming means for forming a latent image on the image bearing member, a developing means having a plurality of developing devices containing toner of different colors, a transfer means, and a pressure-bonding method for the image bearing member.
A color image forming a color toner image by separately operating a blade cleaning means for cleaning residual toner on an image carrier with a cleaning blade that can be released from pressure, a transfer paper supply means, and a plurality of developing devices of the developing means. In a color image forming apparatus equipped with a control means for controlling a forming process, after at least a part of the color image forming process is started, the color image forming process is stopped by an emergency stop signal generated by an external operation. It also has an emergency stop control function that stops the image forming operation even if the image forming operation is not completed, and also performs cleaning by pressing the cleaning blade against the image carrier in the area where the toner image has been formed, returning the device to its initial state. A color image forming apparatus characterized in that the control means has. (2) When performing the emergency stop control, cleaning is performed by pressing the cleaning blade against the image carrier at a portion of the formed toner image and then rotating the image carrier at least once. (1) Color image forming apparatus. (3) The color image forming apparatus according to claim 1, wherein the cleaning means includes a counter type cleaning blade. (4) The color image forming apparatus according to claim (1), wherein the developing operation is stopped in synchronization with the input of an emergency stop signal.