JP3651492B2 - Image forming apparatus - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an electrophotographic image forming apparatus such as a printer, a facsimile machine, and a copying machine, and more particularly to an image forming apparatus capable of forming a color image.
[0002]
[Prior art]
As disclosed in U.S. Pat. No. 4,897,677, a conventional color image forming apparatus is greatly reduced in size by arranging four electrophotographic process sections in parallel along the photosensitive drum. Yes.
[0003]
However, in the color image forming apparatus as disclosed in the above-mentioned US patent specification, it is difficult to increase the image forming speed because the print head is moved serially.
[0004]
[Problems to be solved by the invention]
The present invention has been made in view of such conventional problems, and an object of the present invention is to provide an image forming apparatus capable of high-speed image formation and suitable for downsizing a photosensitive member and an intermediate transfer member. It is in. Another object of the present invention is to provide an image forming apparatus capable of forming a color image with a minimum image memory capacity. Another object of the present invention is to provide an inexpensive image forming apparatus with a reduced image memory capacity.
[0005]
[Means for Solving the Problems]
  The image forming apparatus of the present invention includes an image carrier, a charging unit for charging the image carrier, an exposure unit for forming an electrostatic latent image on the image carrier according to image formation information, and the image carrier. Electrostatic latent imageMulti-coloredDeveloping means for developing a toner image, transfer means for transferring the developed toner image to a transfer material, fixing means for fixing the toner image on the transfer material, and image forming information are stored.Band memoryAnd control means for controlling the image forming operation, and can form an image by dividing the band into a predetermined length with respect to the moving direction of the image carrier.ColorIn the image forming apparatus, the length of the band is ½ or less of the maximum image size,The control means includes means for determining whether or not image formation information for a band length is stored in the band memory, and means for confirming whether or not to form an image of the next color.The image formation information isBand memoryThe image forming operation is started or continued, and the image forming information isBand memoryIf it is not stored, the image forming operation is stopped or interrupted,Continue image forming operation when next color image forming information is in the band memoryIt is characterized by doing.
[0006]
  The image forming apparatus according to the present invention includes:The control means is further provided with means for confirming whether or not to form an image of the next band.It is characterized by that.
[0007]
Furthermore, the image forming apparatus of the present invention is characterized in that the image forming operation is stopped or interrupted in the non-image area of the image carrier by the control means.
[0011]
[Action]
  According to the above configuration of the present invention, it is possible to form an image by dividing the band into a predetermined length with respect to the moving direction of the image carrier.ColorIn the image forming apparatus, the length of the band is set to 1/2 or less of the maximum image size, and the image forming information of the band isBand memoryThe image forming operation is started or continued when it is stored in theBand memoryIf it is not stored, the image forming operation is stopped or interrupted.When the next color image formation information is in the band memory, the image formation operation is continued.As a result, the image forming operation can be interrupted only when the amount of image forming information is enormous, and not only high-speed image formation can be performed with the storage capacity for the band length, but also the length for the band length ( A small-sized image carrier or intermediate transfer member having a (peripheral length) can be used. Regarding the storage capacity, in order to form a binary full-color image at an A3 image size of 600 dpi, 8 MB is required for one color, so that a storage capacity of 32 MB is required for four colors. If so, the maximum storage capacity is 4 MB.Therefore, a color image can be formed by a small image forming apparatus having only a small memory capacity.
[0012]
  Also,By forming an image by dividing it into bands, code data such as characters can be continuously printed at high speed, and in the case of complicated and enormous graphic data, an image is gradually formed according to the data transfer. The amount of memory of the image forming apparatus can be reduced.be able to.
[0013]
Further, by stopping or interrupting the image forming operation in the non-image area of the image carrier by the control means, it is possible to prevent toner adhesion to the image carrier due to dark decay of the image carrier when the image forming operation is restarted. it can.
[0017]
【Example】
Hereinafter, the present invention will be described in detail with reference to the drawings.
[0018]
FIG. 1 is a cross-sectional view of an essential part showing an embodiment of an image forming apparatus of the present invention.
[0019]
In the present invention, since the image forming apparatus is configured using the electrophotographic system, first, the image forming process of the present embodiment will be described in the order of the process with reference to FIG.
[0020]
In the figure, reference numeral 10 denotes an image carrier formed in a drum shape, and this image carrier 10 is an organic photoreceptor in which a charge generation layer and a charge transport layer are formed in this order on an anodized aluminum drum. The image carrier 10 rotates in the direction of arrow A along with the image forming operation, and is charged, exposed and developed.
[0021]
In the figure, reference numeral 21 denotes a corona charger (scorotron charger) which is a charging means, a bias of about DC (−) 5 kV is applied to the charging wire of the corona charger 21, and DC (−) 700 V is applied to the charging grid. When a bias voltage of about a level is applied, the surface of the image carrier 10 can be uniformly charged to a charging potential of about (−) 700 V sequentially.
[0022]
Next, the charged image carrier 10 is subjected to image exposure by the exposure means 30, and the potential of the image exposure portion becomes (−) 50V to (−) 150V. The exposure unit 30 includes a semiconductor laser 31, a polygon motor 32, an imaging lens 33, a mirror 35, and the like. A beam 34 emitted from the semiconductor laser 31 is polarized and scanned by the polygon motor 32 and corrected by the imaging lens 33. Then, the light is reflected by the mirror 35 and applied to the image carrier 10. In this way, an electrostatic latent image is formed on the image carrier 10.
[0023]
Subsequently, in the image carrier 10 on which the electrostatic latent image is formed, the toner is developed on the image portion by the developing unit, and the electrostatic latent image is visualized. The developing means includes a yellow developing device 41 having a yellow developing roller 45 for developing yellow toner, a magenta developing device 42 having a magenta developing roller 46 for developing magenta toner, and a cyan developing roller 47 for developing cyan toner. A cyan developing device 43 and a black developing device 44 having a black developing roller 48 for developing black toner. The electrostatic latent image of the image carrier 10 is activated by operating each developing device according to image color data. Develop one by one. Each of the developing rollers 45 to 48 is disposed at a non-contact position with respect to the image carrier 10 and performs color switching by applying a developing bias voltage and rotating the developing roller.
[0024]
Subsequently, in the case of forming a color image with a plurality of color toners, the charging, exposing, and developing steps are repeated according to the number of colors, and a plurality of color toners are superimposed on the image carrier 10 to form a color image. A toner image is formed.
[0025]
When development is completed and a desired toner image is formed on the image carrier 10, the toner image is transferred to the recording material 57 conveyed along with the leading edge of the image by the corona transfer device 51 as a transfer unit. The At the time of transfer, the residual charge on the image carrier 10 is removed by the charge eliminating lamp 60 to prevent the transfer residue of the image edge portion. Note that the corona transfer device 51 is configured to be movable integrally with a paper conveyance belt 52 described later, and swings in the direction of arrow C only when the toner image is transferred to the recording material 57 so that the recording material 57 is supported on the image. The toner image on the body 10 is closely attached.
[0026]
The transfer residual toner remaining on the image carrier 10 after being transferred is scraped off by the cleaning blade 71 and discharged into the internal space of the cleaning device 70. The cleaning device 70 moves and cleans the image carrier 10 in the direction of the arrow B corresponding to the portion where the toner image is transferred to the recording material 57, but otherwise cleans the image carrier 10. It is held at a separated position.
[0027]
By the way, the recording material 57 is fed along the paper path 59 in accordance with the transfer of the toner image. From the paper feed tray 56 that stores the recording material 57 such as a large number of sheets of paper, a half-moon shaped paper feeding roller is provided. It is taken out by 58 and sent to the paper conveying belt 52. The recording material 57 is electrostatically adsorbed on the paper conveying belt 52, and the recording material 57 is conveyed to the transfer unit, and a toner image is formed on the recording material 57. Further, the recording material 57 is conveyed to the fixing unit 80, and after the toner image is heated and fixed, it is discharged to a discharge tray (not shown). The paper transport belt 52 is rotationally driven in the direction of arrow D by the drive roller 53 and is stretched between the drive roller 53, the driven roller 54, and the idler 55, and is disposed inside the paper transport belt 52. The above-mentioned corona transfer device 51 is supported integrally with the rotation center of the drive roller 53 so as to be swingable in the direction of arrow C, and moves the recording material 57 in the direction of the image carrier 10 only at the time of transfer. It is. The fixing device 80 includes a heating roller 81 and a pressure roller 82. The fixing device 80 rotates in the direction of arrow E and arrow F, respectively, and a heater 83 disposed inside the pressure roller 81 is used as a heat source. The toner image on the recording material 57 is heated and fixed.
[0028]
In this embodiment, a color image is formed by the electrophotographic process as described above. Hereinafter, control means for controlling the image forming operation will be described with reference to FIG.
[0029]
In the figure, reference numeral 90 is a control means for controlling the image forming operation, and the control means 90 performs at least lighting control of the semiconductor laser 31, rotation driving control of the polygon motor 93, and heating control of the fixing device 80. is there.
[0030]
First, regarding the lighting control of the semiconductor laser 31, desired image formation information is stored in a band memory 91 that stores image formation information for a band of a predetermined length and a size equal to or less than ½ of the maximum image size. The control unit 90 detects whether or not the information has been stored. When the image forming information of the band is stored in the band memory 91, the control unit 90 sends data to the laser driver 92 to start or continue the image forming operation. When the band image formation information is not stored in the band memory 91, the image forming operation is stopped or interrupted to enter a standby state.
[0031]
In this way, since the image is formed by dividing into bands, the circumference of the image carrier 10 may be slightly longer than the length of the band, and the diameter of the image carrier 10 can be reduced. .
[0032]
Here, by setting the storage capacity of the band memory 91 to ½ or less of the storage capacity capable of storing the image formation information of the maximum image size, the minimum storage capacity can be achieved depending on the application. For example, a device that forms an A3 size image has only a storage capacity corresponding to an A4 size image, and the storage capacity is reduced by dividing the A3 size image into two parts, or further divided into a plurality of bands. Storage capacity can be reduced.
[0033]
Note that the control unit 90 stops or interrupts the image forming operation by rotating the image carrier 10 by a constant rotation even after the image forming operation of the band having a predetermined length on the image carrier 10 is completed. It is possible to prevent fluctuations in potential due to dark decay of the carrier 10 and reduce image defects such as fluctuations in image density.
[0034]
Next, regarding the rotational drive control of the polygon motor 93, the motor driver 93 that rotationally controls the polygon motor 32, which is a rotary scanning device, is kept rotated at a constant speed by the control means 90 even during the interruption period of the image forming operation. It controls to do. In general, in a high-speed image forming apparatus, in particular, a color image forming apparatus, the polygon motor 32 rotates around 20,000 rpm, so that it takes about 10 seconds each to start and stop.
[0035]
In this way, by rotating the polygon motor 32 at a constant speed even during the interruption period of the image forming operation, the waiting time associated with the start and stop is omitted, and even when the image is formed by dividing into bands, the high speed is achieved. An image can be formed.
[0036]
Finally, with respect to the heating control of the fixing device 80, the heater driver 94 that controls the heating of the heater 83 is controlled by the control unit 90 at a temperature equal to or lower than the fixing temperature during the interruption period of the image forming operation and the start of image formation. In response to the above, the temperature is controlled to a temperature at which the temperature can be raised to the fixing temperature in a certain time, and control is performed so as to maintain the preheating state.
[0037]
As described above, even when the image forming operation is interrupted, the fixing device 80 is heated to the preheated state, so that the waiting time associated with the heating temperature rise is omitted and the image is divided into bands. An image can be formed at high speed.
[0038]
1 has been described so far, a flowchart for forming an image by dividing the image into bands will be described with reference to FIG.
[0039]
FIG. 2 is a flowchart in another embodiment of the present invention.
[0040]
In FIG. 2, upon receiving a print start signal, the image forming apparatus performs initialization adjustment such as cleaning of the image carrier and detection of paper jam. When the initialization adjustment is completed, the process shifts to a standby state where image formation is possible. Subsequently, when the image forming information for the band length is stored in the band memory, the image forming operation as described above is performed. As soon as the image forming operation for one band is completed, it is confirmed whether or not an image of the next color is to be formed. When forming an image of the next color, check whether there is band information for forming the next image. If there is band information, image formation is continued. The image forming operation is interrupted in the standby state. When an image of the next color is not formed, it is confirmed whether or not an image of the next band is formed. When forming an image of the next band, check whether there is band information for forming the next image. If there is band information, image formation is continued. If there is no band information, The image forming operation is interrupted in the standby state. By repeating these operations, a color image for one page is formed, and when it continues to the next page, the same operation is repeated to complete the formation of the color image. In the procedure of this embodiment, color superposition can be performed for each band. However, after images are formed in order of bands for each color, color superposition can also be performed collectively.
[0041]
In this way, by dividing the image into bands according to the above procedure and forming an image, continuous printing is possible at high speed in the case of code data such as characters, and data in the case of complicated and enormous graphic data. Accordingly, an image can be gradually formed according to the transfer of the image data, and the memory capacity of the image forming apparatus can be reduced.
[0042]
Incidentally, since the configuration of the present invention can be applied to an image forming apparatus using an intermediate transfer member, an example using the intermediate transfer member will be described below with reference to FIG.
[0043]
FIG. 3 is a cross-sectional view of an essential part showing another embodiment of the image forming apparatus of the present invention.
[0044]
Also in this embodiment, since the image forming apparatus is configured using the electrophotographic system, the image forming process will be described in the order of processes. In addition, in order to avoid duplication description with FIG. 1, about the member which has the same function, the same number is attached | subjected and description is abbreviate | omitted.
[0045]
In FIG. 3, an image carrier 11 composed of an organic photoreceptor rotates in the direction of arrow H along with the image forming operation, and is charged, exposed and developed.
[0046]
The charging roller 22 is driven to rotate in the direction of arrow I with respect to the image carrier 11 and can sequentially uniformly charge the surface of the image carrier 11 to a constant charging potential.
[0047]
Next, the charged image carrier 11 is image-exposed by the exposure unit 30, and an electrostatic latent image is formed on the image carrier 11.
[0048]
Subsequently, in the image carrier 11 on which the electrostatic latent image is formed, the toner is developed on the image portion by the developing means 140 that supports the developing devices of the respective colors in a rotating manner and can rotate in the direction of the arrow J. The image is visualized. The developing means includes a yellow developing unit 141 having a yellow developing roller 145 for developing yellow toner, a magenta developing unit 142 having a magenta developing roller 146 for developing magenta toner, and a cyan developing roller 147 for developing cyan toner. A cyan developing device 143 and a black developing device 144 having a black developing roller 148 for developing black toner. The electrostatic latent image of the image carrier 11 is operated by operating each developing device according to image color data. Develop one by one. Each of the developing rollers 45 to 48 is disposed at a position where it can come into contact with the image carrier 10, but the color is switched by the rotation of the developing unit 140 and at the position between the developing rollers 140. There is a sufficient gap between the image carrier 11 and no contact with the image carrier 11.
[0049]
The developed toner is primary-transferred by applying a bias to the intermediate transfer member 160 that rotates in the direction of the arrow K. In the case of forming a color image with a plurality of colors of toner, charging, exposure, and development steps are performed. Is repeated according to the number of colors, and sequentially transferred one by one onto the intermediate transfer body 160, and a plurality of color toners are superimposed to form a color toner image. At the time of transfer, the residual charge on the image carrier 11 is removed by the charge eliminating lamp 60 to prevent the transfer residue of the image edge portion. Further, the intermediate transfer body 160 is configured to be movable in the direction of arrow L, and moves only in the direction of the image carrier 11 when the toner image is primarily transferred to the recording material 57, so that the intermediate transfer body 160 is moved to the image carrier 11. Adhere to the upper toner image. Further, the circumferential length of the intermediate transfer member 160 is preferably an integral multiple of the circumferential length of the image carrier 11 or a fraction of an integer in order to improve the transfer position accuracy.
[0050]
A toner image having a predetermined band length formed on the intermediate transfer body 160 is transferred to the recording material 57 that is conveyed in accordance with the leading edge of the image by a transfer brush 151 serving as a transfer unit. Transcribed. In the secondary transfer, by applying a bias to the transfer brush 151, a transfer electric field is formed between the paper transfer belt 152 having at least a predetermined resistance in the thickness direction and the intermediate transfer body 160, and a toner image is formed. Secondary transfer is performed on the recording material 57. Further, the transfer brush 151 is configured to be movable integrally with a paper conveyance belt 152 described later, and swings in the direction of the arrow P only when the toner image is secondarily transferred to the recording material 57 to transfer the recording material 57 to the intermediate transfer. The toner image on the body 160 is brought into close contact with the toner image.
[0051]
On the other hand, the transfer residual toner remaining after the primary transfer on the image carrier 11 is scraped off by the cleaning blade 71 and discharged into the internal space of the cleaning device 70.
[0052]
On the other hand, the transfer residual toner remaining after the secondary transfer on the intermediate transfer body 160 is scraped off by the second cleaning blade 171 and discharged into the internal space of the second cleaning device 170. The second cleaning device 170 moves and cleans the intermediate transfer member 160 in the direction of the arrow M corresponding to the portion where the toner image is transferred to the recording material 57, but otherwise the image is transferred to the image carrier 10. It is held at a position spaced from the other.
[0053]
By the way, the recording material 57 is fed in accordance with the transfer of the toner image, but the paper conveying belt 152 electrostatically attracts the recording material 57 on the recording material 57 and conveys the recording material 57 to the transfer unit, thereby the toner image. Is formed on the recording material 57. Further, the recording material 57 is conveyed to the fixing unit 80, and after the toner image is heated and fixed, it is discharged to a discharge tray (not shown). The paper transport belt 152 is rotationally driven in the direction of arrow N by the drive roller 153 and is stretched between the drive roller 153 and the driven roller 154. The paper transport belt 152 is disposed inside the paper transport belt 152. The transfer material 151 is supported so as to be swingable in the direction of arrow P around the rotation center of the drive roller 153, and the recording material 57 is moved in the direction of the intermediate transfer body 160 only at the time of secondary transfer. . The fixing device 80 includes a heating roller 81 and a pressure roller 82, and rotates in the direction of the arrow Q and the direction of the arrow R, respectively.
[0054]
In this embodiment, a color image is formed by the electrophotographic process as described above. Hereinafter, control means for controlling the image forming operation will be described with reference to FIG.
[0055]
In the figure, reference numeral 190 denotes a control means for controlling the image forming operation. The control means 190 at least controls the lighting of the semiconductor laser 31, the rotational drive control of the polygon motor 93, the color switching control of the developing means 140, and the fixing. Heating control of the device 80 is performed.
[0056]
First, regarding the lighting control of the semiconductor laser 31, the band memory 91 stores image formation information for a band having a size equal to or less than ½ of the maximum image size and a length equal to or less than the circumferential length of the intermediate transfer body 160. The control unit 190 detects whether or not the desired image formation information is stored. When the band image formation information is stored in the band memory 91, the control unit 190 sends data to the laser driver 92 to form an image. The operation is started or continued, and when the band image formation information is not stored in the band memory 91, the image formation operation is stopped or interrupted to enter a standby state.
[0057]
As described above, since the image is formed by being divided into bands, the circumference of the image carrier 11 can be shortened, and the circumference of the intermediate transfer member 160 can be slightly longer than the length of the band. The intermediate transfer member 160 can be reduced in diameter.
[0058]
Here, by setting the storage capacity of the band memory 91 to ½ or less of the storage capacity capable of storing the image formation information of the maximum image size, the minimum storage capacity can be achieved depending on the application. For example, a device that forms an A3 size image has only a storage capacity corresponding to an A4 size image, and the storage capacity is reduced by dividing the A3 size image into two parts, or further divided into a plurality of bands. Storage capacity can be reduced.
[0059]
Note that the control unit 190 stops or interrupts the image forming operation by rotating the image carrier 11 at a constant rotation even after the image forming operation of the band having a predetermined length on the image carrier 11 is completed. It is possible to prevent fluctuations in potential due to dark decay of the carrier 11 and reduce image defects such as fluctuations in image density.
[0060]
Next, regarding the rotational drive control of the polygon motor 93, the motor driver 93 that rotationally controls the polygon motor 32, which is a rotary scanning device, is kept rotated at a constant speed by the control means 90 even during the interruption period of the image forming operation. It controls to do. In general, in a high-speed image forming apparatus, in particular, a color image forming apparatus, the polygon motor 32 rotates around 20,000 rpm, so that it takes about 10 seconds each to start and stop.
[0061]
In this way, by rotating the polygon motor 32 at a constant speed even during the interruption period of the image forming operation, the waiting time associated with the start and stop is omitted, and even when the image is formed by dividing into bands, the high speed is achieved. An image can be formed.
[0062]
Next, regarding the color switching control of the developing unit 140, the developing motor driver 195 is controlled by the control unit 190 to rotate the rotating type developing unit 140 according to the color of the toner to be developed and to form an image. During the operation interruption period, the rotation position of the developing means 140 is stopped so that the portion facing the image carrier 11 is at an intermediate position between the development rollers so that the developing roller does not contact the image carrier 11. .
[0063]
As described above, during the interruption period of the image forming operation, each developing roller is kept in a position not facing the image carrier 11 to prevent toner adhesion to the image carrier and toner scattering in the apparatus. Can do.
[0064]
Finally, with respect to the heating control of the fixing device 80, the heater driver 94 that controls the heating of the heater 83 is controlled by the control unit 90 at a temperature equal to or lower than the fixing temperature during the interruption period of the image forming operation and the start of image formation. In response to the above, the temperature is controlled to a temperature at which the temperature can be raised to the fixing temperature in a certain time, and control is performed so as to maintain the preheating state.
[0065]
As described above, even when the image forming operation is interrupted, the fixing device 80 is heated to the preheated state, so that the waiting time associated with the heating temperature rise is omitted and the image is divided into bands. An image can be formed at high speed.
[0066]
Therefore, according to these embodiments, a color image can be formed by a small image forming apparatus having a memory with a small storage capacity.
[0067]
【The invention's effect】
  As described above, according to the present invention, an image can be formed by being divided into bands having a predetermined length with respect to the moving direction of the image carrier.ColorIn the image forming apparatus, the length of the band is set to 1/2 or less of the maximum image size, and the image forming information of the band isBand memoryThe image forming operation is started or continued when it is stored in theBand memoryIf it is not stored, the image forming operation is stopped or interrupted.The image forming operation is continued when the next color image forming information is in the band memory.As a result, the image forming operation can be interrupted only when the amount of image forming information is enormous, and not only high-speed image formation can be performed with a storage capacity corresponding to the band length, but also the length corresponding to the band length ( A small-size image carrier or intermediate transfer memberHave only a small memory capacitySmallColorAn image forming apparatus can be provided.
[0068]
  Also,By forming an image by dividing it into bands, code data such as characters can be continuously printed at high speed, and in the case of complicated and enormous graphic data, an image is gradually formed according to the data transfer. The amount of memory of the image forming apparatus can be reduced.be able to.
[0069]
Further, by stopping or interrupting the image forming operation in the non-image area of the image carrier by the control means, it is possible to prevent toner adhesion to the image carrier due to dark decay of the image carrier when the image forming operation is restarted. And a highly reliable image forming apparatus can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part of an image forming apparatus showing an embodiment of the present invention.
FIG. 2 is a flowchart of an image forming apparatus according to another embodiment of the present invention.
FIG. 3 is a cross-sectional view of a main part of an image forming apparatus showing still another embodiment of the present invention.
[Explanation of symbols]
10, 11 Image carrier
21 Corona charger
22 Charging roller
30 Exposure means
31 Semiconductor laser
32 Polygon motor
140 Developing means
41 Yellow developer
42 Magenta Developer
43 Cyan developer
44 Black developer
51 Corona transfer device
151 Transfer brush
52,152 Paper transport belt
57 Recording material
60 Static elimination lamp
70 Cleaning device
90, 190 Control means
91 band memory
92 Laser driver
93 Motor driver
94 Heater driver
195 Development motor driver
170 Second cleaning device
160 Intermediate transfer member

Claims (3)

An image bearing member, a charging unit that charges the image bearing member, an exposure means for forming an electrostatic latent image on the image bearing member in accordance with image formation information, a plurality of colors to the electrostatic latent image on said image bearing member A developing unit that visualizes the toner image, a transfer unit that transfers the developed toner image to a transfer material, a fixing unit that fixes the toner image on the transfer material, a band memory that stores image formation information, A color image forming apparatus capable of forming an image by dividing the band into a predetermined length with respect to the moving direction of the image carrier. The control means forms a next color image with means for determining whether or not image forming information for the band length is stored in the band memory. the means to check whether the installed, Serial image forming operation start or continue if the image forming information is stored in the band memory, stop or suspend the image forming operation when the image formation information is not stored in the band memory, the following A color image forming apparatus which continues an image forming operation when color image forming information is in the band memory . 2. An image forming apparatus according to claim 1 , wherein said control means further comprises means for confirming whether or not an image of the next band is to be formed. The image forming apparatus according to claim 2, wherein the control unit stops or interrupts an image forming operation in a non-image area of the image carrier.

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