JP3588413B2 - Image forming device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrophotographic image forming apparatus.
[0002]
[Prior art]
In a digital color copying machine, exposure scanning of a document is performed by moving a carriage having a predetermined optical system under a document by a predetermined driving source. Prior to the execution of the exposure scanning, the carriage is moved according to the magnification of the copy, and the position is set as the home position.
[0003]
[Problems to be solved by the invention]
However, when forming a color image by scanning a single original continuously a plurality of times for each color and sequentially acquiring image data of each color, the carriage moves forward and backward for exposure scanning. The return operation to return to the predetermined position must be repeated, and unless this series of image reading operations is efficiently executed, the load on the microcomputer (CPU) for controlling this operation increases.
[0004]
SUMMARY OF THE INVENTION An object of the present invention is to provide a microcomputer for controlling a series of image reading operations when forming a color image by continuously scanning a single original plural times for each color and sequentially acquiring image data of each color. It is an object of the present invention to provide an electrophotographic image forming apparatus capable of reducing the burden on the user.
[0005]
[Means for Solving the Problems]
The invention according to claim 1 has a light source, a drive source, and an optical system for exposing and scanning the original with light emitted from the light source. A scanning optical device that continuously scans a plurality of times for each color, a photoelectric conversion device that receives reflected light of the original and obtains a plurality of color-specific image signals for the same original, a photoconductor, and the same original on the photoconductor. An exposure device for sequentially optically writing an electrostatic latent image based on an image signal of each color, a developing device for sequentially developing the electrostatic latent image with toner of each color, an intermediate transfer member, and a toner of each color after the development. A first transfer device for sequentially superimposing and transferring an image to the intermediate transfer member, a second transfer device for transferring the superimposed toner image from the intermediate transfer member onto a sheet to form an image, and the original The original size of the paper Paper size, or by controlling the operation of said drive source in accordance with specification of the operation contents of said driving source that is determined in advance based on the magnification ratio when the image forming is performed from the original, the scanning of the plurality of colors And a microcomputer that executes sequentially.
[0006]
Therefore, since the details of the operation contents of the driving source such as the acceleration time of the scanning optical device, the approach distance, the scanning distance, and the way of return have been obtained in advance, the microcomputer determines that the scanning of the next color is completed after the scanning of one color is completed. Before scanning, there is no need to calculate details of the operation contents of the drive source for the scanning of the next color.
[0007]
According to a second aspect of the present invention, in the first aspect of the present invention, the microcomputer controls the operation of the drive source when sequentially performing scanning of a plurality of colors, with or without shading correction. For each of the above, when the scanning optical device moves to scan the document and when the scanning optical device returns to a predetermined position to start the next scan after scanning of one color of the document , the document size The details of necessary operation contents obtained in advance based on the paper size or the scaling ratio are used.
[0008]
Therefore, in each of the case where the shading correction is performed and the case where the shading correction is not performed, the microcomputer is used to move the scanning optical device for scanning the document and to start the next scanning after the scanning of one color of the document is completed. When the scanning optical device returns to a predetermined position, by using details of necessary operation contents obtained in advance, after scanning of one color is completed and before scanning of the next color, driving of the next color is performed. There is no need to calculate details of the operation of the source.
[0009]
According to a third aspect of the present invention, in the first or second aspect, an input device for designating a magnification of image formation, and reading of a document by a scanning optical device fixed in advance for each magnification. Storage means for storing a start position; and setting means for setting the reading start position to one of those stored in the storage means according to the designated magnification.
[0010]
Therefore, the reading start position of the document can be fixed according to the magnification of image formation.
[0011]
In the first, second, and third aspects of the present invention, the details of the operation may be calculated in advance by a microcomputer before starting the exposure operation of each color on a single document, or may be calculated in advance. Alternatively, the table may be stored in a ROM or the like of a microcomputer as a table, and this table may be looked up.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0013]
FIG. 1 is a longitudinal sectional view schematically showing a digital color copying machine to which the image forming apparatus of the present invention is applied. As shown in FIG. 1, the digital color copying machine 1 includes a scanner unit 2 and a printer unit 3.
[0014]
The scanner unit 2 includes a contact glass 39 on which the original G is placed, and a white reference plate 4 which is a substantially white member of uniform density provided in the main scanning direction of the original G to obtain correction data for shading correction. A light source 5 for irradiating the reading surface at a certain angle with respect to the white reference plate 4 or the contact glass 39, and implementing the photoelectric conversion device of the present invention. A CCD 29 for photoelectrically converting a certain optical image signal, and mirrors 6, 7 and 8 and a lens 9 for implementing the optical image signal from the white reference plate 4 and the original G on the CCD 29, for implementing the scanning optical apparatus of the present invention. , Is provided. The light source 5 and the mirror 6 are attached to a first carriage (not shown), and the mirrors 7 and 8 are attached to a second carriage (not shown). A motor 38 (not shown in FIG. 1) implementing the drive source of the present invention (see FIG. 2). ), The original G is exposed and scanned.
[0015]
This exposure scanning is repeated three times for a single document G, and an image for each color separation light of red (R), green (G), and blue (B) is sequentially read by each scanning. The color-separated image signal is subjected to color conversion processing by an image processing unit (not shown) to obtain digital image data of black (K), cyan (C), magenta (M), and yellow (Y). Further, the image processing unit performs predetermined shading correction, gamma correction, and other processing on the digital image data. The scanner unit 2 also performs a scaling process, a processing process, and the like designated by the user.
[0016]
The printer unit 3 includes a photosensitive drum 10, around which a charging charger 11 for forming an image according to an electrophotographic process, an optical writing optical unit 12, a developing unit 13, an intermediate transfer belt 14, a transfer charger 15, a cleaning unit 16, a neutralization lamp 17, and the like are sequentially arranged.
[0017]
The charging charger 11 charges the photosensitive drum 10.
[0018]
The optical writing optical unit 12 implements the exposure apparatus of the present invention. The optical writing optical unit 12 applies digital image data of black (K), cyan (C), magenta (M), and yellow (Y) to the photosensitive drum 10. Optical writing is performed sequentially.
[0019]
The developing unit 13 implements the developing device of the present invention, is a rotary type having a shape like a revolver, and includes four developing tanks 20, 21, 22, and 23 therein. Each of the developing tanks has therein a developer of four colors of K, C, M and Y. A developing bias is applied to the developing sleeve in each of the developing tanks 20, 21, 22, and 23, and toner is supplied onto the image carrier 2 so that the photosensitive drum 10 is sequentially optically written. , C, M, and Y are sequentially developed with the toner of the color.
[0020]
The transfer belt 14 implements the intermediate transfer member of the present invention. The toner image developed on the photosensitive drum 10 as described above is transferred to the transfer charger 15 that implements the first transfer device of the present invention. Is transferred. By repeating the above-described steps of charging, exposing, developing, and transferring four colors in the order of K, C, M, and Y, a superimposed image is formed on the transfer belt 14 using four color toners. Is done.
[0021]
The corona discharge transfer device 24 implements the second transfer device of the present invention, and transfers a four-color superimposed toner image on the transfer belt 14 to a sheet supplied from a sheet cassette (not shown). The transport belt 25 transports the sheet on which the toner image has been transferred to the fixing device 26. The fixing device 26 includes a pair of rollers 27 and 28, and heats and presses the superimposed image of the toner on the sheet conveyed by the transport belt 25 to fix the image to obtain a final created image. When a single color copy is performed, the steps of exposure scanning of the original G, the above-described charging, exposure, development, and transfer are performed only once, and a single color image is formed with K toner.
[0022]
FIG. 2 is a block diagram showing an electrical connection of a control system of the digital color copying machine 1. As shown in FIG. 2, the main control unit 30 is a microcomputer that controls the entire digital color copying machine 1, and allows the user to input various instructions such as setting of the number of copies and designation of scaling. 1 is connected to a display panel 32 such as an LCD for displaying various messages.
[0023]
The scanner control section 33 implements the microcomputer of the present invention. The ROM 34 and the RAM 36 are connected to the CPU 34 via a bus, and the motor driver 37 is also connected. The motor 38 that drives the first and second carriages (not shown) is connected to the motor driver 37. Various actuators, circuits, and sensors (not shown) are also connected to the scanner control unit 33. The scanner control unit 33 controls the entire scanner unit 2 under the control of the main control unit 30.
[0024]
The image reading process by the scanner unit 2 when copying the original G in the digital color copying machine 1 described above will be described with reference to the flowchart shown in FIG. The scanner control unit 33 starts the image reading process shown in FIG. 3 upon receiving an image reading command from the main control unit 30.
[0025]
In this image reading process, first, before starting the exposure scanning of the original G, the CPU 34 determines the first size (not shown) based on the size of the original G, the size of the paper, the magnification specified by the user on the operation panel 31, and the like. Secondly, a description (profile) of the operation contents of the motor 38 such as the acceleration time of the carriage, the approach distance, the scan distance, and the way of return is created (step S1).
[0026]
This profile is created from four types of “FromHP”, “FromMV”, “ToHP”, and “ToMV”. That is, “FromHP” is a profile when the first and second carriages (not shown) move forward from their home positions (positions for reading the position of the symbol HP shown in FIG. 1) for exposure scanning of the document G, and “FromMV” is The profile when the first and second carriages (not shown) move forward from the home position for exposure scanning of the original G without performing shading correction, and "ToHP" indicates the first and second carriages (not shown) move from the home position to the home position HP. The profile for the backward movement, "ToMV", is a profile for the case where the first and second carriages (not shown) return to the operation start point required for the next exposure scan without performing shading correction.
[0027]
If the copy to be executed is a single color (Y in step S2), "FromHP" and "ToHP" are selected because shading correction is required in each reading operation of the document G (step S3). , And controls the motor 38 according to “FromHP” and “ToHP” to read the original G (step S9). That is, the first and second carriages start exposure scanning from the home position, read the white reference plate 4 for shading correction, and then read the original G. Thereafter, the first and second carriages return to the home position for the next copy.
[0028]
When performing color copying (N in step S2), “FromHP” and “ToMV” are selected as those necessary for the first reading among the readings of R, G, and B colors (step S4). Y, S5), the motor 38 is controlled in accordance with “FromHP” and “ToMV” to read the original G (step S9). That is, since the first color is read, the first and second carriages start exposure scanning from the home position, read the white reference plate 4 for shading correction, and then read the original G. Thereafter, the first and second carriages move back for reading the next color. However, in reading the second color, it is not necessary to newly read the white reference plate 4 for shading correction. The carriage is moved back to the operation start point required for the exposure scan of the second color instead of the home position.
[0029]
Next, since the first reading has only been completed, the necessary profiles, that is, “FromMV” and “ToMV” are selected before the reading of the second color of the document G is performed (N in step S10, step S10). (N in S4, N in step S6, step S9). Then, the document G is read by controlling the motor 38 according to “FromMV” and “ToMV” (step S9). That is, the exposure scanning of the second color of the document G is executed without reading the white reference plate 4. Since the reading of the white reference plate 4 is not required in the next exposure scan of the third color, the first and second carriages are moved back to the operation start point required for the exposure scan of the second color instead of the home position. I do.
[0030]
Then, prior to execution of the last third reading of the document G, necessary profiles, that is, “FromMV” and “ToHP” are selected (N in Step S10, N in Step S4, Y in Step S6, Step S6). S9). Then, the document G is read by controlling the motor 38 in accordance with “FromMV” and “ToHP” (step S9). That is, the exposure scanning of the third color of the original G is performed without reading the white reference plate 4. Thereafter, the first and second carriages are moved back to their home positions for the next copy operation, and the process is terminated (Y in step S10).
[0031]
As described above, the profiles such as the acceleration time, the approach distance, the scan distance, and the return method of the mirrors 6, 7, and 8 moved by the first and second carriages are obtained by reading all the three colors of R, G, and B. Since it is obtained in advance, the scanner control unit 33 does not need to calculate a profile relating to the scanning of the next color after the scanning of one color is completed and before scanning of the next color. Therefore, it is possible to reduce the burden on (the CPU 34 of) the scanner control unit 33 that must perform control to return the first and second carriages to the predetermined position after the end of scanning for one color.
[0032]
In addition, the user can specify a magnification when copying by operating the operation panel 31 that implements the input device of the present invention. The calculation of the profile is performed after a process of selecting a reading operation start position of the original G when shading correction is not performed based on a certain magnification in accordance with the magnification is performed. Perform S1).
[0033]
FIG. 4 is a flowchart of the reading start position setting process. As shown in FIG. 4, the magnification ratio designated by the operation of the operation panel 31 is compared with the magnification ratio MAG1. When the magnification ratio is equal to or larger than the magnification ratio MAG1, the reading start position of the document G is set in advance. The reading start position POS1 stored in the ROM 35 that implements the storage means is selected (N in step S11, step S12). If the size is smaller than the magnification MAG1, the reading start position of the document G is previously stored in the ROM 35. The stored reading start position POS2 is selected (Y in step S11, step S13), and the process ends. This implements the setting means of the present invention. Then, after the end of this processing, the flow shifts to the processing of FIG. 3 described above, and the calculation of the profile (step S1) is performed. The reading start positions POS1 and POS2 are calculated in advance so as not to hinder the reading operation. The calculation of the profile can be easily performed by fixing the reading operation start position at which the first and second carriages start moving forward. Therefore, the reading start position is set to POS1 or POS2 according to the magnification. It is decided to fix to.
[0034]
【The invention's effect】
According to the first aspect of the invention, since the details of the operation contents of the drive source such as the acceleration time, the approach distance, the scan distance, and the return method of the scanning optical device are obtained in advance, the microcomputer scans one color. It is not necessary to calculate the details of the operation of the drive source for the scanning of the next color after the scanning of the next color after the completion of the scanning, so that the scanning optical device is moved to a predetermined position after the scanning of one color is completed. The load on (the CPU of) the microcomputer that must perform the return control can be reduced.
[0035]
According to a second aspect of the present invention, in the first aspect, the microcomputer determines whether or not the scanning optical device moves for scanning the original and whether or not the shading correction is performed. When the scanning optical device returns to a predetermined position in order to start the next scan after the end of scanning for one color, the details of the necessary operation contents obtained in advance are used, Before scanning the next color, there is no need to calculate the details of the operation of the drive source for the scanning of the next color. Therefore, control for returning the scanning optical device to a predetermined position after the scanning of one color is completed. The burden on (the CPU of) the microcomputer that must be performed can be reduced.
[0036]
According to a third aspect of the present invention, in accordance with the first or second aspect of the present invention, since the reading start position of the document can be fixed in accordance with the magnification of image formation, the details of the operation of the drive source are calculated. It is easier to do.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view schematically showing a digital color copying machine according to an embodiment of the present invention.
FIG. 2 is a block diagram showing an electrical connection of a control system of the digital color copying machine.
FIG. 3 is a flowchart of an image reading process performed by the digital color copying machine.
FIG. 4 is a flowchart of a reading start position setting process performed by the digital color copying machine.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Image forming apparatus 5 Light source 6, 7, 8 Scanning optical equipment 9a Photoelectric conversion device 10 Photoconductor 12 Exposure device 13 Developing device 14 Intermediate transfer member 15 First transfer device 24 Second transfer device 29 Photoelectric conversion device 31 Input device 33 microcomputer 35 storage means

Claims (3)

A light source,
A driving source,
A scanning optical device that has an optical system for exposing and scanning the original with light emitted from the light source and scans a single original continuously multiple times by color by moving the position by driving the driving source;
A photoelectric conversion device that receives reflected light of the document and obtains a plurality of color-specific image signals for the same document;
A photoreceptor,
An exposure device for sequentially optically writing an electrostatic latent image based on an image signal of each color for the same original on the photosensitive body,
A developing device for sequentially developing the electrostatic latent image with toner of each color;
An intermediate transfer member,
A first transfer device that transfers the toner images of the respective colors after development onto the intermediate transfer member in a superimposed order;
A second transfer device that transfers the superimposed toner image from the intermediate transfer member onto a sheet to form an image ,
The operation of the drive source is controlled in accordance with the details of the operation content of the drive source previously determined based on the original size of the original, the paper size of the paper, and the magnification when the image is formed from the original. A microcomputer for sequentially executing the scanning of the plurality of colors,
An image forming apparatus comprising: The microcomputer controls the operation of the driving source when sequentially performing scanning of a plurality of colors, when performing scanning shading correction and when not performing shading correction, when the scanning optical apparatus moves for scanning the original, and When the scanning optical device returns to a predetermined position in order to start the next scan after the end of scanning for one color of the original, it is necessary to obtain in advance the original size, the paper size, and the magnification based on the original size. The image forming apparatus according to claim 1, wherein a description of an operation content is used. An input device for designating a magnification of image formation;
Storage means for storing a reading start position of a document by a scanning optical device fixed in advance for each magnification,
Setting means for setting the reading start position to one of those stored in the storage means according to the designated scaling factor;
The image forming apparatus according to claim 1, further comprising:

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