JPH10274817A - Image forming device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the first copy time at the time of enlargement copy formation and the copy productivity per time, and to eliminate obstacles such as image blur in a color copying machine of a color sequential image forming method, and to reduce a first copy time. Another object of the present invention is to provide an image forming apparatus in which the copy productivity per time is improved and the color enlarged copy image area is enlarged. In an image forming apparatus having a function of forming an image by scaling a document image, a first carriage (208) that scans an approach section and a document, and a speed of V at the same magnification and a scaling factor of m. When the first carriage 208 scans the original at a speed of V / m to form a magnified image of m times, control is performed so that the speed in the approaching section is higher than the original image scanning speed V / m. An image forming apparatus including the scanning control unit 239.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a black-and-white electrophotographic copying machine, a color electrophotographic copying machine, and a facsimile, and more particularly to an image forming apparatus having a function of forming an enlarged image.

[0002]

2. Description of the Related Art In recent years, the maximum range of an enlarged copying magnification required for an image forming apparatus such as a copying machine has been widened, for example, to 400% or 800%. However, in a copying machine of the scanning exposure type, a high-magnification copy has a low scanning speed, so the run-up section before reading a document also adversely affects the processing time, and the first copy time and copy productivity per time are simply reduced by the magnification. There was a drawback that the delay was inversely proportional. For example, Japanese Patent Application Laid-Open No. 4-81807 is known as a proposal for improving copy productivity per unit time. According to this, the copy productivity is improved, but there is a problem that the value fluctuates. No improvement was made for the first copy time.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art. The first problem is that the first copy time at the time of forming an enlarged copy and the copy productivity per time are reduced. An object of the present invention is to provide an improved image forming apparatus. A second object is to provide an image forming apparatus in which the area of an enlarged copy image is enlarged by a color copying machine of a color sequential image forming method. The third problem is that the color copying machine of the color sequential image forming method eliminates obstacles such as image blur, improves the first copy time at the time of enlargement copy formation, improves the copy productivity per time, and provides a color enlarged copy image. An object of the present invention is to provide an image forming apparatus having an enlarged area.

[0004]

According to a first aspect of the present invention, there is provided an image forming apparatus having a function of scaling a document image to form an image. And an original image scanning means for scanning the original, and an original image scanning means for scanning the original at a speed of V at the same magnification and at a speed of V / m at a magnification of m to form an enlarged image of m times. The speed in the approach section is the original image scanning speed V / m.
Scanning control means for performing control so as to perform scanning at a higher speed than the above. In the image forming apparatus according to the first aspect, the scanning control means causes the original image scanning means to scan the original at a speed of V at the same magnification and at a speed of V / m at a magnification of m to form an m-fold enlarged image. In this case, the speed in the approaching section is scanned at a speed higher than the original image scanning speed V / m, so that the first copy time and the copy productivity per time can be improved. As another means for solving the first problem, the invention according to claim 2 is the image forming apparatus according to claim 1, wherein the original image scanning means is formed at the time of forming an enlarged image more than at the time of forming a 1 × image. The scanning control means is configured so that the stop position of the original image is moved in advance to the leading end side of the original document, and the total of the shortened approach section and original image section is reciprocated. In the image forming apparatus according to the second aspect, in addition to the apparatus configuration according to the first aspect, the stop position of the original image scanning unit is set by the scanning control unit at the time of forming an enlarged image more than at the time of forming a 1 × image. The original processing section is moved in advance and the total length of the shortened approach section and original image section can be reciprocated, so that the entire processing is reduced by the amount of time required for the original image scanning means to pass through the approach section. Time can be shortened.

According to a third aspect of the present invention, there is provided an image forming apparatus, comprising:
The original is scanned by scanning the multi-color image of two to four colors sequentially for each color.
When forming images of respective colors and superimposing them to form a final color image, the scanning control means is configured to scan the original image scanning means by the number of colors of the multicolor formed image. . In the image forming apparatus according to claim 3, 2
When a multi-color image of four to four colors is sequentially scanned for each color to form an original image, and these images are superimposed to form a final color image, the original image scanning means corresponds to the number of colors of the multi-color formed image. At the speed of V at the same magnification, and V / m at the magnification of m
When the original is scanned at a speed of m and an m-times enlarged image is formed, the speed in the approaching section is scanned at a speed higher than the original image scanning speed V / m, so the first copy time and copy productivity per hour are improved. In addition, the effective copy image area can be enlarged. According to a fourth aspect of the present invention, there is provided an image forming apparatus according to the second aspect, wherein the multi-color image of two to four colors is sequentially scanned by the original in the image forming apparatus. When forming images of each color and superimposing them to form a final color image, the scanning control means is configured to reciprocate the original image scanning means by the number of colors of the multicolor formed image. Features. In the image forming apparatus according to the fourth aspect, the stop position is moved in advance so that the approach section of the original image scanning unit becomes shorter than that of the same-size image formation when forming the enlarged image. Since the original image scanning means scans a plurality of times by the number of colors of the multicolor formed image, the first copy time and copy productivity per time can be improved, and the effective copy image area can be enlarged.

According to a fifth aspect of the present invention, there is provided an image forming apparatus according to the first or third aspect of the present invention, wherein an enlargement ratio m
Irrespective of the above, the scanning control means is configured to make the speed of the original image scanning means in the approaching section equal to the scanning speed V at the same magnification. In the image forming apparatus according to the fifth aspect, since the original image scanning unit is run at the same speed as the scanning speed V of the same-size copy regardless of the enlargement ratio m in the approaching section, the side effect of image blur due to vibration or the like is eliminated. In addition to improving the first copy time and the copy productivity per time, the effective copy image area can be enlarged. As another means for solving the third problem, the invention described in claim 6 is based on claim 2 or 4.
In the image forming apparatus described in (1), when forming an m-fold enlarged image, the scanning control unit is configured to make a preliminary movement amount for shortening the approach section of the original image scanning unit proportional to an enlargement factor m. It is characterized by the following. According to the image forming apparatus of the sixth aspect, in the apparatus configuration of the second or fourth aspect, the preliminary movement amount for shortening the approach section is made proportional to the enlargement factor m, so that the side effect of image blur due to vibration or the like is eliminated, and the first copy is performed. In addition to improving time and copy productivity per hour, the effective copy image area can be increased.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing a schematic configuration of a main part of a color electrophotographic copying machine (hereinafter, referred to as a color copying machine or simply a copying machine), and FIG. 2 is a block diagram of a whole main part of the color copying machine. Is shown. First,
A general operation outline will be described with reference to FIGS. The copying machine according to the present embodiment mainly includes a scanner module 200,
Printer module 400, system control module 6
00. The scanner module 200 includes at least an image reading unit 200 rd that reads an original image by dividing the original image into pixels, a scanner control unit 230, and a basic image processing unit 300. The printer module 400 includes an image forming unit 410 that forms and outputs a permanent visible image on the recording medium 190 (190A, 190B, 190C) and a printer control unit 430. The system control module 600 includes a system control unit 630 and a key input unit 81
0 and a console means 800 comprising a bit map display means 820. The system control means 630 is a general microcomputer system including a microprocessor, a read / write memory, a read-only memory, and an interrupt controller.

In the copying machine of this embodiment, C (cyan),
M (magenta), Y (yellow) or K (black)
Color copy, R (red), G (green) or B
(Blue) secondary color copy and full color copy can be selectively formed. At the time of monochromatic copying, one original scanning and one image forming cycle synchronized with the original scanning are executed.
At the time of the next color copy and the full color copy, respectively, two or four document scans and two or four image forming cycles synchronized with the original scan are executed, and a final image is formed and output on a recording medium. In the scanner module 200 of FIG. 1, reference numeral 230 denotes a circuit board on which scanner control means is mounted, 202 denotes platen glass, 202S denotes an image tip reference position, 202SH denotes a shading correction white plate,
208 is a first carriage as a document scanning means, 209 is a second carriage, 203 is a document illumination lamp, 204A,
B and C are first, second and third mirrors respectively, 205 is an image forming lens, 205X is an optical axis of a lens, 207 is a power imaging device, 211 is a carriage home sensor, and 250 is a circuit on which an original image reading circuit is mounted. A board 300 is a circuit board on which the basic image processing means is mounted.

Referring to FIG. 2, CPU 231 is a microprocessor, RAM 233 is a read / write memory, RO
M236 is a read-only memory, INT232 is an interrupt controller, DV238 is an input / output circuit of a sensor and an actuator, SYNC234 is a first synchronization signal generator, DMA235 is a DMA controller, and FIFO2.
37 is a first-in first-out (first-in first-out) memory, symbol XTL is the first crystal oscillator, symbol BUS
Is a bus connecting each part. Reference numeral 239 denotes a scanning control unit. These operations will be described later. The scanner control unit 230 communicates with the system control module 600 or the printer module 400 using a predetermined protocol, controls the reading of the original image based on the command, and outputs the original image data.

The scanner control means 230 first receives the SCAN command from the system control means 600 and transmits the information to the scan control section 239. Scan control unit 239
Determines the content and sends information to the original image scanning motor 210 to move the first carriage 208 in the sub-scanning direction. The rotation of the original image scanning motor 210 is linked to the movement of the first carriage 208 in the sub-scanning direction (FIG. 4).
), The first carriage 208 is controlled so as to immediately reach the leading edge 202S of the original image a fixed time after reception, and at a predetermined sub-scanning speed. That is, image data is always output after a certain time from the command reception timing. For this purpose, a carriage home sensor 211 for detecting the reference position of the carriage is provided, calibration of the scanning reference position is performed every time, and the sub-scanning movement amount of the original image scanning motor 210 at one step angle (the first carriage 208) is used. Is set to 1/16 mm or less. A micro step driving method is used as a motor driving method. In this way, the scanning control unit 239 controls not only the scanning speed of the first carriage 208 as a document scanning unit but also the stop position. Further, for synchronization with respect to the period, one main scanning line is read in synchronization with the pulse train period ts1 generated by the SYNC 234 serving as the first synchronization signal generating means, and is read into the transmission buffer FIFO 237.

The printer module 400 on the data receiving side sequentially takes out the data at substantially the same cycle as the cycle ts1. Therefore, no matter how many times the original image is scanned, the original image data is always obtained after a certain period of time from the reception of the command, the positional relationship (registration) between the paper and the image is correctly maintained, and the color plate registration is maintained during color copying. Will be. The original 180 is placed on the platen 202 such that the copy surface is down and the reading start position is at the left end 202S of the platen. Imaging lens 205
Forms a reduced projection image of the original image on the light receiving surface of the imaging device 207. The imaging device 207 is provided with a power imaging function using a charge coupled device (CCD) or the like, and is covered with a red filter 475.
The main scanning is performed by a two-pixel one-dimensionally arrayed R imaging unit, a one-dimensionally arrayed G imaging unit of 4752 pixels covered by a green filter, and a one-dimensionally arrayed B imaging unit of 4752 pixels covered by a blue filter. The structure is such that three rows are arranged in parallel in a direction (a direction perpendicular to the plane of the drawing). The three scanning lines are almost close,
More specifically, this is equivalent to an interval of 4/16 mm in terms of 180 original images. The scanning direction of the one-dimensional imaging device is the main scanning, and the scanning direction is a direction orthogonal to the
4 is referred to as sub-scanning.

The illumination lamp 203 and the first mirror 204A are mounted on a first carriage 208, and the second mirror 204
B and the third mirror 204C are fixed to the second carriage 209. When reading the original image, the first carriage 208
Is the sub-scanning speed Vsub, and the second carriage 209 scans from the left end to the right end while maintaining the optical conjugate relationship by the original scanning motor 210 and the driving wire 210W at the half Vsub / 2 speed (sub-scanning). ) Is driven. As the original image scanning motor 210, a stepping motor is used. The sub-scanning speed Vsub is 8
The magnification is 1/8 times at the time of 00% enlargement copy, and 4 times at the time of 25% reduction copy. The interval is variable in 1% steps, and an arbitrary speed is selected by a command from another module.
The total number of pixels of the imaging device 207 is 4752, and the
The line is decomposed into 16 pixels / mm in terms of the original image, sampled, read out, and an analog voltage corresponding to the RGB reflected light in pixel units from the original image 180 is output. Thereafter, the digital signal is converted into an 8-bit digital signal by the A / D converter 252 shown in FIG. 2, that is, quantized into 256 gradations.
Output to the basic image processing means 300. A3 original picture 180
, 6720 scan lines are read, and the carriage 20
When 8 reaches the right end, turn the motor 210 in the opposite direction,
It returns to the home position 211, stops, and prepares for the next scan.

The spatial filter circuit 301 performs a smoothing process or a sharpening process. In general, when the original 180 is a halftone print, the former process is performed, and when the original is a text-only document, the latter process is performed. The selection can be made on the manuscript designation screen of the console 800 or the image area automatic separation circuit 31 described later.
Depends on the result of separation from zero. A scaling circuit 302 scales the image to a designated size between 25% and 800% in the main scanning direction. Note that the copy magnification in the sub-scanning direction is achieved by changing the image reading speed (sub-scanning speed) as described above. The color processing circuit 303 has a function of converting the original RGB signals into C, M, Y, and K image forming signals which are recording color signals obtained by performing a masking process. Further, a so-called adaptive color process such as a color process suitable for each of the character image and the grayscale image, such as a blackening process for a black character portion, is performed. If necessary, the RGB signals are output to the system control module 600 via the scanner control means 230 as they are. The gradation processing circuit 304 performs dither processing from any of the 8-bit C, M, Y, and K image signals to generate a 4-bit recording image signal.
Further, gradation conversion suitable for each of the character image and the grayscale image, that is, so-called adaptive gradation processing is performed. The automatic image area separation circuit 310 identifies a character image portion and a grayscale image portion on one original image on a pixel-by-pixel basis, and compares the result with the spatial filter circuit 30.
1. Output to the color processing circuit 303 and the gradation processing circuit 304.

FIG. 2 shows the printer control means 430. CPU 438 in the figure is a microprocessor, R
AM 433 is a read / write memory, ROM 437 is a read only memory, INT 432 is an interrupt controller, SYNC 436 is a second synchronization signal generator, × TL 43
Reference numeral 9 denotes a second crystal oscillator, DMA 431 denotes a DMA controller, FIFO 435 denotes a first-in first-out memory, DV434 denotes an input / output circuit of various actuators such as a sensor and a motor, 500 denotes a copy number counting device, and BUS denotes a component. It is a bus. The printer control unit 430 communicates with the system control module 600 or the scanner module 200 using a predetermined protocol.
Basically, image data is acquired for each main scanning line, all units in the module are coordinated and energized to form an image based on a print mode command, and the final image is output to the transfer paper 190. In the color printing mode, C, M, Y, K
This is a surface-sequential image forming method in which each color is formed on a surface basis, is superimposed on the intermediate transfer belt 415, and is transferred to the recording paper 190 to be a final image. Therefore, in the color copy mode, four scan requests are output to the system control module 600 or the scanner module 200 for one print.

The printer module 400 has a pixel density of 1/16 mm or 1/24 for both C and M, Y, and K input to the printer control means 430 in both main scanning and sub-scanning.
Based on the 2-bit print data of mm, a full-color visible image consisting of a dot pattern with a print dot density of 1/16 mm or 1/24 mm for each of the C, M, Y, and K colors is formed on the transfer paper in both main scanning and sub-scanning. Output. Selection of a dot having a recording dot density of 1/16 mm or 1/24 mm is designated in advance by a mode selection command. The default is a dot density of 1/16 mm. When the image forming cycle is started, first, the photosensitive drum 414 is rotated counterclockwise, and the intermediate transfer belt 415 is rotated clockwise by a drive motor (not shown). At the time of full-color copying, a C toner image is formed as the intermediate transfer belt 415 rotates,
The toner image formation, the Y toner image formation, and the K toner image formation are performed, and finally the intermediate transfer belt 4 is sequentially arranged in the order of C, M, Y, and K.
The toner image is formed so as to be superimposed on the toner image.

First, a C toner image is formed as follows. The charging scorotron 419 uniformly charges the photosensitive drum 414 with negative charges to -700 V by corona discharge. Subsequently, the laser diode 441 performs raster exposure based on the C signal. A recording signal for image formation is transmitted to the scanner module 200 in a general copy mode.
Supplied from Therefore, in the copy mode, a data request signal REQ for sending the recording image data is issued to the scanner module 200 after a predetermined time. The data request signal is issued when the leading edge detecting unit 426 detects a permanent image synchronization mark attached to the belt, in preparation for color registration, when forming a multi-color image such as a secondary color or a full color. To be issued. In the case of a single color copy, it may be issued at an arbitrary timing.

A recording signal is input to the FIFO 435, and a laser driving circuit 441DV as a recording control circuit controls the light emission of the laser diode 441 for each input pixel based on the recording signal. The recording signal is 4 bits per pixel. More specifically, at the time of the highest C density pixel, laser light is emitted for the entire main scanning width, and at the time of a white pixel, no light is emitted. It is like that. When the raster image is exposed in this manner, in the exposed portion on the photosensitive drum 414 that is initially uniformly charged, the charge proportional to the exposure light amount disappears, and an electrostatic latent image is formed. Developing device 42
The toner in 0C is negatively charged by agitation with the ferrite carrier, and the cyan developing roll 420C of the present developing apparatus is connected to a metal base layer of the photosensitive drum 414 by a power supply (not shown) with a negative DC potential and AC. Are biased to the superimposed potential. As a result, the photosensitive member 41
No toner adheres to the portion where the charge of No. 4 remains, and the C toner is adsorbed to the portion having no charge, that is, the exposed portion, and a C visible image similar to the latent image is formed.

As described above, when the toner image on the photosensitive drum 414 rotates counterclockwise and reaches the position facing the primary transfer brush 416, the intermediate transfer belt 415 is brought into contact with the photosensitive member and driven at a synchronous speed. Is transferred to the corona. A small amount of untransferred residual toner on the photosensitive drum 414 is cleaned by the cleaning device 421 in preparation for reuse of the photosensitive drum 414. The collected toner is stored in a waste toner tank (not shown) via a collection pipe. next,
Prior to performing the M image forming raster exposure based on the M signal, the assembly of the developing devices 420 is rotated counterclockwise,
The M developing roll 420M is made to face the photosensitive drum 414. Next, the permanent image synchronization mark attached to the belt is detected by the leading end detecting means 426, and the scanner module 200 is detected.
If a data request signal R indicating that the recording M image data should be sent after a predetermined time to the system control module 600,
Issue the EQ again. If the M signal is sent exactly in synchronization with this data request signal, M image exposure, development, and primary transfer are performed, and accurate color plate matching with the original existing C image, that is, the intermediate transfer belt The M image will correctly overlap the C image on 415.

When the M raster image is thus exposed, the exposed portion of the photosensitive drum 414, which is initially uniformly charged, loses the charge proportional to the amount of exposure light, forming an electrostatic latent image. Is done. The M toner in the developing device 420M is negatively charged, and the developer on the developing roller 420M of the present developing device is in contact with the photosensitive drum 414 and is biased to the same potential as that of the C development. Therefore, the toner does not adhere to the portion where the charge of the photoconductor 414 remains, and the M toner is attracted to the portion exposed by the M signal, and an M visible image similar to the electrostatic latent image is formed. Becomes Similarly, the Y image is formed on the C and M toner images, and the K image is formed on the C, M and Y images so as to be superimposed. In the copy mode, since the basic image processing circuit 300 performs UCR (under color removal) processing, there is little chance that one pixel is developed with all four colors of toner. The full-color image formed on the intermediate transfer belt 415 that has been rotated at least four times in this way is eventually transferred to the secondary transfer roller 417 by rotation.

On the other hand, when image formation is started, the transfer paper 1
Reference numeral 90 denotes a feeding roll 413 from either one of the two feeding units, ie, the cassette 412A and the manual feeding tray 412B.
A and 413B are fed by the feeding or conveying action and are waiting at the nip of the register roll pair 418R. Then, the intermediate transfer belt 41 is attached to the secondary transfer roller 417.
When the leading edge of the toner image on the sheet 5 is approaching, the register roll pair 418R is driven just as the leading edge of the transfer paper 190A coincides with the leading edge of the image, and registration of the paper and the image is performed. In this way, the transfer paper was superimposed on the image of the intermediate transfer belt 415 and was connected to the positive potential power supply.
It passes under the next transfer roller 417. At this time, the transfer paper is charged with a positive charge by the corona discharge current, and the toner image is transferred onto the transfer paper. Subsequently, when passing through an unillustrated static elimination core connected to a ground source disposed slightly to the left of the secondary transfer roller 417, the transfer paper discharges electric charges, and the attraction force between the intermediate transfer belt 415 and the transfer paper almost disappears. I do. Eventually, the weight of the transfer paper exceeds the attraction force, and the transfer paper 190 is separated from the intermediate transfer belt 415 and moves to the transport belt 422. The transfer paper carrying the toner image is sent to the fixing device 423 by the conveyor belt 422.

At this time, heat and pressure are applied to the heated nip portion between the fixing roll 423A and the backup roll 423B, and the toner is melted and cut into the fibers of the transfer paper 190 to fix the image. That is, a copy image is completed. Thereafter, the completed copy is sent out of the main body by the discharge roll pair 424. The discharged copy paper is stacked face up on a tray (not shown). In the case of double-sided copying, the switching roll 425 is moved rightward together with the deflection of the paper, pressed against the opposite transporting roll to temporarily reverse the transfer paper, and then guided to the double-sided copying / automatic paper feed cassette 412A by the transport roll pair 413H. Transfer paper 1 copied at this time
90A is stacked with the copy side up.

FIG. 3 shows a scanner module 200 having this configuration.
This is realized by the execution of the CPU 231 of the control program built in the ROM 236 of the read-only memory. Here, p260 and below are routines for executing a series of document scanning processes. In the motor acceleration control process of p267, the process is executed with a slightly modified version of p267A. This is shown in FIG. P267A in FIG. 8 is processed so as to realize the acceleration profile in FIG. FIG. 7 shows the storage contents of the memory ROM 236 and the RAM 233 referred to in this processing. In the memory map of FIG. 7, XCTM is a position counter of the first carriage 208. As shown in FIG.
The counter XCTR is cleared at the moment of crossing 1 and the first
When the carriage 208 returns further to the left, the count is advanced to a negative value, and when the carriage 208 advances to the right (document scanning direction), the count is advanced to a positive value. The unit of the count is 1/16 as described above.
It is 1 count in mm. Normally, the power counter XCTR is also cleared when the motor is stopped at p280 in FIG. The acceleration profile before reaching the leading edge of the document is stored in the memory ROM 236 as a table for each magnification.
These symbols and meanings are shown in FIG. Referring to FIG.
To describe the operation of 67A, firstly, the vehicle accelerates at an acceleration Am corresponding to the magnification at p267A1, checks whether the acceleration section X2m is completed at p267A2, and shifts to a constant speed running of the approach speed VA at p267A3. At p267A4, it is determined whether or not the approach section has been completed, and when the approach section has been completed, the process proceeds to the next process.

FIG. 5 shows an operation speed profile. Here, V0f0 is the speed in the scanning direction at the time of the reference 1: 1 copy, and V0r0 is the speed at the time of return. V1f0 is the speed in the scanning direction at the time of 4 × enlargement copy of the conventional method, and V1r0
Is the return speed. Further, V1f1 is the speed in the scanning direction at the time of quadruple enlargement copying of the present invention, and V1r1 is the speed at the time of return. The speed of the document scanning section is naturally the same as that of the conventional method, that is, V0f0 × (１ ／), but the speed V1f1s until reaching the leading edge of the document is faster than the speed V1f1s.
f0. Then, assuming that the approach section is X0, in the conventional method, about 4 × (X0) /
It takes V0f0 (second), but in this method, it is about (X0) / V0
f0 (second) is sufficient. Therefore, the first copy time is reduced by about 3 × (X0) / V0f0 (second), and the productivity of the continuous copy is improved accordingly. This state is shown in FIG. In this figure, t0 is the time required to form four single-color copies in succession in the conventional method, and t1 is the time required to copy the same number of copies of the same size in the method of the present invention. It is clear from this that the productivity has been improved. In the above example, the case of 4 times magnification is described, but other magnifications can be handled in the same manner.

In the flowchart of the operation shown in FIG. 3, the steps p250 and below are routines for executing a series of preprocessing for scanning a document. In the scan mode setting step of p252, a slightly modified version of p252A shown in FIG. Is done. Also, the memory ROM 236 referred to in this processing,
FIG. 12 shows the contents of the RAM 233. When this is executed, the preliminary advance processing V1f2p in FIG. 10 is executed. In p268, processing is performed so as to realize the speed profile V1f2 in FIG. Here, V0f0 is the speed in the scanning direction at the time of the reference 1: 1 copy, and V0r0 is the speed at the time of return. Here, the speed at the time of document scanning is V0f0.
V1f0 is the speed in the scanning direction at the time of the 4 × enlargement copy of the conventional method, and V1r0 is the speed at the time of return.

Further, V1f2 is the speed in the scanning direction at the time of the quadruple magnification copy of the present invention, and V1r2 is the speed at the time of return, and the speed profile is defined as a distance X4 corresponding to approximately 3/4 of X0 before the enlargement copy operation. It has advanced preliminary as shown by V1f2p. Naturally, the speed of the document scanning section is the same as that of the conventional method, and is V0f0 × (１ ／).
However, the scanning time at the same speed is equal to the preliminary advance amount 3 × (X
0) / 4 equivalent time, ie 3 × (X0) /
V0f0 (second) is reduced. Therefore, in the conventional method, about 4 × (X0) / V0f0
(Seconds), but in this method, it is about (X0) / V0f0
(Seconds). Therefore, the first copy time is shortened by about 3 × (X0) / V0f0 (second), and the productivity of continuous copy is accordingly improved as in the case of the first configuration. Further, in a copying machine of a type in which a multi-color image of two to four colors is sequentially scanned for each color to form an image of that color, and these are superimposed to form a final color image, an intermediate transfer member or It is necessary to circulate the recording medium. The circulation cycle is T (seconds), and the image forming speed is V (m
m / sec), V × T (mm) becomes the maximum image length. However, in general, an image cannot be formed during the time corresponding to the rising time of document scanning or the return time of the scanning device. Therefore, the image can be formed only for the effective scanning time excluding these. In the embodiment shown in FIG. 1, the diameter of the photosensitive drum 414 is 90 mm, and the circumference of the intermediate transfer belt 415 is twice the circumference of the drum, that is, 565.4 mm. At the same magnification, the effective scanning section excluding the rising time of document scanning and the return time of the scanning device is about 430 mm. However, when the enlargement ratio of the conventional method is increased, the rise time of the original scanning increases as the enlargement ratio increases. For example, when the magnification is four times larger, the effective scanning section is reduced to 360 mm, that is, the maximum image size is reduced to 360 mm. There was a disadvantage.

Therefore, in the configuration of the present invention, as shown in FIG. 14, when the scanner control means 230 forms an image magnified by m times, the approaching section of the first carriage 208 (from the stop position of the original image scanning means to the original image leading end position 202 s). Distance to reach)
Is controlled so that the original is scanned by the number of colors of the multicolor formed image at the speed V1 higher than the original image scanning speed V / m. Scanning for each color is performed in the same manner as described above, and thus description thereof is omitted. When the system control unit 630 issues a full-color copy command to the scanner module 200 and the printer module 400, the printer module 400 sends an image data request signal to the scanner module 200 every rotation of the intermediate transfer belt 415 regardless of the magnification. Issue to 200.

The request signal is issued four times in the case of full color. Scanner module 200 receiving this
Since the magnification is known in advance, the scanner control means 230 accelerates at the acceleration Am corresponding to the magnification at p267A1, checks whether the acceleration section X2m is completed at p267A2, and runs the constant speed of the approach speed VA at p267A3. Then, it is checked at p267A4 whether or not the approaching section has been completed. When the approaching section has been completed, the operation is shifted to the actual scan, the operation returns at the rear end of the document, and the operation is completed at home. This is repeated four times for convenience.
This control is achieved by the CPU 231 executing a processing program shown in FIG.
In FIG. 14, t0 is the effective scanning time (360
mm), and t1 is the effective scanning time (4
(Equivalent to 30 mm).

Another solution to the above problem is shown in FIG. 15 as a speed profile. When the enlargement color copy mode is set via the operation panel 820, the command is immediately communicated to the scanner module 200. When the scanner control unit 230 forms an m-times enlarged image, the preliminary advance processing V1f2p similar to FIG. Run. In the case of 4 times enlarged copy, the approach section is about 3 / X0
4 is preliminarily advanced by a distance X4. When the system control unit 630 issues a full-color copy command to the scanner module 200 and the printer module 400, the printer module 400 outputs the leading edge detection unit 426 every rotation of the intermediate transfer belt 415 regardless of the magnification.
Issues an image data request signal to the scanner module.

The request signal is issued four times in full color. Scanner module 200 receiving this
Since the control means 230 previously knows the magnification and the corresponding advance advance amount X4 in the process of p252A1 in FIG.
The value obtained by adding X4 / V1f2 (second) to the conventional effective scanning time is used as the effective scanning time. This is convenient 4
Repeat several times. This control is performed by the control shown in FIG.
Are achieved by the CPU 231 executing the processing program shown in FIG. In FIG. 15, t0 indicates the effective scanning time (time equivalent to 360 mm) in the conventional method, and t1 indicates the effective scanning time (time equivalent to 430 mm) in the present method.

Referring to FIG. 5, the speed profile shows an oscillating speed fluctuation at the rising portion. This is because, as can be seen in FIG. 4, a vibration system is formed in which two carriages 208, 209 having a relatively large mass are stretched by a motor 210 having magnetic compliance and two wires 210W having moderate compliance. Because it is. By the way, the approach distance of the carriage is generally a value obtained by adding the time required for accelerating the two masses and the settling time of the vibration. The amount of vibration is approximately proportional to the scanning speed as a result of the experiment. In general, the acceleration section accelerates at the maximum generated acceleration of the motor, and the control is simple. From the above, the approaching section can be shortened as the copy enlargement ratio becomes larger (as the scanning speed becomes lower).

However, according to the prior art, the distance of the approaching section is fixed irrespective of the copy magnification in order to avoid complicated control. In this case, as the enlargement ratio increases, the dead time increases, the first copy and copy productivity are degraded, and the effective image area of the color copy is reduced. In the present invention, paying attention to the fact that the amount of vibration is proportional to the scanning speed and the approaching section matches the same-size copy, the same speed profile as that of the same-size copy is also used for enlarged copy, and image blur due to vibration of the leading edge of the image is reduced. Avoid and maximize first copy and copy productivity. In order to realize this, the acceleration data VAm1, VAm of the approach section of each magnification stored in the ROM 236
2. . . VAmn, Am1, Am2. . . . Amn, X
2m1, X2m2. . . . X2mm, X3m1, X3m
2. . . . X3mn are almost the same, and the scanning speeds Vm1, Vm
m2. . . There is only a change of the minute adjustment amount required for different Vmn. However, since control is performed using this table, the intended purposes of improving the first copy and copy productivity and increasing the color copy area are achieved.

Also, the amount of vibration is approximately proportional to the scanning speed as a result of the experiment, and the dead time increases as the enlargement ratio increases, thereby deteriorating the first copy and copy productivity.
Also, reduction of the effective image area for color copying has been described above. In the present invention, attention is paid to the fact that the amount of vibration is proportional to the scanning speed and the approaching section matches the same-size copy.
In this way, the image blur due to the vibration of the leading edge of the image is avoided, and the first copy and copy productivity are improved to the maximum. ROM2 to realize this
In the program stored in 36, X4m = X0−X0 × (1 / m) is calculated in the process of p252A1 in FIG. 13, and the preliminary advance X4m is executed according to the calculated value. Therefore, the intended purposes of improving the first copy and copy productivity and expanding the color copy area are achieved.
In FIGS. 1 and 2, the scanning control unit 239 for controlling the driving of the first carriage 208 and the second carriage that moves with the first carriage 208 is set in the scanner control unit 230. It need not be in the means 230. Further, the scanning control unit 239 itself is replaced with a CP.
It can be shared by another microprocessor comprising U, ROM and RAM and its peripheral circuits.

[0033]

As described above, the present invention exhibits the following excellent effects. According to the image forming apparatus according to the first aspect of the invention, in the case of m-times enlarged image formation,
Since the scanning control unit controls the speed of the approaching section of the original image scanning unit to scan at a speed higher than the original image scanning speed V / m, the first copy time and copy productivity per time can be improved. According to the image forming apparatus of the second aspect, in addition to the first aspect, the stop position is set in advance so that the approaching section of the original image scanning unit is shorter when forming an enlarged image than when forming an equal-size image. Since it is moved, the time required to pass through the approach section can be shortened, and the first copy time and copy productivity per hour can be improved. According to the image forming apparatus according to the third aspect of the present invention, in addition to the first aspect, in the case of magnification-magnifying image formation, the speed of the approaching section of the original image scanning unit is set to be lower than the original image scanning speed by the scanning control unit. Is controlled so as to scan the multicolor image several times at a high speed, so that the first copy time and copy productivity per time can be improved, and the effective copy image area can be enlarged. According to the image forming apparatus of the fourth aspect, in addition to the second aspect, the stop position is set in advance so that the approaching section of the original image scanning unit is shorter when forming the enlarged image than when forming the same-size image. Since the original image scanning means scans the moving approach and the shortened approach section and image section a plurality of times by the number of colors of the multicolor formed image,
The first copy time and copy productivity per hour can be improved, and the effective copy image area can be increased. According to the image forming apparatus of the fifth aspect of the present invention, in addition to the first or third aspect, the speed of the original image scanning means in the approaching section is equal to the scanning speed V of the 1: 1 copy regardless of the enlargement factor m. As a result, the side effect of image blur due to vibration or the like is eliminated, the first copy time and copy productivity per time are improved, and the effective copy image area can be enlarged. According to the image forming apparatus of the sixth aspect, in addition to the second or fourth aspects, the preliminary movement amount for shortening the approaching section is proportional to the enlargement factor m, so that image blur due to vibration or the like can be prevented. Eliminating side effects, improving the first copy time and copy productivity per hour, and expanding the effective copy image area.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an entire main part of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a functional block diagram of a main part of the image forming apparatus according to the embodiment of the present invention.

FIG. 3 is a flowchart showing main operations of the scanner module according to the embodiment of the present invention.

FIG. 4 is a perspective view of a main mechanism of the scanner module.

FIG. 5 is an explanatory diagram of a document scanning speed according to claim 1;

FIG. 6 is an explanatory diagram of an approach section of the original image scanning means according to claim 1.

FIG. 7 is an explanatory diagram of contents of a memory for performing a main operation in a run-up section according to claim 1.

FIG. 8 is a detailed flowchart for explaining a main operation of the motor acceleration control according to the first embodiment.

FIG. 9 is an explanatory diagram of a document scanning speed during continuous copying according to claim 1;

FIG. 10 is an explanatory diagram of a document scanning speed according to claim 2 of the present invention.

FIG. 11 is an explanatory diagram of the approach section of the original image scanning means according to claim 2 of the present invention.

FIG. 12 is an explanatory diagram of the contents of a memory for performing a main operation in the approach section according to claim 2;

FIG. 13 is a detailed flowchart for explaining a main operation of a scan mode setting in claim 2.

FIG. 14 is an explanatory diagram of a document scanning speed according to claim 3;

FIG. 15 is an explanatory diagram of a document scanning speed according to claim 4.

[Description of Signs] 200 scanner module, 200rd image reading unit, 202 platen glass, 202S image tip reference position, 208 first carriage (original image scanning unit), 20
9 2nd carriage, 210 stepper motor, 21
1 Carriage Home Sensor, 230 Scanner Control Unit, 239 Scan Control Unit (Scan Control Unit), 300 Basic Image Processing Unit, 400 Printer Module, 410
Image forming unit, 430 Printer control means, 600 System control module

Claims (6)

[Claims] 1. An image forming apparatus having a function of scaling a document image to form an image, comprising: an original image scanning means for scanning the run-in section and the document;
When the original image scanning means is caused to scan the original at a speed of V / m at the time of forming a magnified image of m times, the scanning in the approach section is performed at a speed higher than the original image scanning speed V / m. An image forming apparatus, comprising: a scanning control unit for controlling. 2. When forming an enlarged image, the stop position of the original image scanning means is moved to the leading end side of the original document in advance compared with the case of forming an equal-size image, and the total of the shortened approach section and original image section is reciprocated. 2. The image forming apparatus according to claim 1, wherein the scanning control unit is configured as described above. 3. When the multicolor image of two to four colors is sequentially scanned for each color to form an image of each color and these are superimposed to form a final color image, the number of colors of the multicolor formed image 2. The scanning control unit according to claim 1, wherein the scanning control unit is configured to control the scanning of the original image scanning unit.
An image forming apparatus according to claim 1. 4. A multi-color image formed by sequentially scanning a multi-color image of two to four colors to form an image of each color and superimposing them to form a final color image. The image forming apparatus according to claim 2, wherein the scanning control unit is configured to reciprocate the original image scanning unit by a distance. 5. When forming an enlarged image of m times, said scanning control means so that the speed in the approaching section of said original image scanning means is equal to the scanning speed V at the same magnification regardless of the magnification ratio m. The image forming apparatus according to claim 1, wherein: 6. The scanning control means is configured such that, when forming an m-times enlarged image, a preliminary movement amount for shortening the approach section of the original image scanning means is proportional to an enlargement factor m. The image forming apparatus according to claim 2, wherein: