JPH03186865A - Color copying machine - Google Patents

Abstract

PURPOSE:To miniaturize a color copying machine, to reduce the cost thereof and to eliminate the superposing deviation of toner images of respective colors by providing a scanning start timing adjustment means which can set start timing every toner image of the respective colors. CONSTITUTION:A rotational position detection means 56 generates a rotational position signal every time that a rotating body is rotated once and a scanning control means 401 controls the start timing of scanning by setting the rotational position signal as a reference. Then, the start timing of the scanning is adjusted every color by the scanning start timing adjustment means 455 - 457 and an exposure position in a circumferential direction on a photosensitive body is adjusted every color. Thus, the color copying machine is miniaturized and the cost thereof is reduced. Besides, the superposing deviation of the toner images of the respective colors is eliminated and a color copied image with high quality is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color copying machine that forms a color copy image by superimposing toner images of a plurality of colors.

[Conventional technology]

Analog color copying machines use a single light source to scan to read the original and to expose to form a latent image on the photoreceptor. The scanner performs multiple scans, forms toner images of different colors for each scan, and superimposes the toner images of each color to form a color copy image corresponding to the original.

When forming a toner image, the scanning light that scans the original corresponding to the toner color is exposed to the photoreceptor through a color filter corresponding to the toner color. form an image.

Generally, three primary color toners, cyan (C), magenta (M), and yellow (Y), are used to form a color copy image.
, green (G), and blue (B) color filters perform color separation of the scanning light. In addition, black (BK
) toner to form a monochrome (black and white) copy image, or when forming a monochrome copy image consisting of a composite color obtained by combining the above-mentioned primary color toners, the exposure amount The photoreceptor is exposed to light through an ND filter for adjusting.

In conventional color copying machines, for example,
As shown in Japanese Patent No. 37505, the color filters and ND filters of each color can be selectively switched and arranged so as to cross the optical path of the scanning light, separately from the filter for guiding the scanning light to the photoreceptor. It is provided. That is, the scanning light is emitted from one side of one filter disposed in the optical path, passes through the inside of the filter, emerges from the other side of the filter, and heads toward the photoreceptor.

Therefore, in conventional color copying machines, the optical path of the scanning light is determined by a mirror fixed to a support member, and the exposure position on the photoreceptor can be adjusted by switching filters to form toner images of each color. It never shifts.

[Problem to be solved by the invention]

Incidentally, in recent years, there has been an increasing demand for smaller and cheaper color copying machines.

For this reason, color copying machines are being put into practical use that are smaller in size and lower in price by integrating the above-mentioned filters and mirrors to reduce the installation space and number of parts.

When an optical system for exposure is constructed using a filter mirror that integrates a filter and a mirror, the scanning light that enters from one side of the filter part of the filter mirror is reflected by a part of the filter part and passes through the filter. The light exits from the same side as the incident side of the part and heads towards the photoreceptor.

However, in a color copying machine that uses an optical system consisting of filter mirrors, when the filter mirrors corresponding to each color of toner are selectively switched in forming a color copy image, errors in the positioning of each filter occur. As a result, a shift occurs in the optical path of the scanning light, and the circumferential exposure position on the photoreceptor may differ for each filter mirror.

For this reason, there is a problem in that the difference in exposure position causes a misalignment (color misregistration) in the superposition of toner images of each color, resulting in a decrease in the quality of the color copy image.

In view of the above-mentioned problems, the present invention eliminates the misalignment of overlapping toner images of each color while reducing the size and cost.
The object of the present invention is to provide a color copying machine that can form high-quality color copy images.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides color copying in which a document is scanned multiple times and toner images of different colors are superimposed on a rotating body for each scan to form a color copy image. a rotational position detection means for generating a rotational position signal for each rotation of the rotating body; a scanning control means for controlling the start timing of scanning based on the rotational position signal; The present invention is characterized by comprising a scan start timing adjustment means that can be set for each image.

[Operation] A document is scanned a plurality of times, and toner images of different colors are superimposed on each scan on a rotating body to form a color copy image.

The rotational position detection means generates a rotational position signal every rotation of the rotating body.

The scan control means controls the scan start timing based on the rotational position signal.

The scan start timing adjusting means adjusts the scan start timing for each color, and thereby the circumferential exposure position on the photoreceptor is adjusted for each color.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional front view showing the general structure of a color copying machine 1. As shown in FIG.

Approximately in the center of the main body of the color copying machine 1 is a photosensitive drum 2.
is arranged so as to be rotatable in the clockwise direction, and the photosensitive drum 2
Surroundings are a cleaner unit 3, a main eraser lamp 4, a charger 5, and an LED as a partial eraser.
An array 6, developing units 7 to 10, and a transfer belt 11 as an intermediate transfer medium are provided. The photosensitive drum 2 is provided with a photosensitive layer on its surface, and the surface is uniformly charged by passing through a main eraser lamp 4 and a charging charger 5, and is charged by an optical system 40 (described later) to form a latent image. exposed to light.

Each developing device 7, 8, 9.10 has yellow (Y)
), magenta (M), cyan (C), black (BK)
Toner empty sensors 7a and 8a are used to detect the shortage of toner of each color.
, 9a, and 10a are provided.

Note that the developing units 7 to 10 are not limited to a type in which they are fixedly arranged around the photosensitive drum 2, but may be, for example, in a type in which the developing units 7 to 10 are integrated and movable in the vertical direction. Any type of toner may be used as long as it can selectively supply toner of different colors to the photoreceptor drum 2.

The transfer belt 11 is used to transfer (secondary transfer) the toner image developed on the photoreceptor drum 2 by the developing devices 7 to 10 onto a paper surface material (hereinafter referred to as "paper") P on which a copy image is to be formed. The photosensitive drum 2 is held by a plurality of rollers (not shown), and is supported so as to be rotatable in a counterclockwise direction while always being in contact with the photosensitive drum 2.

A transfer charger 12 for primary transferring a toner image from the photosensitive drum 2 and a rotational position sensor 56 for detecting the rotational angular position of the transfer heald 11 are fixedly arranged inside the transfer heald 11. . Rotational position sensor 5
A photo sensor 6 generates a rotational position signal 310 when it senses reflected light from a heald mark 57 provided at one location on the inner surface of the transfer heald II.

Further, around the outside of the transfer belt 11, a transfer charger 16 for secondarily transferring the toner image onto the paper P,
A separation charger 17 for separating the transfer belt 11 from the transfer belt 11 and a belt cleaner 15 for cleaning the outer surface of the transfer belt 11 are provided. The belt cleaner 15 can be pressed into contact with the transfer heald 11 (during cleaning) or separated from it. The optical system 40 is operated below the document platen glass 31 in the direction of arrow M5 (forward direction) and in the direction of arrow M6 (return direction).
A main lens 2 includes a scanner 50 that can be moved back and forth, a CCD 27 for color editing, and a lens 51 arranged nearby.
6. It is composed of a filter selection mechanism section 28 for enabling color separation exposure, a fixed mirror 29, etc., and scans the document sheet when the scanner 50 moves forward to expose the photosensitive drum 2.

The scanner 50 consists of a first slider 23 having an exposure lamp 24 and a mirror 41, and a second slider 52 having a mirror 42.43. For V, v
The second slider 52 is driven by the scan motor 70 to move forward at a speed of V/2n. The scanner home switch 71 is composed of a photo sensor, and outputs a signal indicating that the scanner 50 has returned to the reference position (home position) when the protrusion 73 of the first slider 23 faces the scanner home switch 71.

The filter selection mechanism section 28 includes a mirror 28ND that performs total reflection and three filter mirrors 28YB, 28MG, and 28CR that are radially provided at an angle of 90 degrees with respect to an axis 28a. By being rotated and positioned, one of these mirrors is selectively switched, and the selected mirror is configured to guide the scanning light to the exposure point of the photoreceptor drum 2 via the fixed mirror 29. There is. A mirror reference position sensor 25 is provided at the location where the selected mirror is to be positioned, and FIG. 1 shows a state in which the mirror 28ND has been selected and positioned.

Filter mirrors 28YB, 28MG, and 28CR are integrated mirrors and filters by depositing blue (B), green (G), and red (R) color separation filters on the mirror surface, respectively. ,
It is used for M and C color toners.

On the other hand, a paper cassette 32 containing paper P is attached to the lower left side of the color copy 4i11, and a paper ejection tray 3 containing paper P on which a copy image has been formed is attached to the lower right side.
3 is provided.

Paper P is fed one by one from the paper cassette 32 by the paper feed roller 21, is transported by the timing roller 20 in synchronization with the transfer belt 11, and after the toner image is secondarily transferred from the transfer belt 11, the paper P is fed out one by one by the paper feed roller 21 from the paper cassette 32. 18 to the fixing unit 19. A paper size sensor 13 is provided near the paper feed roller 21 to detect the size of the paper P, and a timing sensor 14 is provided near the timing roller 20 to detect the leading edge position of the paper P passing therethrough. ing.

The fixing unit 19 includes a fixing roller 54, a fixing heater lamp 55 for heating, and the like, and fuses the toner image to fix it on the paper P. The paper P on which a copy image is formed by fixing the toner image is discharged onto the paper discharge tray 33 by a discharge roller 53 .

In addition, the main motor 2 is located in the center of the left side of the color copier l.
2 are arranged, and the main motor 22 drives the above-mentioned photosensitive drum 2, transfer belt 11, paper feed roller 21,
Timing roller 20, conveyor belt 18, fixing roller 5
4, a paper ejection roller 53, and the like are rotationally driven.

In the color copying machine 1 configured as above, the above-mentioned Y
, M, C, and BK, and R (Y and M), G ( Y and C), monochrome copy images of the base of B (M and C), and 3
It is possible to form a color (full color) copy image obtained by superimposing toner images of primary colors.

In forming single toner color and composite monochrome copy images, the mirror 28ND is used to expose and scan the original, and the latent image formed on the photoreceptor drum 2 is developed in accordance with the specified color. The toner image is developed using any one of the containers 7 to 10 and transferred onto the transfer belt 11. Furthermore, in the case of a monochrome copy image at the base, exposure scanning is performed again on the same original by the mirror 28ND, and any one of the developing devices 7 to IO, which is different from the previous one, is used for compositing. The developed toner image is transferred to a transfer belt (11), and the two color toner images are superimposed on the transfer belt (11).

In addition, the color copy image is obtained by scanning the same document multiple times according to a well-known color electrophotographic process, and filter mirrors 28VB, 28MG, 28C are scanned for each scan.
R and the developing devices 7 to 9 are selectively switched to form and develop a latent image in which the document is color separated, and the toner images are sequentially transferred to the transfer belt 11, and the toner images of each color are formed on the transfer belt 11. It is formed by overlapping.

When overlapping toner images (hereinafter referred to as "multiple transfer"), it is necessary to transfer each toner image to the same position on the transfer belt 11. Therefore, in the color copying machine 1 of this embodiment, the above-mentioned rotational position Rotational position signal 3 from sensor 56
The start timing of movement of the scanner 50, that is, the start timing of forming a latent image on the photoreceptor drum 2 is controlled based on the generation timing of 10.

FIG. 20 is a diagram showing how the photosensitive drum 2 is exposed.

In the color copying machine 1, in order to simplify the optical system 40, the filter selection mechanism section 28 is configured by the filter mirrors 28Y828MG and 28CR, which are integrated with a mirror and a filter for color separation, as described above. The mirror that determines the optical path of the light is movable.

For this reason, filter mirrors 28YB and 28MG.

Due to variations in accuracy or variations in stop position (stop angle) when switching between filter mirrors 28YB, 28MG, 28CR1 and mirror 28ND, the mounting of 28CR on the base requires four mirrors: 28YB, 28MG, 28CR.
, 28ND, there may be a shift in the exposure point on the photosensitive drum 2.

In the figure, as an example, a filter mirror 28YB,
Each exposure point θy of 28MG.

θm is shown.

In the case where a shift occurs in the exposure point, if the start timing of each scan with respect to the above-mentioned rotational position signal SIO is the same, the transfer position of each toner image to the transfer bell 1-11 will shift, causing color shift in the copied image. This will cause the image quality to deteriorate.

Therefore, in the color copying machine 1, the rotational position signal S1
The start timing of scanning for 0 is set for each color 28YB,
It is said that it can be adjusted for each 28MG, 28CR, and 28ND.

In the following explanation, the mirror 28ND, filter mirrors 28YB, 2.8MG, and 28CR will be referred to as ND filter, B filter, G filter, and 28CR, respectively, based on color separation characteristics.
It is sometimes called an R filter.

FIG. 2 is a plan view of the operation panel ○P provided on the top surface of the color copying machine 1.

On the right side of the operation panel OP, there are a print key 200 for starting the copying operation, a numeric keypad 202 for setting copy conditions such as the number of copies, a 7-segment LF and D201 for displaying the number of copies, and a clear stop. key 203, interrupt key 204, magnification up and down keys 205, 206 for setting the copy magnification,
3-digit 7-segment display that displays copy magnification h L E D
207, up and down keys 210, 208 for manually setting the density of a copied image step by step, an LED 211 for displaying the density level of a copied image, an auto density setting key 209, an auto density display LED 222, etc. in normal copying operations. Keys used and display LEDs are arranged.

Also, on the left side of the operation panel ○P, Y, MC, BK
LED223Y, 2 to indicate the shortage of toner of each color.
23M, 223G, 2238K, LED 224a that indicates whether the waste toner storage container is full, interrupt display LED 224b, paper P jam display LED 224
c. Each color (Y
, M, C, R, G.

Color keys 225 to 231 corresponding to B, BK), full color key 232 for specifying color copying, ○HP
An OHP key 233 is used when a transparent sheet for (over-height projector) is used as the paper P, and a book key 234 is used when copying the left and right pages of a double-page spread of a book etc. on two sheets of paper P. , and each key 22
LED 235 for display corresponding to each of 5 to 234
~244 are arranged.

In addition, in the following explanation, color keys 225, 226.2
27, 228, 229, 230, and 231 are sometimes referred to as the Y key, M key, C key, R key, C key, B key, and BK plain key, respectively.

FIG. 3 is a block diagram of a control circuit 400 of a color copying machine.

The control circuit 400 includes a CPU that controls the overall operation of the color copying machine 1 (a central processing bag 401, a scan motor control 452 that controls the drive of the scanner 50, and a control circuit that controls the movement of the main lens 26 in accordance with the copying magnification). It is mainly composed of a lens motor control 453 and a filter mirror motor control 454 that performs switching control of the filter selection mechanism section 28.

A switch matrix 450 in which various operation keys on the operation panel OP, toner empty sensors 7a to 10a, etc. are arranged vertically and horizontally is connected to the CPU 401.

The 7-segment 15ED 201 and display LEDs related to operation mode and color designation are connected through the switch matrix 450 and decoder 451, and their lighting or extinguishing is controlled.

Further, the output signals and rotational position signal SIO of the above-mentioned paper size sensor 13 and typing sensor 14 are input to the input terminal of the CPU 401, and the signals are connected to the output terminal based on the signals from each of these sensors and the switch matrix 450. The main motor 22, various clutches such as a developing clutch, each charger, the exposure lamp 24, etc. are controlled to be turned on or off.

Furthermore, the CPU 401 includes a B filter, a G) filter,
Three sets of dip switches 455, 456, and 457 are connected to adjust the above-mentioned deviation of the exposure point when the R filter is selectively switched and used. That is, the scan start timing for forming each Y, M, and C toner image can be changed in eight steps with respect to the generation timing of the rotational position signal SIO.

As a result, in the color copying machine 1, the exposure points corresponding to the B filter, G filter, and R filter can be corrected so as to match the exposure points of the reference ND filter, and high quality images without color shift can be achieved. It becomes possible to form a color copy image.

Next, the operation of the color copying machine 1 will be explained with reference to flowcharts shown in FIGS. 4 to 18.

FIG. 4 is a main flowchart schematically showing the operation of the CPU 401.

When the power is turned on and the program starts, first,
In step #1, registers and peripheral interfaces are initialized, and in step #2, an internal timer for defining the length of one routine of the CPU 401 is set.

In step #3, manual key processing is performed to receive and receive signals from the operation keys on the operation panel OP, and in step #4,
Executes display processing for displaying on the operation panel OP.

Next, paper feeding/feeding processing (step #5) that controls the paper feeding and transport of paper P, image creation processing (step #6) related to the electrophotographic process, and scanning for scanning the original document. A series of copy sequence processes consisting of the process (step #7) is executed.

After executing these processes, an internal timer is waited in step #8, and the process returns to step #2. As a result, the length of the I routine is kept constant, and each process from step #2 to step #8 is repeated while the power is turned on.

FIG. 5 is a flowchart of the key manual processing in step #3.

Steps #11 to #18 are key one-day processing corresponding to the operation keys that specify the color of the copy image, and in each step, the monochrome mode for each single toner color of Y, M, and C is sequentially performed. , RGB monochrome mode, full color mode, and BK monocolor mode (corresponding to black and white copying).

In step #19, OHP key processing is performed, and in step #20, other key processing is performed.

FIG. 6 is a flowchart of the Y key processing in step #11.

First, in step #26, it is checked whether or not the Y key 225 has been pressed (hereinafter referred to as "on-check"), and if no, the process returns directly.

If YES in step #26, in step #27,
An empty check is performed to determine the presence or absence of Y toner (not insufficient, but insufficient), and if YES, the process returns directly. If no in step #27, that is,
If Y toner is present, in step #28, a Y copy mode is set in which monochrome copying is performed using only Y toner.

0 Although not shown, in the M key processing and C key processing in step #12 and step #13 in FIG. A check is performed, and if the check conditions are met, M copy mode or Y copy mode is set.

FIG. 7 is a flowchart of the R key processing in step #14 of FIG.

First, in step #30, the R key is checked, and if YES, an empty check of the Y toner is performed in step #3I.

If there is Y toner, an empty check of M toner is performed in step '#33. If both Y toner and M toner are present, in step #35, an R copy mode is set in which the Y toner image and the M toner image are superimposed.

On the other hand, if it is determined that there is no Y toner in the check in step #31, an empty check is performed for the M toner in step #32, and if there is M toner even though there is no Y toner, the M toner is checked in step #34. Set the M copy mode, which performs monochrome copying using only toner.

In other words, R (red) and M (magenta) are visually similar colors, so even if it is impossible to color R due to a lack of Y toner, pressing the R key will not be ignored.
M copy mode is set as an alternative to R copy mode. If both Y toner and M toner are empty, no copy mode is set even though the R key is pressed.

FIG. 8 is a flowchart of the G key processing in step #15 of FIG.

First, in step #40, the G key is checked, and if YES, step #41T: Y toner empty check is performed.

If there is Y toner, an empty check of C toner is performed in step #42. If both Y toner and C toner are present, in step #43, a C copy mode is set in which the Y toner image and the C toner image are superimposed.

On the other hand, if the answer is YES in step #40 and step #41, the process returns without setting the copy mode.

In other words, G (green) and Y (yellow), and G and C
(Cyan) is generally not considered a similar color, so G
It is not possible to use a single color of Y or C as an alternative. Therefore, if either the Y toner or the C toner is in short supply, no copy mode is set for either color.

FIG. 9 is a flowchart of the B key processing in step #16 of FIG.

First, in step #50, the B key is checked, and if YES, an empty check of the C toner is performed in step #51.

If there is C toner, an empty check of M toner is performed in step #52. If both C toner and M toner are present, in step #54, a B copy mode is set in which the C toner image and the M toner image are superimposed.

3 If YES in step #52, that is, if there is C toner and there is no M toner, then in step #53,
Set the C copy mode, which performs monochrome copying using only toner.

In other words, since B (red) and C are visually similar colors, even if it is impossible to color B due to a lack of M toner, you can use the B copy mode without ignoring the press of the B key. C copy mode is set as an alternative.

FIG. 1O is a flowchart of the full color key processing in step #17 of FIG.

First, in step #60, the full color key 232 is checked, and if YES, an empty check is performed for each of Y, M, and C toners in sequence in steps #61 to #63.

If all YM and C toners are present, step #6
In step 4, a full color mode is set in which Y, M, and C toner images are superimposed.

If even one color of toner among Y, M, and C is insufficient,
Since it is impossible to form a color copy image, the process returns without setting the pull color mode.

FIG. 11 is a flowchart of the BK key processing at step #18 in FIG.

First, in step #70, a BK main key on check is performed, and if YES, a BK main key empty check is performed in step #71.

If there is BK toner, in step #76,
Sets the BK copy mode in which monochrome copying is performed using only the B11 color.

On the other hand, if YES in step #71, Y, M in step gaff 2 to step #74.

Empty check of each toner of C is executed sequentially.

If all Y, M, and C toners are present, step #
75, Y formed sequentially using mirror 28ND
, M, and C toner images are set.

In other words, in the color copying machine 1, in addition to the three primary color toners for forming color copy images, if there is a shortage of BK toner, which is mainly provided for forming black and white copy images, black and white copies will be made. As an alternative, toners of the three primary colors may be used to form a black and white copy image without prohibiting the above.

FIG. 12 is a flowchart of the HP key processing in step #19 of FIG.

First, in step #80, the OHP key 233 is turned on. If YES in step #80, then in step #81 it is checked whether the OHP mode has already been set.

If YES in step #81, O in step #82.
Cancel HP mode, and if no in step #81,
In step #83, the OHP mode is set.

Here, the ○HP mode is an operation mode in which the system speed of the entire electrophotographic process is made slower than in the normal operation mode, and as a result, the time for the paper P to pass through the fixing unit 19 is increased, and the paper P is overlapped. The plurality of toner images are sufficiently melted and mixed, and the translucency of the color copy image is enhanced.

In addition, in the color copying machine 1 of this embodiment, a timer is provided to measure a predetermined time when returning from the HP mode to the normal operation mode, to ensure that the state of each part related to the electrophotographic process is stabilized. The apparatus is configured to wait before starting operations associated with the electrophotographic process, thereby avoiding disturbances in the copied image due to poor cleaning or poor toner agitation, or automatic shutdown of the system due to detection of defects.

FIG. 13 is a flowchart of the display processing of step #4 in FIG.

In step #90, toner empty sensor 7a~
Based on the signal from 10a, a 1-toner empty process is executed to display the shortage of each toner on the operation panel OP, and in step #91, a color specification display process is executed to display a color corresponding to the color specification of the copy image. Execute.

After executing these processes, other display processes are performed in step #92.

FIG. 14 is a flowchart of the toner empty processing in step #90.

First, in step #100, an empty check of the Y toner is performed. If YES in step #100, the LED 223Y is turned on in step #101, and if NO in step #100, the LED 223Y is turned off in step #102.

Similarly, in step #103, an empty check is performed for the M toner, and if YES, the LED 223M is turned on in step #104, and if NO in step #103, the LED 223M is turned off in step #105.

Next, in step #106, an empty check of the C toner is performed, and if YES, the LED 223C is turned on in step #107, and if NO in step #106, the LED 223C is turned off in step #108.

Finally, in step #109, perform an empty check on the BKI-ner, and if yes, step #110
The LED 223BK is turned on in step #109, and if the answer is NO in step #109, the LED 223BK is turned off in step #111.

FIG. 15 is a flowchart 1 of the color designation display process in step #9 of FIG. 13.

In this routine, first, in steps #120 to #125, a check is sequentially performed to determine whether a copy mode corresponding to each monochrome color of Y, M, C, R, G, and B is set.

If YES in each of steps #120 to #125, steps #126 to #13 are used to display that each copy mode has been set.
1 lights up the LEDs 235 to 240, respectively.

If the answer is NO in any of steps #120 to #125, the process moves to step #132 and checks whether the full color mode is set. Step #
If 132 is YES, step #135 turns on LED2.
42 is lit.

If no in step #132, a check is made to see if the BK copy mode is set in step #133, and if yes, the LED 24 is set in step #136.
Turn on 1.

Also, if no in step #133, step #1
Check whether the 3-color overlay mode is set in step #134, and if yes, turn on the LED in step #137.
241 flashes.

If the LED 241 flashes, the operator should
It is determined whether or not the color overlapping mode is acceptable, and if it is acceptable, the print key 200 is pressed to start printing. If not, replenish the black toner and then specify the BK mode again. In other words,
In the color copying machine 1, when there is a shortage of black toner, the operator determines whether to form a black copy image by using the three primary color toners or to form a black copy image by using the black toner after replenishment. You can choose.

FIG. 16 is a flowchart of the paper feeding/paper passing process in step #5 of FIG.

In this routine, first, in step #140, the state indicated by the count value of the state count is checked, and the following processing is executed depending on the state.

In the initial state immediately after the power is turned on and in the standby state after the copying operation is completed, the state is "0".

In state "0", first, Ste Knob #141
Then, the print key 200 is checked, and if the result is no, the process returns to the main routine.

If YES in step #141, step #142
The main motor 22 is turned on to start rotating each part.

Next, in step #143, a main motor start-up timer is set to wait for the rotation of the main motor 22 to stabilize, and in step #145, the state is set to "1".

In state "1", the main motor start-up timer is counted up in step #150. As a result, each time step #150 is executed, the count number of the main motor start-up timer is updated, and timekeeping progresses.

2 In the following step #151, check whether the count number of the main motor start-up timer has reached a predetermined value, that is, check whether the timer has finished counting, and if no, return; if step #51 is yes, For example, the state is updated to "2" in step #152.

In state "2", in step #160, the paper feed roller 21 is turned on to feed the paper P into the conveyance path, and the state is set to "3" (step #161).

In state "3", the timing sensor 14 is checked in step #170.

If YES in step #170, step #171
Turn off the timing roller 20 and continue with step #17.
Step #2 sets a paper loop timer for registration alignment, and step #173 sets the state to "4".

In state "4", the paper loop timer is counted up in step #180, and the count-up is performed in step #180.
At step 181, the end of the paper loop timer is confirmed.

If step #18■ is YES, step #182
Turn off the paper feed roller 21 and set the state to "5" (
Step #183).

In state "5", it is determined in step #190 whether or not it is the timing to register the paper P with respect to the toner image on the transfer heald 11.

If YES in step #190, the timing roller 20 is turned on to advance the conveyance of the paper P (step #19
1).

In the following step #192, it is checked whether the mode is OHP mode or not. If it is the OHP mode, it is necessary to reduce the speed at which the paper P passes through the fixing unit 19, so the process moves to step #195 and the state is changed to " 9”.

If NO in step #192, set a paper feed interval timer to keep the intervals between sheets P constant in the transport path (step #193), and set the state to "6" (step #193).
Step #194).

In state "6", the paper feed interval timer is counted up in step #200, and the count-up is performed in step #20.
Step 1 confirms that the paper feed interval timer has ended. If the paper feed interval timer has ended, the state is set to “
7”.

In state "7", in step #210, it is checked whether multi-copying in which the number of copies is two or more is specified by the operation panel OP.

In the case of multi-copy, the state is returned to "2" in step #211, and in the case of single copy where the number of copies is one, the state is updated to "8" in step #212.

In state "8", wait until all the fed sheets P are ejected to the paper ejection tray 33, and proceed to step #22.
0, and when completion of paper ejection is confirmed based on a signal from a paper ejection sensor (not shown), the main motor 22 is turned off in step #221 and the state is returned to "0" (step #221).
222).

0 HP in step #192 of state "5" mentioned above
If it is determined that the mode is set, the processing from state "9" to state 1-rllJ is executed.

In state "9", first, step #230 checks whether the toner image of one color or a plurality of colors has been secondarily transferred from the transfer heald 11 to the paper P depending on the timing of the process.

If YES in step #230, step #131
As described above, in order to lengthen the passage time (heating time) of the paper P through the fixing unit 19, the fixing roller 54 is
The rotational speed of the main motor 22 that drives the main motor 22 is reduced.

Note that it is also possible to maintain the rotational speed of the main motor 22 at a normal speed and reduce only the rotational speed of the fixing roller 54 using a clutch or the like.

Thereafter, in step #232, the state is set to "10".

In state "10", in step #240, it is confirmed that the OHP paper P that has passed through the fixing unit 19 at low speed is ejected, and in step #241, the rotational speed of the main motor 22 is returned to the normal speed. do.

Next, in step #242, a process stability timer is set to wait for the state of each part related to the electrophotographic process to become stable, and in step #243, the state is changed to "
11”.

In state "11", the process stability timer is counted up in step #250, and the end of the process stability timer is confirmed in step #251.

If step #251 is YES, step #522
Returns the state to "7" and returns to the main routine.

FIG. 17 is a flowchart of the image forming process in step #6 of FIG.

First, in step #300, the state is checked, and the following processing is executed according to each state from state "20" to state "35".

In state "20", first, print key 20 is pressed.
0 is checked (step #301).

If step #301 is YES, follow step #3
At step 02, the charger 5, main routine amplifier 4, etc. are turned on to prepare for the electrophotographic process.

Next, in step #303, the copy number counter is set to "0".
'' and advances the state to ``21j.'' The copy number counter is for counting the number of secondary transfers from the transfer heald 11 to the paper P.

In state "21", it is checked in step #311 whether a mode for multiple transfer is set.

If no in step #311, that is, if a copy image is to be formed using toner of one color, step #3
Proceed to step 12.

On the other hand, when performing multiple transfer, it is necessary to perform multiple scans in synchronization with the rotation of the transfer belt 11, so the state is advanced to "26" in step #315.

In step #312, the filter selection mechanism section 28 selects N.
Select the D filter to define the optical path for exposure.

Next, in step #313, the heald cleaner 15 is turned on to clean the transfer belt 11, and the state is advanced to "22" (step #314).

In state "22", the exposure lamp 24 is turned on (Step #321), the developing clutch of any one of the developing devices 7 to IO is turned on (Step #322) according to the set copy mode, and the exposure lamp 24 is turned on (Step #322). Set the exposure lamp start-up timer to wait for the light amount to stabilize (step #323), and set the state to "23" (step #323).
Step #324).

In state "23", the exposure lamp rising timer is counted and amplified in step #331, and the completion of the exposure lamp rising timer is confirmed in step #332.

If YES in step #332, step #333
Then, the scanner start signal 320 for starting the forward movement of the scanner 50 is output, and step #
At 334, the state is set to "24".

In state "24", the end of scanning is confirmed in step #341, and if YES, the exposure lamp 24 is turned off and the developing clutch turned on in step #342L is turned off (step #343).

Next, in step #344, it is checked whether or not it is multi-copy, and if it is multi-copy, step #34 is executed.
5, the state is set to "25", and in the case of single copy, the state is returned to the initial value "20" in step #346.

In state "25", it is checked in step #351 whether the return of the scanner 50 has been completed, and if the return has been completed, the state is set to "22" in step #352.

As mentioned above, step #311 of stay) r21J
If it is determined that the mode is for multiple transfer, the processes in states "26" to "35" are executed.

In state "26", the number of colors to be combined is checked in step #361.

If there are two colors in step #361, the bottom monocolor (R
, GB), select the ND filter (step #362), set the scan counter to "2" indicating the number of scans for one copy image (step #363), and set the state to "27". Proceed (step #364).

On the other hand, if there are 3 colors in step #261, step #3
65 to check whether the mode is full color mode.

In the case of full color mode, first select the B filter to form a Y toner image (step #366);
If it is not the full color mode, that is, if it is the three-color superimposed mode, an ND filter is selected (step 436B).
).

After executing step #366 or step #368, in step #367, the scan counter is set to "3" and the state is updated.

In state "27", it is checked in step #371 whether the rotational position signal 310 has been generated, that is, whether the heald mark 57 of the transfer heald 11 has been detected. If YES in step #371, an exposure lamp on timer for determining the lighting timing of the exposure lamp 24 is set in step #372, and the state is advanced to "28" (step #373).

In other words, the transfer bell 11 is rotated at a constant speed, and the cycle of generation of the rotational position signal S10 is constant. Therefore, in the color copying machine 1, in a scan that is started based on the generation timing of the rotational position signal SIO,
In order to keep the light amount of the exposure lamp 24 stable, an exposure lamp on timer is provided to turn on the exposure lamp 24 at a certain time based on the generation timing of the rotational position signal SIO immediately before the start of scanning. ing.

This makes it possible to prevent unnecessary lighting of the exposure lamp 24 and to prevent scanning when the amount of light is unstable.

In stay 1-r28J, in step #381,
The exposure lamp on timer is turned on, and in step #382, the end of the exposure lamp on timer is confirmed.

If YES in step #382, the exposure lamp 24 is turned on (step #383), the developing clutch is turned on (step #384), and the stay 1 is set to "29" (step #385).

In state r29J, in step #391, it is checked whether the rotational position signal SIO is generated.

If YES in step #39I, the exposure lamp on timer is set in step #392 in order to determine the lighting time of the exposure lamp 24 in the second and subsequent scans in the same way as described above, and in step #393 , outputs a scanner start signal S20. After that, the state is set to "30" (step #394).

In state "30", first, step #401
to confirm the completion of scanning.

If the scan is completed, the subsequent steps #402 to #415 are executed.

That is, turning off the exposure lamp 24 (step #402)
, Turning off the developing franchise while it is being driven (steer).

#403), scan counter countdown (
After sequentially executing step #404), it is checked whether the value of the scan counter is "0" (step #405).

If YES in step #405, it means that the copying operation for one sheet of paper P has been completed, so step #405
At step 06, count amplification of the copy number counter is performed.

Next, in step #407, it is checked whether the value of the copy number counter has reached 10, and if no,
The process moves to step #415 and advances the state to "34".

If the answer is yes in step #407, the number of copies counter is reset (step #408), the heald cleaner 15 is turned on (step #409), and the cleaning time (one rotation time of the transfer belt 113) is measured. After sequentially executing the belt cleaning timer setting (step #410), the state is advanced to "33J" in step #411.

In other words, when multi-copy is specified, in the mode that performs multiple transfer, that is, full color mode, composite color (R, G, B) copy mode, and 3-color overlapping mode, the same copy on the transfer bell) 11 Multiple sheets of paper P at the position
A toner image corresponding to each of the images is formed. Therefore, even if some toner remains on the transfer belt 11 after the secondary transfer, the effect on the next sheet P is small.
Although it is not necessary to clean the transfer belt 11 for each sheet of paper P, if residual toner accumulates, there is a risk that the quality of the copied image will deteriorate. Therefore, in the color copying machine 1, the number of secondary transfers is counted by a copy number counter, and
The electrophotographic process is interrupted every 10 sheets of paper P, and the transfer belt 11 is cleaned.

On the other hand, if the answer in step #405 is NO, the process proceeds to step #412, where it is checked whether the mode is full color mode.

If it is not the full color mode, the state advances to "31" in step #414. In the case of full color mode, in step #4J3, the filter is switched to select a G filter or an R filter depending on the color of the toner image to be formed next, and then the process proceeds to step #414.

In state "31", in step #421, it is checked whether scanning is possible every time the rotational position signal SIO is generated, with reference to a scan table TS, which will be described later, related to paper size and copying magnification.

If YES in step #421, follow step #4
At step 22, in order to determine whether scanning is possible each time the rotational position signal SIO is generated in relation to the book mode, it is checked whether the next scan is a scan of the 8th side of the book.

The 8th side of the book refers to the scan direction (M
5) When the document sheet is divided into two sides using the center as a boundary, this is the side farthest from the home position of the scanner 50. Note that the closer side is the book A side, and in the book mode, the book side and the book 8 side are each copied onto separate sheets P.

If no in step #422, step #423
Then return the state to "28J" and wait for the next lighting timing of the exposure lamp 24.

Also, if step #421 is NO and step #4
If the answer is YES in step #424, the state advances to "32".

In state "32", in step #431, it is checked whether the rotational position signal S10 is generated.

If YES in step #431, step #432
After setting the exposure lamp on timer, the scan start signal S20 is activated, unlike the state "29" described above.
The state is returned to "28" in the following step #433 without outputting.

That is, in this case, the rotational position signal 310 is invalidated with respect to the start of the scan.

FIG. 19 is a diagram showing the contents of scan table TS.

The scan table TS scans the paper P on the document table glass 31.
The reciprocating time of the scanner 50 determined by the mutual relationship between the size and feeding direction of the paper and the copying magnification set by the numeric keypad 202, etc. is determined in advance, and the number of occurrences of the rotational position W signal 310 (which is a necessary condition for starting scanning) "1" or "
2) is stored as data.

In the notation of paper size in the same figure, for example, A3
FtM refers to the case where A3 size paper P is fed with its longitudinal direction as the transport direction, and A4 landscape refers to the case where A4 size paper P is fed with its longitudinal direction perpendicular to the transport direction. say.

In the color copying machine 1, the peripheral length of the transfer heald 11 is 450 mm.
mm, and the system speed in normal operating mode is 110 mm/sec.

Therefore, the time for one rotation of the transfer belt 11 (the period of generation of the rotational position signal SIQ) is 4.09 seconds, which is 8 1 .

On the other hand, in the scanner 50, the time required for reciprocating movement consisting of each period of acceleration, constant speed, and deceleration is, for example, 3.0 seconds (
Forward movement is 2.2 seconds, backward movement is 0°8 seconds), and in this case, the movement time is shorter than the generation period of signal S10, so
Scanning can be started continuously each time the signal SIO is generated (every rotation of the transfer belt).

On the other hand, even when copying at the same size, in the case of A3 portrait paper P, the reciprocating time of the scanner 50 is 5
．． 4 seconds (4.2 seconds for forward movement, 1.2 seconds for backward movement), which is longer than the generation cycle of signal 310, so scanning cannot be started continuously every time signal S10 occurs. Therefore, in this case, signal SIO is invalidated every other time of its occurrence, as described above, and scanning is started every second occurrence of signal 310.

Further, even when using paper P of the same size, the reciprocating time differs depending on the copying magnification.

In other words, the scan table TS generates a rotational position signal, which is a condition for starting scanning, in association with a copying condition consisting of the size and feeding direction of the paper P on the document table glass 31, and the copying magnification set by the numeric keypad 202, etc. The number of occurrences of SIO ("1" or "2") is determined in advance.

Returning to FIG. 11, in state "33", the heald cleaning timer is counted up in step #441, and the end of the belt cleaning timer is confirmed in step #442.

If YES in step #442, step #443
Turn off belt cleaner 15 and repeat step #40 above.
The cleaning of the transfer heald 11 started at step 9 is completed.

Thereafter, in step #444, the state is updated to "34".

In state "34", in step #451 it is checked whether there is a copy request prompting the next copying operation, and if there is no copy request, the process moves to step #453 and the state is returned to the initial value "20".

As a result, the color copying machine 1 enters a standby state.

If there is a copy request, the state is advanced to "35" in step #452.

In state "35", it is checked in step #461 whether the return of the scanner 50 has been completed.

If YES in step #461, the state is returned to "26" in step #462 in order to move on to the next copying operation.

FIG. 18 is a flowchart of the scan process of step #7 in FIG.

First, in step #500, the state is checked, and the following processing is executed according to each state from state "40" to state "43".

In state "40", first, step #501
Check the presence or absence of the scanner start signal S20,
If yes, proceed to step #502.

In step #502, the optical system 40 checks the filter selected in accordance with the toner color, and subsequent processing branches depending on the filter.

If an ND filter is selected, step #5
The program advances to 03, updates the state to "41", and returns.

If the B filter is selected, before the state update, in step #504, a B delay timer is set with a clock time set based on the timing correction by the dip switch 455 described above.

Further, if the G filter is selected and the R filter is selected, step #50 is performed, respectively.
5. Proceed to step #506, and in each step, the state is updated after setting the G delay timer and the R delay timer whose clock times are set by dip switches 456 and 466.

In state "41", in step #511, the set delay timer is counted up,
At step #512, the end of the delay timer is confirmed.

If step #512 is YES, step #513
Then, the scan motor 70 starts forward movement of the scanner 50, and the state is set to "42".

Note that in step #512, if the ND filter is selected, it is assumed that the timer has ended, and the answer is YES.

In state "42", it is determined in step #521 whether or not the scanner 50, which is moving forward, has reached the rear end of the document tray and has finished scanning.

If the scanning is completed, the scanner 50 starts returning at step #522 and advances the state to "43" (step #523).

In state "43", the scanner 50 waits for return to the home position, and when the completion of the return is confirmed in step #524, the state is returned to the initial value "40" in step #525.

According to the above-described embodiment, when switching from the OHP mode for increasing the translucency of the copied image to the normal copying mode, the electrophotographic process is stopped until a predetermined period of time has elapsed for the state of each part to stabilize. Since this is prohibited, it is possible to form high-quality copied images under stable process conditions at all times.

In the above-mentioned embodiment, a color copying machine l of an intermediate transfer method is provided in which a transfer belt 11 as an intermediate transfer medium is provided between the photosensitive drum 2 and the paper P, and toner images of each color are superimposed on the transfer belt 11. As an example, as a method of superimposing toner images, a method is performed on copy paper wrapped around a rotating body such as a transfer drum, or a method is performed on a photosensitive drum (for example, Japanese Patent Laid-Open No. 61-32854). The present invention can also be applied to color copying machines that employ the following.

〔Effect of the invention〕

According to the present invention, it is possible to provide a color copying machine that is compact and inexpensive, eliminates misalignment of toner images of each color, and is capable of forming high-quality color copies.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional front view showing the general configuration of a color copying machine;
FIG. 2 is a plan view of the operation panel provided on the top of the color copying machine, and FIG. 3 is a block diagram of the control section of the color copying machine.
4 to 18 are flowcharts showing the operation of the color copying machine, FIG. 19 is a diagram showing the contents of the scan table,
FIG. 20 is a diagram showing how the photosensitive drum is exposed. ■...Color copying machine, 2...Photoconductor drum (rotating body), 11...Transfer belt (rotating body), 56...Rotation position sensor (rotation position detection means), 401...CP
U (scanning control means), 455-457... dip switch (scanning start timing adjusting means), D... document, S10... rotational position signal.

Claims (1)

[Claims] (1) In a color copying machine that scans a document multiple times and forms a color copy image by superimposing toner images of different colors on a rotary body for each scan, one revolution of the rotary body. a scanning control means that controls the start timing of scanning based on the rotational position signal; and a scanning start device that allows the start timing to be set for each color toner image. 1. A color copying machine comprising: timing adjustment means.