JPH02162367A - Image forming device - Google Patents

Abstract

PURPOSE:To facilitate the adjustment of a filing margin or the adjustment of a resist by calculating the standby stop position of a scanning optical system based on the instructed adjusting quantity of the filing margin, etc., and adjusting the moving speed of a transfer paper holding body so that the calculated value is satisfied. CONSTITUTION:By inputting the instruction of the movement of an image, the stop position of the scanning optical system is previously changed by nXi with reference to an original home position based on the input of deviation value Xi by a correction data input part 33. It is assumed that (n) is a constant fixed according to a variable magnification ratio. An exposure scanning start time (t) is set at a time t(s) sin a reference mode. When a copying action is started and a mark detecting sensor S1 on a transfer drum 18 outputs with the lapse of time (t), the scanning optical system 9 is started. When a sensor S2 on the going-path of the scanning optical system 9 outputs with the lapse of time T2, which is read by a CPU 32 to calculate the correction value of the transfer drum 18 from the difference from the point of time T3 calculated from the stop position of the scanning optical system. On the arrival of a compensation start timing, the speed of the drum 18 is adjusted.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an image forming apparatus.

[Conventional technology]

The image forming apparatus includes a transparent document placing table on which a document is placed, a scanning optical system that is placed opposite to this document placing table and which scans the document on the document placing table, and a scanning optical system that scans the document on the document placing table. A photoreceptor that moves and carries an electrostatic latent image while being irradiated with a reflected light image from an original on a placing table; a developing means that visualizes the electrostatic latent image on the photoreceptor into a toner image; A transfer paper holder disposed facing each other and capable of attaching and detaching the transfer paper; a driving means for independently driving the scanning optical system, the photoreceptor, and the transfer paper holder; There is a device that repeatedly transfers the toner image on the photoreceptor to the transfer paper on the transfer paper holder by repeatedly operating the photoreceptor a plurality of times to create a copy of the original.

An example of such an image forming apparatus is a so-called transfer type color copying machine.

In other words, a scanning optical system, a photoconductor drum with a photoconductor formed on the circumference of the drum, and a transfer drum with a transfer paper holder formed in the shape of a drum are each driven by nine independent motors, and the original is transferred multiple times. The color separated image obtained on the photoreceptor drum by scanning illumination is developed with complementary color 1 hener, and the developed toner image is sequentially transferred to transfer paper wrapped around the transfer drum to obtain a superimposed color image. However, it is a color copying machine.

In such a color copying machine, when making a copy of an original placed at a predetermined position on the document table, the scanning optical system is used to form the image on the transfer paper at the same correct position on the original. , the drive timing between the photoreceptor [ram] and the transfer drum is controlled.

A mode that implements such control is hereinafter referred to as a standard mode. Therefore, under the standard mode, the image position from the outer edge of the document and the image position from the outer edge of the transfer paper are, in principle, coincident.

The reason why we have decided to never, in principle, is that due to unavoidable manufacturing errors in the manufacturing stage of the optical system and other parts, constant deviations between the transfer paper and the image occur each time the transfer is performed. This is because it can occur.

[Problem to be solved by the invention]

There is a demand from users for so-called binding margin adjustment, in which they want to create a margin for binding by intentionally shifting the position of an image created on transfer paper.

On the other hand, on the manufacturer's side, as described above, there is a need for so-called resist adjustment in order to eliminate a certain misalignment between the transfer paper and the image that occurs in the standard mode due to manufacturing errors.

In general, in regular black-and-white copying machines that do not require precise overlapping of multiple images on transfer paper, when performing binding margin adjustment or registration adjustment, simply change the start timing of the scanning optical system or the timing of the start of conveyance of the transfer paper. You can achieve your goal just by letting them do it.

On the other hand, in an image forming apparatus such as the above-mentioned color copying machine that performs single-layer transfer, the positional relationships between the scanning optical system and the photoreceptor, and between the photoreceptor and the transfer paper holder must be precisely maintained in predetermined relationships. Therefore, although it has a control function for this purpose, it does not have a specific means for binding margin adjustment or registration adjustment, and it simply delays the timing to the star 1 of the scanning optical system, resulting in overlapping transfer. If precise timing control is not performed each time, there will be problems such as transfer deviation and loss of copy quality, and it is difficult to easily adjust the timing.

Therefore, an object of the present invention is to provide an image forming apparatus that can easily perform binding margin adjustment and registration adjustment.

[Means to solve the problem]

In order to achieve the above object, the image forming apparatus of the present invention includes a first sensor S for detecting marks on a transfer paper holder, and a second sensor S2 disposed on the forward movement path of the scanning optical system. and a correction in which the deviation between the theoretical value and the actual value of the time from the mark detection time T2 by the first sensor S1 to the detection time T3 during forward movement of the scanning optical system by the second sensor S2 is determined as a correction value Δt. A value calculation means and an instruction means for instructing an arbitrary movement amount of the toner image to be formed on the transfer paper are provided, and when the movement amount is instructed by the instruction means, the scanning optical system After changing the standby stop position before the start of scanning, the correction value Δt corresponding to this change is calculated, and the speed of the transfer paper holder is adjusted to compensate for this correction value Δt, and the next toner image and transfer paper are adjusted. It is designed to perform alignment with the

[For production]

The adjustment amount of the binding margin etc. is instructed by the instruction means, and based on this instruction, the standby stop position of the scanning optical system before the start of scanning is calculated, and the actual moving speed of the transfer paper holder is adjusted to match this calculated value. Regulated prior to transcription.

〔Example〕

First, an overview of a color copying machine as an example of an image forming apparatus to which the present invention is applied will be explained with reference to FIG.

In the figure, reference numeral 1 indicates a transparent original placing table on which an original is placed, and during copying, the original is placed on this original placing table at a predetermined reference position.

A scanning optical system is disposed below the document mounting table 1 and facing the document mounting table.

The scanning optical system includes a light source 3, a first mirror 4, a second mirror 5,
It is composed of a third mirror 6, an imaging lens 7, a fourth mirror 8, a color separation filter 9, and the like.

Among the above, the first units 1 to 9 are formed by the light source 3 and the first mirror,
The second mirror 5 and the third mirror 6 constitute a second unit 10, and during scanning, each unit is moved in the direction of the arrow in conjunction with the same driving source at different speeds from the illustrated home position.

The reflected light image of the original document that receives the light from the light source 3 passes through each mirror, the imaging lens 7, and the color separation filter 19, and then reaches the photosensitive drum 1.
The image is formed on 1. The color separation filter 9 has red (R), green (G), and blue (13
), the reflected light image is reflected on the photoreceptor drum 11.
The colors have been separated by the time it reaches .

The photosensitive drum 11 is charged in advance by a charger 12 in the dark.
・Since it is charged in the same way, an electrostatic latent image of the document image is carried by the irradiation of the reflected light image during rotation. This electrostatic latent image moves with the rotation of the photoreceptor drum 11, and is transferred to black, yellow, magenta, and cyan color toner developing devices 13B and 13Y, which are developing means.

Pass through sections 13M and 13C. During this passage, the toner is first visualized in black, and the next time it is visualized with toner of a color complementary to the color separation filter used to form the electrostatic latent image.

- On the other hand, a transfer drum 18 is disposed close to and opposite to the photoreceptor drum 11, and a transfer portion 26 is disposed in this close opposite portion.
In this transfer section, the opposing surfaces of each drum are rotated so as to move in the same direction at the same circumferential speed in principle.

Then, the transfer sheets 2 stacked on the paper feed section 14 or 15 are separated one by one, and sent out via the conveyance means 16 to the registration rollers 17 and are on standby.

When the leading edge of the 1-toner image on the photosensitive drum 11 reaches the transfer section 26, the vicinity of the leading edge of the transfer paper also reaches the transfer section 26.
6, the transfer paper is fed out from the registration roller 17 at the timing '6' and is gripped by a sheet gripper 24 (see FIG. 4) provided on the circumferential surface of the transfer drum 18, and held as the drum rotates.

The toner image is transferred to this transfer paper by the function of the transfer charger 19 in the transfer section 26, and in the same process, the colors of yellow, magenta, and cyan are superimposed and transferred in that order to form a color image. releases the transfer paper, and the released transfer paper is sequentially separated by a separation charger 25 and a separation claw 20 and sent to a fixing device 22 via a conveyor belt 21, and after being fixed, is discharged onto a tray 23.

Note that residual toner on the photoreceptor drum 11 after transfer is removed by a cleaning device and prepared for the next latent image formation.

In this color copying machine, a photosensitive drum 11, a transfer drum 1
8. The drive motors for the scanning optical system are each provided as an independent drive source, and therefore it is necessary to adjust and control their mutual operation timing.

Of these, the photosensitive drum 11 and the transfer drum 18 are basically controlled so that their opposing peripheral surfaces move in the same direction and at the same speed, and the movement of the scanning optical system is synchronized with this.

Based on such control, control for compensating for the deviation between the theoretical value and the actual value is performed by increasing/decelerating control of the transfer drum.

As a means for this control, a first sensor sik is placed on a stationary member near the transfer section 26 and facing the circumferential surface of the transfer drum 18. The object to be detected by this first sensor S1 is the mark indicated by the symbol M in FIG.
It is marked on the surface of the gripper 24.

Also, on the forward movement path of the first unit 9, a second sensor S2 is located corresponding to the left end of the document placement table 1, that is, the leading edge position of the document.
is placed on the stationary member.

(1) Control in standard mode Under the standard mode in which no binding margin correction is performed, the following control is performed.

In FIG. 5, after the main power of the color copying machine is turned on, when the copy start button is turned on at time TO, the rotation of the transfer drum 18 is started at the same time as the copy star 1' signal rises. . Then, a clock run 1- starts from time To, there is an output from the first sensor S1 at a predetermined time, and a time later from this output time T
1, the first unit 1-9 and the second unit 1O are at the standby stop position before the start of scanning, that is, the third unit is at the home position.
Start from the leftmost position shown in the figure.

Then, the first unit 9 passes the second sensor S2 at time T3, and at this time there is an output from the sensor S2.

Here, the time ta from the time when the first sensor S1 is output to the time when the second sensor S2 is output is set to define the relationship between the scanning optical system and the transfer drum (photosensitive drum). is the actual time corresponding to the theoretical value,
A slight deviation occurs from the same time tc until the output time T2 of the second sensor S2, which is theoretically obtained from calculation.

This deviation time is calculated as Δt, and to compensate for this, control is performed to accelerate (decelerate) the speed of the transfer drum 18 at an arbitrary time T4 before the next first sensor S outputs an output.

The above relationship will be supplementarily explained with reference to FIG.

As shown in FIGS. 6(a) and 6(b), a virtual scale is assumed along the circumferential surface of the transfer drum +8, and the position of the mark M on the virtual scale at time T:I is X. , if the position of the mark M on the virtual scale at time T2 on the power division is Xl, then the position at time T4 is set so that the difference in readings Δ2 (2X KX o ) on this virtual scale becomes 0.
Compensation control is performed to increase the speed of the transfer drum 18.

(2) Binding Margin Correction Control in Correction Mode First, consider the case where binding margin adjustment is performed to obtain a copy having a binding margin of deviation amount Xi, as shown in FIG.

In FIG. 8, the horizontal axis indicates the spatial position of the scanning optical system, that is, the first unit 9, and the home position in the standard mode without binding margin correction is denoted by T P 1 , and the position changed when binding margin correction is performed. Home position
P2 and the exposure scan start position are indicated by the symbol SCN. -・On the other hand, the vertical axis indicates the time axis.

g Under the t<t= mode, the first unit 9 remains at the home position IIPI until time T, as shown by the broken line, and begins to move as time T1 passes, and moves to time T3.
Exposure scanning actually starts at 9. The deviation from the theoretical value of this exposure scanning start time T3 is caused by the transfer driver 1 as described above.
118 at time T4 (see FIG. 5).

On the other hand, under the binding margin correction mode, as shown by the solid line in FIG. The home position IIP2 is moved to a position that is a deviation amount Xi from the home position>IIP1 in the standard mode, and therefore the scanning start point is the scanning start point in the standard mode. Therefore, the image m+ position on the transfer paper is the milk amount. If the paper is shifted by the amount X, a binding margin of the shift amount Xi as shown in FIG. 7 should be obtained.

In this case as well, compensation control is required to match the actual value at the output point of the second sensor S2, which is closer to the knee than the first sensor S1 output point, to the theoretical value, and the speed of the transfer drum 18 is adjusted at the time point T4. This compensation control is performed by adjusting. The above is an explanation at the same size, and the breasts change f.
For example, at the time of reduction, the home position which is further offset by X1 from the home position O P 2 as shown by the dot-dashed line in Fig. 8 is stopped at P 3 and the scanning optical system is It is only necessary to start [·] at the start time T1 (-).

(3) Registration adjustment control in standard mode Next, registration adjustment will be explained.

In FIG. 9, the scanning optical system, that is, the first
Assume that the home position of G L (Pc is actually assembled at the stop position 11 Pa, and there is a positional deviation of X1 between the two. In this case, the so-called Regis 1 to error occurs, and assuming that other conditions are normal, an image shift of the shift amount X1 occurs on the copy.

In other words, if the home position of the first unit 9 is the same as before, the first unit 9 starts moving from time T1 as shown by the broken line, reaches the exposure scanning position SCN, starts exposure scanning at time T3, and the image shift occurs. However, in this example, the home position is shifted by Xi degrees, so the first unit 9 starts from the home position HPa at time T1, as shown by the two-dot chain line, and returns to the original exposure of the unit. Exposure scanning is performed at an early stage, and as a result, the image on the copy is formed at an advanced position.

In this case, as shown by the solid line in FIG. 9, the control to indicate the starting point of the first unit 9 is followed, so that no deviation of the image position occurs on the copy. In this example as well, compensation control is required to match the actual value at the output of the second sensor S2, which is open from the output of the first sensor S1, to the theoretical value, and the time T4 (
This compensation control is performed by adjusting the speed of the transfer drum 18 (see FIG. 5).

The above explanation is for the case of the same magnification, but when the magnification is changed, the correction by the offset X1 is sufficient as shown by the dashed line in FIG.

(4) Control system As shown in FIG. 2, the photoconductor drum motor Mll is connected to the photoconductor drum 11, the transfer drum motor M18 is connected to the transfer drum 18, and the scanning optical system motor M9 is connected to the drive pulley P of the first unit 9. are connected to each other.

The encoder output of each of these motors is input to a motor control section 30 and a motor drive section 31, and each motor constitutes a feedback control circuit driven by the motor drive section 31 via the motor control section 30. ing.

The motor control unit 30 is capable of exchanging information with a central processing unit (hereinafter referred to as CPU) 32 as a means for calculating the correction value Δt, and includes a calculation unit 321, a data storage unit 322,
It is composed of ROM 333 and the like.

The CPU 32 includes a first sensor S2. Each output from the second yancer Sz and the correction data input section 33 is inputted.

The correction data input section 33 is an instruction means for instructing an arbitrary movement date of the toner image formed on the transfer paper, and for example, a ten key on the operation panel is also used, and the deviation amount X1 is inputted.

In the figure, the symbol G indicates a manuscript.

(5) Control process In FIG. 1, in step (2), it is determined whether there is an instruction to move the image. If there is no instruction input, the process proceeds to step (3) and the stop position of the scanning optical system is not changed.

Then, the value of time t in Fig. 5 is the time t (
s). Further, the position XK of the mark M on the virtual scale when the second sensor S2 is output is set to XKo. In this case, the deviation amount X1=0 and no image deviation occurs on the copy.

If there is an instruction input, the process advances to step (1), and the stop position of the scanning optical system is set to the original home position HP based on the input of the deviation fJ
I or t(Pc is moved in advance by nXi. n is a constant determined according to the magnification ratio.

The former corresponds to binding margin correction, and the latter corresponds to registration correction. Then, the value of time t explained in FIG. 5 is set to time 1 (s) in the standard mode.

In this way, although the time t is constant and only the home position of the scanning optical system is adjusted, the 1 to ner images should be moved by that amount on the transfer paper.

Step (So, when copy start is determined, the copy operation starts in step ■, and in step ■, it is determined whether or not time t (the time set in step ■ + Cj) has elapsed since the output of the first sensor S. The first unit 9 is started at step (2) when the time has elapsed.

In step 1, it is determined whether or not there is an output from the second section S2, and at the end of the process, the time point T3 is read into the CPU 32, and the process proceeds to the next step.

In step Φ′, the steps ■, ■ that have already been input
The correction value Δt of the transfer drum 18 is calculated from the difference between the value at time T2, which is calculated based on the input value of , and the time T3, which is calculated by 1υ in step ■.
When time T4) arrives, the speed adjustment of the transfer drum is executed in step O.

〔Effect of the invention〕

According to the present invention, the image position on the copy can be easily rolled to control 1 and the desired binding margin can be corrected by simply instructing the arbitrary movement amount of the toner image to be formed on the transfer paper using the instruction means. and registration correction can be performed.

[Brief explanation of the drawing]

FIG. 1 is a flowchart explaining one embodiment of the present invention.
, FIG. 2 is a block diagram of the same, FIG. 3 is a configuration diagram of the same color copying machine, FIG. 4 is a perspective view of the transfer drum of the same color copying machine, FIG. 5 is a timing chart 1-1, and FIG. Figure 7 is a diagram explaining the rotational position of the transfer drum, Figure 7 is a diagram explaining the amount of image shift on a copy using an example of binding margin, and Figures 8 and 9 are diagrams showing the relationship between the position and time of the scanning optical system. FIG. 9...First unit, 33...Correction data input section, M...Mark.

Claims (1)

[Scope of Claims] A transparent document placing table on which a document is placed, a scanning optical system arranged opposite to the document placing table and scanning the document on the document placing table, and a scanning optical system that scans the document on the document placing table; A photoreceptor that carries an electrostatic latent image while being irradiated with a reflected light image from a document on a mounting table, a developing means that visualizes the electrostatic latent image on the photoreceptor into a toner image, and this photoreceptor. is placed opposite to
and a transfer paper holder to which the transfer paper can be attached and detached; a driving means for independently driving the scanning optical system, the photoreceptor, and the transfer paper holder; In an image forming apparatus that creates a copy of a document by overlappingly transferring a toner image on the photoconductor to a transfer paper on the transfer paper holder as the photoreceptor is operated a plurality of times, a first detecting mark on the transfer paper holder is provided. A sensor S_1 and a second sensor S_ disposed on the forward movement path of the scanning optical system.
2, and the mark detection time point T_2 by the first sensor S_1
a correction value calculation means for calculating the deviation between the theoretical value and the actual value of the time from the time to the detection time T_3 during forward movement of the scanning optical system by the second sensor S_2 as a correction value Δt; and toner to be formed on the transfer paper. It has an instruction means for instructing an arbitrary amount of movement of the image, and when the instruction means instructs the amount of movement, based on the instruction, the standby stop position of the scanning optical system before the start of scanning is changed. The above correction value Δt according to this change is
An image forming apparatus characterized in that the next time the toner image and the transfer paper are aligned by determining the correction value Δt and adjusting the speed of the transfer paper holder to compensate for this correction value Δt.