JPH01198768A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent image drift due to the misregistration of an original by controlling an image forming means according to deviation detected by a detecting means. CONSTITUTION:When an inlet sensor 3 or 22 detects an original and copying instructions are started, an inlet stopper solenoid 21 or 29 is turned on, and a DF motor 19 normally rotates to convey the original. Monitoring continues until the original arrives at a DF outlet sensor 13. When the original arrives at the DF outlet sensor 13, the DF motor 19 is turned off to start the reverse rotation of the DF motor 19, and clocks from a sensor 20 are counted after the original passes by the DF outlet sensor 13. When the counted value of the clocks reaches S, the DF motor 19 is turned off, a break is made to control in the way that the entire belt 7 of the DF motor is completely stopped. Moreover, clocks from the sensor 20 are counted simultaneously after the DF motor 19 is turned off. Namely, clocks are counted in order to absorb the shift of the stop position due to the variance of machine's inertia and changes with elapsed time. Thus, images can be registered correctly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus equipped with a document handling device for feeding a document to a predetermined position.

[Prior Art] In recent years, image forming apparatuses such as copying machines have been equipped with a document handling device that feeds the document to a predetermined position, such as an exposure position, in order to reduce the burden of manipulating the document by the operator. are increasing.

By the way, when a document is fed and stopped at a predetermined position, the accuracy of the stopping position is very important. In other words, if the stop position deviates from a certain predetermined position, the latent image on the recording medium that forms the electrostatic latent image will also shift by that amount,
This is because as a result, the image on the recording paper also becomes blurred.

Therefore, in the past, as a method for stopping a document at a predetermined position, (a) a stopper that can be freely extended and retracted is provided at a predetermined position, and the document is stopped by hitting this stopper.

(b) An encoder is attached to the document feed motor, and the pulses of the encoder are counted from a predetermined preparation position for detecting the document, and when a certain predetermined number of pulses is counted, the feed motor is braked to a stop.

etc.

[Problems to be Solved by the Invention] However, the method (a) above is mechanically complex and expensive, and also has the problem of buckling for very thin originals, making it difficult to operate at high speeds. It also had the disadvantage of facing the opposite direction.

Regarding method (b), there are methods such as applying braking by electrically connecting both ends of the document feed motor, adding an electromagnetic brake to the motor drive system, or a combination of the above, but Due to variations, changes over time, inertia, etc., errors in the stopping position cannot be avoided. Moreover, in order to reduce these effects as much as possible, it is possible to reduce the feeding speed before applying the brake, but this has the disadvantage that the document exchange speed decreases.

SUMMARY OF THE INVENTION In view of the above points, an object of the present invention is to provide an improved image forming apparatus.

A further object of the present invention is to provide an image forming apparatus that can prevent image displacement caused by positional displacement of a document.

A further object of the present invention is to provide an image forming apparatus that does not cause image shift when forming an image using a document handling device.

A further object of the present invention is to provide an image forming apparatus that can accurately register and ration images without reducing document feeding speed.

A further object of the present invention is to provide an image forming apparatus that can perform accurate image registration without adding any complicated mechanism.

A further object of the present invention is to provide an image forming apparatus with high reliability and productivity.

[Means for Solving the Problems] In order to achieve the object, an image forming apparatus according to the present invention includes a document feeding device that feeds a document to a predetermined position, and a document feeding device that feeds a document to a predetermined position. a detection means for detecting the amount of deviation between the stop position and the predetermined position; an image forming means for forming the original image on the recording material; and a detection means for controlling the position of the image formed on the recording material. and a control means for controlling the image forming means according to the amount of deviation caused.

Further, the image forming apparatus according to the invention includes a specifying means for specifying a desired area of a document, a placing means for placing the document, and an image of the document placed on the placing means is specified by the specifying means. an image forming means for copying onto a recording material according to the area set by the recording material; a detection means for detecting the amount of deviation of the document placed on the placement means from a reference position; and a detection means for controlling the position of the image formed on the recording material. and control means for controlling the image forming means in accordance with the amount of deviation detected by the detecting means.

Further, the image forming apparatus according to the present invention includes a specifying means for specifying a desired area of a document, a placing means for placing the document, and a document image placed on the placing means. an image forming means for copying onto a recording material according to the area set on the recording material; a detection means for detecting the amount of deviation of the document placed on the placement means from a reference position; and a detection means for controlling the position of the image formed on the recording material. The image forming apparatus includes a control means for controlling the image forming means according to the amount of deviation detected by the detecting means, and an original feeding means for feeding the original to a reference position of the placing means.

[Function] According to the present invention, the detection means detects the amount of error in the stopping position of the original relative to a certain predetermined position when the original is fed and stopped, and forms an image according to the amount of error. Controls the timing of conveyance of recording paper.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a copying device (original handling device) according to the present invention.
FIG. 2 is a schematic diagram showing an example of the DF (hereinafter referred to as DF). In the figure, reference numeral 1 denotes a tray for stacking sheet originals, and the sheet originals 2 are placed on the tray 1 with the lower side in the figure facing up.

The first document detection DF sensor is a reflective sensor that detects the leading and trailing edges of the 3-sheet document, and the feed roller 4.5
are in pressure contact with each other to sandwich and transport the sheet original.

A stopper 6 prevents the document from being fed onto the document table glass (platen glass) 10, and is released by the operation of the DF lost flange solenoid 21 to allow the document to be fed.

The full-surface belt 7 is an endless belt with a width large enough to cover the entire surface of the sheet original, and the surface has a sufficient coefficient of friction to allow the original to slide and be conveyed on the original platen glass lO using frictional force. The belt is wrapped around a drive roller 8 and a turn roller 9, and is configured to prevent the entire belt 7 and drive roller 8 from slipping.

Furthermore, the ejection flapper 30 guides the original ejected from the original platen glass IO. DF output sensor 1 for document detection
Reference numeral 3 denotes a reflective sensor, and when the leading edge of the document is detected by this sensor, the entire belt is first stopped and then run in the reverse direction, and when the INF output roller sensor 13 detects the trailing edge of the document, it is stopped at a predetermined position.

On the other hand, a well-known digitizer 26 is mounted on the top of the DF of the present invention, and a digitizer cover 27 that covers the entire surface of the digitizer is placed on top of the digitizer 26. Further, there is a digitizer paper feed port at the upper left of the [IF] for feeding the original on the digitizer, and although it is hidden when the cover is closed, it is exposed when the cover is open.

This digitizer paper feed port has a digitizer population detection sensor 22 that detects documents stacked on the digitizer surface.
A reflective sensor is used. and feed roller 23
．． 24 press against each other to sandwich and convey the sheet original.

A stopper 25 prevents the document from being fed from the digitizer paper feed port onto the platen glass, and is released by the operation of the digitizer stopper solenoid 29, allowing the document to be fed onto the platen glass.

The document sent out from the digitizer paper feed port by the conveyance rollers 23 and 24 is sent along the guide plate and is sent onto the platen glass O from the right end of the above-mentioned full-surface belt 7.

All the rollers and belts are driven by a motor 19, and are provided with a clock disk and a sensor 20 that generate clock pulses when they rotate, and the operation of the DF is controlled by this clock.

After the exposure operation is completed, the originals sent out by the full-surface belt 7 are reversed by the paper ejection flapper 30, ejected by the paper ejection rollers 15.1B pressed against each other, and sequentially stacked on the digitizer cover described above.

Next, in the main body 100, 103 is an illumination lamp (exposure lamp) that illuminates the original, 105, 107, and 109 are scanning reflecting mirrors (scanning mirrors) that change the optical path of the reflected light from the original, and 111 is a focusing and changing lamp. 113 is a fourth reflecting mirror (scanning mirror) that changes the optical path. 115 is an optical system motor for driving the optical system, and 117 and 121 are sensors for detecting the optical system.

131 is a photosensitive drum, 133 is a main motor that drives the photosensitive drum 131, 135 is a high voltage unit, 137 is a blank exposure unit, 139 is a developer, 140 is a developing roller, 141 is a transfer charger, 143 is a separation charger, and 145 is a cleaning device.

Also, 151 is an upper cassette, 153 is a lower cassette, 1
55 and 157 are paper feed rollers, and 159 is a registration roller. Further, 161 is a conveyor belt that conveys the recording paper on which an image has been recorded to the fixing side, and 163 is a fixed device that fixes the conveyed recording paper by thermocompression bonding.

The surface of the above-mentioned photosensitive drum 131 is made of a seamless photosensitive member using a photoconductor and an electric conductor. The activated main motor 133 starts rotating in the direction of the arrow in this figure. Next, when the predetermined rotation control and potential control processing (preprocessing) of the drum 131 is completed,
The original placed on the original platen glass IO is illuminated by an illumination lamp 103 that is integrated with a first scanning mirror 105, and the reflected light from the original is transmitted to the first scanning mirror 105, the second scanning mirror 107, and the third scanning mirror 105. Scanning mirror 109, lens I
ll, and the drum 13 via the fourth scanning mirror 113
The image is formed on 1.

The drum 131 is corona charged by a high pressure unit 135. After that, the image illuminated by the illumination lamp 103 (
The original image) is exposed to slit light, and an electrostatic latent image is formed on the drum 131 using a known electrophotographic method. Next, the electrostatic latent image on the photosensitive drum 131 is developed by the developing roller 140 of the developing device 139 and visualized as a toner image. transferred on top.

That is, the upper cassette 151 or the lower cassette 1
The transfer paper in 53 is fed into the main unit by a paper feed roller 155 or 157, and is sent toward the photosensitive drum 131 with accurate timing by a registration roller 159, so that the leading edge of the image on the photosensitive drum and the leading edge of the transfer paper are aligned. are matched. Thereafter, the transfer paper passes between the transfer charger 141 and the drum 131, so that the toner image on the drum 131 is transferred onto the transfer paper. After this transfer is completed, the transfer paper is separated from the drum 131 by a separation charger 143, guided to a fixing device 163 by a conveyor belt 161, where the toner image is fixed by pressure and heating, and then the transfer paper is transferred to a discharge roller 165. It is discharged to the outside of the main body 100.

After the transfer, the drum 131 continues to rotate, and its surface is cleaned by a cleaning device 145 composed of a cleaning roller and an elastic blade.

FIG. 2A is a schematic diagram of the digitizer section. This consists of a planar resistor 50 that reads the position in the horizontal direction (X direction) and the vertical direction (Y direction), and a reed vent switch (SW) 5.
1. The planar resistor 50 is located not only under the sheet where the original is placed, but also under keys such as the clear key 52, the registration key 53, and the continuous designation key 54, and is set by the Ben SW as described later. Voltage is output depending on the position and read as the area setting value or the above key.

The operator places the document face up on the resistor 50 and sets it so that it is aligned with the upper right corner. Then, by pressing two points in the area to be specified with the Ben SW 51, for example, points A and A' or points B and B', the area A-B'-A'-B'-A is specified, and the registration key described later is pressed. By pressing 53 with the Ben SW, area designation is set, and, for example, a trimming function or an image conversion function is activated during copying, and a copy as shown in FIG. 2B is output.

When using a document handling device equipped with a digitizer as described above, matching between the recording paper and the image is particularly important, and the present invention is particularly important in such a case.

FIG. 3 is a block diagram showing the control section of the Kino H& example.

In the figure, the controller 200 includes a CPU, ROM, RAM, I
CPII is a well-known microcomputer (hereinafter referred to as a microcomputer) having a ROM, etc., and the CPII is R
AM, access Ilo.

First, the DF unit is connected to the driver 201 to connect each of the above-mentioned loads, that is, the forward rotation and reverse rotation signals of the drive motor, the DF person lost collar, the digitizer inlet stop collar SL, and the brake to 0N1.
A signal that turns 0FF is output. As human signals, signals from the aforementioned sensors, ie, the DF sensor, the digitizer population sensor, and the digitizer population sensor are inputted via the buffer 205. Furthermore, a clock pulse from the sensor 20 is input to the interrupt terminal 1nTl of the controller 200. Further, regarding the digitizer section 300, the output signal is an X/Y application switching signal that switches the voltage applied to the digitizer electrode.

Leadven digitizer 7M, 41Ii as input signal
There is a lead-ben signal that is turned on when the surface is suppressed, and an X-axis input terminal signal and a Y-axis input terminal signal that input analog signals output according to the suppressed position in the X/Y glaze direction, respectively.

Furthermore, the output signals for each control section of the copying machine are as follows:
Through the driver 203, forward/reverse signals for the optical system motor, main motor drive signals, lamp control signals, paper feed roller control signals, registration clutch signals for rotating the registration rollers and controlling the conveyance of recording paper, etc. are output. In addition, input signals include a signal from the optical home position sensor 117, a signal from the image tip sensor 121 that detects the timing of the registration roller, and a certain fixed rotation angle of the main motor. The main body clock pulses, etc. that generate the pulses are manually input.

Next, the operation of the present invention will be explained using timing charts shown in FIGS. 4A to 4C.

When the trailing edge of the document is detected by the DF output sensor 13,
After counting a predetermined number S of clock pulses, the drive of the DF motor 19 is turned off, and at the same time, the brake is applied to stop the document conveyance.

However, due to inertia, load variations, etc., the document does not stop instantaneously after braking is applied, but usually the DF motor 19 rotates for N clock pulses and the document stops.

FIG. 48 shows that there was an increase of approximately M clocks until the document stopped, that is, the document was shifted from the predetermined position by a distance corresponding to M clocks. In FIG. 1, this means that the document has moved back to the right by M clocks.

4B and 4C show the timing of aligning the images on the recording paper in the copying machine, that is, the timing control of registration. This is a timing chart when the DF motor stops, and the 4th C
The figure is a timing chart when M>O.

First, referring to FIG. 4B, when the document feeding and stopping operations are completed, the optical system drive motor is turned on. Then, when the image tip signal is detected by the image tip sensor 121 after passing through the home position sensor 117, the main body clock pulses outputted by the rotation of the main body motor 133 are counted by the number P corresponding to the N clocks. Turn on the resist clutch. As a result, the recording paper is accurately registered with the image on the drum, transferred and fixed, and then ejected from the machine.

Next, referring to FIG. 4C, after the image tip signal is detected, the main body clock is set to the number P10R corresponding to the N+M.
count and turn on the resist clutch. Here, R is a correction by the clock increment M of the DF motor, and it shows that the deviation in the position of the document corresponding to the increment of M clock pulses corresponds to the main motor clock number R on the drum. Both the DF motor clock and the main motor clock are usually 0.2 to 0.8n++ per clock cycle.
Normally, this corresponds to a distance of about n.

Although the case where M>O has been described above, the same problem also applies when M<O, that is, the OF motor clock disappears before reaching N clock pulses. In this case, the count for controlling the resist clutch of the main body is simply set to P-H.

FIG. 5 is a flowchart for carrying out the above control.

The nut layer side will be further explained below based on this flowchart.

When a document is detected by the population sensor 3 or 22 and a copy command is started, the process proceeds to step 1, the population stopper solenoid 21 or 29 is turned on, and the DF motor 19 is turned on.
rotates forward to transport the original, and monitoring continues until the original reaches the DF output sensor 13.

When the document reaches the exit sensor 13, proceed to step 2, turn off the DF motor 19, and then turn the DF motor 19 off.
After the document is removed from the OF output sensor 13, the clock signal from the sensor 20 starts counting.

When the clock count value reaches S, proceed to step 3, turn off the DF motor 19, turn on the brake, and turn on D.
Control is performed to completely stop the entire belt 7 of the F, but the sensor 2 is further turned off after the DF motor 19 is turned off.
Count clocks starting from 0 at the same time. That is, the clock is counted in order to absorb variations in the inertia of the machine and changes in the stopping position due to changes over time.

Next, in step 4, a predetermined standard value (N) is subtracted from the number of clocks (Q) until the clock disappears completely (the result is set as M). Here, M can naturally be a positive or negative integer.

Next, proceed to step 5, and add the main body clock R, which corresponds to the clock M, to the clock number P of the resist clutch ON timing to obtain the actual resist clutch ON signal (when M is positive, R is also positive). , when R is negative, R is also negative).

In the above embodiment, correction control of the registration clutch is performed based on the clock pulse of the main motor of the main body, but it can also be performed using a variable timer created by the CPU in the controller.

Furthermore, the present invention is not limited to the above embodiments,
Various modifications are possible within the scope of the claims.

[Effects of the Invention] As described above, according to the present invention, it is possible to achieve accurate image registration without adding any complicated mechanism, and to provide an image forming apparatus with high reliability and productivity. can do.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of a copying apparatus according to the present invention; FIGS. 28 and 2B are schematic diagrams of a digitizer; FIG. 3 is a block diagram showing a control section of this embodiment; Figure, 4th
FIG. B and FIG. 4C are timing diagrams showing the operation of this embodiment, and FIG. 5 is a flowchart showing the control flow of this embodiment. 1... Population tray, 2... Document, 3... DF person sensor, 4.5... Feed roller, 6... Stopper, 7... Whole surface belt, 8... Drive roller, 9... Turn roller, lO... Platen (original) glass, 13... DF output sensor 1, 15.16... Paper ejection roller, 22... Digitizer population detection sensor, 23.24...
・Feed roller, 25... Stopper, 26... Digitizer, 27... Digitizer cover, 29... Digitizer stop valve solenoid, 30...
...Paper discharge flapper, 131...Photosensitive drum, 139...Developer, 161...Transport belt, 163...Fixer. Figure 2A Figure 28 Two ministers, two ministers, fraud, oo o. Drop immersion

Claims (1)

[Scope of Claims] 1) Original feeding means for feeding the original to a predetermined position; and detection means for detecting the amount of deviation between the stop position of the original fed by the feeding means and the predetermined position; an image forming means for forming an original image on a recording material; and a control means for controlling the image forming means according to the amount of deviation detected by the detection means to control the position of the image formed on the recording material. An image forming apparatus comprising: 2) The document feeding device includes a signal generating device that generates a pulse signal synchronously with document feeding, and the detecting device detects the amount of deviation based on the pulse signal generated from the signal generating device. The image forming apparatus according to claim 1, characterized in that: 3) The image forming apparatus according to claim 1, wherein the control means controls feeding timing of the recording material according to the amount of deviation. 4) The image forming means forms an electrostatic latent image on the photoreceptor, develops it, and then transfers it to the recording material, and the control means aligns the image on the photoreceptor with the recording material. 4. The image forming apparatus according to claim 3, wherein the image forming apparatus controls timing. 5) The image forming means has a signal generating means that generates a pulse signal in synchronization with the rotation of the photoreceptor, and the control means controls the positioning timing based on the pulse signal generated from the signal generating means. 5. The image forming apparatus according to claim 4, wherein the image forming apparatus controls the image forming apparatus. 6) specifying means for specifying a desired area of the original, a placing means for placing the original, and placing the original image placed on the placing means on a recording material according to the area specified by the specifying means; an image forming means for copying; a detecting means for detecting the amount of deviation of the document placed on the placing means from a reference position; an image forming apparatus comprising: a control means for controlling the image forming means according to the amount of deviation caused by the image forming apparatus. 7) specifying means for specifying a desired area of the original, a placing means for placing the original, and placing the original image placed on the placing means on a recording material according to the area specified by the specifying means; an image forming means for copying; a detecting means for detecting the amount of deviation of the document placed on the placing means from a reference position; An image forming apparatus comprising: a control means for controlling the image forming means according to the amount of deviation caused by the image forming means; and an original feeding means for feeding the original to a reference position of the placing means. 8) The document feeding device includes a signal generating device that generates a pulse signal synchronously with document feeding, and the detecting device detects the amount of deviation based on the pulse signal generated from the signal generating device. The image forming apparatus according to claim 7. 9) The image forming apparatus according to claim 6, wherein the control means controls feeding timing of the recording material according to the amount of deviation. 10) The image forming means forms an electrostatic latent image on the photoreceptor, develops it, and then transfers it to the recording material, and the control means controls the timing of positioning the image on the photoreceptor and the recording material. 10. The image forming apparatus according to claim 9, wherein the image forming apparatus controls: 11) The image forming means has a signal generating means that generates a pulse signal in synchronization with the rotation of the photoreceptor, and the control means controls the positioning timing based on the pulse signal generated from the signal generating means. 11. The image forming apparatus according to claim 10, wherein the image forming apparatus controls the image forming apparatus. 12) The image forming apparatus according to claim 7, wherein the designating means is provided above the document feeding means.