JPH0336559A - digital image forming device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a digital image forming apparatus such as a copying machine, a facsimile machine, and a printer, and particularly to a digital image forming apparatus characterized by image alignment.

[Conventional technology]

Various techniques have been proposed regarding image registration (registration) for aligning the positions of the transfer paper and the image on the photoreceptor.

For example, Japanese Patent Application Laid-Open No. 120369/1983 proposes a technique in which a transfer sheet passes through a registration roller to perform registration, and when it reaches a paper sensor, it is temporarily stopped and then conveyed again at a certain timing.

Furthermore, Japanese Patent Laid-Open No. 62-255357 proposes a technique for controlling the timing so that each paper feed section hits the registration roller at the same time in a copying machine equipped with a plurality of paper feed sections. There is.

In addition, many copying machines generally use a method in which the leading edge of a transfer sheet is brought into contact with a stopped registration roller, the registration rollers are rotated at appropriate timing, and the transfer sheet is conveyed to a transfer device.

[Problem to be solved by the invention]

The above-mentioned conventional technology has a problem in that as the copying speed of the copying machine increases, the variation in response delay of the electromagnetic clutch that drives the registration rollers increases, making it impossible to perform accurate registration.

In addition, with paper feeding devices that feed roll paper and cut it to a predetermined length, it is difficult to stop the roll paper midway once it has been fed due to inertia. The feeding of the paper must be continued until it is cut, and it is necessary to loosen the transfer paper midway (before the registration rollers) and provide a buffer.

In this case as well, there is a problem in that when the transfer paper becomes long, skew occurs and the wrinkled two images become skewed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a digital image forming apparatus that eliminates the drawbacks of the prior art described above and allows accurate image positioning.

[Means to solve the problem]

The above object includes an image reading means for converting a document image into a digital image signal, a storage means for storing the digital image signal, a photoreceptor, a latent image forming means for forming a latent image on the photoreceptor, and a latent image forming means for forming a latent image on the photoreceptor. A developing means to visualize the image, a transfer means to transfer the developed image to the transfer paper, a paper feeding means to feed the transfer paper, a conveyance means to convey the transfer paper from the paper feed means to the transfer means, and a conveyance means for conveying the transfer paper from the paper supply means to the transfer means. This is achieved by including a transfer sheet detection means installed in the path, and a control means for performing control such as reading the image signal from the storage means and forming a latent image based on the detection means signal.

[Effect]

Registration is performed by writing document information into an image storage device without temporarily stopping either the document or the transfer paper, and then reading it out at a certain timing to form a latent image on the photoreceptor.

〔Example〕

An outline of a copying machine to which an embodiment of the present invention is applied will be explained with reference to FIG. This copying machine includes a reading device xi o o as a reading means for reading an original, and an image information storage device 300 as a storage means for storing information on the read original. A copying circuit 500 that executes a series of processes for copying stored information onto paper; a system control device 3o2 that controls the copying circuit 500; The system controller 302 includes an operating device 400 as an operating means for performing key manual input to the system control device 302 . Note that the operating device 400 includes a display device that displays various information.

The operating device 400 includes an operating panel 402 and an operating control circuit 4.
Consists of 01. A plane view of the operation panel 402 is shown in FIG. The operation panel 402 includes keys (mode clear, stop, start 2) that specify the functions shown in FIG.
Numeric keypad, ? Adjusted once.

Image quality adjustment, paper size, enlargement, reduction memory number.

(Settings) Character display (number of sheets set, number of copies, variable magnification), document insertion possible indication, and document insertion direction indication.

An overview of the mechanical configuration of the reading device 100 is shown in FIG. When the operator inserts the document into roller 1, the document is
The contact glass 2 is conveyed in the sub-scanning direction between the contact glass 2 and the reflection plate 3 in accordance with the rotation of the contact glass 2 .

During this transportation, the surface of the document is scanned in the main scanning direction by light from the fluorescent lamp 4. The reflected light is imaged on an imaging device (CCD) 6 via a lens 5, and document information is read. C
The original image formed on the CDB is output as an analog signal in synchronization with a clock generated from a write synchronization control circuit 105, and is amplified by an image amplification circuit 101. A/D
The conversion circuit 102 converts the amplified analog image signal into multivalued digital image information representing each pixel. The shading correction circuit 103 corrects noise, light intensity unevenness, etc. in the original image.
Distortion of digital image information due to dirt on the contact glass 2, uneven sensitivity of the CCD 6, etc. is corrected. Thereafter, the image processing circuit 104 converts it into digital recorded image information. Digitally recorded image information is output to the image storage device 300,
The data is written into one page memory of the image memory unit 301.

The digitally recorded image information stored in the page memory is converted into laser light in the next copying circuit 500.

FIG. 2 shows the image information storage device 300. Copying circuit 50
Copying device 200 incorporating 0 and operating device 400
An overview of the mechanical configuration is shown below.

Digitally recorded image information read from the page memory is received by a line driver circuit 501 and amplified by a laser driver circuit 502. Digitally recorded image information is 1
This is a binary signal of 1 bit (recording/non-recording) per pixel, and the laser driver circuit 502 activates the laser diode 503 to emit light in response to the binary signal. The laser light emitted by the laser diode 503 is reflected by the rotating polygon mirror 11, passes through the polygon mirror surface tilt correction cylindrical lens 12, passes through the f-theta lens 13, and is transmitted to the first S-sea 14.
The light is reflected by the second reflector 15 and the third reflector 16 and is irradiated onto the photosensitive drum 17 to form an image.

The rotating polygon mirror 11 is fixed to a polygon drive motor 18 and a rotating shaft 19, and the motor 18 rotates at a constant speed, thereby driving the polygon mirror 11 to rotate at a constant speed. As the polygon mirror 11 rotates, the laser beam described above is scanned in a direction perpendicular to the rotation direction of the photoreceptor drum 17, that is, in a direction along the drum axis.

The surface of the photosensitive drum 17 is uniformly charged by a charger connected to a negative high voltage generator. When the laser beam emitted based on the digitally recorded image information is irradiated onto the uniformly charged surface of the photoreceptor, the electric charge on the surface of the photoreceptor flows to the equipment ground of the drum 17 body and disappears due to the photoconductive phenomenon. . Here, the laser is not turned on in areas where the original density is low (the binary signal is at a non-recording level), and the laser is turned on in areas where the original density is high (the binary signal is at the recording level). As a result, the portion of the surface of the photoreceptor drum that corresponds to the light density portion of the original has a potential of 1750 cm, and the portion that corresponds to the high density portion of the original has a potential of approximately 11 oov.
An electrostatic latent image is formed corresponding to the density of the original. This electrostatic latent image is developed by the developing unit 20 to form a toner image on the surface of the photoreceptor drum 17. Note that the toner in the developing unit 20 is negatively charged by stirring, the developing unit 20 is biased to about -550 V by a developing bias generator, and the toner adheres to a place where the surface potential of the photoreceptor drum 17 is higher than the developing bias. Toner and an image corresponding to the original image are formed.

On the other hand, the recording paper is selected from one of the three paper feed trays 21, fed by the feed operation of the feed roller 22, cut into an appropriate size by the cutter 23, and then
The registration roller 24 passes under the photosensitive drum F with a predetermined tie, and during this time the toner image is transferred onto the recording paper by the action of the transfer charger 25. The transferred recording paper is then sent to a thermal fixing unit 26, where the toner is fixed to the recording paper, and the recording paper is discharged to a paper output tray 27.

Referring again to FIG. The copying machine of this embodiment includes an image information storage device 30 in addition to a reading device 100 and a copying circuit 500.
0, and this storage device 300 consists of an image memory section 301 and a system control device 302. In this embodiment, the image memory section 301, the system control device 302, and the operating device 400 are the copying machine 2 shown in FIG.
It is housed in a 00 housing. Reading device 100
．． The copying circuit 5002, the image information storage device 300, and the operating device 400 are connected to the R3422 standard signal line Ll.

L2. and L3, and serial data transmission is performed between the two at a transmission rate of 9600 bps.

FIG. 5 is a partially enlarged view of the copying device (recording device),
17 is a photosensitive drum, 30 is an electrostatic latent image forming section, 25 is a transfer/separation charger, 24, 31° 32 is a pair of transport rollers, 33 is a transfer paper sensor for registration when feeding roll paper, 34 is a roll 22. 35 is a pair of feed rollers for roll feeding; 23 is a rotary cutter that cuts the running transfer paper without stopping; 36 is the type of roll paper set [(f , second original drawing paper, etc.), 21 is a roll paper, 37 is a sensor that detects when the roll paper is empty, 38, 39 is a sensor for registration during manual paper feeding, 40 .41
is a pair of feeders for manual paper feeding.

FIG. 6 is a control circuit diagram of a copying device (recording device),
In FIG. 3, it corresponds to write drive control circuit 504. 601 is a microprocessor, 602 is a clock signal generator, 603 is a read/write memory (RAM), 604
is a read-only memory (ROM), 605 is a serial communication controller, 606 is a timer, 607 is an interrupt controller, and 608 and 609 are human output controllers.

To further explain FIGS. 5 and 6, when a signal indicating that a document has been inserted is sent from the reading device 100 to the system control device 302, the system control device 302 instructs the recording device to start feeding paper. Upon receiving this command, the CPU 6 of the recording device
01 activates the paper feed motor of the paper feed tray (in this case, the upper stage) designated (by the operation unit) to start feeding paper.

When the leading edge of the transfer paper reaches the transfer paper sensor 33, the CPU
601 starts the timer 106. The timer time is determined by reading the setting conditions (0 to 15) of the digital switch 610 also connected to the I10 boat, and when the set time is reached, a read signal is output to the memory.

FIG. 7 is a control circuit diagram of a copying device (recording device) according to another example, and only the differences from FIG. 6 will be explained.
611 is a conveyance control circuit, and 612 is a conveyance motor with an encoder.

FIG. 8 is a control flowchart, and to explain the operation, when a signal indicating that a document is inserted is sent from the reading device 100 to the system control device 302 (8-1)
, the system control device 302 instructs the recording device to start recording (8-2). Upon receiving this signal, the CPU 6 of the recording device
01 starts the paper feed motor of the specified paper feed table (by the operation unit) to start paper feeding, and also starts the conveyance motor 612.
(8-3). When the leading edge of the transfer paper reaches the transfer paper sensor (registration sensor) 33, a signal is generated (8-4) and input manually to the I10 port. Thereby, the CPU 601 initializes the counter and starts counting the encoder pulses of the transport motor 612 (8
-5.8-6).

The setting values are the same! It is determined by reading the position (0 to 15) of the digital switch 610 for fine adjustment connected to the 10 boat (8-7), and when that number of pulses is reached (8-1
0,8-11) Output a readout signal to the memory.8-12.8-13) Form a latent image and align the image.

FIG. 9 is a circuit diagram of a copying apparatus (recording apparatus) according to yet another example, and only the differences from FIG. 7 will be described. Reference numeral 612 is a stepping motor as a transport motor.

FIG. 10 is a control flowchart, and its operation will be explained as follows: When a signal indicating that a document has been inserted is sent from the reading device 100 to the system control device 302 (10-
1) The system control device 302 instructs the recording device to start recording (10-2) Upon receiving this signal, the system control device 302 instructs the recording device to start recording.
U601 activates the paper feed motor of the paper feed tray specified as j (by the operation unit) to start feeding the paper, and also starts outputting pulses for driving the transport motor (10-3). The leading edge of the transfer paper is the transfer paper sensor (registration sensor) 3
3, a signal is generated and input to the 10-4) I10 port. Thereby, the CPU 601 initializes the counter and starts counting the encoder pulses of the stepping motor 612 (10-5.1O-6). The set value is determined by reading the position (O ~ 15) of the digital switch 610 for fine adjustment connected to the same <I10 port (10-7), and when that number of pulses is reached (10-1
0,1O-11), outputs a read signal to the memory 10-12.1O-13), forms a latent image, and aligns the image.

〔Effect of the invention〕

As explained above, according to the present invention, the original is read once and stored in the memory, and the transfer paper is not stopped once in the middle, so registration variations during repeat copying can be reduced, and conveyance Accordingly, it is possible to provide a digimole image arresting device that can perform image positioning while reducing troubles such as paper jams.

[Brief explanation of drawings]

1 and 2 are schematic configuration diagrams of a mechanical section of an embodiment of a digital copying machine according to the present invention, FIG. 3 is a block diagram showing an outline of the configuration of electrical elements of the embodiment, and FIG. 3
5 is a partially enlarged view of the copying device, FIG. 6 is a control circuit diagram of the copying device, FIG. 7 is a control circuit diagram of another example of the copying device, and FIG. Is the diagram based on Figure 7? FIG. 9 is a control circuit diagram of a copying apparatus according to still another example, and FIG. 10 is a flowchart of operation in the control circuit of FIG. 9. 1...Roller, 2...Contact glass, 3...
Reflector, 4...Fluorescent lamp, 5...Lens, 6...C
CD, 11... Rotating polygon mirror, 12... Cylindrical lens, 13... f-theta lens, 14... First mirror 15... Second ξ mirror 16... Third mirror
17... Photosensitive drum, 18... Motor, 19...
- Rotating shaft, 20... Developing unit, 21... Paper feed tray, 22... Feeding roller, 23... Cutter, 24... Registration roller, 25... Transfer charger, 25... ...Transfer/separation charger (transfer means), 26
...Thermal fixing unit, 27... Paper output tray, 30.
... Electrostatic latent image forming section (electrostatic latent image forming means), 33...
Transfer paper sensor (transfer paper detection means), 100...reading device (N image reading means), 200...copying device (copying means), 300...image information storage device, 301...image memory Part (storage means), 302...System III
control device (control means), 400...operation device f (operation display means), 601...CPU (control means) Fig. 5PJ2 Fig. 5 Fig. 1O Fig.

Claims (3)

[Claims] (1) An image reading means for converting a document image into a digital image signal, a storage means for storing the digital image signal, a photoreceptor, a latent image forming means for forming a latent image on the photoreceptor, and a latent image forming means for displaying the latent image. A developing means for forming an image, a transfer means for transferring the developed image onto a transfer paper, a paper feeding means for feeding the transfer paper, a conveying means for conveying the transfer paper from the paper feeding means to the transfer means, and a path for the conveying means. What is claimed is: 1. A digital image forming apparatus comprising: a transfer sheet detecting means installed therein; and a control means for reading out an image signal from a storage means and controlling the formation of a latent image based on a signal from the detecting means. (2) The digital image forming apparatus according to claim (1), wherein the distance between the transfer sheet detection means and the transfer means is set longer than the distance between the latent image forming means and the transfer means. (3) an image reading means for converting a document image into a digital image signal, a storage means for storing the digital image signal, a photoreceptor, a latent image forming means for forming a latent image on the photoreceptor, and a latent image forming means for displaying the latent image. A developing means for forming an image, a transfer means for transferring the developed image onto transfer paper, a paper feeding means for feeding the transfer paper, a conveying means for conveying the transfer paper from the paper feeding means to the transfer means, and a driving means for driving the conveying means. a driving device for a conveying means, a pulse generating device that generates a pulse signal proportional to the rotation of the driving device, and a counting device that counts the pulse signal generated from the pulse generating device; A digital image forming apparatus characterized in that a latent image is formed by controlling start/stop of reading out image signals in the storage means based on the above-mentioned storage means.