JPS6135463A - Electrostatic recording device - Google Patents

Abstract

PURPOSE:To control registration timing properly without reference to the size and loading position of transfer paper and to prevent a deviation in registration by making the registration timing different according to the transfer paper of selected size and a paper feed part where the transfer paper is loaded. CONSTITUTION:Confirmation of each paper size is performed previously by experiment and examination and a corrected value is determined on knowing the absolute value. Then, a delay circuit is used to correct the driving timing of a registration roller 12. When transfer paper of specific size loaded in an upper stage cassette 91 or lower stage cassette 92 is selected, a selection signal appears at one of input terminals 25-29 and when a copy start key is pressed, a restart signal appears at an input terminal 25 at specific timing obtained under sequence control. Consequently, the selection signal is outputted from one of delay circuits 20-23 and inputted to a restart clutch through an OR gate 24 to drive the registration roller 12 at predetermined proper timing.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electrostatic recording device that allows selection of transfer paper of a plurality of sizes.

(Prior art) Conventionally, an image of the original is optically scanned to form an electrostatic latent image on a photosensitive drum, and the latent image is developed, then transferred and fixed onto transfer paper, and the image of the original is copied. In an electrostatic recording device designed to do this, in order to quickly select a transfer paper of a size that corresponds to the size of the document, the transfer paper feeding section is equipped with, for example, two upper and lower paper feeding stages as a feeding means. A paper feed tray may be provided in addition to, or in addition to, a paper feed tray.

However, in this case, the paper path from the paper feed section to the registration roller for timing the leading edge of the image on the photosensitive drum and the leading edge of the transfer paper is different due to various constraints such as length and angle. .

For this reason, even if the transfer paper is of the same size, if it is fed from an upper cassette and a lower cassette, for example, the resistance of the feeding roller of each cassette, the paper path resistance, the amount of bite on the registration roller, The leading edge timing of the copied image differs depending on the difference in the loop amount and the like.

It is clear that this would be increased even more if the transfer paper was of a different size.

However, in the past, without taking the above points into account, the timing control of registration was performed in the same way regardless of the upper and lower stages, and was controlled in accordance with, for example, transfer paper having a slower timing.

(Object of the Invention) The present invention has been made in view of the above-mentioned points, and is a static registration system that enables the same registration timing to be obtained no matter which paper feed section a selected size of transfer paper is placed in. An object of the present invention is to provide an electronic recording device.

(Structure of the Invention) For this purpose, in the present invention, in an electrostatic recording device having a plurality of paper feed units, the registration timing is adjusted according to the selected size of transfer paper and the paper feed unit loaded with the transfer paper. I try to make them different.

(Example) Examples of the present invention will be described below. FIG. 1 schematically shows an electrophotographic copying device among electrostatic recording devices. When the original 2 is placed on the surface of the platen glass 1, the platen cover (not shown) is closed, and the copy start key is operated, the exposure light source 3 scans the original 2 for exposure in the direction of arrow a. A light image of the original 2 is guided to the surface of a photosensitive drum 6 as an image forming photosensitive member via a mirror 4.5. The photosensitive drum 6 is a grounded metal cylinder with a photoconductive layer made of selenium or the like provided on the outer peripheral surface thereof, and rotates in the direction indicated by the arrow in conjunction with the exposure scanning.

Before the optical image arrives on the photosensitive drum 6, the photoconductive layer is, for example, uniformly charged by the charging electrode 7 to which a DC high voltage is applied, and the photoconductive layer in this state receives the optical image. Then, the conductivity of the area that receives the light increases, and the electrical charge in that area escapes to the metal cylinder, and positive charges remain in the dark area depending on the degree of brightness, and this causes the photoconductive layer to An electrostatic latent image corresponding to the image of the original is formed on the surface of the document.

When the portion on which this electrostatic latent image is formed reaches the developing sleeve 8a of the developing device 8, the negatively charged developer is attracted to the remaining positively charged portion of the photosensitive drum 6 by electrostatic force. Ru. As a result, a developer image corresponding to the electrostatic latent image is formed on the surface of the photosensitive drum 6.

The transfer paper 10+ or 102 in the selected one of the paper feed cassettes 91 or 92 is completely fed out in the direction of the registration roller 12 by the feed roller 111 or 112 and once stopped, the leading edge of the transfer paper and the photosensitive The photosensitive drum 6 is sent out again from the registration roller 12 at a timing when the leading edge of the developer image on the drum 6 coincides with the transfer pole 13 to which a DC high pressure is applied to the transferred transfer paper. The developer image on the surface is transferred.

Thereafter, the transfer paper is separated from the photosensitive drum 6 by a separation electrode 14 to which AC high voltage is applied, and is sent to a fixing device 16 by a conveyor belt 15, where the developer image is fixed, and the receiver is discharged onto a tray 17.

Reference numeral 18 denotes a removing electrode for removing charges remaining on the photosensitive drum 6, and reference numeral 19 denotes a cleaning device for removing developer remaining on the surface of the photosensitive drum 6.

In this embodiment, in such a copying apparatus, the drive timing of the registration roller 12 is adjusted depending on whether transfer paper of a specific size is loaded in the upper cassette 91 or the lower cassette 92. ing.

This should be confirmed through experiments and studies for each paper size in the paper feeding system to be adopted in advance, and after knowing the absolute value of the amount, classifying it into combinations as shown in the table below, and correcting the registration. Let's do it. Note that "upper stage" means an upper cassette, "lower stage" means a lower cassette, rA3/B4J means transfer paper of size A3 or B4, and rA4/B5J means transfer paper of size A4 or B5. rPTJ means paper feed tray. In addition, "+" means to delay the timing determined by the sequence control that controls the whole, and "1" means that the timing is delayed from the timing determined by the sequence control that controls the whole, and "1" means one of the sequence pulses.
Corresponds to a pulse.

A delay circuit is used to correct the driving timing of the registration roller 12. FIG. 2 shows a control circuit for obtaining the registration timing, in which 20 to 23 are delay circuits equipped with gate circuits, and 24 is an OR gate. 25 is a restart signal input terminal for driving the registration roller; 26
27 is a selection signal input terminal for transfer paper when A3 or B4 size transfer paper is loaded in the upper cassette 91, and a selection signal input terminal for the transfer paper when the same size transfer paper is loaded in the lower cassette 92. Terminal 28 is a selection signal input terminal for transfer paper when A4 or B5 size transfer paper is loaded in the upper cassette 91, and 29 is a selection signal input terminal for the transfer paper when the same size transfer paper is loaded in the lower cassette 92. This is the selection signal input terminal. Reference numeral 30 is an output terminal for starting a restart clutch that drives the registration roller 12.

When the restart signal arrives, the delay circuits 20 to 23 are
When the selection signal arrives from the corresponding input terminal, the restart signal is delayed by a predetermined time (t1 to 1+ as shown in FIG. 3) and output to the OR gate 24.

Therefore, the upper cassette 9I or the lower cut 92 route,
A selection signal appears at one of the input terminals 25 to 29,
When the copy start key is pressed in this state, a restart signal appears at the input terminal 25 at a predetermined timing obtained by sequence control, so that a signal is output from the delay circuit to which the selection signal of the delay circuits 20 to 23 is input. The signal is output and input to the restart clutch via the OR gate 24, and the registration roller 12 is driven at a predetermined timing as shown in the table above.

Therefore, the registration roller 12 is always driven at an appropriate timing regardless of the size of the transfer paper or the position of the loaded cassette.

Note that although the case where a paper feed tray is used is not described above using circuit blocks, in this case, it is sufficient to increase the number of delay circuits. In addition, when designing, we determined the combination of the transfer paper size and the transfer paper feeding port (cassette position) at the start of copying, and used a computer to adjust the timing of the registration storage margin by arbitrarily storing it in memory. It can also be set in the area. Further, in addition to the size of the transfer paper and the paper feed section, the paper basis weight (weight) of the transfer paper can be added as a variable to the registration timing control.

(Effects of the Invention) As described above, according to the present invention, the registration timing can be properly controlled regardless of the size of the transfer paper or the loading position of the transfer paper, and misregistration can be prevented. .

[Brief explanation of the drawing]

Figure 1 is a schematic configuration diagram of an electronic copying machine, Figure 2 is a control circuit diagram for obtaining registration timing, and Figure 3 is a diagram of a control circuit for obtaining registration timing.
The figure is a timing chart. DESCRIPTION OF SYMBOLS 1...Platen glass, 2...Original, 3...Light source for exposure, 4.5...Mirror, 6...Photosensitive drum, 7
...Charging electrode, 8...Developing device, 9+, 92...
Paper cassette, 101.102...Transfer paper, 111%
112... Feeding port, -ra, 12... Registration roller, 13... Transfer pole, 14... Separation pole, 1
5... Conveyor belt, 16... Fixing device, 17...
Receiver is a plate, 18... Eliminating electrode, 19... Cleaning device, 20-23... Delay circuit, 24... OR gate, 25... Restart signal input terminal, 26.29...
- Selection signal input terminal, 30... output terminal.

Claims (1)

[Claims] (1) In an electrostatic recording device having multiple paper feed units,
An electrostatic recording device characterized in that registration timing is varied depending on the selected size of transfer paper and the paper feed section in which the transfer paper is loaded.