JPS5854362A - Detection for separation failure of transfer paper in copying machine - Google Patents

Abstract

PURPOSE:To use a conventional device to detect surely the separation failure of a transfer paper inexpensively, by detecting the separation failure on a basis of a current of a destaticizing charger, flowing to a casing, which is changed in accordance with the presence or the absence of the transfer paper. CONSTITUTION:A casing 7b of a discharging charger 7 is connected to one terminal of a comparing amplifier 14 through voltage dividing resistances 12 and 13, and a reference current to be compared is connected to the other terminal. The current flowed to the casing 7b is changed in accordance with the absence or the presence of a transfer paper facing to the discharging charger 7. If the transfer paper is not separated and comes, an H-level output is generated from the amplifier 14. When an output signal is generated from an AND gate 16, a separation detection signal SE is outputted to stop the machine. Consequently, since monitoring the current of the casing of the destaticizing charger 7 suffices for this detection, the separation failure is detected inexpensively and surely.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting transfer paper separation errors in a copying machine.

Generally, in copying IfIA, after an image is formed on a photoreceptor and developed, it is transferred to optical transfer paper fed at a predetermined timing by a transfer charger, and the transferred transfer paper is transferred to a separating means. While the toner is separated from the photoreceptor and sent to a fixing section, residual toner on the photoreceptor is cleaned by cleaning means after the separation process is completed. and ζ
When the transferred transfer paper passes through the separation means, an abnormal situation may occur in which it is not separated due to misalignment of the tie ring, and is wrapped around the photoreceptor and sent to the cleaning means side intact. be. If the transfer paper gets caught in the cleaning blade or 7-hoo brush used as a cleaning means due to such a mistake in separating the transfer paper, it will not be possible to damage these cleaning means or the surface of the photoreceptor, resulting in cleaning failure or abnormal images. This causes the occurrence of

Therefore, conventionally, a reflective photosensor is provided between the separating means and the cleaning means and facing the photoreceptor.
Some machines use this photosensor to detect the presence or absence of transfer paper at the positions, and if the presence of transfer paper is detected, the machine is stopped. However, this method requires the addition of a new 7-photo sensor that is dedicated to detecting transfer paper separation errors, which increases costs and requires space to install this photo sensor on the W8 photoreceptor. There is, and it becomes even more dramatic.

The present invention has been made in view of these points, and is a method for detecting transfer paper separation errors in a copying machine, which is cheaper and more compact than using existing devices, and is capable of reliably detecting transfer paper separation errors. The purpose is to obtain a method.

The present invention first takes into consideration the fact that some copying machines are provided with a static elimination charger as cleaning auxiliary means between the cleaning means and the separation means in order to facilitate the cleaning of residual toner by the cleaning means. Focusing on the fact that the current flowing through the kenishing of the static elimination charger changes when there is transfer paper in the opposing position, we have designed a system that can detect transfer paper separation mistakes using such existing devices. Nine things.

An embodiment of the present invention will be described based on the drawings.

First, the photosensitive drum (1) rotating in the direction of the arrow is surrounded by a charger (2), an exposure optical system (3), a developing unit (4), a transfer charger (5),
A separation conveyance belt (6) to which a predetermined bias voltage is applied and which serves as a separation means, a static elimination charger (7), and a cleaning blade (8) as an example of a cleaning means are provided in this order. Then, the registration straw 2 (9) feeds the transfer paper αQ to the transfer position by the transfer charger (5) at a predetermined timing, and the transferred transfer paper (G) is separated from the photosensitive drum (1) by the conveyance belt (6). ) and sent to the fixing roller cll.

Here, the static elimination charger (7) acts as an auxiliary cleaning means, and its charge wire (
A constant current and high voltage is applied to the 7 photoreceptor drums (1
) weakens the electrostatic adhesion between the residual toner on the surface of the photoreceptor drum (1) and facilitates cleaning of the residual toner with the cleaning blade (8).1. This type of configuration has been adopted in the past, and the eleventh one is adopted in this embodiment.

However, the casing (74) of the static elimination charger (7)
is connected to one terminal of the comparator amplifier o4 via the voltage dividing resistor (2) (2), and the current flowing through the casing (7) is connected to the variable resistor connected to the other input terminal of the comparator amplifier a4.
It is set to be compared with the reference current of 11@.

Here, the reason why the current flowing through the casing (To 7) is detected is that the level is different depending on whether there is a transfer paper (T) or not at the position opposite to the neutralization charger (7). It is set so that an output of H level is generated from this comparator amplifier α◆ by one novel current flowing through the casing (74) when there is transfer paper (to).The output from this comparator amplifier cL4 is ANDed.
It is input to the gate (b). The output from the timer (b) is also input to this palm gate (b). Here, this timer (B) is activated when the transfer paper (G) is fed by the registration roller (9) and its tip is connected to the static elimination charger (7).
This function counts and outputs the time it takes to reach the end of the casing (74) of the casing (74) based on the resist drive signal. 74) This is to prevent false detection and increase reliability by monitoring the current flowing through K.

Therefore, according to this embodiment, the existing device can be
By simply using the charger (7) and monitoring the current flowing through the casing (74), the gate (
When an output signal is generated from (to), this is used as the transfer paper separation error detection signal Sz, and this signal can be used to perform processing such as stopping the machine, and is inexpensive and small in size.

As mentioned above, the present invention utilizes a static elimination charger used as a cleaning aid, and detects transfer paper separation errors based on changes in the current flowing through the casing.・It is small and can perform reliable detection.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, with FIG. 1 being a schematic side view and FIG. 2 being a circuit diagram. DESCRIPTION OF SYMBOLS 1... Photoreceptor drum (photoreceptor), 6... Separation conveyance belt (separation means), 7... Static elimination charger, 8...
Cleaning blade (cleaning means), 1o...
・Transfer paper application person Ricoh Co., Ltd. 'f'>Z diagram

Claims (1)

[Claims] a separating means for separating the transferred transfer paper from the photoreceptor;
A cleaning means for cleaning 1 iK of toner remaining on the surface of the photoreceptor after separation is provided, and a static eliminating charger to which a constant current and high voltage is applied acts as a cleaning aid means is located between the separating means and the cleaning means. In the copier provided with the above-mentioned copying machine, a transfer paper separation error is detected based on the current flowing through the casing of the static elimination charger, which changes depending on the presence or absence of the transfer paper at a position facing the charge elimination charger on the photoreceptor. A method for detecting transfer paper separation errors in copying machines.