JPS5825677A - Transfer device - Google Patents

Abstract

PURPOSE:To perform invariably stable transfer by detecting the resistance value of recording paper fed prior to transfer, and then automatically controlling the amount of corona discharge by a corona discharger for transfer to the best value according to the detected resistance value. CONSTITUTION:The potential at a point (a) which corresponds to the resistance value (including the constant resistance value of a resist roller in this case) of recording paper 10 detected in a voltage drop method is classified into (n) stages through the comparison of a window comparator 19 composed of comparators CMP1-CMPn wherein (n) stages of reference voltages Vref1-Vrefn are set respectively, and a driver 20 is driven by the combination of high-level outputs of the comparators CMP1-CMPm (m=1-n) which corresponds to the classified potential at the point (a), thus adequately exercising control over the corona current or grid voltage of a corona discharger for transfer or control for varying its opening area or discharge distance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transfer device in a transfer type image recording system.

Generally, in an electrostatic or electrophotographic transfer type image recording system, an electrostatic latent image written on a recording medium by voltage application or exposure according to image information is developed with toner. The obtained image on the surface of the recording medium is transferred to the recording paper side by overlapping recording paper (plain paper) on the surface of the recording medium at the transfer position and applying corona discharge with a corona discharger.

Conventionally, in this type of transfer-type image recording system, a constant corona discharge is always applied by a corona discharger located at the transfer section, but depending on the resistance of the recording paper interposed between it and the recording medium, This determines the appropriate amount of corona discharge to perform stable transfer. Therefore, when performing transfer using various recording papers, it is necessary to create variations in the resistance to ensure stable transfer. There is a problem that people end up skimming it.

Figure 1 shows the relationship between the resistance value of the recording paper 10 and the amount of corona radiation appropriate for transfer.The lower the resistance value of the recording paper 10, the easier it is for corona ions to pass through the recording paper 10. Therefore, the amount of 1j corona discharge required for transfer must be reduced. At this time, if the amount of corona discharge is too high, most of the corona ions will pass through the recording paper 10 and be neutralized with the toner charge, resulting in no transfer. Also, when the resistance value of recording tv10 increases,
The corona radiation 1 is large enough to generate the electric field necessary to attract the toner image on the surface of the recording medium 1 toward the recording paper 10!
The amount required will be 7.

The present invention has been developed with these points in mind.Prior to transfer, the resistance of the fed recording paper is detected, and the corona radiation for transfer is adjusted according to the detected resistance value. Electrical VCg
2. A transfer-type image recording system that can automatically perform optimal control of the corona emission RL amount.
The present invention provides a transfer device that can be used to transfer images.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 shows an example of the configuration of an electrophotographic image recording system, in which a drum-shaped photosensitive recording medium 10 rotating in the sub-travel direction is appropriately arranged around the image recording medium 10, and the image recording system is charged, exposed, developed, and
Each predetermined process of transfer → static elimination → cleaning (3) is executed sequentially according to the rotation of the recording medium 1. The charging corona discharger 2. N source unit 3 which performs exposure according to image information in the main scanning direction. Developer device 4
．． Corona discharger for transfer 5. Paper separation claw 6. Static eliminator 7
2 and a cleaner 8, a paper feeding system consisting of a paper feed roller 111, a separation pad 122, and a registration roller 13, which feed the recording paper 10 in the cassette 9 to the transfer section by swimming as appropriate; It is composed of a belt mechanism 14 that conveys the recorded paper, a fixing unit 15 that performs a fixing process on the conveyed recording paper, and a paper discharge roller 16 that discharges the fixed recording paper to a tray 17. There is.

In the image recording system configured as described above, in particular, in the transfer device according to the present invention, both of the paired registration rollers 13 are formed of a conductive material as shown in FIG. By applying a constant DC voltage VCC through R, the resistance of the recording paper 10 passing between the registration rollers 13 is detected by the voltage drop method (4), and based on the detected resistance value. The control circuit controls the corona discharge amount of the transfer corona discharger 5 to a preset optimum value. 2. In the figure, 18 indicates a toner image.

2. Specific means for controlling the amount of corona discharge of the transfer corona discharge device 5 include a method of connecting a variable resistor in series to the main electrode for corona discharge to control the corona current, and a method of controlling the corona current by using a grid. In particular, there is a method of controlling the grid voltage and a method of controlling the size of the corona discharge aperture area by means of a mask.

A possible method would be to control the discharge distance using the movement mechanism of the corona discharger itself.

FIG. 3 shows an example of the configuration of a control circuit, in which a The potential at the point is set to n-stage reference voltages Vreft to Vre.
Comparator CMPI~ where fn is set respectively
A window comparator 19 consisting of CMPn compares and divides into n stages, and comparators CMP1 to CMPm (m =
1 to n) Control of the corona current or grid pressure of the transfer corona discharger 5, or control of changing its opening area or discharge distance, by driving the driver 4 by a combination of the outputs of Nohi L/H/L/ I am trying to do this as appropriate.

Therefore, in the transfer apparatus according to the present invention, the amount of corona discharged by the transfer corona discharger 5 is automatically controlled optimally according to the resistance value of the recording paper 10 being fed, and 4! Even when an rs recording rope is used, proper transcription can always be performed.

2. The roller for detecting the resistance value of the recording paper 10 is not limited to the registration roller 13, and a pair of feed rollers provided in the paper feeding system may also be used. It goes without saying that a roller or an IT main electrode may be separately provided.◎ As described above, in the transfer device according to the present invention, the static X latent image written on the recording medium according to the image information is In an image recording system that develops with toner and transfers the developed toner image to recording paper by corona discharge, a voltage IJn is applied between electrodes that sandwich the fed recording paper to increase the resistance of the recording paper. By providing a means for detecting the resistance value and a means for controlling the amount of corona emission by the corona mixer to a preset optimum value according to the detected resistance value. It has the advantage that stable transfer can be performed at all times depending on the type of recording paper with various resistances (lf!).

[Brief explanation of the drawing]

Figure 1 is a diagram showing the characteristics of the amount of corona discharge with respect to the recording resistance for optimal transfer. Figure 2 is a diagram showing an example of the construction of a general R, H transfer type image recording system. Figures 1 and 3 are simplified diagrams showing a specific means for detecting the resistance of recording paper, and Figure 4 is an electrical wiring diagram showing a specific example of a configuration for controlling the amount of corona discharge. It is. 1... Recording medium 5... Corona release device for transfer] O
...Note 'Mfdt 13...Registration roller 1
9...Windcon Valley '9 20... Driver applicant's agent Kiyoshi Torii

Claims (1)

[Claims] The image is written on a recording medium in accordance with the image information, the accumulated image is developed with toner, and the developed toner image is transferred to recording paper by corona discharge, and the paper is fed. A means for detecting the resistance value of the recording paper by applying a voltage Vr between the electrodes that sandwich the recording paper, and a means for detecting the resistance value of the recording paper by applying a voltage to the corona sheet. A transfer device configured by providing means for controlling li1 so that