JPS59109079A - Pressure controlling system of pressure fixing device - Google Patents

Abstract

PURPOSE:To enable uniform developing and transferring of a toner image by designating the width of a toner image supporting medium and positioning loading devices at optimum loading position. CONSTITUTION:A fixing roller 1 and an opposite roller 2 are supported parallel to a frame 3 and connected at one end with gear and rotated simultaneously. Plural loading devices 4, 5, 6 are provided in a space enclosed by a pressure bar 18 and the frame 3. The loading devices 5, 6 are movable in axial direction and driving belts 14, 15 are connected to move in axial direction of the fixing roller 1, and can be moved in axial direction by A, B motors 16, 17. On the other hand, the loading device 4 is fixed to axial direction. Magnets 7 are attached to loading devices 5, 6. Loading position of loading devices 5, 6 is detected by Hall element sensors 8-12 attached on a base plate 13 and shifted to specified position according to the width of the toner image supporting medium 19.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure control method for a pressure fixing device that fixes a toner image on a support medium by conveying the toner image support medium under pressure by a pair of parallel rollers that are in pressure contact with each other. It is something.

Recently, pressure fixing devices have come to be used as fixing devices in electrophotographic recording apparatuses due to their advantages such as safety, energy saving, and no need for warm-up time. However, one problem with pressure fusing devices is that it is necessary to uniformly apply a fairly high pressure to the toner support medium, which increases the size of the device.

Furthermore, in the electrophotographic recording method, development and transfer to a toner image supporting medium are generally based on one side, and when toner image supporting media of various widths are pressure-fixed, wrinkles may occur uniformly. There was a limit to how well it could be established without any problems.

In response to these problems, the applicant filed a patent application in 1984-845.
In No. 00, we proposed a pressure fixing device in which the loading means is movable in the axial direction of the roller and can be moved to an appropriate pressure position according to the width of the toner image supporting medium. It was not possible to apply a load to the pressure position.

Therefore, in the present invention, the load is applied to the optimum pressurizing position simply by specifying the medium width.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is an axial sectional view of a pressure fixing device showing an embodiment of the pressure control method of the pressure fixing device of the present invention, and FIG. 2 is a sectional view taken along the line AA' in FIG.

In FIGS. 1 and 2, the fixing roller 1 and the opposing roller 2 are supported in parallel by a frame 3, and are connected at one end by a gear so that they are rotated at the same time. A plurality of loading means 4, 5, -6 are provided in the space surrounded by the pressurizing par 18 and the frame 3,
The loading means 5, 6 are movable in the axial direction and are connected to a drive belt 14, 15 for axial movement of the fixing roller 1, and are provided so as to be movable in the axial direction by an A motor 16 and a B motor 17. It is being On the other hand, the grape loading means 4 is fixed in the axial direction.

A magnet 7 is attached to each of the load means 5 and 6, and the load position of the load means 5 and 6 is detected by Hall element sensors 8 to 12 attached on the substrate 13, and the toner image is supported. The media 190 is moved to a predetermined position depending on its width.

Next, before explaining the specific process by which the loading means 5 and 6 move, first, the substrate 13 is prepared in advance so that pressure fixing can be applied uniformly over the entire width of the toner image supporting medium 19.
Hall element sensors 8 to 12 are arranged above.

FIG. 3 is a block diagram of a circuit for driving the loading means, and 20 is a block diagram of a circuit for driving the loading means, and numeral 20 indicates A at the Hall element sensor position shown in FIG.
, 82 first Hall element sensor groups, and 21 are the fourth
The second Hall element sensor group of four C, D, E, and F shown in the figure, 22 is a 4-bit A memory circuit, 23 is a 2-bit B memory circuit, and 24 is sent from a medium width detection circuit (not shown). A C storage circuit 25 stores the 3-bit medium width code, as shown in FIG.
- When inputted as I2, the conversion circuit converts it into a 6-bit code indicating the position and outputs it as 00-05. 26 is the first latch circuit that latches the output 0°-03 of the conversion circuit 25. 27 is the conversion circuit. A poor latch circuit latches the output 04.05 of 25, 28 and 29 are comparison circuits, 30
〜33 is a flip-flop (hereinafter referred to as ``le now''), 34
is a dart circuit, and 35 to 38 are drivers.

Further, FIG. 5 is a diagram showing the relationship between the medium width and the pressing position in code, and the position where the Hall element sensor becomes n i I+ is the pressing position.

Assuming that the loading means 4, 5.6 are in the initial position,
The first Hall element sensor group 20 and the second Hall element sensor group 21 output the same code as the initial pressure signal in FIG. '10' is memorized. Next, when the medium width of B4 horizontal is set, 'o' is stored in the C storage circuit 24.
oo” is set.Furthermore, the first
The latch circuit 26 has 'oioo'", the second latch circuit 2
"01°" is output to 7. Then, the output "'010"
The comparison circuit 28 compares the output ``0''' and the output ``0001'' of the A storage circuit 22, and sets the output of 〉 to the F/F 31. Furthermore, the output ゛°01''
10'' is compared in the comparator circuit 29 and the output is F/F 3
Set to 2. When the motor start signal is input, the gate circuit 34 opens and among the drivers 35 to 38, motor A (CwON) driver 36 and motor B (CCwON) driver 37 operate, and motor A1
6 moves clockwise, and motor B17 moves counterclockwise. As a result, the pressure position position signal changes, and this pressure position position signal and the 6-bit conversion code (A + B-
The motor stops when Os + 04 + C-F = 03 to Oo) match each other. Printing is then started, and the B4 horizontal size support medium is printed through the steps of development, transfer, and fixing. If the media width changes to A4 vertical on the way, the conversion diagram in Figure 6 is compared with the current pressure position signal and the driver motor A is compared.
(CCWON) (7) Driver 35 motor B (
CwON) is output to the driver 38 for operation. Incidentally, the motor star <= symbol and printing operation are performed according to the time chart shown in FIG.

In the above embodiment, a Hall element was used as a position sensor for the load means, but it is also possible to connect a slotted, two-tooth disc to the drive belt and add the number of pulses generated by rotation to move the load means to a predetermined position. is also possible.

As described above in detail, according to the present invention, the loading means can be moved to the optimum pressing position and stopped by simply specifying the width of the toner image supporting medium.

[Brief explanation of drawings]

FIG. 1 is an axial sectional view of the pressure fixing device showing one embodiment of the pressure control method of the pressure fixing device of the present invention, a second cross-sectional view is taken along the line AA' in FIG. 1, and FIG. 3 is the same loading means. Figure 4 is a diagram showing the arrangement of the Hall element sensor, Figure 5 is a diagram showing the coded relationship between the media width and the pressure position position, and Figure 6 is the diagram showing the media width. A diagram showing codes and conversion data, and FIG. 7 is a diagram showing a time chart of printing operation. DESCRIPTION OF SYMBOLS 1... Fixing roller, 2... Opposing roller, 3... Frame, 4,5.6... Loading means, 7... Magnet, 8°9, . 10, 11.12... Hall element sensor, 13... Substrate, 14. L5... Drive belt, 1
6... Motor A117... Motor B118... Pressure bar, 20... First Hall element sensor group, 21...
・Second Hall element sensor group, 22...A memory circuit, 2
3...B memory circuit, 24...C memory circuit, 25...
・Conversion circuit, 26...1st circuit, 27...2nd latch circuit, 28.29...comparison circuit, 30-33.
・Flip-flop (F/F), 34...key-
circuit, 35-38...driver. Patent applicant Oki Electric Industry Co., Ltd. Figure 2 Nog Figure 7

Claims (1)

[Claims] In the pressure control method of a pressure fixing device that fixes a toner image by applying pressure to the toner image support medium between a pair of parallel rollers that are in pressure contact with each other, a pressure fixing device that is movable in the axial direction of the rollers and that applies a load to the rollers is used. a plurality of loading means to be applied, a plurality of sensors for detecting the current position of the loading means, and moving and stopping the loading means so that the plurality of loading means are detected by a predetermined sensor according to the width of the toner image supporting medium. A pressure control system for a pressure fixing device, comprising a control circuit for positioning a loading means at an optimum loading position by specifying the width of a toner image supporting medium.