JPH03208074A - Image forming device - Google Patents

Abstract

PURPOSE:To make the operation speed of an image forming device main body variable and to execute the satisfactory fixing to the recording paper with the thickness of a wide range by correcting a driving clock of a motor and a system clock with the same ratio in accordance with the thickness of the recording paper. CONSTITUTION:Thickness of recording paper is detected by a recording paper thickness detecting sensor 23, and when it is detected that it is thick paper, a microprocessor 16 changes the setting of a timer value of an input/output port 18b so that the relation of printing speed and recording paper ream weight enters into a prescribed range, and makes a driving clock slower. Simultaneously, by changing a timer value of an input/output port 18a, a system clock is made slower by the same ratio as that of the driving clock. In such a manner, when the recording paper is thick, the printing speed is decreased, and when the recording paper is thin, the printing speed becomes higher, and satisfactory fixing can be executed against the thickness of the recording paper in a wide range.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a method for fixing toner on recording paper.
In particular, it relates to an electrophotographic image forming device or device that can switch the fixing time to multiple values depending on the type of recording paper. (Prior Art) Conventionally, in an image forming device used in an electrophotographic printer, a charged photosensitive drum is irradiated with a light source to form an electrostatic latent image on its surface, and toner is applied to the electrostatic latent image. After the toner image is deposited and developed, the toner image is transferred to a recording medium and fixed.

In the fixing device, the recording paper to which the toner is attached is sandwiched between a pair of rollers, fed at a constant speed, and heated at approximately constant pressure and temperature. In this case, it is said that by running the recording paper at a constant speed and heating it at a constant temperature, it is possible to uniformly fix images from thin to thick recording paper.

(Problem to be Solved by the Invention) However, in the above-mentioned image forming device, it is necessary to maintain the relationship between printing speed and recording paper amount within a predetermined range in order to achieve good fixation without causing offset or jamming. It is necessary to pay the

FIG. 5 is a fixing quality state diagram. The vertical axis is the recording paper weight (g
/rrf), and the horizontal axis shows the printing speed (m/sec).

As shown in the figure, in order to fix the image in a good condition, the relationship between the amount of recording paper and the printing speed must be within range A. This range A varies depending on the thickness of the recording paper and the running speed.
If this is not the case, fixing performance may deteriorate or paper wrinkles may occur. Therefore, it is difficult for conventional fixing devices to perform good fixing on both thin and thick recording paper.
Depending on the printing speed, the number of recording papers that can perform good fixing is limited.

On the other hand, if the fixing performance is improved by increasing the heating amount of the fixing heater, the power consumption of the fixing heater increases.

In addition, the motor that drives parts other than the fixing device of the image forming apparatus or the main body of the apparatus is made independent of the motor that drives the part of the fixing device,
The motor that drives the fuser part is rotated at a lower speed than the motor that drives parts other than the fuser, and a speed buffer is placed between the two parts to slow down the speed of the recording paper only when it passes through the fuser. There have been proposed methods for improving fixing properties (see Japanese Patent Application Laid-open No. 133073/1983). In this case, the image forming apparatus not only becomes large and complicated, but also requires two drive motors, which increases the cost.

The present invention solves the problems of the conventional image forming apparatus described above, and provides an image forming apparatus that can vary the operating speed of the main body of the image forming apparatus and can perform good fixing on a wide range of recording papers. The purpose is to

(Means for Solving the Problems) For this purpose, in the image forming apparatus of the present invention, a photosensitive drum whose surface is charged is exposed to light by an exposure device to form an electrostatic latent image, and the electrostatic latent image is transferred to a developing device. In an image forming apparatus that develops a toner image using a toner image, and then transfers and fixes the toner image onto recording paper, a drive motor that rotates a photosensitive drum is provided, and each roller rotates in conjunction with the drive motor. I am made to do so.

A motor drive circuit is provided to drive the drive motor, and a drive clock generated by a drive clock generation circuit is sent to the motor drive circuit.

Further, a system clock generation circuit is provided that generates a system clock for controlling the image forming process.

Both clocks are controlled in response to a signal indicating the recording plate thickness so that the relationship between the printing speed and the amount of recording paper falls within the range A in Figure 5, so that it is slow when the recording paper is thick and fast when the recording paper is thin. It is corrected to

At this time, both clocks are corrected at the same ratio.

(Function) According to the present invention, as described above, there is a drive clock for the drive motor provided to drive the photosensitive drum and each roller that rotates in conjunction with the photosensitive drum, and a system clock for controlling the image forming process. Since a means for correcting is provided, correction can be made by receiving a signal of the recording plate thickness via a recording plate thickness sensor or a switch provided on the operation panel.

In other words, when the recording paper is thick and the relationship between the printing speed and the amount of recording paper is at point B as shown in Figure 5, the timer value setting is changed and both clocks are slowed down, causing the printing speed to decrease. , move to point B2. Conversely, when the recording paper is thin, both crosses are sped up. (Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 3 is a schematic diagram of an image forming apparatus showing an embodiment of the present invention.

In the figure, a photosensitive drum 2 rotated in the direction of arrow a by a drive motor 1 is uniformly charged by a primary charger 3. As shown in FIG. Next, an exposure optical system element 4 such as an LED head exposes the photosensitive drum 2 to form an electrostatic latent image. The electrostatic latent image is developed by the developing device 5 to become a visible toner image, that is, a toner image.

On the other hand, the recording sheets are separated and fed one by one from the feeder 6 by the tie-up of the paper feed roller 7, or are fed from the manual feed table 8 by the timing operation of the paper feed roller.

Next, the registration rollers 9 send the recording paper to the transfer section in synchronization with the position of the toner image on the photosensitive drum 2. In the transfer section, the toner image is transferred onto recording paper by a transfer charger 10. The transferred recording paper is separated by a separation charger 11 and sent to a fixing device 12 where it is thermally fixed.

Thereafter, the photosensitive drum 2 is photostatically neutralized by the static eliminating device 13, the toner remaining on the surface is removed by the cleaning device 14, and the photosensitive drum 2 is prepared for the next printing process.

The above operation control is controlled by the mechanism control section 15.

FIG. 4 is a block diagram showing the structure of the mechanism control section.

In the figure, the m-structure control unit 15 is a microprocessor 16.
and program ROM 17, input/output ports} 18a-1
8c, exposure optical system control circuit 1 such as an LED head
It is composed of 9. The mechanism control section 15 is connected to the operation panel 2
0, is connected to the image forming control section 21 and the motor drive circuit 22. The microprocessor 16 is an oscillator 16
connected to a.

Here, the drive motor 1 is connected to the motor drive circuit 22, and the motor drive circuit 22 is connected to the input/output port 18b in the mechanism control section 15.

In order to drive the drive motor 1, a drive clock of, for example, 942.9 μs, which is generated by the timer of the input/output port 18b as a synchronous clock, is constantly applied to the motor drive circuit 2.
2. Furthermore, the drive motor 1 starts rotating in response to a start signal sent from the input/output boat 18b.

On the other hand, the operation of the mechanism control unit 15 is performed based on the system output of, for example, 4lS, which is activated by the timer of the human output baud H8a.

Next, FIG. 1 is a motor drive control circuit diagram of the image forming apparatus of the present invention.

In the figure, the thickness of the recording paper is detected by the recording plate thickness detection sensor 23, and when it is detected that the paper is thick, the microprocessor 16 changes the setting of the timer value of the input/output baud port 8b and slows down the driving clock. do.

With this operation, the drive clock 7 is changed so that the relationship between the printing speed and the amount of recording paper is within the range A in FIG. For example, if you want to reduce the printing speed by 30%, 1.41
4w. At this time, the timer value setting of the input/output port 8a is also changed to slow down the system clock. In this case, there are six 4+++s.

In FIG. 5, for example, when the printing paper weight is 90 g/g and the printing speed is 150 m/sec (point B+), sufficient fixing performance cannot be obtained. but,
Reduce printing speed by 30% to 100 wa/sec (B
, points>, good fixing performance can be obtained. FIG. 2 is another motor drive control circuit diagram of the image forming apparatus of the present invention.

In the figure, a recording plate thickness designation switch 24 is provided on an operation panel 20. Then, when the operator of the image forming apparatus operates the recording plate thickness designation switch 24 to specify thick recording paper, the microprocessor 16 operates the manual output port 18b.
Change the setting of the timer value to slow down the driving cloth.

On the other hand, if thin recording paper is specified, the setting of the timer value is changed to speed up the drive clock.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the Invention) As described above in detail, according to the present invention, the drive clock of the drive motor provided to drive the photosensitive drum and each roller that rotates in conjunction with the photosensitive drum, and the image forming process are controlled. Since a means for correcting the system clock is provided, when the recording paper is thick, both clocks are slowed down to reduce the printing speed, and when the recording paper is thin, both clocks are sped up to increase the printing speed. So,
Good fixing properties can be obtained for a wide range of recording paper thicknesses, and the range of usable recording papers can be widened.

[Brief explanation of drawings]

FIG. 1 is a motor drive control circuit diagram of an image forming apparatus according to the present invention, FIG. 2 is another motor drive control circuit diagram of an image forming apparatus according to the present invention, and FIG. 3 is a diagram showing an image forming apparatus according to an embodiment of the present invention. A schematic diagram of the apparatus, FIG. 4 is a block diagram showing part II of the mechanism control section, and FIG. 5 is a fixing quality status diagram. 1... Drive motor, 2... Photosensitive drum, 3...
Primary charger, 11... Separation IIF electric device, 16... Microprocessor, 1.7・ROM, 18a, 18b
, 18c... Input/output boat, 22... Motor drive circuit, 23... Recording plate thickness detection sensor, 24... Recording plate thickness designation switch.

Claims (1)

[Scope of Claims] A photosensitive drum whose surface is electrically charged is exposed to light by an exposure device to form an electrostatic latent image, the electrostatic latent image is developed by a developing device into a toner image, and the toner image is transferred to a recording paper. In an image forming apparatus that transfers images to a photosensitive drum and fixes the images, the image forming apparatus includes: (a) a drive motor that rotates a photosensitive drum; (b) a motor drive circuit that drives the drive motor; and (c) a drive that sends a drive clock to the motor drive circuit. (d) A system clock generation circuit that generates a system clock for controlling the image forming process; and (e) A system clock generation circuit that receives a recording plate thickness signal and corrects both clocks at the same ratio to generate a recording paper. An image forming apparatus characterized by having a means for slowing down when the image is thick and speeding up when the image is thin.