JPH0282280A - Toner thermal fixation mechanism for recorder - Google Patents

Abstract

PURPOSE:To reliably adjust the feeding speed of a recording paper according to the secular change of the diameter of a heat roller by adjusting the rotating speed of the heat roller according to an accumulated energizing time measured with the aid of a measuring means and keeping the feeding speed of the recording paper constant. CONSTITUTION:In a toner thermal fixation mechanism 20, the measuring means 26 measures the accumulated energizing time for the heat roller 21 having functional relation to the secular change of the diameter of the heat roller 21 and an adjusting means consisting of a servo motor 24, a motor driving circuit 25 and a control circuit 27 adjusts the rotating speed of the heat roller 21 according to the accumulated energizing time so as to keep the feeding speed of the recording paper constant. Thus, the feeding speed of the recording paper in the toner thermal fixation mechanism 20 can be reliably adjusted according to the secular change of the diameter of the heat roller 21.

Description

[Detailed Description of the Invention] [Summary] Regarding a toner heat fixing mechanism incorporated in an electrostatic recording device using toner, the present invention particularly relates to a toner heat fixing mechanism that is incorporated in an electrostatic recording device that uses toner, and is particularly applicable to color recording using toner of at least two of yellow, magenta, cyan, and black. The present invention relates to a toner heat fixing mechanism suitable for a recording apparatus in which the toner heat fixing mechanism is capable of adjusting the recording paper feeding speed in the toner heat fixing mechanism to one set according to the change in diameter of the heat roller over time. a measuring means for measuring the cumulative energization time to the heat roller;
A toner heat fixing mechanism characterized by comprising: an adjusting means for maintaining a constant recording paper feeding speed by adjusting the rotational speed of a heat roller and a backup roller according to a cumulative energization time measured by a measuring means. Configure.

[Industrial application field]

The present invention relates to a toner heat fixing mechanism incorporated in a recording device using toner, and particularly a toner heat fixing mechanism suitable for a recording device that performs color recording using toner of at least two colors of yellow, magenta, cyan, and black. Regarding.

[Conventional technology]

2. Description of the Related Art An electrophotographic recording device is known as a typical electrostatic recording device that uses toner as a recording medium. The recording process of an electrophotographic recording device includes an electrostatic latent image forming stage in which a photosensitive drum is charged and then exposed to light to form an electrostatic latent image on the photosensitive drum; There is a toner development stage in which an image is developed with toner, a toner transfer stage in which the developed toner is transferred to recording paper, and a toner fixation stage in which the transferred toner is thermally fixed.

Referring to FIG. 5, there is shown an outline of an electrophotographic recording apparatus that performs color recording using toners of four colors: yellow, magenta, cyan, and black. In FIG. 5, 1 is a recording paper cassette, 2 is a feeding roller, 3 is a registration roller, 4 is a gripper, 5 is an endless belt that conveys the gripper 4, and 6 is a drive pulley for the endless belt 5. Additionally, four toner recording machines 7V7 are installed along the upper running portion of the endless belt 5.
,．． 7c and 7. are arranged, and these toner recording machines 7
y, 7M, 7. and 7. are designed to record using yellow toner, magenta toner, cyan toner, and black toner, respectively. A plurality of recording papers S are held in a recording paper cassette 1, and the recording papers S are fed out one by one by a feeding roller 2. The recording paper S fed out by the feeding roller 2 is temporarily stopped by the registration roller 3, and after the timing with the gripper 4 is determined, the recording paper S is moved by the registration roller 3 at a speed that is somewhat higher than the moving speed of the gripper 4. sent out. When the leading end of the recording paper S is engaged with the gripper 4, the gripper 4
is closed by a suitable cam mechanism (not shown) to grip the recording paper S, and thereby the recording paper S is moved onto the endless belt 5.
Four toner recording machines were removed due to the movement of , IM, 1
It will pass through C and 7 degrees sequentially. Note that after the recording paper S is fed out by the registration rollers 3, the registration rollers 3 return to rotation at a predetermined constant speed.

Each of the toner recorders 'Iv, 1n, 1c and 7B has substantially the same configuration except that they use different colored toners. That is, each toner recording machine includes a photosensitive drum 8, a charger 9, an exposure system 10, a developer 11, a transfer device 12, and a cleaner 13. The photosensitive drum 8 is made of a photoconductive material, and exhibits insulating properties in the absence of light, but exhibits conductivity when irradiated with light. When performing a recording operation in each toner recording machine, first, a charger 9 is attached to the photosensitive drum 8.
Then, a recorded image is projected onto the photosensitive drum 8 by the exposure system 1O, and at this time, the charge in the light irradiation area is discharged by the photoconductive effect, and as a result, the photosensitive drum 8 is statically charged. A latent image is formed. The electrostatic latent image formed on the photosensitive drum 8 is developed by a developing device 114, and then a toner of a predetermined color (that is, yellow toner in the toner recording machine 7v, magenta toner in the toner recording machine 7H, and cyan toner in the toner recording machine 7c) It is recorded with toner (black toner on the 7m toner recording machine). The developed toner in each toner recording machine is transferred onto the recording paper S passing therethrough by a transfer device 12, and the toners of each color are superimposed as necessary. That is, the recording paper S is transferred to the toner recording machines 7V, 7.
．． , 7C, and 7°, color toners are superimposed in a predetermined mixed color area, resulting in desired color recording. Note that the positioning of the recording paper S with respect to the endless belt 5 is always determined by the gripper 4, so that the toners of each color are aligned and do not deviate from each other.

Is the recording paper S a toner recording machine? ,,7. ．． 1c and 7. When the toners of predetermined colors are sequentially transferred and the toners of each color are superimposed, the recording paper S is passed through the toner heat fixing mechanism 14, whereby the transferred toner is transferred to the recording paper S.
will be heat-fixed. The toner heat fixing mechanism 14 includes a heat roller 15 and a backup roller 16, and is the last toner recording device. Recording paper S with toner transferred by ,
is passed between the heat roller 15 and the backup roller 16, whereby the transferred toner is thermally fixed onto the recording paper S. To prevent the toner from being offset to the heat roller 15 side during heat fixing, the heat roller 1
5 is applied with silicone oil by a roller 17.

In the above conventional example, a toner heat fixing mechanism was described that is incorporated in an electrophotographic recording device that performs t-color recording using toner of four colors: yellow, magenta, cyan, and black. However, even in a monochrome electrophotographic recording device, A similar toner heat fixing mechanism is also incorporated in an electrostatic recording device that writes an electrostatic latent image on a dielectric drum using a needle electrode or the like.
[Problems to be Solved by the Invention] Now, it has been pointed out that in a conventional toner/heat fixing mechanism incorporated in a recording device, the heat roller gradually swells and increases its diameter by application of silicone oil. Furthermore, referring to the graph in FIG. 6, it is shown how the diameter of the heat roller changes when the heat roller is actually energized for several thousand hours. As the diameter of the heat roller increases over time, the circumferential speed of the heat roller gradually increases, and accordingly, the recording paper feeding speed of the toner heat fixing mechanism also increases.

By the way, in a recording device such as an electrophotographic recording device, in order to reduce the overall size, the toner heat fixing mechanism and the toner recording device are usually arranged close to each other, and as a result, the recording paper is not easily attached to the toner recording device. While the toner is being transferred, the recording paper is guided to a toner heat fixing mechanism. That is, in the conventional example shown in FIG. 5, the recording paper S is the last toner recording machine? .

While the toner is being transferred (in some cases, also in the toner recording machine 7c), the leading side of the recording paper S has already been introduced between the heat roller 15 and the backup roller 1G. For this reason, conventionally, the recording paper feeding speed in the toner heat fixing mechanism is made to match the recording paper moving speed during toner transfer.

However, as mentioned above, when the diameter of the heat roller increases over time and the recording paper feeding speed in the toner heat fixing mechanism becomes larger than the recording paper moving speed during toner transfer,
The recording paper is pulled toward the toner heat fixing mechanism, which causes stretching of the toner-transferred image, resulting in a decrease in the quality of the recorded image. In particular, with color recording as explained in Figure 5, problems arise not only with image stretching but also with color shift.Furthermore, in the case of color recording, the amount of toner to be thermally fixed is large, so it is necessary to apply sufficient heat to the toner. A soft roller is used as a heat roller to convey the information (in the case of a soft roller, the contact width with the recording paper, the so-called nip width, is large), but the soft roller swells to a large extent with silicone oil, so this problem is solved. It becomes even more serious.

In order to solve the above-mentioned problems, the diameter of the heat roller is made smaller in consideration of the amount of swelling of the heat roller, and this allows the recording paper feeding speed in the toner heat fixing mechanism to be adjusted to match the recording paper movement during toner transfer. Although it has been proposed to always make the speed slower than the speed, the same problem of deterioration in the quality of recorded images will occur in this case as well. To be more specific, since the recording paper feeding speed in the toner heat fixing mechanism is slower than the recording paper movement speed during toner transfer, the recording paper is bent between the toner heat fixing mechanism and the toner recording machine. As a result, if the recording paper is stiff, the recording paper will be pushed back toward the toner recording machine, resulting in shrinkage of the image and, in the case of color recording, color misregistration.

Furthermore, in order to solve this problem, as shown in FIG. 7, a reflective distance sensor 18 is applied to the heat roller 16 to measure the change in the diameter of the heat roller 16, and the heat roller is adjusted according to the measurement. It has also been proposed to adjust the speed of 16, but in this case, high measurement accuracy cannot be expected due to dirt on the heat roller surface such as silicone oil and toner, and dirt on the sensor itself, making it difficult to rely on the speed adjustment of the heat roller. The problem is that it is not possible to obtain gender. Another problem is that the heat resistance of the sensor must be increased because the interior of the toner heat fixing mechanism is in a high temperature environment.

Therefore, an object of the present invention is to provide a toner heat fixing mechanism incorporated in a recording apparatus that uses toner, particularly a toner that is suitable for a recording apparatus that performs color recording using toner of at least two of yellow, magenta, cyan, and black. It is an object of the present invention to provide a toner heat fixing mechanism that can reliably adjust the recording paper feeding speed in the toner heat fixing mechanism according to a change in the diameter of a heat roller over time.

[Means to solve the problem]

The means to solve the problem are as shown in Figure 1,
The toner heat fixing mechanism according to the present invention includes a measuring means for measuring the cumulative energizing time to the heat roller, and a recording paper feeding speed by adjusting the rotation speed of the heat roller according to the cumulative energizing time measured by the measuring means. and adjustment means for maintaining the same.

[For production]

In the toner heat fixing mechanism according to the present invention, the measuring means measures the cumulative energization time to the heat roller, which is in a functional relationship with the change in diameter of the heat roller over time, and the adjusting means maintains the recording paper feeding speed constant. The number of rotations of the heat roller is adjusted according to the cumulative energization time.

〔Example〕

Next, an embodiment of the toner heat fixing mechanism according to the present invention will be described with reference to FIGS. 2 to 4 of the accompanying drawings.

Referring to FIG. 2, a color electrophotographic recording apparatus incorporating a toner heat fixing mechanism according to the present invention is shown, and this color electrophotographic recording apparatus incorporates a toner heat fixing mechanism according to the present invention in place of a conventional toner heat fixing mechanism. This device is similar to the electrophotographic recording device shown in FIG. 5, except for the built-in mechanism.

Note that (in FIG. 2, the same reference numerals are used for the same components as in FIG. 5, and a description of these components will be omitted.

The toner heat fixing mechanism 20 includes a heat roller 21 and a backup roller 22 as in the case of FIG. The recording paper S on which the toner has been transferred is passed between a heat roller 21 and a backup roller 22, whereby the transferred toner is thermally fixed onto the recording paper S. In addition, in order to prevent the toner from being offset toward the heat roller 21 side during heat fixing, the heat roller 21
1 is coated with silicone oil by the roller 23, as in the case of FIG.

The toner heat fixing mechanism 20 includes, for example, a servo motor 24 as a motor for driving the heat roller 21, and power is supplied to the servo motor 24 by a motor drive, that is, a motor drive circuit 25. On the other hand, the heat roller 21
A measuring device, for example, an hour meter 26, is incorporated in the unit to measure the cumulative energization time, and this hour meter 26 starts when the color electrophotographic recording device is turned on, and stops when it is turned off. As a result, the time during which the heat roller 21 is energized is accumulated.

The toner heat fixing mechanism 20 further includes a control circuit 27 for controlling the motor drive circuit 25 according to the energization time accumulated in the hour meter 26, and this control circuit 27 is configured by a microcomputer. be done. As is clear from FIG. 2, the microcomputer includes a central processing unit 1 (CPtl) 2B and a read-only memory (ROM) that stores various programs, constants, etc. necessary for the operation of the color electrophotographic recording device. 29, - a writable/readable memory (RAM) that stores temporal data, etc.
30 and an input/output interface (Ilo) 31. In addition, as shown in Figure 2, the central processing unit (
CPII) 2B is set to 10 for example by clock 32.
An interrupt signal is input every 0 to 10p3.

Next, the operation of the toner heat fixing mechanism 20 described above will be explained with reference to FIGS. 3, 4A, and 4B.

FIG. 3 shows a routine for determining the cycle T of drive pulses to be output to the motor drive 25, and this routine is executed only once when the color electrophotographic recording apparatus is turned on. .

Note that when a drive pulse is output to the motor drive 25, the motor drive 25 supplies power to the servo motor 24 and drives it to rotate, but the rotation speed is determined by the length of the cycle T of the drive pulse, and the cycle T is As the period T becomes longer, it becomes slower, and as the period T becomes shorter, it becomes faster. Furthermore,
The routine may be executed every time a predetermined number of sheets are recorded after the power is turned on.

First, in step 301, data S is sent from the hour meter 26.
(that is, the cumulative energization time to the heat roller 21) is taken in, and then in step 302, the data S is RO
The signal is input as an address signal to a map stored in M29 in advance. As shown in step 302 in FIG. 3, this map is a one-dimensional map whose parameter is the cumulative energization time S to the heat roller 21, and the period T of the drive pulse is unique depending on the predetermined cumulative energization time S. is required. The relationship between the cumulative energization time S and the driving pulse period T is the fifth
It is determined based on the graph shown in the figure. To be more specific, the relationship between the cumulative energization time S and the period T of the drive pulse is determined by the recording paper feeding speed as the diameter of the heat roller 21 increases in order to keep the recording paper feeding speed in the toner heat fixing mechanism 20 constant. is determined to compensate for the increase in

Note that the period T of the driving pulse written in this map is
Since the data is discrete, the period T of the drive pulse for the predetermined cumulative energization time S is usually determined by complementary calculation. At step 303, the period T of the driving pulse determined at step 302 is written into the RAM 30, and with this writing, the routine shown in FIG. 3 ends.

Furthermore, the data in step 302 may be generated with high precision by using a function generator instead of the ROM table.

FIG. 4A shows an interrupt routine for generating a drive bus (I<) to be output to the motor drive 25, and in this interrupt routine, an interrupt signal is input to the CPo 28 at each predetermined period by the clock 32. is executed.

First, in step 401, the counter C is incremented by +1, and then in step 402, the counter number of the counter C is compared with a predetermined value P. The predetermined value P is a constant that determines the pulse width of the drive pulse, as shown in FIG. 4B, and is stored in the ROM 29 in advance. When the counter number of the counter C is smaller than the predetermined value P, the process advances to step 403 and the motor drive '
A high level voltage is applied to 25.

At this point, the routine in FIG. 4 ends once, but CPo 2
Steps 401, 402 and 403 are repeated for each interrupt signal to the motor drive 25 (that is, for each cycle), and unless the counter number of the counter C exceeds the predetermined value P, the motor drive 25 receives a high level voltage continues to be applied.

If the count of the counter C exceeds the predetermined value P while the routine of FIG. be done. The process then proceeds to step 405, where the counter number of counter C is compared with period T (determined by executing the routine of FIG. 3). As long as the number of counters in counter C does not exceed period T while the routine in FIG. 4 is executed sequentially in each period,
Steps 401, 402, 404 and 405 are repeated, and the low level voltage continues to be applied to the motor drive 25.

If the number of counters in counter C exceeds period T while the routine of FIG. 4 is being executed sequentially in each cycle, the process proceeds to step 406, where counter C is reset. When the counter C is reset, a high level voltage continues to be applied to the motor drive 25 again, and then a low level voltage continues to be applied to the motor drive 25. As a result, a drive pulse as shown in FIG. 4B is applied to the motor drive 25. Despite the increase in the diameter of the heat roller 21 over time, the recording paper feeding speed in the toner heat fixing mechanism is maintained constant.

[Action of the invention]

As is clear from the above description, in the toner heat fixing mechanism according to the present invention, even if the heat roller swells,
Since the recording paper feeding speed can be maintained constant, not only expansion and contraction of the recorded image but also color shift in the case of color recording does not occur, making it possible to perform high-quality recording. Furthermore, according to the present invention, the rotational speed of the heat roller is adjusted based on the cumulative energization time to the heat roller, which is in a functional relationship with the change in diameter of the heat roller over time. This allows for highly flexible control.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a toner heat fixing mechanism according to the present invention, and FIG.
The figure is a schematic diagram of a color electrophotographic recording device incorporating the toner heat fixing mechanism according to the present invention, and FIG. 3 determines the driving pulse cycle of the servo motor for driving the heat roller of the toner heat fixing mechanism shown in FIG. 2. FIG. 4A is a routine for explaining the operation of the toner heat fixing mechanism shown in FIG. 2, and FIG. 4B is a routine for driving the servo motor for driving the heat roller of the toner heat fixing mechanism shown in FIG. A waveform diagram showing the pulses, Figure 5 is a schematic diagram of a color electrophotographic recording device incorporating a conventional toner heat fixing mechanism, and Figure 6 is the relationship between the change in the diameter of the heat roller over time and the time it is energized. FIG. 7 is a schematic diagram showing a conventional example of measuring the change in diameter of a heat roller. 20... Toner heat fixing mechanism, 21... Heat roller, 22... Backup roller, 23... Roller 24... Servo motor,
25...Motor drive, 26...Hour meter,
27...Control circuit.

Claims (1)

[Claims] 1. A toner heat fixing mechanism (20) incorporated in a recording device using toner, including a measuring means (26) for measuring the cumulative energization time to the heat roller, and a toner heat fixing mechanism (20) that measures the cumulative energization time to the heat roller, and according to the energization time measured by this measuring means. A toner heat fixing mechanism comprising: adjusting means (24, 25, 27) for adjusting the rotational speed of the heat roller to maintain a constant recording paper feeding speed.