JPH03238471A - Paper feeding control system for recorder - Google Patents

Abstract

PURPOSE:To prevent the shrinking and color slippage of a recorded image caused by the carrying failure of a recording sheet by providing a fixing roller control part adjusting the speed of revolution of a motor driving a fixing roller based on the measured deflection quantity of the recording sheet and controlling the deflection quantity of the recording sheet so as to be set within a prescribed range. CONSTITUTION:The deflection quantity of the recording sheet 3 passing between an image carrier 1 and the fixing roller 2 is measured by a deflection quantity measuring means 5 provided between the image carrier 1 and the fixing roller 2. Then, the speed of revolution of the motor 4 driving the fixing roller 2 is accelerated or reduced according to the deflection quantity of the recording sheet measured on the fixing roller control part 6, and controlling is carried out so that the deflection quantity of the recording sheet 3 is set within a prescribed range. Thus, the carrying failure of the recording sheet 3 is prevented, and high-definition color recording without having the shrinking and color slippage of the image is carried out.

Description

Detailed Description of the Invention ([Required] A recording device that includes an image carrier that transfers toner to a recording paper, a fixing roller that fixes the toner transferred to the recording paper to the recording paper, and a motor that drives the fixing roller. Regarding the device, in order to eliminate recording paper conveyance defects caused by changes in the paper feed speed of the fixing roller due to swelling of the fixing roller, etc., and to prevent shrinkage and color shift of recorded images due to such conveyance defects, the fixing roller and image carrier are A deflection amount measuring means for measuring the deflection amount of the recording paper passing between the image carrier and the fixing roller for the purpose of providing a method for keeping the deflection amount of the recording paper passing between the image carrier and the fixing roller within a predetermined range. and a fixing roller control section that controls the amount of deflection of the recording paper to be within a predetermined range by controlling the rotation speed of the motor that drives the fixing roller based on the measured amount of deflection of the recording paper.

(Industrial Application Field) The present invention relates to an image bearing member of an electrophotographic recording device, an electrostatic recording device, etc. that transfers toner to recording paper, and a fixing roller that fixes the toner transferred to the recording paper. The present invention relates to a paper feed control method for a recording apparatus having a motor for driving a fixing roller, and particularly for recording a color image on recording paper using a plurality of image carriers.

(Prior Art) FIG. 6 shows an example of a conventional color electrophotographic recording device. The conveyance system of the apparatus includes a recording paper cassette 601, a feed roller 602, a registration roller 603, a gripper 604, a belt 605 for conveying the gripper, and a driving pulley 606 for the belt. Recording process (
(4) to (3) are each composed of the same members, and include a photosensitive drum 610, a charger 611, an exposure system 612, a developing device 613, a transfer device 614, and a cleaner 615. Four sets of these are installed side by side, and color recording is performed by forming a toner image of each color in order and transferring it onto the recording paper 600 in an overlapping manner. After this, 600 sheets of recording paper
The toner image is sent to a fixing device 620, and the toner image is fixed on the recording paper 600 by heat and pressure applied from a fixing roller 621 and a pressure roller 622.

By the way, the diameter of the fixing roller 621 is set so that the silicone oil applied via the roller 623 to prevent toner from adhering penetrates into the fixing roller 621.
When the paper swells over time and is driven at a constant rotation speed, a phenomenon occurs in which the paper feeding speed in the fixing device 620 becomes faster than a predetermined speed.

On the other hand, in order to reduce the overall size of the printer, the fixing device 620 is placed near the photosensitive drum 610 of the recording process (2), and when the recording paper 600 enters the fixing device 620, it is still in the recording process (2) (of the recording paper). Depending on the length, there may be a recording process m) in which transfer is performed. Therefore, the feeding speed of the fixing roller 621 is lower than that of the photosensitive drum 611.
■ Recording process by faster than the feed rate.

In addition to image distortion occurring in (2), color shift occurred between recording processes I and II and (2) and (2), resulting in a decrease in image quality.

[Problem to be solved by the invention]

By the way, conventionally, as a countermeasure to the above problem, the fixing roller 6
The paper feed speed of the fixing roller 621 is made slightly slower by making the roller diameter smaller in anticipation of the swelling of the fixing device 620 and the photosensitive drum 610 of the recording process (2).
A method has been adopted in which the recording paper 600 is bent between the two. This deflection attempts to absorb the speed difference between the two. However, in the initial state where the fixing roller 621 is not swollen, there is a large difference between the feeding speed of the fixing roller 621 and the feeding speed of the photosensitive drum 610, and the recording paper 620 is
A large deflection of 0 occurs. In this case, since the recording paper 600 is stiff, the force of the recording paper 600 to return to its original state exceeds the recording paper retention force of the photosensitive drum 610, and as a result, the recording paper 600 slips against the photosensitive drum 610, and after slipping, The paper feeding speed is the speed of the fixing roller 621, which is slow. Therefore, with this method, it is difficult to avoid problems such as image shrinkage and color shift.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, an object of the present invention is to make it possible to maintain a constant deflection between a fixing roller and a photosensitive drum that is an image carrier.

(Means for Solving the Problems) In order to solve the above technical problems, the present invention, as shown in FIG. 1, includes an image carrier 1 that transfers toner onto a recording paper 3;
In a recording device that includes a fixing roller 2 that fixes the toner transferred to the recording paper 3 onto the recording paper 3 and a motor 4 that drives the fixing roller, the recording that passes between the image carrier 1 and the fixing roller 2 is used. The amount of deflection of the recording paper 3 is within a predetermined range by adjusting the rotation speed of the total deflection measuring means 5 that measures the amount of deflection of the paper 3 and the motor 4 that drives the fixing roller 2 based on the measured amount of deflection of the recording paper. The fixing roller control unit 6 controls the fixing roller so that

(Operation) The paper feed control system of the recording apparatus according to the present invention operates as follows.As shown in FIG. , the amount of deflection of the recording paper 3 passing between the image carrier 1 and the fixing roller 2 is measured.Next, the fixing roller control section 6 controls the fixing roller 2 according to the measured amount of deflection of the recording paper. The rotational speed of the driving motor 4 is accelerated or decelerated to control the amount of deflection of the recording paper 3 within a predetermined range.

(Example) Next, examples of the present invention will be described.

Figure 2 shows the constituent countries according to the example. The conveyance system of the apparatus includes a recording paper cassette 201, a feed roller 202, a registration roller 203, a gripper 204, a belt 205 for conveying the gripper, and a drive pulley 20 for the belt.
Consists of 6. Each of the recording processes (I to ■) is composed of the same members, including a photosensitive drum 210 as an image carrier, a charger, a developer, a transfer device, and the like.

Four sets of these are installed side by side, and color recording is performed by sequentially forming toner images of various colors and overlappingly transferring them onto the recording paper 200. The fixing device 220 includes a fixing roller 221 and a pressure roller 222, and the toner image is fixed onto the recording paper 200 by heat and pressure applied thereto. At this time, in order to prevent toner from adhering, silicone oil applied via the roller 223 penetrates into the fixing roller 221, causing the fixing roller 221 to swell over time. The amount of deflection is determined by measuring the distance between the recording paper 200 and the distance sensor 250 using a distance sensor 250 using an ultrasonic element. The fixing roller control section 260 includes an ADDC motor 280 and a signal processing section 2.
62, ROM section 264, DA converter 263,
A DC motor driver 265 and a DC motor 280
The rotation speed of the fixing roller 221 is controlled via the fixing roller 221. The signal processing unit 262 compares the signal of the amount of deflection of the recording paper output from the distance sensor 250 with the reference amount of deflection held by the signal processing unit 262, and stores the signal in the ROM unit 26 according to the comparison result.
Specify address 4. Here, for the signal from the distance sensor 250, in order to eliminate errors such as fluctuations in the deflection of the recording paper, the deflection amount δ is the average value of n data (n is a natural number) for − measurements. ROM section 2
64, the number of rotations of the fixing roller 221 is set to a minimum number of rotations Nm1n so that a substantially predetermined feed speed can be obtained even if the diameter of the fixing roller 221 changes from the initial stage to after the oil has swelled.
, Ml (=Nmin) 9M between maximum rotation speed N max
2. ...Data for setting 16 stages of Ml6 (= Nmax) is written, and the signal processing unit 2
Based on the address specified by 62, the 16 stages of data (8 bits) are output. DA converter 26
3 is based on the data output from the ROM section 264,
A command voltage to be given to the DC motor driver 265 is generated. The DC motor driver 265 rotates the DC motor 280 connected to the fixing roller 221 according to the command voltage.

A flowchart for controlling the rotation of the fixing roller 221 in this embodiment is shown in FIG. For example, the current fixing roller 22
Assume that the rotation speed of 1 is ML. Measured value of deflection δ
is less than the minimum value δmin, the rotational speed of the fixing roller 221 is decelerated to Mi-1. On the other hand, δ is the maximum value δmax
If the rotation speed of the fixing roller 221 exceeds Mi
Accelerate to ll. In other cases, the fixing roller 221
The setting value of the feed speed will remain the same as before.

The operation will be explained below based on FIG.

The recording paper 200 taken out from the paper cassette 201 is
The gripper 20 is temporarily stopped by the registration roller 203.
4, the paper is fed out from the registration rollers 203 at a speed slightly higher than the feeding speed of the gripper 204. When the leading edge of the recording paper 200 enters the gripper 204, the gripper 204 closes and grips the recording paper 200. Thereafter, the registration roller 203 returns to constant speed rotation.

When the leading edge of the recording paper 200 reaches a predetermined position from each recording process (Steps to ■), image exposure on each photosensitive drum 210 is sequentially started, and the recording paper 200 is
A color superimposed image is recorded on 00. After the recording process (IV) is completed, the recording paper 200 is fed into the fixing device 220 and the image is fixed.

After the leading edge of the recording paper 200 enters the fixing device 220, the recording paper 200 begins to bend due to the difference in paper feeding speed between the fixing roller 221 and the photosensitive drum 210. After the time Tl until the deflection starts to occur until the rear end of the recording paper 200 passes the photosensitive drum 210, the fixing roller is controlled five times for each TO time as shown in FIG. The unit 260 measures the amount of deflection of the recording paper 200 and controls the number of rotations of the fixing roller 221.

Now, suppose that the paper feeding speed of the fixing roller 221, which is driven at a rotational speed of Mi, is slightly faster than the predetermined speed V1 due to the oil swelling of the fixing roller 221.
Even after T1 time has passed since 0 entered the fixing device 220, the measured deflection amount remains below the minimum reference value δmin.

At this time, the fixing roller control unit 260 controls the fixing roller 2
The rotation speed of 21 is changed to Mi-1, which is one step lower. As a result, the paper feeding speed of the fixing roller 221 also becomes low, and the amount of deflection of the recording paper increases. Even in the second and subsequent deflection measurements, the deflection still remains at δmin.
If it is below, the rotation speed of the fixing roller 221 is successively changed to the lower speed side until the amount of deflection exceeds δmin. If the amount of deflection exceeds δmin and is between δmaX, the set value of the rotation speed is not changed. However, the amount of deflection is δ
When the rotation speed exceeds max, the rotation speed is changed to one step faster (see FIG. 5).

By performing such control, the amount of deflection of the recording paper 200 passing between the fixing roller 221 and the photosensitive drum 210 of the recording process (rV) can be kept within a predetermined range, and as a result, the recording paper can be conveyed well. The transfer position for the recording process (IV) can be set at a predetermined position.

Note that the set value of the number of rotations of the fixing roller 221 set in the fifth measurement of the amount of deflection of the recording paper 200 is retained as is, and is used as the initial value of the number of rotations of the fixing roller 221 when fixing the next recording paper 200. By doing so, changes in the speed of the fixing roller can be minimized.

In addition, by writing the current value of the rotation speed of the fixing roller 221 into the non-volatile memory, after the power is turned off,
When recording is started again, the optimum rotation speed can be set for the fixing roller 221.

In this example, a distance sensor using an ultrasonic element was used to measure the amount of deflection of the recording paper. Of course, a sensor of this type may also be used.

Further, it is also applicable to transfer type recording devices other than electrophotographic devices.

(Effects of the Invention) As explained above, in the present invention, the amount of deflection of the recording paper passing between the image carrier and the fixing roller becomes too large or too small due to, for example, swelling of the fixing roller. In order to prevent conveyance defects, a deflection amount measuring means is provided and the rotation speed of the fixing roller is controlled based on the measurement result so that the deflection amount falls within a predetermined range.

Therefore, there is no problem in conveyance of the recording paper, and as a result, high-quality color recording without image expansion/contraction or color shift can be performed, which is useful.

[Brief explanation of drawings]

! ! 81 is a principle block diagram of the present invention, FIG. 2 is a configuration diagram according to an embodiment, FIG. 3 is a rotation control flowchart of the fixing roller, FIG. 4 is an explanatory diagram (part 1) according to the embodiment, and FIG.
The figure is an explanatory diagram (part 2) according to the embodiment, and FIG. 6 is the constituent countries according to the conventional example. 1, (210)... Image carrier (photosensitive drum) 2.22
1...Fixing roller 3.200...Recording paper 4, (280)...Motor (DC motor) 5, (25
0)... Deflection amount measuring means (distance sensor) 6.260... Fixing roller control section

Claims (1)

[Claims] An image carrier (1) that transfers toner to recording paper (3);
In a recording apparatus that includes a fixing roller (2) that fixes the toner transferred to the recording paper (3) onto the recording paper (3) and a motor (4) that drives the fixing roller, the image carrier (1) and the fixing roller are provided. A deflection measuring means (5) for measuring the deflection of the recording paper (3) passing between the roller (2) and the recording paper (3).
) and the fixing roller (2) based on the measured amount of deflection of the recording paper.
The number of rotations of the motor (4) that drives the recording paper (
3) A fixing roller control section (6) that controls the amount of deflection to be within a predetermined range.