JPS63295285A - Image recorder - Google Patents

Abstract

PURPOSE:To achieve prevention of double recording of an image caused by a backlash, by a method wherein a return amount of a recording medium based on the backlash of a gear mechanism is detected and a recording head is kept on standby to be driven until the recording medium advances by said return amount when advance of the recording medium is resumed. CONSTITUTION:When a motor 9 is stopped by a pause or the like during recording, a drive roller 2 is reversed by a backlash of a drive gear 8, and a guide roller 4 is reversed by return of a recording paper 1. Then, when an encoder pulley 13 is reversed, B phase of an encoder 14 advances further than A phase, and an encoder reversion signal Q becomes [0] to perform counting operation of subtraction. The counted value successively decreases and a B phase signal cease to be outputted. When a control part 25 drives the motor 9 by ending of the pause or the like, the recording paper 1 advances again, the encoder reversion signal Q becomes [1] to perform counting operation of addition of B phase signal of the encoder 14. The B phase signal of the encoder 14 is outputted from a counter circuit 16 and driving of a recording head is resumed to perform recording.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to image recording devices such as profilers and printers that record in the main scanning direction without moving the recording medium in the sub-scanning direction, and in particular, This invention relates to an image recording device that prevents double writing of images caused by the return of a recording medium based on buff crash of a gear mechanism.

[Conventional technology]

As a conventional image recording device, for example, a discharge electrode array is arranged in the main scanning direction of a recording paper, and an electrostatic latent image is created on the recording paper conveyed in the sub-scanning direction by driving the discharge electrode array according to an image signal. There is an image recording device that forms images.

This image recording device includes a transport mechanism that transports the recording paper, a recording section that forms an electrostatic latent image on the recording paper by driving a discharge electrode array, and a system that visualizes the electrostatic latent image formed on the recording paper. It has a developing section and a fixing section for fixing the developed image. This image recording device is the block of the CAD system.
When used as a storage medium, the recording paper becomes large in size, such as AO size, so the conveyance mechanism is configured to receive torque from a drive source via a gear mechanism, which allows the recording paper to be delivered to a specified size. The paper is conveyed at a high speed in the sub-scanning direction. When a pulse signal is output from the encoder in accordance with the conveyance of the recording paper, an electrostatic latent image is formed in the main scanning direction of the recording paper under timing control of a control section that inputs this pulse signal. This electrostatic latent image is developed in a developing section, and the developed image is fixed in a fixing section, thereby producing the aforementioned large-sized recording (for example, drawings, etc.).

[Problem that the invention seeks to solve]

However, according to conventional image recording devices, when the recording operation is paused due to a pause or the like and then started again, the transport mechanism resumes driving from the pause, so the gear mechanism that transmits the drive torque is not activated when the gear mechanism is stopped. The recording paper that had returned in the opposite direction based on the rush passes through the recording head again, resulting in the inconvenience that the image is written twice on the recording paper.The double writing of the 0 image is a combination of continuous straight lines and curved lines. When recording drawings, etc., in which images are formed, the quality of the recording deteriorates, and in some cases, the drawings may become unusable.

[Means to solve problems]

The present invention has been made in view of the above, and in order to prevent the image from being written twice due to the backlash of the gear mechanism, the amount of return of the recording medium is detected, and when recording is resumed, the amount of the recording medium is adjusted by the amount of return. To provide an image recording device in which driving of a recording head is kept on standby for a period of time during which the recording head advances.

That is, the image recording apparatus of the present invention has the following means.

(1) Conveying means This is for moving the recording medium in the sub-scanning direction, and receives driving torque from a driving source via a gear mechanism.

(2) Recording Medium Movement Amount Detecting Means This detects the forward movement amount and return movement amount of the recording medium. For example, the rotation speed of a guide roller corresponding to the movement speed of the recording medium is detected via an encoder. Instead of the combination of a guide roller and an encoder, for example, a measuring mark may be attached to the recording medium and this may be read photoelectrically.

(3) Return movement amount storage means This is for storing the above-mentioned return movement amount, and uses, for example, an up/down counter that subtracts a count value by a pulse corresponding to the return movement amount of the encoder. However, instead of this, a configuration may be adopted in which a unique counter is provided to count up the amount of return movement and is compared with the count value of another counter that counts the amount of forward movement.

(4) A control means controls the entire system and causes the recording head to be driven on standby until the recording medium moves forward by an amount of movement equal to the amount of return when the recording medium returns due to bank lash of the gear mechanism of the transport mechanism.

[For production]

With the above configuration, when the return movement amount is output from the recording medium movement N detection means, the return movement amount is stored in the return movement amount storage means.

When the recording medium moves forward again from a temporary stop such as a pause, the recording head is started to be driven after moving forward by the amount of return movement.

〔Example〕

Hereinafter, the image recording apparatus of the present invention will be explained in detail.

FIG. 1 shows an embodiment of the present invention. For example, an AO-sized recording paper 1 is pulled out from a recording paper roll 3 by a drive roller 2, and while being supported by a guide roller 4, a portion of the recording paper 1 is pulled out from a recording head 5. It is supposed to pass through. The drive roller 2 has a drive gear 8 that meshes with a transmission gear 7 provided on a transmission shaft 6.
The transmission shaft 6 has a worm wheel 12 that meshes with a worm gear 11 provided on the drive shaft lO of the DC motor 9. The guide roller 4 has an encoder boot at one end.
When the encoder pulley 13 rotates, the encoder 14 outputs two-phase pulses A and H, which will be described later. The recording head 5 described above has a main electrode array (not shown) extending in the main scanning direction of the recording paper 1, and a counter electrode for positioning the recording paper 1 between the main electrode array and the main electrode array. Electric discharge is generated between the electric excavator and the opposing excavator by driving according to the signal. The A phase and B phase of the encoder 14 are a waveform shaping circuit 17 that shapes the encoder signal and removes the influence of noise.
The Q terminal of the flip-flop 15 is connected to a rotation direction determination input of a counter circuit 16, which will be described later. counter circuit 16
is connected to the counting input of The output of the counter circuit 16 is connected to an F/V conversion circuit 18 that converts the frequency of the output pulse into a voltage, and the output thereof is connected to a comparison circuit 19. A control voltage generation circuit 20 that outputs a control voltage is connected to the other input of the comparison circuit 19, and the output of the comparison circuit 19 is connected to a pulse width modulation circuit 22 via a low-pass filter 21. The output of the pulse width modulation circuit 22 is fed to a power amplifier 23, and the output is fed back to the power of the pulse width modulation circuit 22 and is also given to a drive circuit 24 that drives the DC motor 9. The entire system described above is controlled by a control section 25, and the recording head 5 is driven based on this control in accordance with an image signal read out from an image signal generation circuit 26 centered on an image memory.

Next, FIGS. 2(al) and 2(b) show the encoder pulley 13, encoder 14, and flip-flop 15 described above.
and a counter circuit 16, respectively. In FIG. 2(a), the encoder pulley 13 is supported by a rotating shaft 13a that rotates in response to the rotation of the guide roller 4, and has a concave portion 13b and a convex portion 13 on its outer periphery.
Further, the encoder 14 has a pair of photocouplers (not shown) at a predetermined interval, which are repeatedly activated and deactivated by light that passes through the concave portion 13b and is blocked by the convex portion 13C. One photocoupler is A
As the phase, the other photocouplers output a signal as the B phase to the flip-flop 15 via the waveform circuit 17.

On the other hand, in FIG. 2), the above-mentioned counter circuit 16
is an up/down counter 16a, three NOR circuits 1
6b, 16c, 16d, and two inverter circuits 1
6e and 16f, forming a circuit with the connections shown. Here, the counter circuit 16 is a flip-flop 1
U/D input that inputs the encoder reversal signal Q (rlJ is forward rotation, "0" is reverse rotation) of No.
Large input, Enable input that disables the counting operation by inputting the door open signal output when the plotter door is opened, and the count value is rFoJ(rl
1111J) or rOJ (rh.

Ripple carry output which outputs ``0'' when the count value is 00'') and ``1'' when the encoder boolean 1J13 is reversed, and a NOR circuit 16 to be described later.
It has an enable input and a load input for inputting the output of the inverter 16e and the output of the inverter 16e.

Note that the encoder signal may be input to the control section 25 from a source other than the output of the counter circuit 16. For example, it is also possible to input the signal from the waveform shaping circuit 17 to the control section 25.

Hereinafter, the operation for preventing double writing according to the present invention will be explained based on the timing chart shown in FIG. 3(a) (mountain).

When a command to start recording is input to the control unit 25, the control unit 25
causes the control voltage generation circuit 20 to output a reference control voltage. This control voltage is compared with the output of the F/V conversion circuit 18 corresponding to the zero rotational speed of the guide roller 4, and a pulse width modulation signal having a pulse width corresponding to the output with the maximum difference is output to the pulse width modulation circuit. output from 22. The power of the pulse width modulated signal is amplified to a predetermined level by the power amplifier 23, and part of the signal is fed back and sent to the drive circuit 23.
is input to drive the DC motor 9. The DC motor 9 is driven by rotating the drive roller 2 through a gear mechanism consisting of a worm gear 11, a worm wheel 12, a transmission gear 7, and a drive gear 8, and moves the recording paper 1 in the direction of the arrow (sub-scanning direction).
Transport to. This conveyance causes the encoder pulley 13 to rotate, and the encoder 14 outputs A-phase and B-phase pulse signals. At this time, the encoder pulley 13 is rotating normally, so the B phase lags the A phase, and the output (encoder reverse signal) Q of the flip-flop 15 is "1" (
Figure 3(a)). When the encoder reversal signal Q is "1", an addition counting operation is performed, but if the count value Q A"'Q o of the up/down counter 16a is now rFt+J, the ripple carry output is "0". Then,
The NOR circuit 16 is activated by “1” of the encoder reversal signal Q.
The output of b is rOJ, and the output of NOR circuit 16c is "l"
, the output of the inverter 16e becomes "0" and passes through the NOR circuit 16d, making the load input active.

Therefore, the B-phase signal of the encoder 14 is transmitted to the inverter 16.
f and input to the F/V conversion circuit 1st (3rd
Figure (b)). The speed of the drive roller 2 is increased based on the comparison output of the comparison circuit 19, and therefore the output of the F/V conversion circuit 18 becomes large.

As a result, the output of the comparison circuit 19 gradually decreases, and the DC motor 9 is controlled to a predetermined speed determined by the reference control voltage of the control voltage generation circuit 20. Control part 2
5 is the transport speed of the recording paper 1 based on the output of the counter 16;
In other words, the position in the sub-scanning direction is detected, the image signal is read out from the image signal generation circuit 26 at a predetermined recording timing, and the recording head 5 is driven according to the image signal to generate electrostatic charge on the recording paper 1. Form a latent image. After development, the electrostatic latent image is fixed, but this operation is self-explanatory and will not be explained here.

During this recording, if the DC motor 9 is stopped due to a pause or the like, the drive roller 2 is moved to the drive gear 8.
may be reversed due to backlash. When the drive roller 2 reverses, the recording paper 1 returns in the direction opposite to the arrow, and the guide roller 4 reverses. When the encoder pulley 13 is reversed due to this reversal, the B phase of the encoder 14 advances from the A phase, and the encoder reversal signal Q becomes "0" (FIG. 3(a)).

When the encoder reversal signal Q is "0", a subtraction counting operation is performed, and the counted value is "F□-1-rEnJ→rDn J→
It decreases to "C".

In this state, the ripple carry output becomes "1" and the output of the inverter 16e becomes "1", so the NO
The R circuit 16d assumes a non-passing state. Therefore, the B-phase signal of the encoder 14 is not output from the inverter 16f.

At the same time, the load input is inactive. When the control section 25 drives the DC motor 9 based on the end of the pause etc., the recording paper 1 moves forward again and the encoder reversal signal Q becomes "1". However, since the count value at this time is "CH", the ripple carry output is "1", and the B-phase signal of the encoder 14 is not output from the inverter 16f. This state continues until the count value reaches rF,j by the counting operation of adding the B-phase signal of the encoder 14. When the count value becomes “F)I”, the ripple carry output becomes “0”
Therefore, the output of the inverter 16e becomes "0" and NO
The R circuit 16d is brought into a pass state and the load input is activated. As a result, the B-phase signal of the encoder 14 is output from the counter circuit 16, and the drive of the recording head 5 based on this signal is resumed to perform recording. In this way, the recording paper 1 based on the backlash of the drive gear 8
Driving of the recording head 5 is put on standby until the recording paper 1 advances by a return amount of . As a result, it is possible to prevent the image from being written twice.

In the above embodiment, a 4-bit binary counter is used as the up/down counter 16a, so when the number of reverse pulses reaches 16, the count value becomes O ("FH" →
"0"), the ripple carry output becomes "0". At this time, the output of the NOR circuit 16d is the encoder reversal signal Q.
becomes "1" by "0", disables the enable input, and stops the counting operation. Therefore, the inverter 16f does not output a reverse pulse for the encoder 14. On the other hand, up/down counter 16
It is desirable that the number of bits of a be set according to the expected amount of backlash of the drive gear 8.

Further, in the above embodiment, the number of reverse rotation pulses is stored and the forward rotation pulse does not pass through the up/down counter 16a until the number of forward rotation pulses becomes equal to the number of reverse rotation pulses when forward movement is resumed. As mentioned above, a counter for counting forward rotation pulses and a counter for counting reverse rotation pulses are provided separately, and the forward rotation counter is reset at the time of reverse rotation, and when changing from reverse rotation to forward rotation, the count value of the forward rotation counter is The recording head may be driven on standby until the count value of the reverse rotation counter becomes equal to the count value.

Note that the present invention is not limited to the types of recording heads, types of recording paper, etc. described above. For example, it may be applied to an image recording device using a magnetic head, a thermal head, or the like.

〔Effect of the invention〕

As explained above, according to the image recording apparatus of the present invention, the return amount of the recording medium based on the backlash of the gear mechanism is detected, and when the recording medium resumes forward movement, the recording head is driven until it moves forward by this return amount. By waiting, it is possible to prevent the image from being written twice due to backlash of the gear mechanism.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. Figure 2 (
al. (b) is an explanatory diagram showing the encoder and counter circuit in FIG. 1; FIG. 3 (al, mountain) is a timing chart showing one embodiment of the present invention. Explanation of symbols■ ...--Recording paper 2 ......-Drive roller 3----1--Recording paper supply roll 4 ...--Guide roller 5 ... −・−Recording head 6−・−・−・−Transmission shaft 7 ・−・−・−Transmission gear 8−・−・・
−・−Drive gear 9 ・−・−・DC motor 10
-...-Motor drive shaft 1 construction-------Worm gear 12--Worm wheel 13----
・−Encoder wheel 14−・−・−・・Encoder

Claims (2)

[Claims] (1) In an image recording device that records an image in the main scanning direction on a recording medium that is conveyed in the sub-scanning direction, a conveying means that conveys the recording medium in the sub-scanning direction using a drive torque transmitted through a gear mechanism. and a detection means for detecting the forward movement amount of the recording medium in the sub-scanning direction and the return movement amount of the recording medium based on the backlash of the gear mechanism, and when the conveyance means stops conveying the recording medium. a storage means for storing the return movement amount detected by the detection means; and a storage means for storing the return movement amount detected by the detection means; when the transport means resumes transport of the recording medium in the sub-scanning direction, the return movement amount is equal to the return movement amount stored in the storage means. An image recording apparatus comprising: a control means that waits to record the image until the image is moved forward by the amount of movement. (2) The detection means is constituted by an encoder that outputs a forward pulse corresponding to the forward movement amount of the recording medium and a reverse rotation pulse according to the return movement amount, and the storage means is constituted by an encoder that outputs a forward rotation pulse corresponding to the forward movement amount of the recording medium, and a reversal pulse output from the encoder. The number of pulses of the reverse rotation pulse is memorized, and when the encoder outputs the forward rotation pulse following the reverse rotation pulse, the number of the normal rotation pulses is inputted until the number of pulses of the forward rotation pulse becomes equal to the number of reverse rotation pulses. 2. The image recording device according to claim 1, wherein the image recording device is configured to include an up/down counter that stops output, and wherein the control means makes recording of the image standby when the output of the forward rotation pulse is stopped. .