JP3360166B2 - Image recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet for driving a conveying means for intermittently conveying a recording sheet by a required amount in a predetermined direction along with the progress of recording by a recording head, such as a dot impact printer. A transport drive source,
The present invention relates to an image recording apparatus having a platen driving source for rotating and driving a platen roller, independently of each other.

[0002]

2. Description of the Related Art Generally, in an image recording apparatus using a platen roller, a gap between a recording surface of a recording sheet mounted on the platen roller and a recording head is very small. In the case of a recording sheet having a partially thick sheet, the recording sheet may be caught between the recording head and the platen roller and may be torn.

For this reason, a motor for conveying the recording paper and a motor for rotating the platen roller are used in common, and the motor rotates the platen roller via the belt, thereby utilizing the slip between the belt and the platen roller. In order to prevent the recording paper from being damaged, a configuration is adopted.

However, when such a configuration is adopted, when a recording operation and a paper feeding operation are alternately repeated as a general printing operation, an image recording apparatus such as a dot impact printer capable of performing high-speed recording uses a paper. Since the time given for feeding is extremely short, the platen roller cannot be stopped due to inertial force even when the motor is stopped. As a result, the platen roller rotates during recording by the recording head, and the print quality is significantly degraded. .

In order to prevent such deterioration in print quality,
Some image recording apparatuses capable of high-speed recording, such as dot impact printers, have a configuration in which printing is performed while the platen roller is fixed without rotating. In this image recording apparatus, the gap between the recording head and the platen roller is widened to prevent the recording paper from being damaged.

However, in such a configuration, various inconveniences occur due to a wide gap between the recording head and the platen roller. For example, when such a configuration is employed in a dot impact printer, the stroke between the head pin becomes larger than a specified value due to the large gap between the recording head and the platen roller, and the root of the head pin wears out, shortening the service life. However, the operation rate and reliability of the image recording apparatus are reduced.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been conceived in view of the above circumstances, and it is possible to prevent damage to a recording sheet without widening a gap between a recording head and a platen roller, and furthermore, to prevent a platen due to inertia force from being generated. An object of the present invention is to provide an image recording apparatus capable of preventing deterioration of print quality due to a delay in stabilization of a roller.

In order to solve the above problems, the present invention provides:
The following technical measures have been taken:

According to a first aspect of the present invention, there is provided an image recording apparatus having a recording head, a platen roller, and conveying means for intermittently conveying a recording sheet by a required amount in a predetermined direction, the conveying means comprising: And a platen drive source for rotating and driving the platen roller, and when the required transport amount of the recording paper is equal to or greater than a predetermined amount, or when the thickness of the recording paper is equal to or greater than a predetermined thickness. When the drive source for the platen is activated while the drive source for the paper transport is in operation, if the required transport amount of the recording paper is less than the predetermined amount, or if the thickness of the recording paper is less than the predetermined thickness, the paper transport An image recording apparatus comprising: a platen drive source control unit that stops the platen drive source during operation of the drive source.

The recording paper may be cut paper,
It may be continuous paper.

As a recording method using a recording head, an impact method, a thermal transfer method, or the like can be adopted, but it is not limited to these.

A stepping motor can be used as a sheet-conveying drive source or a platen drive source, but the drive source is not limited to this.

The platen drive source control means is a CPU (central processing) that operates based on a predetermined program.
unit), but is not limited to this. The platen drive source control means controls the platen drive source based on one of the required transport amount of the recording paper and the thickness of the recording paper.

According to a preferred embodiment, when the platen drive source is operated, the platen drive source control means stops the operation of the platen drive source before the stop of the operation of the paper transport drive source. Let it.

According to a second aspect of the present invention, there is provided an image recording apparatus comprising a recording head, a platen roller, and a conveying unit for intermittently conveying a recording sheet by a required amount in a predetermined direction. , A platen drive source for rotating and driving the platen roller, and a platen drive source being activated by starting the operation of the platen drive source, thereby stopping the operation of the paper transport drive source. And a platen drive source control unit for stopping the operation of the platen drive source before the image recording apparatus.

According to a preferred embodiment, the platen drive source control means sets the time from the stop of the operation of the platen drive source to the stop of the operation of the sheet transport drive source in proportion to the required transport amount of the recording paper. Or the platen drive source is controlled so as to be in inverse proportion to the thickness of the recording paper.

The time from the stop of the operation of the platen drive source to the stop of the operation of the paper transport drive source may be continuously varied according to the required transport amount of the recording paper or the thickness of the recording paper. Alternatively, it may be changed stepwise.

According to another preferred embodiment, the platen drive source control means controls whether the transport speed of the recording paper by the platen roller is equal to or less than the transport speed of the recording paper by the transport means, and The platen drive source is controlled so as to be proportional to the thickness of the recording paper.

The transport speed of the recording paper by the platen roller may be varied continuously or stepwise according to the required transport amount of the recording paper or the thickness of the recording paper.

According to another preferred embodiment, there is provided a lock means for preventing the rotation of the platen roller when the paper feed drive source is not operating.

As the lock means, an electromagnetic clutch can be employed, but the invention is not limited to this.

According to another preferred embodiment, there is provided a lock means for preventing rotation of the platen roller when the platen driving source is not operating.

According to another preferred embodiment, the control operation by the platen drive source control means is inhibited based on the instruction operation by the user, and the operation of the platen drive source is controlled in accordance with the instruction operation. It has control means.

According to the present invention, the presence or absence of rotation of the platen roller is switched according to the required transport amount of the recording paper and the thickness of the recording paper, or the platen roller is rotated before the stop of the operation of the paper transport driving source. Since the operation of the drive source is stopped, it is possible to prevent the recording paper from being damaged without widening the gap between the recording head and the platen roller, and to prevent the deterioration of the print quality due to the delay in stabilizing the platen roller due to the inertial force.

That is, when the required transport amount of the recording paper is small, or when the recording paper is thin, the recording paper is not damaged without rotating the platen roller. Therefore, the platen roller is not rotated. As a result, it is possible to prevent the print quality from deteriorating due to the stabilization delay of the platen roller. In addition, if the operation of the platen drive source is stopped before the stop of the operation of the paper transport drive source, a sufficient stabilization time for the platen roller can be ensured, so that printing due to a delay in the stabilization of the platen roller can be achieved. Quality degradation can be prevented. Also, unlike the case where the platen roller is always fixed, it is not necessary to increase the gap between the recording head and the platen roller. Therefore, the gap between the recording head and the platen roller, such as damage to a head pin in an impact printer, is increased. Can be avoided.

Further, if the rotation of the platen roller is prevented by the lock means when the paper feeding drive source is not operating, the platen roller may be rotated by the impact at the time of recording by the recording head. And printing quality can be maintained more favorably.

If the rotation of the platen roller is prevented by the locking means when the platen driving source is not operating, the stabilization time of the platen roller can be further reduced, and the printing quality can be improved. It can be better maintained.

[0028] Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a schematic side view of a main part of an impact printer as an example of an image recording apparatus according to the present invention. In the gap between a recording head 1 and a platen roller 2, recording paper made of continuous paper is provided. 3 and the ink ribbon 4
Is located. The recording paper 3 is conveyed by the upper tractor 5 and the lower tractor 6 in the direction of the arrow.
The upper tractor 5 and the lower tractor 6 are rotationally driven by a paper transport drive source 7 composed of a stepping motor via a pulley 7 a attached to an output shaft of the paper transport drive source 7 and an endless belt 8. The tension of the endless belt 8 is adjusted by a tension roller 9.

FIG. 2 is a schematic plan view of a main part of the impact printer shown in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line AA in FIG. It is attached to a linear shuttle 12 that can reciprocate. Although not shown, the recording head 1 has one in the main scanning direction.
Fourteen head blocks each having 288 head pins, two in the sub-scanning direction and 24 in the sub-scanning direction, are provided along the main scanning direction.

A pulley 14 is attached to one end of the rotating shaft 13 of the platen roller 2.
And a platen driving source 15 composed of a stepping motor
An endless belt 18 is wound around a pulley 17 fixed to the output shaft 16. The tension of the endless belt 18 is adjusted by a tension roller 19.

The pair of upper tractors 5 is attached to the rotating shaft 21 and transports the recording paper 3 by using transport holes 22 formed at predetermined intervals at both ends in the width direction of the recording paper 3. The pair of lower tractors 6 is attached to a rotating shaft 23, and conveys the recording paper 3 using conveyance holes 22 formed at predetermined intervals at both ends in the width direction of the recording paper 3.

At one end of the rotating shaft 13 of the platen roller 2, an electromagnetic clutch 24 as a locking means is mounted. When the electromagnetic clutch 24 is not energized, the rotating shaft 13 is turned off. 13 is mechanically locked to prevent the rotation of the rotating shaft 13, and when the built-in solenoid is energized, the mechanical locking of the rotating shaft 13 is released to allow the rotating shaft 13 to rotate.

FIG. 4 is a schematic circuit block diagram of the impact printer shown in FIG.
MPU (micro processing unit) for paper feed motor control
The platen drive source 15 is controlled by a motor control signal from a platen motor control MPU 32. Electromagnetic clutch 2
4 is controlled by an excitation control signal from the paper feed motor control MPU 31. MPU31 for paper feed motor control
And the platen motor control MPU 32 is
An operation signal from an operator panel 34 having a key switch group operated by a user is input to the upper MPU 33 which is controlled by the upper MPU 33. An encoder signal is input from the paper feed drive source 7 to the paper feed motor control MPU 31, and an encoder signal is input from the platen drive source 15 to the platen motor control MPU 32. Although not shown, MPU 3 for controlling the paper feed motor
1 and the platen motor control MPU 32
(Read only memory) and RAM (random access memor)
y) and a timer circuit are connected to the bus.

Next, an outline of the operation will be described. At the time of recording,
The head pins of the recording head 1 are selectively protruded and driven in accordance with the image data, and the tips of the head pins contact the recording surface of the recording paper 3 via the ink ribbon 4. As a result, the ink of the ink ribbon 4 is transferred in the form of dots on the recording surface of the recording paper 3, and an image corresponding to the image data is recorded. At this time, since the movement of the recording paper 3 in the paper thickness direction is restricted by the platen roller 2, the recording paper 3 does not escape due to the impact of the head pin. Such an operation is repeated with the movement of the linear shuttle 12 along the support rod 11, and an image for one band is recorded on the recording surface of the recording paper 3.

When an image for one band is recorded by one forward or backward movement of the linear shuttle 12, the upper MP
A paper feed operation is commanded from U33 to the paper feed motor control MPU 31, whereby the paper feed motor control MPU 31
Outputs a motor control signal to the paper transport drive source 7. As a result, the output shaft of the paper-conveying drive source 7 rotates, and the rotating power is transmitted through the pulley 7a and the endless belt 8 to the rotating shaft 2
The recording paper 3 is conveyed in the direction of the arrow in FIG. The transport amount at this time is determined by the distance between the already recorded area and the area to be recorded next, and the paper transport drive source 7 is driven by the number of steps corresponding to the transport amount. That is, in an area where images such as characters and figures to be recorded are continuous in the transport direction of the recording paper 3, the recording paper 3 is transported by the recording width of the recording head 1 in the sub-scanning direction. In a blank area or a boundary between pages, the recording paper 3 is conveyed by a distance longer than the recording width of the recording head 1 in the sub-scanning direction.

At this time, the MPU 31 for controlling the paper feed motor
Accordingly, the electromagnetic clutch 24 is controlled, and while the paper-conveying drive source 7 is operating, the lock of the rotating shaft 13 by the electromagnetic clutch 24 is released, and the platen roller 2 becomes rotatable. Platen roller 2 is an MP for platen motor control.
Depending on the required transport amount of the recording paper 3, the recording paper 3 may be rotated or not rotated, and even when the recording paper 3 is rotated, the stop of the operation of the platen driving source 15 is determined by the paper transport. Although it is different from the time when the operation of the drive source 7 is stopped, the behavior of the platen roller 2 and the platen drive source 15 will be described later in detail.

As described above, each time the linear shuttle 12 moves forward and backward, recording by the recording head 1 and paper feeding by the paper transport drive source 7 are repeated, and an image is recorded on the recording paper 3.

FIG. 5 is a flowchart for explaining a control processing procedure of the platen drive source 15 by the platen motor control MPU 32 shown in FIG. 4. The behavior of the platen roller 2 will be described with reference to this flowchart.

First, the platen motor control MPU 32
It is determined whether a paper feed operation command has been input from the upper MPU 33 (S1). That is, since the paper feed operation command from the upper MPU 33 is simultaneously supplied to both the paper feed motor control MPU 31 and the platen motor control MPU 32, it is checked whether the paper feed operation command has been input.

If a paper feed operation command is input from the upper MPU 33 (S1: YES), the platen motor control MP
U32 determines whether or not the number of drive steps of the paper transport drive source 7 is equal to or greater than a predetermined number of steps (S2). That is, since data relating to the required transport amount of the recording paper 3 is also input from the upper MPU 33 together with the paper feed operation command, it is checked whether the required transport amount is equal to or greater than a predetermined value.

If the number of drive steps of the paper transport drive source 7 is equal to or greater than the predetermined number of steps (S2: YES), the platen motor control MPU 32 calculates the number of drive steps for driving the platen drive source 15 ( S3). That is, since the platen roller 2 is heavy and has a large inertial force, even if the operation of the platen drive source 15 is stopped, the platen roller 2 continues to rotate due to the inertial force.
When the operation stop time of the platen drive source 15 is matched with the operation stop time of the paper transport drive source 7, even if the recording by the recording head 1 is started, the rotation of the platen roller 2 does not stop, and the print quality deteriorates. Therefore, the number of drive steps of the platen drive source 15 is calculated so that the stop time of the operation of the platen drive source 15 is set before the stop time of the operation of the paper transport drive source 7.

At this time, the time from the stop of the operation of the platen drive source 15 to the stop of the operation of the paper transport drive source 7 is set so as to be proportional to the transport amount of the recording paper 3 by the paper transport drive source 7. The number of drive steps of the platen drive source 15 is calculated. That is, when the transport amount of the recording paper 3 is large, the rotation time of the platen roller 2 is long, and the rotation speed is increased as described later. As a result, the accumulated energy becomes large, so that much time is required for stabilization. Therefore, the time from the stop of the operation of the platen drive source 15 to the stop of the operation of the paper transport drive source 7 is increased.

The platen motor control MPU 32
Calculates the drive speed of the platen drive source 15 (S
4). That is, when the transport amount of the recording paper 3 is large and the difference between the peripheral speed of the upper tractor 5 and the lower tractor 6 and the peripheral speed of the platen roller 2 is large, the recording paper 3 is easily damaged. The driving speed of the platen drive source 15 is calculated such that the transport speed of the recording paper 3 by the upper tractor 5 and the lower tractor 6 is equal to or less than the transport speed of the recording paper 3 by the upper tractor 5 and the lower tractor 6. You do it.

The platen motor control MPU 32
Starts driving the platen driving source 15 (S5).
That is, the supply of the drive pulse to the platen drive source 15 is started. As a result, the output shaft 16 of the platen drive source 15 rotates, and the rotating power is transmitted to the rotating shaft 13 via the pulley 17, the endless belt 18, and the pulley 14, and the platen roller 2 rotates.

FIG. 6 is an explanatory diagram for explaining the relationship between the rotation of the output shaft of the paper transport drive source 7 and the rotation of the output shaft 16 of the platen drive source 15. Rotation speed of output shaft of drive source 7 and drive source 1 for platen
5, when the rotation speed of the output shaft 16 is equal, the peripheral speed of the upper tractor 5 and the lower tractor 6 is equal to the peripheral speed of the platen roller 2. 6, the vertical axis represents the rotation speed, and the horizontal axis represents the number of drive steps. The rotation of the output shaft of the platen drive source 15 is indicated by a solid line, and the rotation of the output shaft 16 of the paper transport drive source 7 is indicated by a solid line. This is indicated by a chain line. As is clear from FIG. 6, the driving stop time of the output shaft 16 of the platen driving source 15 is earlier than the driving stop time of the output shaft of the paper transport driving source 7, and the output shaft of the platen driving source 15 is stopped. The rotation speed of 16 is lower than the rotation speed of the output shaft of the paper-conveying drive source 7. This is because the platen motor control MPU 32 drives the platen drive source 15 based on the calculation results in steps S3 and S4. By controlling the platen roller 2 in this manner, it is possible to prevent the recording paper 3 from being damaged. The aim is to achieve compatibility with the prevention of print quality deterioration.

Next, the platen motor control MPU 32
It is determined whether the driving of the platen driving source 15 has been completed (S6). That is, it is checked whether the platen driving source 15 has been driven by the number of steps calculated in step S3.

When the driving of the platen driving source 15 is completed (S6: YES), this routine is completed. Even if the driving of the platen driving source 15 is terminated, the platen roller 2 continues to rotate due to the inertial force. However, at this point, the sheet conveying driving source 7 is being driven and the recording paper 3 is being conveyed. Since the recording by the recording head 1 is not performed, the print quality does not deteriorate even if the platen roller 2 rotates. When the driving of the paper transport drive source 7 is completed, the platen roller 2 is settled. That is, the advance deceleration amount shown in FIG. 6 is set by estimating the time required for stabilizing the platen roller 2 from an empirical value or the like.

In step S6, if the driving of the platen driving source 15 has not been completed (S6: NO), the process returns to step S6 and waits for the driving of the platen driving source 15 to be completed.

In step S2, if the number of drive steps of the paper transport drive source 7 is not equal to or greater than the predetermined number of steps (S2: NO), this routine is terminated. That is,
The fact that the number of drive steps of the paper transport drive source 7 is not more than the predetermined number of steps means that the required transport amount of the recording paper 3 is less than the predetermined amount. When the platen roller 2 is rotated, the platen roller 2 cannot be settled and the stabilization time of the platen roller 2 cannot be secured. Since the rotation continues and the print quality deteriorates, the platen roller 2 is not rotated.

In step S1, if a paper feed operation command has not been input from the upper MPU 33 (S1: N
O), the process returns to step S1 to wait for a paper feed operation command from the upper MPU 33.

The above operation is a mode in which the rotation of the platen roller 2 is automatically controlled. The user manually controls the rotation of the platen roller 2 by performing a predetermined operation on the key switches on the operator panel 34. Mode. That is, by performing a predetermined operation on the key switches on the operator panel 34 by the user, it is possible to prevent the platen drive source 15 from being operated while the sheet transport drive source 7 is operating, or The driving source 15 for the platen may always be operated while the driving source 7 for conveyance is operating.

In the above embodiment, the advance deceleration amount and the drive speed of the platen drive source 15 are determined according to the transport amount of the recording paper 3. However, the advance deceleration amount of the platen drive source 15 is determined. Alternatively, the drive speed may be determined according to the thickness of the recording paper 3. The platen drive source 1 by the platen motor control MPU 32 at this time
5 will be described with reference to the flowchart shown in FIG.

First, the platen motor control MPU 32
It is determined whether a paper feed operation command has been input from the upper MPU 33 (S11). That is, since the paper feed operation command from the paper feed motor control MPU 31 is simultaneously supplied to both the paper feed motor control MPU 31 and the platen motor control MPU 32, it is checked whether the paper feed operation command has been input. .

If a paper feeding operation command is input from the upper MPU 33 (S11: YES), the platen motor control M
The PU 32 determines whether the thickness of the recording paper 3 is equal to or greater than a predetermined thickness (S12). That is, since data relating to the paper thickness of the recording paper 3 is also input from the upper MPU 33 together with the paper feed operation command, it is checked whether the paper thickness is equal to or greater than a predetermined value. When the thickness of the recording sheet 3 is not uniform, for example, when another sheet is attached to a part of each page of the recording sheet 3, the paper thickness is the dimension of the thickest portion. .

If the thickness of the recording paper 3 is equal to or greater than the predetermined thickness (S12: YES), the platen motor control MPU 32
Calculates the number of drive steps for driving the platen drive source 15 (S13). That is, since the platen roller 2 is heavy and has a large inertial force, the platen drive source 1
Since the platen roller 2 continues to rotate due to the inertial force even when the operation of the recording head 5 is stopped, when the operation stop time of the platen drive source 15 is made coincident with the operation stop time of the paper transport drive source 7, the recording head 1, the rotation of the platen roller 2 does not stop, and the print quality deteriorates. Therefore, the operation stop time of the platen drive source 15 is set to be earlier than the operation stop time of the paper transport drive source 7. , The number of drive steps of the platen drive source 15 is calculated.

At this time, the driving time of the platen drive source 15 is set so that the time from the stop of the operation of the platen drive source 15 to the stop of the operation of the paper transport drive source 7 is inversely proportional to the thickness of the recording paper 3. The number of driving steps is calculated. That is, when the recording paper 3 is thick, the recording paper 3 is easily damaged if the platen roller 2 is stopped for a long time during the transportation. The time until the operation of the drive source 7 is stopped is shortened.

The platen motor control MPU 32
Calculates the drive speed of the platen drive source 15 (S1).
4). In other words, when the recording paper 3 is thick and the difference between the peripheral speed of the upper tractor 5 and the lower tractor 6 and the peripheral speed of the platen roller 2 is large, the recording paper 3 is easily damaged. Transport speed of the recording paper 3 by the upper tractor 5 and the lower tractor 6
The drive speed of the platen drive source 15 is calculated so as to be equal to or lower than the transport speed of the recording paper 3 and to be proportional to the paper thickness of the recording paper 3.

The platen motor control MPU 32
Starts driving the platen driving source 15 (S1).
5). That is, the supply of the drive pulse to the platen drive source 15 is started. Thereby, the platen drive source 15
The output shaft 16 is rotated, and its turning power is transmitted to the rotary shaft 13 via the pulley 17, the endless belt 18, and the pulley 14, and the platen roller 2 rotates.

Next, the platen motor control MPU 32
It is determined whether the driving of the platen driving source 15 has been completed (S16). That is, it is checked whether the platen drive source 15 has been driven by the number of steps calculated in step S13.

When the driving of the platen driving source 15 is completed (S16: YES), this routine is completed. Even if the driving of the platen driving source 15 is completed, the platen roller 2
Continues rotation due to the inertial force. At this point, since the paper transport drive source 7 is being driven and the recording paper 3 is being transported, and the recording by the recording head 1 is not being performed, Even if the platen roller 2 rotates, the print quality does not deteriorate. When the driving of the paper transport drive source 7 is completed, the platen roller 2 is settled.

If the driving of the platen driving source 15 is not completed in step S16 (S16: NO),
The process returns to step S16 to wait until the driving of the platen driving source 15 is completed.

In step S12, if the thickness of the recording paper 3 is not equal to or greater than the predetermined thickness (S12: NO), this routine ends. That is, if the sheet thickness of the recording sheet 3 is smaller than the predetermined thickness, the recording sheet 3 is not damaged without rotating the platen roller 2, so that the platen roller 2 is not rotated.

In step S11, the upper MPU 33
If the paper feed operation command has not been input from (S11:
NO), the process returns to step S11, and waits for a paper feed operation command from the upper MPU 33.

In the above-described embodiment, the operation of the paper transport drive source 7 is performed only when the required transport amount of the recording paper 3 is equal to or greater than a predetermined amount or when the thickness of the recording paper 3 is equal to or greater than the predetermined thickness. During this operation, the platen drive source 15 was operated, and the preceding deceleration amount and the drive speed of the platen drive source 15 were varied according to the required conveyance amount or the sheet thickness of the recording paper 3. Only when the amount is equal to or more than a predetermined amount or when the thickness of the recording paper 3 is equal to or more than the predetermined thickness, control that the platen drive source 15 is operated during operation of the paper conveyance drive source 7; Or the control of varying the advance deceleration amount and the drive speed of the platen drive source 15 in accordance with the required transport amount or the sheet thickness may be configured to be executed.

Further, only one of the advance deceleration amount and the driving speed of the platen drive source 15 may be varied according to the required conveyance amount or the sheet thickness of the recording paper 3. .

In the above embodiment, the electromagnetic clutch 24 is provided so as to prevent the rotation of the platen roller 2 when the paper transport drive source 7 is not operating. For platen motor control M
The rotation of the platen roller 2 may be prevented by the electromagnetic clutch 24 when the platen drive source 15 is not operating under the control of the PU 32. Further, the electromagnetic clutch 24 need not be provided.

Further, in the above embodiment, the configuration is such that the operator panel 34 can be switched to the manual control mode. However, the configuration may be such that the switching to the manual control mode cannot be performed.

[0070]

As described above, according to the present invention,
Since the presence or absence of rotation of the platen roller is switched according to the required transport amount of the recording paper and the thickness of the recording paper, or the operation of the platen drive source is stopped before the stop of the operation of the paper transport drive source, The recording paper can be prevented from being damaged without widening the gap between the recording head and the platen roller.
In addition, it is possible to prevent a deterioration in print quality due to a delay in stabilization of the platen roller due to inertial force.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a main part of an impact printer as an example of an image recording apparatus according to the present invention.

FIG. 2 is a schematic plan view of a main part of the impact printer shown in FIG.

FIG. 3 is a sectional view taken along the line AA in FIG. 2;

FIG. 4 is a schematic circuit block diagram of the impact printer shown in FIG.

5 is a flowchart for explaining a control processing procedure of a platen drive source by the platen motor control MPU shown in FIG. 4;

FIG. 6 is an explanatory diagram for explaining a relationship between a rotation operation of an output shaft of a sheet conveyance driving source and a rotation operation of an output shaft of a platen driving source.

FIG. 7 shows a platen motor control M according to another embodiment.
9 is a flowchart illustrating a control process procedure of a platen drive source by a PU.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording head 2 Platen roller 3 Recording paper 5 Upper tractor 6 Lower tractor 7 Paper transport drive source 8 Endless belt 15 Platen drive source 24 Electromagnetic clutch 31 Paper feed motor control MPU 32 Platen motor control MPU 33 Upper MPU 34 Operator panel

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Susumu Maruo 35, Saho, Kato-gun, Hyogo (No address) Inside Fujitsu Peripheral Machinery Co., Ltd. (72) Koji Kishimoto, Inventor 35, Saho, Kato-gun, Hyogo ( (No address) Inside Fujitsu Peripherals Co., Ltd. (56) References JP-A-7-266639 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B65H 23/188 B41J 11/00

Claims (8)

(57) [Claims] 1. An image recording apparatus comprising: a recording head; a platen roller; and transport means for intermittently transporting a predetermined amount of recording paper in a predetermined direction, wherein the transport means drives the transport means. A driving source for a platen that rotationally drives the platen roller; Activating the platen drive source during operation of the drive source, and when the required transport amount of the recording paper is less than a predetermined amount, or when the recording paper thickness is less than a predetermined thickness, the paper transport An image recording apparatus, comprising: a platen drive source control unit for stopping the platen drive source during operation of the drive source. 2. The platen drive source control means, when operating the platen drive source, stops the operation of the platen drive source prior to the stop of the operation of the sheet transport drive source. The image recording device according to claim 1. 3. An image recording apparatus comprising: a recording head; a platen roller; and conveyance means for intermittently conveying a recording sheet by a predetermined amount in a predetermined direction, wherein a paper conveyance drive source for driving the conveyance means. A driving source for the platen that rotationally drives the platen roller; and starting the operation of the driving source for the platen by starting the operation of the driving source for the sheet conveyance, before the operation stop time of the driving source for the sheet conveyance. An image recording apparatus comprising: a platen drive source control unit that stops the operation of the platen drive source. 4. The apparatus according to claim 1, wherein the platen drive source control means determines whether a time period from the stop of the operation of the platen drive source to the stop of the operation of the paper transport drive source is proportional to a required transport amount of the recording paper. 4. The image recording apparatus according to claim 2, wherein the platen driving source is controlled so as to be in inverse proportion to the thickness of the recording sheet. 5. The platen drive source control means, wherein the conveyance speed of the recording paper by the platen roller is equal to or less than the conveyance speed of the recording paper by the conveyance means, and the required conveyance amount of the recording paper or the recording The image recording apparatus according to claim 2, wherein the platen drive source is controlled so as to be proportional to a sheet thickness of the sheet. 6. The image recording apparatus according to claim 1, further comprising a lock unit that prevents the rotation of the platen roller when the paper transport drive source is not operating. 7. The image recording apparatus according to claim 1, further comprising a lock unit that prevents rotation of the platen roller when the platen drive source is not operating. 8. A forcible control unit for prohibiting a control operation by the platen drive source control unit based on an instruction operation by a user and controlling an operation of the platen drive source according to the instruction operation. An image recording apparatus according to any one of claims 1 to 7.