JPH06211398A - Printer - Google Patents

Abstract

PURPOSE:To prevent printing from being put out of order by providing a means for detecting a sagging amount of paper, and controlling a paper conveying speed synchronized with this sagging amount, so as to absorb a load fluctuation in an original roll side while maintaining the sagging amount. CONSTITUTION:In peripheral speeds of rollers 9, 3, the peripheral speed in a side of the roller 3 is set to a slow condition, to generate a direction of tensing paper when started conveyance. A sensor 8 is set so as to be off when a sagging amount is decreased from a certain set value. When the sensor 8 is turned off, a motor 4 is converted to the second speed and driven by a signal of the sensor. In the second speed, the peripheral speed of the roller 3 is set a little faster relating to the peripheral speed of the roller 9. By driving at the second speed, the sagging amount of paper is increased, to place the sensor in an on-condition. Based on this signal, the peripheral speed of the roller 3 is switched to a speed slower than the peripheral speed of the roller 9, and thereafter based on on/off signals of the sensor 8, the speed is repeatedly switched.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus which conveys a sheet and prints and records it.

[0002]

2. Description of the Related Art Conventionally, a printing apparatus which conveys a sheet for printing is usually constructed so that a constant back tension is applied to the sheet to convey the sheet while pulling the sheet. There is.

[0003]

However, in the above-mentioned conventional example, since the paper is conveyed while being pulled, when the load is applied to the paper from the outside, the print portion is directly affected and the print paper vibrates. However, there is a defect that the printing is disturbed or the printing quality is deteriorated by giving the above.

Therefore, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a printing apparatus capable of reducing the load fluctuation applied to a sheet and performing good printing.

[0005]

According to the printing apparatus of the present invention, the means for controlling the sheet conveying speed on the printing section side and the sheet conveying speed on the original side separately, and the slack amount of the sheet at that time are detected. By providing a means for controlling the sheet conveyance speed in synchronism with the slack amount, the sheet can be conveyed while always maintaining the slack amount within a certain range to reduce the load fluctuation on the original side. It absorbs and prevents the disturbance of printing.

[0006]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 4 shows an example of a printing apparatus to which the present invention can be applied. The printing apparatus shown in the figure prints on a roll-shaped paper 1 such as a continuous label. When the paper is conveyed, the roll-shaped paper is more likely to cause load fluctuations than the standard-sized paper, and therefore, the present invention is not limited to this. Suitable for implementation.

Characters, images, bar codes and the like are examples of characters printed by the printer.

The roll-shaped paper 1 is conveyed to the printing section by the conveyance roller 47, the main roller 48 and the belt 50, and printed by the print head 41. After the roll-shaped paper 1 is printed, it is ejected from the paper ejection port 49 by the paper ejection roller 14.

The print head 41 is composed of four color ink jet heads of Y, M, C and Bk, and ink of each color is supplied from an ink supply system 42. Reference numeral 43 is a recovery system device for performing recovery work of the print head. The head of each color is a full multi-type head capable of printing the width of the roll-shaped paper, and the recovery system 43 is provided with capping means and suction means corresponding to the head of each color. Examples of the inkjet recording method include so-called on-demand type and continuous type. As the print head 41 shown in FIG. 4, a head of a method that ejects ink by utilizing thermal energy, which is capable of high-speed recording among inkjet recording methods, is applied.

Reference numeral 44 is a host computer for sending image data signals and the like to the printer, 45 is a memory card for recording the print format and print contents, and 46 is a CPU for controlling printing.

Next, a first embodiment of the present invention will be described with reference to FIG.

(Embodiment 1) FIG. 1 is a drawing showing an embodiment of the present invention, and shows in detail the paper conveying system of the printing apparatus shown in FIG. In FIG. 1, 1 is a roll-shaped paper and 2 is a holding member for holding the roll-shaped paper 1. Reference numeral 3 denotes a roller that controls the amount of slack of the roll-shaped paper 1 that is conveyed, and is driven by a drive motor 4 via a timing belt 5. Further, 6 is a loop plate that operates according to the amount of slack of the sheet, 7 is a support shaft of the loop plate 6, and 8 that is close to the loop plate 6 is a sensor that detects the movement of the loop plate.

Reference numeral 9 is a main roller for controlling the sheet conveying speed in the printing section, 14 is a sheet ejection roller for ejecting the sheet to the outside of the apparatus, and the roller of the printing section is driven by a drive motor 13 via a timing belt 15. Driven. Also,
10 is a TOF (Top of F) that detects the position of the paper.
orm) sensor. Reference numeral 11 is a print head for performing print recording on the conveyed paper, and 12 is a platen. Further, 17 is a power supply for supplying electricity to each unit, and 18 is a controller for controlling each unit actuator.

FIG. 2 shows the loop plate 6 and the sensor 8 of this embodiment.
It is a drawing of the portion of FIG. 6A, the loop plate 6 is provided with a flag 6a, and an arc-shaped oblong hole as shown in the figure is formed in the portion of the 6a that interrupts the sensor 8. The position is set so that the inside is in the sensor section within the range of the appropriate amount of slack.

Next, the operation of the printer will be described.

When the power is turned on and the print command is transmitted, the state of the sensor 8 is checked. The sensor 8 is turned on when the sheet has a certain slack and turned off when the sheet is stretched. If the sensor 8 is off, the motor 4 is driven until the sensor 8 is turned on to ensure a certain slack.

Next, the motor 13 and the motor 4 are driven at the same time. At this time, the peripheral speed of the roller 9 and the peripheral speed of the roller 3 are set to be slow on the roller 3 side, and the sheet is stretched when the conveyance is started. Direction. The sensor 8 is set to be turned off when the amount of sag becomes less than a set value. When the sensor 8 is turned off, the signal causes the motor 4 to be converted into the second speed and driven. The second speed is set so that the peripheral speed of the roller 3 is slightly higher than the peripheral speed of the roller 9. By driving at the second speed, the amount of slack of the paper increases, and the sensor 8 is turned on. Then, based on this signal, the peripheral speed of the roller 3 is switched to a speed lower than the peripheral speed of the roller 9, and thereafter,
The speed switching described above is repeated based on the ON and OFF signals of the sensor 8.

On the other hand, as the paper is conveyed, the TOF sensor 1
0 conveys information on the leading edge position of the paper to the controller 18,
Based on the information, the controller 18 gives a print command to the print head 11 to perform print recording.

With the above construction, even when a constant tension is applied to the paper being conveyed and the load is changed on the roll-shaped paper, the change is absorbed by the loop plate, and the disturbance of printing due to the influence of the load change is prevented. be able to.

(Embodiment 2) FIG. 3 shows a mechanism portion for detecting the amount of slack in another embodiment. In the previous embodiment, the sensor 8 is controlled by two values of ON and OFF. As shown in FIG. 3, the loop plate 6 is provided with a flag 6b and the sensor 8a,
The same effect can be obtained by arranging so as to be 8b and controlling four values.

(Other Embodiments) The printing method applied to the printing apparatus of the present invention is also applicable to the heat sensitive method and the dot impact method, but the ink jet recording method shown in the embodiment does not contact the paper. Since it is a non-impact method and is more easily affected by fluctuations in sheet conveyance than other printing methods, it is suitable for implementing the present invention.

[0023]

As described above, since a certain amount of slack is secured in the sheet during conveyance of the sheet, when a load variation occurs on the roll-shaped sheet or the like, the variation is absorbed by the amount of the slack. Since the influence of the load fluctuation is not directly transmitted to the printing unit, it is possible to prevent the occurrence of printing irregularity or unevenness. Moreover, since the amount of slack is changed by switching the drive of the sensor and the motor, a certain amount of slack can be secured promptly.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating details of a loop plate.

FIG. 3 is a diagram illustrating a second embodiment.

FIG. 4 is a diagram illustrating an example of a printer to which the present invention is applicable.

[Explanation of symbols]

 1 Rolled Paper 2 Rolled Paper Holding Member 3 Control Roller 4 Motor 5 Timing Belt 6 Loop Plate 7 Spindle 8 Sensor 9 Main Roller 10 TOF Sensor 11 Print Head 12 Platen 13 Motor

Claims (1)

[Claims] 1. A paper feed mechanism for feeding a print paper, a paper discharge means provided on the feed direction side of the paper feed mechanism, and a rotatable mechanism within a certain range between the paper feed mechanism and the paper transport means. A sheet tensioning unit that is provided to apply a tension to the sheet fed by the sheet feeding mechanism, a sensor unit that detects a rotating state of the sheet tensioning unit, and a position between the sheet tensioning unit and the sheet ejection unit. An image forming means for forming an image on a printing paper, a speed changing means for changing the paper feeding speed of the paper feeding mechanism, and a sensor means for changing the paper feeding speed by the speed changing means.