Patent Application
20130257949
The present invention relates to an ink-jet recording apparatus to successively ejecting particulate ink from a nozzle and a printing control method thereof.
As a background art of this technical field, there is JP-A-6-305125 (Patent Literature 1). This publication discloses that a panel for inputting a unit movement amount of an encoder, a width of a printing object and a writing start position, and a panel interface circuit are provided, and a battery backup RAM stores the unit movement amount of the encoder, the width of the printing object and the writing start position, and software calculates the unit movement amount of the encoder (see Abstract).
For example, in the related art ink-jet recording apparatus disclosed in Patent Literature 1, when a printing writing start position (position where a charged particle in the first printing scan impacts a printing object) is adjusted, the writing start position is adjusted by performing control to calculate moving speed from a previously inputted length of the printing object and a time in which the printing object passes through a sensor or by performing control to use an apparatus for generating a pulse with a frequency synchronizing with the moving speed of the printing object and to generate the pulse so that the width of a character becomes constant.
In the adjustment of the writing start position, the control is performed not only to a period from the pulse generation to the printing start timing (timing when a charging voltage is applied to the charged particle in the first printing scan), but also to a movement amount of the printing object during a period from the charging voltage application to the impact of the ink particle on the printing object. However, in the adjustment of the writing start position at this time, consideration is given to only a case where the moving speed is constant, and consideration is not given to a shift caused by acceleration or deceleration.
One of problems due to the change of the moving speed of the printing object is the shift of the printing writing start position, and there is a problem that the printing writing start position shifts backward when the moving speed is high as compared with the case where the moving speed is low.
In the related art, it is assumed that the moving speed of the printing object is constant. Thus, after the moving speed is calculated from the length of the printing object and the light-shielding time of the sensor, a line clock signal is generated based on only the moving speed, and the writing start position control is performed.
Thus, the line clock signal is generated based on only the speed at the time of measurement of the sensor, and a change in the writing start position due to a change in the moving speed between the sensor and the printing position after the generation of the line clock signal can not be dealt with, and the writing start position of a printing part is shifted.
An object of the invention is to provide an ink-jet recording apparatus and a printing control method, in which even when a moving speed of a printing object is accelerated or decelerated, a difference in writing start position is reduced and printing quality is improved.
In order to solve the problem, for example, the structure recited in the claims is adopted.
This application includes plural means for solving the problem and one example is such that an ink-jet recording apparatus includes an ink container to contain ink for printing a printing object, a nozzle that is connected to the ink container and ejects the ink, a charging electrode to charge the ink ejected from the nozzle and used for printing, a deflecting electrode to deflect the ink charged by the charging electrode, a gutter to collect ink not used for printing, a writing start timing control circuit to generate a first line clock signal, a printing width control circuit to generate a second line clock signal, and a control part, wherein the control part controls a writing start position to the printing object based on the first line clock signal, and when the printing object reaches a printing start timing, the control part adjusts a width of a character string of printing content based on the second line clock signal and performs printing control.
According to the invention, the ink-jet recording apparatus and the printing control method can be provided in which even when a moving speed is changed before a printing object reaches a printing position after passing through a sensor, a shift in printing writing start position can be reduced, and printing quality can be improved.
Hereinafter, embodiments will be described with reference to the drawings.
A writing start timer 106 includes a counter and adjusts the timing of printing start. A printing control circuit 107 controls a printing operation of the ink-jet recording apparatus. A printing object detection circuit 108 detects a printing object. A moving speed measuring circuit 109 calculates a moving speed from the detection time of the printing object and the inputted length of the printing object. A writing start timing control circuit 120 generates a line clock signal for determining the timing of sending a character signal at the time of writing start from the measured moving speed. A printing width control circuit 121 generates a line clock signal for controlling so that the width of the printing character string becomes constant. A character signal generating circuit 110 converts the printing content into the character signal.
A bus line 111 sends data and the like, and a nozzle 112 ejects ink. A charging electrode 113 applies an electric charge to an ink particle formed of ink ejected from the nozzle. A deflecting electrode 114 deflects the charged ink particle. A gutter 115 collects ink not used for printing. A pump 116 again supplies the ink collected by the gutter to the nozzle. Sensors 117 and 122 detect a printing object. A printing object 118 is an object of printing, and a conveyor 119 conveys the printing object.
Next, a description will be made on the outline of a series of operations from the input of printing content to the completion of printing.
The printing content can be set in such a way that printing content data is inputted by the panel 105 and is stored in the RAM 102. Besides, a distance between vertical lines (movement distance per one pulse of a line clock signal) is determined from the width of a printing character string set by the panel 105 and is stored in the RAM 102.
A moving speed calculation program stored in the ROM 103 calculates the maximum printing speed of the printing content from the printing content set by the panel 105, a printing format and the distance between the vertical lines. Control is performed to align positions on the basis of a writing start position determined by the line clock signal generated with the maximum printing speed.
Here, the line clock signal will be described with reference to
The line clock signal corresponds to a signal obtained in such a way that in a signal generating apparatus 201, such as a rotary encoder, for performing speed control in synchronization with the movement amount of a printing object, an external pulse is inputted to the apparatus by an input circuit 202, and the inputted external pulse is divided by a divider circuit 203.
When the signal generating apparatus is used, a timing when a character signal is generated is adjusted based on the divided signal, and printing is performed. A character signal shown in
Printing control and writing start position control are performed so that the period of the line clock signal becomes a movement time per one scan, and becomes the length of an inputted printing character string. The moving speed of a printing object is known from the scan interval (period of the pulse) of the line clock signal. As shown in
The line clock signal is generated as described below. First, when the printing object detection sensor 117 detects a printing object as a control object, the printing object detection circuit 108 measures a light-shielding time of the printing object. The moving speed measuring circuit 109 measures the moving speed of the printing object based on the length of the printing object set by the panel 105 and the measured light-shielding time.
Next, the line clock signal is generated based on the ratio of the moving speed of the printing object to the maximum printing speed determined at the time of setting. The generated line clock signal is stored in the RAM 102 through the bus line 111.
The number (1) of line clock pulses required from the printing object detection sensor 117 to the writing start can be calculated by dividing the distance from the printing object detection sensor 117 to the writing start by the stored distance between the vertical lines.
Besides, the movement amount of the printing object from the generation of the character signal generated by the character signal generating circuit 110 to the impact of the writing start particle to the printing object is calculated from the particle flying time obtained from the printing distance inputted by the panel 105 and the measured moving speed. The number (2) of line clock pulses is calculated by dividing the movement amount by the distance between the vertical lines.
The sum of the numbers (1) and (2) of the line clock pulses is made a counter value when the writing start timer 105 counts the number of pulses. The writing start timer 106 starts countdown from the counter value one by one in response to each pulse of the line clock signal. When the counter of the writing start timer 106 ends counting, a time-up instruction reaches the MPU 101 from the writing start timer 106.
When receiving the time-up instruction, the MPU 101 generates an instruction of printing start timing, and the MPU 101 sends the printing content stored in the RAM 102 to the character signal generating circuit 110 through the bus line 112.
The character signal generating circuit 110 converts the sent printing content into a character signal, and the charging electrode 113 applies a charging voltage corresponding to the character signal to ink particles formed of ink ejected from the nozzle 112.
The printing control circuit 107 controls the timing when the charging signal for performing the application control of the charging voltage is sent to the charging electrode 113 through the bus line 111. The ink particle charged by this control is deflected by the deflecting electrode 114, flies to the printing object 118 conveyed by the conveyor 119, and is adhered so that printing is performed. Ink particles not used for printing are collected by the gutter 115, and are again supplied to the nozzle 112 by the pump 116.
A difference between the related art and the invention at the time of generation of a line clock signal will be described with reference to
The printing object 118 is conveyed as shown in
First, the related art will be described, while generation of line clock signals from passing of the printing object 118a through the printing object detection sensor 117 to completion of printing of the printing object 118b is shown in
First, a line clock signal S1 is generated which corresponds to a moving speed V1 obtained from a measurement time when the printing object 118a passes through the printing object detection sensor 117. The printing object 118a is operated by the line clock signal S1 after the measurement of the printing object detection sensor 117 until the completion of printing.
Next, a line clock signal S2 is generated which corresponds to a moving speed V2 obtained from a measurement time when the printing object 118b separated from the printing object 118a by a specific distance and conveyed thereafter passes through the printing object detection sensor 117. The printing object 118b is operated by the line clock signal S2 after the measurement of the printing object detection sensor 117 until the completion of printing.
Line clock signal generation methods of the printing object 118a and the printing object 118b are the same, and a line clock signal for a printing object 118 conveyed after the printing object 118b is also generated by the same method.
At this time, in the related art, when the writing start position of the printing object 118a is calculated, the line clock signal is generated by using only the data measured when the printing object 118a passes through the printing object detection sensor 117. Thus, when the printing object 118a is accelerated or decelerated during the movement from the timing when the printing object passes through the printing object detection sensor 117 to the timing of printing start, the writing start position can not be adjusted. Accordingly, there is a problem that if the moving speed of the printing object is accelerated or decelerated, a shift occurs in the writing start position, and the printing quality is reduced. Similarly, also after the printing object 118b, the problem occurs if the moving speed of the corresponding printing object is accelerated or decelerated.
Next, the line clock signal generation of the invention will be described. Plural moving speed data stored in the RAM 102 are sent to the writing start timing control circuit 120 through the bus line 111, and the moving speed is calculated in view of acceleration.
The data of the line clock signal generated in response to the moving speed is set in the writing start timer 106 through the bus line 111. Hereinafter, the control of the writing start timing control circuit 120 in view of the acceleration will be described.
First, printing content and a printing condition are set (S1), and a maximum printing speed is calculated from the set values (S2). A first moving speed V1 and a second moving speed V2 of a printing object are calculated by an after-mentioned method (S3, S4), and an average moving speed V12 and an acceleration “a” are obtained based on the first and second moving speeds (S5). By this, a first line clock signal is generated from the ratio of the average moving speed V12 to the maximum printing speed (S6). The number of line clock pulses is calculated based on the first line clock signal, and is made a set value of a timer to count pulses (S7).
Further, a moving speed V3 at a point of printing start to the printing object is calculated from the acceleration “a” (S8), and a second line clock signal is generated from the ratio of the moving speed V3 to the maximum printing speed (S9). The time when the pulse count of the timer reaches the set number of line clock pulses is made a printing start timing, and printing is started in accordance with the second line clock signal (S10).
With respect to the calculation of the acceleration of the printing object in the flowchart of
First, a case where the acceleration is obtained from moving speeds of two printing objects will be described. In this case, as shown in
Since the acceleration of the first moving printing object 118a can not be calculated, a line clock signal for the printing object 118a is generated based on only the moving speed V1 obtained from the measurement time for passing through the printing object detection sensor 117. The printing object 118a is operated by the line clock signal S1 after the measurement of the printing object detection sensor 117 to the completion of printing.
Next, with respect to the printing object 118b, the acceleration is considered. Here, since moving speeds of two printing objects are required in order to obtain the acceleration, the moving speed V1 and the moving speed V2 of the printing object 118a and the printing object 118b at the time point of passing through the printing object detection sensor 117 are calculated. Here, the line clock signal generated based on the moving speed V1 is made S1. The acceleration of the printing object 118b is calculated from the moving speeds of the two printing objects and a time difference between the measurement times of the two printing objects measured by the printing object detection sensor from the position information of the printing object detection sensor detected by the printing object detection circuit 108.
Next, a moving speed V2′ of the printing object 118b at the printing position can be calculated from the calculated acceleration and the moving speed V2 of the printing object 118b. An average speed V2″ between the printing object detection sensor 117 and the printing position is calculated from the speed V2 at the position of the printing object detection sensor and the speed V2′ at the printing position. The writing start timing control circuit 120 generates a line clock signal S2 from the ratio of the average speed V2″ to the maximum printing speed to enable printing with the printing content (determined width of a printing character string).
In order to suppress the change of the writing start position, the line clock signal S2 is set in the writing start timer 106 until the printing object 118b moves to the printing position from the printing object detection sensor 117. When the counter ends counting, a writing start timer time-up instruction reaches the MPU 101. When the instruction reaches, the period is changed to that of a line clock signal S2′, and control is performed from printing start to printing completion so that the change of the width of a printing character string is suppressed.
With respect to a printing object 118 conveyed after the printing object 118b, similarly to the printing object 118b, the acceleration is calculated from the moving speed of the former printing object, and a line clock signal capable of dealing with the acceleration or deceleration can be generated.
Next, a case where two sensors are used and acceleration is obtained from moving speed of a printing object will be described with reference to
In this case, as shown in
Next, a moving speed V1′ of the printing object 118a at the printing position is calculated from the calculated acceleration. The printing width control circuit 121 generates a line clock signal S1′ from the ratio of the moving speed V1′ at the printing position to the maximum printing speed in the printing content.
An average speed V1″ is calculated from the speed V1 at the sensor position and the speed V1′ at the printing position. The writing start timing control circuit 120 generates a line clock signal S1 from the ratio of the average speed V1″ to the maximum speed in the printing content. In order to suppress the change in the writing start position, the line clock signal S1 is set in the writing start timer 106 until the printing object 118a moves to the printing position from the printing object detection sensor 122. When the counter ends counting, a writing start timer time-up instruction reaches the MPU 101. When the instruction reaches, the period is changed to that of a line clock signal S1′, and control is performed from printing start to printing completion so that the change of the width of a printing character string is suppressed.
With respect to a printing object 118 conveyed after the printing object 118a, similarly to the printing object 118a, the acceleration is calculated from moving speeds of the printing object obtained by the two sensors, and a line clock signal in view of the acceleration can be generated.
According to the above embodiment, the ink-jet recording apparatus can be provided in which even when the printing object is accelerated or decelerated, printing can be performed while a shift in writing start position is suppressed, and printing quality can be improved.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-078876 | Mar 2012 | JP | national |
