JP2017001283A - Printer, control method and control program thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printer which improves resolution and the printing speed by reducing the occurrence of unnecessary radiation noise and signal delay.SOLUTION: A sublimation type printer includes a recording head 2 which has a plurality of heating resistors and performs printing on a printing sheet by heating the recording head 2. The heating resistors are divided into plural groups. A driver IC 411 is provided in each group and heats the heating resistor with conduction data 331 indicating a conduction pattern in accordance with a clock signal 341 transmitted from a head control ASIC 3 controlling the recording head 2. The recording head 2 sequentially operates the driver IC 411 in accordance with a data enable signal 321 transmitted from the head control ASIC 3, and transmits the conduction data 331 in accordance with the image data transmitted from the head control ASIC 3 to the driver IC 411.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a printing apparatus, a control method thereof, and a control program, and more particularly to a sublimation type printing apparatus.

  2. Description of the Related Art In recent years, with the advancement of imaging devices such as digital cameras or digital video cameras, and image input devices such as scanners, sublimation printing devices (hereinafter referred to as sublimation printers) have attracted attention as printing devices for printing images. ing.

  In a sublimation printer, thermal paper is used as printing paper, and a plurality of heating elements (thermal heads) arranged in the main scanning direction of an image are selectively driven. Then, by carrying the printing paper in the sub-scanning direction, dot-line printing is performed on the printing paper.

  By the way, when printing an image such as a photograph, the photograph is printed one by one. On the other hand, for example, it is also printed together for each event to form a booklet. The printing at the time of making this booklet is called photobook printing. The number of users who perform photobook printing is increasing. Photobook printing is attracting attention as a new method for using a sublimation printer.

  Since photobooks are often premised on distribution to acquaintances and the like, users demand high print quality for photobook printing. Accordingly, in photobook printing, higher image quality and higher resolution will be required in the future, and it is necessary to improve the finished quality.

  High resolution in the sublimation printer is performed by increasing the number of heat generating resistor portions arranged in the main scanning direction in the thermal head. Each of the heat generating resistor units is controlled by, for example, a driver IC. Since the sublimation printer performs printing by line scanning, a predetermined number of heating resistors are controlled by one driver IC, as will be described later.

  For this reason, if the number of heating resistor portions is increased in order to increase the resolution, the number of driver ICs inevitably increases. An increase in the driver IC leads to an increase in the signal lines (control lines) of the head control IC that controls the driver IC. Such an increase in the number of signal lines causes generation of unnecessary radiation noise and generation of signal delay due to wiring, which becomes an obstacle when performing printing using a sublimation printer.

  Further, the signal delay causes a shift in the latch timing of the print data in the thermal head, resulting in image quality deterioration such as a color shift and a color cast.

  On the other hand, in some sublimation printers, for example, the voltage application of the heating resistor unit is controlled by a switching element based on data held in a latch (see Patent Document 1). In addition, there is one in which switching time of the switching element is controlled by a multi-pulse to control the energization time of the heating resistor portion (see Patent Document 2).

JP-A-6-71924 JP-A-6-246953

  As described above, it is necessary to reduce the increase in the number of control lines due to the high resolution in the sublimation printer. In the printer described in Patent Document 1, control lines such as latches can be reduced.

  However, in the printer described in Patent Document 1, the number of address lines increases in proportion to the number of driver ICs because the driver ICs are controlled by the address lines. As a result, in the printer described in Patent Document 1, unnecessary radiation noise and signal delay as described above occur.

  In the printer described in Patent Document 2, driver ICs are simply cascade-connected. For this reason, when transferring one line of print data, the data passes through a shift register provided in the driver IC.

  Therefore, in the printer described in Patent Document 2, it is difficult to improve the transfer speed of print data. In consideration of the fact that sublimation printers are required to improve the resolution and speed of printing, it is difficult for the printer described in Patent Document 2 to improve the printing speed.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a printing apparatus, a control method thereof, and a control program capable of reducing the generation of unnecessary radiation noise and signal delay, increasing the resolution and improving the printing speed. is there.

  In order to achieve the above object, a printing apparatus according to the present invention is a printing apparatus that has a recording head including a plurality of heating resistors, and generates heat on the printing paper by generating heat from the recording head. The body is divided into a plurality of groups, and a driver is provided for each of the groups, and generates heat with the energization data indicating the energization pattern in accordance with a clock signal sent from a control means for controlling the recording head. And transfer means for sequentially operating the driver means in response to a data enable signal sent from the control means and sending the energization data corresponding to image data sent from the control means to the driver means. It is characterized by that.

  A control method according to the present invention is a control method of a printing apparatus that has a recording head including a plurality of heating resistors, and heats the recording head to print on printing paper, wherein the heating resistors are in a plurality of groups. In accordance with a data enable signal sent from a control unit that controls the recording head, a driver provided in each of the groups is sequentially operated, and according to image data sent from the control means. A first step of sending energization data indicating an energization pattern to the driver, and a second step of causing the heating resistor to generate heat with the energization data in accordance with a clock signal sent from the control means by the driver. It is characterized by that.

  A control program according to the present invention is a control program that is used in a printing apparatus that has a recording head including a plurality of heating resistors and generates heat on the recording paper by generating heat from the recording head. The computers provided in the printing apparatus are sequentially operated by a driver provided in each of the groups in response to a data enable signal sent from a control unit that controls the recording head. A first step of sending energization data indicating an energization pattern according to data to the driver, and a second step of causing the heating resistor to generate heat with the energization data in response to a clock signal sent from the control unit by the driver. Are executed.

  According to the present invention, the driver means is sequentially operated according to the data enable signal sent from the control means, and the energization data corresponding to the image data sent from the control means is sent to the driver means. As a result, even if the number of driver means increases as the resolution of the recording head increases, the recording head can be controlled without increasing the number of control lines.

  Furthermore, since the energization data is sequentially transferred to the driver means corresponding to the group of heat generating resistors that generate heat, the recording head can be controlled without decreasing the printing speed. As a result, generation of unnecessary radiation noise and signal delay can be reduced, so that high resolution can be achieved and the printing speed can be improved.

It is a figure for demonstrating an example of the printing (it is also called a printing) by a sublimation type printer. FIG. 2 is a diagram illustrating an example of a configuration of a recording head illustrated in FIG. 1 and a connection with a head control ASIC. FIG. 3 is a block diagram showing an example of the configuration of the driver IC shown in FIG. 2. 3 is a time chart of data, a latch signal, and a clock transferred from the head control ASIC shown in FIG. 2 to a recording head. 1 is a block diagram illustrating a configuration of a sublimation printer that is an example of a printing apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating an example of the configuration of the recording head illustrated in FIG. 1. 7 is a timing chart for explaining operations of the recording head and the head control ASIC shown in FIG. 6.

  Hereinafter, an example of a printing apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  Here, a so-called sublimation printer will be described as an example of a printing apparatus according to an embodiment of the present invention. Before describing a sublimation printer according to an embodiment of the present invention, printing using a sublimation printer will be described in order to facilitate understanding of the sublimation printer.

  FIG. 1 is a diagram for explaining an example of printing (also called printing) by a sublimation printer.

  The illustrated sublimation printer has an SDRAM 42, and print image data 41 is developed on the SDRAM 42. The CPU 43 corrects the printing image data 41 by performing predetermined image processing on the printing image data expanded on the SDRAM 42. Then, the CPU 43 sends the corrected printing image data to the head control ASIC 44.

  The head control ASIC 44 generates an energization pattern signal for controlling the recording head 45 based on the corrected printing image data. The recording head 45 performs energization control with respect to the thermal head (that is, the heating resistor portion) according to the energization pattern signal. As a result, the recording head 45 prints the printed matter 46 corresponding to the printing image data on the printing paper.

  FIG. 2 is a diagram showing an example of the configuration of the recording head 45 shown in FIG. 1 and the connection with the head control ASIC 44.

  The recording head 45 includes a heating resistor portion (thermal head) 53 and a plurality of driver ICs 52. The heating resistor portion 53 has a plurality of heating resistors. In the illustrated example, ten driver ICs 52 are provided, and a predetermined number of heating resistors are connected to each of the driver ICs 52. That is, the heating resistors are divided into a plurality of groups.

  In the following description, the lowermost driver IC 52 in FIG. 2 is referred to as a first driver IC 52, and the uppermost driver IC 52 is referred to as a tenth driver IC 52.

  The head control ASIC 44 decodes the corrected printing image data received from the CPU 43 shown in FIG. 1, and generates an energization pattern signal that is a recording head signal. Each of the driver ICs 52 is connected to the head control ASIC 44 by three signal lines including a data line, a latch line, and a clock line. The head control ASIC 44 controls the driver IC 52 with these three signal lines.

  That is, the energization pattern signal has print data, a latch signal, and a clock. The head control ASIC 44 sends print data (hereinafter also simply referred to as data), a latch signal, and a clock signal (hereinafter simply referred to as a clock) to the driver IC 52 via the data line, the latch line, and the clock line, respectively. Then, the driver IC 52 controls energization of the heat generating resistor of the heat generating resistor portion 53 according to the printing data as described later.

  FIG. 3 is a block diagram showing an example of the configuration of the driver IC 52 shown in FIG.

  The driver IC 52 has the same number of shift registers 62 as the number of heating resistors connected to the driver IC 52. These shift registers 62 are each connected to a heating resistor.

  As shown in the figure, a latch signal 64 and a clock 65 are applied to each shift register 62. Further, data 63 is supplied from the head control ASIC 44 to the shift register 62 located at the uppermost position in the drawing.

  FIG. 4 is a time chart of data, latch signals, and clocks transferred from the head control ASIC 44 shown in FIG. 2 to the recording head 45.

  Referring to FIGS. 3 and 4, head control ASIC 44 sends data 63 indicating the energization pattern signal to shift register 62 located on the uppermost side in the drawing in synchronization with clock 65 having a predetermined period. Then, the shift register 62 latches the data 63 according to the latch signal, shifts the data 63 according to the clock, and outputs it as the first head data 66.

  The first head data, which is the output of the shift register 62 located at the uppermost position in the drawing, is sent to the next shift register 62, and the next shift register latches the first head data according to the latch signal. The next shift register shifts the first head data according to the clock and outputs it as the second head data. Then, the second head data is given to the third shift register 62.

  In this way, the head data which is the output of the previous shift register 62 is given to the shift register 62 located on the lowermost side in the drawing. The shift register 62 located on the lowermost side in the figure latches the head data and outputs it as its own head data.

  The head data that is output from the shift register 62 is output to the heating resistor of the heating resistor 53, and these heating resistors generate heat when the head data is ON (H level).

  Referring again to FIG. 2, printing is generally performed by line scanning in a sublimation printer. The recording head 45 includes a plurality of driver ICs 52 (10 in the example shown in FIG. 2), and these driver ICs 52 perform heat generation control of the heat generation resistor unit 53.

  For example, in the case of the recording head 45 having a 4-inch 1280-dot heating resistor, one driver IC 52 is assigned to 128 heating resistors, and this driver IC 52 performs ON / OFF control of the heating resistors. Do.

  In the configuration shown in FIG. 2, the number of driver ICs 52 inevitably increases as the number of heating resistors provided in the heating resistor unit 53 increases. As the number of driver ICs 52 increases, the number of signal lines connecting the head control ASIC 44 and the recording head 45 increases.

  When the number of signal lines increases, not only unnecessary radiation noise is generated, but also signal delay occurs. The signal delay may cause a shift in data latch timing in the recording head, resulting in image quality deterioration such as color shift and color cast.

  FIG. 5 is a block diagram illustrating a configuration of a sublimation printer that is an example of a printing apparatus according to an embodiment of the present invention.

  The illustrated sublimation printer (hereinafter simply referred to as a printer) has a CPU 4. The CPU 4 controls the entire printer and performs various arithmetic processes. The image processing unit 5 includes an image processing engine and the like.

  The image processing unit 5 performs predetermined image processing on image data sent from a camera (not shown) or image data acquired from an SD card (SD memory card). For example, the image processing unit 5 performs image processing such as decompression on the image data acquired as described above to generate image data for printing.

  A flash ROM (FLASH ROM) 9 stores a printer control program. Image data is temporarily stored in the SDRAM 10, and the SDRAM 10 is used as a working memory for the CPU 4. Image data is stored as a data file in the SD card 11 as a recording medium.

  The SD card 11 is attached to the printer by a card connector 12. The LCD 13 displays a photographed image corresponding to image data obtained as a result of photographing by the camera, and an operation menu and the like. The LCD driver 14 drives the LCD 13 under the control of the CPU 4.

  The communication control unit 6 controls communication with an external device. For example, the communication control unit 6 controls communication with a camera connected to the printer. The operation unit 7 receives an instruction input from the user. A head control ASIC (thermal head control unit) 3 controls the recording head 2 under the control of the CPU 4 to perform printing on the printing paper in accordance with the printing image data.

  That is, the head control ASIC 3 generates an electrical signal (energization pattern signal) corresponding to the image data for printing that is an output of the image processing unit 5, and outputs the electrical signal to the recording head 2. Then, the recording head 2 performs printing on the printing paper by converting the electric signal into heat energy.

  The environmental temperature sensor 1 measures the environmental temperature around the printer. The head temperature sensor 8 measures the temperature of the recording head 2. Further, the ink ribbon remaining amount meter 15 is provided in the printer and detects the remaining amount of the ink ribbon for printing.

FIG. 6 is a block diagram showing an example of the configuration of the recording head 2 shown in FIG.
FIG. 7 is a timing chart for explaining operations of the recording head 2 and the head control ASIC 3 shown in FIG.

  In the example shown in the figure, it is assumed that the heat generating resistor 421 has a total of 1280 heat generating resistors along the main scanning direction (printing paper feeding direction).

  With reference to FIGS. 6 and 7, the recording head 2 includes a heating resistor 421. Further, the recording head 2 includes a driver IC 411, an interpolation circuit 401, a counter circuit 371, a selector (SEL) 351, a latch generation circuit 391, and an EN (enable signal) generation circuit 441.

  In FIG. 6, ten interpolation circuits 401 are provided. Here, the lowermost interpolation circuit 401 in the figure is the first interpolation circuit 401, and the uppermost interpolation circuit 401 is the tenth interpolation circuit 401. Similarly, ten driver ICs 411 are provided. Here, the driver IC 411 located on the lowermost side in the drawing is referred to as a first driver IC 411, and the driver IC 411 located on the uppermost side is referred to as a tenth driver IC 411.

  The head control ASIC 3 controls the recording head 2 using data 331, a data EN signal (data enable signal) 321, and a clock 341. The head control ASIC 3 receives image data from the CPU 4 (FIG. 5) via the data bus 36. The head control ASIC 3 decodes the image data to generate data 331 for the recording head 2, a data EN signal, and a clock (control signal).

  Here, it is assumed that the head control ASIC 3 sends the odd-numbered pixel and even-numbered pixel data 331 alternately to the recording head 2 for each gradation. Then, the recording head 2 energizes the heating resistor 421 in accordance with the data 331.

  By the way, in general, in a small-sized sublimation printer for consumers, so-called divided drive control is performed in the recording head 2 so as to express one gradation by alternately energizing odd and even pixels. Compared to so-called collective drive control in which energization is performed for all the pixels of the recording head 2, voltage drop during energization can be suppressed in the split drive control.

  Therefore, if the split drive control is used, the power supply unit (not shown) of the sublimation printer can be reduced in size, and the split drive control is widely used in the small sublimation printer mainly used for mobile and home use. It has been.

  Here, the recording head 2 is energized by divided drive control, and the head control ASIC 3 alternately sends data 331 for even pixels and odd pixels to the recording head 2 for each gradation.

  For example, as shown in FIG. 7, the head control ASIC 3 changes the data EN signal from the L level to the H level, and first, even pixels “0”, “2”, “4”, to, “1278”, and “1280” The data 331 is transferred to the recording head 2. Then, the head control ASIC 3 changes the data EN signal from the H level to the L level, and then changes the data EN signal from the L level to the H level again.

  As a result, the head control ASIC 3 transfers data 331 to the recording head 2 regarding the odd pixels “1”, “3”, “5”,..., “1277”, and “1279”.

  The data EN signal 321 indicates the valid period of the data 331, and the head control ASIC 3 makes the data EM signal 321 valid (that is, H level) one clock before starting the transfer of the data 331. The data EN signal 321 is used for the counter start by the counter circuit 371.

  As shown in FIG. 6, the data EN signal 431 is supplied to the SEL 351 and the counter circuit 371. The SEL 351 identifies whether the data 331 transferred from the head control ASIC 3 is for odd pixels or even pixels in synchronization with the data EN signal 431. Then, the SEL 351 outputs an odd / even identification SEL signal 431 to the counter circuit 371.

  The counter circuit 371 counts the number of data 331 transferred from the head control ASIC 3 to the recording head 2. Note that the count processing in the counter circuit 371 is performed using a clock that is doubled faster than the data 331 (doubled clock). That is, the counter circuit 371 starts counting the double clock when the data EN signal 321 becomes valid.

  The counter circuit 371 stops counting the doubled clock when the odd / even identification SEL signal is switched from odd to even or even to odd. The counter 371 outputs count signals 440 and 441 indicating the count value while the count is continued.

  The count signal 440 is sent to the latch generation circuit 391, and the count signal 441 is sent to the EN generation circuit 381. The EN generation circuit 381 generates first to tenth EN (enable) signals 451 according to the count signal 441. These first to tenth EN signals 451 are sent to the first to tenth interpolation circuits 401, respectively.

  As shown in FIG. 7, the EN generation circuit 381 generates the first EN signal 451 (first interpolation circuit EN) that becomes H level when the count value indicated by the count signal 441 is “1” to 128. Similarly, when the count value indicated by the count signal 441 increases by “128”, the EN generation circuit 381 sends the second EN signal (second interpolation circuit EN) to the second interpolation circuit 401. Send to circuit 401.

  In this way, the EN generation circuit 381 outputs the EN signal 451 every time the count value indicated by the count signal 441 increases by “128”. That is, the EN generation circuit 381 sequentially supplies the first to tenth EN signals (tenth interpolation circuit EN) 451 to sequentially operate the driver IC every time the count value indicated by the count signal 441 increases by “128”. Output.

  Data 331 is input to the first to tenth interpolation circuits 401. When the data 331 corresponding to even pixels is input to the first to tenth interpolation circuits 401, the odd-numbered pixels are not energized. The first to tenth energization patterns are generated by performing the interpolation process. These first to tenth energization patterns are sent to the first to tenth driver ICs 411 as first to tenth data, respectively.

  In other words, the first to tenth interpolation circuits 401 output, as energization data, the first energization signal for de-energizing one of the even pixel data and the odd pixel data in the image data according to the data EN signal. . Further, the first to tenth interpolation circuits 401 output, as energization data, a second energization signal that makes the other of the even pixel data and the odd pixel data non-energized.

  For example, when data “0”, “2”, “4”... For even pixels are input, the first to tenth interpolation circuits 401 are not applied to data “1”, “3”, 5. The first to tenth data is output by interpolating the energization data.

  In this way, the EN generation circuit 381 selects any one of the first to tenth interpolation circuits 401 in accordance with the count signal 441, and the selected (that is, validated) interpolation circuit performs data The interpolation process is performed.

  The latch generation circuit 391 generates a latch signal 461 that is a control signal for the driver IC in response to the count signal 440. As shown in FIG. 7, the latch generation circuit 391 outputs a latch signal 461 that is synchronized with the data EN signal in accordance with the count signal.

  As illustrated in FIG. 7, the first to tenth driver ICs 411 send energization signals to the heating resistors of the heating resistor unit 421 to which the first to tenth driver ICs 411 are connected. At this time, each of the first to tenth driver ICs 411 determines the output timing according to the latch signal. The first to tenth driver ICs 411 send the first to tenth data as energization signals to the heating resistor of the heating resistor unit 421 in synchronization with the clock to cause the heating resistor unit 421 to generate heat in units of driver ICs. .

  The configuration of the driver IC 411 and the heating resistor unit 421 is the same as that of the driver IC 52 and the heating resistor unit 53 described in FIG. 2, but the latch signal 461 is generated by the latch generation circuit 391, and one gradation is generated by the latch signal 291. The data for the odd or even image at is determined.

  Thus, in the embodiment of the present invention, the head control ASIC 3 connected to the recording head 2 controls the heat generation of the recording head 2 using the data EN signal 321, the data 331, and the clock 341. That is, the head control ASIC 3 performs energization control of the recording head 2 using three control lines. As a result, the control lines between the head control ASIC 3 and the recording head 2 can be reduced. As a result, the generation of unnecessary radiation noise and signal delay can be reduced, the resolution can be increased, and the printing speed can be improved.

  In other words, in the embodiment of the present invention, even if the number of driver ICs increases as the resolution of the recording head increases, the control line between the head control ASIC and the recording head does not increase and the recording line of the recording head does not increase. You can control. Furthermore, since only the data related to the heating resistor that generates heat in the heating resistor section is transferred, the recording head can be controlled without a decrease in printing speed.

  As is clear from the above description, in the example shown in FIG. 6, the driver IC 411 functions as driver means, and the SEL 351, the counter circuit 371, the latch generation circuit 391, the EN generation circuit 381, and the interpolation circuit 401 function as transfer means. To do.

  The head control ASIC 3 functions as a control unit. Further, the SEL 351, the counter circuit 371, and the latch generation circuit 391 function as a latch signal generation unit, and the SEL 351, the counter circuit 371, the EN generation circuit 381, and the interpolation circuit 401 function as an output stage.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to these embodiment, Various forms of the range which does not deviate from the summary of this invention are also contained in this invention. .

  For example, the function of the above embodiment may be used as a control method, and this control method may be executed by the printing apparatus. Further, a program having the functions of the above-described embodiments may be used as a control program, and the computer provided in the printing apparatus may be caused to execute the control program. The control program is recorded on a computer-readable recording medium, for example.

[Other Embodiments]
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

2 Recording head 3 Head control ASIC
4 CPU
5 Image processing unit 7 Operation unit 9 FLASH ROM
10 SDRAM
11 SD card 13 LCD
14 LCD driver

Claims (6)

A printing apparatus having a recording head including a plurality of heating resistors, and performing printing on printing paper by heating the recording head,
The heating resistors are divided into a plurality of groups,
Driver means provided for each of the groups, and for generating heat with the energization data indicating the energization pattern in response to a clock signal sent from a control means for controlling the recording head,
Transfer means for sequentially operating the driver means according to a data enable signal sent from the control means, and sending the energization data according to image data sent from the control means to the driver means;
A printing apparatus comprising:   The printing apparatus according to claim 1, wherein the driver unit and the transfer unit are provided in the recording head.   The recording head is connected to the control means by a first control line for receiving the image data, a second control line for receiving the data enable signal, and a third control line for receiving the clock signal. The printing apparatus according to claim 2. The transfer means generates a latch signal for the driver means to latch the energized data in response to the data enable signal; and
The first energization signal, the even pixel data, and the odd number that receive the image data and de-energize one of the even pixel data and the odd pixel data in the image data according to the data enable signal. The output means which outputs the 2nd energization signal which makes the other non-energized state of the data for pixels into the said driver means as said energization data, The any one of Claims 1-3 characterized by the above-mentioned. The printing apparatus as described. A control method for a printing apparatus that includes a recording head including a plurality of heating resistors, and that heats the recording head to perform printing on printing paper,
The heating resistors are divided into a plurality of groups,
Energization data indicating an energization pattern corresponding to image data sent from the control unit by sequentially operating drivers provided in each of the groups in response to a data enable signal sent from a control unit that controls the recording head A first step of sending to the driver;
A second step of causing the heating resistor to generate heat with the energization data in response to a clock signal sent from the control means by the driver;
A control method characterized by comprising: A control program used in a printing apparatus that has a recording head including a plurality of heating resistors, and heats the recording head to perform printing on printing paper,
The heating resistors are divided into a plurality of groups,
A computer provided in the printing apparatus;
In response to a data enable signal sent from a control unit that controls the recording head, drivers provided in each of the groups are sequentially operated, and energization data indicating an energization pattern according to image data is sent to the driver. 1 step,
A second step of causing the heating resistor to generate heat with the energization data in accordance with a clock signal sent from the control unit by the driver;
A control program characterized by causing