JP2010240903A - Printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce dispersion in liquid drops ejected from nozzles when ejecting liquid drops from a plurality of nozzles provided in different positions in a head. <P>SOLUTION: A printer 1 includes, in the printhead 100, multiple sets of ink drop ejection mechanisms 111-116 including ink chambers 1114-1164 holding ink to be supplied to the nozzles 1112-1162, and pressurizing parts 1116-1166 applying pressure to the ink in the ink chambers to eject ink drops from the nozzles. The ink chambers 1114-1164 are lined up in the printhead 100. The printer 1 further includes temperature control parts 120, 130 controlling the temperature of ink in the lined-up ink chambers 1114-1164 so that the temperature of ink in the center ink chambers 1134, 1144 out of the lined-up ink chambers 1114-1164 is higher than that of ink in the ink chambers 1114, 1164 at the ends. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for discharging droplets from a plurality of nozzles.

  2. Description of the Related Art Conventionally, there are printers that perform printing by ejecting ink droplets from a plurality of nozzles arranged in a row to form ink dots on a print medium. In such a printer, an ink chamber is provided in each ink flow path in the print head connected to each nozzle. An ink droplet is ejected from a nozzle provided at one end of the ink chamber by applying pressure to the ink in the ink chamber by a driving means such as a piezo element.

  In such a printer, the weight and speed of the ejected ink droplets differ between the nozzles near the center of the row and the nozzles near the end, and the size of the ink dots formed on the print medium varies. There was a problem that the quality of the printed matter was lowered. More specifically, the amount of ink droplets ejected from nozzles near the center of the row tends to be smaller than the amount of ink droplets ejected from nozzles near the end of the row. This problem is considered to occur because the ink chamber provided near the end of the print head has higher rigidity, and the ink chamber provided near the center of the print head has lower rigidity.

  In order to cope with such a problem, in a certain prior art, in the print head, by providing a dummy ink chamber further outside the ink chamber of the nozzle used for printing, the ink of each nozzle used for printing is provided. The rigidity of the chamber is made uniform, and the weight and speed of the ejected ink droplets are made uniform (Patent Document 1). In another prior art, ejection is performed by changing the drive waveform of a drive unit provided in an ink flow path connected to each nozzle to push out ink droplets between a nozzle near the center of the column and a nozzle near the end. The weight and speed of the ink droplets to be made are uniform (Patent Document 2).

JP 2007-000000 A JP 2008-000000 A

  However, in the former technique, it is necessary to provide dummy ink chambers on the outer side of the nozzles at both ends of the row, so that there is a problem that the print head is increased in size. In the latter technique, in order to generate a plurality of types of drive waveforms, a circuit having a complicated configuration is required as compared with a circuit that generates one type of drive waveforms. Such a problem is not limited to printers that eject ink droplets, and there are widespread techniques for ejecting droplets from a plurality of nozzles provided at different positions in the head.

  The present invention has been made in order to deal with at least a part of the above-described problems. When droplets are ejected from a plurality of nozzles provided at different positions in the head, the droplets ejected from the nozzles The purpose is to reduce the variation.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
The print head includes a plurality of sets of ink droplet ejection mechanisms each including an ink chamber that holds ink to be supplied to the nozzle and a pressure unit that applies pressure to the ink in the ink chamber to eject ink droplets from the nozzle. A printing device,
The ink chambers of the plurality of sets of ink droplet ejection mechanisms are arranged side by side in the print head,
The printing apparatus further includes the ink arranged side by side so that the temperature of the ink in the central ink chamber is higher than the temperature of the ink in the end ink chamber among the ink chambers arranged side by side. A printing apparatus comprising a temperature control unit that controls the temperature of ink in a chamber.

  In such an embodiment, the viscosity of the ink in the central ink chamber is lower than the viscosity of the ink in the end ink chamber. As a result, the amount of ink droplets ejected from the central ink chamber by pressurization is increased as compared with an embodiment without a temperature control unit. For this reason, the amount of ink droplets ejected from the central ink chamber can be brought close to the amount of ink droplets ejected from the end ink chamber by the same pressure. Therefore, the dispersion | variation regarding the droplet discharged from a nozzle can be reduced.

  Note that “the central ink chamber among the ink chambers arranged side by side” has the central ranking when the ink chambers of the “ink chambers arranged side by side” are ranked in the order of arrangement. It is an ink chamber. “The center ink chamber among the ink chambers arranged side by side” is one when the number of “ink chambers arranged side by side” is an odd number, but “the ink chambers arranged side by side” "Is an even number, it is two.

  Further, as an aspect of “controlling the temperature of the ink supplied to the ink chamber”, it is possible to heat or cool the ink in the ink chamber, and to heat or cool the ink before being supplied to the ink chamber. It can also be set as an aspect. The temperature controller preferably controls the temperature of the ink in the ink chamber so that the ink chamber is closer to the center position of the plurality of ink chambers arranged side by side.

[Application Example 2]
A printing apparatus according to application example 1,
The temperature control unit is a printing apparatus provided in the print head.

  With such an aspect, the temperature control unit can control the temperature of each ink chamber in the vicinity of each ink chamber provided in the print head. For this reason, the temperature of the ink in each ink chamber provided in the print head can be accurately controlled.

[Application Example 3]
A printing apparatus according to application example 2,
The temperature controller is
A heat generating portion provided at a position closer to the central ink chamber than the ink chamber at the end, and generating heat;
At least a part of the ink chambers including the central ink chamber among the ink chambers arranged side by side with respect to the direction in which the ink chambers are arranged, provided to the outside of the range in which the heat generating portion is provided. And a transmission unit capable of transmitting heat of the heat generating unit.

  According to such an aspect, at least on one side with the heat generating portion as the center, the temperature of the ink inside the ink chamber closer to the heat generating portion can be increased. As a result, the viscosity of the ink in the ink chamber can be lowered as the ink chamber is closer to the heat generating portion. Therefore, the amount of ink ejected from each nozzle can be made more uniform.

  In the above aspect, the ink chamber in which the transmission unit transmits the heat of the heat generation unit may include the end ink chamber, and the ink chamber in which the transmission unit transmits the heat of the heat generation unit does not include the end ink chamber. It can also be set as an aspect.

[Application Example 4]
A printing apparatus according to application example 2,
The temperature controller is
A first heat generating portion provided at a position closer to the central ink chamber than the ink chamber at the end and generating heat;
A second heat generating portion provided at a position closer to the end ink chamber than the central ink chamber and generating heat,
The first heat generating unit heats the ink in the central ink chamber so that the temperature of the ink in the central ink chamber is higher than the temperature of the ink in the ink chamber at the end,
The second heat generating unit heats the ink in the predetermined ink chamber so that the temperature of the ink in the predetermined ink chamber other than the central ink chamber is lower than the temperature of the ink in the central ink chamber. , Printing device.

  Even in such an aspect, the temperature of the ink in the ink chamber can be controlled so that the temperature of the ink in the central ink chamber is higher than the temperature of the ink in the other ink chambers. As a result, the amount of ink ejected from each nozzle can be made more uniform.

  The “predetermined ink chamber” in which the second heat generating unit heats the ink may include an “end ink chamber” or may be “an ink chamber other than the center and end ink chambers”.

[Application Example 5]
A printing apparatus according to Application Example 1,
An ink tank provided outside the print head and holding ink to be supplied to the ink chamber;
A first ink supply capable of supplying ink from the ink tank to at least a part of the ink chambers arranged side by side and supplying more ink to the central ink chamber than the ink chamber at the end. The ink can be supplied from the ink tank to the path and at least a part of the ink chambers arranged side by side, and a second ink is supplied to the ink chamber at the end than the central ink chamber. A plurality of ink supply paths, including a plurality of ink supply paths,
The temperature controller is
The temperature of the ink in the ink supply path is controlled so that the temperature of the ink in the first ink supply path is higher than the temperature of the ink in the second ink supply path. A printing device.

  Even in such an embodiment, the temperature of the ink can be controlled so that the temperature of the ink in the central ink chamber is higher than the temperature of the ink in the ink chamber at the end. Since the temperature control unit is provided outside the print head, the print head can be made lighter than in a mode in which the temperature control unit is provided in the print head. For this reason, for example, in an aspect in which printing is performed by reciprocating, energy consumed when the print head is conveyed can be reduced.

  The temperature control unit preferably controls the temperature of the ink in the ink supply path so that the ink supply path closer to the center position of the plurality of ink supply paths arranged side by side has a higher ink temperature.

[Application Example 6]
A printing apparatus according to application example 5,
The temperature controller is
A heat generating portion provided at a position closer to the first ink supply path than the second ink supply path and generating heat;
With respect to the direction in which the first and second ink supply paths are arranged, the first and second ink supply paths are provided to the outside of the range where the heat generating portion is provided, and at least some of the ink supply paths including the first ink supply path are provided. And a transmission unit capable of transmitting heat of the heat generating unit.

  According to such an aspect, the temperature of the ink in the first ink supply path close to the heat generating portion can be made higher than that of the ink in the ink supply path far from the heat generating portion as compared with the first ink supply path. As a result, the ink temperature can be controlled so that the temperature of the ink in the central ink chamber is higher than the temperature of the ink in the end ink chamber.

  In the above aspect, the ink supply path through which the transmission unit transmits heat from the heat generation unit may include the second ink supply path, and the ink supply path through which the transmission unit transmits heat from the heat generation unit is the second. An embodiment in which the ink supply path is not included may also be employed.

  As for the plurality of ink supply paths, it is preferable to provide five or more ink supply paths in which ink chambers supplying the most ink are different from each other. As the ink supply path is closer to the center, the temperature of the ink in the ink supply path becomes higher due to the heat generation unit and the transmission unit. Therefore, with such an aspect, the temperature of the ink chamber can be finely controlled.

  The ink supply paths are arranged side by side in the same order as or in the reverse order of the arrangement order of the ink chambers in which the ink supply paths supply the most ink in at least a part located outside the print head. It is preferable.

[Application Example 7]
A printing apparatus according to application example 5,
The temperature controller is
A first heat generating part provided at a position closer to the first ink supply path than the second ink supply path;
A second heat generating part provided at a position closer to the second ink supply path than the first ink supply path,
The first heat generating unit removes ink in the first ink supply path so that the temperature of ink in the first ink supply path is higher than the temperature of ink in the second ink supply path. Heated,
The second heat generating unit may be configured so that the temperature of ink in a predetermined ink supply path other than the first ink supply path is lower than the temperature of ink in the first ink supply path. A printing device that heats ink in a supply path.

  Even in such an aspect, the temperature of the ink in the ink chamber can be controlled so that the temperature of the ink in the central ink chamber is higher than the temperature of the ink in the other ink chambers. As a result, the amount of ink ejected from each nozzle can be made more uniform.

  The “ink supply path other than the first ink supply path” in which the second heat generating unit heats the ink may include a “second ink supply path”. “Other than the first and second ink supply paths” Ink supply path ”.

Note that the present invention can be realized in various modes as described below.
(1) Print head, printing apparatus, printing method.
(2) A device for managing the amount of ink droplets and a method for managing the amount of ink droplets.

1 is an explanatory diagram illustrating an overall configuration of a printer 1 according to a first embodiment. FIG. Explanatory drawing which shows the whole structure of the printer 1b which is 2nd Example. Explanatory drawing which shows the whole structure of the printer 1c which is 3rd Example.

A. First embodiment:
FIG. 1 is an explanatory diagram illustrating the overall configuration of a printer 1 according to the first embodiment. The printer 1 includes a print head 100, an ink tank 200, and an ink supply pipe 400 that connects the print head 100 and the ink tank 200. The printer 1 further includes a print medium transport unit that transports the print medium to the print head 100, a main scanning unit that reciprocates the print head 100 at a position facing the print medium, and a control unit 1200 that controls each unit. And comprising.

  In FIG. 1, in order to facilitate understanding of the technology, a cross section of the print head 100 and a part of the print head 100 provided above the cross section (front side with respect to the plane of FIG. 1) The structure is displayed in an overlapping manner. In FIG. 1, in order to facilitate understanding of the technology, illustrations of a power supply and an electric circuit for driving the print medium transport unit, the main scanning unit, and each unit of the printer 1 are omitted.

  The print head 100 is a head for ejecting ink droplets toward a print medium to form dots on the print medium. The print head 100 includes a plurality of ink droplet ejection mechanisms 111 to 116 for ejecting ink droplets, an ink supply path 140 for supplying ink to the ink droplet ejection mechanisms 111 to 116, and heat generation to heat the ink. And a transmission unit 130 for transmitting the heat of the heat generation unit to the ink of the ink droplet ejection mechanisms 111 to 116.

  The ink droplet ejection mechanism 111 has a nozzle 1112 that ejects ink droplets, an ink chamber 1114 that holds ink to be supplied to the nozzle 1112 upon receiving ink supply from the ink supply path 140, and the ink chamber above (FIG. 1). And a piezo element 1116 for pressing the ink in the ink chamber 1114 by pressing from the front side of the paper. When the ink in the ink chamber 1114 is pressurized by the piezo element 1116, ink droplets are ejected from the nozzle 1112 in the direction from the paper surface to the back.

  The other ink droplet ejection mechanisms 112 to 116 have the same configuration. In the ink droplet ejection mechanisms 112 to 116 in FIG. 1, the reference numeral with 2 added to the end of the reference numerals 112 to 116 assigned to each ink droplet ejection mechanism represents a nozzle. A symbol with 4 at the end of the symbol assigned to the ink droplet ejection mechanism represents an ink chamber. A code with 6 added to the end of the code assigned to the ink droplet ejection mechanism represents a piezo element.

  In the print head 100, the ink chambers 1114, 1124, 1134, 1144, 1154, and 1164 of the six ink droplet ejection mechanisms 111 to 116 are arranged in that order in the direction of the arrow Ar as shown in FIG. The Of the six ink chambers arranged side by side, the ink chambers 1134 and 1144 at the third and fourth positions from the top are referred to as “central ink chambers” in this specification. Also, the ink chambers 1114 and 1164 at both ends are referred to as “end ink chambers” in this specification.

  The ink supply path 140 in the print head 100 receives ink supplied from the ink supply pipe 400 via the connection unit 406. The ink supply path 140 supplies ink to the ink chambers 1114, 1124, 1134, 1144, 1154, and 1164 as indicated by an arrow Ai 0 in FIG. Hereinafter, the ink chambers 1114, 1124, 1134, 1144, 1154, and 1164 may be collectively referred to as “ink chambers 1114 to 1164”.

  The heat generating unit 120 generates heat when power is supplied from a power source (not shown). The heat generating unit 120 is controlled to be turned ON / OFF by the control unit 1200. As a result, the average heat generation amount per unit time by the heat generating unit 120 is controlled by the control unit 1200. The heat generating part 120 is provided in the range of Rh1 with respect to the direction Ar in which the ink chambers are arranged. The range Rh1 is a range that overlaps with the ink chambers 1134 and 1144 in the ink chamber arrangement direction Ar and does not overlap with other ink chambers. That is, the heat generating unit 120 is provided at a position closer to the central ink chambers 1134 and 1144 than the ink chambers 1114 and 1164 at the ends.

  The transmission unit 130 is a metal plate provided in a range Rt1 that exceeds the range Rh1 occupied by the heat generating unit 120 in the ink chamber arrangement direction Ar. More specifically, the range Rt1 is a range that overlaps the six ink chambers 1114 to 1164 in the direction Ar of the ink chamber arrangement. The heat generating unit 120 is provided on the transmission unit 130 in contact with the transmission unit 130. The transmission unit 130 is provided on a member constituting the ceiling of the six ink chambers 1114 to 1164. As a result, the transmission unit 130 can transmit the heat of the heat generation unit 120 to the ink chambers 1114 to 1164. In addition, the material which comprises the outer peripheral part of the ink chambers 1114 to 1164 and the ceiling part between the transmission parts is ceramic.

  More heat is transferred per unit time to the central ink chambers 1134 and 1144 in the position overlapping the heat generating portion 120 in the ink chamber arrangement direction Ar than in the other ink chambers in positions not overlapping the heat generating portion 120. Is done. As for the other ink chambers, the closer to the central ink chambers 1134 and 1144, the more heat is transmitted per unit time by the transmission unit 130. As a result, the ink chamber closer to the central position CP of the plurality of ink chambers arranged side by side has a higher ink temperature. A graph of the ink temperature in the ink chambers 1114 to 1164 is shown on the left side of FIG. Each bar graph at a position aligned with each ink chamber represents the temperature of the ink in each ink chamber. The temperature of these inks can be obtained, for example, by measuring the temperature of ink ejected from each nozzle.

  In the present embodiment, the heat generating unit 120 and the transmission unit 130 are provided in the print head 100. For this reason, it is possible to accurately control the ink temperature of each ink chamber in the print head 100.

  Note that the central position CP of the plurality of ink chambers arranged side by side is between two points closest to each other in the gap between the two central ink chambers when the number of ink chambers arranged side by side is an even number. This is the midpoint of the direction in which the ink chambers are arranged. When the number of ink chambers arranged side by side is an odd number, it is the midpoint of the width of the widest portion in the direction of the ink chamber arrangement in the gap of one central ink chamber. In this embodiment, there are six ink chambers. Therefore, the central position CP of the ink chamber is a position between the central ink chambers 1134 and 1144 shown in FIG.

  The print head 100 having the above configuration is reciprocated in a direction indicated by an arrow MS in FIG. 1 by a main scanning unit (not shown). This operation is also called “main scanning”.

  The ink tank 200 stores ink to be supplied to each ink chamber of the print head 100. The ink in the ink tank 200 is sent out by a pump (not shown) and sent to the print head 100 through the ink supply pipe 400.

  The ink supply pipe 400 is made of a flexible material in at least a part of the section. The portion made of the flexible material connects the portions of the ink supply pipes 400 on both sides with a certain margin. Therefore, the ink tank 200 and the print head 100 are maintained even during the main scanning, and ink is supplied from the ink tank 200 to the print head 100.

  The print head 100 is controlled by the control unit 1200 while being reciprocated by the main scanning unit, and ejects ink droplets from the nozzles at predetermined timings. Meanwhile, the print medium is conveyed in the direction indicated by the arrow SS by the print medium conveyance unit controlled by the control unit 1200, stopped at a predetermined position, and these processes are repeated. This process is called “sub-scanning”. Ink droplets are ejected from each nozzle, and during that time, main scanning and sub-scanning are performed, whereby ink dots are formed at predetermined positions on the printing medium, and printed matter is generated.

  In general, in a print head of a printer that ejects ink droplets, ink chambers that are gaps for containing ink to be ejected are arranged side by side. For this reason, the rigidity of the structure constituting the ink chamber is low near the center in the direction of arrangement of the ink chambers, and the rigidity is high near the ends. For this reason, in the vicinity of the center of the ink chamber arrangement direction, when the piezo element pushes the ink chamber, the side wall of the ink chamber bends to increase the capacity of the ink chamber, and the pressure increases as the ink chamber at the end increases. There are things that do not. As a result, the ink chamber closer to the center sandwiched between more ink chambers tends to reduce the weight of the ink droplets ejected from the nozzles. Note that the above explanation is an example of the cause of variation in ink droplets, and the reason why the weight of the ink droplets ejected in the ink chamber closer to the central ink chamber becomes smaller may be due to other events. is there.

  In the present embodiment, as described above, the temperature of the ink is higher in the ink chamber closer to the central position CP due to the heating by the heat generation unit 120 and the transmission unit 130. As a result, the closer the ink chamber to the central position CP, the lower the viscosity of the ink in the ink chamber. For this reason, according to the present embodiment, a larger amount of ink droplets can be ejected from the ink chamber near the center than in the case where the heat generating unit 120 and the transmission unit 130 are not provided. As a result, it is possible to cancel the tendency that the weight of the ink droplet ejected from the nozzle becomes smaller as the ink chamber is closer to the center position, and the weight and flying speed of the ink droplet ejected by each ink droplet ejecting mechanism 111 to 116. Can be reduced.

  In this specification, “the closer to A, the higher X (the larger)” means that X2 at the second location closer to A than the first location is equal to X1 at the first location. , Means equal or higher (larger). And, “X closer to A becomes lower (smaller)” means that X2 at the second location closer to A than the first location is equal to or lower than X1 at the first location ( Means big).

  In this embodiment, the piezo elements 1116, 1126, 1136, 1146, 1156, 1166 correspond to a “pressurizing unit” in “means for solving the problems”. The heat generation unit 120 and the transmission unit 130 correspond to a “temperature control unit”.

B. Second embodiment:
FIG. 2 is an explanatory diagram showing the overall configuration of the printer 1b according to the second embodiment. The printer 1b includes three heat generating units 122, 124, and 126 instead of the heat generating unit 120 in the printer 1 of the first embodiment. Then, instead of the transmission unit 130 in the printer 1 of the first embodiment, three transmission units 132, 134, and 136 are provided. Other points of the hardware configuration of the printer 1b are the same as those of the printer 1. In FIG. 2, in order to facilitate understanding of the technology, the illustration of the control unit 1200 that controls each unit is omitted. 2, the same components as those shown in FIG. 1 are denoted by the same reference numerals as those shown in FIG.

  The heat generating part 124 has a maximum heat generation amount per unit time lower than that of the heat generating part 120 of the printer 1 of the first embodiment. Other points of the configuration of the heat generating unit 124 are the same as those of the heat generating unit 120 of the printer 1 of the first embodiment. The heat generating part 124 is provided in a range Rh4 located on the ink chambers 1134 and 1144 in the ink chamber arrangement direction Ar. That is, the heat generating portion 124 is provided at a position closer to the central ink chambers 1134 and 1144 than the ink chambers 1114 and 1164 at the ends.

  The heat generating units 122 and 126 have a maximum heat generation amount per unit time lower than that of the heat generating unit 124. Other points of the configuration of the heat generating units 122 and 126 are the same as those of the heat generating unit 120 of the printer 1 of the first embodiment. The heat generating portion 122 is provided in a range Rh2 located on the ink chambers 1114 and 1124 in the ink chamber arrangement direction Ar. That is, the heat generating part 122 is provided at a position closer to the end ink chamber 1114 than the central ink chambers 1134 and 1144. On the other hand, the heat generating portion 126 is provided in a range Rh6 positioned on the ink chambers 1154 and 1164 in the direction Ar of the ink chamber arrangement. That is, the heat generating portion 126 is provided at a position closer to the ink chamber 1164 at the end than the central ink chambers 1134 and 1144.

  The transmission unit 134 is a metal plate provided in a range Rt4 that exceeds the range Rh4 occupied by the heat generating unit 124 in the ink chamber arrangement direction Ar. More specifically, the range Rt4 is a range that overlaps the ink chambers 1134 and 1144 in the direction Ar of the ink chamber arrangement. The heat generating part 124 is provided on the transmission part 134 in contact with the transmission part 134. The transmission unit 134 is provided on a member constituting the ceiling of the ink chambers 1134 and 1144. As a result, the transmission unit 134 can efficiently transmit the heat of the heat generation unit 124 to the ink chambers 1134 and 1144.

  The transmission unit 132, the heat generation unit 122, and the ink chambers 1114, 1124 also have the same positional relationship as the transmission unit 134, the heat generation unit 124, and the ink chambers 1134, 1144. The transmission unit 136, the heat generation unit 126, and the ink chambers 1154, 1164 also have the same positional relationship as the transmission unit 134, the heat generation unit 124, and the ink chambers 1134, 1144.

  In the second embodiment, the control unit 1200 (not shown in FIG. 2) turns on / off the heat generating units 122, 124, 126 at the same timing. During the ON period, the heat generating sections 122, 124, and 126 are controlled so as to generate heat with the maximum heat generation amount per unit time. As a result, the average heat generation amount per unit time of the heat generating units 122 and 126 is smaller than the average heat generation amount per unit time of the heat generating unit 124. Therefore, in this embodiment, the temperature of the ink in the ink chambers 1114 and 1124 heated by the heat generating unit 122 and the temperature of the ink in the ink chambers 1154 and 1164 heated by the heat generating unit 126 are heated by the heat generating unit 124. It becomes lower than the temperature of the ink in the ink chambers 1134 and 1144. A graph of the ink temperature in the ink chambers 1114 to 1164 is shown on the left side of FIG.

  Also in the embodiment as in the second embodiment, the ink temperature is higher in the ink chamber closer to the central position CP (see the left side of FIG. 2). As a result, the closer the ink chamber to the central position CP, the lower the viscosity of the ink in the ink chamber. For this reason, according to the present embodiment, as in the first embodiment, it is possible to cancel the tendency that the weight of the ink droplet ejected from the nozzle becomes smaller as the ink chamber is closer to the center position. Variations in the weight and flying speed of the ink droplets ejected by the droplet ejection mechanisms 111 to 116 can be reduced.

  As described above, in this specification, “the closer to A, the higher X (the larger)” means that the second location closer to A than the first location with respect to X1 at the first location. X2 in the places of means that they are equal or high (large). And, “X closer to A becomes lower (smaller)” means that X2 at the second location closer to A than the first location is equal to or lower than X1 at the first location ( Means big).

  In this embodiment, since a plurality of heat generating portions are provided, the temperature distribution of each ink chamber can be set to a desired state by appropriately setting the heat generation amount of each heat generating portion. In other words, it is easier to realize a desirable temperature distribution as compared with the first embodiment in which the temperature distribution is determined by the transmission unit.

  In the present embodiment, the heat generating portion 124 corresponds to the “first heat generating portion” in “Means for Solving the Problems”. The heat generating parts 122 and 126 correspond to the “second heat generating part”.

C. Third embodiment:
FIG. 3 is an explanatory diagram showing the overall configuration of the printer 1c according to the third embodiment. The printer 1c includes three ink supply tubes 420, 440, and 460 instead of the ink supply tube 400 in the printer 1 of the first embodiment. The print head 100c is supplied with ink from the ink tank 200 via these three ink supply pipes 420, 440, and 460. The printer 1c includes a heat generating unit 128 outside the print head 100c instead of the heat generating unit 120 in the printer 1 of the first embodiment. A transmission unit 138 is provided instead of the transmission unit 130 in the printer 1 of the first embodiment. Other points of the hardware configuration of the printer 1b are the same as those of the printer 1. In FIG. 3, the same components as those shown in FIG. 1 are denoted by the same reference numerals as those shown in FIG.

  The ink supply pipe 440 supplies ink to the ink supply path 140 in the print head 100 via the connection portion 446. The ink supplied from the ink supply pipe 440 is mainly supplied to the central ink chambers 1134 and 1144 (see arrow Ai4 in FIG. 3). That is, the ink supply tube 420 supplies more ink to the central ink chambers 1134 and 1144 than the ink chambers 1114 and 1164 at the ends.

  The ink supply pipe 420 supplies ink to the ink supply path 140 in the print head 100 via the connection portion 426. The ink supplied from the ink supply pipe 420 is mainly supplied to the ink chambers 1114 and 1124 (see arrow Ai2 in FIG. 3). That is, the ink supply tube 420 supplies more ink to the ink chamber 1114 at the end than the ink chambers 1134 and 1144 at the center.

  The ink supply pipe 460 supplies ink to the ink supply path 140 in the print head 100 via the connection portion 466. The ink supplied from the ink supply pipe 460 is mainly supplied to the ink chambers 1154 and 1164 (see arrow Ai6 in FIG. 3). That is, the ink supply tube 460 supplies more ink to the ink chamber 1164 at the end than the ink chambers 1134 and 1144 at the center.

  The ink supply tubes 420, 440, and 460 are arranged in parallel in a part of the section Rp outside the print head 100c. In the section Rp, the order of arrangement of the ink supply pipes 420, 440, and 460 is the same as the arrangement of the ink chambers that supply the most ink. That is, the order of arrangement of the ink supply pipes 420, 440, and 460 is “ink chamber 1114 or ink chamber 1124”, “ink chamber 1134 or ink chamber 1144”, and “ink chamber 1154 or ink chamber 1164”. The order is the same. The configurations of the ink supply tubes 420, 440, and 460 are substantially the same as the ink supply tube 400 of the printer 1 of the first embodiment.

  The heat generating unit 128 has a maximum heat generation amount per unit time higher than that of the heat generating unit 120 of the printer 1 of the first embodiment. For this reason, even if the ink heated by the heat generating portion 128 is cooled while being supplied to each ink chamber, the temperature becomes the same as the temperature of the ink chamber in the first embodiment. Other points of the configuration of the heat generating unit 128 are the same as those of the heat generating unit 120 of the printer 1 of the first embodiment. The heat generating part 124 is provided in a range Rh8 located on the ink supply pipe 440 in the direction Ap of the arrangement of the ink supply pipes 420, 440, and 460. That is, the heat generating part 124 is provided at a position closer to the ink supply pipe 440 than the ink supply pipes 420 and 460.

  The transmission unit 138 is a metal plate provided in a range Rt8 that exceeds the range Rh8 occupied by the heat generating unit 128 in the direction Ap of the arrangement of the ink supply tubes 420, 440, and 460. More specifically, the range Rt8 is a range that overlaps with the ink supply tubes 420, 440, and 460 in the direction Ap of the arrangement of the ink supply tubes 420, 440, and 460. The heat generating unit 128 is provided on the transmission unit 138 in contact with the transmission unit 138. The transmission unit 138 is provided in contact with the ink supply pipes 420, 440 and 460. As a result, the transmission unit 138 can transmit the heat of the heat generating unit 128 to the ink supply tubes 420, 440, and 460.

  With respect to the direction Ap of the arrangement of the ink supply tubes 420, 440, 460, the central ink supply tube 440 at the position overlapping the heat generating portion 128 is more than the other ink supply tubes 420, 460 at the position not overlapping the heat generating portion 128. However, a lot of heat is transferred per unit time. For this reason, the temperature of the ink in the central ink supply pipe 440 is higher than the temperature of the ink in the ink supply pipes 420 and 460. As a result, in each of the ink chambers 1114 to 1164 to which ink is supplied from the ink supply pipes 420, 440, and 460, the temperature of the ink is higher as the ink chamber is closer to the central position CP. A graph of the ink temperature in the ink chambers 1114 to 1164 is shown on the left side of FIG.

  Also in the embodiment as in the third embodiment, the ink temperature is higher in the ink chamber closer to the central position CP (see the left side of FIG. 3). As a result, the closer the ink chamber to the central position CP, the lower the viscosity of the ink in the ink chamber. For this reason, according to the present embodiment, as in the first and second embodiments, it is possible to cancel the tendency that the weight of the ink droplet ejected from the nozzle becomes smaller as the ink chamber is closer to the center position. In addition, variations in the weight and flying speed of the ink droplets ejected by the ink droplet ejection mechanisms 111 to 116 can be reduced.

  In the third embodiment, the heat generating unit 128 and the transmission unit 138 are provided outside the print head 100c. For this reason, the print head 100c can be made lighter than the print head 100 of the first embodiment and the print head 100b of the second embodiment. As a result, it is easier to accurately control the position of the print head 100c in main scanning than in the first and second embodiments. In addition, the power consumed by the main scanning unit in the main scanning can be reduced.

  Furthermore, in the third embodiment, the heat generated by the heat generating unit 128 and the transmission unit 138 is not easily transmitted to the piezo elements 1116, 1126, 1136, 1146, 1156, and 1166 as pressure units. Therefore, there is little possibility that the heat generated by the heat generating unit 128 and the transmission unit 138 will adversely affect the operation of these pressurizing units.

  In the present embodiment, the ink supply pipe 440 corresponds to a “first ink supply path” in “means for solving the problems”. The ink supply pipes 420 and 460 correspond to the “second ink supply path”.

D. Variation:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

D1. Modification 1:
In the first embodiment, the transmission unit 130 is provided in a range overlapping with the six ink chambers 1114 to 1164 in the direction Ar of the ink chamber arrangement, and transmits heat of the heat generating unit 120 to these ink chambers. . The transmission unit that transmits the heat of the heat generation unit may be provided at a position that does not overlap with respect to at least a part of the ink chambers in the direction Ar in which the ink chambers are arranged. And it can also be set as the aspect which can transmit the heat of a heat-emitting part with respect to the ink chamber in the position which does not overlap, and can also be set as the aspect which cannot transmit the heat of a heat-generating part.

  For example, in contrast to the first embodiment, the transmission unit 130 is provided in a range that does not overlap with the end ink chambers 1114 and 1164, and the transmission unit 130 does not transmit the heat of the heat generating unit to the end ink chambers 1114 and 1164. It can also be set as an aspect. Further, in contrast to the first embodiment, the transmission unit 130 is provided in a range that does not overlap the ink chambers 1114, 1124, 1154, and 1164 at the end, and the transmission unit 130 is provided in the ink chambers 1124, 1134, 1144, and 1154. It is also possible to adopt a mode in which the heat of the heat generating portion is transmitted and heat is not transmitted to the ink chambers 1114 and 1164 at the ends.

  The transmission unit is provided in a range that exceeds the heat generation unit in the direction in which the ink chambers are arranged, and is provided so that heat can be transmitted to the central ink chamber and the ink chambers other than the central ink chamber. It is preferable. And about the ink chamber which conveys heat, it is preferable that the transmission part is provided in the range which overlaps with those ink chambers about the direction of an ink chamber arrangement.

In the aspect in which the heat generating part and the transmission part as in the third embodiment are provided outside the print head,
The transmission unit that transmits the heat of the heat generation unit may be provided at a position that does not overlap with respect to the direction Ap of the arrangement of the ink supply paths with respect to at least a part of the ink supply paths. And it can also be set as the aspect which can transmit the heat of a heat generating part with respect to the ink supply path in the position which does not overlap, and can also be set as the aspect which cannot transmit the heat of a heat generating part.

  The transmission unit is provided in a range that exceeds the heat generating unit in the direction in which the ink supply paths are arranged, and can transmit heat to the central ink supply path and ink supply paths other than the central ink supply path. It is preferable to be provided. And about the ink supply path which conveys heat, it is preferable that the transmission part is provided in the range which overlaps those ink chambers about the direction of the arrangement | sequence of an ink chamber.

D2. Modification 2:
In the second embodiment, the heat of one heat generating portion is transmitted to the two ink chambers via the transmitting portion (see the transmitting portions 132, 134, and 136 in FIG. 2). However, when the plurality of heat generating portions are provided in a one-to-one manner with respect to the ink chamber to be heated, it is possible to adopt a mode in which the transmission portion is not provided. Also, when the heat generating portion is provided at an intermediate position between the adjacent ink chambers and one heat generating portion can heat the ink in the ink chambers on both sides, the transmission portion may not be provided. it can. In such an embodiment, the heat generating portion can be provided in all the gaps between adjacent ink chambers, or can be provided in every other gap among the gaps between adjacent ink chambers.

  Similarly, when the plurality of heat generating units are provided in a one-to-one manner with respect to the ink supply pipe to be heated, it is possible to adopt a mode in which no transmission unit is provided. Further, when the heat generating part is provided at an intermediate position between the adjacent ink supply pipes and one heat generating part can heat the ink of the ink supply pipes on both sides, the transmission part is not provided. You can also In such an embodiment, the heat generating portion can be provided in all the gaps between the adjacent ink supply pipes, or can be provided in every other gap among the gaps between the adjacent ink supply pipes.

D3. Modification 3:
In the second embodiment, the heat generating parts 122 and 126 have a maximum heat generation amount per unit time lower than that of the heat generating part 124. And each heat generating part 122,124,126 is turned ON / OFF at the same timing. As a result, the average heat generation amount per unit time of the heat generating units 122 and 126 is smaller than the average heat generation amount per unit time of the heat generating unit 124. However, the heat generation amount per unit time of the plurality of heat generating units can be controlled in other manners.

  For example, the amount of heat generated per unit time of the plurality of heat generating units can be controlled by changing the time for the control unit to turn on for each heat generating unit. In such an embodiment, the maximum amount of heat generated per unit time of the plurality of heat generating units may be different or the same.

  Further, in each of the above embodiments, it is preferable that a temperature sensor for determining the temperature of the ink in the ink chamber or the ink supply pipe is provided, and the control unit switches ON / OFF of the heat generating unit according to the output of the temperature sensor. . In the aspect including a plurality of heat generating units, the control unit switches on / off of each heat generating unit according to the output of the temperature sensor, so that the temperature distribution of each ink chamber is always controlled to a desirable distribution. Can do. For this reason, with such an embodiment, the ink droplets ejected from the respective ink chambers can be made highly uniform at all times during temperature control.

D4. Modification 4:
In the second embodiment, the ink in each ink chamber of the ink droplet ejection mechanisms 111 to 116 is heated by the heating units 122, 124, and 126. However, some ink chambers may be not heated. For example, as compared with the second embodiment, the heating unit 124 and the transmission unit 132 may be provided in a range that does not overlap the ink chamber 1114. The heating unit 126 and the transmission unit 136 may be provided in a range that does not overlap with the ink chamber 1164.

  In other words, in an aspect having a plurality of heat generating portions, the heat generating portion provided at a position closer to the ink chamber at the end than the central ink chamber has the temperature of the ink in a predetermined ink chamber other than the central ink chamber as the central ink chamber. The ink in these predetermined ink chambers (the ink chambers 1124 and 1154 in the above embodiment) can be heated so that the temperature of the ink in the chamber is lower.

D5. Modification 5:
In the third embodiment, the order of the ink supply pipes 420, 440, and 460 is the same as the order of the ink chambers that supply the most ink. However, the order of arrangement of the plurality of ink supply pipes as the ink supply path can be reversed to the order of the ink chambers each supplying the most ink. Also in such an aspect, the temperature distribution of the ink in each ink chamber can be controlled by controlling the temperature distribution of the ink in the ink supply path.

D6. Modification 6:
In the third embodiment, a transmission unit 138 that transmits heat of the heat generating unit 128 is provided in each ink supply path. However, it is also possible to adopt a mode in which the transmission unit 138 is not provided in the mode of the third embodiment. In such an embodiment, the ink in the ink supply tube 440 is heated by the heat generating unit 128, and the ink in the ink supply tubes 420 and 460 is not heated. Even in such an aspect, the ink temperature can be controlled so that the ink temperature is higher in the ink chamber closer to the central position CP.

  That is, by providing an ink supply path that is heated by the heat generating part and an ink supply path that is not heated by the heat generating part, the ink temperature of the ink chamber to which ink is supplied from each ink supply path can also be controlled.

D7. Modification 7:
The printer 1 c according to the third embodiment transmits the heat of one heat generating unit 128 to each ink supply tube 420, 440, 460 via the transmission unit 138. However, as in the third embodiment, in a mode in which the ink in the ink supply pipes 420, 440, and 460 is heated, a plurality of heat generating portions can be used as in the second embodiment.

  In such an aspect, the heat generating section that heats the ink supply pipe that supplies ink to the central ink chamber (the ink supply pipe 440 in the third embodiment) has an ink supply pipe that supplies ink to the end ink chamber ( In the third embodiment, the ink that supplies ink to the central ink chamber so that the temperature of the ink in the ink supply tube that supplies ink to the central ink chamber is higher than the ink in the ink supply tubes 420 and 460). It is preferable to heat the supply pipe. The heating unit for heating the ink supply tube for supplying ink to the end ink chamber has a higher temperature in the ink supply tube for supplying ink to the end ink chamber than for the ink in the ink supply tube for supplying ink to the central ink chamber. It is preferable to heat the ink supply tube that supplies ink to the ink chamber at the end so that the temperature of the ink becomes low.

  The temperature control unit preferably controls the temperature of the ink in the ink supply path so that the ink supply path is closer to the center position of the plurality of ink supply paths arranged side by side. . The “center position of the plurality of ink supply paths arranged side by side” refers to the distance between the two closest points of the two central ink supply paths when the number of ink supply paths arranged side by side is an even number. This is the midpoint of the direction of arrangement of the ink supply paths. When the number of ink supply paths arranged side by side is an odd number, it is the midpoint of the width of the widest portion in the direction of the arrangement of the ink supply paths of one central ink supply path. In the third embodiment, there are three ink supply paths. For this reason, the central position CP2 of the ink supply path is the position in the central ink supply path 440 shown in FIG.

  Note that “the central ink supply path among the ink supply paths arranged side by side” is the center when the ink supply paths of the “ink supply paths arranged side by side” are ranked in the order of arrangement. Ink supply paths having the following order. “The center ink supply path among the ink supply paths arranged side by side” is one when the number of “ink supply paths arranged side by side” is an odd number. When the number of “ink supply paths” is an even number, the number is two.

  For example, a first heat generating part provided at a position closer to the ink supply path 440 than the ink supply paths 420 and 460 and a second heat generating part provided at a position closer to the ink supply paths 420 and 460 than the ink supply path 440. And an aspect comprising: Then, the first heat generating unit heats the ink in the ink supply path 440 so that the temperature of the ink in the ink supply path 440 is higher than the temperature of the ink in the ink supply paths 420 and 460. Then, the second heat generating unit is provided in the ink supply paths 420 and 460 so that the temperature of the ink in the ink supply paths 420 and 460 other than the ink supply path 440 is lower than the temperature of the ink in the ink supply path 440. Heat the ink.

  Even in such an aspect, the ink temperature can be controlled so that the ink temperature is higher in the ink chamber closer to the central position CP. In the above aspect, an ink supply path that is not heated by the heat generating portion can be further provided.

D8. Modification 8:
In the third embodiment, the temperature of the ink in the ink chamber is controlled by overheating the ink in the ink supply pipe. However, the ink temperature control can be realized in other manners. For example, a plurality of ink supply pipes 420, 440, and 460 of the third embodiment are connected to different ink tanks, respectively, and the ink in the ink chamber receiving the ink supply is controlled by heating the ink in the ink tank. Can also be done.

  The ink tank for controlling the temperature of the ink is preferably not a main tank but a sub tank that receives ink supplied from the main tank and temporarily stores the ink and supplies the ink to the print head. The ink tank 200 shown in FIGS. 1 to 3 can be grasped as a main tank and can be grasped as a sub tank.

D9. Modification 9:
In the above embodiment, the ink droplet ejection mechanisms of the print heads 100, 100b, and 100c are provided in a line. However, the ink droplet ejection mechanisms may be arranged in two or more rows. In the aspect in which the ink droplet ejection mechanisms are provided in two rows, for example, an aspect in which the ink droplet ejection mechanisms are respectively provided at positions symmetrical to the ink droplet ejection mechanisms 111 to 116 with respect to the ink supply path 140. It is preferable to do.

D10. Modification 10:
In each of the above embodiments, the temperature of the ink is controlled by heating the ink. However, the temperature of the ink can be controlled by cooling the ink. Also, the temperature of the ink can be controlled by using both heating and cooling of the ink. For example, by heating the ink supplied to each ink chamber in advance and cooling the ink supplied to the end ink chamber, the temperature of the ink in the center ink chamber becomes the temperature of the ink in the end ink chamber. The temperature can also be controlled to be higher than that.

DESCRIPTION OF SYMBOLS 1, 1b, 1c ... Printer 100, 100b, 100c ... Print head 111-116 ... Ink droplet discharge mechanism 1112, 1122, 1132, 1142, 1152, 1162 ... Nozzle 1114, 1124, 1134, 1144, 1154, 1164 ... Ink chamber 1116, 1126, 1136, 1146, 1156, 1166... Piezo elements 120, 122, 124, 126, 128... Heating section 130, 132, 134, 136, 138... Transmitting section 140. Ink supply path 200. Ink tanks 400, 420 , 440, 460 ... Ink supply pipes 406, 426, 446, 466 ... Connection parts 1200, 1200c ... Control parts Ai0, Ai2, Ai4, Ai6 ... Arrows indicating the flow of ink Ap ... Direction of arrangement of ink supply pipes Ar ... Ink Room direction CP ... Center position of a plurality of ink chambers arranged side by side MS: Main scanning direction Rh1: Range in which the heat generation unit 120 is provided Rh2: Range in which the heat generation unit 122 is provided Rh4: Range in which the heat generation unit 124 is provided Rh6: Heat generation unit 126 in which R 126 is provided Rh 8 is a range in which the ink supply pipes 420, 440, and 460 are arranged in parallel Rt 1 is a range in which the transmission unit 130 is provided Rt 2 is a range in which the transmission unit 132 is provided Rt 4 ... range in which transmission unit 134 is provided Rt6 ... range in which transmission unit 136 is provided Rt8 ... range in which transmission unit 138 is provided SS ... direction of sub-scanning

Claims (7)

The print head includes a plurality of sets of ink droplet ejection mechanisms each including an ink chamber that holds ink to be supplied to the nozzle and a pressure unit that applies pressure to the ink in the ink chamber to eject ink droplets from the nozzle. A printing device,
The ink chambers of the plurality of sets of ink droplet ejection mechanisms are arranged side by side in the print head,
The printing apparatus further includes the ink arranged side by side so that the temperature of the ink in the central ink chamber is higher than the temperature of the ink in the end ink chamber among the ink chambers arranged side by side. A printing apparatus comprising a temperature control unit that controls the temperature of ink in a chamber. The printing apparatus according to claim 1,
The temperature control unit is a printing apparatus provided in the print head. The printing apparatus according to claim 2,
The temperature controller is
A heat generating portion provided at a position closer to the central ink chamber than the ink chamber at the end, and generating heat;
At least a part of the ink chambers including the central ink chamber among the ink chambers arranged side by side with respect to the direction in which the ink chambers are arranged, provided to the outside of the range in which the heat generating portion is provided. And a transmission unit capable of transmitting heat of the heat generating unit. The printing apparatus according to claim 2,
The temperature controller is
A first heat generating portion provided at a position closer to the central ink chamber than the ink chamber at the end and generating heat;
A second heat generating portion provided at a position closer to the end ink chamber than the central ink chamber and generating heat,
The first heat generating unit heats the ink in the central ink chamber so that the temperature of the ink in the central ink chamber is higher than the temperature of the ink in the ink chamber at the end,
The second heat generating unit heats the ink in the predetermined ink chamber so that the temperature of the ink in the predetermined ink chamber other than the central ink chamber is lower than the temperature of the ink in the central ink chamber. , Printing device. The printing apparatus according to claim 1, further comprising:
An ink tank provided outside the print head and holding ink to be supplied to the ink chamber;
A first ink supply capable of supplying ink from the ink tank to at least a part of the ink chambers arranged side by side and supplying more ink to the central ink chamber than the ink chamber at the end. The ink can be supplied from the ink tank to the path and at least a part of the ink chambers arranged side by side, and a second ink is supplied to the ink chamber at the end than the central ink chamber. A plurality of ink supply paths, including a plurality of ink supply paths,
The temperature controller is
The temperature of the ink in the ink supply path is controlled so that the temperature of the ink in the first ink supply path is higher than the temperature of the ink in the second ink supply path. A printing device. The printing apparatus according to claim 5,
The temperature controller is
A heat generating portion provided at a position closer to the first ink supply path than the second ink supply path and generating heat;
With respect to the direction in which the first and second ink supply paths are arranged, the first and second ink supply paths are provided to the outside of the range where the heat generating portion is provided, and at least some of the ink supply paths including the first ink supply path are provided. And a transmission unit capable of transmitting heat of the heat generating unit. The printing apparatus according to claim 5,
The temperature controller is
A first heat generating part provided at a position closer to the first ink supply path than the second ink supply path;
A second heat generating part provided at a position closer to the second ink supply path than the first ink supply path,
The first heat generating unit removes ink in the first ink supply path so that the temperature of ink in the first ink supply path is higher than the temperature of ink in the second ink supply path. Heated,
The second heat generating unit may be configured so that the temperature of ink in a predetermined ink supply path other than the first ink supply path is lower than the temperature of ink in the first ink supply path. A printing device that heats ink in a supply path.

Images