Patent Application
20190248133
The present invention relates to a multilayer structured element substrate, a printhead, and a printing apparatus, and particularly to, for example, a printing apparatus that employs a printhead which incorporates a plurality of multilayer structured element substrates including a plurality of print elements to perform printing in accordance with an inkjet method.
There is known a thermal driving method of printing by arranging an electrothermal transducer (heater) in a portion that communicates with each orifice which discharges an ink droplet in an inkjet printhead, and causing ink droplets to be discharged onto a print medium by ink film boiling by supplying an electric current to heat each heater. In this arrangement, the printing apparatus transmits desired signals to an element substrate including a plurality of heaters, and a current is supplied to each heater by operating a corresponding driving circuit.
In recent years, a full-line printhead that has an arrangement in which a plurality of element substrates are arranged across a print width has become popular for commercial and industrial purposes. High-speed printing is possible when a full-line printhead is used because only the print medium needs to be conveyed. Japanese Patent Laid-Open No. 2010-012795 discloses an arrangement in which each element substrate is arranged so as to be offset vertically with respect to an orifice array direction between the connecting portions of adjacent element substrates. In addition, there is also an arrangement which allows the element substrates to be arranged in line by vertically offsetting the orifice array in each element substrate.
In addition, there is proposed a printing apparatus that uses, instead of a full-line printhead, a printhead that has an arrangement in which two or more element substrates are arranged adjacently to increase the printing length in one scan printing operation. In this case, even if printing is to be performed by reciprocally scanning a carriage including the printhead, the number of the carriage scan operations performed until the completion of printing can be reduced because the print width of the printhead is long.
In order to reduce the production cost of an element substrate, size reduction of the element substrate is required. Particularly, in an arrangement in which a plurality of element substrates are connected and arranged in a single array as described above, the size of the element substrate needs to be reduced for also the following reason.
A plurality of heater arrays (five heater arrays in this case) formed by a plurality of heaters 101 are arranged parallel to each other in each element substrate 100. In addition, dummy heaters 201 are arranged at the respective ends of each heater array. Hence, a heater 101a at the end of each heater array forms a connecting portion with a heater 101b at the end of a corresponding heater array of an adjacent element substrate.
However, the above-described related art has the following problem.
Since the connecting portion of each element substrate 100 has a shape having an angle with respect to the x direction, if the circuit 302 to be arranged at the end of each heater array is large, the size of the element substrate will increase due to the constraint of the outer shape of the element substrate, and thus the length between the connecting portions of the adjacent element substrates will increase. If the length between connecting portions is long, it can create a difference in an air flow strength generated by the conveyance of the print medium between the orifices on the upstream side and the orifices on the downstream side in the conveyance direction of the print medium in the connecting portion, and the printing quality will degrade due to the shifting of the ink landed position.
Hence, since this difference becomes more evident when the conveyance speed of the print medium is increased to increase the printing speed, the heaters arranged at the connecting portions formed between the element substrates need to be arranged close to each other as much as possible.
Accordingly, the present invention is conceived as a response to the above-described disadvantages of the conventional art.
For example, a multilayer structured element substrate according to this invention is capable of reducing its size. In addition, a printhead and a printing apparatus according to this invention are capable of performing high quality printing even in a case in which a plurality of the element substrates are arranged in one array.
According to one aspect of the present invention, there is provided a multilayer structured element substrate comprising: an element array in which a plurality of print elements are arranged and a dummy element not contributing to printing is included; and a first circuit related to driving the plurality of print elements forming the element array, wherein the dummy element and the first circuit are arranged at a position where the dummy element and the first circuit at least partially overlap each other in a planar view of the element substrate.
According to another aspect of the present an invention, there is provided a printhead in which a plurality of the element substrates having the above-described arrangement are arranged along an element array direction and print elements are driven to discharge ink.
According to still another aspect of the present invention, there is provided a printing apparatus that prints an image by discharging ink onto a print medium by using a printhead which has the above-described arrangement.
According to still another aspect of the present invention, there is provided a multilayer structured element substrate comprising: an element array in which a plurality of print elements are arranged and a dummy element not contributing to printing is included; and a plurality of circuits configured to drive the plurality of print elements and the dummy element, respectively, wherein, among the plurality of circuits, an area of a circuit configured to drive the dummy element is smaller than an area of a circuit configured to drive the print element.
According to still another aspect of the present invention, there is provided a printhead in which a plurality of the element substrates having the above-described arrangement are arranged along an element array direction and print elements are driven to discharge ink.
According to still another aspect of the present invention, there is provided a printing apparatus that prints an image by discharging ink onto a print medium by using a printhead which has the above-described arrangement.
The invention is particularly advantageous since the size of an element substrate can be reduced. In addition, the invention has an effect of reducing the length between print elements arranged at the ends of respective element substrates forming the connecting portions of adjacent print elements. This can contributes to improving the image quality of an image to be printed by the printhead.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Exemplary embodiments of the present invention will now be described in detail in accordance with the accompanying drawings.
In this specification, the terms “print” and “printing” not only include the formation of significant information such as characters and graphics, but also broadly includes the formation of images, figures, patterns, and the like on a print medium, or the processing of the medium, regardless of whether they are significant or insignificant and whether they are so visualized as to be visually perceivable by humans.
Also, the term “print medium (or sheet)” not only includes a paper sheet used in common printing apparatuses, but also broadly includes materials, such as cloth, a plastic film, a metal plate, glass, ceramics, wood, and leather, capable of accepting ink.
Furthermore, the term “ink” (to be also referred to as a “liquid” hereinafter) should be broadly interpreted to be similar to the definition of “print” described above. That is, “ink” includes a liquid which, when applied onto a print medium, can form images, figures, patterns, and the like, can process the print medium, and can process ink. The process of ink includes, for example, solidifying or insolubilizing a coloring agent contained in ink applied to the print medium.
Further, a “print element (or nozzle)” generically means an ink orifice or a liquid channel communicating with it, and an element for generating energy used to discharge ink, unless otherwise specified.
An element substrate for a printhead (head substrate) used below means not merely a base made of a silicon semiconductor, but an arrangement in which elements, wirings, and the like are arranged.
Further, “on the substrate” means not merely “on an element substrate”, but even “the surface of the element substrate” and “inside the element substrate near the surface”. In the present invention, “built-in” means not merely arranging respective elements as separate members on the base surface, but integrally forming and manufacturing respective elements on an element substrate by a semiconductor circuit manufacturing process or the like.
<Printing Apparatus Including Full-Line Printhead (
In the printing apparatus 1, a print sheet 15 is supplied from a feeder unit 17 to the respective printing positions of these printheads and is conveyed by a conveyance unit 16 included in a housing 18 of the printing apparatus.
To print an image onto the print sheet 15, the print sheet 15 is conveyed, and black (K) ink is discharged from the printhead 11K when the reference position of the print sheet 15 has reached a position under the printhead 11K that discharges black ink. In the same manner, corresponding color inks are discharged when the print sheet 15 reaches the reference positions of the printhead 11C that discharges cyan (C) ink, the printhead 11M that discharges magenta (M) ink, and the printhead 11Y that discharges yellow (Y) ink, respectively, thereby forming a color image. The print sheet 15 on which an image has been printed in this manner is discharged to a stacker tray 20 and stacked.
The printing apparatus 1 further includes the conveyance unit 16 and an exchangeable ink cartridge (not shown) for each ink to supply ink to each of the printheads 11K, 11C, 11M, and 11Y In addition, the printing apparatus further includes a pump unit (not shown) for supplying ink to and for performing recovery operation on each of the printheads 11K, 11C, 11M, and 11Y and a control substrate (not shown) for controlling the overall printing apparatus 1, and the like. A front door 19 is a door that can be opened and closed to exchange each ink cartridge.
A printhead 11 according to this embodiment employs an inkjet method of discharging ink by using thermal energy. Hence, the printhead includes an electrothermal transducer (heater). The electrothermal transducer is arranged in correspondence with each orifice, and ink is discharged from the orifice when a pulse voltage is applied to the corresponding electrothermal transducer in response to a print signal. Note that the printing apparatus is not limited to a printing apparatus using a full-line printhead that has a print width which corresponds to the width of a print medium as described above. The present invention is applicable to, for example, a so-called serial-type printing apparatus that includes, on a carriage, a printhead with orifices arranged in the conveyance direction of a print medium and performs printing by discharging ink onto the print medium while reciprocally scanning this carriage.
<Description of Control Arrangement (
The control arrangement for executing print control on the printing apparatus described with reference to
The operation of the aforementioned control arrangement will be described. When print data is input to the interface 1700, the print data is converted, between the gate array 1704 and the MPU 1701, into a print signal for printing. Printing is performed by driving each printhead in accordance with the print data transmitted to the head driver 1705 together with the driving of the motor driver 1706. Also, the transfer error (to be described later) information obtained from each printhead is fed back to the MPU 1701 via the head driver 1705, and the information is reflected on print control.
As shown in
Each of the printheads 11K, 11C, 11M, and 11Y includes an element substrate including a plurality of heaters and their driving circuits each arranged in the manner shown in
In a printhead 11, a signal is transferred and power is supplied from the printing apparatus 1 to a connector 35, and the signal and the power are connected to each pad 33 of the element substrate 100 via a corresponding head wiring 34. The printhead 11 which includes four element substrates 100 will be exemplified here. On each element substrate 100, the heaters 101 are arranged across a plurality of arrays (four arrays in this case). In each element substrate 100, of the sides forming the outer shape of the element substrate 100, each side positioned near the adjacent element substrate 100 extends in a direction intersecting with the heater array direction. In
The arrangement shown in
By making the connecting portions of the element substrates have an angled shape and arranging the element substrates linearly in the above described manner, the length between the heaters of the connecting portions of adjacent element substrates can be shorter than those of a case in which the element substrates are arranged in a staggered manner.
Several embodiments related to element substrates mounted on a printhead included in a printing apparatus with the above-described arrangement will be described next.
As shown in
A nozzle arranged in correspondence with each heater may be arranged on the dummy heater to improve the stability of its shape. Since a supply port 105 and a MOS transistor 103 need not be arranged for the dummy heater 201, a timing adjustment circuit 301 that adjusts the timings of a clock signal CLK and a data signal DATA which are transferred from the x-direction plus side is arranged immediately below the dummy heater 201. Note that “immediately below the dummy heater 201” indicates a state in which the circuit is arranged at a position where the dummy heater 201 and the timing adjustment circuit 301 partially overlap each other in a planar view of the element substrate 100. Note that, in order to reduce the area of the element substrate, it is preferable to arrange the dummy heater 201 within the region of the timing adjustment circuit 301 in a planar view of the element substrate as shown in
The clock signal CLK and the data signal DATA whose phases have been adjusted by the timing adjustment circuit 301 are output to the x-direction minus side, and are transmitted to the timing adjustment circuit of each adjacent heater array. The clock signal CLK and data signal DATA are also input to each selection circuit 104. Each selection circuit 104 is formed from a shift register circuit and a latch circuit that transfer the data signal DATA, and transfers driving data to the MOS transistor of the corresponding heater. The clock signal CLK and the data signal DATA input from each pad of the element substrate 100 are internally processed in the element substrate 100 and transferred to each heater array. However, since a phase difference will be generated between the clock signal CLK and the data signal DATA if the transfer length is long, the timing adjustment circuit 301 is arranged in the middle in this embodiment.
Since the timing adjustment circuit 301 adjusts the timings of the clock signal CLK and the data signal DATA and transfers the adjusted clock signal CLK and the adjusted data signal DATA to the selection circuits 104 of each heater array, the timing adjustment circuit 301 is arranged at the end of each heater array. In this embodiment, particularly, by arranging the timing adjustment circuit 301 immediately below the dummy heater, the timing adjustment of the clock signal CLK and the data signal DATA to be transmitted to the corresponding heater array is performed at the end of the array. In addition, by arranging the timing adjustment circuit 301 immediately below the dummy heater at the end of each heater array, each timing adjustment circuit 301 is connected to a clock signal line and a data signal line arranged at the end of the element substrate 100. These timing adjustment circuits 301 are connected to a control circuit (not shown) via these signal lines.
Note that a circuit to be arranged immediately below the dummy heater 201 is not limited to the timing adjustment circuit 301, and a decoder or the like may be arranged.
An arrangement including a decoder will be described as another example of a circuit to be arranged below each dummy heater 201. Since the circuit area will increase if the shift register circuit and the latch circuit of the selection circuit 104 are arranged for each heater, an arrangement in which the plurality of heaters of a heater array are divided into time-divisional drive groups is adopted. In this kind of an arrangement, a desired heater is selected by obtaining AND of the driving data for each group and the driving data for each time-divisional driving operation. In this case, the decoder expands the data signal DATA used for the time-divisional driving operation and transmits the data signal DATA for selecting only the heaters of the selected group. Since this decoder is arranged at the first stage or the end stage of the shift register circuit, it will be arranged at the end of the heater array.
In this manner, since a circuit for integrally processing the operations of one array of heaters is required to be arranged at the end of this heater array, it is possible to reduce the arrangement area by arranging this circuit immediately below the dummy heater which is arranged at the end of the heater array. Note that this circuit need not be a circuit that processes the operations of all of the heaters included in one heater array, and suffices to be a circuit for processing the operations of the plurality of heaters included in the one heater array.
As is obvious from the above description, the element substrate 100 has a multilayer structure. An arrangement in which two wiring layers and a layer for arranging the heaters formed on the two wiring layers will be described here.
As shown in
The x-direction minus side of the heater 101 is connected to a driving power supply via a via 110a and the wiring layer 107, and the x-direction plus side of the heater 101 is connected to a MOS transistor 103 via a via 110b, the wiring layer 107, a via 110c, and a wiring 102. The wiring layer 106, the wiring layer 107, and a via 110d connecting these layers are arranged immediately below the heater 101 to improve heat dissipation at the time of a driving operation. The wiring layers 106 and 107 for heat dissipation which are arranged immediately below the heater 101 each have a comparatively large surface area and are not connected to the heater 101.
Immediately below the dummy heater shown in
By adopting such an element substrate structure, even if the dummy heater 201 is arranged, the size of the element substrate can be reduced while avoiding a state in which an integrated circuit interferes with the outer shape of the element substrate 100 by arranging the circuit immediately below the dummy heater. In addition, the length between the connecting portions of adjacent element substrates can be shortened because the heater 101 that contributes to printing at the end of the heater array can be brought closer to the periphery of the element substrate 100. As a result, it is possible to reduce the ink droplet land position shift amount due to the air flow caused by the conveyance of the print medium at printing and suppress ink land position shift even when the print medium is conveyed skewed with respect to the heater array.
As is obvious from comparing
As is obvious from comparing
Other examples of the shape of the element substrate will be described here.
Although a parallelogram shape as that shown in
In
As described above, the shape of the element substrate and the direction of the heater arrays can be combined in various kinds of ways to form an arrangement.
Hence, according to the above-described embodiment, the size of the element substrate can be reduced by arranging a logic circuit such as the timing adjustment circuit immediately below the dummy heater at the end of each heater array. In addition, it is possible to reduce the length of the connecting portions between adjacent element substrates, reduce the ink land position shift amount due to the air flow caused by the conveyance of the print medium during a printing operation, and suppress the ink land position shift even when the print medium is conveyed skewed with respect to the heater array. As a result, high-quality image printing can be achieved.
Note that although the above-described embodiment has described an example in which one dummy heater is arranged at the end of each heater array, the present invention is not limited to this. A plurality of dummy heaters may be arranged.
In addition, the circuit arranged immediately below the dummy heater need not be only the timing adjustment circuit or the decoder. For example, there is an arrangement in which a detection element for detecting temperature information in correspondence with each heater of the heater array is used, and a detection element array formed by arranging the detection elements is arranged for each heater array. It is possible to identify the discharge failure of an orifice based on the detection result of the detection element and reflect this information to a complementary image print operation or to a head recovery job. The detection element is, therefore, a circuit indirectly related to driving control of the heaters. The circuit to be arranged immediately below the dummy heater can be a reference voltage source, a reference current source, and the like in this detection element circuit. That is, the circuit to be arranged immediately below the dummy heater is not limited to a circuit directly related to driving the heaters of the heater array and suffices to be a circuit related to the driving control of the heaters of the heater array. In addition, the same circuit need not be always arranged for all of the heater arrays, and different circuits may be arranged.
Furthermore, dummy heaters may be arranged at both ends of each heater array, and a circuit for driving a plurality of heaters included in the heater array may be arranged immediately below each of the dummy heaters at both ends. In this case, circuits that have different functions from each other may be arranged immediately below the dummy heaters at the respective ends. For example, the timing adjustment circuit may be arranged immediately below the dummy heater at one end of the heater array, and the decoder may be arranged immediately below the dummy heater at the other end of the heater array. By arranging different circuits at the ends, the areas required for the respective circuits can be ensured, and the size of the element substrate can be further reduced.
Note that there may be a case in which it is possible to perform processing without arranging the timing adjustment circuit for every heater array. In such a case, the timing adjustment circuit can be arranged immediately below each of the dummy heaters included in some of the heater arrays, and the timing adjustment circuit need not be arranged immediately below each of the dummy heaters included in the remaining heater arrays.
In addition, although an arrangement in which the dummy heater is arranged at the end of the heater array has been described, the position of the dummy heater is not limited to the end of the heater array, and the dummy heater may be arranged in the middle of the heater array. In this arrangement as well, the area of the element substrate can be reduced by arranging the circuit for driving a plurality of print elements included in the heater array immediately below the dummy heater.
In this embodiment, in order to use each dummy heater 201 in the preliminary discharge operation, a supply port 205, a MOS transistor 203, and a selection circuit 204 are included in correspondence with the dummy heater 201 in the same manner as the heater 101. Each dummy heater 201 is connected to the corresponding MOS transistor 203 by a wiring 202. The selection circuit 204 transmits a dummy heater selection signal to control the ON/OFF of the MOS transistor 203. As a result, an electric current flows to the dummy heater 201, and ink is discharged by this energy.
Since the dummy heater 201 is not used to perform printing on a print medium, there is no need to strictly control its discharge characteristics compared to the heater 101. Hence, the MOS transistor 203 corresponding to the dummy heater 201 can have a lower driving capability than a MOS transistor 103 corresponding to the heater 101. That is, it becomes possible to reduce the circuit size on the x-direction minus side by reducing the gate width of the MOS transistor 203. The position of the selection circuit 204 can be shifted to the x-direction minus side in correspondence with this reduction. A clock signal CLK and a data signal DATA to be used for the selection circuit 204 are transmitted from a selection circuit 104 as shown in
It is possible to reduce the size of the element substrate by downsizing the MOS transistor 203 corresponding to the dummy heater 201 by using the above-described arrangement. In addition, the length between the connecting portions of the adjacent element substrates can be reduced because the heater 101 that contributes to printing at the end of each heater array can be brought closer to the periphery of the element substrate 100. As a result, the ink land position shift amount due to an air flow caused by the conveyance of the print medium during the printing operation can be reduced, and the ink land position shift can be suppressed even in a case in which the print medium is conveyed skewed with respect to the heater array.
Also, as shown in
In addition, as shown in
First, in a case in which the transistor is reduced by a length a in the x direction, the circuit shape of a MOS transistor 203a is increased by a length b from the side 211 of the outer shape oblique with respect to the y direction to the circuit end. In contrast, in a case in which the transistor is reduced by the length a in the y direction, the circuit shape of a MOS transistor 203b is increased by a length c from the side 211 of the outer shape oblique with respect to the y direction to the circuit end. As is obvious from
Hence, in a case in which the element substrate angle θ is equal to or larger than 45° (θ≥45), a greater size reduction effect can be obtained by performing reduction in the x direction more than in the y direction because the element substrate size can be reduced more. On the other hand, in a case in which the element substrate angle is smaller than 45° (θ<45), a greater size reduction effect can be obtained by performing reduction in the y direction more than in the x direction because the element substrate size can be reduced more.
As is obvious from comparing
As is obvious from comparing
Hence, according to the above-described embodiment, the size of the element substrate can be reduced by reducing the MOS transistor corresponding to the dummy heater in the x direction or the y direction. In addition, it is possible to reduce the length between the connecting portions of adjacent element substrates, reduce the ink land position shift amount due to the air flow caused by the conveyance of the print medium during a printing operation, and suppress the ink land position shift even when the print medium is conveyed skewed with respect to the heater array. As a result, high-quality image printing can be achieved in the same manner as the first embodiment.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2018-025352, filed Feb. 15, 2018, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-025352 | Feb 2018 | JP | national |
