1. Field of the Invention
The present invention relates to an image recording apparatus in which is mounted a recording head that performs recording by ejecting (discharging) a liquid from an energy generating element or by thermal transfer.
The present invention can be applied for apparatuses, such as printers, copiers, facsimile machines for which communication systems are provided, or word processors that incorporate printers, that perform the recording of images on a recording medium, such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood or ceramics, and for industrial recording apparatuses with which various processors are combined.
xe2x80x9cRecordingxe2x80x9d in this invention is defined not only as the formation on a recording medium of images, such as characters or drawings, that convey meaning, but also as the formation of images, such as patterns, that convey no meaning.
2. Related Background Art
Conventionally, the demand for recording apparatuses that can produce high quality images has increased, and how to improve image quality has been the subject of numerous discussions. For a recording apparatus in which a recording head is moved in one direction when recording images, the precision of the positioning of an image to be recorded is determined by the accuracy with which the recording head itself is positioned. And for the improvement of the image quality, the enhancement of the accuracy with which a recording head is positioned is an extremely important element. Therefore, in a conventional recording apparatus, for a carriage on which is mounted a recording head that records in only one direction, position detection means (e.g., an image scanner) is provided for accurately ascertaining the position of the recording head. Or, at the carriage""s home position in the apparatus, optical reading means is provided to detect the position of the recording head. Then, based-on the obtained head positioning data, whether the recording position is adequate or whether the recording position must be corrected is determined.
However, in a conventional recording apparatus the recording head, which constitutes the printing means, and the position detection means are arranged separately. Therefore, in a recording apparatus wherein, for example, a head position detection means is provided for a carriage, satisfactory positioning accuracy for the recording head must be obtained by mounting the recording head on the carriage. In order to obtain such accuracy, precision in the sizing of components, such as the carriage and the recording head, must be improved, or a process must be performed for correcting the positioning of the recording head.
In addition, since elements and circuits for detecting the position of the recording head must be formed on the carriage or on the substrate of the apparatus, manufacturing costs will be increased.
From the viewpoint of high quality image recording, highly delicate recording, for improved image density and tone representation, can be performed by producing dots that have variable sizes.
As the resolution of an image is increased, however, extremely high accuracy is needed to position the dots that are formed, and as the number of steps involved in varying the dot sizes is increased, greater dot size accuracy is required.
Thus, when a plurality of recording elements are employed, dot positioning errors and the use of non-uniform dot sizes can result in the deterioration of the image quality.
It is apparent that the demand for increased image quality can not be satisfied merely by improving the accuracy of the positioning of a carriage and a recording head and the accuracy in the production of dot sizes, so that accordingly, the shortcomings attributable to inaccurate dot positioning and to the unstable production of accurately sized dots are not resolved.
It is, therefore, one object of the present invention to provide at a low manufacturing cost an ink jet recording apparatus that can not only accurately detect the position of a recording head but can also accurately stabilize the positioning and the sizing of dots, a recording head therefor, and an element substrate to be used for the recording head.
To achieve the above object, according to one aspect of the present invention, provided is a recording head substrate on which are mounted energy generating elements that contribute to the formation of images by a recording head, and on which both light-receiving elements and light-emitting elements, or at least, light-receiving elements are mounted.
The light-receiving elements can be photodiodes or CCDs.
In addition, a controller for controlling the energy generating elements and the light-receiving elements is also mounted on the recording head substrate.
In this case, it is preferable that the light-receiving elements and at least one part of the controller be produced during the same manufacturing process.
The energy generating elements and the light-receiving elements are arranged along at least one line on the recording head substrate.
The energy generating elements and the light-receiving elements are arranged along a plurality of lines, and the lines are parallel to each other.
In this case, on the individual lines the number of the energy generating elements may be equal to the number of the light-receiving elements, but it is preferable that the number of the light-receiving elements be greater than the number of the energy generating elements.
According to one more aspect of the present invention, provided is a recording head comprising:
the above described recording head substrate;
a top board in which are formed liquid flow paths that correspond to the energy generating elements; and
discharge orifices (port) which is communicated with the liquid flow path of the top plate and through which liquid is discharged by the application of energy by the energy generating elements,
wherein the light-receiving elements and the light-emitting elements on the recording head substrate are optically opposite a face on which an image is formed by using the discharge ports.
According to the present invention, as is described above the energy generating elements and the light-receiving elements are mounted on the same substrate. Therefore, when the light-receiving elements optically detect dots formed by the energy generating elements, accurate information concerning the positioning, the sizes and the densities of the image dots can be obtained quickly. Further, since in contrast to an arrangement where the energy generating elements, the light-emitting elements and the light-receiving elements are mounted on separate substrates, the process for the formation of the individual elements can be commonly employed and no connections are required, the manufacturing cost and the size of an apparatus can be considerably reduced.
According to another aspect of the present invention, provided is a recording head substrate on which are mounted energy generating elements that contribute to the formation of images by a recording head, and on which are mounted a plurality of head position detecting elements for detecting the position of the recording head.
According to an additional aspect of the present invention, a recording head, for forming images using energy generating elements, comprises:
a substrate on which are mounted not only the energy generating elements but also a head position detecting element for detecting the position of the recording head.
According to a further aspect of the present invention, a liquid recording apparatus comprises:
a recording head for forming images employing energy generating elements while moving on a line;
head position detecting elements that are provided for the recording head for detecting the position of the recording head; and
a member in the recording apparatus that, in order to be detected by the head position detecting elements, is fixed opposite the head detecting element and along a track where the recording head moves.
The head position detecting elements are mounted on a substrate on which the energy generating elements are also mounted. In addition, it is preferable that, in accordance with position data for the recording head, detected by the head position detecting elements, and other recorded data, a circuit for generating signals to drive the energy generating elements, and light-receiving elements, for detecting an image that is formed, be mounted on the substrate on which the energy generating elements are mounted.
The head position detecting elements may be magnetic detecting elements, light-receiving elements or electric field detecting elements. The energy generating elements may be electro-thermal converting elements for heating liquid and inducing film boiling in order to discharge liquid droplets for forming images.
As is described above, according to the present invention, since the energy generating elements that contribute to image recording and the elements for detecting the position of the recording head are mounted on the same substrate, the accuracy at which the position of an image can be recorded is extremely high. In addition, since using semiconductor fabrication processing at least the elements having two functions can be mounted on the same substrate at the same time, the manufacturing costs can be drastically reduced.