JPH08244217A - Dot printer - Google Patents

Abstract

PURPOSE: To detect whether recording is accurately conducted or not according to the presence or absence of a dot on a recording medium. CONSTITUTION: A recording position and a reading position are separated by n dots. A recorded dot pattern is delayed by n dots by a shift register 207 according to a timing signal output from a timing generator 203 synchronized with a drive circuit 215, and input to a comparator 208. The data is photoelectrically converted by a photoelectric converter, amplified by amplifiers 209a to 209d, and input to a comparator 208. A coincidence signal of the comparison result of the comparator 208 is sent to a CPU 201 via an input port 206, and the CPU 201 judges whether the recording before the n dots are correctly conducted or not. When the comparison result of the comparator 208 is judged to be a mismatch, an error process is executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dot printer.

[0002]

2. Description of the Related Art Conventionally, as a typical dot printer, there is a wire dot printer which hits a wire on a paper surface for recording.

Further, there is an ink jet printer in which the ink is vaporized by heating a heater in the nozzle, and the pressure causes the ink droplet to fly, or the ink droplet to fly by contracting by a piezo element or the like to print. .

[0004]

However, in this type of dot printer, only some dots may be defective in recording.

In particular, in an ink jet printer, due to various factors such as ink drying, dirt on the nozzle surface, size of ink bubbles, and ink remaining amount detection, even if a recording operation is performed, recording is not accurately performed on recording paper. In some cases, it was unclear whether or not it was recorded correctly on the recording paper.

The present invention has been made in order to solve the above-mentioned drawbacks of the conventional example, and the purpose thereof is to detect whether or not recording is accurately performed by the presence or absence of dots on the recording medium. To provide a dot printer.

[0007]

A dot printer according to the present invention comprises a recording means for recording on a recording medium by a dot matrix system, and a reading means for reading a dot pattern actually recorded on the recording medium by this recording means. Holding means for holding the dot pattern to be printed by the printing means until the dot pattern read by the reading means can be compared, and the dot pattern read by the reading means for the dots held by the holding means. It is provided with a comparing means for comparing with the pattern, and a judging means for judging the recording failure when the outputs of the comparing means do not match.

[0008]

The dot pattern used by the recording means held by the holding means for recording and the dot pattern actually recorded on the recording medium by the recording means are compared by the comparing means, and when the comparison result does not match, the judging means Therefore, it is determined that the recording is defective. On the other hand, when the comparison results are in agreement, it is considered that the recording is normally performed.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a diagram showing a recording head of an ink jet printer according to Embodiment 1 of the present invention.

In this figure, 101 is a glass top plate, 1
Reference numeral 02 denotes an ink supply pipe for supplying ink to the recording head, 1
Reference numeral 03 is a face plate. 104 is a bubble that gives pressure to eject ink, 105 is a nozzle that ejects ink droplets, 106 is a heater element that heats the ink in the nozzle 105 to generate bubbles, and 107 is a nozzle hole that serves as an ejection port for ink droplets. is there. Reference numeral 108 is a silicon plate on which the heater element 106 and the circuit pattern are formed, and 109 is an aluminum base plate which provides the recording head with strength and also serves as a heat dissipation plate. 110 is a SELFOC lens array (registered trademark) that guides the ink on the recording surface for each dot (reads the presence or absence of the ink by a light amount value), and 111 is the SELFOC lens array 11
A photoelectric conversion element that photoelectrically converts the light guided by 0, and 112 is a substrate on which the photoelectric conversion element 111 and the like are formed.

In this embodiment, the recording position and the dot optical reading position are separated by n dots. That is, when the recording head (or recording paper) advances by n dots after recording, the dots are read and it is verified whether or not the recording was performed correctly.

FIG. 2 is a block diagram of the control circuit of this embodiment.

In this figure, 201 is a CPU for controlling the entire circuit, and 202 is an address decoder for selecting the address of input / output data. Reference numeral 203 denotes a timing generation circuit that creates various timings, and here, supplies timing for shifting recording information for each dot (direction in which the recording head advances). A data bus 204 exchanges data with a storage device (not shown). An output port 205 outputs a dot pattern to be printed. Reference numeral 206 is an input port for passing the result of comparing the dot pattern to be printed and the actually printed dot pattern by the comparator 208 to the CPU 201.

Numerals 207 _{1 to} 207 _n are n-bit shift registers for holding the recorded dot pattern up to a position where it can be compared with the dot pattern to be printed (in this embodiment, the printing position and the reading position are for n bits). They are far apart, but n = 0 is acceptable). Reference numeral 208 is a comparator that compares the dot pattern output before n bits with the dot pattern currently being read. 209 _a
˜209 _d is an amplifier that amplifies the signal photoelectrically converted by the photoelectric conversion element 111. 210 is the address decoder 2
02 is an address bus for sending address data.

Reference numerals 211 and 212 are selection signals for the output port 205 and the input port 206, respectively. 213 is a coincidence signal which is the output result of the comparator 208.

[0017] 214 _a ~214 _d is a driver to send the recorded information to the recording head. Reference numeral 215 is a drive circuit such as a motor (not shown) for driving the recording head.

Next, the operation will be described.

As described above, the recording position and the reading position are separated by n dots. The recorded dot pattern corresponds to the timing generation circuit 20 synchronized with the drive circuit 215.
3 is delayed by n dots in the shift register 207 according to the timing signal output from the comparator 208.
Is input to At this time, if the recording was done correctly,
This data is photoelectrically converted by the photoelectric conversion element 111, amplified by the amplifiers 209a to 209d, and then converted by the comparator 20.
It should agree with the data (actually recorded dot pattern on the reading position) input in 8.

The match signal 213, which is the comparison result of the comparator 208, is passed through the input port 206 to the CPU 20.
1 is sent to the CPU 201. Here, the CPU 201 determines whether or not recording before n dots has been correctly performed.

Then, the CPU 201 uses the comparator 2
When the comparison result in 08 is inconsistent, it is determined that the recording is defective.

In this way, it is possible to detect whether or not the recording has been performed accurately by the presence or absence of dots on the recording medium.

When the CPU 201 determines that the recording is defective, the following error processing is performed.

First, the nozzle that caused the recording failure can be identified from the above comparison result. Then, after all the recording is completed or after one line of recording is completed, the defective test is performed by the prepared test pattern (prepared for each nozzle and stored in the recording device (not shown)) for the nozzle specified here. Only the generated nozzles are automatically made to perform the recovery operation (the recovery operation itself is the same method as the conventional example except that some nozzles are executed).

As a result, the recovery operation can be performed without wasting ink, and the operability is also improved.

(Second Embodiment) FIG. 3 is a diagram showing a recording head of an ink jet printer according to a second embodiment of the present invention.

In the present embodiment, the optical fiber bundle 310 is used to guide the read data to the photoelectric conversion element 111.

The rest of the configuration and operation are the same as in the first embodiment, so the explanation is omitted.

[0029]

As described above, according to the dot printer of the present invention, it is possible to detect whether or not recording is accurately performed by the presence or absence of dots on the recording medium.

[Brief description of drawings]

FIG. 1 is a diagram showing a recording head according to a first embodiment.

FIG. 2 is a block diagram of a control circuit according to the first embodiment.

FIG. 3 is a diagram showing a recording head according to a second embodiment.

[Explanation of symbols]

 111 photoelectric conversion element 201 CPU 205 output port 206 input port 207 shift register 208 comparators 214a to 214d driver

Claims (1)

[Claims] 1. A recording unit for recording on a recording medium by a dot matrix system, a reading unit for reading a dot pattern actually recorded on the recording medium by the recording unit, and a dot to be recorded by the recording unit. Holding means for holding the pattern until it can be compared with the dot pattern read by the reading means, comparing means for comparing the dot pattern read by the reading means with the dot pattern held by the holding means, and this comparing means. And a determination unit that determines that the recording is defective when the outputs of the two do not match.