JP4086540B2 - Contact-type transceiver - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a contact type transmission / reception apparatus that performs data communication.
[0002]
[Prior art]
In recent years, information management such as quality and distribution has been performed by storing individual information for a huge number of products, etc., communicating with them and rewriting information, etc. .
[0003]
In this way, small-sized transmission / reception devices (elements) capable of rewriting data are not limited to commercial products in the future, but are used as personal ID cards for medical and administrative purposes, or as securities such as electronic money. Various applications are expected.
[0004]
Considering the number of individuals, the environment in which they are used, etc., it is desirable that the device added to each individual should have a simple internal circuit configuration from the viewpoint of miniaturization and cost reduction and durability. Similarly, it is expected that the convenience of these information management systems will be improved by simplifying the transmission / reception devices that communicate with them.
[0005]
Communication means between each individual and the transmission / reception apparatus is classified into contact type (wired system) and non-contact type (wireless system) communication means in terms of the intended use. Since the contact-type communication means does not require the electromagnetic inductive coupling device used in the non-contact-type communication means, low cost is realized. The contact type communication means differs in the configuration of the internal circuit and the number of necessary communication signal lines depending on the communication method, but the configuration with two signal lines that can minimize the number of parts is the cheapest. . An example of the configuration of a contact-type transmitting / receiving device having two signal lines is shown in FIG.
[0006]
A contact type transmission / reception device (referred to as a memory chip 6) that does not require a power source and is attached to the cartridge 3 includes two contact electrodes 10 corresponding to two signal lines, and a signal connected to the driving device 2 in the printer device 1. The line 4 and the signal line 5 are brought into contact with the contact electrode 10 of the memory chip 6 through the two contacts on the contact connector 8, that is, the contact terminals 7, to ensure conduction.
[0007]
There are several communication methods in the configuration with the two signal lines, and an example will be described with reference to FIGS. In the drive circuit 2 of FIG. 7, the modulation signal generator 12 modulates the carrier signal SA (FIG. 9C) based on the data signal SB to generate the modulation signal SC (FIG. 9A), and the signal line 4 Sent over. Here, the signal line 5 is used as the signal ground 25 (0 V) which becomes the reference potential of the modulation signal SC. The signal ground 25 is grounded to the frame ground of the printer apparatus 1.
[0008]
On the other hand, in the memory chip 6 (FIG. 8), the signal line 5 is set as a reference potential, and the modulation signal SC from the signal line 4 is demodulated into the data signal SB in the rectifier 14. An example of the demodulated signal is shown in FIG. By connecting and charging the voltage holding capacitor 16 as shown in FIG. 9, it is possible to prevent the voltage from instantaneously becoming 0V when the carrier signal SC is switched, and the memory chip 6 always has a voltage of VL volts (> 0) or more. (See FIG. 9B). This is a power supply source for the memory chip 6 that does not have a power source.
[0009]
When the memory chip 6 receives a control command for reading from the drive circuit 2 (FIG. 7) (ie, transmission from the memory chip 6 to the drive circuit 2), the signal SE read from the storage unit 17 is sent to the drive circuit 2. Send.
[0010]
This operation will be described in more detail. First, during communication, the carrier signal SB (FIG. 9C) is always transmitted to the memory chip 6 in order to synchronize from the drive circuit 2. When data is transmitted from the memory chip 6 to the drive circuit 2, the transmission data SB of the drive circuit 2 is previously stopped by a control command and is set to a constant voltage (VC). In this state, transmission to the drive circuit 2 is performed by the modulation unit 19 (FIG. 8). The modulation unit 19 includes an impedance element 20 and a switch element 21 that are sufficiently small (for example, about 1/10) with respect to the input impedance of the memory chip 6, and is inserted between the signal line 4 and the signal line 5. Yes.
[0011]
When the switch element 21 of the modulation unit 19 is controlled to be turned on / off based on the transmission signal SG, the input impedance of the memory chip 6 changes, and the voltage amplitude of the modulation signal SC that is in the non-modulated state is shown in FIG. As shown in (D), a binary value (VC, VD: corresponding to data 0 and 1) changes, and a signal that changes in this binary value is transmitted on the signal line 4.
[0012]
When the signal having the voltage amplitude shown in FIG. 9D, that is, the reception signal SH is received from the signal line 4 by the reception unit 13 of the driving circuit 2, the voltage change of the reception signal SH is detected by the reception unit 13. The received data SI is transmitted to the main control unit 11.
[0013]
[Problems to be solved by the invention]
Thus, in order to perform synchronous communication while supplying power with the signal line 5 as a reference potential, at least two signal lines are required. Therefore, it is difficult to reduce the cost by further reducing the number of signal lines. there were.
[0014]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a contact type transmission / reception apparatus capable of solving the above-described problems and reducing the cost by reducing the number of signal lines for communication to one.
[0015]
[Means for Solving the Problems]
The invention of claim 1 includes a connection portion detachable cartridge in the printer is in contact receiving apparatus for performing storage and data communication of the cartridge in a state of being attached to the printer, which is in contact with the contacts of the memory device, one and a signal line connected to the connecting part in order to perform the data communication with the storage device, coupled to said signal line, a drive circuit for sending data to the signal lines, the printer operation A high-voltage circuit for applying a high voltage to the cartridge , and a high-voltage circuit connected to a drum ground for discharging the charge of the photosensitive drum of the cartridge, the storage device and the drum ground connected, to connect the drum grounding to the frame ground of the printer, the signal ground of the drive circuit connected to the frame ground, Data communication is performed using the signal line with the drum ground potential as a reference potential, and the data communication is not performed when the high-voltage circuit or the photosensitive drum is operating and discharging the charge on the photosensitive drum, The data communication is performed when the high-voltage circuit or the photosensitive drum is stopped and the discharge of the charge of the photosensitive drum is finished .
According to a second aspect of the present invention, in the contact-type receiving device according to the first aspect, the storage device is configured such that when the cartridge is inserted into the printer or when the cartridge is removed from the printer. A filter for preventing noise flowing into the signal line when the contact point is connected to the connecting portion and the drum ground and the rotating shaft of the photosensitive drum are not grounded Further comprising a circuit.
According to a third aspect of the present invention, in the contact-type receiving device according to the second aspect, a coupling capacitor is provided between the contact circuit and the filter circuit.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0022]
<Configuration of contact-type transmitting / receiving device of embodiment>
FIG. 1 shows an embodiment of the present invention. This is an example of a contact type transmission / reception device provided in a printer.
[0023]
As an external device to be communicated, the memory chip 6 provided in the cartridge 3 and having no power source is used, but it is naturally applicable to a memory chip having a power source. The memory chip 6 is connected to the drive circuit 2 via the signal line 4, and data transmission / reception is performed with the drive circuit 2.
[0024]
Consumables and accessory devices are removable. A contact electrode 10 is provided on the memory chip 6 on the cartridge 3 to perform contact type transmission / reception. On the other hand, the drive circuit 2 is terminated by a contact connector 8 in order to connect the signal line 4 to the memory chip 6. The contact connector 8 has a contact terminal 7 for making contact with the contact electrode 10. With the above configuration, a detachable contact type transmitting / receiving device can be realized.
[0025]
As shown in FIG. 2, during printing, the photosensitive drum 27 in the cartridge 3 is charged via the charging roller 28 by the operation of the high voltage circuit 31. In order to discharge this electric charge, the drum ground 9 is connected to a frame ground 24 constituted by sheet metal (having conductivity) of the printer 1 or the like. On the other hand, also in the drive circuit 2, the signal ground 25 is grounded to the frame ground 24 of the printer 1. Therefore, the signal ground 25 of the drive circuit 2 and the potential of the drum ground 9 are the same. By using this drum ground 9, a common reference is provided without providing a signal line between the cartridge 3 and the drive circuit 2. A potential can be used.
[0026]
The memory chip 6 receives a signal from the drive circuit 2 with the drum ground 9 as a reference potential. Conventionally, it has been necessary to transmit the signal ground 24 using the signal line as a reference potential. However, according to the present invention, the ground signal line is not necessary, and the number of signal lines can be reduced.
[0027]
Therefore, the contact terminals and signal lines associated therewith can be reduced, the size of the contact electrodes and contact connectors on the memory chip 6 can be reduced and simplified, leading to cost reduction.
[0028]
As described above, it has been shown that the number of signal lines can be reduced according to the present invention. In the present embodiment, an example in which serial communication is performed using one signal line will be described in detail below.
[0029]
(Modulation signal transmission from the drive circuit)
FIG. 3 shows the configuration of the drive circuit 2 of FIG. The main control unit 11 generates a carrier signal SA having a cycle Tclk [sec] as shown in FIG. On the other hand, the data signal SB transmitted from the drive circuit 2 to the memory chip 6 has a transfer speed of 1 / Tclk [bps] or less as shown in FIG. The modulation signal generator 12 superimposes the data signal SB as an amplitude component on the carrier signal SA. As a result, a modulation signal SC that oscillates at a period Tclk is generated. This is transmitted using the drum ground potential as a reference potential. The example of FIG. 5A is a modulation signal SC transmitted from the drive circuit 2 to the memory chip 6.
[0030]
(Signal reception at the memory chip 6)
The modulation signal SC transmitted from the drive circuit 2 is received by the memory chip 6. FIG. 4 shows the configuration of the memory chip 6. The amplitude component of the modulation signal SC is extracted by the rectification unit 14 built in the memory chip 6, the data signal SB shown in FIG. 5B is demodulated, and the L level signal (voltage VL) holds a certain voltage or higher. Therefore, the sub control unit 15 can use this as a power source. Here, a voltage holding capacitor 16 is inserted in order to prevent a voltage drop at the rise and fall of the modulation signal SC. The demodulated data signal SB includes a control command sent from the drive circuit 2 in addition to the write data. Based on this, the sub-control unit 15 controls the entire memory chip 6 and writes and reads data to and from the storage unit 17 formed of a nonvolatile memory or the like according to the control command. These control and communication timings can be synchronized with the synchronization signal SD obtained from the modulation signal SC by the clock detection unit 18.
[0031]
(Transmission from the memory chip 6 to the drive circuit 2)
When a read control command is received from the drive circuit 2, the signal SE read from the storage unit 17 is transmitted to the drive circuit 2. This transmission means will be described. First, in order to synchronize from the drive circuit 2 during communication, a carrier signal SB as shown in FIG. 5C is constantly transmitted to the memory chip 6. Further, when data is transmitted from the memory chip 6 to the drive circuit 2, the transmission data SB of the drive circuit 2 is previously stopped by a control command, and is set to a constant voltage (VC). In this state, transmission to the drive circuit 2 is performed by the modulation unit 19 in the memory chip 6.
[0032]
The modulation unit 19 includes an impedance element 20 and a switch element 21 that are sufficiently small (for example, about 1/10) with respect to the input impedance of the memory chip 6, and these are inserted between the signal line and the drum ground potential. Yes. By turning the switch element 21 on and off based on the transmission signal SG, the input impedance of the memory chip 6 changes, and as a result, the modulated signal SC that has not been modulated has a voltage as shown in FIG. The amplitude changes binary (VC, VD), which correspond to 0 and 1 of the data. When this signal is a received signal SH, a voltage change is detected from the signal SH by the receiving unit 13 of the drive circuit 2 and transmitted to the main control unit 11 as received data SI. The above is an example of serial communication. In this way, communication is possible even with one signal line.
[0033]
(Communication timing)
The drum ground 9 is originally grounded in order to discharge the electric charge charged on the photosensitive drum in the cartridge 3. In addition, other consumables and accessory devices of the cartridge may discharge noise such as static electricity through the ground potential. When the drum ground 9 is used as a reference potential, the data communication may become unstable due to the discharge noise. In the present embodiment, it is possible to avoid the influence of discharge noise by limiting the timing of communication to the time when the photosensitive drum is not discharged.
[0034]
The discharge is performed during the printing operation, that is, when the high voltage circuit 31 (FIG. 2) is operating. Even if the high-voltage circuit 31 is stopped, static electricity due to friction is discharged during the rotation of the photosensitive drum, so data communication is not performed at this time. As a result, the drum ground 9 can be used as a more stable reference potential.
[0035]
(Prevents inflow of electrostatic noise into the drive circuit 2)
Next, the case where the ground of the drum ground 9 is disconnected from the frame ground 24 of the printer 1 will be described. While the cartridge 3 is mounted on the printer 1, the contact terminal 7 and the contact electrode 10 may remain in contact with each other, and the drum ground 9 may not be grounded to the frame ground 24 of the printer 1.
[0036]
As an example, when the cartridge 3 is inserted into the printer 1, the contact terminal 7 and the contact electrode 10 come into contact with each other, but the drum ground 9 of the cartridge 3 is not grounded until the coupling 26 of the rotating shaft shown in FIG. Therefore, during this time, the photosensitive drum 27 may be charged due to the operation of the high-voltage circuit 31, or static electricity may be generated due to the rotation, and this charge flows into the drive circuit 2.
[0037]
Even after the coupling 26 is engaged, if the cartridge 3 is removed from the drum ground 9 during discharge, only the ground of the drum ground 9 may be disconnected first. As described above, when only the ground of the drum ground 9 is disconnected, discharge noise may flow into the drive circuit 2 regardless of whether the communication is stopped or the communication is stopped, which may cause adverse effects such as destruction.
[0038]
In this embodiment, as shown in FIG. 1, noise inflow is prevented by providing a filter circuit 22 between the drive circuit 2 and the memory chip 6. Inflow of discharge noise can be prevented by providing a low-pass filter or a band-pass filter that allows only the communication frequency component to pass in the noise frequency band in the signal transmission path between the drive circuit 2 and the memory chip 6. .
[0039]
In addition to the filter circuit 22, as shown in FIG. 1, by inserting a coupling capacitor 23 between the drive circuit 2 and the memory chip 6, the charge is absorbed and discharge noise flows into the drive circuit 2. Can be prevented.
[0040]
The example of the contact type data communication using the drum earth of the cartridge in the printer has been described above. However, the present invention can be applied to a removable device other than the cartridge, for example, an accessory such as a paper feed cassette.
[0041]
【The invention's effect】
As described above, according to the present invention, since it is configured as described above, the number of signal lines for communication can be reduced to one, and serial communication can be performed with one signal line. Therefore, the number of parts such as contact terminals and contact electrodes can be minimized, and the cost and space can be reduced.
[0042]
Further, according to the present invention, when using the drum ground as a reference potential for data communication, the communication timing is limited to non-discharge of the drum ground, so that stable data communication can be performed without being affected by discharge noise. It can be carried out.
[0043]
Furthermore, according to the present invention, since the filter circuit and the coupling capacitor are inserted on the transmission path of the data signal, when the connection between the drum ground and the frame ground is disconnected, the discharge noise from the drum ground is a signal. Inflow to the wire side can be prevented.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of the cartridge 3 of FIG.
3 is a block diagram showing a configuration of a drive circuit 2 in FIG. 1. FIG.
4 is a block diagram showing a configuration of a memory chip 6 in FIG. 1. FIG.
FIG. 5 is a diagram illustrating an example of a signal transmitted in the contact-type transmitting / receiving device.
FIG. 6 is a block diagram illustrating a configuration of a conventional contact-type transmitting / receiving device.
7 is a block diagram showing a configuration of the drive circuit 2 of FIG. 6. FIG.
8 is a block diagram illustrating a configuration of the memory chip 6 in FIG. 6. FIG. 9 is a diagram illustrating an example of a signal transmitted in the contact-type transmitting / receiving device in FIG.
[Explanation of symbols]
4 signal line 6 memory chip 9 drum ground 16 coupling capacitor 22 filter circuit 24 frame ground

Claims (3)

In the contact-type transmission and reception device detachable cartridge in the printer performs a storage device and the data communication of the cartridge in a state of being attached to the printer,
A connecting portion that contacts a contact of the storage device;
One and a signal line connected to the connecting part in order to perform the data communication with the memory device,
A drive circuit connected to the signal line for transmitting data to the signal line;
A high voltage circuit for applying a high voltage to the cartridge for the printer to operate , and a high voltage circuit connected to a drum ground for discharging the charge of the photosensitive drum of the cartridge;
The storage device is connected to the drum ground, the drum ground is connected to the frame ground of the printer, the signal ground of the driving circuit is connected to the frame ground , and the signal is set with the drum ground potential as a reference potential. Data communication is performed using a wire, and when the high-voltage circuit or the photosensitive drum operates and discharges electric charges on the photosensitive drum, the data communication is not performed and the high-voltage circuit or the photosensitive drum is stopped. Then, the data communication is performed when the discharge of the charge on the photosensitive drum is completed . The printer, when the cartridge is to be inserted into the printer, or upon the cartridge Ru is remove from the printer, while the contacts and the connecting portion of the storage device is connected, and, If a state where the rotary shaft is not grounded the drum grounding said photosensitive drum, according to claim 1, wherein further comprising a Rukoto a filter circuit for preventing noise flowing to the signal line Contact-type transceiver. The contact type transmission / reception device according to claim 2, further comprising a coupling capacitor between the filter circuit and the filter circuit.

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