Abstract: A heat roller for a fixing device included in an image forming apparatus has an insulation layer and a conductive layer sequentially formed on the inner periphery thereof. To form each of the insulation layer and conductive layer, a spray gun is inserted into the heat roller. Subsequently, paint, which is a liquid for forming the insulation layer or the conductive layer, is fed under pressure to the spray gun. The paint is radially jetted via the holes of the spray gun and evenly deposits on the inner surface of the heat roller. In this condition, the spray gun is moved in a preselected direction in order to coat the entire inner periphery of the heat roller. After the insulation layer has been formed and then sintered, the conductive layer is formed on the insulation layer and then sintered. The two layers can be formed in a short period of time and provides the heat roller with high quality at low cost. A method of producing the heat roller is also disclosed.

Abstract: A heat-sensitive stencil including a thermoplastic resin film on which a porous resin layer, a water soluble resin layer and a fibrous porous layer are formed in succession. A thin resin layer may be disposed between the thermoplastic resin film and the porous resin layer.

Abstract: A synchronous drive arrangement for a printer of the present invention includes a timing belt passed over drive pulleys each being mounted on a particular print drum. The timing belt is made up of two narrow belt parts produced by dividing a single belt. Assuming that the belt parts have n teeth each, one of the belt parts is shifted from the other belt part by one-half of the number of teeth n. The belt parts are so positioned as to cancel each other's eccentricity component during rotation. The arrangement reduces synchronization errors ascribable to the eccentricity of the timing belt while preserving the low-cost configuration of timing belt connection.

Abstract: A printer with a duplex printing capability of the present invention includes a printing section. In a duplex print mode, the printing section prints either one of a first and a second image formed in a master side by side on the front side of a first sheet. A path selector steers the first sheet coming out of the printing section toward an auxiliary tray. The printing section prints either one of the first and second images on the front side of a second sheet while refeeding means again feeds the first sheet to the printing section to thereby form either one of the first and second images on the reverse side of the first sheet. The path selector steers the first and second sheets toward a sheet discharging section and the auxiliary tray, respectively.

Abstract: A laser diode control board (9), a scanning deflection member control board (12), and an electric signal processing board (11) composing a bar code scanner are formed of individual boards, the laser diode control board (9) is vertically disposed on the side opposite to a collimate lens (5) with respect to the laser diode (2) such that the board face thereof closely faces the laser diode, the electric signal processing board (11) is disposed below the collimate lens (5) along the irradiation direction of a laser beam in a vertical position, the scanning deflection member control board (12) is disposed at the rear in the irradiation direction of the laser beam with respect to the scanning deflection member (8), and the boards are attached to a holding member (4) with the laser diode (2), the collimate lens (5), a mirror (6), the scanning deflection member (8), and a light receiving element (3).

Abstract: A stencil printing method of the present invention intentionally transfers a smaller amount of ink from an upstream print drum to a paper sheet than from a downstream print drum to the same paper sheet such that images printed on the paper sheet one above the other have the same density at the end of a printing cycle. The method obviates a density difference and the roll-up of a paper sheet ascribable to retransfer particular to a single pass, color printing system. A stencil printer for practicing the method is also disclosed.

Abstract: A master making and feeding device for a printer includes a first conveying section and a second conveying section. When the first conveying section is perforating a stencil or after it has perforated a stencil, conveyance drive means drives the second conveying section at a preselected timing in order to feed the leading edge of the stencil to a print drum. At this instant, the conveyance drive means drives the second conveying section such that it conveys the stencil at a higher speed than the first conveying section. The device is capable of reducing a period of time necessary for the leading edge of the perforated stencil to be fed to the print drum and therefore a first print time.

Abstract: A sheet feeding device capable of again feeding, when failed to feed a sheet, the sheet by retry control is disclosed. The sheet feeding device includes a sheet tray loaded with a stack of sheets and a feed roller for sequentially feeding the sheets from the sheet tray one by one. A leading edge sensor is positioned downstream of the feed roller in the direction of sheet feed for sensing the leading edge of the sheet fed from the sheet tray. A registration roller pair is positioned downstream of the leading edge sensor in the direction of sheet feed for conveying the sheet toward an image transfer station at a preselected timing. When the retry control is to be executed, control means varies the content of control in accordance with information output from the leading edge sensor.

Abstract: A multicolor printing method and system including a master making device having plurality of removable ink drums replaceable with each other and a printing device. The plurality of removable ink drums are fed with respective masters to be used for printing, by fixed master feeding devices smaller in number than the removable ink drums. The removable ink drums fed with respective masters are then used by the printing device for printing onto paper. The method and system provides multicolor printing with lower cost, reduced size and accurate registration between the respective masters, as compared to conventional methods and systems.

Abstract: A printer or similar electrophotographic image forming apparatus for forming an image on an optical disk or similar synthetic resin sheet is disclosed. The apparatus of the present invention exerts a preselected pressure for each of image transfer and image fixation to thereby insure high quality images. Further, the apparatus matches the moving speed of the surface of a synthetic resin sheet and the peripheral speed of an image carrier or that of a fixing member. In addition, the apparatus protects the image carrier and fixing member from damage and prevents a parting agent from depositing on at least the image forming range of the image carrier.

Abstract: A heat-sensitive stencil including a thermoplastic resin film on which a porous resin layer, a water soluble resin layer and a fibrous porous layer are formed in succession. A thin resin layer may be disposed between the thermoplastic resin film and the porous resin layer.

Abstract: A sheet feeding device for an image forming apparatus includes a plurality of separator pads each having a particular coefficient of friction with respect to sheets for separating the sheets one by one. An automatic switching mechanism automatically replaces the separator pads. The automatic switching mechanism includes a pad pressure switching section, a pad angle switching section, a ball screw with a worm wheel mounted thereon, a ball nut meshing with the ball screw, a worm meshing with the worm wheel for moving a movable member in the widthwise direction of the sheets via the ball screw, a pad motor for causing the worm to rotate, and a sensor responsive to the position of the movable member. The device automatically selects one of the separator pads and an angle thereof in order to set up optimal sheet feed conditions matching with environmental conditions including temperature and humidity.

Abstract: A data storing device of the present invention includes a cylindrical or hollow cylindrical data storing medium rotatable about its own axis and having a storage layer formed on its circumferential surface for storing data. A head adjoins the storage layer for writing or reading data in or out of the storage layer. A head moving mechanism causes the head to move back and forth along the axis of the data storing medium. A drive motor includes a stator and a rotor spaced from the stator and directly coaxially connected to the data storing medium.

Abstract: A fixing device for an image forming apparatus includes an inverter circuit for induction heating. In the inverter circuit, a main switch Q1 drives one end of a work coil L1 whose other end is connected to a power source. A serial connection of a capacitor Cs and a subswitch Q2 is connected to opposite ends of the coil L1 in parallel such that one end of the capacitor Cs is connected to the power source E. A second capacitor C1 is connected to the subswitch Q2 in parallel. For a capacitance of 0.1 &mgr;F of the capacitor C1, the factor of the coil L1 and that of the capacitor Cs are selected to be between 70 &mgr;H and 100 &mgr;H and between 1.8 &mgr;F and 5 &mgr;F, respectively. The inverter circuit is operable with optimal efficiency in the event of PWM (Pulse Width Modulation) control using a fixed frequency.

Abstract: A stencil printer of the present invention includes a master making section for perforating a master, which includes a porous support and a thermoplastic resin film, in accordance with image data to thereby make a master and wraps the master around a print drum to thereby effect printing. The stencil printer includes a cavity sensor for sensing the condition of cavities existing in the porous support of the stencil. A controller identifies the kind of the stencil by determining the condition of the cavities in accordance with information output from the cavity sensor, so that stable print quality is insured without regard to a difference in cavity ratio between the lots of stencils.

Abstract: A sheet feeding apparatus for image processing systems such as a stencil duplicating machine or a copying machine comprises a sheet feeding time sensor, and a control unit. The control unit compares a sheet feeding time detected by the sheet feeding time sensor with a predetermined reference sheet feeding time, and controls a revolution speed of a sheet feeding roller during or after a sheet feeding operation.

Abstract: A method and a device for determining the amount of ink or similar liquid existing in a container are disclosed. A resonance circuit is arranged on the container storing the liquid. A voltage having a preselected frequency is applied to a drive coil located outside of the container to thereby induce a voltage having a preselected frequency in the resonance circuit. The voltage induced in the resonance circuit, in turn, induces a voltage having a preselected frequency in a sense coil also located outside of the container. The amount of liquid in the container is determined in terms of the voltage induced in the sense coil.

Abstract: An image forming apparatus for forming an image on an optical disk or similar synthetic resin sheet is disclosed. The image forming apparatus feeds and collects the synthetic resin sheet from a conveyance path at the same position. A single space therefore suffices for both of the feed and collection of the synthetic resin sheet, promoting the compact configuration of the apparatus. The conveyance path is inclined relative to the horizontal plane and therefore saves space to thereby promote the efficient use of a limited floor area.

Abstract: A printer including a plurality of print drums and capable of producing, e.g., color printings is disclosed. When a closed position sensor responsive to a door outputs a close signal and when a drum sensor assigned to a print drum to be mounted outputs an absence signal, a controller controls drum drive sections such that a mount/dismount drive section assigned to the print drum to be mounted takes the position corresponding to a mount position. Also, in response to a mount position signal output from a mount position sensor, the controller controls the drum driving device such that the mount/dismount drive section stops at the position corresponding to the mount position. The printer allows an operator thereof to mount the print drums without pressing, e.g., mount/dismount keys each time and thereby saves time.

Abstract: A multicolor printing method using a plurality of ink drums each being loaded with a respective master and a system therefore are disclosed. A plurality of removable ink drums replaceable with each other are fed with respective masters by fixed master feeding devices smaller in number than ink drums via the replacement of the drums and are used for printing. The method and system of the present invention are low cost and enhance downsizing and accurate registration between the masters.